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Economic recession has dire consequences on overall health. None have explored the impact of economic crisis (EC) on infective endocarditis (IE) mortality. We conducted a retrospective, nationwide, temporal trend study analyzing mortality trends by age, sex, and adverse outcomes in patients diagnosed with IE in Spain from 1997 to 2014. Data were divided into two subperiods: pre-EC (January 1997-August 2008) and post-EC (September 2008-December 2014). A total of 25 952 patients presented with IE. The incidence increased from 301.4 to 365.1 per 10 000 000 habitants, and the mortality rate rose from 24.3% to 28.4%. Those aged >75 years experienced more adverse outcomes. Complications due to sepsis, shock, acute kidney injury requiring dialysis, and heart failure increased after the EC onset, and expenditures soared to €16 216. Expenditure per community was related to mortality ( P

Producción Científica, Background: procalcitonin is a valuable marker in the diagnosis of bacterial infections; however, the impairment of renal function can influence its diagnostic precision. The objective of this study is to evaluate the differential behaviour of procalcitonin, as well as its usefulness in the diagnosis of postoperative pulmonary infection after cardiac surgery, depending on the presence or absence of impaired renal function. Materials and methods: A total of 805 adult patients undergoing cardiac surgery with extracorporeal circulation (CBP) were prospectively recruited, comparing the behaviour of biomarkers between the groups with and without postoperative pneumonia and according to the presence or absence of renal dysfunction. Results: Pulmonary infection was diagnosed in 42 patients (5.21%). In total, 228 patients (28.32%) presented postoperative renal dysfunction. Procalcitonin was significantly higher in infected patients, even in the presence of renal dysfunction. The optimal procalcitonin threshold differed markedly in patients with renal dysfunction compared to patients without renal dysfunction (1 vs. 0.78 ng/mL p < 0.05). The diagnostic accuracy of procalcitonin increased significantly when the procalcitonin threshold was adapted to renal function. Conclusions: Procalcitonin is an accurate marker of postoperative infection in cardiac surgery, even in the presence of renal dysfunction. Renal function is an important determinant of procalcitonin levels and, therefore, its diagnostic thresholds must be adapted in the presence of renal dysfunction., Instituto de Salud Carlos III - (grant COV20/00491, PI18/01238, CIBERINFEC CB21/13/00051), Junta de Castilla y León - (grant VA321P18, GRS 1922/A/19, GRS 2057/A/19), Junta de Castilla y León, Consejería de Educación - (grant VA256P20), Fundación Ramón Areces - (grant CIVP19A5953), Instituto de Salud Carlos III y Fondo Europeo de Desarrollo Regional (FEDER)/Fondo Social Europeo - (grant CM20/00138)

Producción Científica, Pneumonia is the main cause of hospital admission in COVID-19 patients. We aimed to perform an extensive characterization of clinical, laboratory, and cytokine profiles in order to identify poor outcomes in COVID-19 patients. Methods: A prospective and consecutive study involving 108 COVID-19 patients was conducted between March and April 2020 at Hospital Clínico Universitario de Valladolid (Spain). Plasma samples from each patient were collected after emergency room admission. Forty-five serum cytokines were measured in duplicate, and clinical data were analyzed using SPPS version 25.0. Results: A multivariate predictive model showed high hepatocyte growth factor (HGF) plasma levels as the only cytokine related to intubation or death risk at hospital admission (OR = 7.38, 95%CI—(1.28–42.4), p = 0.025). There were no comorbidities included in the model except for the ABO blood group, in which the O blood group was associated with a 14-fold lower risk of a poor outcome. Other clinical variables were also included in the predictive model. The predictive model was internally validated by the receiver operating characteristic (ROC) curve with an area under the curve (AUC) of 0.94, a sensitivity of 91.7% and a specificity of 95%. The use of a bootstrapping method confirmed these results. Conclusions: A simple, robust, and quick predictive model, based on the ABO blood group, four common laboratory values, and one specific cytokine (HGF), could be used in order to predict poor outcomes in COVID-19 patients., Instituto de Salud Carlos III - ( Proyecto COV20/00491), Consejeria de Educación de Castilla y León - (Proyecto VA256P20), Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (Proyecto EDU/1100/2017)

