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MANAGEMENT OF LABOR and OBSTRUCTED LABOR

MANAGEMENT OF LABOR and
OBSTRUCTED LABOR

by: Yoshua Viventius
medical student@ 6th grade

Definitions

In order to assess progress in labor, we need to be confident in our definition of active labor and abnormal progress.

Labor Is:
Regular, Frequent Uterine Contractions
+
Cervical Change
(dilatation and effacement)

First stage:

• Latent Phase: is the presence of uterine activity resulting in progressive effacement and dilatation of the cervix preceding the active phase. Latent phase is complete when a primiparous woman reaches 3-4 cm dilatation and cervical length of 0-0.5 cm and a multiparous woman reaches 4-5 cm and cervical length 0.5-1.0 cm. The onset of the latent phase is often difficult to define. It can be difficult to separate from false labor and the true length of this stage is often assessed retrospectively.

• Active phase requires the presence of regular painful contractions leading to more rapid cervical dilatation after 3-4 cm dilatation in a primiparous woman, or 4-5 cm dilatation in a multiparous woman.

Second Stage: (divided into two components)

• Passive: Early descent occurs during the time from full dilatation until an urge to push is felt (about station+2).
• Active: The second component is usually associated with maternal expulsive effort and is the time from the onset of the urge to push until delivery.

Inadequate progress of labor is associated with increases in maternal stress, maternal infection, postpartum hemorrhage and the need for neonatal resuscitation. Tools such as partograms are essential to demonstrate and highlight inadequate progress in labor.

In evaluating the cause of dystocia, we can refer to the three Ps: Powers, Passenger, and Passage. The powers are the most likely to be responsible for dystocia, and are the most readily evaluated and influenced. Ineffective contractions, usually early in labor, are responsible for approximately 2/3 of dystocias in nulliparous women.

Use of the Partograph in Labor

Why the Partograph?

The delivery of a healthy baby and maintenance of a safe delivery for the mother are two goals of all maternity health care givers. A simple instrument called a partograph can aid this basic human right of safe passage. The partograph has been shown to reduce prolonged labor, the need for augmentation, emergency caesarian section and intrapartum stillbirth rates. It should be used in all labor wards and centers for maternity care. The following recommendations are adapted from the World Health Organization recommendations on the use of the partograph: (see Appendix 1A and 1B)

When should one use the partograph?

A partograph should be started on women in labor who have NO complications that require immediate action. Start ONLY when the woman is in labor—this means two contractions in ten minutes (lasting 20 seconds or more) in the latent phase (cervical dilatation of 0-2 cm). In the active phase (cervical dilatation of 3-10 cm), the contractions should be one per ten minutes (lasting 20 seconds or more).

What does the partograph involve?

The partograph demands the assessment of several observations—the first relate to progress of labor (cervical dilatation, descent of the fetal head and uterine contractions). The second set of observations focuses on the fetus: fetal heart rate, membranes and liquor and moulding of the fetal head.

The DILATATION is plotted with an ‘X’. After the first vaginal examination, repeat exams are every four hours (with a more frequent assessment if the woman is multiparous or in advanced labor).

Descent is assessed abdominally in fifths above the pelvic brim. An abdominal examination should be done before the pelvic assessment. Contractions are observed for frequency and duration. The number of contractions in ten minutes is recorded with three ways of shading on the partograph: a) less than 20 seconds b) 20-40 seconds and c) greater than 40 seconds.

Membranes are denoted as:

I=intact C=ruptured and clear M=meconium A=ruptured but absent liquor

Things to remember:

Satisfactory progress means the plot of cervical dilatation will remain ON or LEFT of the ALERT LINE.

The latent phase should not last beyond eight hours. If a mother is admitted in latent phase, start plotting at time zero hours. Once in the active phase, plotting of dilatation is transferred to the ALERT line. If a patient is admitted already in the active phase, dilatation is plotted immediately on the ALERT line.

Listen to fetal heart rate after peak of contractions with a woman on her left side. The fetal heart rate should be 120-160 beats per minute. Record the fetal heart rate every 30 minutes during the first stage of labor. Increasing moulding with a high fetal head is a sign of cephalopelvic disproportion.

Actions on the Partogram:

The Alert Line:

A laboring mother should be referred from a health center to a hospital when the cervical dilatation moves to the RIGHT of the ALERT line. Amniotomy may be performed if the membranes are still intact—she may be observed for a short time prior to transfer. In hospital, movement to the RIGHT of the ALERT line should signal the need for an amniotomy and close observation.

The Action Line:

If the patient’s partograph crosses the ACTION line in a central hospital, active intervention is required. Initially this would include: the start of an intravenous line, bladder catheterization, analgesia and augmentation using oxytocin. These measures would be carried out as long as there was no evidence of fetal distress or obstructed labour.

A vaginal examination should be carried out in three hours, then in two more hours (and every two hours thereafter). The dilatation rate should be 1cm/hour minimum. CHECK the FETAL HEART rate every half hour at minimum when oxytocin is being infused. If these measures are not successful, a cesarian section would be carried out.

Prolonged Latent Phase:

In the case of a woman with a prolonged latent phase (>8 hours), a full assessment must be carried out. Is she truly in labor—if not, abandon the partograph. One may consider an amniotomy plus oxytocin infusion if there is no evidence of fetal distress and the contraction pattern is not satisfactory. A final option is cesarian section—especially if evidence of obstruction or need for imminent delivery.

Antibiotics should be given if the membranes have been ruptured for more than 12 hours.

Fetal distress should be managed aggressively: if the woman is in a health centre, transfer to hospital (for operative delivery) immediately. If the woman is in hospital, stop oxytocin, turn on left side, examine for cord prolapse and hydrate. If the fetal distress does not resolve, an immediate cesarian section is needed.

Etiology of Dystocia

POWERS ineffective contractions
maternal expulsive efforts (second stage)
fetal position

PASSENGER
fetal attitude
fetal size
fetal abnormalities e.g. hydrocephalus

PASSAGE
bony pelvis abnormality

soft tissue causes:
tumours
full bladder/full rectum
vaginal septum

The diagnosis of true or absolute cephalopelvic disproportion (CPD) should be limited to the uncommon instances of real disproportion i.e. inability of the well flexed head (sub-occipito bregmatic presentation) to pass through the bony pelvis. Other presentations may lead to relative cephalopelvic disproportion.

If the woman is making satisfactory progress in labor then the interaction of the three P’s must be adequate. These three variables act together and should generally not be assessed in isolation.

If progress is inadequate, attention should be directed to:

1. Adequate Powers:
Contractions that are…
1) Regular
2) Progressive, which lead to cervical dilatation
3) Frequent ( 2-3 minutes)

2. The Passenger should be assessed for size and malposition. Inadequate powers in active labor may be responsible for malposition. A normal sized infant may present an excessively large diameter to the pelvis because the head is not flexed.

3. The Passage: Clinical examination of the passage may reveal prominent spines or sacrum, a narrow pubic arch or a space-occupying mass in the pelvis. A trial of labor is the only real assessment of the pelvic adequacy.

Prevention and Management of Dystocia

1) Prevention

Accurate Diagnosis of Labor

Some cesarean sections performed for dystocia in nulliparous patients are done in the latent phase of labor. It is likely that at least a portion of these women were not in true labor at the time of labour management interventions or at the time of cesarean section. Appropriate management, of suspected early labor, could result in a decrease in the cesarean section rate.

Management of Prolonged Latent Phase

Different definitions of prolonged latent phase exist including greater than 20 hours in a primip, or a time limit of six hours from admission to health center to 3 cm dilatation. If women are not admitted until they are in active labor, this latter definition becomes irrelevant. Regardless, it is important to separate this entity from false labor.

Management is controversial due to the limited number of published studies.
• The patient should preferably not be admitted to the labor and delivery area.
• Observation, rest and analgesia are favoured over a more active approach of amniotomy and oxytocin induction.

Labor Preparation

For nulliparous women who have attended prenatal education, there may be more rapid progress in labor. Some studies have shown a benefit and others show no difference, but all studies show that women who were prepared for labor had a more positive experience. Trials also show that prenatal education decreases the amount of analgesia used during labor.

Birth Companion

There is now strong evidence that the presence of a supportive companion results in faster progress and less dystocia. This companion should have experience with labouring women, but is not necessarily trained in a health discipline.

Ambulation

It is important to recognize the women’s choice of labor position. Ambulation and upright posture reduces the amount of pain perceived by women in labor. The use of a birth stool often helps if the woman does not want to walk. Upright posture in labor may be useful in reducing backpain and the need for epidural anesthesia. Static supine position may result in aorto-caval compression, hypotension and non-reassuring fetal monitoring.

