Jaume Canet

Prediction of Postoperative Pulmonary Complications in a Population-based Surgical Cohort

Background:Current knowledge of the risk for postoperative pulmonary complications (PPCs) rests on studies that narrowly selected patients and procedures. Hypothesizing that PPC occurrence could be predicted from a reduced set of perioperative variables, we aimed to develop a predictive index for a broad surgical population. Methods:Patients undergoing surgical procedures given general, neuraxial, or regional anesthesia in 59 hospitals were randomly selected for this prospective, multicenter study. The main outcome was the development of at least one of the following: respiratory infection, respiratory failure, bronchospasm, atelectasis, pleural effusion, pneumothorax, or aspiration pneumonitis. The cohort was randomly divided into a development subsample to construct a logistic regression model and a validation subsample. A PPC predictive index was constructed. Results:Of 2,464 patients studied, 252 events were observed in 123 (5%). Thirty-day mortality was higher in patients with a PPC (19.5%; 95% [CI], 12.5–26.5%) than in those without a PPC (0.5%; 95% CI, 0.2–0.8%). Regression modeling identified seven independent risk factors: low preoperative arterial oxygen saturation, acute respiratory infection during the previous month, age, preoperative anemia, upper abdominal or intrathoracic surgery, surgical duration of at least 2 h, and emergency surgery. The area under the receiver operating characteristic curve was 90% (95% CI, 85–94%) for the development subsample and 88% (95% CI, 84–93%) for the validation subsample. Conclusion:The risk index based on seven objective, easily assessed factors has excellent discriminative ability. The index can be used to assess individual risk of PPC and focus further research on measures to improve patient care.

Protective versus Conventional Ventilation for Surgery: A Systematic Review and Individual Patient Data Meta-analysis.

Background:Recent studies show that intraoperative mechanical ventilation using low tidal volumes (VT) can prevent postoperative pulmonary complications (PPCs). The aim of this individual patient data meta-analysis is to evaluate the individual associations between VT size and positive end–expiratory pressure (PEEP) level and occurrence of PPC. Methods:Randomized controlled trials comparing protective ventilation (low VT with or without high levels of PEEP) and conventional ventilation (high VT with low PEEP) in patients undergoing general surgery. The primary outcome was development of PPC. Predefined prognostic factors were tested using multivariate logistic regression. Results:Fifteen randomized controlled trials were included (2,127 patients). There were 97 cases of PPC in 1,118 patients (8.7%) assigned to protective ventilation and 148 cases in 1,009 patients (14.7%) assigned to conventional ventilation (adjusted relative risk, 0.64; 95% CI, 0.46 to 0.88; P < 0.01). There were 85 cases of PPC in 957 patients (8.9%) assigned to ventilation with low VT and high PEEP levels and 63 cases in 525 patients (12%) assigned to ventilation with low VT and low PEEP levels (adjusted relative risk, 0.93; 95% CI, 0.64 to 1.37; P = 0.72). A dose–response relationship was found between the appearance of PPC and VT size (R2 = 0.39) but not between the appearance of PPC and PEEP level (R2 = 0.08). Conclusions:These data support the beneficial effects of ventilation with use of low VT in patients undergoing surgery. Further trials are necessary to define the role of intraoperative higher PEEP to prevent PPC during nonopen abdominal surgery.

Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers.

Postoperative pulmonary complications are associated with increased morbidity, length of hospital stay, and mortality after major surgery. Intraoperative lung-protective mechanical ventilation has the potential to reduce the incidence of postoperative pulmonary complications. This review discusses the relevant literature on definition and methods to predict the occurrence of postoperative pulmonary complication, the pathophysiology of ventilator-induced lung injury with emphasis on the noninjured lung, and protective ventilation strategies, including the respective roles of tidal volumes, positive end-expiratory pressure, and recruitment maneuvers. The authors propose an algorithm for protective intraoperative mechanical ventilation based on evidence from recent randomized controlled trials.

Predicting postoperative pulmonary complications: implications for outcomes and costs.

