Surgical repair of acute type A aortic dissection: continuous pulmonary perfusion during retrograde cerebral perfusion prevents lung injury in a pilot study

Perioperative oxygenation impairment related to type a aortic dissection

Type A aortic dissection (TAAD) is a life-threatening disease with high mortality and poor prognosis, usually treated by surgery. There are many complications in its perioperative period, one of which is oxygenation impairment (OI). As a common complication of TAAD, OI usually occurs throughout the perioperative period of TAAD and requires prolonged mechanical ventilation (MV) and other supportive measures. The purpose of this article is to review the risk factors, mechanisms, and treatments of type A aortic dissection-related oxygenation impairment (TAAD-OI) so as to improve clinicians' knowledge about it. Among risk factors, elevated body mass index (BMI), prolonged extracorporeal circulation (ECC) duration, higher inflammatory cells and stored blood transfusion stand out. A reduced occurrence of TAAD-OI can be achieved by controlling these risk factors such as suppressing inflammatory response by drugs. As for its mechanism, it is currently believed that inflammatory signaling pathways play a major role in this process, including the HMGB1/RAGE signaling pathway, gut-lung axis and macrophage, which have been gradually explored and are expected to provide evidences revealing the specific mechanism of TAAD-OI. Numerous treatments have been investigated for TAAD-OI, such as nitric oxide (NO), continuous pulmonary perfusion/inflation, ulinastatin and sivelestat sodium, immunomodulation intervention and mechanical support. However, these measures are all aimed at postoperative TAAD-OI, and not all of the therapies have shown satisfactory effects. Treatments for preoperative TAAD-OI are not currently available because it is difficult to correct OI without correcting the dissection. Therefore, the best solution for preoperative TAAD-OI is to operate as soon as possible. At present, there is no specific method for clinical application, and it relies more on the experience of clinicians or learns from treatments of other diseases related to oxygenation disorders. More efforts should be made to understand its pathogenesis to better improve its treatments in the future.

Hotspots and development frontiers of postoperative complications of AD: Bibliometric analysis - a review

The research on the postoperative complications of aortic dissection (AD) has received great attention from scholars all over the world, and the number of research articles in this field has consistently increased year after year. However, no bibliometric reports have been published yet to analyze the scientific output and the current situation in this field. The Bibliometrix R-package, VOSviewer, and CiteSpace software were used to conduct a bibliometric analysis of the hotspots and development frontiers of AD. A total of 1242 articles were retrieved. The USA, China, and Japan had the highest number of publications. The five keywords with the highest frequency were "analysis," "incidence," "acute type," "graft," and "risk factor." The results also indicated that the research in related fields had shifted from surgical treatment and utilizing experience to the evidence-based exploration of risk factors and the construction of prediction models to help better manage postoperative complications of AD. This is the first bibliometric analysis of global publications on the postoperative complications of AD. The current research hotspots focus on three areas: common postoperative complications of AD, exploration of the related risk factors, and management of complications. Future research could focus on identifying risk factors through meta-analysis and using a multicenter database for AD as well as building relevant models to predict the development of complications to better facilitate the clinical management of AD patients.

Predictors and outcomes of postoperative tracheostomy in patients undergoing acute type A aortic dissection surgery

Background

Despite surgical advances, acute type A aortic dissection remains a life-threatening disease with high mortality and morbidity. Tracheostomy is usually used for patients who need prolonged mechanical ventilation in the intensive care unit (ICU). However, data on the risk factors for requiring tracheostomy and the impact of tracheostomy on outcomes in patients after Stanford type A acute aortic dissection surgery (AADS) are limited.

Methods

A retrospective single-institutional study including consecutive patients who underwent AADS between January 2016 and December 2019 was conducted. Patients who died intraoperatively were excluded. Univariate analysis and multivariate logistic regression analysis were used to identify independent risk factors for postoperative tracheostomy (POT). A nomogram to predict the probability of POT was constructed based on independent predictors and their beta-coefficients. The area under the receiver operating characteristic curve (AUC) was performed to assess the discrimination of the model. Calibration plots and the Hosmer–Lemeshow test were used to evaluate calibration. Clinical usefulness of the nomogram was assessed by decision curve analysis. Propensity score matching analysis was used to analyze the correlation between requiring tracheostomy and clinical prognosis.