Analgesia

Some patients in labor reach the limit of their pain tolerance. Furthermore, patients experiencing excessive pain or anxiety have high endogenous catecholamines. This produces a direct inhibitory effect on uterine contractility and establishes a vicious circle of poor uterine progress leading to increased anxiety, leading to increased catecholamines, leading to further impairment of progress. The relief of pain by effective analgesia may allow release of the uterus from the constraints of the endogenous catecholamines and enhance progress in labor. High endogenous catecholamine levels may also adversely affect uterine blood flow and therefore fetal oxygenation.

Amniotomy (ARM*)

Routine early use of amniotomy after 3 cm dilatation shortens the average length of labor, but does not in itself reduce the incidence of dystocia or cesarean section. Early amniotomy at less than 3 cm dilatation may increase the incidence of dystocia.
• ARM: Artificial Rupture of the Membranes

Fetal Size

Fetal size does not significantly affect the progress of labor in first and second stage.

Management

If an arrest disorder is diagnosed, management is as follows:
• Arrest without CPD
– amniotomy
– consider oxytocin augmentation if contractions are inadequate
• Arrest with true CPD
– cesarean section

Oxytocin

In the event of unsatisfactory progress (<0.5cm/hr x 4 hours or arrest of descent for over 1 hour) in the active phase of labor, oxytocin is indicated. Before the use of oxytocin, consideration should be given to the appropriate use of analgesia, hydration, rest and amniotomy.Oxytocin should be used to achieve adequate contractions before operative delivery is considered.Concern is sometimes raised about the use of oxytocin. The principal complications that cause apprehension are fetal compromise and uterine rupture due to uterine hyperstimulation. Judicious use of oxytocin should not result in complications.Fetal hypoxia may occur accompanying spontaneous contractions. Judicious use of oxytocin produces contractions with intrauterine pressures equivalent to spontaneous labor. If the fetus develops signs of fetal hypoxia with these contractions, this is due to pre-existing uteroplacental insufficiency and not to the oxytocin. Inappropriate use of oxytocin may produce hyperstimulation and decrease transplacental oxygen transport to the fetus. In the primigravida rupture of the uterus in association with oxytocin is almost unknown. However care must be taken in the multipara and those with previous uterine surgery.All labor and delivery units must be prepared to manage uterine hyperstimulation whether it is associated with oxytocin use or not. Management of uterine hyperstimulation is outlined in the section on induction of labor. The following are possible complications, their mechanism of occurrence and preventative management, with the use of oxytocin.Adverse Effects of Oxytocin and Their PreventionAdverse Effects Mechanism PreventionFetal compromise Hyperstimulation Correct doseUterine rupture Hyperstimulation Correct doseEach woman’s uterus varies in its sensitivity to oxytocin. Even in the same uterus, the sensitivity may change during the course of labor. The dose must be sufficient to achieve adequate contractions. Protocols or guidelines for the administration of oxytocin vary but suggest starting with a low dose and small increments at intervals of 30 minutes. Starting incremental dosages for augmentation may be less than those for induction.Augmentation of LaborInitial dose of oxytocin 1-2mU/minIncrease interval Every 30 minutesDosage increment 1-2mUUsual dose for good labor 2-12mU/minIt is important to allow adequate time for oxytocin to work. This is especially true if it is started when the cervix is less than 5 cm dilated. Do not expect to see immediate progress.For the conversion to the equivalent to drops per minute (20 drops=1ml):Oxytocin Normal Saline Drops10 unites 500 ml 1mu = 1 drop5 unites 1 lt 1mu = 4 drops10 unites in 1 lt 1mu = 2 dropsActive Management of LaborActive management of labor encompasses the following principles:• Rigorous diagnosis of labor• Close surveillance of progress of labor by partogram• Continuous support in labor• Early intervention to correct inadequate progress of labor:• ARM• OxytocinThis has been shown to reduce the incidence of dystocia and cesarean sections. Management of the Prolonged Second Stage Setting an arbitrary time limit for the second stage in the absence of suspected fetal compromise, is not well founded. Women should not be encouraged to push until the head has descended to the pelvic floor and they feel the urge to do so. If no urge to push occurs after one hour of second stage, reassess the contractions and consider the use of oxytocin if contractions are inadequate. A lack of descent in the absence of moulding or caput is likely due to inadequate contractions.Summary

Prevention of Dystocia
• Avoid unnecessary induction
• Admit only women in active labor
• Encourage ambulation and upright posture
• Encourage the use of prenatal education
• Continuous support of laboring women
• Use appropriate analgesia

Management of Dystocia
• Appropriate assessment of adequate progress in labor
• Appropriate intervention when necessary
 Amniotomy
 Analgesia
 Rest
 Ambulation
 Augmentation
 Cesarean sections

OBSTRUCTED LABOR

Definitions

“Failure of descent of the fetus in the birth canal for mechanical reasons in spite of good uterine contractions”. (Philpott, 1982)

Incidence
1 – 3%

Risks Associated with Neglected Obstructed Labor

Fetal:
• Asphyxia
• Sepsis
• Death

Maternal:
• Sepsis
• Uterine rupture
• Hemorrhage
• Fistula (Vesico-vaginal, recto-vaginal)
• Death

Etiology of Obstructed Labor

Fetal – Pelvic Disproportion:

Malpresentations
– Face
– Brow
– Shoulder/arm presentation – Transverse lie
– Breech
– Compound presentation

Malposition- Persistent occipito posterior
– Persistent occipito transverse

Malformations
– Hydrocephalus
– Abdominal tumors (eg. Wilms Tumor)
– Cystic Hygroma
-Conjoined twins

Maternal

•Small pelvis
– Childhood malnutrition
– Contracted or deformed bony pelvis

•Soft tissue tumors of the pelvis
– Uterine fibroids
– Ovarian tumors
– Rectal tumors

Clinical Features of Obstructed Labor

In most cases, prolonged labor preceeds obstruction. However, in the grand multiparous patient labor may be quick and relatively silent, and in the presence of a malpresentation, such as a transverse lie, obstructed labor may rapidly occur.

Clinical Presentation of a Patient with Obstructed Labor:

Dehydration

Dehydration is due to muscular activity in the absence of adequate fluid intake. Signs and symptoms will include hot and dry skin with loss of tissue turgor.

• Oliguria

Decreased urinary output occurs in association with the patient’s state of dehydration.

• Keto-acidosis

Metabolic acidosis develops, from accumulation of lactic acid produced by the prolonged contractions of uterine and skeletal muscles. With inadequate caloric intake, endogenous tissue breakdown occurs, and the catabolism of fat in the absence of carbohydrates leads to the production of ketones which further increases the acidosis. Dehydration exaggerates the acidaemia because anions accumulate due to the diminished urinary output. In a response to restore the acid base equilibrium, potassium is mobilized from the cells, which diminishes the activity of the involuntary muscles.

The clinical signs of keto-acidosis are: a rapid pulse in association with deep and rapid respiration and pyrexia. Acetone is present in the urine, and the bowel is frequently distended and atonic due to hypokalemia.

• Sepsis

Infection that is frequently established by the time-prolonged labor has reached the stage of obstruction, particularly if the membranes have been ruptured for a long time. The introduction of pathogens often occurs with un-sterile vaginal examinations or manipulations. Even in the absence of vaginal interventions, infection will develop in the birth canal in association with prolonged obstructed labor.

The clinical signs of infection are purulent vaginal discharge, pyrexia and tachycardia. In advanced cases, infections due to gas-forming organisms may produce a crackling sensation when the uterus is palpated.

When the fetus has been dead for several days, significant gas may be produced from putrefaction and the uterus becomes distended and tympanitic. The terminal signs of severe intrapartum infection are septic shock with circulatory collapse, hypotension, a rapid thready pulse with subnormal temperature.

State of the Uterus

In multigravid, the uterus reacts to obstruction by frequent and stronger contractions of the upper segment. Meanwhile, the lower segment continues to retract and already thinned by circumferential dilatation in the first stage of labor, elongates and becomes progressively thinner. As the contractions continue, progressive retraction and thinning of the lower segment continues and the junction ring between the lower and upper segment rises progressively, often up to the level of the umbilicus. This is called a pathological ring or Bandl’s Ring.

In the primigravid patient, obstruction will usually occur before full dilatation. If the obstruction is neglected the following sequence of events will occur:

• Prolonged uterine activity may lead to reduced intervillous blood flow and fetal asphyxia
• Fetal trauma associated with operative vaginal delivery
• Avascular pressure necrosis from the fetal presenting part. This develops in a ring formation at the obstruction site leading to sloughing of the lower uterine segment and cervix.

