Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_160_библиотеки_им_акад_М_И_Перельмана
.pdf
OBSTETRIC ANESTHESIA 293
28. What options are available for postoperative pain control after cesarean
delivery?
This depends on the anesthetic technique used for the surgical procedure.
• If spinal anesthesia was used, preservative-free morphine is typically included with the local
anesthetic. Intrathecal morphine (0.15 to 0.25 mg) provides analgesia for 16 to 24 hours. Side
effects include pruritus, nausea and vomiting, and rarely respiratory depression. Respiratory
depression has a higher risk of occurring if the patient receives supplemental IV opioids or
sedatives.
• If epidural anesthesia was used, 2.5 to 5 mg of morphine administered into the epidural space
provides 16 to 24 hours of analgesia. Risks are the same as for intrathecal morphine. Occasion-
ally, epidural infusion of low concentrations of local anesthetic and an opioid can be extended into
the postoperative period and the patient given a controller device to augment a basal infusion rate
(PCEA).
• If general anesthesia was used, the patient can be offered postoperative IV PCA. With PCA, a
pump allows for the continuous infusion of an opioid and for the patient to self-administer boluses
when desired. Although programmed limits prevent overdosing, continuous monitoring of ventila-
tion and sedation level is required.
• Ultrasound-guided transverse abdominal plane (TAP) block is an alternative method for
postoperative pain control. With this method, local anesthetic is deposited bilaterally between
the internal oblique and transverse abdominis muscles. This can help control pain in the
abdominal wall, but not the uterus. TAP is usually supplemented with IV pain medications such
as ketorolac (a nonsteroidal antiinflammatory drug [NSAID]). Overall, the analgesic effect is
inferior to that of intrathecal morphine, but TAP is associated with fewer opioid-related side
effects. A TAP block may be a reasonable alternative when opioids are contraindicated or not
appropriate.
29. What are the basic steps in the resuscitation (Advanced Cardiac Life Support
[ACLS]) of an obstetric patient?
Cardiac arrest during pregnancy occurs in less than 1 in 20,000 women. Leading causes are amniotic
fluid embolism (AFE), hemorrhage, preexisting heart disease, trauma, sepsis, and iatrogenic causes
(e.g., local anesthetic toxicity, high spinal, allergic reactions). ACLS protocols are applicable to the
pregnant patient, but with additional considerations. In 2014 the Society of Obstetric Anesthesia
and Perinatology issued a consensus statement that addressed resuscitation efforts in the pregnant
patient to optimize maternal and neonatal outcomes:
• High-quality chest compressions should be performed with hands placed higher on the sternum.
This is secondary to elevation of the diaphragm associated with pregnancy.
• Manual uterine displacement to the left is vital to help achieve adequate venous return to the heart.
Tilting the patient may compromise the adequacy of chest compressions.
• Treat reversible causes (e.g., local anesthetic toxicity, transfuse).
• If no return of spontaneous circulation occurs within 4 minutes and the fetus is viable, a peri-
mortem cesarean delivery should be performed. The best chance for fetal survival is if delivery is
achieved within 5 minutes of the onset of cardiac arrest.
KEY POINTS: OBSTETRIC ANESTHESIA
1. Pain during the first stage of labor is primarily visceral; it results from cervical dilation and uterine
contractions and is transmitted by afferents originating in the T10 to L1 segments of the spinal
cord.
2. Pain during the second stage of labor is both visceral and somatic; it is transmitted by the same
afferents as in the first stage, in addition to afferents from S2 to S4.
3. Lumbar epidural analgesia is the most popular method for pain relief during labor. It is effective for
both the first and second stages.
4. Although epidural analgesia is associated with slight prolongation of the second stage and an
increased rate of operative vaginal delivery, it does not increase the risk of cesarean delivery or
neonatal depression.
5. Spinal anesthesia is the most common method of anesthesia for cesarean delivery; general anes-
thesia has a higher rate of maternal morbidity.
https://t.me/med1917
294 LABOR, DELIVERY, AND POSTPARTUM
BiBliography
1. Afolabi BB, Lesi FE. Regional versus general anesthesia for cesarean section. Cochrane Database Syst Rev. 2012;10.
CD004350.