Results

There were 492 patients included in this study for analysis, including 55 patients (11.2%) requiring tracheostomy after AADS. Compared with patients without POT, patients with POT experienced longer ICU and hospital stay and higher mortality. Age, cerebrovascular disease history, preoperative white blood cell (WBC) count and renal insufficiency, intraoperative amount of red blood cell (RBC) transfusion and platelet transfusion were identified as independent risk factors for POT. Our constructed nomogram had good discrimination with an AUC = 0.793 (0.729–0.856). Good calibration and clinical utility were observed through the calibration and decision curves, respectively. For better clinical application, we defined four intervals that stratified patients from very low to high risk for occurrence of POT.

Conclusions

Our study identified preoperative and intraoperative risk factors for POT and found that requiring tracheostomy was related to the poor outcomes in patients undergoing AADS. The established prediction model was validated with well predictive performance and clinical utility, and it may be useful for individual risk assessment and early clinical decision-making to reduce the incidence of tracheostomy.

Clinical investigation of nosocomial infections in adult patients after cardiac surgery

Nosocomial infections (NI) are common complications after cardiac surgery. To date, there have been few manuscripts investigating NI in the intensive care unit after cardiac surgery. Our study was designed to investigate the characteristics of the distribution of pathogenic bacteria, antibiotic resistance and risk factors for NI.A total of 1360 patients received standard postoperative care, including antibiotic prophylaxis. Microbiological examinations of sputum, blood, catheter tips and excrement were performed as clinically indicated to isolate pathogens. Thirty potential associated variables were collected and compared between the 2 different groups according to the development of NI using univariate and multivariate analyses.Eighty-nine patients (6.54%) acquired a microbiologically documented NI. There was a significant difference in mortality between the 2 groups with or without postoperative NI (23.60% vs 2.28%, P < .00). A total of 98 pathogens (73.13%) were isolated from sputum, 32 pathogens (23.88%) from blood and only 1 (0.75%) from urine. Three (2.24%) surgical site infections were detected, including 2 superficial surgical site infections and 1 mediastinitis. The most common pathogens were Gram-negative bacteria (78.36%), followed by Gram-positive bacteria (14.93%) and fungi (6.71%). The major pathogenic species had different levels of drug resistance, and most of them exhibited multidrug resistance. Six out of thirty variables were identified as independent risk factors for the development of NI, namely, duration of surgery, low cardiac output syndrome, continuous veno-venous hemofiltration, mechanical ventilation time, reintubation and tracheostomy.We analyzed the characteristics of the distribution of pathogens, antibiotic resistance and risk factors for NI in our center and provided some suggestions for clinical practice. In addition to antibiotic treatment, avoidance of risk factors and aggressive infection control measures may be crucial to stop or prevent outbreaks.

Lung Protection Strategies during Cardiopulmonary Bypass Affect the Composition of Blood Electrolytes and Metabolites-A Randomized Controlled Trial

Cardiac surgery with cardiopulmonary bypass (CPB) causes an acute lung ischemia-reperfusion injury, which can develop to pulmonary dysfunction postoperatively. This sub-study of the Pulmonary Protection Trial aimed to elucidate changes in arterial blood gas analyses, inflammatory protein interleukin-6, and metabolites of 90 chronic obstructive pulmonary disease patients following two lung protective regimens of pulmonary artery perfusion with either hypothermic histidine-tryptophan-ketoglutarate (HTK) solution or normothermic oxygenated blood during CPB, compared to the standard CPB with no pulmonary perfusion. Blood was collected at six time points before, during, and up to 20 h post-CPB. Blood gas analysis, enzyme-linked immunosorbent assay, and nuclear magnetic resonance spectroscopy were used, and multivariate and univariate statistical analyses were performed. All patients had decreased gas exchange, augmented inflammation, and metabolite alteration during and after CPB. While no difference was observed between patients receiving oxygenated blood and standard CPB, patients receiving HTK solution had an excess of metabolites involved in energy production and detoxification of reactive oxygen species. Also, patients receiving HTK suffered a transient isotonic hyponatremia that resolved within 20 h post-CPB. Additional studies are needed to further elucidate how to diminish lung ischemia-reperfusion injury during CPB, and thereby, reduce the risk of developing severe postoperative pulmonary dysfunction.