Palpation of the uterus and observation of contractions provides important information. In the early stages of obstruction the uterus may contract vigorously and frequently, with little relaxation between contractions. This is followed by a continuous spasm when the uterus is hard, uniformly convex, and tender to pressure – particularly over the distended lower uterine segment. The patient is usually not in constant pain but feels continuous discomfort.

In obstructed labor, asphyxia is likely to have caused intra-uterine fetal death by the time the patient presents for treatment. The asphyxia results from interference with placental exchange of gas between fetus and mother through the mechanism of strong repetitive uterine contractions over a long period of time or the development of a contracted uterus.

Ruptured Uterus

The clinical findings may vary from mild and non-specific to an obvious clinical crisis and abdominal catastrophe. The following signs and symptoms of impending, or early, uterine rupture are not consistent but can aid early detection:

– Persistent lower uterine segment pain and tenderness between contractions
– Swelling and crepitus of lower uterine segment
– Vaginal bleeding
– Maternal tachycardia, hypotension and syncope
– Haematuria
– Fetal heart rate abnormalities: tachycardia, variable and late deceleration. This is the most reliable
warning sign.

The classic signs and symptoms of complete uterine rupture are:

– Sudden onset of tearing abdominal pain
– Cessation of uterine contractions
– Vaginal bleeding
– Recession of the presenting part
– Absent fetal heart
– Signs of intra-abdominal hemorrhage associated with hypovolaemic shock.

The lower uterine segment may rupture with few dramatic signs and symptoms. The thin avascular scar of a previous lower uterine segment cesarean section may rupture with little bleeding and labor continue uneventfully- rupture of the uterus becoming apparent in the post partum period.

State of the Bladder

During labour, the bladder is normally displaced out of the pelvis and becomes palpable above the symphysis pubis. Compression between the back of the symphysis and the presenting part may prevent the patient from emptying her bladder and make catheterisation impossible. The bladder forms a tender swelling above the symphysis. This overlies the stretched lower uterine segment, and the transverse depression at the junction of the superior border of the bladder and the lower segment of the uterus may be confused with a pathological retraction ring.

Prolonged compression traumatizes the bladder, so blood stained urine is a fairly constant feature of obstructed labor but does not necessarily mean the uterus has ruptured.

Vaginal Findings

Obstructed labor often produces oedema of the lower vagina and vulva. Associated sepsis often leads to a thick offensive vaginal discharge. Bleeding is of significant concern, as it usually indicates the uterus has ruptured.

Cervical Findings

In cephalic presentations full cervical dilation will usually occur as the moulded fetal head is driven down through the cervix. With shoulder or compound presentations, a rim of cervix usually persists because the presenting part is arrested at a higher level.

By the time obstruction has occurred, the caput succedaneum makes identification of the presentation and position very difficult. In vertex presentations, a large caput on the apex of an extremely molded head may reach the outlet when the greatest diameter is still above the brim. Therefore, more reliance should be placed on the abdominal findings when deciding the level or station of the head.

Complications of Obstructed Labor

Maternal
– Ruptured Uterus
– Vesico-Vaginal Fistulae (VVF)
– Recto-Vaginal Fistulae (RVF)
– Pueperal sepsis

• Extensive sloughing heals by fibrosis leading to almost complete stenosis of the vagina and dyspareunia/ apareunia
• Osteitis pubis – infection of pubic bone after damage to the periosteum and superficial cortex by pressure necrosis

Fetal
– Asphyxia / cerebral palsy
– Neonatal sepsis
– Death

Treatment

• Prevention – In most cases, obstructed labor can be prevented by:

– Good nutrition in childhood
– Promotion of appropriate and accessible antenatal care with health care providers trained in history and
physical examination skills
– Use of a partogram in the health unit when the patient is in labor
– The development of appropriate and timely referral systems.

•The standard procedure for obstructed labor is cesarean section when the diagnosis has been made.

•Prolonged or neglected obstructed labor (uterus intact)

1. If the fetus is still alive – The patient should be prepared for delivery with simultaneously attention to the sequelae of prolonged labor.

– Fluid electolyte imbalance
– Control of infections with broad spectrum antibiotics and tetanus prophylaxis

Method of delivery:
– Vacuum in cases of mild disproportion
– Forceps: which will require special skills for mid cavity operations
– Symphysiotomy (see Appendix 2)

2. With a dead fetus – If the fetus is dead, destructive operations may be considered, particularly if the mother’s condition is morbid. Resuscitation of the mother is essential before proceeding with a destructive procedure. This resuscitation should include:

– Correction of fluid and electrolyte imbalance
– Control infection
– Be prepared to prevent/treat post partum hemorrhage

• Ruptured Uterus

1. Prompt management of hypovolaemia

2. Laparotomy:
– Remove fetus and placenta

3. Secure hemostasis :
– Deliver the uterus out of the abdominal incision. Assistant’s hands may hold the uterus and with fingers and thumbs occlude the uterine vessels.
– Control the bleeding edges of the uterine laceration with ring forceps.
– Manual compression of the aorta will often enable the surgeon to identify the extent of the lacerations in the uterus.
– Uterine artery ligation should be considered to reduce blood loss before proceeding to definitive surgery.
– Internal iliac artery ligation may be necessary to control bleeding in the base of the broad ligament.

Before carrying out any surgical procedures on major vessels, identification of the course of the uretery should be undertaken in order to avoid ureteric injury. The integrity of the bladder should always be carefully reviewed, as the bladder wall may frequently be involved in a lower uterine segment rupture.

Surgical Options:

The choice of operative procedure is dependant on a number of factors including the patient’s condition, type of rupture, facilities available, and experience of the surgeon. 5
– Total hysterectomy
– Subtotal hysterectomy
– -Laceration repair and tubal ligation
– Laceration repair alone

Destructive Procedures

– Craniotomy
– Decapitation
– Evisceration
– Cleidotomy

In a series reported by Raksha Anura on 33 patients who underwent destructive operations, craniotomy was the most common destructive procedure and the main indication was hydrocephalus.5

The performance of destructive fetal operation will depend on local facilities and experience.

Before performing any destructive procedure, it is important to ensure the bladder is empty. The aim of the treatment is to deliver the mother by the safest possible method. The operative vaginal delivery and destructive procedures must be performed in an operating theatre where a set of laporatomy instruments are available for immediate use.

References:
1. Kwast B et al., World Health Organization partograph in management of labour. Lancet, 1994, 343:1399-1404.
2. WHO. “Preventing Prolonged Labour: A Practical Guide.” The Partograph. Geneva: Maternal Health and Safe Motherhood Programme, Division of Family Health, 1994.
3. SOGC “DYSTOCIA”. SOGC Policy Statement No. 40, October 1995
4. Keirse MJNC, Chalmers I. In: Chalmers, Enkin, Keirse (Eds). Effective Care in Pregnancy and Childbirth. Oxford University Press, Oxford, England, 1989.
5. Friedman EA. Labour: Clinical evaluation and management. Second edition (New York). Appleton Century Crofs. 1976. Studd JWW (Ed). The Management of Labour. Oxford: Blackwell Scientific Publications, 1985.
6. O’Driscoll K, Foley M, MacDonald D. Active management of labor as an alternative to caesarean section for dystocia. Obstet Gynecol 1984; 63: 485-90
7. Akoury HA, BrodieG, Caddick R, McLaughlin VD, Pugh PA. Active Management of Labor and Operative Delivery in Nulliparous Women. AM J Obstet Gynecol 1988;255

Guidelines on Labor Induction Revised

July 24, 2009 — On July 21, the American College of Obstetricians and Gynecologists (ACOG) issued revised guidelines on when and how to induce labor in pregnant women. The updated recommendations are published as a Practice Bulletin, “Induction of Labor,” in the August issue of Obstetrics & Gynecology. The bulletin aims to guide physicians regarding their choice of induction methods that may be most suitable in specific settings and to elucidate the safety requirements, risks, and benefits of various regimens to induce labor.

Benefits vs Risks of Labor Induction

For the last 2 decades, the rate of labor induction in the United States has more than doubled, with more than 22% of all pregnant women in 2006 having labor induced. This increase in use necessitates a careful review of indications, risks, and benefits.

The goal of labor induction is to stimulate uterine contractions before the spontaneous onset of labor, resulting in vaginal delivery. The benefits of labor induction must be weighed against the potential maternal and fetal risks associated with this procedure. When the benefits of expeditious delivery are greater than the risks of continuing the pregnancy, inducing labor can be justified as a therapeutic intervention.

