Predicting Early CPAP Failure

Ammari A, Suri M, Vladana M, et al. Variables Associated with the Early Failure of Nasal CPAP in Very Low Birth Weight Infants. J Pediatr (Sept 2005); 147: 341-347

Objective: To identify risk factors and neonatal outcomes associated with the early failure of “bubble” nasal continuous positive airway pressure (CPAP) in very low birth weight (VLBW) infants with respiratory distress syndrome (RDS).

Study design: Following resuscitation and stabilization at delivery, a cohort of 261 consecutively inborn infants (birth weight ≤1250 g) was divided into three groups based on the initial respiratory support modality and outcome at 72 hours of age: “ventilator-started” group, “CPAP-failure” group, and “CPAP-success” group.

Results: CPAP was successful in 76% of infants ≤1250 g birth weight and 50% of infants ≤750 g birth weight. In analyses adjusted for postmenstrual age (PMA) and small for gestational age (SGA), CPAP failure was associated with need for positive pressure ventilation (PPV) at delivery, alveolar-arterial oxygen tension gradient (A-a DO2) >180 mmHg on the first arterial blood gas (ABG), and severe RDS on the initial chest x-ray (adjusted odds ratio [95% CI]=2.37 [1.02, 5.52], 2.91 [1.30, 6.55] and 6.42 [2.75, 15.0], respectively). The positive predictive value of these variables ranged from 43% to 55%. In analyses adjusted for PMA and severe RDS, rates of mortality and common premature morbidities were higher in the CPAP-failure group than in the CPAP-success group.

Conclusion: Although several variables available near birth were strongly associated with early CPAP failure, they proved weak predictors of failure. A prospective controlled trial is needed to determine if extremely premature spontaneously breathing infants are better served by initial management with CPAP or mechanical ventilation.

Comments: The findings of this study are not unexpected. VLBW babies who fail on early CPAP were more likely to need bagging in the delivery room, and had worse lung disease based on blood gases and x-ray. There is strong evidence to support the practice of intubation and early surfactant treatment in the delivery room management of ELBW infants. However, centers like Columbia University (where the present study was done) have extremely low rates of chronic lung disease using the early CPAP strategy. The major drawback to a trial of early CPAP in these infants is the need to withhold (or delay) surfactant administration. A hybrid strategy has been suggested where ELBW infants are intubated, given surfactant treatment, then quickly extubated to CPAP support. The Early Delivery Room Management Trial is an ongoing, large, randomized, controlled trial comparing these 3 strategies. It is sponsored by the Vermont Oxford Network. I anxiously await the results of that study. ABK

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