Patient-Ventilator Asynchrony and Standard Waveforms: Looks Can Be Deceiving—Reply

In reply:

We sincerely thank Jeffrey Haynes for his comments on our study.¹ We agree with Mr Haynes when he points out that there are occasions in which patient-ventilator asynchrony cannot be identified by standard waveform analysis and that other assessment tools, such as diaphragmatic electromyography, are needed to effectively identify its presence. This is a very important point, considering that a significant percentage of asynchronies are underestimated using standard waveform analysis. However, identifying patient-ventilator asynchrony using waveform analysis is an available tool in all modern mechanically ventilators that has been shown to have good correlation with other methods, such as diaphragmatic pressure measurement.²

It is also important to consider that diaphragmatic electromyography has proved to be a very useful tool to obtain very interesting results from the physiological point of view,³ but it is not frequently used during daily clinical practice to identify patient-ventilator asynchrony in mechanically ventilated patients in the ICU. It could be an interesting idea to develop some cost-effectiveness studies in which we could investigate whether reducing patient-ventilator asynchrony through correct interpretation of standard waveform analysis improves clinical outcomes with regard to incremental cost-effectiveness ratios. Finally, it is important to remember that the main objective of our study was not to determine the best method or tool to identify patient-ventilator asynchrony, but to assess the ability of ICU health-care professionals to identify patient-ventilator asynchrony using standard waveform analysis.

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