“There are certain health conditions, in either the woman or the fetus, where the benefit of inducing labor is clear-cut,” coauthor Susan Ramin, MD, from the University of Texas Medical School in Houston, said in a news release. “And, there are some nonmedical situations in which induction also may be prudent, for instance, in rural areas where the distance to the hospital is just too great to risk waiting for spontaneous labor to happen at home.”

Recommendations Based on Sound Evidence

Based on evidence from methodologically sound outcomes-based research, the bulletin attempts to review current methods for cervical ripening and for inducing labor and to summarize the efficacy of these approaches. Also highlighted are indications for and contraindications to inducting labor, pharmacologic characteristics of various agents used for cervical ripening, regimens used for labor induction, and the requirements for safe clinical use of these techniques.

The bulletin authors searched the MEDLINE database, the Cochrane Library, and ACOG’s own internal resources and documents to identify pertinent English-language articles published between January 1985 and January 2009. Although articles reporting results of original research were given priority, review articles and commentaries were also consulted, as were guidelines published by organizations or institutions such as ACOG and the National Institutes of Health. However, abstracts of research presented at symposia and scientific conferences were excluded. Expert opinions from obstetrician-gynecologists were used when reliable research evidence was not available.

Indications for Labor Induction

Possible indications for labor induction may include gestational or chronic hypertension, preeclampsia, eclampsia, diabetes, premature rupture of membranes, severe fetal growth restriction, and postterm pregnancy. However, physicians should decide whether labor induction is warranted on a case-by-case basis, after consideration of maternal and infant conditions, cervical status, gestational age, and other factors.

Contraindications to labor induction include transverse fetal position, umbilical cord prolapse, active genital herpes infection, placenta previa, and a history of previous myomectomy.

When labor induction is deemed necessary, the gestational age of the fetus should be determined to be at least 39 weeks, or there must be evidence of fetal lung maturity.

The first step in labor induction is cervical ripening using drugs or mechanical cervical dilators to dilate the cervix sufficiently before labor is induced. The next step is to induce labor using oxytocin, membrane stripping, rupture of the amniotic membrane, or nipple stimulation.

Misoprostol, which is approved for treatment of peptic ulcers, is often used off-label for cervical ripening as well as for labor induction. In women who have had any previous cesarean delivery, however, inducing labor with misoprostol may increase risk for uterine rupture and should therefore be avoided.

Clinical Recommendations

Specific clinical recommendations and conclusions, all based on good and consistent scientific evidence (level A), are as follows:

* For cervical ripening and labor induction, prostaglandin E (PGE) analogues are effective.
* When labor induction is indicated, low-dose or high-dose oxytocin regimens are appropriate.
* Regardless of Bishop score, the most efficient method of labor induction before 28 weeks of gestation appears to be vaginal misoprostol. However, infusion of high-dose oxytocin is also an acceptable option.
* For cervical ripening and induction of labor, an appropriate initial dose of misoprostol is approximately 25 µg, with frequency of administration not to exceed 1 dose every 3 to 6 hours.
* For induction of labor in women with premature rupture of membranes, intravaginal PGE2 appears to be safe and effective.
* In women with previous cesarean delivery or major uterine surgery, the use of misoprostol should be avoided in the third trimester because it has been linked to a greater risk for uterine rupture.
* The Foley catheter is a reasonable, effective option to promote cervical ripening and labor induction.

An additional clinical recommendation, based on limited or inconsistent evidence (level B), is that misoprostol, 50 µg every 6 hours, to induce labor may be appropriate in some situations. However, higher doses are linked to a greater risk for uterine tachysystole with fetal heart rate (FHR) decelerations and other complications.

“A physician capable of performing a cesarean should be readily available any time induction is used in the event that the induction isn’t successful in producing a vaginal delivery,” Dr. Ramin concluded. “These guidelines will help physicians utilize the most appropriate method depending on the unique characteristics of the pregnant woman and her fetus.”

Obstet Gynecol. 2009;114:386-397.
Clinical Context

Labor induction occurs in more than 22% of pregnant women in the United States and has doubled in rate between 1990 and 2006, according to Martin and colleagues in the January 7, 2009, issue of National Vital Statistics Reports. Cervical ripening methods include mechanical dilation, synthetic PGE1, and PGE2. Mechanical dilation methods are hygroscopic dilators, osmotic dilators, Foley catheters, double-balloon devices, and extra-amniotic saline infusion. The PGE1 analogue, misoprostol, can be used for cervical ripening and labor induction. PGE2 is available as dinoprostone gel or as a vaginal insert. Methods of labor induction include oxytocin, membrane stripping, amniotomy, and nipple stimulation.

This guideline from the ACOG describes the indications for and contraindications to labor induction, methods for cervical ripening, methods for labor induction, and recommendations for use of these methods.

Study Highlights

* Indications for labor induction include abruptio placentae, chorioamnionitis, fetal demise, gestational hypertension, preeclampsia, eclampsia, premature rupture of membranes, postterm pregnancy, maternal medical conditions, and fetal compromise.
* Labor might be induced for logistic reasons if term gestation is confirmed.
* Contraindications to labor induction include vasa previa or complete placenta previa, transverse fetal lie, umbilical cord prolapsed, previous classic cesarean delivery, active genital herpes infection, and previous myomectomy entering the endometrial cavity.
* Criteria for cervical ripening or labor induction are assessment of gestational age and risk to mother or fetus; assessment of cervix, pelvis, fetal size, and presentation; FHR and uterine contraction monitoring; patient counseling; and capability for cesarean delivery.
* PGE analogues are effective methods for cervical ripening and inducing labor.
* An effective alternative for cervical ripening and inducing labor is a Foley catheter, which reduces the duration of labor and risk for cesarean delivery.
* Misoprostol initial dose is 25 µg every 3 to 6 hours intravaginally.
* Misoprostol doses of 50 µg every 6 hours might be indicated but are linked with the risk for uterine tachysystole with FHR decelerations.
* Buccal and sublingual misoprostol for cervical ripening or labor induction are not recommended because of lack of safety data.
* Misoprostol should be avoided in the third trimester in women with prior cesarean delivery or major uterine surgery because of an increased risk for uterine rupture.
* Dinoprostone can be administered intracervically or intravaginally.
* Uterine tachysystole with or without FHR changes occur more commonly with vaginal misoprostol vs vaginal or intracervical PGE2 and oxytocin.
* The management of uterine tachysystole and category III FHR tracing includes maternal repositioning, supplemental oxygen, subcutaneous terbutaline, and decrease or discontinuation of oxytocin.
* Cesarean delivery might be necessary for persistent tachysystole or FHR abnormalities.
* After PGE use, surveillance should include initial continuous FHR and uterine activity monitoring and recumbent position for the pregnant patient.
* Limited data show that outpatient use of intravaginal PGE2 gel for 5 days, controlled-release PGE2, and a Foley catheter appear to be effective and safe.
* Oxytocin for labor induction can be given as low dose (initial 0.5 – 2 mU/minute with incremental increases of 1 – 2 mU/minute) or high dose (initial 6 mU/minute with increases of 3 – 6 mU/minute).
* The maximal oxytocin dose is unknown.
* The main adverse effects of oxytocin are dose-related uterine tachysystole and category II or category III FHR tracings.
* The risks for amniotomy are umbilical cord prolapse, chorioamnionitis, umbilical cord compression, vasa previa rupture, and the risk for vertical transmission of HIV.
* Amniotic membrane stripping risks include bleeding from placenta previa or low-lying placenta and amniotomy.
* Breast stimulation is linked with uterine tachysystole with FHR decelerations and increased trend in perinatal death.
* In women with premature rupture of membranes at term, labor can be induced with oxytocin or PGE, but there are insufficient data on mechanical dilator use.
* Management of intrauterine fetal demise depends on gestational age, uterine scar, and maternal preference.
* For intrauterine fetal demise in the second trimester, dilation and evacuation is an option.
* For intrauterine demise before 28 weeks’ gestational age, misoprostol is the most efficient method; high-dose oxytocin is also an option.

Clinical Implications

* In pregnant women who require cervical ripening and labor induction, PGE analogues are effective, and the Foley catheter is an effective alternative. Labor can be induced with low-dose or high-dose oxytoxin regimens.
* For intrauterine fetal demise before 28 weeks of gestation, the most efficient method of labor induction is vaginal misoprostol. Misoprostol use should be avoided in the third trimester in women with previous cesarean delivery or major uterine surgery because of a link with an increased risk for uterine rupture.

