Open-lung ventilation and mechanical power in thoracic surgery: Post hoc analysis of a multicentre randomised trial.

Postoperative pulmonary complications (PPCs) are frequent and serious complications after esophagectomy. Our aim was to determine intraoperative ventilatory parameters that are independently associated with PPCs during one-lung ventilation (OLV) and two-lung ventilation (TLV) phases. This retrospective single-center cohort study included 454 patients undergoing elective esophagectomy with combined abdominal and thoracic approaches. The primary outcome was the occurrence of PPCs within seven postoperative days. Separate predictive models were established for OLV and TLV using multivariable logistic regressions with ventilatory parameters. PPCs occurred in 194 patients (42.7%). Plateau pressure (Pplat) and driving pressure (DP) were independently associated with PPCs during both phases (Pplat: OR = 1.73, 95%CI: 1.25-2.38, p < 0.001 in OLV; OR = 1.38, 95%CI: 1.00-1.92, p = 0.05 in TLV; DP: OR = 1.17, 95%CI: 1.05-1.30, p = 0.005 in OLV; OR = 1.14, 95%CI: 1.06-1.23, p < 0.001 in TLV). Respiratory rate (RR) was also associated (OR up to 1.62). In TLV, duration of ventilation (OR between 1.39 and 1.41) was associated with PPCs, while positive end-expiratory pressure (PEEP) was protective (OR 0.73). In OLV only, higher tidal volume (VTe) (OR 1.31, 95%CI: 1.303, 1.66, p = 0.02) and mechanical power (MP) (OR = 1.29, 95%CI: 1.00-1.64, p = 0.05) were associated with PPCs. Model discrimination was acceptable (AUC 0.70-0.76). Pplat, RR, and DP were associated with PPCs in both ventilation phases. During TLV, duration increased and PEEP decreased PPC risk, whereas during OLV, VTe and MP were associated with PPCs.

What is the Ideal Tidal Volume During One-Lung Ventilation?

Effects of intraoperative higher versus lower positive end-expiratory pressure during one-lung ventilation for thoracic surgery on postoperative pulmonary complications (PROTHOR): a multicentre, international, randomised, controlled, phase 3 trial.

BackgroundThe interest in perioperative lung protective ventilation has been increasing. However, optimal management during one-lung ventilation (OLV) remains undetermined, which not only includes tidal volume (VT) and positive end-expiratory pressure (PEEP) but also inspired oxygen fraction (FIO2). We aimed to investigate current practice of intraoperative ventilation during OLV, and analyze whether the intraoperative ventilator settings are associated with postoperative pulmonary complications (PPCs) after thoracic surgery.MethodsWe performed a prospective observational two-center study in Japan. Patients scheduled for thoracic surgery with OLV from April to October 2014 were eligible. We recorded ventilator settings (FIO2, VT, driving pressure (ΔP), and PEEP) and calculated the time-weighted average (TWA) of ventilator settings for the first 2 h of OLV. PPCs occurring within 7 days of thoracotomy were investigated. Associations between ventilator settings and the incidence of PPCs were examined by multivariate logistic regression.ResultsWe analyzed perioperative information, including preoperative characteristics, ventilator settings, and details of surgery and anesthesia in 197 patients. Pressure control ventilation was utilized in most cases (92%). As an initial setting for OLV, an FIO2 of 1.0 was selected for more than 60% of all patients. Throughout OLV, the median TWA FIO2 of 0.8 (0.65-0.94), VT of 6.1 (5.3-7.0) ml/kg, ΔP of 17 (15-20) cm H2O, and PEEP of 4 (4-5) cm H2O was applied. Incidence rate of PPCs was 25.9%, and FIO2 was independently associated with the occurrence of PPCs in multivariate logistic regression. The adjusted odds ratio per FIO2 increase of 0.1 was 1.30 (95% confidence interval: 1.04-1.65, P = 0.0195).ConclusionsHigh FIO2 was applied to the majority of patients during OLV, whereas low VT and slight degree of PEEP were commonly used in our survey. Our findings suggested that a higher FIO2 during OLV could be associated with increased incidence of PPCs.