2. American College of Obstetricians and Gynecologists. Pain relief during labor. ACOG committee opinion no. 295.
Obstet Gynecol. 2004;104:213.
3. Bateman BT, Berman MF, Riley LE, Leffert LR. The epidemiology of postpartum hemorrhage in a large, nationwide
sample of deliveries. Anesth Analg. 2010;110:1368–1373.
4. Baysinger C. Nitrous Oxide for Labor Analgesia. Available at: www.asahq.org/resources/resources-from-ASA-committee/
nitrous-oxide
5. Bucklin BA, Hawkins JL, Anderson JR, Ullrich FA. Obstetric anesthesia workforce survey: twenty-year update.
Anesthesiology. 2005;103:645–653.
6. California Maternal Quality Care Collaborative. OB Hemorrhage Toolkit V 2.0. Available at:
https://www.cmqcc.org/ob_hemorrhage. Accessed November 10, 2015.
7. Cambic C, Wong C. Labour analgesia and obstetric outcomes. Br J Anaesth. 2010;105:i50–i60.
8. D’Angelo R, Smiley RM, Riley ET, Segal S. Serious complications related to obstetric anesthesia: the serious
complication repository project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology. 2014;120:
1505–1512.
9. Dutton RP, Lee LA, Stephens LS, Posner KL, Davies JM, Domino KB. Massive hemorrhage: a report from the
Anesthesia Closed Claims Project. Anesthesiology. 2014;121:450–468.
10. Hawkins JL, Chang J, Palmer SK, Gibbs CP, Callaghan W. Anesthesia-related maternal mortality in the United
States:1979-2002. Obstet Gynecol. 2011;117:69–74.
11. Kinsella SM, Lohmann G. Supine hypotensive syndrome. Obstet Gynecol. 1994;83:774–788.
12. Lang AJ, Sorrell JT, Rogers CS, Lebeck MM. Anxiety sensitivity as a predictor of labor pain. Eur J Pain. 2006;10:
263–270.
13. Likis FE, Andrews JC, Collins MR, et al. Nitrous oxide for the management of labor pain: a systematic review. Anesth
Analg. 2014;118:153–167.
14. Lipman S, Cohen S, Einav S, et al. The Society for Obstetric Anesthesia and Perinatology consensus statement on the
management of cardiac arrest in pregnancy. Anesth Analg. 2014;118:1003–1016.
15. Loane H, Preston R, Douglas MJ, Massey S. A randomized controlled trial comparing intrathecal morphine with
transversus abdominis plane block for post cesarean delivery analgesia. Int J Obstet Anesth. 2012;21:112–118.
16. Melzack R. The myth of painless childbirth (the John J. Bonica lecture). Pain. 1984;19:321–337.
17. Sachs A, Smiley R. Post-dural puncture headache: the worst common complication in obstetric anesthesia. Semin
Perinatol. 2014;38:386–394.
18. Segal S. Labor epidural analgesia and maternal fever. Anesth Analg. 2010;111:1467–1475.
19. Somuah M, Smyth RMD, Howell CJ. Epidural versus non-epidural or no analgesia in labour. Cochrane Database Syst
Rev. 2011;12. CD000331.
20. Stocki D, Matot I, Einav S, et al. A Randomized Controlled Trial of the Efficacy and Respiratory Effects of Patient-
Controlled Intravenous Remifentanil Analgesia and Patient-Controlled Epidural Analgesia in Laboring Women. Anesth
& Analg. 2014;118:589–597.
21. Ullman R, Smith LA, Burns E, Mori R, Dowswell T. Parenteral opioids for maternal pain relief in labor. Cochrane
Database Syst Rev. 2010;9. CD007396.
22. Wali A, Suresh M. Maternal morbidity, mortality, and risk assessment. Anesthesiol Clin. 2008;26:197–230.
23. Zakowski MI. Complications associated with regional anesthesia in the obstetric patient. Semin Perinatol.
2002;26:154–168.