Background Despite growing interest in treatment strategies that limit oxygen exposure in ICU patients, no studies have compared conservative oxygen with standard oxygen in postsurgical patients with sepsis/septic shock, although there are indications that it may improve outcomes. It has been proven that high partial pressure of oxygen in arterial blood (PaO2) reduces the rate of surgical-wound infections and mortality in patients under major surgery. The aim of this study is to examine whether PaO2 is associated with risk of death in adult patients with sepsis/septic shock after major surgery. Methods We performed a secondary analysis of a prospective observational study in 454 patients who underwent major surgery admitted into a single ICU. Patients were stratified in two groups whether they had hyperoxemia, defined as PaO2 > 100 mmHg (n = 216), or PaO2 ≤ 100 mmHg (n = 238) at the day of sepsis/septic shock onset according to SEPSIS-3 criteria maintained during 48 h. Primary end-point was 90-day mortality after diagnosis of sepsis. Secondary endpoints were ICU length of stay and time to extubation. Results In patients with PaO2 ≤ 100 mmHg, we found prolonged mechanical ventilation (2 [8] vs. 1 [4] days, p p p p p = 0.008). Hyperoxemia was associated with higher probability of 90-day survival in a multivariate analysis (OR 0.61, 95%CI: 0.39–0.95, p = 0.029), independent of age, chronic renal failure, procalcitonin levels, and APACHE II score > 19. These findings were confirmed when patients with severe hypoxemia at the time of study inclusion were excluded. Conclusions Oxygenation with a PaO2 above 100 mmHg was independently associated with lower 90-day mortality, shorter ICU stay and intubation time in critically ill postsurgical sepsis/septic shock patients. Our findings open a new venue for designing clinical trials to evaluate the boundaries of PaO2 in postsurgical patients with severe infections.

Respiratory viruses are part of the normal microbiota of the respiratory tract, which sometimes cause infection with/without respiratory insufficiency and the need for hospital or ICU admission. The aim of this study is to determine the prevalence of respiratory viruses in nontransplanted postoperative septic patients as well as lymphocyte count influence in their presence and its relationship to mortality. 223 nontransplanted postsurgical septic patients were recruited on the Intensive Care Unit (ICU) at Hospital Clínico Universitario de Valladolid prior to the SARS-COV-2 pandemic. Patients were split into 2 groups according to the presence/absence of respiratory viruses. Multivariate logistic regression analysis was used to identify independent factors related to positive respiratory virus PCR test. Respiratory viruses were isolated in 28.7% of patients. 28-day mortality was not significantly different between virus-positive and virus-negative groups. Logistic regression analysis revealed that lymphocyte count ≤ 928/µl is independently associated with a positive PCR result [OR 3.76, 95% CI (1.71-8.26), P = .001] adjusted by platelet count over 128,500/µL [OR 4.27, 95% CI (1.92-9.50) P.001] and the presence of hypertension [OR 2.69, 95% CI (1.13-6.36) P = .025] as confounding variables. Respiratory viruses' detection by using PCR in respiratory samples of nontransplanted postoperative septic patients is frequent. These preliminary results revealed that the presence of lymphopenia on sepsis diagnosis is independently associated to a positive virus result, which is not related to a higher 28-day mortality.

Diagnosis of cardiac surgery-associated acute kidney injury (CSA-AKI), a syndrome of sudden renal dysfunction occurring in the immediate post-operative period, is still sub-optimal. Standard CSA-AKI diagnosis is performed according to the international criteria for AKI diagnosis, afflicted with insufficient sensitivity, specificity, and prognostic capacity. In this article, we describe the limitations of current diagnostic procedures and of the so-called injury biomarkers and analyze new strategies under development for a conceptually enhanced diagnosis of CSA-AKI. Specifically, early pathophysiological diagnosis and patient stratification based on the underlying mechanisms of disease are presented as ongoing developments. This new approach should be underpinned by process-specific biomarkers including, but not limited to, glomerular filtration rate (GFR) to other functions of renal excretion causing GFR-independent hydro-electrolytic and acid-based disorders. In addition, biomarker-based strategies for the assessment of AKI evolution and prognosis are also discussed. Finally, special focus is devoted to the novel concept of pre-emptive diagnosis of acquired risk of AKI, a premorbid condition of renal frailty providing interesting prophylactic opportunities to prevent disease through diagnosis-guided personalized patient handling. Indeed, a new strategy of risk assessment complementing the traditional scores based on the computing of risk factors is advanced. The new strategy pinpoints the assessment of the status of the primary mechanisms of renal function regulation on which the impact of risk factors converges, namely renal hemodynamics and tubular competence, to generate a composite and personalized estimation of individual risk.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a recognized and serious complication and one of the stronger risk factors for mortality in patients undergoing cardiac surgery [...]