No Benefit in Lowering BP Below "Standard" 140/90 mm Hg

July 23, 2009 — A new review has found that lowering blood pressure below the “standard” target of 140/90 mm Hg is not beneficial in terms of reducing mortality or morbidity [1]. Dr Jose Agustin Arguedas (Universidad de Costa Rica, San Pedro de Montes de Oca) and colleagues report their findings online July 8, 2009 in the Cochrane Database of Systematic Reviews.

They explain that over the past five years, a trend toward lower targets has been recommended by hypertension experts who set treatment guidelines, “based on the assumption that the use of drugs to bring the BP lower than 140/90 mm Hg will reduce heart attack and stroke.” But this approach “is not proven,” they point out.

Arguedas told heartwire that they reviewed seven trials with more than 22 000 subjects comparing lower or standard diastolic BP targets, but they were unable to identify any studies comparing different systolic BP targets. “We found there is no evidence that reaching a target of below 90 mm Hg diastolic BP will provide additional clinical benefit, but we can’t say whether lowering systolic BP below 140 mm Hg will be beneficial or not; there are no data.”

Dr Franz Messerli (St Luke Roosevelt Hospital, New York, NY), who was not involved with this review, told heartwire that there is no question that the 140/90-mm-Hg BP limit is “absolutely arbitrary, and the benefits of antihypertensive medications are most obvious in patients with the highest BP. The closer we get to ‘normotension,’ the more difficult it becomes to show benefits of BP lowering.

“The Lewington meta-analysis of one million patients has convincingly shown that people fare better—ie, have fewer strokes and heart attacks—when their ‘usual’ BP is 115/70 mm Hg compared with those with a ‘usual’ BP of 130/80,” Messerli adds. “However there are no data and probably never will be that lowering BP from 130/80 mm Hg to 115/70 mm Hg confers any benefits,” he says.

Further Review Required in at-Risk Patients

Attempting to achieve lower BP targets has several consequences, the researchers note; “the most obvious is the need for large doses and increased number of antihypertensive drugs. This has inconvenience and economic costs to patients. More drugs and higher doses will also increase adverse drug effects, which if serious could negate any potential benefit associated with lower BP.” There is also the potential that lowering BP too much may cause adverse cardiovascular (CV) events, the so-called “J-curve” phenomenon, they observe.

In their review, they included: the Modification of Diet in Renal Disease (MDRD) trial; the Hypertension Optimal Treatment (HOT) study; the BP Control in Diabetes (ABCD) trials H and N; the African American Study of Kidney Disease and Hypertension (AASK), and the Renoprotection in Patients With Nondiabetic Chronic Renal Disease (REIN-2) study.

They found that, despite a 4/3-mm-Hg-greater achieved reduction in systolic/diastolic BP (p < 0.001), attempting to achieve “lower targets” instead of “standard targets” did not change: * Total mortality (relative risk 0.92). * Myocardial infarction (MI; RR 0.90). * Stroke (RR 0.99). * Congestive heart failure (RR 0.88). * Major cardiovascular events (RR 0.94). * End-stage renal disease (RR 1.01).”This strategy did not prolong survival or reduce stroke, heart attack, heart failure, or kidney failure,” they note. “More trials are needed, but at present there is no evidence to support aiming for a blood-pressure target lower than 140/90 mm Hg in any hypertensive patient.”The researchers say they were unable to fully assess the net health effect of lower targets due to lack of information regarding all total serious adverse events and withdrawals due to adverse effects in six of seven trials.
Trials Needed to Compare Lower With Standard Systolic Targets

Arguedas and his colleagues note that a lower BP target of 130/80 mm Hg is currently recommended for at-risk patients, and they did perform a sensitivity analysis in diabetic and kidney-disease patients, which did not show significant benefits for treating to targets of lower than 135/85 mm Hg. “However, in these two populations, the evidence for a lack of benefit is less robust,” they note.

Arguedas told heartwire that properly conducted randomized controlled trials are needed comparing lower systolic BP targets with standard ones in the general population and also in specific subgroups of at-risk patients.

One such study is the ongoing Action to Control Cardiovascular Disease in Diabetes (ACCORD) blood-pressure trial—an unmasked, open-label, randomized trial with participants randomized to one of two groups with different treatment goals: systolic blood pressure < 120 mm Hg for the more intensive goal, and systolic blood pressure < 140 mm Hg for the less intensive goal [2].The primary outcome measure is the first occurrence of a major CVD event, specifically nonfatal MI or stroke, or cardiovascular death during a follow-up period ranging from four to eight years. The results should provide some of the first definitive clinical-trial data on the possible benefit of treating to a more aggressive systolic blood-pressure goal.In the meantime, says Arguedas, “We are doing another separate systematic review specifically in patients with diabetes and chronic kidney disease to see whether targets lower than 130/80 mm Hg change morbidity or mortality as compared with standard targets.”References

1. Arguedas JA, Perez MI, Wright JM. Treatment blood pressure targets for hypertension. Cochrane Database Syst Rev 2009; 3:CD004349.
2. Cushman WC, Grimm RH Jr, Cutler JA, et al. Rationale and design for the blood pressure intervention of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Am J Cardiol 2007; 99(12A):44i-55i.

Clinical Context

There is a continuous adverse relationship between BP and CV events, but despite practice guidelines recommending control of BP with a threshold of 140/90 mm Hg, it is unclear if lower thresholds are associated with improved outcomes. In recent practice guidelines, lower thresholds have been recommended for patients with comorbidities such as diabetes or renal disease, but data for patients without these comorbidities are scarce.

This is a systematic review to examine if lower targeted BP is achieved in trials with lower vs higher targets and if lower targets are associated with improved clinical outcomes.

Tobacco Smoking May Increase Risk for Tuberculosis

September 1, 2009 — Tobacco smoking is associated with a 2-fold increased risk for active tuberculosis, according to the results of a prospective Taiwan cohort study reported in the September 1 issue of the American Journal of Respiratory and Critical Care Medicine.

“Previous case-control studies and a small number of cohort studies in high-risk populations have found an association between tobacco and active tuberculosis, but no cohort studies have been conducted in the general population on this association to date,” write Hsien-Ho Lin, MD, ScD, from Harvard School of Public Health in Boston, Massachusetts, and colleagues.

The goal of the study was to evaluate the association between tobacco smoking and active tuberculosis in a general population cohort of 17,699 participants older than 12 years enrolled in the Taiwan National Health Interview Survey. An in-person interview at baseline determined smoking status and other covariates. During follow-up from 2001 to 2004, incident cases of active tuberculosis were identified with use of the National Health Insurance database. After adjustment for age, sex, alcohol intake, socioeconomic status, and other covariates, the association between smoking status and active tuberculosis was estimated with multivariate logistic regression.

During the 3.3 years of follow-up, there were 57 new cases of active tuberculosis. Current smoking was linked to an increased risk for active tuberculosis (adjusted odds ratio [OR], 1.94; 95% confidence interval, 1.01 – 3.73). Compared with patients older than 65 years, those younger than 65 years showed a stronger association between current smoking and the risk for active tuberculosis (adjusted OR, 3.04 vs 0.78; P for interaction = .036). There were significant dose-response associations for cigarettes per day (P for trend = .0036), years of smoking (P for trend = 0.023), and pack-years (P for trend = .0023).

“Tobacco smoking was associated with a twofold increased risk of active tuberculosis in a representative cohort of Taiwan’s population,” the study authors write. “The finding that smoking increases the risk of tuberculosis suggests that tobacco control be considered as an important component in the global effort to eliminate tuberculosis.”

Limitations of this study include deaths not recorded in the National Health Insurance database, short duration of follow-up, and lack of data from bacteriologic studies for the diagnosis of tuberculosis.

“Based on the results from our and other observational studies, policy makers and public health personnel should consider addressing tobacco cessation as part of TB [tuberculosis] control,” the study authors conclude. “Recent studies suggest that introducing brief tobacco cessation advice may be feasible among TB patients, and an integrated approach has been proposed to monitor smoking cessation in TB care. From the perspective of prevention, the target of smoking cessation should aim beyond TB patients to reach high-risk populations who are likely to benefit most from cessation.”

This study was supported by a grant from the World Bank through the International Union against Tuberculosis and Lung Disease and a fellowship from the Taiwan American Foundation of Boston. Some of the study authors have disclosed various financial relationships with Abt Associates, Bristol-Myers Squibb, and/or Pulmatrix.