Purpose of review This review of progress toward reliable prediction of postoperative pulmonary complications (PPCs) discusses risk assessment against the background of patient management strategies, clinical outcomes, and cost of healthcare. Recent findings Among the variety of conditions grouped as PPCs are pneumonia, aspiration pneumonitis, respiratory failure, reintubation within 48 h, weaning failure, pleural effusion, atelectasis, bronchospasm, and pneumothorax. PPC incidence rates range from 2 to 40% depending on context. These events increase mortality, postoperative length of stay, ICU admissions, hospital readmissions, and costs. PPC-associated mortality varies, but can reach as high as 48% in some contexts. ICU admission rates are between 9.5 and 91% higher in patients with PPCs. The mean increase in PPC-related postoperative length of stay is approximately 8 days. The cost of surgery can be two-fold to 12-fold higher when PPCs develop. Strategies proposed to reduce the impact of modifiable risk factors include alcohol and smoking abstinence before surgery, shortening the duration of surgery, and physiotherapy and incentive spirometry techniques; however, little scientific evidence supports them at this time. Summary PPCs are associated with a higher incidence of life-threatening events and higher costs. Reliable PPC risk-stratification tools are essential for guiding clinical decision-making in the perioperative period. The care team can act on modifiable factors and optimize vigilance over nonmodifiable ones. It would be useful to focus resources on determining whether low-cost preemptive interventions improve outcomes satisfactorily or new strategies need to be developed.

Predicting postoperative pulmonary complications in the general population.

Purpose of review Postoperative pulmonary complications (PPCs) are common and lead to longer hospital stays and higher mortality. A wide range of patient, anaesthetic and surgical factors have been associated with risk for PPCs. This review discusses our present understanding of PPC risk factors that can be used to plan preoperative risk reduction strategies. The methodological and statistical basis for building risk scores is also described. Recent findings Studies in specific surgical populations or large patient samples have identified a range of predictors of PPC risk. Factors such as age, types of comorbidity and surgical characteristics have been found to be relevant in most of these studies. Recently, researchers have begun to develop risk scoring systems for a PPC composite outcome or for specific PPCs, especially pneumonia and respiratory failure. Preoperative arterial oxyhaemoglobin saturation is an objective measure that is easy to record and discriminates level of risk for impaired cardiorespiratory function. Preoperative anaemia and recent respiratory infection are factors that have lately been found to confer risk for PPCs. Summary PPC risk prediction scales based on large population studies are being developed. New studies to confirm the validity of these scales in different geographic areas will be needed before we can be sure of their generalizability.

Genetic and Clinical Factors Associated with Chronic Postsurgical Pain after Hernia Repair, Hysterectomy, and Thoracotomy: A Two-year Multicenter Cohort Study.

Background: Chronic postsurgical pain (CPSP) has been linked to many surgical settings. The authors aimed to analyze functional genetic polymorphisms and clinical factors that might identify CPSP risk after inguinal hernia repair, hysterectomy, and thoracotomy. Methods: This prospective multicenter cohort study enrolled 2,929 patients scheduled for inguinal hernia repair, hysterectomy (vaginal or abdominal), or thoracotomy. The main outcome was the incidence of CPSP confirmed by physical examination 4 months after surgery. The secondary outcome was CPSP incidences at 12 and 24 months. The authors also tested the associations between CPSP and 90 genetic markers plus a series of clinical factors and built a CPSP risk model. Results: Within a median of 4.4 months, CPSP had developed in 527 patients (18.0%), in 13.6% after hernia repair, 11.8% after vaginal hysterectomy, 25.1% after abdominal hysterectomy, and 37.6% after thoracotomy. CPSP persisted after a median of 14.6 months and 26.3 months in 6.2% and 4.1%, respectively, after hernia repair, 4.1% and 2.2% after vaginal hysterectomy, 9.9% and 6.7% after abdominal hysterectomy, and 19.1% and 13.2% after thoracotomy. No significant genetic differences between cases and controls were identified. The risk model included six clinical predictors: (1) surgical procedure, (2) age, (3) physical health (Short Form Health Survey-12), (4) mental health (Short Form Health Survey-12), (5) preoperative pain in the surgical field, and (6) preoperative pain in another area. Discrimination was moderate (c-statistic, 0.731; 95% CI, 0.705 to 0.755). Conclusions: Until unequivocal genetic predictors of CPSP are understood, the authors encourage systematic use of clinical factors for predicting and managing CPSP risk.

