Comparative effects of variable versus conventional volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in thoracic surgery patients: A randomized controlled clinical trial

Research output: Contribution to journalResearch articleContributedpeer-review



BACKGROUND: Mechanical ventilation with variable tidal volumes (V-VCV) has the potential to improve lung function during general anesthesia. We tested the hypothesis that V-VCV compared to conventional volume-controlled ventilation (C-VCV) would improve intraoperative arterial oxygenation and respiratory system mechanics in patients undergoing thoracic surgery under one-lung ventilation (OLV).

METHODS: Patients were randomized to V-VCV (n = 39) or C-VCV (n = 39). During OLV tidal volume of 5 mL/kg predicted body weight (PBW) was used. Both groups were ventilated with a positive end-expiratory pressure (PEEP) of 5 cm H2O, inspiration to expiration ratio (I:E) of 1:1 (during OLV) and 1:2 during two-lung ventilation, the respiratory rate (RR) titrated to arterial pH, inspiratory peak-pressure ≤ 40 cm H2O and an inspiratory oxygen fraction of 1.0.

RESULTS: Seventy-five out of 78 Patients completed the trial and were analyzed (dropouts were excluded). The partial pressure of arterial oxygen (PaO2) 20 min after the start of OLV did not differ among groups (V-VCV: 25.8 ± 14.6 kPa vs C-VCV: 27.2 ± 15.3 kPa; mean difference [95% CI]: 1.3 [-8.2, 5.5], P = 0.700). Furthermore, intraoperative gas exchange, intraoperative adverse events, need for rescue maneuvers due to desaturation and hypercapnia, incidence of postoperative pulmonary and extra-pulmonary complications, and hospital free days at day 30 after surgery did not differ between groups.

CONCLUSIONS: In thoracic surgery patients under OLV, V-VCV did not improve oxygenation or respiratory system mechanics compared to C-VCV. Ethical Committee: EK 420092019.

TRIAL REGISTRATION: at the German Clinical Trials Register: DRKS00022202 (16.06.2020).


Original languageEnglish
Article number111444
JournalJournal of Clinical Anesthesia
Early online date6 Apr 2024
Publication statusE-pub ahead of print - 6 Apr 2024

External IDs

Scopus 85189443933
ORCID /0000-0002-5385-9607/work/157766766
ORCID /0000-0002-5224-1709/work/157767459
ORCID /0000-0003-4397-1467/work/157767940
ORCID /0000-0003-2185-1819/work/157769135
ORCID /0009-0006-9568-272X/work/158306425



  • Aged, Anesthesia, General/methods, Female, Humans, Male, Middle Aged, One-Lung Ventilation/methods, Oxygen/blood, Positive-Pressure Respiration/methods, Pulmonary Gas Exchange, Respiration, Artificial/methods, Respiratory Mechanics, Thoracic Surgical Procedures/adverse effects, Tidal Volume