Most modern anesthesia workstations can display ventilator pressure and volume waveforms. These waveforms can be extremely useful to the anesthesia professional to detect and/or diagnose pulmonary and ventilator problems. In order to make effective use of these waveforms, the anesthesia professional must have an understanding of how these waveforms are generated, the physiology behind them, and how to interpret changes from normal.
In this article, the authors provide a stepwise approach to learning how to interpret these waveforms. They begin with a basic review of pulmonary physiology and then progress to examining the expiratory flow waveform. Many waveform examples are provided. The authors stress that these waveforms must be correlated with the clinical situation. For example, a reduced peak expiratory flow with a prolonged expiratory time could be due to a kinked ET tube or bronchospasm. They then continue to discuss the inspiratory flow and pressure waveforms. The differences between volume and pressure ventilation are illustrated and discussed. The authors state that mechanical waveform analysis is a useful tool in identifying pulmonary pathophysiology and improving patient safety.