Evaluación y manejo de la vía aérea difícil prevista y no prevista: Adopción de guías de práctica

Los algoritmos de manejo de la via aerea dificil (VAD) comprenden un conjunto de estrategias organizadas para facilitar la eleccion de las tecnicas de ventilacion e intubacion con mas probabilidad de exito y menor riesgo de lesion de la via aerea. Las recomendaciones estan basadas en la revision exhaustiva y sistematica de la evidencia disponible y en la opinion de los expertos. La meta es garantizar la oxigenacion del paciente en una situacion de potencial riesgo vital, rapidamente cambiante, que exige una toma de decisiones agil. Su objetivo principal es disminuir el numero y la gravedad de los incidentes criticos asi como las complicaciones que se pueden producir durante el abordaje de la via aerea. Los objetivos secundarios son promover una evaluacion adecuada de la via aerea y el aprendizaje y entrenamiento de las diferentes tecnicas de control de la via aerea. Desde hace unos anos, diversas sociedades nacionales de Anestesiologia (Americana, Francesa, Canadiense, Alemana, Italiana) han editado sus algoritmos de manejo de la via aerea. Tambien se han creado sociedades internacionales especificas para promocionar la practica segura del manejo de la via aerea mediante la investigacion y la educacion, como la SAM (Society for Airway Management, www.sam.zorebo.com), la DAS (Difficult Airway Society, www.das.uk.com) y la EAMS (European Airway Management Society, www.eams.eu.com). De estas, la ASA (American Society of Anesthesiology) y la DAS han publicado recientemente sus algoritmos y muchas instituciones y Servicios de Anestesiologia han hecho sus propias versiones. Esta diversificacion responde a la necesidad de adaptar las estrategias recomendadas a los recursos humanos y materiales de cada entorno, los conocimientos y experiencia personales asi como a las caracteristicas de los pacientes. Aunque no hay estudios que comparen la efectividad de los diferentes algoritmos, los expertos coinciden en que su uso y una correcta planificacion mejoran los resultados del manejo de la via aerea. Sin embargo, la influencia de las guias sobre la practica clinica es dificil de definir, compleja de analizar y variable en el tiempo. Un diseno esmerado, unido a campanas de difusion periodicas, facilitaria su aprendizaje y retencion pudiendo mejorar su efectividad. Algunos algoritmos tienen estructura de arbol e incluye multiples opciones para cada situacion. Este es el caso del algoritmo de la ASA, en los que el listado de tecnicas y dispositivos opcionales aparece en un anexo. Esta disposicion no es facil de recordar, como se refleja en varios estudios realizados tanto entre residentes como especialistas. Por otro lado, el algoritmo de la DAS tiene un diseno de diagrama de flujo con planes secuenciales y un numero limitado de opciones y tecnicas en cada punto. Comprende tres diagramas de control de la VAD no prevista para las situaciones de anestesia electiva, induccion de secuencia rapida y situacion de ventilacion e intubacion imposible, pero no contempla la VAD prevista. El algoritmo de manejo de la VAD que presentamos se proyecto con la intencion de abarcar la valoracion preoperatoria de la via aerea, el desarrollo de diferentes esquemas de control de la VAD, en situaciones que requieren abordajes especificos (situacion de reanimacion y emergencias, ventilacion unipulmonar, pediatria y obstetricia) y el abordaje de la extubacion de este tipo de pacientes. Hasta hoy se han desarrollado los esquemas de actuacion para la evaluacion preoperatoria de la via aerea y el manejo de la situacion de VAD prevista y no prevista. El objetivo de este trabajo es difundir el algoritmo de evaluacion y manejo de la via aerea dificil adoptado por la Societat Catalana d’Anestesiologia, Reanimacio i Terapeutica del Dolor (SCARTD).

Postoperative respiratory failure: pathogenesis, prediction, and prevention.

Purpose of reviewThis review discusses our present understanding of postoperative respiratory failure (PRF) pathogenesis, risk factors, and perioperative-risk reduction strategies. Recent findingsPRF, the most frequent postoperative pulmonary complication, is defined by impaired blood gas exchange appearing after surgery. PRF leads to longer hospital stays and higher mortality. The time frame for recognizing when respiratory failure is related to the surgical-anesthetic insult remains imprecise, however, and researchers have used different clinical events instead of blood gas measures to define the outcome. Still, studies in specific surgical populations or large patient samples have identified a range of predictors of PRF risk: type of surgery and comorbidity, mechanical ventilation, and multiple hits to the lung have been found to be relevant in most of these studies. Recently, risk-scoring systems for PRF have been developed and are being applied in new controlled trials of PRF-risk reduction measures. Current evidence favors carefully managing intraoperative ventilator use and fluids, reducing surgical aggression, and preventing wound infection and pain. SummaryPRF is a life-threatening event that is challenging for the surgical team. Risk prediction scales based on large population studies are being developed and validated. We need high-quality trials of preventive measures, particularly those related to ventilator use in both high risk and general populations.