24. Zakowski MI, Geller A. The placenta: anatomy, physiology, and transfer of drugs. In: Chestnut DH, Wong CA, Tsen LC,
et al., eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 5th ed. Philadelphia: Saunders; 2014.
https://t.me/med1917
295
1. How is preterm labor defined?
Preterm labor is defined as regular uterine contractions, with or without pain, accompanied by progressive
cervical dilation or effacement and occurring between 20 0/7 weeks and 36 6/7 weeks of gestation.
2. What causes preterm labor?
In the majority of cases, the cause of preterm labor is unknown. Most experts agree that infection
(urogenital or systemic) may be largest contributor.
3. What are the risk factors associated with preterm labor?
The strongest risk factor is a previous preterm birth, and a history of a previous preterm delivery
increases the risk of subsequent preterm birth by up to twofold. Other risk factors are listed in Box 65-1.
4. What is the incidence of preterm birth?
Although incidence varies with the population studied, preterm birth complicates approximately 12%
of all live births in the United States; it is the leading cause of neonatal mortality.
5. What are the consequences of preterm birth?
Prematurity results in increased risk of neonatal morbidity and death, with the majority of neonatal
deaths occurring in infants born before 28 weeks of gestation (Fig. 65-1). Major neonatal complica-
tions include the following:
• Neonatal respiratory distress syndrome (RDS)
• Persistent pulmonary hypertension
CHAPTER 65
PRETERM LABOR AND
PRETERM PREMATURE
RUPTURE OF MEMBRANES
Enid T. Kuo, MD
• Previous preterm delivery
• Multiple gestation
• Preterm premature rupture of membranes
• Polyhydramnios
• Placental abruption
• Placenta previa
• Uterine anomalies
• Previous cervical surgical procedures
• Diethylstilbestrol (DES) exposure
• Congenital anomalies or aneuploidy
• Fetal demise
• Extremes of maternal age (<18 or >35 years)
• Low socioeconomic status
• Smoking
• Substance abuse
• Short interpregnancy interval
• Poor nutritional status or low body mass index
• Poor pregnancy weight gain
• Infections (e.g., chorioamnionitis, pyelonephritis, other serious systemic infection)
Box 65-1. Risk Factors for Preterm Labor
https://t.me/med1917
296 LABOR, DELIVERY, AND POSTPARTUM
• Bronchopulmonary dysplasia (BPS)
• Intraventricular hemorrhage (IVH)
• Periventricular leukomalacia (PVL)
• Necrotizing enterocolitis (NEC)
6. What are the rates of survival for preterm infants?
Survival estimates by gestational age are as follows:
• More than 50% at 24 weeks
• 68% at 25 weeks
• More than 75% at 26 to 28 weeks
• More than 90% at 28 weeks and beyond
These estimates are for mortality alone; although most infants born after 28 weeks survive, only
approximately 80% will be free of long-term morbidity. Survival is also affected by accessibility
to tertiary neonatal support, as well as the level of provider expertise in neonatal resuscitation
and subsequent care. Data suggest that birth weight may correlate better with morbidity and
mortality (Table 65-1). An even more accurate estimate can be obtained using the National
Institute of Child Health and Human Development (NICHD) website, which takes into account
gestational age, birth weight (estimated), sex, and whether antenatal steroids were given:
www.nichd.nih.gov/about/org/der/branches/ppb/programs/epbo/Pages/epbo_case.aspx.
60
50
40
30
20
10
70
80
90
0
100
383632 3428262422 30
Percent
Gestation (weeks)
Respiratory distress
Sepsis
Intraventricular hemorrhage
Necrotizing enterocolitis
Figure 65-1. Neonatal morbidity by gestational age at birth. Results of a community-based evaluation of 8523 deliv-
eries, 1997 to 1998, Shelby County, Tennessee. Curves are smoothed by a two-point average. (From Mercer BM. Preterm
premature rupture of membranes. Obstet Gynecol. 2003;101:178.)