Background:Positive end-expiratory pressure (PEEP) is an important part of the lung protection strategies for one-lung ventilation (OLV). However, a fixed PEEP value is not suitable for all patients. Our objective was to determine the prevention of individualized PEEP on postoperative complications in patients undergoing one-lung ventilation.Method:We searched the PubMed, Embase, and Cochrane and performed a meta-analysis to compare the effect of individual PEEP vs fixed PEEP during single lung ventilation on postoperative pulmonary complications. Our primary outcome was the occurrence of postoperative pulmonary complications during follow-up. Secondary outcomes included the partial pressure of arterial oxygen and oxygenation index during one-lung ventilation.Result:Eight studies examining 849 patients were included in this review. The rate of postoperative pulmonary complications was reduced in the individualized PEEP group with a risk ratio of 0.52 (95% CI:0.37–0.73; P = .0001). The partial pressure of arterial oxygen during the OLV in the individualized PEEP group was higher with a mean difference 34.20 mm Hg (95% CI: 8.92–59.48; P = .0004). Similarly, the individualized PEEP group had a higher oxygenation index, MD: 49.07mmHg, (95% CI: 27.21–70.92; P < .0001).Conclusions:Individualized PEEP setting during one-lung ventilation in patients undergoing thoracic surgery was associated with fewer postoperative pulmonary complications and better perioperative oxygenation.

Protective ventilation may improve outcomes after major surgery. However, in the context of one-lung ventilation, such a strategy is incompletely defined. The authors hypothesized that a putative one-lung protective ventilation regimen would be independently associated with decreased odds of pulmonary complications after thoracic surgery. The authors merged Society of Thoracic Surgeons Database and Multicenter Perioperative Outcomes Group intraoperative data for lung resection procedures using one-lung ventilation across five institutions from 2012 to 2016. They defined one-lung protective ventilation as the combination of both median tidal volume 5 ml/kg or lower predicted body weight and positive end-expiratory pressure 5 cm H2O or greater. The primary outcome was a composite of 30-day major postoperative pulmonary complications. A total of 3,232 cases were available for analysis. Tidal volumes decreased modestly during the study period (6.7 to 6.0 ml/kg; P < 0.001), and positive end-expiratory pressure increased from 4 to 5 cm H2O (P < 0.001). Despite increasing adoption of a "protective ventilation" strategy (5.7% in 2012 vs. 17.9% in 2016), the prevalence of pulmonary complications did not change significantly (11.4 to 15.7%; P = 0.147). In a propensity score matched cohort (381 matched pairs), protective ventilation (mean tidal volume 6.4 vs. 4.4 ml/kg) was not associated with a reduction in pulmonary complications (adjusted odds ratio, 0.86; 95% CI, 0.56 to 1.32). In an unmatched cohort, the authors were unable to define a specific alternative combination of positive end-expiratory pressure and tidal volume that was associated with decreased risk of pulmonary complications. In this multicenter retrospective observational analysis of patients undergoing one-lung ventilation during thoracic surgery, the authors did not detect an independent association between a low tidal volume lung-protective ventilation regimen and a composite of postoperative pulmonary complications.

BackgroundMinimally invasive Ivor Lewis esophagectomy (MIE) is a primary treatment option for esophageal cancer. However, intraoperative pneumoperitoneum and one-lung ventilation (OLV) significantly alter respiratory mechanics, potentially leading to hypoxemia and postoperative pulmonary complications (PPCs). The objective of this study was to evaluate the effects of a driving pressure (DP)-guided lung-protective ventilation strategy on respiratory mechanics, oxygenation levels, and the occurrence of PPCs in patients undergoing MIE.MethodsThis study was a single-center, prospective, randomized controlled clinical trial. Sixty patients undergoing MIE were randomly assigned to either a conventional lung-protective ventilation strategy group (VC group) or a DP-guided lung-protective ventilation strategy group (VD group). In the VC group, positive end-expiratory pressure (PEEP) was set at a fixed level of 5 cmH2O. In the VD group, PEEP was individualized and adjusted based on DP at three specific times: 5 min after tracheal intubation, at the start of OLV, and when total lung ventilation resumed. The primary outcome was dynamic lung compliance (Cdyn). Data on respiratory mechanics, PaO2, PaCO2, pH, and hemodynamic parameters were collected. Additionally, the occurrence of PPCs within 7 days was recorded.ResultsA total of 59 patients were analyzed, including 30 in the VC group and 29 in the VD group. The VD group showed significantly higher Cdyn than the VC group, especially at 30 min after OLV (median difference of 9.0 mL/cmH2O; 95% confidence interval: 4.00 to 10.00; P<0.001). Compared to the VC group, the VD group showed significantly lower peak pressure and plateau pressure during surgery (P<0.05). During OLV, patients in the VD group showed significantly higher PaO2 and PaCO2 levels than those in the VC group (P<0.05). There were no statistically significant differences in hemodynamic parameters between the two groups. The incidence of PPCs was lower in the VD group (24.1% vs. 43.3%), but this difference failed to achieve statistical significance (P>0.05).ConclusionsIn patients undergoing MIE, implementing a DP-guided lung-protective ventilation strategy significantly improved intraoperative respiratory mechanics and oxygenation parameters while maintaining relatively stable hemodynamics, but failed to reduce clinically relevant outcomes such as PPCs within 7 days.Trial RegistrationThis study was registered at Chinese Clinical Trial Registry (ChiCTR2400089494).

