Influence of lymphopenia on long-term mortality in septic shock, a retrospective observational study.

BACKGROUND AND OBJECTIVE: The diagnosis of infection, to diagnose septic shock, has been qualified by leukocyte counts and protein biomarkers. Septic shock mortality is persistently high (20%-50%), and rising in the long term. The definition of sepsis does not include leukocyte count, and lymphopenia has been associated with its mortality in the short term. Immunosuppression and increased mortality in the long term due to sepsis have not been demonstrated. The aim is to relate the occurrence of lymphopenia and its lack of recovery during septic shock with mortality at 2 years. PATIENTS AND METHODS: Cohort of 332 elderly patients diagnosed with septic shock. Mortality at 28 days and 2 years was analysed according to leukocyte, neutrophil, and lymphocyte counts, and the ability to recover from lymphopenia (LRec). RESULTS: A total of 74.1% of patients showed lymphopenia, and 73.5% did not improve during ICU stay. Mortality was 31.0% and 50.3% at 28 days and 2 years, respectively. Lymphopenia was a predictor of early mortality (OR 2.96) and LRec of late mortality (OR 3.98). Long-term mortality was associated with LRec (HR 1.69). CONCLUSIONS: In elderly patients with septic shock, 28-day mortality is associated with lymphopenia and neutrophilia, and LRec with 2-year mortality; this may represent 2 distinct phenotypes of behaviour after septic shock.

Towards the personalization of septic shock resuscitation: the fundamentals of ANDROMEDA-SHOCK-2 trial.

Septic shock is a highly lethal and prevalent disease. Progressive circulatory dysfunction leads to tissue hypoperfusion and hypoxia, eventually evolving to multiorgan dysfunction and death. Prompt resuscitation may revert these pathogenic mechanisms, restoring oxygen delivery and organ function. High heterogeneity exists among the determinants of circulatory dysfunction in septic shock, and current algorithms provide a stepwise and standardized approach to conduct resuscitation. This review provides the pathophysiological and clinical rationale behind ANDROMEDA-SHOCK-2, an ongoing multicenter randomized controlled trial that aims to compare a personalized resuscitation strategy based on clinical phenotyping and peripheral perfusion assessment, versus standard of care, in early septic shock resuscitation.

A critical review of the perioperative fluid therapy and hemodynamic monitoring recommendations of the Enhanced Recovery of the Adult Pathway (RICA): A position statement of the fluid therapy and hemodynamic monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section (SHTF) of the Spanish Society of Anesthesiology and Critical Care (SEDAR).

In an effort to standardize perioperative management and improve postoperative outcomes of adult patients undergoing surgery, the Ministry of Health, through the Spanish Multimodal Rehabilitation Group (GERM), and the Aragonese Institute of Health Sciences, in collaboration with multiple Spanish scientific societies and based on the available evidence, published in 2021 the Spanish Intensified Adult Recovery (RICA) guideline. This document includes 12 perioperative measures related to fluid therapy and hemodynamic monitoring. Fluid administration and hemodynamic monitoring are not straightforward but are directly related to postoperative patient outcomes. The Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section (SHTF) of the Spanish Society of Anesthesiology and Critical Care (SEDAR) has reviewed these recommendations and concluded that they should be revised as they do not follow an adequate methodology.

Fluid challenges in operating room: A planned sub study of the Fluid Day observational study.

BACKGROUND: Intraoperative fluid administration is a ubiquitous intervention in surgical patients. But inadequate fluid administration may lead to poor postoperative outcomes. Fluid challenges (FCs), in or outside the so-called goal-directed fluid therapy, allows testing the cardiovascular system and the need for further fluid administration. Our primary aim was to evaluate how anesthesiologists conduct FCs in the operating room in terms of type, volume, variables used to trigger a FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC. METHODS: This was a planned substudy of an observational study conducted in 131 centres in Spain in patients undergoing surgery. RESULTS: A total of 396 patients were enrolled and analysed in the study. The median [interquartile range] amount of fluid given during a FC was 250ml (200-400). The main indication for FC was a decrease in systolic arterial pressure in 246 cases (62.2%). The second was a decrease in mean arterial pressure (54.4%). Cardiac output was used in 30 patients (7.58%), while stroke volume variation in 29 of 385 cases (7.32%). The response to the initial FC did not have an impact when prescribing further fluid administration. CONCLUSIONS: The current indication and evaluation of FC in surgical patients is highly variable. Prediction of fluid responsiveness is not routinely used, and inappropriate variables are frequently evaluated for assessing the hemodynamic response to FC, which may result in deleterious effects.