Am J Respir Crit Care Med. 2009;180:475-480. Abstract

Clinical Context

Tuberculosis is among the leading causes of death from infectious diseases in the world. The World Health Organization has a goal to lower the incidence of tuberculosis to less than 1 case per million by 2050, so identifying and managing modifiable risk factors is a priority. An estimated 1.3 billion people worldwide smoke tobacco products, and a positive association has been shown between smoking and active tuberculosis, as well as mortality from tuberculosis based on case-control and cross-sectional studies. However, there has been a lack of longitudinal population-based studies demonstrating this association.

This is a prospective cohort study using Taiwan’s National Health Interview Survey to examine the association between tobacco smoking and the subsequent risk for tuberculosis at 3 years of follow-up. In Taiwan, the smoking rate is more than 40% among men and 4% among women.

Study Highlights

* A cohort of 17,699 patients from the National Health Interview Survey were observed from 2001 to 2004 and incident cases of active tuberculosis identified from the National Health Insurance database.
* The National Health Insurance database included 97% of Taiwan’s residents in 2001.
* At baseline, participant demographics, smoking behaviors, and other lifestyle factors were obtained by in-person interview.
* Data were available on the number of cigarettes smoked per day, years of smoking, age of onset of smoking, and exposure to secondhand smoke at home.
* Ever-smokers were defined as those who had smoked more than 100 cigarettes in their lifetime, current smokers as those who smoked within the past month, and former smokers as those who had not smoked in the past 1 month.
* Covariates examined included alcohol use, sex, income, marital status, employment, and indigenous community status.
* The primary outcome was active tuberculosis cases derived from the National Health Insurance database with use of International Classification of Diseases, Ninth Revision, Clinical Modification, codes plus prescription of more than 2 antituberculosis medications for more than 28 days.
* Overall among the participants, 3893 were current smokers, 552 were former smokers, and 13,254 were never-smokers.
* 40.0% of men and 4.2% of women smoked at baseline.
* Among current smokers, 22% were from low-income homes, 64% were married or cohabiting, 22% were regular alcohol drinkers, and 70% were employed.
* At baseline, median age was 39 years for current smokers, 57 years for former smokers, and 37 years for never-smokers.
* Active tuberculosis occurred in 24 current smokers, 3 former smokers, and 30 never-smokers.
* Compared with never smoking, the crude OR for incident tuberculosis for ever smoking and current smoking were 2.69 and 2.73, respectively.
* After adjustment for confounders, only current smoking was significantly associated with active tuberculosis, with an OR of 1.94.
* The association was affected by age.
* The risk for active tuberculosis with current smoking was higher for those 65 years and younger vs those older than 65 years (OR, 3.04 for the comparison).
* There was no effect of sex or living in an indigenous community on the risk for incident tuberculosis.
* Although the prevalence of tuberculosis was higher in men vs women, the OR for incident tuberculosis in men was not increased vs women once adjusted for current smoking.
* Thus, the authors postulated that the association between smoking and tuberculosis was not dependent on sex.
* The association between ever smoking and tuberculosis was not significant.
* Among current smokers, there was a significant linear dose-response association between the number of cigarettes smoked daily, years of smoking, and pack-years and incident tuberculosis.
* Among the 13,033 never-smokers exposed to secondhand smoke, 30 cases of incident tuberculosis occurred with an adjusted OR of 1.25 for active tuberculosis, but this association was not statistically significant.
* There was no dose-response association between passive exposure to smoking and the risk for tuberculosis.
* Overall, 17% of incident tuberculosis cases were attributable to smoking.
* When extrapolated to the national population, 2841 of 16,580 cases reported in Taiwan in 2005 were attributable to smoking.
* The authors concluded that current, but not ever, smoking was associated with an increased risk for incident tuberculosis and a greater intensity of smoking was associated with higher risk.


Clinical Implications

* Current, but not ever, smoking is associated with a higher risk for incident active tuberculosis, and this risk is greater in those younger than 65 years.
* There is a dose-response association for current smoking and incident tuberculosis but not for passive exposure to cigarette smoke and incident tuberculosis.

WHO Issues Guidelines for Antiviral Treatment of H1N1 and Other Influenza

August 27, 2009 — The World Health Organization (WHO) has issued guidelines for antiviral treatment of novel influenza A (H1N1) and other influenza. The purpose of the new recommendations, which were posted online August 20, is to provide a basis for advice to clinicians regarding the use of the currently available antivirals for patients presenting with illness caused by influenza virus infection, as well as considerations regarding potential use of these antiviral medications for chemoprophylaxis.

On the basis of a review of data collected with previously circulating strains, and treatment of human H5N1 influenza virus infections, the new guidelines expand on recommendations published in May 2009, titled “Clinical management of human infection with new influenza A (H1N1) virus: Initial guidance.” These new guidelines do not change recommendations in the WHO rapid advice guidelines on pharmacological management of humans infected with highly pathogenic avian influenza A (H5N1) virus.

“In April 2009, the [WHO] received reports of sustained person to person infections with [H1N1] virus in Mexico and the United States,” write Edgar Bautista, from Médico Neumólogo Intensivista, Jefe de UCI-INER in Mexico, and colleagues. “Subsequent international spread led WHO to declare on 11 June 2009 that the first influenza pandemic in 41 years had occurred. This 2009 pandemic H1N1 influenza virus has now spread worldwide, with confirmed cases of pandemic H1N1 virus infection reported in more than 100 countries in all 6 WHO regions[, which] has led to the need to add to the existing guidance on the use of antivirals.”

The new recommendations highlight oseltamivir and zanamivir, which are neuraminidase inhibitors, and amantadine and rimantadine, which are M2 inhibitors. Suggestions are also provided regarding the use of some other potential pharmacological treatments, such as ribavirin, interferons, immunoglobulins, and corticosteroids.

Management of patients with pandemic influenza (H1N1) 2009 virus infection is the primary focus of the statement, although it also includes guidance regarding the use of the antivirals for treatment of other seasonal influenza virus strains, as well as for infections resulting from novel influenza A virus strains.

The guidelines urge country and local public health authorities to issue local recommendations for clinicians periodically, based on epidemiological and antiviral susceptibility data on the locally circulating influenza strains. As the prevalence and severity of the current pandemic evolves, WHO anticipates that additional data will be forthcoming that may require revision of the current recommendations. WHO therefore plans to review the guidance no later than September 2009 to determine whether modifications to the recommendations are needed.

Recommendations for Antiviral Treatment of H1N1

For patients with confirmed or strongly suspected infection with influenza pandemic (H1N1) 2009, when antiviral medications for influenza are available, specific recommendations regarding use of antivirals for treatment of pandemic (H1N1) 2009 influenza virus infection are as follows:

* Oseltamivir should be prescribed, and treatment started as soon as possible, for patients with severe or progressive clinical illness (strong recommendation, low-quality evidence). Depending on clinical response, higher doses of up to 150 mg twice daily and longer duration of treatment may be indicated. This recommendation is intended for all patient groups, including pregnant women, neonates, and children younger than 5 years of age.
* Zanamivir is indicated for patients with severe or progressive clinical illness when oseltamivir is not available or not possible to use, or when the virus is resistant to oseltamivir but known or likely to be susceptible to zanamivir (strong recommendation, very low-quality evidence).
* Antiviral treatment is not required in patients not in at-risk groups who have uncomplicated illness caused by confirmed or strongly suspected influenza virus infection (weak recommendation, low-quality evidence). Patients considered to be at risk are infants and children younger than 5 years of age; adults older than 65 years of age; nursing home residents; pregnant women; patients with chronic comorbid disease including cardiovascular, respiratory, or liver disease and diabetes; and immunosuppressed patients because of malignancy, HIV infection, or other diseases.
* Oseltamivir or zanamivir treatment should be started as soon as possible after the onset of illness in patients in at-risk groups who have uncomplicated illness caused by influenza virus infection (strong recommendation, very low-quality evidence).

Recommendations for Chemoprophylaxis of H1N1

Specific recommendations regarding the use of antivirals for chemoprophylaxis of pandemic (H1N1) 2009 influenza virus infection are as follows:

* When risk for human-to-human transmission of influenza is high or low, and the probability of complications of infection is high, either because of the influenza strain or because of the baseline risk of the exposed group, use of oseltamivir or zanamivir may be considered as postexposure chemoprophylaxis for the affected community or group, for individuals in at-risk groups, or for healthcare workers (weak recommendation, moderate-quality evidence).
* Individuals in at-risk groups or healthcare personnel do not need to be offered antiviral chemoprophylaxis if the likelihood of complications of infection is low. This recommendation should be applied independent of risk for human-to-human transmission (weak recommendation, low-quality evidence).

