Abstract
BACKGROUND: The NeoVo2R, a volume-controlled resuscitator (VCR), can deliver an adjustable and known tidal volume. We conducted this study to determine whether this VCR can be used to measure total pulmonary compliance. DESCRIPTION OF DEVICE: The VCR studied consists of a hand-held bulb connected to an inflatable bellows inside a graduated cylinder. When the hand bulb is squeezed, the bellows expands and displaces an equal volume of oxygen or air from the graduated cylinder to a maximum of the preset volume. EVALUATION METHODS: Pressure-volume measurements comparing the VCR to an 80-mL syringe were made using 8 test lungs. Each test lung was inflated with several volumes (from 5 to 80 mL) via a 4-way stopcock using the VCR or the syringe in random order, and 2 plateau pressures were recorded. In a second experiment, 8 different test lungs were used to compare pressure-volume measurements using the VCR against the pneumotachygraph. Several pressure and volume recordings were made using each test lung, as the ventilator and VCR settings were adjusted to generate a compliance curve over a wide range of volumes and pressures. Regression lines and t tests were used to analyze the data. EVALUATION RESULTS: VCR vs syringe-the slopes and intercepts of regression lines were not significantly different (p > 0.5). VCR vs pneumotachygraph-the slopes of regression lines were not different (0.5 > p > 0.2). Mean compliances between the VCR and the syringe and pneumotachygraph were not significantly different (p = 0.93 and p = 0.84, respectively). CONCLUSION: Bench measurements suggest that the VCR studied may be useful as a simple bedside method of measuring total pulmonary compliance. Further testing in infants is warranted.
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