Lung Protection Strategies during Cardiopulmonary Bypass Affect the Composition of Bronchoalveolar Fluid and Lung Tissue in Cardiac Surgery Patients

Pulmonary dysfunction is among the most frequent complications to cardiac surgeries. Exposure of blood to the cardiopulmonary bypass (CPB) circuit with subsequent lung ischemia-reperfusion leads to the production of inflammatory mediators and increases in microvascular permeability. The study aimed to elucidate histological, cellular, and metabolite changes following two lung protective regimens during CPB with Histidine-Tryptophan-Ketoglutarate (HTK) enriched or warm oxygenated blood pulmonary perfusion compared to standard regimen with no pulmonary perfusion. A total of 90 patients undergoing CPB were randomized to receiving HTK, oxygenated blood or standard regimen. Of these, bronchoalveolar lavage fluid (BALF) and lung tissue biopsies were obtained before and after CPB from 47 and 25 patients, respectively. Histopathological scores, BALF cell counts and metabolite screening were assessed. Multivariate and univariate analyses were performed. Profound histological, cellular, and metabolic changes were identified in all patients after CPB. Histological and cellular changes were similar in the three groups; however, some metabolite profiles were different in the HTK patients. While all patients presented an increase in inflammatory cells, metabolic acidosis, protease activity and oxidative stress, HTK patients seemed to be protected against severe acidosis, excessive fatty acid oxidation, and inflammation during ischemia-reperfusion. Additional studies are needed to confirm these findings.

Oxygenation impairment after total arch replacement with a stented elephant trunk for type-A dissection

OBJECTIVE

To study the risk factors of oxygenation impairment in patients with type-A acute aortic dissection who underwent total arch replacement with a stented elephant trunk.

METHODS

In this study, 169 consecutive patients were enrolled who were diagnosed with type-A acute aortic dissection and underwent a total arch replacement procedure at the Qilu Hospital of Shandong University between January 2015 and February 2017. Postoperative oxygenation impairment was defined as arterial oxygen partial pressure/inspired oxygen fraction ≤ 200 with positive end expiratory pressure ≥ 5 cm H₂O that occurred within 72 hours of surgery. Perioperative clinical characteristics of all patients were collected and univariable analyses were performed. Risk factors associated with oxygenation impairment identified by univariable analyses were included in the multivariable regression analysis.

RESULTS

The incidence of postoperative oxygenation impairment was 48.5%. Postoperative oxygenation impairment was associated with prolonged mechanical ventilation time, intensive care unit stay, and hospital stay. Multivariable regression analysis demonstrated that body mass index (odds ratio [OR], 1.204; 95% confidence interval [CI], 1.065-1.361; P = .003), preoperative oxygenation impairment (OR, 9.768; 95% CI, 4.159-22.941; P < .001), preoperative homocysteine (OR, 1.080; 95% CI, 1.006-1.158; P = .032), circulatory arrest time (OR, 1.123; 95% CI, 1.044-1.207; P = .002), and plasma transfusion (OR, 1.002; 95% CI, 1.001-1.003; P = .002) were significantly associated with postoperative oxygenation impairment.

CONCLUSIONS

Postoperative oxygenation impairment is a common complication of surgery for type-A acute aortic dissection. Body mass index, preoperative oxygenation impairment, preoperative homocysteine, circulatory arrest time, and plasma transfusion were independent risk factors for oxygenation impairment after a total arch replacement procedure.

Pulmonary artery perfusion versus no perfusion during cardiopulmonary bypass for open heart surgery in adults

BACKGROUND

Available evidence has been inconclusive on whether pulmonary artery perfusion during cardiopulmonary bypass (CPB) is associated with decreased or increased mortality, pulmonary events, and serious adverse events (SAEs) after open heart surgery. To our knowledge, no previous systematic reviews have included meta-analyses of these interventions.