For treatment of mild to moderate uncomplicated clinical presentation of infection with multiple cocirculating influenza A subtypes or viruses with different antiviral susceptibilities, patients in at-risk groups should be treated with zanamivir or oseltamivir plus M2 inhibitor (noting that amantadine should not be used in pregnant women). Otherwise-healthy patients with this presentation need not be treated.

When the clinical presentation of infection with multiple cocirculating influenza A subtypes or viruses with different antiviral susceptibilities is severe or progressive, all patients should be treated with oseltamivir plus M2 inhibitor, or zanamivir.

For treatment of mild to moderate uncomplicated clinical presentation of infection with sporadic zoonotic influenza A viruses including H5N1, the at-risk population should be treated with oseltamivir or zanamivir, and the otherwise-healthy population with oseltamivir. All patients, regardless of risk status, with severe or progressive presentation of infection with sporadic zoonotic influenza A viruses including H5N1 should be treated with oseltamivir plus an M2 inhibitor.

WHO Rapid Advice Guidelines on Pharmacological Management of Influenza Virus. Published online August 20, 2009.

Clinical Context

H1N1 influenza infection transmitted person to person was first detected by WHO in April 2009. Although the first cases were limited to Mexico and the United States, subsequent spread overseas resulted in WHO declaring on June 11, 2009, the first influenza pandemic to occur in 41 years.

Cases of pandemic H1N1 virus infection have now been confirmed in more than 100 countries in all 6 WHO regions, mandating updated recommendations on the use of antivirals for infections caused by new strains of pandemic (A)H1N1 virus. The present WHO guidelines also address antiviral use in seasonal influenza and in infections caused by other novel influenza A viruses, but they do not change existing guidelines on pharmacological management of humans infected with H5N1 virus.


Study Highlights

* When antiviral medications for influenza are available, patients with confirmed or strongly suspected infection with influenza pandemic (H1N1) 2009 should be treated as follows:
o All patient groups, including pregnant women, neonates, and young children younger than 5 years, with severe or progressive clinical illness should be treated as soon as possible with oseltamivir (strong recommendation, low-quality evidence).
+ Higher doses up to 150 mg twice daily and longer duration of treatment may be needed, depending on clinical response.
o Patients with severe or progressive clinical illness should receive zanamivir when oseltamivir is not available or not possible to use, or when the virus is resistant to oseltamivir but known or likely to be susceptible to zanamivir (strong recommendation, very low-quality evidence).
o Patients considered to be “at risk” are infants and children younger than 5 years, adults older than 65 years, nursing home residents, pregnant women, patients with chronic comorbidities (cardiovascular, respiratory or liver disease, and diabetes), and immunosuppressed patients as a result of malignant disease, HIV infection, or other diseases.
o Patients not in “at-risk” groups with uncomplicated illness because of confirmed or strongly suspected H1N1 infection may not need antiviral treatment (weak recommendation, low-quality evidence).
o Patients in “at-risk” groups with uncomplicated illness because of confirmed or strongly suspected H1N1 infection should be started with oseltamivir or zanamivir treatment as soon as possible after illness onset (strong recommendation, very low-quality evidence).
* Specific recommendations regarding use of antivirals for chemoprophylaxis of pandemic (H1N1) 2009 influenza virus infection are as follows:
o Oseltamivir or zanamivir may be used postexposure as chemoprophylaxis when risk for human-to-human transmission of influenza is high or low, and risk for complications of infection is high, either because of the influenza strain or because of the baseline risk for the exposed group:
+ In this setting, oseltamivir or zanamivir may be used in the affected community or group, in individuals in “at-risk” groups, or in healthcare workers (weak recommendation, moderate-quality evidence).
o If the risk for complications of infection is low, individuals in “at-risk” groups or healthcare personnel may not need antiviral chemoprophylaxis, independent of risk for human-to-human transmission (weak recommendation, low-quality evidence).

Clinical Implications

* Patients with confirmed or strongly suspected infection with influenza pandemic (H1N1) 2009 should be treated as soon as possible with oseltamivir if they have severe or progressive clinical illness, when the drug is available, and when the virus is not resistant.
* Oseltamivir or zanamivir may be used postexposure as chemoprophylaxis when the risk for human-to-human transmission of influenza is high or low, and risk for complications of infection is high, either because of the influenza strain or because of the baseline risk for the exposed group.

Personal digital assistant

A personal digital assistant (PDA) is a handheld computer, also known as a palmtop computer. Newer PDAs commonly have color screens and audio capabilities, enabling them to be used as mobile phones (smartphones), web browsers, or portable media players. Many PDAs can access the Internet, intranets or extranets via Wi-Fi, or Wireless Wide Area Networks (WWANs). Many PDAs employ touchscreen technology.

The first PDA is considered to be the Casio PF-15115-36 released in May 1983. GO Corp. was also pioneering in the field. The term was first used on January 7, 1992 by Apple Computer CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevada, referring to the Apple Newton. In 1996 Nokia introduced the first mobile phone with full PDA functionality, the 9000 Communicator, which has since grown to become the world’s best-selling PDA and which spawned a category of phones called the smartphone. The only function it does not have is that it is unable to record videos. Today the vast majority of all PDAs are smartphones, selling over 150 million units while non-phone (“stand-alone”) PDAs sell only about 3 million units per year. The RIM BlackBerry, the Apple iPhone and the Nokia N-Series are typical smartphones.

Typical features

Currently, a typical PDA has a touch screen for entering data, a memory card slot for data storage and at least one of the following for connectivity: IrDA, Bluetooth and/or WiFi. However, many PDAs (typically those used primarily as telephones) may not have a touch screen, using softkeys, a directional pad and either the numeric keypad or a thumb keyboard for input.

Software typically required to be a PDA includes an appointment calendar, a to-do list, an address book for contacts and some sort of note program. Connected PDAs also typically include E-mail and Web support.

Touch screen

Many of the original PDAs, such as the Apple Newton and Palm Pilot, featured touchscreen for user interaction, having only a few buttons usually reserved for shortcuts to often used programs. Touch screen PDAs, including Windows Mobile devices, usually have a detachable stylus that can be used on the touch screen. Interaction is then done by tapping the screen to activate buttons or menu choices, and dragging the stylus to, for example, highlight. Text input is usually done in one of four ways:

* Using a virtual keyboard, where a keyboard is shown on the touch screen. Input is done by tapping letters on the screen.
* Using external keyboard or chorded keyboard connected by USB, IR or Bluetooth.
* Using letter or word recognition, where letters or words are written on the touch screen, and then “translated” to letters in the currently activated text field. Despite rigorous research and development projects, end-users experience mixed results with this input method, with some finding it frustrating and inaccurate, while others are satisfied with the quality.[1] Recognition and computation of handwritten horizontal and vertical formulas such as “1 + 2 =” was also under development.
* Stroke recognition (one Palm implementation is called Graffiti). In this system a predefined set of strokes represents the various characters used in input. The user learns to draw these strokes on the screen or in an input area. The strokes are often simplified character shapes to make them easier for the device to recognize.

PDAs for business use, including the BlackBerry and Palm Treo, have full keyboards and scroll wheels or thumb wheels to facilitate data entry and navigation, in addition to supporting touch-screen input. There are also full-size foldable keyboards available that plug directly, or use wireless technology to interface with the PDA and allow for normal typing. BlackBerry has additional functionality, such as push-based email and applications.

Newer PDAs, such as the Apple iPhone, iPod Touch and Palm Pre include new user interfaces using other means of input. The iPhone and iPod touch uses a technology called Multi-touch.

Memory cards

Although many early PDAs did not have memory card slots now most have either an SD (Secure Digital) and/or a Compact Flash slot. Although originally designed for memory, SDIO and Compact Flash cards are available for such things as Wi-Fi and Webcams. Some PDAs also have a USB port, mainly for USB flash drives. Some PDAs are now compatible with micro SD cards, which are physically much smaller than standard SD cards.

[edit] Wired connectivity

While many earlier PDAs connected via serial ports or other proprietary format, many today connect via USB cable. This served primarily to connect to a computer, and few, if any PDAs were able to connect to each other out of the box using cables, as USB requires one machine to act as a host – functionality which was not often planned. Some PDAs were able to connect to the internet, either by means of one of these cables, or by using an extension card with an ethernet port/RJ-45 adaptor.

