A controlled comparison of two different calfactant preparations in a surfactant-deficient lamb model.

Abstract

Calfactant is an animal-derived surfactant, FDA-approved for endotracheal tube administration. Complications during surfactant administration may be related to the volume being delivered. We conducted a controlled comparison of calfactant against a more concentrated, lower-volume calfactant. We compared the efficacy and complications of delivery of the two calfactant formulations to each other, and to no surfactant treatment, in the well-established preterm newborn lamb model of surfactant-deficient respiratory distress syndrome. After initial stabilization, a single dose of liquid calfactant or sham air instillation was given, and animals were maintained on mechanical ventilation for up to 6 h. Reflux of surfactant into the endotracheal airway occurred in 83% of calfactant-treated lambs versus 33% of more concentrated, lower-volume calfactant-treated lambs. Lambs treated with a more concentrated, lower-volume calfactant required less positive-pressure breaths to clear refluxed surfactant (4 ± 2 vs. 30 ± 8) and less time to deliver surfactant (70 ± 10 vs. 130 ± 29 s). Ventilation and oxygenation improved significantly in surfactant-treated lambs, but not in controls. Four of six control lambs met adverse endpoint criteria before 6 h, whereas all surfactant-treated lambs remained stable up to 6 h. We conclude that a more concentrated, lower-volume calfactant has similar efficacy to calfactant but can be delivered more quickly and with less risk of complications.NEW & NOTEWORTHY In a preterm animal model of surfactant-deficient respiratory distress, we compared a concentrated, lower-volume calfactant to its commercial counterpart. The lower-volume calfactant could be administered in a single aliquot, was associated with less surfactant reflux, required less positive-pressure breaths to clear reflux, and had a shorter administration time. A more concentrated surfactant may offer a more favorable administration risk/benefit profile for surfactant replacement therapy, minimizing surfactant delivery-associated stress.