201 - Test Characteristics of Point-of-Care Lung Ultrasound to Predict Discontinuation of Continuous Positive Airway Pressure

Poster Number: 201
Publication Number: 201.3144

Background: Continuous positive airway pressure (CPAP) is the mainstay of therapy for preterm infants with respiratory distress syndrome (RDS). However, the optimal timing and readiness criteria for weaning infants off CPAP lacks consensus. A score to predict successful CPAP discontinuation has the potential to standardize the practice. The point-of-care lung ultrasound (Brat R. JAMA Pediatr 2015) has been shown to correlate with oxygenation, with lower scores indicating better aerated lungs. While literature suggests lower scores predict successful weaning, an optimal cutoff score has yet to be determined.

Objective: This research seeks to evaluate test characteristics (sensitivity, specificity, and predictive values) of the lung ultrasound score to predict CPAP discontinuation when performed within one week of a discontinuation attempt. In addition, it seeks to determine an optimal cutoff score to best predict success.

Design/Methods: We analyzed the medical records of 132 patients with RDS born between 24 and 32 weeks’ gestation admitted to a Level IV neonatal intensive care unit. We collected the lung ultrasound scores of all infants who had a lung ultrasound performed within one week of a CPAP discontinuation attempt. Expert ultrasound “scorers” were blinded to the outcome of the attempts and scored all lung ultrasounds. We retrospectively assessed the outcome of “successful” CPAP discontinuation, defined as not requiring re-application of CPAP for at least 7 days following attempt. We then calculated the test characteristics for lung ultrasound score cutoffs between 0 and 8.

Results: 47 infants had a lung ultrasound performed within one week of a CPAP discontinuation attempt. Overall, point-of-care lung ultrasound predicts successful CPAP discontinuation. A lung ultrasound score cutoff ≤6 maximized sensitivity while a lung ultrasound score ≤3 maximized specificity. A lung ultrasound score cutoff ≤6 yields an optimal balance of sensitivity (100%) and specificity (82%) to predict CPAP discontinuation success with the highest Youden’s Index score of 0.82. See table 1.

Conclusion(s): Point-of-care lung ultrasound is a non-invasive tool that can rapidly evaluate oxygenation in preterm infants with a history of RDS. Ascertainment of the lung ultrasound score may aid in the decision to trial an infant off CPAP. More research is necessary to determine if using a lung ultrasound score cutoff of ≤6 may maximize CPAP weaning success in the clinical setting. Future work may incorporate the lung ultrasound into predictive models to provide real-time probability of CPAP discontinuation success.