TRIGGERING DELAY-TIME AND WORK OF BREATHING IN 3 PEDIATRIC PATIENT-TRIGGERED VENTILATORS

Purpose: To compare the effectiveness of three patient-triggered venti lators by evaluating triggering delay time and pressure-volume loops d uring initiation of inspiration. Methods: In a two-part study, a model lung was used in part I and 20 children, after tracheal intubation, i n part 2. Triggering delay time and work of breathing (WOB) during pre ssure support ventilation using three patient-triggered ventilators: S ervo Ventilator 300(TM), VIP Bird(TM), and SLE 2000 Neonatal Ventilato r(TM), Triggering delay time was from the beginning of negative deflec tion in the oesophageal pressure trace, to re onset of inspiration. Th e WOE was estimated directly by measuring the oesophageal pressure-vol ume loop, Results: The Servo demonstrated superior triggering delay ti me and reduced WOE in the model study The VIP Bird demonstrated shorte r triggering delay and reduced WOE in the clinical component of the st udy in the model lung, triggering delay time in the Servo 300 [62 +/- 6 msec (mean +/- SD)] was shorter than that in the VIP Bird (76 +/- 7 msec) (P < 0.05), and WOE with the SLE 2000 (202 +/- 37 g.cm) was grea ter than with other ventilators, (Servo 300, 112 +/- 32 gem and VIP Bi rd 72 +/- 41 g.cm) (P < 0.05), in the clinical study, triggering delay time in the VIP Bird (52 +/- 19 msec) was shorter than in the other v entilators, Servo 300 (66 +/- 14 msec), SLE 2000 (68 +/- 65 msec) (P < 0.05). The Servo 300 (56 +/- 34 g.cm) required higher WOE than the ot her ventilators: VIP Bird (22 +/- 12 g.cm), SLE 2000 (14 +/- 3 g.cm) ( P < 0.05, Conclusion: Comparative model lung performance of these vent ilators does not correspond with their clinical performance, In our cl inical evaluation, the VIP Bird ventilator demonstrated superior perfo rmance with shorter triggering delay time, low WOB needed to initiate inspiration, and little air leak.