Research priorities in perioperative fluid therapy and hemodynamic monitoring: A Delphi Consensus Survey from the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section (SHTF) of the Spanish Society of Anesthesiology and Critical Care (SEDAR).

BACKGROUND: Research in fluid therapy and perioperative hemodynamic monitoring is difficult and expensive. The objectives of this study were to summarize these topics and to prioritize these topics in order of research importance. METHODS: Electronic structured Delphi questionnaire over three rounds among 30 experts in fluid therapy and hemodynamic monitoring identified through the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care. RESULTS: 77 topics were identified and ranked in order of prioritization. Topics were categorized into themes of crystalloids, colloids, hemodynamic monitoring and others. 31 topics were ranked as essential research priority. To determine whether intraoperative hemodynamic optimization algorithms based on the invasive or noninvasive Hypotension Prediction Index versus other management strategies could decrease the incidence of postoperative complications. As well as whether the use of renal stress biomarkers together with a goal-directed fluid therapy protocol could reduce hospital stay and the incidence of acute kidney injury in adult patients undergoing non-cardiac surgery, reached the highest consensus. CONCLUSIONS: The Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care will use these results to carry out the research.

Early mobilization after total hip or knee arthroplasty: a substudy of the POWER.2 study.

BACKGROUND: Early mobilization after surgery is a cornerstone of the Enhanced Recovery After Surgery (ERAS) programs in total hip arthroplasty (THA) or total knee arthroplasty (TKA). Our goal was to determine the time to mobilization after this surgery and the factors associated with early mobilization. METHODS: This was a predefined substudy of the POWER.2 study, a prospective cohort study conducted in patients undergoing THA and TKA at 131 Spanish hospitals. The primary outcome was the time until mobilization after surgery as well as determining those perioperative factors associated with early mobilization after surgery. RESULTS: A total of 6093 patients were included. The median time to achieve mobilization after the end of the surgery was 24.áhours [16.Çô30]. 4,222 (69.3%) patients moved in .ëñ 24.áhours after surgery. Local anesthesia [OR.á=.á0.80 (95% confidence interval [CI]: 0.72.Çô0.90); p.á=.á0.001], surgery performed in a self-declared ERAS center [OR = 0.57 (95% CI: 0.55.Çô0.60); p.á<.á0.001], mean adherence to ERAS items [OR.á=.á0.93 (95% CI: 0.92.Çô0.93); p.á<.á0.001], and preoperative hemoglobin [OR.á=.á0.97 (95% CI: 0.96.Çô0.98); p.á<.á0.001] were associated with shorter time to mobilization. CONCLUSIONS: Most THA and TKA patients mobilize in the first postoperative day, early time to mobilization was associated with the compliance with ERAS protocols, preoperative hemoglobin, and local anesthesia, and with the absence of a urinary catheter, surgical drains, epidural analgesia, and postoperative complications. The perioperative elements that are associated with early mobilization are mostly modifiable, so there is room for improvement.

Intraoperative crystalloid utilization variability and association with postoperative outcomes: A post hoc analysis of two multicenter prospective cohort studies.

BACKGROUND: The optimal regimen for intravenous administration of intraoperative fluids remains unclear. Our goal was to analyze intraoperative crystalloid volume administration practices and their association with postoperative outcomes. METHODS: We extracted clinical data from two multicenter observational studies including adult patients undergoing colorectal surgery and total hip (THA) and knee arthroplasty (TKA). We analyzed the distribution of intraoperative fluid administration. Regression was performed using a general linear model to determine factors predictive of fluid administration. Patient outcomes and intraoperative crystalloid utilization were summarized for each surgical cohort. Regression models were developed to evaluate associations of high or low intraoperative crystalloid with the likelihood of increased postoperative complications, mainly acute kidney injury (AKI) and hospital length of stay (LOS). RESULTS: 7580 patients were included. The average adjusted intraoperative crystalloid infusion rate across all surgeries was to 7.9 (SD 4) mL/kg/h. The regression model strongly favored the type of surgery over other patient predictors. We found that high fluid volume was associated with 40% greater odds ratio (OR 1.40; 95% confidence interval 1.01-1.95, p = 0.044) of postoperative complications in patients undergoing THA, while we found no associations for the other types of surgeries, AKI and LOS CONCLUSIONS: A wide variability was observed in intraoperative crystalloid volume administration; however, this did not affect postoperative outcomes.