Effects of Individualized Positive End-Expiratory Pressure on Patients Undergoing One-Lung Ventilation During Thoracic Surgery: A Systematic Review and Meta-Analysis.

BACKGROUNDPrevious studies have discussed the correlation between mechanical power (MP) and lung injury. However, evidence regarding the relationship between MP and postoperative pulmonary complications (PPCs) in children remains limited, specifically during one-lung ventilation (OLV).OBJECTIVESPropensity score matching was employed to generate low MP and high MP groups to verify the relationship between MP and PPCs. Multivariable logistic regression was performed to identify risk factors of PPCs in young children undergoing video-assisted thoracic surgery (VATS).DESIGNA retrospective study.SETTINGSingle-site tertiary children's hospital.PATIENTSChildren aged ≤2 years who underwent VATS between January 2018 and February 2023.INTERVENTIONSNone.MAIN OUTCOME MEASURESThe incidence of PPCs.RESULTSOverall, 581 (median age, 6 months [interquartile range: 5–9.24 months]) children were enrolled. The median [interquartile range] MP during OLV were 2.17 [1.84 to 2.64) J min−1. One hundred and nine (18.76%) children developed PPCs. MP decreased modestly during the study period (2.63 to 1.99 J min−1; P < 0.0001). In the propensity score matched cohort for MP (221 matched pairs), MP (median MP 2.63 vs. 1.84 J min−1) was not associated with a reduction in PPCs (adjusted odds ratio, 1.43; 95% CI, 0.87 to 2.37; P = 0.16). In the propensity score matched cohort for dynamic components of MP (139 matched pairs), dynamic components (mean 2.848 vs. 4.162 J min−1) was not associated with a reduction in PPCs (adjusted odds ratio, 1.62; 95% CI, 0.85 to 3.10; P = 0.15).The multiple logistic analysis revealed PPCs within 7 days of surgery were associated with male gender, OLV duration >90 min, less surgeon's experience and lower positive end-expiratory pressure (PEEP) value.CONCLUSIONSMP and dynamic components were not associated with PPCs in young children undergoing VATS, whereas PPCs were associated with male gender, OLV duration >90 min, less surgeon's experience and lower PEEP value.TRIAL REGISTRATIONChiCTR2300074649.

BackgroundThe risk of postoperative pulmonary complications is significantly increased in patients undergoing video-assisted thoracic surgical lobectomy. Individualized positive end-expiratory pressure (PEEP) is extensively employed to optimize respiratory mechanics and enhance oxygenation during one-lung ventilation (OLV). However, there is no consensus regarding the optimal level of positive end-expiratory pressure and its effects during OLV. Therefore, we designed a randomized controlled trial to assess whether titrating PEEP to the maximum dynamic lung compliance in patients undergoing lung resection surgery impacts the occurrence of postoperative pulmonary complications (PPCs).MethodsIn this randomized controlled trial, patients undergoing thoracoscopic lobectomy were randomly assigned to either a dynamic lung compliance group that received individualized PEEP guided by the maximum dynamic pulmonary compliance or a conventional ventilation group with a fixed PEEP of 5 cm H2O. The primary outcome was a composite of PPCs occurring within seven days, as defined by the European Perioperative Clinical Outcome criteria. Secondary outcomes included PEEP, Cdyn, PaO2, serum concentrations of IL-6 and TNF-α, and the duration of postoperative hospital stays.ResultsOne hundred patients were enrolled. The optimal PEEP obtained in the dynamic lung compliance group was 9.04 ± 1.83 cm H2O. Patients in the conventional ventilation group experienced 38% postoperative pulmonary complications versus 20% in the dynamic lung compliance group compared with the control group (P < 0.01). The serum Interleukin-10 concentrations at T5 in the dynamic lung compliance group were higher than those in the ventilation group (P = 0.046), and the serum Interleukin-1 concentrations at T5 and T6 in the dynamic lung compliance group were lower than those in the ventilation group (P < 0.01).ConclusionsIn patients undergoing video-assisted thoracoscopic lobectomy for lung resection with maximum dynamic compliance-guided positive end-expiratory pressure (PEEP), the incidence of postoperative pulmonary complications (PPCs) within 7 days was significantly lower compared to those receiving a PEEP of 5 cm H2O.Trial registrationThis study was registered at the Chinese Clinical Trials Registry on 04/07/2021 with registration number ChiCTR2100048201.