OBJECTIVES

To assess the benefits and harms of single-shot or continuous pulmonary artery perfusion with blood (oxygenated or deoxygenated) or a preservation solution compared with no perfusion during cardiopulmonary bypass (CPB) in terms of mortality, pulmonary events, serious adverse events (SAEs), and increased inflammatory markers for adult surgical patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, and advanced Google for relevant studies. We handsearched retrieved study reports and scanned citations of included studies and relevant reviews to ensure that no relevant trials were missed. We searched for ongoing trials and unpublished trials in the World Health Organization International Clinical Trials Registry Platform (ICTRP) and at clinicaltrials.gov (4 July 2017). We contacted medicinal firms producing preservation solutions to retrieve additional studies conducted to examine relevant interventions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared pulmonary artery perfusion versus no perfusion during CPB in adult patients (≧ 18 years).

DATA COLLECTION AND ANALYSIS

Two independent review authors extracted data, conducted fixed-effect and random-effects meta-analyses, and calculated risk ratios (RRs) or odds ratios (ORs) for dichotomous outcomes. For continuous data, we have presented mean differences (MDs) and 95% confidence intervals (CIs) as estimates of the intervention effect. To minimize the risk of systematic error, we assessed risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied Trial Sequential Analyses (TSAs). We used GRADE principles to assess the quality of evidence.

MAIN RESULTS

We included in this review four RCTs (210 participants) reporting relevant outcomes. Investigators randomly assigned participants to pulmonary artery perfusion with blood versus no perfusion during CPB. Only one trial included the pulmonary artery perfusion intervention with a preservation solution; therefore we did not perform meta-analysis. Likewise, only one trial reported patient-specific data for the outcome "pulmonary events"; therefore we have provided no results from meta-analysis. Instead, review authors added two explorative secondary outcomes for this version of the review: the ratio of partial pressure of oxygen in arterial blood (PaO₂) to fraction of inspired oxygen (FiO₂); and intubation time. Last, review authors found no comparable data for the secondary outcome inflammatory markers.The effect of pulmonary artery perfusion on all-cause mortality was uncertain (Peto OR 1.78, 95% CI 0.43 to 7.40; TSA adjusted CI 0.01 to 493; 4 studies, 210 participants; GRADE: very low quality). Sensitivity analysis of one trial with overall low risk of bias (except for blinding of personnel during the surgical procedure) yielded no evidence of a difference for mortality (Peto OR 1.65, 95% CI 0.27 to 10.15; 1 study, 60 participants). The TSA calculated required information size was not reached and the futility boundaries did not cross; thus this analysis cannot refute a 100% increase in mortality.The effect of pulmonary artery perfusion with blood on SAEs was likewise uncertain (RR 1.12, 95% CI 0.66 to 1.89; 3 studies, 180 participants; GRADE: very low quality). Data show an association between pulmonary artery perfusion with blood during CPB and a higher postoperative PaO₂/FiO₂ ratio (MD 27.80, 95% CI 5.67 to 49.93; 3 studies, 119 participants; TSA adjusted CI 5.67 to 49.93; GRADE: very low quality), although TSA could not confirm or refute a 10% increase in the PaO₂/FiO₂ ratio, as the required information size was not reached.

AUTHORS' CONCLUSIONS

The effects of pulmonary artery perfusion with blood during cardiopulmonary bypass (CPB) are uncertain owing to the small numbers of participants included in meta-analyses. Risks of death and serious adverse events may be higher with pulmonary artery perfusion with blood during CPB, and robust evidence for any beneficial effects is lacking. Future randomized controlled trials (RCTs) should provide long-term follow-up and patient stratification by preoperative lung function and other documented risk factors for mortality. One study that is awaiting classification (epub abstract with preliminary results) may change the results of this review when full study details have been published.

Impact of Presurgical Mild Acute Respiratory Distress Syndrome on Surgical Mortality After Surgical Repair of Acute Type A Aortic Dissection

