Identifying and treating intrinsic PEEP in infants with severe bronchopulmonary dysplasia

Rationale: Infants with severe bronchopulmonary dysplasia (sBPD) and airway obstruction may develop dynamic hyperinflation and intrinsic positive end-expiratory pressure (PEEP_i), which impairs patient/ventilator synchrony. Objectives: To determine if PEEP_i is present in infants with sBPD during spontaneous breathing and if adjusting ventilator PEEP improves patient/ventilator synchrony and comfort. Methods: Interventional study in infants with sBPD. PEEP_i measured by esophageal pressure (Pes) and pneumotachometer, during pressure-supported breaths. PEEP _i defined as the difference between Pes at start of the inspiratory effort minus Pes at onset of inspiratory flow. The set PEEP was adjusted to minimize PEEP _i. “Best PEEP” was the setting with minimal wasted efforts (WE), an inspiratory effort seen on the Pes waveform without a corresponding ventilator breath. FiO ₂ and SpO ₂ measured pre- and post-PEEP adjustment. Sedation requirements evaluated 72 hours preprocedure and postprocedure. Results: Twelve infants were assessed (gestational age, 24.9 ± 1.4 weeks; study age, 48.8 ± 1.5 weeks, postmenstrual age). Mean baseline ventilator PEEP was 16.4 cm H₂O (14-20 cm H ₂O). Eight infants required an increase, one, a reduction, and three, no change in the set PEEP. For the eight infants requiring an increase in set PEEP, there was an 18.9% reduction in WE and a reduction in FiO ₂ (0.084 ± 0.058) requirements in the subsequent 24 hours. Conditional sedation was reduced in five infants postprocedure. No adverse events occurred during testing. Conclusion: PEEP_i is measurable in infants with sBPD with concurrent esophageal manometry and flow-time tracings without the need for pharmacological paralysis. In those with PEEP _i, increasing ventilator PEEP to offset PEEP _i improves synchrony.