Successful Direct Extubation of Very Low Birth Weight Infants From Low Intermittent Mandatory Ventilation Rate

Abstract
It is common practice to use endotracheal continuous positive airway pressure for various time periods up to 24 hours before attempting extubation in infants who are mechanically ventilated. A few studies in newborns have indicated that airway resistance is increased through small endotracheal tubes. This increases the work of breathing and the likelihood of subsequent ventilatory failure. In this study, 27 very low birth weight infants who were ½ to 28 days old at the time of extubation were randomly divided into two groups. One group of 13 study infants were extubated directly from intermittent mandatory ventilation rates of six to ten per minute, and the other 14 control infants were placed on continuous positive airway pressure through endotracheal tubes for six hours prior to an attempt to extubate. There was no difference between the two groups in gestational age, postnatal age, weight, or severity of lung disease at the time of extubation. All 13 study infants were successfully extubated without significant apnea or respiratory acidosis. Of the 14 control infants, only seven were successfully extubated; six infants had significant apnea and in one infant respiratory acidosis with pH 7.13 and Pco2 65 developed while receiving continuous positive airway pressure (13/13 v 7/14, P < .005). The seven infants who failed the preextubation trial of continuous positive airway pressure were later extubated from low intermittent mandatory ventilation rates without significant pnea or respiratory acidosis. Furthermore, slight CO2 retention developed in the very low birth weight infants after six hours of continuous positive airway pressure but not after direct extubation (mean change Pco2 ± SD: 4.43 ± 3.87 v -0.23 ± 3.79 mm Hg, P < .01). This study demonstrates that the recommended preextubation trial of continuous positive airway pressure through an endotracheal tube is not only unnecessary but detrimental to very low birth weight infants, in whom more apnea and slight CO2 retention develop probably because of increased airway resistance through small endotracheal tubes.