Producción Científica, Interferon lambda 3 (IFNL3, previously called IL-28B) is a cytokine with effects against viral and bacterial pathogens. We aimed to analyze the IFNL3 rs12980275 SNP in patients who underwent major surgery, in order to establish its relationship with susceptibility to septic shock and septic shock-related death in these patients. We performed a case-control study on 376 patients to establish the association between IFNL3 rs12980275 SNP and the susceptibility to develop septic shock. Besides, we performed a longitudinal study among 172 septic shock patients using survival analysis with one censoring point of 28-days mortality. The IFNL3 rs12980275 polymorphism was genotyped by Agena Bioscience's MassARRAY platform. IFNL3 rs12980275 polymorphism was not associated with higher susceptibility to infection and septic shock development. Regarding survival analysis, the Kaplan–Meier analysis showed that patients with IFNL3 rs12980275 AA genotype had higher survival than patients with GG genotype (p = 0.003). The Cox regression analysis adjusted by the most relevant clinical and epidemiological characteristics showed that the GG genotype (recessive model) and the presence of the G allele (additive model) were associated with higher risk of death [adjusted hazard ratio (aHR) = 2.15, p = 0.034; aHR = 1.50, p = 0.030, respectively]. In conclusion, IFNL3 rs12980275 polymorphism was associated with septic shock-related death in patients who underwent major surgery. The A allele was linked to protection, and the G allele was associated with an increased risk of death. This is a first preliminary study that suggests for the first time a role of IFNL3 polymorphisms in the prognosis of septic shock., Instituto de Salud Carlos III (grants PI15/01451, CP17CIII/00007 and CP14CIII/00010), Junta de Castilla y León (grants GR463/A/10 and GR773/A/13), PFIZER (grant CT25-ESP01-01)

Producción Científica, Acute kidney injury (AKI) is a widely held concern related to a substantial burden of morbidity, mortality and expenditure in the healthcare system. AKI is not a simple illness but a complex conglomeration of syndromes that often occurs as part of other syndromes in its wide clinical spectrum of the disease. Genetic factors have been suggested as potentially responsible for its susceptibility and severity. As there is no current cure nor an effective treatment other than generally accepted supportive measures and renal replacement therapy, updated knowledge of the genetic implications may serve as a strategic tactic to counteract its dire consequences. Further understanding of the genetics that predispose AKI may shed light on novel approaches for the prevention and treatment of this condition. This review attempts to address the role of key genes in the appearance and development of AKI, providing not only a comprehensive update of the intertwined process involved but also identifying specific markers that could serve as precise targets for further AKI therapies.

La injuria o lesión renal aguda (LRA) es una complicación frecuente en el post-operatorio de cirugía cardíaca y se asocia a un incremento de la morbimortalidad. El diagnostico precoz es fundamental en el abordaje de esta entidad para iniciar tempranamente medidas preventivas. El objetivo de este estudio fue diseñar una escala de predicción postoperatoria de LRA no dialítica, en pacientes con función renal previa normal operados de cirugía cardiaca con circulación extracorpórea. Material y métodos, Departamento de Cirugía, Oftalmología, Otorrinolaringología y Fisioterapia

Producción Científica, Acute kidney injury (AKI) is a severe complication and a strong risk factor for death in patients undergoing cardiac surgery,1, 2 so much so that the term cardiac surgery–associated acute kidney injury (CSA-AKI) has been coined, and establishing a predictive model for CSA-AKI has been the focus of past research. Various predictive models have been established to predict AKI, such as the AKI after cardiac surgery score, the Cleveland Clinic score, the Mehta score, and the simplified renal index score. However, the discrimination and calibration predictive value for each of these models is not convincing, and therefore these models are barely acceptable.