SummaryBackgroundWhile an association of the intraoperative driving pressure with postoperative pulmonary complications has been described before, it is uncertain whether the intraoperative mechanical power is associated with postoperative pulmonary complications.MethodsPosthoc analysis of two international, multicentre randomised clinical trials (ISRCTN70332574 and NCT02148692) conducted between 2011–2013 and 2014–2018, in patients undergoing open abdominal surgery comparing the effect of two different positive end–expiratory pressure (PEEP) levels on postoperative pulmonary complications. Time–weighted average dynamic driving pressure and mechanical power were calculated for individual patients. A multivariable logistic regression model adjusted for confounders was used to assess the independent associations of driving pressure and mechanical power with the occurrence of a composite of postoperative pulmonary complications, the primary endpoint of this posthoc analysis.FindingsIn 1191 patients included, postoperative pulmonary complications occurrence was 35.9%. Median time–weighted average driving pressure and mechanical power were 14·0 [11·0–17·0] cmH2O, and 7·6 [5·1–10·0] J/min, respectively. While driving pressure was not independently associated with postoperative pulmonary complications (odds ratio, 1·06 [95% CI 0·88–1·28]; p=0.534), the mechanical power had an independent association with the occurrence of postoperative pulmonary complications (odds ratio, 1·28 [95% CI 1·05–1·57]; p=0.016). These findings were independent of body mass index or the level of PEEP used, i.e., independent of the randomisation arm.InterpretationIn this merged cohort of surgery patients, higher intraoperative mechanical power was independently associated with postoperative pulmonary complications. Mechanical power could serve as a summary ventilatory biomarker for the risk for postoperative pulmonary complications in these patients, but our findings need confirmation in other, preferably prospective studies.FundingThe two original studies were supported by unrestricted grants from the European Society of Anaesthesiology and the Amsterdam University Medical Centers, Location AMC. For this current analysis, no additional funding was requested. The funding sources had neither a role in the design, collection of data, statistical analysis, interpretation of data, writing of the report, nor in the decision to submit the paper for publication.

Association between driving pressure and postoperative pulmonary complications in patients undergoing lung resection surgery: A randomised clinical trial

Editorial| May 2024 Mechanical Energy and Power: Time to Incorporate Them into Routine Monitoring of Mechanical Ventilation? Marcelo Gama de Abreu, M.D., M.Sc., Ph.D., D.E.S.A.I.C.; Marcelo Gama de Abreu, M.D., M.Sc., Ph.D., D.E.S.A.I.C. 1Division of Intensive Care and Resuscitation, Outcomes Research Consortium, and Division of Cardiothoracic Anesthesia, Department of Anesthesiology, Integrated Hospital-Care Institute, Cleveland Clinic, Cleveland, Ohio. https://orcid.org/0000-0002-3554-883X Search for other works by this author on: This Site PubMed Google Scholar Eduardo L. V. Costa, M.D., Ph.D. Eduardo L. V. Costa, M.D., Ph.D. Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information This editorial accompanies the article on p. 920. Accepted for publication January 25, 2024. Address correspondence to Dr. Gama de Abreu: Anesthesiology May 2024, Vol. 140, 877–880. https://doi.org/10.1097/ALN.0000000000004927 Connected Content Article: Association of Mechanical Energy and Power with Postoperative Pulmonary Complications in Lung Resection Surgery: A Post Hoc Analysis of Randomized Clinical Trial Data Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Cite Icon Cite Get Permissions Search Site Citation Marcelo Gama de Abreu, Eduardo L. V. Costa; Mechanical Energy and Power: Time to Incorporate Them into Routine Monitoring of Mechanical Ventilation?. Anesthesiology 2024; 140:877–880 doi: https://doi.org/10.1097/ALN.0000000000004927 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll PublicationsAnesthesiology Search Advanced Search Topics: mechanical energy, ventilation monitoring Mechanical ventilation with positive pressure is a cornerstone of practice in patients undergoing general anesthesia. However, it puts the lungs at risk of injury, so-called ventilator-induced lung injury.1 Notably, the risk of injury to the lung parenchyma when one-lung ventilation is conducted is higher than during two-lung ventilation.2 This in part explained by the fact that during one-lung ventilation, a higher respiratory rate (RR), positive end-expiratory pressure (PEEP), inspiratory flow, tidal volume (VT; when normalized to the lung area available for ventilation), and driving pressure (plateau pressure minus PEEP) are necessary to maintain adequate gas exchange as compared to two-lung ventilation. In other words, the amount of mechanical energy that is transferred per unit of time from the ventilator to the ventilated lung, so-called mechanical power, is usually higher during one-lung ventilation than during two-lung ventilation.3 This might have clinical implications for the practice of... You do not currently have access to this content.

