Association of Intraoperative Ventilator Management With Postoperative Oxygenation, Pulmonary Complications, and Mortality

Abstract

BACKGROUND: “Lung-protective ventilation” describes a ventilation strategy involving low tidal volumes (VTs) and/or low driving pressure/plateau pressure and has been associated with improved outcomes after mechanical ventilation. We evaluated the association between intraoperative ventilation parameters (including positive end-expiratory pressure [PEEP], driving pressure, and VT) and 3 postoperative outcomes: (1) Pao 2/fractional inspired oxygen tension (Fio 2), (2) postoperative pulmonary complications, and (3) 30-day mortality. METHODS: We retrospectively analyzed adult patients who underwent major noncardiac surgery and remained intubated postoperatively from 2006 to 2015 at a single US center. Using multivariable regressions, we studied associations between intraoperative ventilator settings and lowest postoperative Pao 2/Fio 2 while intubated, pulmonary complications identified from discharge diagnoses, and in-hospital 30-day mortality. RESULTS: Among a cohort of 2096 cases, the median PEEP was 5 cm H2O (interquartile range = 4–6), median delivered VT was 520 mL (interquartile range = 460–580), and median driving pressure was 15 cm H2O (13–19). After multivariable adjustment, intraoperative median PEEP (linear regression estimate [B] = −6.04; 95% CI, −8.22 to −3.87; P < .001), median Fio 2 (B = −0.30; 95% CI, −0.50 to −0.10; P = .003), and hours with driving pressure >16 cm H2O (B = −5.40; 95% CI, −7.2 to −4.2; P < .001) were associated with decreased postoperative Pao 2/Fio 2. Higher postoperative Pao 2/Fio 2 ratios were associated with a decreased risk of pulmonary complications (adjusted odds ratio for each 100 mm Hg = 0.495; 95% CI, 0.331–0.740; P = .001, model C-statistic of 0.852) and mortality (adjusted odds ratio = 0.495; 95% CI, 0.366–0.606; P < .001, model C-statistic of 0.820). Intraoperative time with VT >500 mL was also associated with an increased likelihood of developing a postoperative pulmonary complication (adjusted odds ratio = 1.06/hour; 95% CI, 1.00–1.20; P = .042). CONCLUSIONS: In patients requiring postoperative intubation after noncardiac surgery, increased median Fio 2, increased median PEEP, and increased time duration with elevated driving pressure predict lower postoperative Pao 2/Fio 2. Intraoperative duration of VT >500 mL was independently associated with increased postoperative pulmonary complications. Lower postoperative Pao 2/Fio 2 ratios were independently associated with pulmonary complications and mortality. Our findings suggest that postoperative Pao 2/Fio 2 may be a potential target for future prospective trials investigating the impact of specific ventilation strategies for reducing ventilator-induced pulmonary injury.

Intraoperative Mechanical Ventilation and Postoperative Pulmonary Complications after Cardiac Surgery

“…Given these ranges, our cutoffs were selected by inspection of previously collected ventilation practice institutional data, targeting upper quartiles (approximately 75% compliance for each component) to ensure class balance between cases with LPV versus non-LPV and to improve multivariable model discrimination. 5,13,28,[38][39][40] Predicted body weight (PBW, in kg) was calculated as: 50 + 2.3 * (height (in) -60) for men; 45 + 2.3 * (height (in) -60) for women. 41 Modified airway driving pressure (ΔP) was calculated as (peak inspiratory pressure -PEEP).…”

Management of Intraoperative Mechanical Ventilation to Prevent Postoperative Complications after General Anesthesia: A Narrative Review

“…Atelectasis is also one of the most commonly occurring pulmonary complication after GA and may affect postoperative recovery; indeed, atelectasis is detectable for as long as 4 days in the postoperative evaluation [ 82 ] and has been associated with occurrence of pneumonia [ 80 ]. In support of this hypothesis, two large retrospective studies showed that high intraoperative FIO 2 was associated with a dose-dependent manner in major respiratory complications and with a 30-day mortality rate [ 83 , 84 ]. These results are not confirmed in an RCT comparing two “fixed” FIO 2 rate (30% vs. 80%), where no benefit or harmful effects were showed [ 85 ].…”

Clinically applicable approach for predicting mechanical ventilation in patients with COVID-19

“…To create these model, we first used least absolute shrinkage and selection operator (LASSO) using the proc hpgenselect procedure in SAS to select variables for inclusion at each prediction window as previously described. 17…”