Patient characteristics, clinical course and factors associated to ICU mortality in critically ill patients infected with SARS-CoV-2 in Spain: A prospective, cohort, multicentre study. / Características, evolución clínica y factores asociados a la mortalidad en UCI de los pacientes críticos infectados por SARS-CoV-2 en España: estudio prospectivo, de cohorte y multicéntrico.

BACKGROUND: The clinical course of COVID-19 critically ill patients, during their admission in the intensive care unit (UCI), including medical and infectious complications and support therapies, as well as their association with in-ICU mortality has not been fully reported. OBJECTIVE: This study aimed to describe clinical characteristics and clinical course of ICU COVID-19 patients, and to determine risk factors for ICU mortality of COVID-19 patients. METHODS: Prospective, multicentre, cohort study that enrolled critically ill COVID-19 patients admitted into 30 ICUs from Spain and Andorra. Consecutive patients from March 12th to May 26th, 2020 were enrolled if they had died or were discharged from ICU during the study period. Demographics, symptoms, vital signs, laboratory markers, supportive therapies, pharmacological treatments, medical and infectious complications were reported and compared between deceased and discharged patients. RESULTS: A total of 663 patients were included. Overall ICU mortality was 31% (203 patients). At ICU admission non-survivors were more hypoxemic [SpO2 with non-rebreather mask, 90 (IQR 83 to 93) vs. 91 (IQR 87 to 94); P<.001] and with higher sequential organ failure assessment score [SOFA, 7 (IQR 5 to 9) vs. 4 (IQR 3 to 7); P<.001]. Complications were more frequent in non-survivors: acute respiratory distress syndrome (ARDS) (95% vs. 89%; P=.009), acute kidney injury (AKI) (58% vs. 24%; P<10-16), shock (42% vs. 14%; P<10-13), and arrhythmias (24% vs. 11%; P<10-4). Respiratory super-infection, bloodstream infection and septic shock were higher in non-survivors (33% vs. 25%; P=.03, 33% vs. 23%; P=.01 and 15% vs. 3%, P=10-7), respectively. The multivariable regression model showed that age was associated with mortality, with every year increasing risk-of-death by 1% (95%CI: 1 to 10, P=.014). Each 5-point increase in APACHE II independently predicted mortality [OR: 1.508 (1.081, 2.104), P=.015]. Patients with AKI [OR: 2.468 (1.628, 3.741), P<10-4)], cardiac arrest [OR: 11.099 (3.389, 36.353), P=.0001], and septic shock [OR: 3.224 (1.486, 6.994), P=.002] had an increased risk-of-death. CONCLUSIONS: Older COVID-19 patients with higher APACHE II scores on admission, those who developed AKI grades ii or iii and/or septic shock during ICU stay had an increased risk-of-death. ICU mortality was 31%.

Patient Blood Management for primary hip and knee replacement. A survey among POWER.2 study researchers. / Patient Blood Management en artroplastia primaria de cadera y rodilla. Encuesta entre los investigadores del estudio POWER.2.

BACKGROUND: Implementation of Patient Blood Management programs remain variable in Europe, and even in centres with well-established PBM programs variability exists in transfusion practices. OBJECTIVES AND METHODS: We conducted a survey in order to assess current practice in perioperative Patient Blood Management in patients undergoing total hip and knee replacement among researchers involved in POWER.2 Study in Spain (an observational prospective study evaluating enhanced recovery pathways in orthopaedic surgery). RESULTS: A total of 322 responses were obtained (37.8%). Half of responders check Haemoglobin levels in patients at least 4 weeks before surgery; 35% treat all anaemic patients, although 99.7% consider detection and treatment of preoperative anaemia could influence the postoperative outcomes. Lack of infrastructure (76%) and lack of time (51%) are the main stated reasons not to treat anaemic patients. Iron status is routinely checked by 19% before surgery, and 36% evaluate it solely in the anaemic patient. Hb<9.9 g/dl is the threshold to delay surgery for 61% of clinicians, and 22% would consider transfusing preoperatively clinically stable patients without active bleeding. The threshold to transfuse patients without cardiovascular disease is 8 g/dl for 43%, and 7 g/dl for 34% of the responders; 75% of clinicians consider they use "restrictive thresholds", and 90% follow the single unit transfusion policy. CONCLUSIONS: The results of our survey show variability in clinical practice in Patient Blood Management in major orthopaedic surgery, despite being the surgery with the greatest tradition in these programs.

