EFFECTS OF FENTANYL ADMINISTRATION ON RESPIRATORY SYSTEM COMPLIANCE IN INFANTS

Objective. To determine if the analgesic doses of fentanyl used in a pediatric intensive care unit (ICU) setting adversely affect dynamic total respiratory system compliance in awake, intubated infants. Design: Prospective case-control study. Setting. Pediatric and pediatric cardiac ICUs of a tertiary university hospital. Patients. Thirteen awake and mechanically ventilated children <6 months of age. Interventions: Measurements of dynamic total respiratory system compliance were obtained during steady-state conditions for 6 mins and continued for 10 mins after the rapid, intravenous administration of 4 mug/kg of fentanyl. No patient had received a narcotic, benzodiazepine, or muscle relaxant within the previous 4 hrs. Measurements and Main Results: After fentanyl administration, dynamic total respiratory system compliance was unchanged in three patients, improved in nine patients, and deteriorated in one patient. The mean value for the entire group increased from 0.76 mL/cm H2O/kg before infusion to 0.82 mL/cm H2O/kg after infusion (p < .02), representing a 9.6% increase. None of the patients showed oxygen desaturation as assessed by continuous pulse oximeter, or episodes of chest wall rigidity. Conclusions: This work corroborates our clinical impression that rapid infusions of fentanyl at the dose tested in small infants do not adversely affect dynamic total respiratory system compliance. To the contrary, the sedating and analgesic effects may improve synchronous breathing and decrease voluntary muscle tone, resulting in improved dynamic total respiratory system compliance.