The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

NEONATAL MECHANICAL VENTILATOR TUBING COMPLIANCE, WHEN SHOULD CALCULATIONS BE PREFORMED?

Keith Hirst, Brian Walsh; Department of Respiratory Care, Childern’s Hospital Boston, Boston, MA

BACKGROUND: Newer generation ventilators utilize a tubing compliance factor from the pre-use checkout process to determine effective tidal volumes. Sometimes this pre-use check is preformed in accordance to the manufacturers’ recommendation; many times it is performed when the ventilator is turned around without water in the active humidification system. Additionally, many institutions have adopted the CDC recommendation for changing ventilator circuits PRN. This change in practice is supported by many departments as a cost saving initiative; however, from a performance perspective concerns have developed. We hypothesized that water in the chamber of two types of humidification systems as well as duration of use will not significantly affect the compliance factor of the ventilator circuits. METHOD: Two Servo-i ventilators were set up: one with a Concha III, one with Fisher Paykel 850 and a pre-use check was performed. For both humidification systems, a circuit compliance calculation was performed when the circuit was dry, filled with water at room temperature, then heated to 37C following one hour, three and seven days. Circuits were exposed to average ventilator settings of SIMV-PC RR-30 PIP-20, PEEP-5 and FIO2- .40. A Paired t test was used for statistical analysis. RESULTS: See figure 1. It should be noted that we had to clamp off the Concha bottle in order to get the Servo-i to calculate circuit compliance. Due to the fact that this is not how the Servo-i is operated in the clinical setting, we performed a hand calibration using a 150 mL calibrated syringe to 50 cmH2O and recorded the compliance factor. CONCLUSION: There was a statistically significant difference between the F&P dry versus wet; however it doesn’t appear to be clinically significant unless your birth weight is < 1 kg. The Servo could not calculate the Concha system with the water bottle in-line, which is very concerning as the compliance factor averages 1.0 mL/cmH2O difference between clamped and open to the water sources. This is clearly clinically significant for the entire neonatal population. Sponsored Research - None

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