(204) Rhythm and Blues: A Case Report on Cardiac Arrhythmias Secondary to Propofol Infusion Syndrome

Introduction: Propofol-related infusion syndrome (PRIS) is a potentially fatal condition which has been increasingly described in children. One usually observes metabolic acidosis, hemodynamic instability and bradyarrhythmias. We describe a case of PRIS in the setting of tachyarrhythmias.

Description: A healthy 6-month-old male infant, weighing 8.9 kilograms, with bronchiolitis, developed respiratory failure on day 3 of illness.

He required mechanical ventilation and sedation with fentanyl and propofol. This was eventually transitioned to propofol monotherapy. The next morning, he was found to be obtunded with miotic pupils. He then developed runs of ventricular tachycardia, requiring multiple doses of magnesium and amiodarone. These events were followed by bradycardia with progressive worsening of lactic acidosis. He was transferred to the Pediatric Intensive Care Unit for escalation of care and consideration of ECMO. The calculated propofol infusion received was 12.9 mg/kg/hour (215 mcg/kg/minute) for approximately 13 hours.

Investigations were significant for Respiratory syncytial virus and Rhinovirus/Enterovirus. Electrocardiogram demonstrated monomorphic ventricular tachycardia. Echocardiogram showed preserved systolic function. Whole genome sequencing was unremarkable. His hospital course was complicated by focal seizures and subclinical status epilepticus; left middle cerebral artery hemorrhage and suspected toxic leukoencephalopathy; ventilator associated pneumonia and Clostridium difficile infection.

His presentation was consistent with PRIS and was treated with levocarnitine to promote free fatty acid metabolism. He developed seizures, which were well-controlled on levetiracetam. He required a tracheostomy and a gastrotomy tube. He was subsequently decannulated. He did not require hemodialysis or ECMO.

Discussion: This case highlights a rare, yet non-fatal, presentation of PRIS in an infant treated with a high dose of propofol in a short time period. Propofol toxicity has been reported following continuous infusion of propofol at a rate of 4-5 mg/kg/hour for over 48 hours. Risk factors include younger ages, higher doses, and longer durations. This case includes the addition of tachyarrhythmias as part of a multisystemic syndrome associated with this sedative in pediatrics.