Table 65-1. Survival Estimates Based on Birth Weight
WEIGHT (g) SURVIVED SURVIVED WITHOUT MORBIDITY
501-750 55% 35%
751-1000 88% 57%
1001-1250 94% 78%
1251-1500 96% 89%
https://t.me/med1917
PRETERM LABOR AND PRETERM PREMATURE RUPTURE OF MEMBRANES 297
7. What are common symptoms of preterm labor?
• Regular uterine contractions (with or without pain)
• Pelvic pressure
• Lower back pain, typically described as dull and constant
• Abdominal cramping
• Vaginal spotting or bleeding
8. How should a patient with possible preterm labor be evaluated?
A careful history should be taken and potential risk factors identified. Physical examination should
include a pelvic examination to collect cultures for group B streptococcus (GBS), gonorrhea, and
Chlamydia; if concern exists for ruptured fetal membranes, this should be ruled out first (see question 24).
Cervical dilation and effacement should be assessed, and laboratory studies ordered (see question 9).
Continuous fetal monitoring with tocometry should be performed in pregnancies of more than 24 weeks
of gestation.
9. What laboratory studies should be ordered?
• Complete blood count
• Urine analysis and culture
• Cultures for GBS, gonorrhea, and Chlamydia
• Urine toxicology screen if indicated
• Fetal fibronectin (fFN), which can also help to stratify risk (see question 12)
10. What imaging studies should be performed?
• Transabdominal ultrasound for fetal weight and presentation
• Transvaginal ultrasound for cervical length
11. How is cervical length measured, and what is considered normal?
After a patient has emptied her bladder, a transvaginal probe is placed in the anterior fornix of the
vagina, and the distance of the closed portion of the cervix is measured (Fig. 65-2). In symptomatic
women, cervical length is used to assess a patient’s risk of preterm delivery within the next 7 days
and help direct management.
• A length less than 20 mm indicates an increased risk of preterm delivery; these patients are
generally admitted for closer monitoring and administration of antenatal steroids.
• A length of 30 mm or greater indicates a low risk of preterm delivery.
• A length of 20 to 29 mm is an indeterminate range. fFN can be used to provide additional risk
assessment (see question 12).
A
B
C
D
Figure 65-2. Transvaginal ultrasound and sagittal long-axis view of the endocervical canal. The cervical length is
measured from the internal os to the external os along the endocervical canal. A, Internal os. B, External os. C, Amniotic
fluid. D, Ultrasound probe. (From Bahtiyar MO, Nayeri UA, Shaffer WK. Atlas of selected normal images. In: Copel JA,
D’Alton ME, Gratacos E, et al, eds. Obstetric Imaging. Philadelphia: Saunders; 2012:1-12.)
https://t.me/med1917
298 LABOR, DELIVERY, AND POSTPARTUM
12. What is fFN, and how is it used in patients with symptoms of preterm labor?
fFN is a large glycoprotein found at the interface between the chorion and uterine decidua. It
promotes cellular adhesion and is released into the extracellular matrix when the interface between
the chorion and decidua is disrupted. A negative test result is fairly reassuring that delivery will not
occur in the next 7 to 14 days, with a negative predictive value near 99%. The positive predictive
value, however, is only 30%. fFN is valid between 22 and 34 weeks of gestation and is typically
used in combination with transvaginal cervical length measurement. However, it must be col-
lected before any other swabs, cultures, or examination because results are affected by cervical
manipulation, semen, blood, and lubricant. It has not been shown to be helpful as a screening tool
in asymptomatic women.
13. How is preterm labor treated?
At present, no medication has been proven effective in treating preterm labor ; medical interventions
are directed at decreasing morbidity and mortality for the infant.
