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EHPLE Anesthesia study materials
EHPLE Anesthesia study resources

EHPLE Anesthesia: Special Populations and Comorbid Conditions

EHPLE Anesthesia · Work through your exam, one topic at a time.

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Special Populations and Comorbid Conditions

What this domain tests

This domain tests physiologic adjustments for pediatric, obstetric, geriatric, obese, and comorbid patients.

Core rules

  • Pediatric: weight-based dosing, higher MAC (sevoflurane about 2.5% in infants), bradycardia from hypoxia, laryngospasm, large head and small airway. Avoid succinylcholine in undiagnosed myopathy; caudal blocks suit infraumbilical surgery.
  • Obstetric: aortocaval compression after 20 weeks, left uterine displacement, rapid sequence for aspiration risk, smaller ETT 6.0-6.5, neuraxial preferred. Magnesium sulfate for preeclampsia requires monitoring of reflexes and respirations.
  • Geriatric: MAC falls about 6% per decade after 40; polypharmacy, delirium, falls, and frailty matter. Reduce doses and use regional techniques where possible.
  • Obesity: dose induction agents on lean body weight (propofol), succinylcholine on total body weight, maintain PEEP, use ramped position, and apply OSA precautions.
  • Comorbid disease: cirrhosis (avoid excess acetaminophen, expect coagulopathy), ESRD (avoid succinylcholine if potassium is high, adjust drugs), heart failure (careful fluids), pulmonary hypertension (avoid hypoxia, hypercarbia, and acidosis).

Worked example

A 32-week preeclamptic patient with platelets 90,000/µL needs cesarean delivery. Neuraxial anesthesia is preferred if coagulation is acceptable and platelets are stable; a spinal with a lower dose avoids airway manipulation. Magnesium sulfate is continued for seizure prophylaxis, and the anesthesiologist monitors deep tendon reflexes, respiratory rate, and urine output. The reasoning is that general anesthesia carries difficult-airway and hypertensive risks, while neuraxial avoids both if coagulation permits.

Traps

Dosing propofol on total body weight in obesity; giving succinylcholine to a child with undiagnosed muscular dystrophy; missing aortocaval compression; stopping magnesium before delivery; using standard adult doses in the elderly; ignoring OSA in a healthy-appearing obese patient.

Key points

  • Pediatric MAC is higher; infants are prone to hypoxia-induced bradycardia.
  • Left uterine displacement is needed after 20 weeks of pregnancy.
  • Elderly MAC decreases about 6% per decade after age 40.
  • Dose propofol on lean body weight in obesity; succinylcholine on total body weight.
  • Magnesium sulfate monitoring includes reflexes, respiratory rate, and urine output.