Association between inspired oxygen fraction and development of postoperative pulmonary complications in thoracic surgery: a multicentre retrospective cohort study

Abstract

Background: Limited data exist to guide oxygen administration during one-lung ventilation for thoracic surgery. We hypothesised that high intraoperative inspired oxygen fraction during lung resection surgery requiring one-lung ventilation is independently associated with postoperative pulmonary complications (PPCs).

Methods: We performed this retrospective multicentre study using two integrated perioperative databases (Multicenter Perioperative Outcomes Group and Society of Thoracic Surgeons General Thoracic Surgery Database) to study adult thoracic surgical procedures using one-lung ventilation. The primary outcome was a composite of PPCs (atelectasis, acute respiratory distress syndrome, pneumonia, respiratory failure, reintubation, and prolonged ventilation >48 h). The exposure of interest was high inspired oxygen fraction (FiO₂), defined by area under the curve of a FiO₂ threshold > 80%. Univariate analysis and logistic regression modelling assessed the association between intraoperative FiO₂ and PPCs.

Results: Across four US medical centres, 141/2733 (5.2%) procedures conducted in 2716 patients (55% female; mean age 66 yr) resulted in PPCs. FiO₂ was univariately associated with PPCs (adjusted OR [aOR]: 1.17, 95% confidence interval [CI]: 1.04-1.33, P=0.012). Logistic regression modelling showed that duration of one-lung ventilation (aOR: 1.20, 95% CI: 1.03-1.41, P=0.022), but not the time-weighted average FiO₂ (aOR: 1.01, 95% CI: 1.00-1.02, P=0.165), was associated with PPCs.

Conclusions: Our results do not support limiting the inspired oxygen fraction for the purpose of reducing postoperative pulmonary complications in thoracic surgery involving one-lung ventilation.

Keywords: hyperoxia; inspired oxygen fraction; lung resection; one-lung ventilation; postoperative pulmonary complications; protective ventilation; single-lung ventilation; thoracic surgery.

Fig 1

Derivation of the study cohort. MPOG, Multicenter Perioperative Outcomes Group; STS-GTSD, Society of Thoracic Surgeons General Thoracic Surgical Database.

Fig 2

Exposure variables for hypothetical cases of desaturation during one-lung ventilation. (a) Illustration of exposure variables for a hypothetical case depicting marginal oxygen saturation at the initiation of one-lung ventilation followed by improvement and subsequent weaning of FiO₂. (b) Illustration of exposure variables for a hypothetical case depicting severe oxygen desaturation (such as might be due to lung isolation device malposition), followed by correction and subsequent less aggressive weaning of FiO₂. AUC, area under the curve; FiO₂, inspired oxygen fraction; SpO₂, peripheral capillary oxygen saturation.

Fig 3

Trends in FiO₂ administration as a function of time after the start of one-lung ventilation. (a) Discretionary FiO₂ administration (25%, median, and 75%) as a function of time after the start of one-lung ventilation. (b) Percentage of cases using discretionary high FiO₂ (SpO₂ >98% at different FiO₂ thresholds) as a function of time after the start of one-lung ventilation. For any given time point on the x-axis, the height of the lines (25%, median, and 75%) utilises the measurements of only those patients whose one-lung ventilation period lasted to that point or beyond. Therefore, any downward trends may be due to FiO₂ levels decreasing over time for individual patients as one-lung ventilation continues, or the one-lung ventilation period ending for those patients receiving higher FiO₂, or both. FiO₂, inspired oxygen fraction; SpO₂, peripheral capillary oxygen saturation.