Producción Científica, Goal-directed therapy based on brain-oxygen saturation (bSo2) is controversial and hotly debated. While meta-analyses of aggregated data have shown no clinical benefit for brain near-infrared spectroscopy (NIRS)-based interventions after cardiac surgery, no network meta-analyses involving both major cardiac and noncardiac procedures have yet been undertaken. Randomized controlled trials involving NIRS monitoring in both major cardiac and noncardiac surgery were included. Aggregate-level data summary estimates of critical outcomes (postoperative cognitive decline (POCD)/postoperative delirium (POD), acute kidney injury, cardiovascular events, bleeding/need for transfusion, and postoperative mortality) were obtained. NIRS was only associated with protection against POCD/POD in cardiac surgery patients (pooled odds ratio (OR)/95% confidence interval (CI)/I2/number of studies (n): 0.34/0.14–0.85/75%/7), although a favorable effect was observed in the analysis, including both cardiac and noncardiac procedures. However, the benefit of the use of NIRS monitoring was undetectable in Bayesian network meta-analysis, although maintaining bSo2 > 80% of the baseline appeared to have the most pronounced impact. Evidence was imprecise regarding acute kidney injury, cardiovascular events, bleeding/need for transfusion, and postoperative mortality. There is evidence that brain NIRS-based algorithms are effective in preventing POCD/POD in cardiac surgery, but not in major noncardiac surgery. However, the specific target bSo2 threshold has yet to be determined., Junta de Castilla y León (project VA161G18)

We intended to assess how acute kidney injuy impacts on procalcitonin levels in cardiac surgery patients, with or without infection, and whether procalcitonin might be used as a biomarker of infection in acute kidney injuy.A case-control study was designed which included patients that had had cardiac surgery between January 2011 and January 2015. Every patient developing severe sepsis or septic shock (n = 122; 5.5%) was enrolled. In addition, consecutive cardiac surgery patients during 2013 developing systemic inflammatory response syndrome (n = 318) were enrolled. Those recruited 440 patients were divided into 2 groups, according to renal function.Median procalcitonin levels were significantly higher during the 10 postoperative days in the acute kidney injury patients. Regression analysis showed that postoperatory day, creatinine, white blood cells and infection were significantly (P.0001) associated to serum procalcitonin level. In patients with creatinine ≥2, median procalcitonin levels were similar in infected and non-infected patients. Only when creatinine was less than 2 mg/L, the median procalcitonin levels were significantly higher in patients with infection, as compared to those with no infection.In acute kidney injuy patients, high procalcitonin levels are a marker of acute kidney injuy but will not be able to differentiate infected from non-infected patients.

Producción Científica, Purpose: Acute kidney injury (AKI) is a frequent complication after cardiac surgery and is associated with increased mortality. The aim was to design a nondialytic AKI score in patients with previously normal renal function undergoing cardiac surgery. Methods: Data were collected on 909 patients who underwent cardiac surgery with cardiopulmonary bypass between 2012 and 2014. A total of 810 patients fulfilled the inclusion criteria. Patients were classified as having AKI based on the RIFLE criteria. Postoperative AKI occurred in 137 patients (16.9%). Several parameters were recorded preoperatively, intraoperatively, and at intensive care unit admission, looking for a univariate andmultivariate associationwith AKI risk. A second data set of 741 patients, from2 different hospitals,was recorded as a validation cohort. Results: Four independent risk factors were included in the CRATE score: creatinine (odds ratio [OR], 9.66; 95% confidence interval [CI], 4.77-19.56; P b .001), EuroSCORE (OR, 1.40; CI, 1.29-1.52; P b .001), lactate (OR, 1.03; CI, 1.01- 1.04; P b .001), and cardiopulmonary bypass time (OR, 1.01; CI, 1.01-1.02; P b .001). The accuracy of the model was good, with an area under the curve of 0.89 (CI, 0.85-0.92). The CRATE score retained good discrimination in validation cohort, with an area under the curve of 0.81 (95% CI, 0.78-0.85). Conclusions: CRATE score is an accurate and easy to calculate risk score that uses affordable andwidely available variables in the routine care surgical patients.

Producción Científica, Objective: The aims of this study were to identify the risk factors associated with acute kidney injury (AKI) after isolated surgical revascularization with cardiopulmonary bypass and to develop a model to predict the appearance of postoperative AKI. Methods: A total of 435 adult patients who underwent primary isolated coronary artery bypass graft (CABG) surgery, from 2012 to 2016, in the Clinic University Hospital of Valladolid (Spain) were enrolled. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Data were collected from hospital electronic medical records. Multiple logistic regression analysis was used to identify risk factors. Results: The prevalence of AKI was 12.4%. Multivariate analysis identified age (odds ratio [OR], 1.056; 95% confidence interval [CI], 1.016-1.098; P=0.005), hypertension (OR, 3.078; 95% CI, 1.151-8.230; P=0.018), low ejection fraction (EF) (OR, 6.785; 95% CI, 2.080-22.135; P=0.001), estimated glomerular filtration rate (eGFR) (OR, 1.017; 95% CI, 1.005-1.028; P=0.014), EuroSCORE II (OR, 1.049; 95% CI, 1.004-1.096; P=0.033), and no intake of calcium-channel blockers (CCB) (OR, 4.892; 95% CI, 1.496-16.025; P=0.022) as risk factors for AKI. These risk factors were included in a model to predict postoperative AKI with an area under a receiver operating characteristic curve of 0.783±0.036 (95% CI, 0.713-0.854; P

