The importance of measurement of respiratory mechanics during surgery of the abdominal wall

Abstract

Assessment of respiratory mechanics is widely used in intensive care units in mechanically ventilated patients in order to assess the state of respiratory illness, the effects of pharmacological treatment, and the progression of the respiratory syndrome. Moreover, respiratory mechanics are also involved in monitoring respiratory function and muscle performance during weaning from the ventilator. In surgery of the abdominal wall with increase of abdominal pressure (large laparocele repair, decompression of abdominal compartment syndrome) the assessment of respiratory mechanics is a useful tool giving a better understanding of pathophysiologic implications. Intrao-peratively, it is important to detect variations from baseline values in order to avoid respiratory complications of surgical procedures. Non-invasive measurement of respiratory mechanics requires certain devices: a pneumotachograph connected to the endotracheal tube for measuring respiratory flow and tidal volume and two pressure transducers, one to measure the pressure at airway opening, the other to measure esophageal pressure by connection to an esophageal balloon. These signals are sent via an analog digital converter to a personal computer to be analysed and stored by dedicated respiratory mechanics software. The end-inspiratory occlusion technique and esophageal balloon technique make complete measurement of respiratory mechanics possible.