• Antenatal corticosteroids are the most beneficial in improving neonatal outcome and should be
given for all cases between 24 and 34 weeks of gestation. These drugs have been demonstrated
to decrease the risk of RDS, IVH, NEC, and neonatal death. Two different regimens are using, both
given intramuscularly: two 12-mg doses of betamethasone 24 hours apart, or four 6-mg doses
of dexamethasone every 12 hours. Even a single dose has been shown to reduce morbidity and
mortality, so treatment should be initiated even if delivery is likely to occur in less than 24 hours.
Additional benefit may be derived from a repeat course (referred to as a “rescue” course) if more
than 2 weeks have passed and delivery is anticipated before 34 weeks; however, additional benefit
has not been demonstrated for accelerated rescue dosing or three or more courses. Weekly admin-
istration of corticosteroids has been associated with a reduction in head circumference and birth
weight and is not recommended.
• Magnesium sulfate has been shown to reduce the severity and overall risk of cerebral palsy
in surviving infants and is administered for neuroprotection when delivery is anticipated before
32 weeks of gestation. Several different regimens exist, and all are believed to be efficacious;
treatment for this purpose typically does not extend past 24 hours.
• Tocolytic therapy has not been shown to prolong pregnancy more than 48 hours and is generally
reserved for cases in which a brief delay in delivery would be beneficial, such as to allow for a full
course of antenatal corticosteroids. No evidence exists to support any direct favorable effects on
neonatal outcome from tocolysis alone.
• GBS prophylaxis is administered in the majority of cases of preterm labor; the only exception is if
the patient has had a negative GBS culture result within the past 5 weeks.
Strict bed rest has not been shown be beneficial and increases the risk of venous thromboembolism
(VTE). It is no longer recommended for the management of preterm labor.
14. What are common tocolytic agents, their mechanisms of action, and side
effects?
Terbutaline, a β-adrenergic agonist. Generally reserved for short-term tocolysis, it is given as
0.25 mg subcutaneously every 4 hours as needed. Total dosage is not to exceed 5 mg in 24 hours,
and treatment should not extend beyond 48 hours.
• Mechanism: It activates β-adrenergic receptors to increase adenyl cyclase and increases intracel-
lular cyclic adenosine monophosphate (cAMP). cAMP reduces intracellular calcium levels and
decreases sensitivity of the myosin-actin contractile unit to calcium.
• Side effects: hypotension, pulmonary edema, cardiac arrhythmias, chest pain, tachycardia,
myocardial ischemia, hyperglycemia, hypokalemia, and glucose intolerance
Nifedipine, a calcium channel blocker. It is given orally as a 30-mg load, then 10 to 30 mg orally
every 3 to 6 hours.
• Mechanism: It interferes with influx of calcium through voltage-gated calcium channels.
• Side effects: flushing, headache, maternal hypotension; increased risk of respiratory depression
with concomitant use of magnesium sulfate
Magnesium sulfate. It is given as a 4- to 6-g intravenous bolus over 20 minutes and then continued
at 2 to 4 g/hour.
• Mechanism: It has an unclear mechanism of action but likely competes with calcium at voltage-
gated calcium channels in smooth muscle.
• Side effects: hypotension, flushing, lethargy, pulmonary edema, loss of deep tendon reflexes (DTR),
and respiratory and cardiac depression or arrest
https://t.me/med1917
PRETERM LABOR AND PRETERM PREMATURE RUPTURE OF MEMBRANES 299
Indomethacin, a prostaglandin synthetase inhibitor. Given orally 25 to 50 mg every 8 hours, it is
reserved for gestations of less than 32 weeks because of potential in utero closure of the ductus
arteriosus.
• Mechanism: It competes with arachidonic acid for cyclooxygenase (COX), thus inhibiting
prostaglandin synthesis.
• Side effects: oligohydramnios, gastric irritation, and platelet dysfunction
15. Do any contraindications to tocolysis exist?
Yes. Tocolysis is contraindicated in any instance when continuing the pregnancy would cause undue
risk to the fetus, mother, or both. Examples include chorioamnionitis, intrauterine fetal demise, placental
abruption, lethal fetal anomaly, preeclampsia with severe features or eclampsia (see Chapter 49), and
known intolerance to tocolytics.
