Influence of liberal versus conservative oxygen therapies on the hemodynamic parameters of mechanically ventilated patients with sepsis: a randomized clinical trial

Background: There is no significant evidence verifying the efficacy of liberal versus conservative oxygen therapy on hemodynamics in patients with sepsis. We investigated how liberal and conservative oxygen therapy influenced stroke volume, cardiac output, and vasopressor needs in patients with sepsis undergoing mechanical ventilation.

Methods: This randomized clinical trial included 106 patients with an admission diagnosis of infection, a Sequential Organ Failure Assessment (SOFA) score of two points or higher and required invasive mechanical ventilation for at least 72 h. Patients were randomly assigned to one of two oxygenation strategies: liberal (n = 53) with a target SpO2 of ≥ 96% or conservative (n = 53) with a target SpO2 of 88-92%. Transthoracic Doppler echocardiography was done twice to measure stroke volume and cardiac output, initially upon enrollment in the trial and then 72 h later. The primary outcome was stroke volume. Secondary outcomes were cardiac output, vasopressor use, mechanical ventilation duration, ICU stay length, and adverse events.

Results: Stroke volume and cardiac output measurements did not differ significantly between research groups after 72 h of oxygenation treatment (p = 0.459 and 0.637, respectively). Forty-five patients (84.9%) in the conservative oxygen therapy group needed vasopressors to maintain their mean arterial pressure above 65 mmHg, whereas 35 patients (66.0%) in the liberal group did (p = 0.024). A multivariate logistic regression analysis of the independent variables for vasopressor requirements revealed that patients in the conservative oxygen group were 3.83 times more likely to require vasopressors (AOR = 3.83, 95% CI: 1.31-11.18, p = 0.014) than those in the liberal group. Older patients (AOR = 1.03, 95% CI: 1.01-1.07, p = 0.038) and those with higher SOFA scores (AOR = 1.36, CI: 1.09-1.68, P = 0.005) were significantly more likely to need vasopressors.

Conclusions: Liberal or conservative oxygen therapy did not influence stroke volume or cardiac output measurements in mechanically ventilated patients with sepsis. Patients in the conservative oxygen group were more likely to require vasopressors than those in the liberal group.

Trial registration: This study was approved by the Ethics Committee of Aswan University Hospital (approval number: Aswu/460/5/20) (registration date: 05/05/2020) and registered on ClinicalTrials.gov (NCT04824703) (03/30/2021).