Objective Acute kidney injury is a severe complication and one of the stronger risk factors for death in patients undergoing cardiac surgery. The relationship between postoperative brain oxygen saturation and kidney oxygen saturation with acute kidney injury in adults undergoing cardiac surgery has not been determined. We designed a single-center prospective study to determine if the continuous monitoring of postoperative brain oxygen saturation and kidney oxygen saturation could predict postoperative acute kidney injury. Methods We conducted a prospective open cohort study from January to September 2017. The primary outcome was postoperative acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria. Brain oxygen saturation and kidney oxygen saturation, the metrics of which were area measurements (%-min), were recorded during the surgery and the first 48 hours after the cardiac procedure. Receiver operating characteristic curve analysis was used to evaluate the predictive power of kidney oxygen saturation for acute kidney injury. Results A total of 121 consecutive patients were enrolled. Thirty-five patients (28.9%) developed acute kidney injury. Brain oxygen saturation showed no statistical difference in both groups; however, kidney oxygen saturation was related to acute kidney injury (P = .001). Receiver operating characteristic curve analysis showed that kidney oxygen saturation could predict the risk of acute kidney injury. Kidney oxygen saturation less than 65% (area under the curve-receiver operating characteristic, 0.679 ± 0.054, 95% confidence interval, 0.573-0.785, P = .002) and 20% decrease from baseline (area under the curve-receiver operating characteristic, 0.639 ± 0.059, 95% confidence interval, 0.523-0.755, P = .019) showed the better performance, respectively. Conclusions Postoperative kidney oxygen saturation is related to the development of cardiac surgery–associated acute kidney injury. Continuous kidney saturation monitoring might be a promising, noninvasive tool for predicting acute kidney injury during the postoperative period for adult patients after cardiac surgery.

Producción Científica, We read the article by Takaki et al. [1] with great interest, owing to the fact that the onset of kidney failure in the postoperative period following cardiac surgery is, perhaps, the most common complication and one that is linked to high morbidity and mortality and increased hospital stays, both in the ICU and generally; it is an independent predictor of mortality following cardiac surgery [2,3]. Several authors have highlighted the role of creatinine as a predictive factor in the development of acute kidney injury (AKI). The majority of studies are based on the analysis of raised creatinine levels, and do not take into account reductions to the figures due to haemodilution, a consequence of the priming of extracorporeal circulation (ECC). In this sense, the analysis of these authors is very interesting, as it looks at the correlation between changes in creatinine levels and haematocrit [1]. The issue of optimum haematocrit levels that should be maintained during ECC in order to reduce the incidence of AKI is widely debated

After Publication of the original article [1] it has been brought to our attention that none of the tables referred to in the text have been included in the article. Tables 1, ​,2,2, ​,3,3, ​,4,4, ​,5,5, ​,66 and ​and77 are now displayed below. Table 1 Patient population profile (Survivors and non-survivors) Table 2 Parameters at the admission to the intensive care unit in survivors and non-survivors Table 3 Logistic regression model: risk factors for 90-day In-Hospital Mortality Table 4 A new system to predict operative mortality in patients undergoing cardiac surgery: POCAS score Table 5 Development series: predictive function of POCAS score scale for 90-day In- Hospital Mortality (Logistic regression) Table 6 Operative risk categories with corresponding cumulative risk score for 90-day In-Hospital Mortality after cardiac surgery for the risk groups calculated from the roc curve, cumulative risk score* Table 7 Validity of Additive EuroSCORE, Logistic EuroSCORE, ACEF, SOFA, SAP II, APACHE II, and POCAS to predict the 90-day In-Hospital Mortality rate after cardiac surgery with CEC

