Tocolysis for persistent fetal bradycardia
›Terbutaline
›Terbutaline 0.25 mg subcutaneously as a single dose
›May repeat once after 15 to 20 minutes if contractions and bradycardia persist
›Maximum approximately 0.5 mg in 4 hours in this setting
›Withhold or stop if the maternal heart rate exceeds 120 /min
›Beta-2 agonist; relaxes the myometrium to reduce contraction-driven cord compression as a bridge to delivery
›Cautions: maternal tachycardia, palpitations, hypotension, hyperglycemia, transient hypokalemia, and pulmonary edema (higher risk with multiple gestation, large fluid volumes, and concurrent corticosteroids)
›The beta-agonist hypokalemia is an intracellular shift, usually self-correcting, and does not need aggressive potassium replacement; on the maternal ECG watch for a prolonged QT, U waves, and ectopy, and note that concurrent magnesium sulfate adds PR prolongation and QRS widening
›Relatively contraindicated in significant maternal cardiac disease, tachyarrhythmia, and poorly controlled hyperthyroidism
›Nitroglycerin as an alternative uterine relaxant
›Nitroglycerin 50 to 100 mcg intravenously
›May repeat every 1 minute, titrated to uterine relaxation, to a total of about 200 mcg
›A sublingual metered spray 400 mcg is an alternative if there is no intravenous access
›Anticipate maternal hypotension; have a vasopressor drawn up before administration
›Nitric oxide donor; a very short-acting smooth muscle relaxant, preferred over terbutaline when maternal cardiac disease or tachyarrhythmia is present
›Tocolysis does not replace delivery; it buys minutes while the operating room is readied
Definitive delivery and timing
›Category 1 (crash) cesarean
›The default when vaginal delivery is not immediate
›Do not wait for a full antibiotic infusion, full monitoring, or laboratory results to start
›A low transverse or vertical uterine incision per operative findings and gestational age
›Reassessment in the operating room
›If the fetal heart rate fully recovers with elevation and the tracing normalizes, the obstetric team may de-escalate the urgency category while preparations continue
›Persistent bradycardia despite elevation proceeds to immediate delivery regardless of category
›Maternal cardiac arrest
›Perform a resuscitative (perimortem) cesarean with continuous manual left uterine displacement, aiming for delivery within about 5 minutes of arrest
Anesthesia considerations
›Neuraxial options
›Rapid top-up of a pre-existing labor epidural is the fastest neuraxial option if the catheter is known to be working
›A single-shot spinal is acceptable when the fetal heart rate has recovered and stabilized with elevation
›Prophylactic anticoagulation timing constrains neuraxial anesthesia (commonly 12 hours after a prophylactic and 24 hours after a therapeutic low-molecular-weight heparin dose), often forcing general anesthesia in a crash case
›General anesthesia when no working epidural is in place
›Rapid sequence induction with cricoid pressure, a ramped position, preoxygenation, and maintained left uterine displacement
›Anticipate a difficult airway: mucosal edema, reduced functional residual capacity, and rapid desaturation
›Induction: propofol 2 to 2.5 mg/kg intravenously, or ketamine 1 to 1.5 mg/kg intravenously if hypotensive or hemorrhaging
›Neuromuscular blockade: succinylcholine 1 to 1.5 mg/kg intravenously, or rocuronium 1.2 mg/kg intravenously
›Aspiration prophylaxis if time allows: non-particulate antacid (sodium citrate 30 ml orally) plus an intravenous H2 antagonist
›Analgesic adjunct: fentanyl 1 to 2 mcg/kg intravenously crosses the placenta and can depress the newborn, so alert the neonatal team
Maternal hemodynamic support
›Blood pressure target and its exceptions
›Maintain systolic pressure within 10 to 20% of the maternal baseline to preserve uteroplacental perfusion
›Chronic hypertension: keep pressure near the patient's usual range and do not drive it low
›Preeclampsia: avoid hypotension and also treat severe-range blood pressure at or above 160/110 mmHg
›Phenylephrine
›Phenylephrine 50 to 100 mcg intravenous bolus, or an infusion 25 to 50 mcg/min
›Titrate to maternal systolic blood pressure every 1 to 2 minutes during a neuraxial block
