Comparison of volume-control and pressure-control ventilation during one-lung ventilation

We hypothesized that pressure control ventilation allows a more even distribution in the lung and better maintenance of the mean airway pressure than is achieved with volume control ventilation. We try to compare the effect of pressure control ventilation (PC) with that of volume control ventilation without an end-inspiratory pause (VC) during one-lung ventilation (OLV) in an anesthetized, paralyzed patient for performing thoracopic bullectomy of the lung.

We ventilated 20 patients with VC and PC after the insertion of a thoracoscope in continual order for, at least for 15 minutes, for each, VC and PC procedure. At the end of VC and PC, the respiratory mechanics, gasometrics, and hemodynamic parameters were measured and collected.

We found no significant differences between VC and PC except for the peak inspiratory airway pressure (PIP), the mean airway pressure and the arterial oxygen partial pressure (PaO2). The PIP was significantly decreased from 27.0 +/- 6.0 cmH2O (VC) to 21.8 +/- 5.4 cmH2O (PC). The mean airway pressure was significantly increased from 8.6 +/- 1.6 cmH2O (VC) to 9.4 +/- 2.0 cmH2O (PC), and the PaO2 was significantly increased from 252.9 +/- 97.3 mmHg (VC) to 285.2 +/- 103.8 mmHg (PC).

If PC allows mechanical ventilation with the same tidal volume and respiratory rate as VC during OLV, then PC significantly increases the PaO2 but this is not clinically significant, and the PC significantly decreases the PIP, which induces barotrauma or volutrauma when the PIP is excessively high.