To evaluate the impact of presurgical mild acute respiratory distress syndrome (ARDS) on surgical mortality in patients undergoing surgical repair of acute type A aortic dissection by means of deep hypothermic circulatory arrest (DHCA) in a single-center, retrospective study.From January 2011 to December 2015, 333 eligible patients were divided into either a mild-ARDS group (n = 136) or a no-ARDS group (n = 197). The definition of mild ARDS referred to the recent revision of ARDS definition (Berlin criteria). The surgical mortality and major postoperative morbidity were investigated and analyzed.A total of 136 patients developed presurgical mild ARDS, with an incidence of 40.8%. No significant difference emerged between the 2 groups in major postoperative morbidity except for pulmonary complications. Multivariate logistic regression displayed that the risk of postoperative pulmonary complications in patients with presurgical mild ARDS was 4.25 times that in patients without presurgical ARDS (OR = 4.25, 95% CI 2.05-7.72). Twenty-four patients died after surgery, with significantly higher surgical mortality in the mild-ARDS group compared with the no-ARDS group (12.5% versus 3.6%, P = 0.002). Kaplan-Meier curves showed a poor surgical survival in the mild-ARDS group (χ²=12.958, Log-Rank P < 0.001). And Cox regression revealed the hazard ratio for surgical mortality in the mild-ARDS group compared with the no-ARDS group was 2.52 (95%CI 1.41-5.32, P = 0.016).Presurgical mild ARDS increased postoperative respiratory morbidity, and then increased surgical mortality after surgical repair of acute type A aortic dissection by means of DHCA.

Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD: a randomised clinical trial

Introduction

Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery.

Methods

90 patients were randomised to receive pulmonary artery perfusion during CPB with either oxygenated blood (n=30) or histidine-tryptophan-ketoglutarate (HTK) solution (n=29) compared with no pulmonary perfusion (n=31). The coprimary outcomes were the inverse oxygenation index compared at 21 hours after starting CPB and longitudinally in a mixed-effects model (MEM). Secondary outcomes were tracheal intubation time, serious adverse events, mortality, days alive outside the intensive care unit (ICU) and outside the hospital.

Results

21 hours after starting CPB patients receiving pulmonary artery perfusion with normothermic oxygenated blood had a higher oxygenation index compared with no pulmonary perfusion (mean difference (MD) 0.94; 95% CI 0.05 to 1.83; p=0.04). The blood group had also a higher oxygenation index both longitudinally (MEM, p=0.009) and at 21 hours (MD 0.99; CI 0.29 to 1.69; p=0.007) compared with the HTK group. The latest result corresponds to a difference in the arterial partial pressure of oxygen of 23 mm Hg with a median fraction of inspired oxygen of 0.32. Yet the blood or HTK groups did not demonstrate a longitudinally higher oxygenation index compared with no pulmonary perfusion (MEM, p=0.57 and 0.17). Similarly, at 21 hours there was no difference in the oxygenation index between the HTK group and those no pulmonary perfusion (MD 0.06; 95% CI −0.73 to 0.86; p=0.87). There were no statistical significant differences between the groups for the secondary outcomes.

Discussion

Pulmonary artery perfusion with normothermic oxygenated blood during cardiopulmonary bypass appears to improve postoperative oxygenation in patients with COPD undergoing cardiac surgery. Pulmonary artery perfusion with hypothermic HTK solution does not seem to improve postoperative oxygenation.

Trial registration number

NCT01614951; Pre-results.

Lung preconditioning in anesthesia: Review of the literature

Lung injury can arise during or after anesthesia and can lead to a complicated postoperative course with great implications for the patient. Unfortunately, treatment of acute lung injury is at the moment mainly supportive and rates of recovery have not really improved in the recent years. In many cases, lung injury can be anticipated and preventive measures seem possible. This represents a unique challenge to the anesthesiologist, as some new opportunities to reduce the frequency and/or severity of lung injury seem now available. These chances may arise from the potency of preconditioning the lungs before the main injury, with smaller injurious insults. Although preconditioning began to be applicated first on the myocardium, experimental studies have shown potentially beneficial results also for the lungs. This review summarizes the main methods of lung preconditioning that have been tried in experimental studies in the literature and the main mechanisms that are perhaps involved. Emphasis is given in the two main methods of preconditioning that seem readily applicable in the clinical praxis, that is ischemic preconditioning, as well as preconditioning with volatile anesthetics. The few, but interesting clinical studies are also summarized and the future research points in this evolving field of anesthesia are stressed.

Risk factors for postoperative hypoxemia in patients undergoing Stanford A aortic dissection surgery

Background

The purpose of this study is to identify the risk factors for postoperative hypoxemia in patients with Stanford A aortic dissection surgery and their relation to clinical outcomes.