16. Can preterm labor be prevented?
Spontaneous preterm birth cannot always be prevented, but interventions to reduce it are available.
These interventions are divided into two categories based on whether or not a patient has a history of
preterm birth.
• In women with a singleton pregnancy, no history of preterm birth, and short cervical length (defined
as ≤20 mm at <24 weeks of gestation), daily vaginal progesterone is recommended until 36 weeks
of gestation. It can be given as a 200-mg suppository or 90-mg gel and is usually taken at night.
• In women with a singleton pregnancy and earlier spontaneous preterm birth between 20 and
36 weeks of gestation, intramuscular 17α-hydroxyprogesterone caproate should be administered
weekly from 16 weeks to 36 weeks of gestation. Transvaginal ultrasound for cervical length
assessment should be performed every 1 to 2 weeks, and cerclage should be offered if a length
shorter than 25 mm is observed (Fig. 65-3) before 24 weeks of gestation.
17. What is premature rupture of membranes (PROM), and what is preterm PROM
(PPROM)?
PROM is defined as rupture of membranes before the onset of labor. PPROM is defined as rupture of
membranes before the onset of labor and before 37 weeks of gestation. The exact cause of PPROM is
often unknown, but it is thought to be secondary to an underlying process that weakens the amnion.
18. What is the incidence of PROM and PPROM?
In the United States, PROM occurs in 8% of term pregnancies, and PPROM occurs in 3% of all
pregnancies.
19. What are risk factors for PPROM?
• Previous history of PPROM
• Vaginal or cervical infection
• Cigarette smoking
• Substance abuse
• Cervical insufficiency
• Previous cervical surgical procedures
• Vaginal bleeding during pregnancy
• Polyhydramnios
• Long-term steroid use
• Connective tissue disease (e.g., Ehlers-Danlos syndrome)
• Amniocentesis (risk of PROM is 1%; iatrogenic rupture has a high chance of spontaneous “resealing”
of membranes and often carries a good prognosis in the absence of infection)
20. What are the major complications of PPROM?
In addition to fetal and neonatal infection, PPROM is associated with risks of prematurity (see question 5).
Maternal complications include placental abruption (2% to 5%), intraamniotic infection (15% to 25%),
and postpartum infection (15% to 20%). Cesarean delivery for nonvertex presentation and cord prolapse
also occur more commonly in cases of PPROM.
21. What organisms have been associated with intraamniotic infection in patients
with PPROM?
Although infections are typically polymicrobial, organisms cultured from amniotic fluid include GBS,
Escherichia coli, enterococci, Bacteroides species, Ureaplasma or Mycoplasma species, peptostrepto-
cocci, fusobacteria, and Gardnerella vaginalis.
https://t.me/med1917
300 LABOR, DELIVERY, AND POSTPARTUM
22. What is the significance of PPROM before pregnancy viability?
Rupture of fetal membranes before viability (<24 weeks of gestation) occurs in less than 1% of
pregnancies. Lung development relies largely on the presence of a normal amniotic fluid volume,
and pulmonary hypoplasia affects 10% to 20% of fetuses with PPROM before viability. Survival is far
greater after 22 weeks of gestation compared with rupture before this time (57.7% versus 14.4%,
respectively). Prolonged oligohydramnios can also result in Potter sequence, which is characterized
by abnormal facial characteristics and limb contractures.
23. What are common symptoms of PROM?
Patients typically complain of fluid leakage, either as a sudden, large-volume loss or as a small but
continuous flow. Contractions may or may not be present.
24. How should a patient with possible PPROM be evaluated?
Three key components of an evaluation for PPROM:
1. Visualization of amniotic fluid pooling in the vaginal vault or passing through the cervix
2. Using nitrazine paper to test the pH of vaginal fluid. The pH of amniotic fluid is generally 7.1 to 7.3,
which turns the paper from yellow to blue. Contaminants such as blood, semen, and occasionally
bacterial vaginosis may yield a false-positive result.