Endothelial dysfunction is an early indicator of sepsis and neutrophil degranulation of septic shock in surgical patients.

BACKGROUND: Stratification of the severity of infection is currently based on the Sequential Organ Failure Assessment (SOFA) score, which is difficult to calculate outside the ICU. Biomarkers could help to stratify the severity of infection in surgical patients. METHODS: Levels of ten biomarkers indicating endothelial dysfunction, 22 indicating emergency granulopoiesis, and six denoting neutrophil degranulation were compared in three groups of patients in the first 12 h after diagnosis at three Spanish hospitals. RESULTS: There were 100 patients with infection, 95 with sepsis and 57 with septic shock. Seven biomarkers indicating endothelial dysfunction (mid-regional proadrenomedullin (MR-ProADM), syndecan 1, thrombomodulin, angiopoietin 2, endothelial cell-specific molecule 1, vascular cell adhesion molecule 1 and E-selectin) had stronger associations with sepsis than infection alone. MR-ProADM had the highest odds ratio (OR) in multivariable analysis (OR 11·53, 95 per cent c.i. 4·15 to 32·08; P = 0·006) and the best area under the curve (AUC) for detecting sepsis (0·86, 95 per cent c.i. 0·80 to 0·91; P < 0·001). In a comparison of sepsis with septic shock, two biomarkers of neutrophil degranulation, proteinase 3 (OR 8·09, 1·34 to 48·91; P = 0·028) and lipocalin 2 (OR 6·62, 2·47 to 17·77; P = 0·002), had the strongest association with septic shock, but lipocalin 2 exhibited the highest AUC (0·81, 0·73 to 0·90; P < 0·001). CONCLUSION: MR-ProADM and lipocalin 2 could be alternatives to the SOFA score in the detection of sepsis and septic shock respectively in surgical patients with infection.

ANTECEDENTES: La estratificación de la gravedad de una infección se basa actualmente en la puntuación SOFA (Sequential Organ Failure Assessment), que es difícil de calcular fuera de la unidad de cuidados intensivos. Los biomarcadores podrían ayudar a estratificar la gravedad de la infección en pacientes quirúrgicos. MÉTODOS: Se compararon las concentraciones de 10 biomarcadores que denotan disfunción endotelial, 22 que indican granulopoyesis de emergencia y 6 que expresan la degranulación de neutrófilos en tres grupos de pacientes de tres hospitales españoles (100 con infección, 95 con sepsis y 57 con shock séptico) en las primeras doce horas después del diagnóstico. RESULTADOS: Siete biomarcadores que expresan disfunción endotelial (proadrenomedulina, sindecan-1, trombomodulina, angiopoyetina-2, endocan-1, molécula de adhesión endotelial 1 y E-selectina) mostraron una fuerte asociación con la sepsis en comparación con la infección aislada. La proadrenomedulina presentó el valor más alto de la razón de oportunidades (odds ratio, OR) en el análisis multivariable (OR 11,53, i.c. del 95% 4,15-32,08, P = 0,006) y la mejor área bajo la curva para detectar sepsis (AUC 0,86, i.c. del 95% 0,80-0,91, P < 0,001). En la comparación entre sepsis y shock séptico, los biomarcadores que mostraron la asociación más estrecha con el shock séptico fueron dos biomarcadores de degranulación de neutrófilos (proteinasa-3 y lipocalina-2) (OR 8,09, i.c. del 9% 1,34-48,91, P = 0,028; OR 6.62, i.c. del 95% 2,47-17,77, P = 0,002), pero la lipocalina-2 presentó la mejor AUC (0,81, i.c. del 95% 0,73-0,90, P < 0,001). CONCLUSIÓN: la proadrenomedulina y la lipocalina-2 podrían representar alternativas a la puntuación SOFA para detectar sepsis y shock séptico en pacientes quirúrgicos con infección.