BackgroundIntraoperative mechanical ventilation may influence postoperative pulmonary complications (PPCs). Current practice during thoracic surgery is not well described.MethodsThis is a post-hoc analysis of the prospective multicenter cross-sectional LAS VEGAS study focusing on patients who underwent thoracic surgery. Consecutive adult patients receiving invasive ventilation during general anesthesia were included in a one-week period in 2013. Baseline characteristics, intraoperative and postoperative data were registered. PPCs were collected as composite endpoint until the 5th postoperative day. Patients were stratified into groups based on the use of one lung ventilation (OLV) or two lung ventilation (TLV), endoscopic vs. non-endoscopic approach and ARISCAT score risk for PPCs. Differences between subgroups were compared using χ2 or Fisher exact tests or Student’s t-test. Kaplan–Meier estimates of the cumulative probability of development of PPC and hospital discharge were performed. Cox-proportional hazard models without adjustment for covariates were used to assess the effect of the subgroups on outcome.ResultsFrom 10,520 patients enrolled in the LAS VEGAS study, 302 patients underwent thoracic procedures and were analyzed. There were no differences in patient characteristics between OLV vs. TLV, or endoscopic vs. open surgery. Patients received VT of 7.4 ± 1.6 mL/kg, a PEEP of 3.5 ± 2.4 cmH2O, and driving pressure of 14.4 ± 4.6 cmH2O. Compared with TLV, patients receiving OLV had lower VT and higher peak, plateau and driving pressures, higher PEEP and respiratory rate, and received more recruitment maneuvers. There was no difference in the incidence of PPCs in OLV vs. TLV or in endoscopic vs. open procedures. Patients at high risk had a higher incidence of PPCs compared with patients at low risk (48.1% vs. 28.9%; hazard ratio, 1.95; 95% CI 1.05–3.61; p = 0.033). There was no difference in the incidence of severe PPCs. The in-hospital length of stay (LOS) was longer in patients who developed PPCs. Patients undergoing OLV, endoscopic procedures and at low risk for PPC had shorter LOS.ConclusionPPCs occurred frequently and prolonged hospital LOS following thoracic surgery. Proportionally large tidal volumes and high driving pressure were commonly used in this sub-population. However, large RCTs are needed to confirm these findings.Trial registrationThis trial was prospectively registered at the Clinical Trial Register (www.clinicaltrials.gov; NCT01601223; registered May 17, 2012.)

Measurement of inflammatory mediators in bronchoalveolar lavage (BAL) during lung resection surgery with periods of one-lung ventilation (OLV) has revealed an intense local pulmonary response. The role of each lung in the inflammation that occurs during this procedure has never been investigated. The primary objective of our study was to compare the inflammatory response in the dependent lung with that of the nondependent lung by measuring inflammatory markers in BAL. Our secondary objective was to assess the behaviour of these inflammatory mediators in patients with and without postoperative pulmonary complications (PPCs). A prospective, observational study. Department of Anaesthesiology in a university hospital. Forty-six consecutive patients undergoing lung resection surgery. BAL samples were taken from dependent and nondependent lung 10 min before initiating OLV and at the end of OLV (once two-lung ventilation was established). All patients were followed up until 30 days after surgery. The concentration of cytokines [interleukin (IL)-1, IL-2, IL-6, IL-10, tumour necrosis factor-alpha (TNF-α)], nitric oxide, carbon monoxide and matrix metalloproteinase 2 (MMP-2) was analysed in both lungs before and after OLV. PPCs were recorded. In BAL fluid, all measured biomarkers, apart from IL-10, were significantly greater (P < 0.05) at the end of OLV than those obtained before OLV, both for the dependent and nondependent lung. The increase in measured biomarkers was similar in both lungs. Eight patients developed PPC. Patients who developed PPC had higher levels of TNF-α (P < 0.05) in BAL from the nondependent lung before and after OLV than patients who did not have PPC. Patients who developed PPC had a smaller increase in MMP-2 levels (P < 0.05) in the dependent lung than patients who did not have PPC. In lung resection surgery, the inflammatory response is similar in both lungs. However, the greater increase in TNF-α levels in the nondependent lung and the smaller increase of MMP-2 concentration in the dependent lung may increase the susceptibility to develop PPC.