Comparison of airway pressure-triggered and airflow-triggered ventilation in very immature infants

Failure of patient-triggered Ventilation in very immature infants may be du e to the use of inappropriate triggering systems. Two types of airflow trig ger were therefore compared consecutively to an airway pressure (SLE) trigg ering system. Each comparison was made in 10 infants, less than or equal to 28 weeks of gestation. Comparison was made of the delivered volume, trigge r performance and blood gases using each system for 1 h. Both comparisons s howed that the airflow triggering systems performed better: one (Draeger Ba bylog 8000) had a higher sensitivity (p < 0.01) and the other (Bird VIP air flow trigger), in which inflation was terminated by sensing a reduction in inspiratory flow, had a lower degree of asynchrony (p < 0.01) and a tendenc y to deliver higher volumes. These results suggest that triggering systems sensing airflow changes may be superior to those sensing airway pressure ch anges in very immature infants. The use of a mechanism to synchronize the t ermination of inflation to the end of the patient's inspiration may offer f urther advantages.