Singletons
No prior PTB Prior PTB
Routine
obstetric care
Vaginal
progesterone
c
CL ≤ 20 mm
CL ≥ 25 mmCL < 25 mm
CL > 20 mm
Cerclage;
continue 17P
Continue
17P
Single TVU CL
at 18-24 wks
a
17P
b
Serial TVU CL
at 16-23 6/7 wks
Figure 65-3. Algorithm for the clinical use of progesterone supplementation.
a
If transvaginal ultrasound (TVU)
cervical length (CL) screening is performed;
b
17α-hydroxyprogesterone caproate (17P) 250 mg intramuscularly every
week from 16 to 20 weeks to 36 weeks (
c
e.g., daily 200-mg suppository or 90-mg gel from the time of diagnosis of short
CL to 36 weeks). PTB, preterm birth. (From Society for Maternal-Fetal Medicine Publications Committee, with assistance
of Vincenzo Berghella. Progesterone and preterm birth prevention: translating clinical trials data into clinical practice. Am J
Obstet Gynecol. 2012;206:376-386.)
https://t.me/med1917
PRETERM LABOR AND PRETERM PREMATURE RUPTURE OF MEMBRANES 301
3. Assessment for ferning. Vaginal fluid is placed on a microscope slide and allowed to dry;
amniotic fluid has a classic arborization or “fernlike” pattern when examined under a
microscope.
A sterile speculum examination should be used during the evaluation, and cultures should be collected
to rule out any infection. Digital examinations are avoided because of the potential increased risk
of infection, and lubricants should be minimized or avoided because they are pH neutral and can
crystalize.
25. What other tests can be used to determine whether PPROM has occurred?
Transabdominal ultrasound to assess amniotic fluid volume may be helpful, although normal volume
does not necessarily rule out ruptured membranes. If a definitive diagnosis cannot be made and
determination of PPROM is needed for crucial management decisions, indigo carmine dye can be
injected into the amniotic cavity by using ultrasound guidance. A pad or tampon is then placed;
visualization of blue dye confirms membrane rupture. Methylene blue should be used for this purpose
because of the risk of fetal methemoglobinemia.
26. How is PPROM managed?
Patients with gestations of less than 34 weeks should receive antenatal corticosteroids, and those
with gestations of less than 32 weeks should receive magnesium sulfate for neuroprotection.
Latency antibiotics have been shown to prolong pregnancy and reduce maternal and neonatal
infections, and they are given in gestations of less than 34 weeks. The recommended regimen is
intravenous ampicillin (2 g every 6 hours) and erythromycin (250 mg every 6 hours) for 48 hours,
followed by oral amoxicillin (250 mg every 8 hours) and erythromycin base (333 mg every 8 hours)
for an additional 5 days. This antibiotic regimen also acts as GBS prophylaxis, although if the
patient begins laboring after the 7-day course of latency antibiotics has finished, GBS prophylaxis
should still be given.
27. Should tocolysis be considered for patients with PPROM?
Tocolytics are not recommended in the setting of PPROM with active preterm labor because of an
increased risk of chorioamnionitis.
28. What is the latency period, and how is it defined?
Latency refers to the interval between rupture of membranes and the onset of labor. It is inversely
correlated with the gestational age at time of membrane rupture. On average, at least half of patients
with PPROM will deliver within 1 week.
29. What are the recommendations for delivery in the setting of PPROM?
Indications for expeditious delivery are the same as in term patients and include intrauterine infection,
nonreassuring fetal status, placental abruption, suspicion of uterine rupture, and cord prolapse. In the
absence of an indication, patients can be managed expectantly and delivery planned for 34 0/7 weeks
of gestation or later. If PPROM occurs at a gestation of more than 34 weeks, it is actively managed
by inducing labor or delivery by cesarean section (if indicated; for more information on this topic, see
Chapter 63).
KEY POINTS: PRETERM LABOR AND PRETERM PREMATURE RUPTURE
OF MEMBRANES
1. Preterm labor is defined as cervical change with regular contractions between 20 and 36 6/7 weeks
of gestation.