Postoperative Outcomes Within an Enhanced Recovery after surgery protocol in gastric surgery for cancer (POWER.4): Study protocol for a prospective, multicentre, observational cohort study. / Auditoría nacional de complicaciones después de la cirugía gástrica por cáncer dentro o no de un protocolo de recuperación intensificada (POWER.4): Protocolo de un estudio prospectivo, multicéntrico, observacional de cohortes.

BACKGROUND AND OBJECTIVE: Enhanced recovery pathways or ERAS have been applied in gastric cancer surgery extrapolated from colorectal surgery. The objective of the study is to assess postoperative complications 30 days after gastric surgery for cancer, with any level of compliance with the ERAS protocol. The secondary objectives are to assess 30-day mortality, the relationship between adherence to the ERAS protocol and complications, the impact of each of the items of the protocol on postoperative complications and hospital stay, and to describe the impact of complications on length of hospital stay. MATERIALS AND METHODS: Multicenter, observational, prospective study including all consecutive patients undergoing scheduled gastric cancer surgery, over a period of 3 months, with a 30-day follow-up at participating centers, with any level of compliance with the protocol. RESULTS: The approval of the Comité Autonómico de Ética de la Investigación de Aragón has been obtained (C.P. - C.I. PI19 / 106, 27 th March 2019). POWER.4 was registered at www.clinicaltrials.gov on March 7, 2019 (NCT03865810). CONCLUSIONS: The data as a whole will be published in peer-reviewed journals. The data will not be made public by identifying each participating center. It is expected that the results of this study will identify potential areas for improvement in which more targeted research is needed.

Is mortality in elderly septic patients as high as expected? Long-term mortality in a surgical sample cohort.

PURPOSE: To determine the differences in short- and long-term mortality in elderly septic patients with multiorgan dysfunction syndrome and establish the factors related to non-survival. MATERIALS AND METHODS: A retrospective cohort study was made of 206 patients over 65 years of age with septic and septic shock criteria admitted to the ICU of Rio Hortega Hospital between January 2011 and February 2017. Study variables were obtained from electronic database records. RESULTS: A total of 206 patients were included, divided into three groups of age (65-74, 75-85, >85 years). There were no significant differences in mortality according to age group after 28 days, 90 days or one year (28.6%, 32.1% and 45.2% in the 65-74 years age group; 32.5%, 38.6% and 45.8% in the 75-85 years age group, 41%, 48.7% and 56.4% in the >85 years age group). The factors related to mortality were: chronic heart failure, non-haematological cancer, liver dysfunction and central nervous system dysfunction. CONCLUSIONS: The results indicate that there is no significant difference in mortality among the different age groups. About 50% of the elderly patients survive a septic process. There is a close relationship between the number of affected organs and days of dysfunction, the use of interventional techniques and long-term mortality.

Intensive care admission and hospital mortality in the elderly after non-cardiac surgery.

OBJECTIVE: To assess whether patient age is independently associated to Intensive Care Unit (ICU) admission after non-cardiac surgery. DESIGN: An observational cohort study of the Spanish subset of the European Surgical Outcome Study (EuSOS) was carried out. SETTING: Hospitals of the public National Health Care System and private hospitals in Spain. INTERVENTION: None. PATIENTS AND METHODS: All patients over 16 years of age undergoing inpatient non-cardiac surgery in the participating hospitals during a 7-day period in the month of April 2011 were consecutively included. MAIN VARIABLES OF INTEREST: ICU admission rate, factors associated with ICU admission and hospital mortality were assessed using logistic regression analysis and fractional polynomial regression. RESULTS: Out of 5412 patients, 677 (12.5%) were admitted to the ICU after surgery. The adjusted odds ratio (95% confidence interval [CI]) for ICU admission was 1.1 (0.8-1.4) for patients aged 65-74 years, 0.7 (0.5-1) for patients aged 75-85 years, and 0.4 (0.2-0.8) for patients over 85 years, respectively. Age, ASA score, grade of surgery (minor, intermediate, major), urgent surgery, surgical specialty, laparoscopic surgery and metastatic disease were independent factors for ICU admission. Global risk-adjusted mortality was 1.4 (95% CI 0.9-2.2). The ASA score, urgent surgery, surgical specialty and diabetes were predictors of hospital mortality. CONCLUSIONS: Elderly patients (over 80 years) appear less likely to be admitted to ICU after non-cardiac surgery in Spanish hospitals. There was no significant association between age and postoperative mortality in this cohort.

