Maximum inspiratory pressure: a neonatal criterion for weaning from mechanical ventilation

Thirty-three newborn infants admitted to the neonatal intensive care unit of our hospital were studied. Mechanical ventilation was used for more than 24 hours for each patient. Maximum inspiratory pressure (MIP) was measured by means of a manometer at the oral end of the endotracheal tube just prior to extubation. Of the 33 studied neonates, 28 were successfully weaned at the first attempt of extubation (group I). Five neonates failed at the first attempt of extubation and required tracheal reintubation (group II). The mean birth weight was 1.78 +/- 0.86 kg, the mean gestational age was 32.6 +/- 4.3 weeks and the mean duration of intubation was 4.2 +/- 2.1 days in group I. The mean birth weight was 1.74 +/- 0.61 kg, the mean gestational age was 32.8 +/- 3.5 weeks and the mean duration of intubation was 7.0 +/- 2.6 days in group II. The mean MIP value in group I was -42.57 +/- 7.18 cm H2O and the mean MIP value in group II before the first attempt of extubation was -21.2 +/- 1.79 cm H2O. The patients in group I had a significantly lower MIP (P < 0.01) than group II, of the 28 patients in group I, 27 had MIP equal to or exceeding -35 cm H2O and only one case had MIP of -30 cm H2O. We conclude that measurement of MIP is a simple, useful and safe method for neonates to predict successful extubation from prolonged mechanical ventilation. A neonate with a MIP exceeding -35 cm H2O can be safely weaned from mechanical ventilation.