›Alpha-1 agonist; the preferred first-line pressor in obstetrics because it preserves uteroplacental flow
›May cause reflex maternal bradycardia; reduce or pause the infusion if it occurs
›Ephedrine
›Ephedrine 5 to 10 mg intravenous bolus, repeat every 3 to 5 minutes, maximum about 50 mg
›Mixed alpha and beta agonist; preferred when hypotension is accompanied by maternal bradycardia
›Higher cumulative doses cross the placenta and are associated with fetal acidemia, so it is second-line to phenylephrine
›Position and a crystalloid co-load accompany pressors rather than replace them
Antenatal neuroprotection, lung maturity, and RhD prophylaxis
›Magnesium sulfate for fetal neuroprotection when gestation is below 32 weeks
›Magnesium sulfate 4 g intravenously over 20 to 30 minutes, then a 1 g/hour infusion
›Monitor deep tendon reflexes, a respiratory rate above 12 /min, and urine output above 100 ml per 4 hours
›Calcium gluconate 1 g (10 ml of 10%) intravenously over 3 minutes as the antidote for magnesium toxicity
›Do not delay delivery to load magnesium; give it perioperatively or en route if feasible
›Antenatal corticosteroids for lung maturity between 24 0/7 and 33 6/7 weeks, and up to 36 6/7 weeks if late preterm and not previously treated
›Betamethasone 12 mg intramuscularly, two doses 24 hours apart
›Dexamethasone 6 mg intramuscularly every 12 hours for four doses is an alternative
›Delivery is never delayed for a steroid course in an ongoing cord prolapse
›RhD immune globulin for an RhD-negative mother with an at-risk infant
›RhD immune globulin 300 mcg intramuscularly after delivery
›Increase the dose based on a quantitative fetal-maternal hemorrhage assay if a large bleed is suspected
›Surgical antibiotic prophylaxis for cesarean
›Cefazolin 2 g intravenously within 60 minutes before skin incision, or 3 g if maternal weight is 120 kg or more
›Add azithromycin 500 mg intravenously for a non-elective or intrapartum cesarean
›Severe penicillin or cephalosporin allergy: clindamycin 900 mg intravenously plus gentamicin 5 mg/kg intravenously
›Give it as the patient goes to the operating room; do not delay a crash cesarean for the infusion to finish
›Group B streptococcus prophylaxis if colonized, if status is unknown with risk factors, or with a prior infant with invasive disease
›Penicillin G 5 million units intravenously once, then 2.5 to 3 million units intravenously every 4 hours until delivery
›Cefazolin 2 g intravenously once, then 1 g every 8 hours, for a low-risk penicillin allergy
›Clindamycin 900 mg intravenously every 8 hours only if the isolate is clindamycin-susceptible
›Vancomycin 20 mg/kg intravenously every 8 hours (maximum 2 g per dose) for a high-risk allergy with clindamycin resistance or unknown susceptibility
›Cefazolin surgical prophylaxis given for cesarean also covers group B streptococcus, and emergency delivery is not delayed for a separate GBS dose
Neonatal resuscitation and post-delivery care
›Preparation
›Neonatal team present with a resuscitation platform, warm towels, and equipment checked before delivery
›Delayed cord clamping is deferred if the neonate needs immediate resuscitation
›Ventilation and oxygen
›Effective positive-pressure ventilation is the priority for a bradycardic or apneic newborn
›Begin with 21% oxygen at term and 21 to 30% preterm, titrated to preductal SpO2 targets
›Preductal SpO2 targets: about 60 to 65% at 1 minute, 65 to 70% at 2 minutes, 70 to 75% at 3 minutes, 80 to 85% at 5 minutes, and 85 to 95% at 10 minutes
›Chest compressions at a 3:1 compression-to-ventilation ratio if the heart rate stays below 60 /min after 30 seconds of effective ventilation
›Neonatal epinephrine
›Epinephrine 0.01 to 0.03 mg/kg (0.1 to 0.3 ml/kg of the 0.1 mg/ml concentration) intravenously or intraosseously, repeated every 3 to 5 minutes
›Endotracheal 0.05 to 0.1 mg/kg only if there is no vascular access, while access is obtained
›Verify against current pediatric guideline before use
›Volume expansion for suspected acute blood loss (vasa previa, cord hemorrhage) or shock unresponsive to resuscitation
›Normal saline or O RhD-negative red cells 10 ml/kg intravenously or intraosseously over 5 to 10 minutes, repeated as needed
›Verify against current pediatric guideline before use
›Neonatal hypoglycemia