Use of failure-to-rescue to identify international variation in postoperative care in low-, middle- and high-income countries: a 7-day cohort study of elective surgery.

BACKGROUND: The incidence and impact of postoperative complications are poorly described. Failure-to-rescue, the rate of death following complications, is an important quality measure for perioperative care but has not been investigated across multiple health care systems. METHODS: We analysed data collected during the International Surgical Outcomes Study, an international 7-day cohort study of adults undergoing elective inpatient surgery. Hospitals were ranked by quintiles according to surgical procedural volume (Q1 lowest to Q5 highest). For each quintile we assessed in-hospital complications rates, mortality, and failure-to-rescue. We repeated this analysis ranking hospitals by risk-adjusted complication rates (Q1 lowest to Q5 highest). RESULTS: A total of 44 814 patients from 474 hospitals in 27 low-, middle-, and high-income countries were available for analysis. Of these, 7508 (17%) developed one or more postoperative complication, with 207 deaths in hospital (0.5%), giving an overall failure-to-rescue rate of 2.8%. When hospitals were ranked in quintiles by procedural volume, we identified a three-fold variation in mortality (Q1: 0.6% vs Q5: 0.2%) and a two-fold variation in failure-to-rescue (Q1: 3.6% vs Q5: 1.7%). Ranking hospitals in quintiles by risk-adjusted complication rate further confirmed the presence of important variations in failure-to-rescue, indicating differences between hospitals in the risk of death among patients after they develop complications. CONCLUSIONS: Comparison of failure-to-rescue rates across health care systems suggests the presence of preventable postoperative deaths. Using such metrics, developing nations could benefit from a data-driven approach to quality improvement, which has proved effective in high-income countries.

Cardiac and Pulmonary Ultrasound for Diagnosing TRALI.

Unexpected acute respiratory failure after anesthesia is a diagnostic challenge: residual neuromuscular blockade, bronchial hyperresponsiveness, laryngospasm, atelectasis, aspiration pneumonitis, and other more uncommon causes should be taken into account at diagnosis. Lung ultrasound and echocardiography are diagnostic tools that would provide the differential diagnosis. We report a suspected case of a transfusion related acute lung injury (TRALI) following administration of platelets. The usefulness of lung and cardiac ultrasound is discussed to facilitate the challenging diagnosis of the acute early postoperative respiratory failure.

Point prevalence of surgical checklist use in Europe: relationship with hospital mortality.

BACKGROUND: The prevalence of use of the World Health Organization surgical checklist is unknown. The clinical effectiveness of this intervention in improving postoperative outcomes is debated. METHODS: We undertook a retrospective analysis of data describing surgical checklist use from a 7 day cohort study of surgical outcomes in 28 European nations (European Surgical Outcomes Study, EuSOS). The analysis included hospitals recruiting >10 patients and excluding outlier hospitals above the 95th centile for mortality. Multivariate logistic regression and three-level hierarchical generalized mixed models were constructed to explore the relationship between surgical checklist use and hospital mortality. Findings are presented as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A total of 45 591 patients from 426 hospitals were included in the analysis. A surgical checklist was used in 67.5% patients, with marked variation across countries (0-99.6% of patients). Surgical checklist exposure was associated with lower crude hospital mortality (OR 0.84, CI 0.75-0.94; P=0.002). This effect remained after adjustment for baseline risk factors in a multivariate model (adjusted OR 0.81, CI 0.70-0.94; P<0.005) and strengthened after adjusting for variations within countries and hospitals in a three-level generalized mixed model (adjusted OR 0.71, CI 0.58-0.85; P<0.001). CONCLUSIONS: The use of surgical checklists varies across European nations. Reported use of a checklist was associated with lower mortality. This observation may represent a protective effect of the surgical checklist itself, or alternatively, may be an indirect indicator of the quality of perioperative care. CLINICAL TRIAL REGISTRATION: The European Surgical Outcomes Study is registered with ClinicalTrials.gov, number NCT01203605.