Methods

Clinical records of 186 patients with postoperative hypoxemia in Stanford A aortic dissection were analyzed retrospectively. The patients were divided into two groups by postoperative oxygen fraction (PaO2/FiO2):hypoxemia group (N=92) and non-hypoxemia group (N=94).

Results

We found that the incidence of postoperative hypoxemia was 49.5%. Statistical analysis by t-test and χ2 indicated that acute onset of the aortic dissection (p=0.000), preoperative oxygen fraction (PaO2/FiO2) ≤200 mmHg(p=0.000), body mass index (p=0.008), circulatory arrest (CA) time (p=0.000) and transfusion more than 3000 ml(p=0.000) were significantly associated with postoperative hypoxemia. Multiple logistic regression analysis showed that preoperative hypoxemia, CA time and transfusion more than 3000 ml were independently associated with postoperative hypoxemia in Stanford A aortic dissection.

Conclusion

Our results suggest that postoperative hypoxemia is a common complication in patients treated by Stanford A aortic dissection surgery. Preoperative oxygen fraction lower than 200 mmHg, longer CA time and transfusion more than 3000 ml are predictors of postoperative hypoxemia in Stanford A aortic dissection.

Analysis of the risk factors of postoperative respiratory dysfunction of type A aortic dissection and lung protection

AIM

Retrospectively to analyze the risk factors of postoperative respiratory dysfunction (RD) in 196 patients with type A dissection operated on with cerebral perfusion and a lower body hypothermia circulatory arrest (HCA) and to investigate the method of the lung protection.

METHODS

From January 2005 to April 2008, 196 patients with type A dissection underwent surgical repair with cerebral perfusion and HCA. There were 142 male patients and 54 female patients, with ages from 17 to 78 years. Antegrade selective cerebral perfusion (SCP) through the axillary artery was performed for 168 patients and retrograde cerebral perfusion (RCP) from the superior vena cava for 28 patients. All the factors underwent univariate and multivariate analysis.

RESULTS

Mean cardiopulmonary bypass (CPB) duration was (186+/-56) minutes and mean cerebral perfusion time was (35+/-15) minutes; mean HCA time was (39+/-14) minutes. Postoperative RD was detected in 26 patients (13.3%). Multivariate analysis showed that the longer duration of circulatory arrest (CA), P=0.008, OR=1.048, and the higher temperature in the bladder during CA, P=0.002, OR=1.614, were independent risk factors of postoperative RD. There was a higher mortality (23.1%, P=0.025) in patients with postoperative RD when compared with the other patients.

CONCLUSION

The longer duration of CA and the higher temperature in the bladder during CA were found to be the independent risk factors of postoperative RD after type A aortic dissection surgery. Attention should be paid to lung protection for these patients and the adjunct of continuing descending aortic perfusion and cerebral perfusion should be a safe and feasible procedure and it would be valuable to perform a prospective trial.

Risk Factors for Hypoxemia After Surgery for Acute Type A Aortic Dissection

PURPOSE

Postoperative hypoxemia is a frequent complication of surgery for acute type A aortic dissection. We tried to determine the factors associated with postoperative hypoxemia.

METHODS

Between 1997 and 2003, 114 patients underwent surgery for acute type A aortic dissection. Multivariate logistic regression analysis was done to identify the independent predictors of postoperative hypoxemia, defined by an arterial partial oxygen/inspired oxygen fraction (PaO(2)/FiO(2)) ratio of 200 or lower.

RESULTS

The overall in-hospital mortality was 6.1% (7 of 114 patients), being 5.2% in the hypoxemia group and 6.9% in the non-hypoxemia group. The ventilation time and intensive care unit stay were significantly longer in the hypoxemia group than in the non-hypoxemia group (P = 0.0044, P = 0.038, respectively). Logistic regression identified the following variables as predictors for postoperative hypoxemia: body mass index > or = 25 (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.1-15.01; P < 0.001), preoperative PaO(2)/FiO(2) ratio < or = 300 (OR, 2.6; 95% CI, 1.09-6.13; P = 0.031), and the volume of transfused blood (OR, 1.08; 95% CI, 1.01-1.18; P = 0.037).

CONCLUSIONS

Initiating early treatment for hypoxemia and reducing the volume of blood transfused intraoperatively may improve the postoperative clinical course of obese patients with preoperative hypoxemia.