Antecedentes, objetivos y método de la encuesta de actividad anestésica en Cataluña (ANESCAT 2003)

Fundamento y objetivo En todo el mundo el incremento de la actividad anestesica y la falta de anestesiologos suscitan preocupacion. En 2003 la Societat Catalana d’Anestesiologia, Reanimacio i Terapeutica del Dolor llevo a cabo un estudio para cuantificar la actividad anestesiologica en Cataluna (Espana) (ANESCAT 2003). Pacientes y metodo ANESCAT es un conjunto de 3 encuestas para cuantificar la actividad anestesiologica y los recursos. Se estimo que la muestra necesaria para la representacion de las anestesias anuales en Cataluna era de 12.228 casos. Se llevo a cabo un estudio prospective transversal en forma de encuesta realizada en 14 dias aleatorios del ano 2003. Cada centro designo un coordinador responsible de que se cumplimentara un cuestionario para cada anestesia, el cual recogia informacion de las caracteristicas del paciente, tecnica anestesica y procedimiento para el que se realizaba. Resultados En ANESCAT participaron 131 centros sanitarios publicos y privados, el 100% de los que practicaron anestesias en el ano 2003. La distribucion geografica de estos fue: Barcelona ciudad, 54 (41,2%); resto de la provincia, 39 (29,8%); Tarragona, 15 (11,5%);Girona, 14 (10,7%), y Lleida 9, (6,9%). Se recogieron 23.136 cuestionarios de anestesias; la variacion del numero de cuestionarios recogidos los dias laborables de corte fue de un 1,85% y el porcentaje de datos incompletos fue inferior al 5%. Ademas, se recibieron 765 cuestionarios unipersonales de actividad individualizada. Conclusiones Con una organizacion y metodo sencillos, y una elevada motivacion de un colectivo de anestesiologos, fue posible conducir un estudio extenso que permitio conocer con una gran precision la actividad que realiza dentro de un territorio. Este tipo de estudios es necesario para introducir cambios en la organizacion y los requerimientos de recursos.

Lightwand Tracheal Intubation with and without Muscle Relaxation

Background:Lightwand tracheal intubation is a suitable technique for patients who are difficult to intubate but who are receiving effective ventilation. The effect of muscle relaxants on the efficacy of lightwand intubation has not yet been evaluated. The authors conducted a prospective, double-blind, placebo-controlled study to assess the effectiveness and incidence of complications of lightwand tracheal intubation performed during general anesthesia with and without the use of a muscle relaxant in patients with apparently normal airway anatomy. Methods:One hundred seventy-six patients who required orotracheal intubation were prospectively included. Anesthesia was administered using propofol (2 mg/kg, then 3 mg · kg−1 · h−1) and remifentanil (1 &mgr;g/kg, then 0.3 &mgr;g · kg−1 · min−1). Patients were randomly assigned to one of two groups (n = 88 for each) to receive rocuronium 0.6 mg/kg or saline intravenously. Lightwand orotracheal intubation (Trachlight®; Laerdal Medical Inc., Armonk, NY) was attempted after 3 min. The authors recorded the number of successful intubations, the number of attempts and their duration, and events during the procedure. Results:The failure rate of lightwand intubation was 12% in the placebo group and 2% in the rocuronium group (P = 0.021). Patients in the placebo group received more multiple intubation attempts (P < 0.001), required a greater intubation time (77 ± 65 vs. 52 ± 31 s; P = 0.002) and experienced a greater incidence of events during intubation (61 vs. 0%; P < 0.001) than patients in the rocuronium group. Conclusions:The use of muscle relaxants in patients with apparently normal airways is associated with a lower failure rate, decreased intubation time, and fewer attempts when performing lightwand orotracheal intubation.