2. Antenatal corticosteroids administered before 34 weeks of gestation significantly reduces the risk of
neonatal RDS, IVH, and NEC.
3. Magnesium sulfate for the purpose of fetal neuroprotection is administered in gestations of less
than 32 weeks when birth appears imminent.
4. PROM is the rupture of fetal membranes before the onset of labor. Rupture before 37 weeks of
gestation is PPROM.
5. Broad-spectrum antibiotics administered in cases of PPROM at less than 34 weeks of gestation
significantly reduce maternal and neonatal infectious morbidity.
https://t.me/med1917
302 LABOR, DELIVERY, AND POSTPARTUM
BiBliography
1. American College of Obstetricians and Gynecologists. Magnesium sulfate before anticipated preterm birth for
neuroprotection. ACOG committee opinion no. 455. Obstet Gynecol. 2010;115:669–671.
2. American College of Obstetricians and Gynecologists. Management of preterm labor. ACOG practice bulletin no. 127.
Obstet Gynecol. 2012;119:1308–1317.
3. American College of Obstetricians and Gynecologists. Prediction and prevention of preterm birth. ACOG practice
bulletin no. 130. Obstet Gynecol. 2012;120:964–973.
4. American College of Obstetricians and Gynecologists. Premature rupture of membranes. ACOG practice bulletin
no. 139. Obstet Gynecol. 2013;122:918–930.
5. Creasy RK, Resnik R, Iams JD, Lockwood CJ, Moore TR. Creasy and Resnik’s Maternal-Fetal Medicine: Principles and
Practice. 6th ed. Philadelphia: Saunders; 2009.
6. Creasy R, Resnik R, Iams JD, Lockwood CJ, Moore TR. Creasy and Resnik’s Maternal-Fetal Medicine: Principles and
Practice. 7th ed. Philadelphia: Saunders; 2014.
7. Fanaroff AA, Stoll BJ, Wright LL, et al. NICHD Neonatal Research Network: trends in neonatal morbidity and mortality
for very low birthweight infants. Am J Obstet Gynecol. 2007;196:147.e1–147.e8.
8. Morse SB, Haywood JL, Goldenberg RL, Bronstein J, Nelson KG, Carlo WA. Estimation of neonatal outcome and
perinatal therapy use. Pediatrics. 2000;105:1046–1050.
9. Kenyon SL, Taylor DJ, Tarnow-Mordi W. ORACLE Collaborative Group. Broad-spectrum antibiotics for preterm,
prelabour rupture of fetal membranes: the ORACLE I randomised trial. Lancet. 2001;357:979–988.
10. Lau C, Ambalavanan N, Chakraborty H, Wingate MS, Carlo WA. Extremely low birth weight and infant mortality rates in
the United States. Pediatrics. 2013;131:855–860.
11. Martin JA. Preterm births—United States, 2006 and 2010. MMWR Morb Mortal Wkly Rep. 2013;62:136–138.
12. McManemy J, Cooke E, Amon E, Leet T. Recurrence risk for preterm delivery. Am J Obstet Gynecol. 2007;196:576.
e1–576.e6. discussion 576.e6.
13. Mercer BM, Miodovnik M, Thurnau GR, et al. Antibiotic therapy for reduction of infant morbidity after preterm
premature rupture of the membranes: a randomized controlled trial. National Institute of Child Health and Human
Development Maternal-Fetal Medicine Units Network. JAMA. 1997;278:989–995.
14. National Institute of Child Health and Human Development (NICHD) Neonatal Research Network (NRN). Extremely
Preterm Birth Outcome Data. Available at www.nichd.nih.gov/about/org/der/branches/ppb/programs/epbo/Pages/
epbo_case.aspx. Accessed August 20, 2015.
15. National Institutes of Health (NIH) Consensus Developmental Panel. The effect of corticosteroids for fetal maturation
on perinatal outcomes. JAMA. 1995;273:413.
https://t.me/med1917
Соседние файлы в папке Библиотека им академика М.И. Перельмана