Elimination of ventilator dead space during synchronized ventilation in premature infants☆
Section snippets
Endotracheal tube adapter continuous leakage technique
This technique consists of a 15-mm-long, open-ended tube with a resistance of 680 centimeters of water (cmH2O) per liter per second attached to the side port of the ETT adapter, as shown in Figure 1. Leakage flow determined by the positive end-expiratory pressure (PEEP) during mechanical expiratory time (Te) remains nearly constant. A PEEP of 4 cmH2O creates a leakage flow of approximately 0.35 liters per minute to clear a volume of 1.1 mL in 0.2 seconds. Leakage flow increases during
Results
Ten preterm infants were studied without adverse events. Their birth weight was 835±244 g and gestational age was 26±2 weeks. They were 19±9 days old and weighed 856±206 g at study time. Ventilatory support consisted of a mechanical rate of 21±6 breaths per minute, PIP of 16±1 cm H2O, and PEEP of 4.2±0.4 cm H2O and required an Fio2 of 0.26±0.6 to maintain Spo2 >90%. Ti ranged between 0.35 and 0.4 seconds and ventilator bias flow between 8 and 9 L/min. Eight infants were ventilated through a
Discussion
In this group of infants, sensor dead space increased CO2 rebreathing and resulted in a significantly higher alveolar CO2 and Tcpco2 and led to an increase in spontaneous compensatory respiratory effort during both conventional and synchronized ventilation. These effects were effectively prevented by the ETT adapter continuous leakage technique.
The effectiveness of the ETT adapter continuous leakage was increased by rapid clearance of exhaled CO2 at end-expiration, when concentration is
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Supported by the University of Miami Project Newborn.
Presented in part at the 2002 Society for Pediatric Research Meeting, Baltimore, Maryland.