Abstract: Background and purpose: Obvious pulmonary dysfunction may exsist preoperatively in part of the patients undergoing pulmonary lobectomy. Volume-controlled ventilation (VC) during one-lung ventilation (OLV) may lead to lung injury in lung cancer patients with preoperative pulmonary dysfunction. However, pressure-regulated volume-controlled (PRVC) ventilation mode is a new type of ventilation mode, and can alleviate ventilation-induced lung injury. This study explored the effect of PRVC on respiratory mechanics, oxygenation index, pulmonary inflammatory response, and clinical outcomes in patients undergoing pulmonary lobectomy during OLV compared with VC mode. Methods: Forty ASA Ⅱ-Ⅲ patients with moderate to severe pulmonary dysfunction undergoing pulmonary lobectomy were randomly divided into group VC and group PRVC (n=20)．PRVC ventilation mode was performed for patients in group VC during the first 5 minutes after OLV, and then ventilation mode was switched to VC ventilation mode till the end of surgery. In the other group, ventilation modes were performed in reverse order. Ventilation settings remained unchanged when ventilation mode was switched. Respiratory mechanics, static lung compliance, hemodynamic parameters and arterial blood gas were obtained during the surgery. Blood samples and bronchoalveolar lavage (BALF) in ventilated lung were collected to determine the level of TNF-α, IL-1β, IL-6 and IL-8 at the end of surgery. Results: Both the peak expiratory pressure and static lung compliance in group PRVC were significantly lower than those in group VC (P<0.01). However, there were no statistical difference in hemodynamic parameters (heart rate and blood pressure) and arterial blood gas analysis (pH, paO₂ and paCO₂) between the two groups during OLV, as well as postoperative pulmonary complications and length of hospital stay. The levels of TNF-α, IL-1β and IL-6 in BALF in group PRVC were significantly lower than those in group VC (P<0.05), while there was no difference in blood sample. Conclusion: PRVC mode during OLV may relieve the extravagant airway pressure and then reduce the release of inflammatory factors in ventilation lung, which might prevent acute lung injury induced by lung barotraumas, especially for those patients with pulmonary dysfunction preoperatively. Therefore, PRVC mode is a safe and effective ventilation mode for high-risk patients undergoing pulmonary lobectomy.

Key words: Pressure-regulated volume controlled ventilation mode, Volume-controlled ventilation mode, Pulmonary lobectomy, One-lung ventilation