›Dextrose 10% 2 ml/kg intravenous bolus for a glucose below 2.6 mmol/l, followed by a maintenance dextrose infusion
›Verify against current pediatric guideline before use
›Naloxone
›Naloxone is not given routinely to a depressed newborn (historic dose 0.1 mg/kg intravenously); it is contraindicated when the mother is opioid-dependent because it can precipitate neonatal seizures, so support ventilation instead
›Verify against current pediatric guideline before use
›Empiric neonatal antibiotics if early-onset sepsis is a concern (prolonged rupture, maternal fever, instrumentation)
›Ampicillin plus gentamicin, not ampicillin monotherapy, for a neonate under 4 weeks, dosed by postmenstrual and postnatal age from the current neonatal formulary
›Verify against current pediatric guideline before use
›Therapeutic hypothermia for moderate to severe hypoxic-ischemic encephalopathy
›Infants at 36 weeks or more, initiated within 6 hours of birth, target core temperature 33.5°C for 72 hours
›Begin passive cooling and stop active warming while arranging transfer; avoid overcooling and hyperthermia
›Verify against current pediatric guideline before use
›Send paired umbilical cord gases and place the infant on a neurologic assessment pathway
Interventions to avoid or modify
›Cord-directed maneuvers
›Funic reduction (manually replacing the cord in the uterus): avoid; it delays delivery and worsens outcomes
›Repeated or prolonged cord palpation and milking: avoid; it provokes vasospasm
›Timing and transport errors
›Delaying delivery for imaging, laboratory results, or a full antibiotic infusion in a viable bradycardic fetus: avoid
›Supine or upright transport without left uterine displacement: avoid; aortocaval compression worsens fetal hypoxia
›Crash cesarean once fetal death is confirmed: avoid; it adds maternal surgical risk with no fetal benefit
›Drug and fluid pitfalls
›Excessive or repeated terbutaline: avoid; maternal tachycardia, hypotension, and pulmonary edema reduce uteroplacental perfusion
›Large-volume fluid resuscitation with a beta-agonist tocolytic on board: modify; cap the volume and monitor for pulmonary edema
›Antenatal nonsteroidal anti-inflammatory drugs (for example ketorolac 30 mg intravenously every 6 hours, maximum 120 mg/day for up to 5 days): avoid before delivery for risk of ductus arteriosus constriction and oligohydramnios; acceptable after delivery
›Sustained high-concentration maternal oxygen well beyond delivery preparation: modify; the benefit is unproven and it is only a bridge
›Routine maternal sedation: avoid; benzodiazepines cross the placenta and cause neonatal respiratory depression and hypotonia, and sedation impairs the mother's ability to hold position
›Procedural and circulatory support
›Intubation and general anesthesia: modify; anticipate a difficult obstetric airway and rapid desaturation, and use rapid sequence induction with cricoid pressure, a ramped position, left uterine displacement, and aspiration prophylaxis
›Vasopressors: use phenylephrine first to preserve uteroplacental flow, avoid high cumulative ephedrine, and do not chase a number with pure vasoconstriction at the expense of uterine perfusion
›Anticoagulation: hold prophylactic and therapeutic heparin; the last-dose time dictates neuraxial safety and often forces general anesthesia
›Analgesia: acetaminophen 1 g intravenously or orally every 6 hours (maximum 4 g/day) is safe; systemic opioids depress the newborn, so have the neonatal team ready
›Intra-aortic balloon pump and other mechanical circulatory support: not applicable; there is no role in this condition, and in maternal arrest the priority is resuscitative cesarean with manual left uterine displacement
›Fibrinolysis: contraindicated in the peripartum period because of catastrophic hemorrhage risk
›When the fetal heart rate does not recover despite elevation and positioning
›Confirm the hand is actually holding the presenting part off the cord and reposition it
›Add bladder filling and give or repeat terbutaline
›Exclude and correct maternal hypotension and the supine position
›Use bedside ultrasound to confirm ongoing fetal cardiac activity
›Proceed to immediate delivery regardless and prepare full neonatal resuscitation and a hypoxic-ischemic encephalopathy pathway