Producción Científica, The risk of mortality in cardiac surgery is generally evaluated using preoperative risk-scale models. However, intraoperative factors may change the risk factors of patients, and the organism functionality parameters determined upon ICU admittance could therefore be more relevant in deciding operative mortality. The goals of this study were to find associations between the general parameters of organism functionality upon ICU admission and the operative mortality following cardiac operations, to develop a Post Cardiac Surgery (POCAS) Scale to define operative risk categories and to validate an operative mortality risk score. Methods: We conducted a prospective study, including 920 patients who had undergone cardiac surgery with cardiopulmonary bypass. Several parameters recorded on their ICU admission were explored, looking for a univariate and multivariate association with in-hospital mortality (90 days). In-hospital mortality was 9%. Four independent factors were included in the POCAS mortality risk model: mean arterial pressure, bicarbonate, lactate and the International Normalized Ratio (INR). The POCAS scale was compared with four other risk scores in the validation series. Results: In-hospital mortality (90 days) was 9%. Four independent factors were included in the POCAS mortality risk model: mean arterial pressure, bicarbonate ratio, lactate ratio and the INR. The POCAS scale was compared with four other risk scores in the validation series. Discriminatory power (accuracy) was defined with a receiver-operating characteristics (ROC) analysis. The best accuracy in predicting in-hospital mortality (90 days) was achieved by POCAS. The areas under the ROC curves of the different systems analyzed were 0.890 (POCAS), followed by 0.847 (Simplified Acute Physiology Score (SAP II)), 0.825 (Sepsis-related Organ Failure Assessment (SOFA)), 0.768 (Acute Physiology and Chronic Health Evaluation (APACHE II)), 0.754 (logistic EuroSCORE), 0.714 (standard EuroSCORE) and 0.699 (Age, Creatinine, Ejection Fraction (ACEF) score). Conclusions: Our new system to predict the operative mortality risk of patients undergoing cardiac surgery is better than others used for this purpose (SAP II, SOFA, APACHE II, logistic EuroSCORE, standard EuroSCORE, and ACEF score). Moreover, it is an easy-to-use tool since it only requires four risk factors for its calculation., Junta de Castilla y León (grant GRS 463/A/10), Ministerio de Sanidad, Consumo y Bienestar Social (grant RD06/0001/0020)

BackgroundRespiratory complications are an important cause of postoperative morbidity. We aimed to investigate whether continuous positive airway pressure (CPAP) administered immediately after major abdominal surgery could prevent postoperative morbidity.MethodsPRISM was an open-label, randomised, phase 3 trial done at 70 hospitals across six countries. Patients aged 50 years or older who were undergoing elective major open abdominal surgery were randomly assigned (1:1) to receive CPAP within 4 h of the end of surgery or usual postoperative care. Patients were randomly assigned using a computer-generated minimisation algorithm with inbuilt concealment. The primary outcome was a composite of pneumonia, endotracheal re-intubation, or death within 30 days after randomisation, assessed in the intention-to-treat population. Safety was assessed in all patients who received CPAP. The trial is registered with the ISRCTN registry, ISRCTN56012545.FindingsBetween Feb 8, 2016, and Nov 11, 2019, 4806 patients were randomly assigned (2405 to the CPAP group and 2401 to the usual care group), of whom 4793 were included in the primary analysis (2396 in the CPAP group and 2397 in the usual care group). 195 (8·1%) of 2396 patients in the CPAP group and 197 (8·2%) of 2397 patients in the usual care group met the composite primary outcome (adjusted odds ratio 1·01 [95% CI 0·81-1·24]; p=0·95). 200 (8·9%) of 2241 patients in the CPAP group had adverse events. The most common adverse events were claustrophobia (78 [3·5%] of 2241 patients), oronasal dryness (43 [1·9%]), excessive air leak (36 [1·6%]), vomiting (26 [1·2%]), and pain (24 [1·1%]). There were two serious adverse events: one patient had significant hearing loss and one patient had obstruction of their venous catheter caused by a CPAP hood, which resulted in transient haemodynamic instability.InterpretationIn this large clinical effectiveness trial, CPAP did not reduce the incidence of pneumonia, endotracheal re-intubation, or death after major abdominal surgery. Although CPAP has an important role in the treatment of respiratory failure after surgery, routine use of prophylactic post-operative CPAP is not recommended.FundingNational Institute for Health Research, Barts Charity, Intersurgical, Association of Anaesthetists, and Sapienza Università di Roma.