Wireless connectivity

Most modern PDAs have Bluetooth wireless connectivity, an increasingly popular tool for mobile devices. It can be used to connect keyboards, headsets, GPS and many other accessories, as well as sending files between PDAs. Many mid-range and superior PDAs have Wi-Fi/WLAN/802.11-connectivity, used for connecting to Wi-Fi hotspots or wireless networks. Older PDAs predominantly have an IrDA (infrared) port; however fewer current models have the technology, as it is slowly being phased out due to support for Bluetooth and Wi-Fi. IrDA allows communication between two PDAs: a PDA and any device with an IrDA port or adapter. Most universal PDA keyboards use infrared technology because many older PDAs have it, and infrared technology is low-cost and has the advantage of being permitted aboard aircraft.

Synchronization

An important function of PDAs is synchronizing data with a PC. This allows up-to-date contact information stored on software such as Microsoft Outlook or ACT! to update the database on the PDA. The data synchronization ensures that the PDA has an accurate list of contacts, appointments and e-mail, allowing users to access the same information on the PDA as the host computer.

The synchronizing also prevents the loss of information stored on the device in case it is lost, stolen, or destroyed. Another advantage is that data input is usually a lot quicker on a PC, since text input via a touch screen is still not quite optimal. Transferring data to a PDA via the computer is therefore a lot quicker than having to manually input all data on the handheld device.

Most PDAs come with the ability to synchronize to a PC. This is done through synchronization software provided with the handheld, such as HotSync Manager, which comes with Palm OS handhelds, Microsoft ActiveSync for Windows XP and older operating systems, or Windows Mobile Device Center for Windows Vista, both of which sync with Windows Mobile or Pocket PC devices.

These programs allow the PDA to be synchronized with a Personal information manager. This personal information manager may be an outside program or a proprietary program. For example, the BlackBerry PDA comes with the Desktop Manager program which can synchronize to both Microsoft Outlook and ACT!. Other PDAs come only with their own proprietary software. For example, some early Palm OS PDAs came only with Palm Desktop while later Palms such as the Treo 650 has the built-in ability to sync to Palm Desktop and/or Microsoft Outlook, while Microsoft’s ActiveSync and Windows Mobile Device Center only synchronize with Microsoft Outlook or a Microsoft Exchange server.

Third-party synchronization software is also available for many PDAs from companies like Intellisync and CompanionLink. This software synchronizes these handhelds to other personal information managers which are not supported by the PDA manufacturers, such as GoldMine and IBM Lotus Notes.

PDAs are used to store information that can be accessed at any time and anywhere.

Automobile navigation

Many PDAs are used in car kits and are fitted with differential Global Positioning System (GPS) receivers to provide realtime automobile navigation. PDAs are increasingly being fitted as standard on new cars.

Many systems can also display traffic conditions, dynamic routing and roadside mobile radar guns. Popular software in Europe and in America for this functionality are TomTom, Garmin, iGO etc. showing road conditions and 2D or 3D environments.

Ruggedized PDAs

For many years businesses and government organizations have relied upon rugged PDAs also known as enterprise digital assistants (EDAs) for mobile data applications. Typical applications include supply chain management in warehouses, package delivery, route accounting, medical treatment and record keeping in hospitals, facilities maintenance and management, parking enforcement, access control and security, capital asset maintenance, meter reading by utilities, and “wireless waitress” applications in restaurants and hospitality venues. A common feature of EDAs are the integration of Data Capture devices like Bar Code, RFID and Smart Card Readers.

Medical and scientific uses

In medicine, PDAs have been shown to aid diagnosis and drug selection and some studies have concluded that their use by patients to record symptoms improves the effectiveness of communication with hospitals during follow-up. A range of resources have been developed to cater for the demand from the medical profession which supply drug databases, treatment information and relevant news in formats specific to mobile devices and services such as AvantGo translate medical journals into readable formats and provide updates from journals. WardWatch organizes medical records to remind doctors making ward rounds of information such as the treatment regimens of patients and programs. Finally, Pendragon and Syware provide tools for conducting research with mobile devices, and connecting to a central server allowing the user to enter data into a centralized database using their PDA. Additionally, Microsoft Visual Studio and Sun Java provide programming tools for developing survey instruments on the handheld. These development tools allow for integration with SQL databases that are stored on the handheld and can be synchronized with a desktop/server based database.

Recently the development of Sensor Web technology has led to discussion of using wearable bodily sensors to monitor ongoing conditions like diabetes and epilepsy and alerting medical staff or the patient themselves to the treatment required via communication between the web and PDAs…..

Educational uses

As mobile technology becomes more common, it is increasingly being used as a learning tool. Some educational institutions have integrated PDAs into their teaching practices (MLearning). .

PDAs and handheld devices are commonly allowed in the classroom for digital note taking. Students can spell-check, modify, and amend their class notes or e-notes. Some educators distribute course material through the use of the internet connectivity or infrared file sharing functions of the PDA. Textbook publishers have begun to release e-books, or electronic textbooks, which can be uploaded directly to a PDA, reducing the number of textbooks students must carry.

Software companies have developed programs to meet the instructional needs of educational institutions such as dictionaries, thesauri, word processing software, encyclopedias and digital planning lessons.

The increase in mobility of PDAs have caused some problems for school boards and educational institutions. School boards are now concerned about students utilizing the internet connectivity to share test answers or to gossip during class time. Many school boards have modernized their computer policies to address these new concerns. Software companies such as Scantron Corp. have now created programs for distributing digital quizzes which disables the infrared function on PDAs, which eliminates the possibility of information sharing between students during the examination. Many colleges, however, encourage the use of PDAs, and some business, nursing, and physician assistant (PA) programs even require them.


Sporting uses

PDAs are used by glider pilots for pre-flight planning and to assist navigation in cross-country competitions. They are linked to a GPS to produce moving-map displays showing the tracks to turn-points, airspace hazards and other tactical information.

PDAs may also be used by music enthusiasts. They can be used to play a variety of file formats (unlike most MP3 Players) during physical exercise (e.g. running), unlike certain larger devices such as laptops.

PDAs can be used by road rally enthusiasts. PDA software can be used for calculating distance, speed, time, and GPS navigation as well as unassisted navigation.

PDA for people with disabilities

PDAs offer varying degrees of accessibility for people with differing abilities, based on the particular device and service. People with vision, hearing, mobility, and speech impairments may be able to use PDAs on a limited basis, and this may be enhanced by the addition of accessibility software (e.g. speech recognition for verbal input instead of manual input). Universal design is relevant to PDAs as well as other technology, and a viable solution for many user-access issues, though it has yet to be consistently integrated into the design of popular consumer PDA devices.

PDAs have recently become quite useful in the Traumatic brain injury/Posttraumatic stress disorder population, especially seen in troops returning home from Operation Iraqi Freedom(OIF)/Operation Enduring Freedom(OEF). PDAs address memory issues and help these men and women out with daily life organization and reminders. As of quite recently, the Department of Veterans’ Affairs (VA) has begun issuing thousands of PDAs to troops who present the need for them. Occupational therapists have taken on a crucial role within this population helping these veterans return to the normality of life they once had.

Popular consumer PDAs

* E-TEN
* Abacus PDA Watch
* Acer N Series
* AlphaSmart
* Audiovox (Sprint) PPC Series
* Amida Simputer
* Encore Simputer
* BlackBerry
* Fujitsu Siemens Computers Loox
* HP iPAQ
* HTC Corporation (Dopod, Qtek)’s series of Windows Mobile PDA/phones (HTC)
* I-mate
* Nokia E Series
* Palm, Inc. (Tungsten E2, TX, Treo, Zire Handheld, and Pre)
* PocketMail (email PDA with inbuilt acoustic coupler)
* Psion – obsolete
* Sharp Wizard and Sharp Zaurus – obsolete
* T-Mobile Dash and T-Mobile Wing
* Sidekick
* Royal
* Motorola Rokr E6
* MotoRokr E8
* HTC, especially the HTC P3470 aka Pharos
* SonyEricsson P-series
* Apple Inc.’s iPhone & iPod Touch

References
1. HWR accuracy:
* See comments in Wired’s Apple Newton Just Won’t Drop (4 yrs later)
* See text under suck it suck it”Handwriting Recognition” in Pen Computing’s First Look at Newton OS 2.0
* See “Opportunity Squandered” in Pen Computing’s Why did Apple kill the Newton?
* See comments under “Software” in MacTech’s MessagePad 2000 reviewwoooooo
* Comments by Pen Computing’s editor
* See user testing results discussed in part 6 of this A.I. Magazine article on Newton HWR
* MessagePad 2000 review at Small Dog Electronics
* See comments under “Note-taking” in MessagePad 2000 review at “The History and Macintosh Society”
* What’s Right With The Newton: HWR