Fentanyl-induced chest wall rigidity and laryngospasm in preterm and term infants

Objective: To assess the occurrence of muscle rigidity after fentanyl admin istration in premature and term neonates. Design: Prospective case series, observational study. Setting: A university hospital neonatal intensive care unit. Patients: 8/89 preterm end term infants (25-40 wks gestational age) who rec eived fentanyl for perioperative analgesia and sedation or intensive care p rocedures. Interventions: Mechanical or bag mask ventilation and antagonization with n aloxone. Measurements and Main Results: We observed chest wall rigidity in 8 patient s after low dosage of fentanyl (3-5 mu g/kg body weight). All patients pres ented with respiratory distress, hypercapnia, and hypoxemia leading to brad ycardia. In two patients, laryngospasm was noted and associated with muscle rigidity, thus making intubation impossible. Naloxone (20-40 mu g/kg body weight) reversed the laryngospasm and muscle rigidity immediately, allowing restitution within 1 min. In our patient population, we found fentanyl-ind uced chest wall rigidity in 4% of neonates after fentanyl administration. Conclusion: Even low doses of fentanyl can lead to thoracic rigidity in neo nates. Additionally, we observed laryngospasm in two patients and speculate that it might be a variant of muscle rigidity.