PCV-VG combined individualized PEEP determination in one-lung ventilated patients with PEEP step change direction: A randomized controlled trial

Abstract

Introduction: The efficacy of pressure-controlled volume-guaranteed ventilation (PCV-VG) combined with a gradient-directional change in positive end-expiratory pressure (PEEP) during one-lung ventilation (OLV) in patients who underwent thoracoscopic surgery was investigated.

Methods: Ninety patients were randomly divided into the PC (PCV-VG + 5 cm H₂ O fixed PEEP), PI (PCV-VG + incremental PEEP titration), and PD (PCV-VG + decremental PEEP titration) groups. Hemodynamic (heart rate [HR] and mean arterial pressure [MAP]), respiratory mechanics (P_peak , P_mean, and Cdyn), and arterial blood gas (pH, PaCO₂ , PaO₂ , and PaO₂ /FiO₂ ) indices were evaluated at T₁ (10 min of two-lung ventilation [TLV]), T₂ (10 min of OLV), and T₃ (10 min of recovery, TLV). Enzyme-linked immunosorbent assay was performed to detect neutrophil elastase (NE), clara cell secretory protein (CC16), and interleukin-8 (IL-8) levels at T1 and T3.

Results: At T₂ and T₃ , P_peak was lower in the PI and PD groups than in the PC group, while P_mean and Cdyn were higher than in the PC group. P_peak in the PD group was lower than that in the PI group; however, P_mean was higher at T₂ and T₃ (P < 0.05). At T₂ , PaO₂ and PaO₂ /FiO₂ were higher, but PaO₂ /FiO₂ and V_D /V_T were lower in the PD and PI groups than in the PC group (P < 0.05). NE, CC16, IL-6, and IL-8 levels were elevated in all three groups at T₃ , but the PI and PD groups had lower levels than the PC group (P < 0.05). The incidences of postoperative pulmonary complications (PPCs) and surgical intensive care unit hospitalizations in the PD and PI groups were much lower.

Conclusion: Gradient-directed altered PEEP titration could improve respiratory mechanics, arterial blood gases, and inflammatory responses and reduce the incidence of PPCs in patients undergoing thoracoscopic surgery.

Keywords: one-lung ventilation; positive end-expiratory pressure; postoperative pulmonary complications; pressure-controlled volume guaranteed ventilation.