Differences in respiratory parameters during continuous positive airway pressure and pressure support ventilation in infants and children

The extubation criteria of pressure support ventilation (PSV) in infants and children were not yet established. We studied the differences in respiratory parameters during continuous positive airway pressure (CPAP) using a constant flow type ventilator and PSV using a demand valve type ventilator. Nineteen children (1.9±2.9 years old) who were ready to extubate were studied. All patients had recovered from their respiratory failure and had finished the weaning process of the ventilatory support. They were scheduled for extubation on the next day when their ventilatory mode had attained to a PSV of 3 cmH₂O with a positive end-expiratory pressure (PEEP) of 3 cmH₂O. On the extubation day, tidal volume (TV) and respiratory frequency (RR) were measured with a respiratory monitor at two modes (CPAP of 3 cmH₂O and PSV), and the duty ratio (DR) and mean inspiratory flow (MF) were calculated. The sequence of the ventilatory mode was random. No case, required reintubation. TV was 61.6±54.9 during CPAP and 67.7±61.4 ml during PSV, and RR was 38.5±10.6 and 37.1±8.8 beats/min., respectively. DR was 0.382± 0.067 and 0.359±0.085, and MF was 96.6±78.3 and 101.0±69.0 ml/sec., respectively. The measured parameters and calculated values showed no significant difference between CPAP and PSV. It was found that the respiratory parameters were almost the same with CPAP and PSV immediately before the extubation, and the previous extubation criteria of CPAP can be used. - respiratory parameters; spontaneous breathing; CPAP; PSV; infant and children