Editor: Deborah Sesok-Pizzini, MD, MBA, professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and chief, Division of Transfusion Medicine, Children’s Hospital of Philadelphia.
Smoking and risk of surgical bleeding: a nationwide analysis of surgical cases
November 2020—Smoking is a leading cause of death in the United States and is associated with many postoperative complications, including increased transfusion needs. Toxins in tobacco that create free radicals that damage the arterial walls and make them more susceptible to rupture and bleeding may be the link between smoking and surgical bleeding. Smoking also impairs tissue healing after surgery, most likely due to reduced oxygenation and altered function of inflammatory cells during the healing process. This may impact bleeding risk in the immediate postoperative period. The authors conducted a study in which they queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Participant Use Data File 2007–2016, which contained data from up to 680 U.S. hospitals, to test the hypothesis that smoking is associated with a higher risk of bleeding in various surgical procedures. They included in their study information about patient age, gender, surgical specialty, and smoking status. Surgical bleeding was defined as one or more RBC units transfused intraoperatively up to 72 hours postoperatively. The association between smoking and surgical bleeding was analyzed with logistic regression, which was adjusted for age, gender, body mass index, ethnicity, comorbidities, laboratory values, American Society of Anesthesiologists score, type of anesthesia, duration of surgery, work relative value unit (operative complexity), surgical specialty, and procedure year. In the 5,452,411 surgical cases included in the study, 19 percent of the patients smoked and six percent received transfusion. The analysis included surgical cases from 2007 to 2012 if data were available about smoking status, cumulative smoking in pack-years, and RBC transfusion. The odds ratios for RBC transfusion were 1.06 for smokers versus nonsmokers and 1.06 for current smokers versus those who never smoked. The odds ratios for RBC transfusion and cumulative smoking were 0.97 for greater than zero to 20 pack-years, 1.04 for greater than 20 to 40 pack-years, and 1.12 for greater than 40 pack-years. These data showed that smoking was associated with a higher risk of RBC transfusion and a proxy for surgical bleeding across all surgical specialties combined. In conclusion, the analysis showed higher risk of bleeding in smokers, demonstrated by RBC transfusion needs, across multiple surgical procedures, including general, cardiac, and vascular surgery. The authors noted that these data might motivate patients to cease smoking prior to surgery and alert surgeons and anesthesiologists about patients who may be at higher risk for bleeding in the operating room and postoperatively.
Nordestgaard AT, Rasmussen LS, Sillesen M, et al. Smoking and risk of surgical bleeding: nationwide analysis of 5,452,411 surgical cases. Transfusion. 2020;69:1689–1699.
Correspondence: Dr. Ask T. Nordestgaard at ask.tybjaerg.nordestgaard@gmail.com
Red blood cell transfusion in surgery: an observational study of U.S. trends
Red blood cell guidelines recommend restrictive RBC transfusion strategies. These transfusion guidelines for adults are based on many randomized controlled trials and systemic reviews that showed that restrictive transfusion is equal, if not superior, to liberal transfusion in many patients, including those who are undergoing cardiac or orthopedic surgery, those who are critically ill, or those who have major burns. Transfusion practices have changed over the past two decades in accordance with this evidence, and guidelines published in 2011 do not recommend RBC transfusion for nonacute, hemodynamically stable patients with hemoglobin levels above 6 to 8 g/dL. Although these recommendations have been in effect for years, data are lacking about RBC transfusion rates in most surgical subspecialties. The authors conducted a study to evaluate changes in rates of perioperative RBC transfusion over six years. The secondary objective of the study was to determine what other factors may impact rates of perioperative transfusion, including preoperative RBC transfusion, as well as prevalence of bleeding disorders and coagulopathy and proportion of minimally invasive compared to open procedures. Furthermore, the authors examined the outcomes of perioperative myocardial infarction, stroke, and all-cause mortality to determine if a restrictive RBC transfusion strategy adversely affects clinical outcomes. The study focused on 4,273,168 surgical patients for whom there were data in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database between 2011 and 2016. The authors analyzed elective and emergency cases. The perioperative period was defined as a transfusion of at least one packed RBC unit intraoperatively or up to 72 hours postoperatively. The data showed that perioperative RBC transfusion rates declined significantly from 8.4 percent in 2011 to 4.6 percent in 2017 across all surgical subspecialties. This corresponded to a significant decrease in adjusted risk for RBC transfusions (odds ratio, 0.88 in 2012 to 0.51 in 2016). Of interest, the preoperative RBC transfusion rates and the prevalence of bleeding disorders decreased over time, while minimally invasive procedures increased. A decline in perioperative RBC transfusions from 2011 to 2016 was not associated with an increase in adverse clinical outcomes. In conclusion, these data showed that the restrictive RBC guidelines favorably impacted the RBC transfusion rates over a six-year period. This was consistent across all types of surgeries, even when adjusted for variable confounders. Moreover, this decrease was not associated with an increased risk of myocardial infarction, stroke, or death from any cause. The authors noted that this was the largest sample to be used in such a study, but the dataset was impacted by the willingness of institutions to share data about their transfusion strategies. Therefore, the results may not be generalizable to all institutions.
Nordestgaard AT, Rasmussen LS, Sillesen M, et al. Red blood cell transfusion in surgery: an observational study of the trends in the USA from 2011 to 2016. Anaesthesia. 2020;75:455–463.
Correspondence: Dr. Ask T. Nordestgaard at ask.tybjaerg.nordestgaard@gmail.com