Oxygen cost of breathing and weaning process in newborn infants.

Newborn infants may have a high oxygen cost of breathing (OCB) at the time of being weaned from mechanical ventilation. We hypothesized that this increase in oxygen consumption (V'O2) could be reduced by using certain weaning ventilatory modes. We designed a study to assess V'O2 during three weaning ventilatory modes: patient triggered ventilation, synchronous intermittent mandatory ventilation (SIMV) and continuous positive airway pressure in 16 newborn infants before being weaned from mechanical ventilation In seven infants whose OCB was high. V'O2 was not significantly different between CV and PTV (8.9+/-0.6 versus 9.5+/-0.8, respectively) whereas it tended to increase to 10.8+/-1.1 mL x min(-1) x kg(-1) during SIMV and increased significantly to 11.9+/-0.8 mL x min(-1) x kg(-1). In the other nine infants whose OCB was normal, no significant variation of V'O2 was observed. Patient triggered ventilation was a weaning ventilatory mode that significantly reduced the increase in oxygen consumption observed in infants with a high oxygen cost of breathing, as compared to synchronous intermittent mandatory ventilation or continuous positive airway pressure. Further investigations in newborn infants with a high oxygen cost of breathing should be performed prior to routine use of patient triggered ventilation.