Risk Factors for Postoperative Pulmonary Complications
Smoking: 1.4-4.3x increased risk of complications
Risk does not decrease until 8 wks after smoking cessation
COPD: 2.7 -4.7x increased risk of complications
ASA Class >2:
Age >70 y/o: although age > 70 has been statistically identified as a risk factor, pulmonary complications are more strongly related to coexisting conditions than to chronologic age, and therefore advanced age alone is not a reason to withhold surgery
With the Exception of Increased Risk for Acute Pulmonary Embolism, There is No Evidence that High BMI is a Major Risk Factor for Postoperative Complications in Otherwise Healthy Obese Patients Undergoing Noncardiac Surgery
None of the Published and Widely Used Cardiac Risk Indices for Noncardiac Surgery Include Obesity as a Risk Factor for Postoperative Cardiac Complications
Study of Body Mass Index as a Correlate of Postoperative Complications and Resource Utilization (Am J Med, 1997) [MEDLINE]
Overall, BMI was Not Significantly Correlated with Postoperative Complications or Length of Stay
However, Overweight Patients Who Underwent Abdominal or Gynecologic Procedures Had Higher Wound Infection Rates
Patients with the Highest and Lowest BMIs Had Significantly Higher Adjusted Total Costs
Obesity is a Risk Factor for Postoperative Pulmonary Embolism (NEJM, 1999) [MEDLINE] (Lancet, 2003) [MEDLINE] (Ann Intern Med, 2006) [MEDLINE]
Postoperative Atelectasis May Persist for >24 hrs in Severely Obesity, in Contrast to Non-Obesity, Where Complete Resorption of Atelectasis is Observed in That Same Period of Time (Anesth Analg, 2002) [MEDLINE]
Study of Obesity as a Risk Factor for Postoperative Complications (Lancet, 2003) [MEDLINE]
Obesity Alone was Not a Risk Factor for Postoperative Complications
Matched Case Control Study of Patients Undergoing Noncardiac Surgery (Obes Surg, 2004) [MEDLINE]: n = 1,962
Obesity was Not Associated with Increased Mortality Rate (1.1% in Obese Patients vs 1.2% in Controls)
Study of the Prevalence of Obesity and Postoperative Complications in a Veterans Affairs Medical Center General Surgery Population (Am Surg, 2007) [MEDLINE]
Postoperative Complications Developed in 5.5 % of All Surgical Patients
23.3% were Obese and 76.7 % were Nonobese
There was No Statistically Significant Difference Between the Obese and Nonobese Groups (P = 0.54).
Study of Obesity as a Risk Factor for Unanticipated Admission After Ambulatory Surgery (Mayo Clin Proc, 2008) [MEDLINE]
Obesity was Not a Significant Independent Risk Factor for Unplanned Admission After Ambulatory Surgery
Large, Multi-Institutional Prospective Cohort Study of Patients Undergoing Non-Bariatric General Surgery (Ann Surg, 2009) [MEDLINE]: n = 118,707
Obesity was Inversely Associated with the Postoperative Mortality Rate (Odds Ratio 0.85; 95% CI: 0.75-0.99)
This Has Been Called the “Obesity Paradox”
Possible Explanations
Obesity Involves a Low-Grade, Chronic Inflammatory State Which May Be Primed to Mount an Appropriate Inflammatory and Immune Response to the Stress of Surgery
Obesity Provides Additional Nutritional Reserve
Postpneumonectomy Complications are Higher in Obese Patients (Eur J Cardiothorac Surg, 2011) [MEDLINE] (see Lung Resection)
Study of the Effect of Body Mass Index on Perioperative Outcomes After Major Surgery Using Data from the National Surgical Quality Improvement Program (ACS-NSQIP) 2005-2011 (World J Surg, 2015) [MEDLINE]
Nearly, 74 % of Patients had a BMI Disturbance
Majority Being Overweight (35.3 %) or Obese (29.8 %)
Morbidly obese patients constituted a small but significant proportion of the patients (5.7 %; n = 8067)
In adjusted-analyses, morbidly obese patients had significantly increased odds of wound complications in 15 of the examined procedures, of renal complications after 6-procedures, of thromboembolism after 5-procedures, of pulmonary, septic and UTI complications after 2-procedures, and of cardiovascular complications after CABG
Conversely, Obese/Overweight Patients, Except for increased odds of wound complications after select procedures, had significantly decreased odds of perioperative mortality, prolonged Length of Stay and blood transfusion relative to normal BMI patients after 4, 8, and 9 of the examined procedures
Conclusions
The effect of BMI on outcomes is procedure specific
Patients with BMI between 18.5 and 40-kg/m(2) at time of surgery fare equally well with regard to complications and mortality
However, Morbidly Obese Patients are at Risk for Postoperative Complications and Targeted Preoperative Optimization May Improve Outcomes and Attenuate a Disparity in Access to Care
Study of Effect of Obesity on Postoperative Infectious Complications in Free Tissue Transfer for Head and Neck Reconstructive Surgery (JAMA Otolaryngol Head Neck Surg, 2017) [MEDLINE]: n = 415
Risk Factors for Infectious Complications
Type 2 Diabetes Mellitus
Use of an Alternative Antibiotic Regimen
High BMI (Reflective of Obesity was Not Found to Be Statistically Significant as an Independent Risk Factor for Postoperative Infectious Complications (Odds Ratio 1.19; 95% CI: 0.48-2.92)
Epidemiology in Cardiac Surgery
In Cardiac Surgery, Some Studies Have Demonstrated a Higher Rate of Postoperative Complications for Patients with Obesity
Increased Hospital Length of Stay (Heart Lung Circ, 2007) [MEDLINE]
Body mass index as a correlate of postoperative complications and resource utilization. Am J Med. 1997;102(3):277 [MEDLINE]
Preoperative pulmonary evaluation. N Engl J Med. 1999;340(12):937 [MEDLINE]
Risk of morbidity and in-hospital mortality in obese patients undergoing coronary artery bypass surgery. Eur J Cardiothorac Surg. 2002;22(5):787 [MEDLINE]
Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem. Anesth Analg 2002 12;95(6):1788–92, table of contents [MEDLINE]
Obesity in general elective surgery. Lancet. 2003;361(9374):2032 [MEDLINE]
Increased body mass index and peri-operative risk in patients undergoing non-cardiac surgery. Obes Surg. 2004;14(2):275 [MEDLINE]
Obesity and risk of new-onset atrial fibrillation after cardiac surgery. Circulation. 2005;112(21):3247 [MEDLINE]
Preoperative pulmonary risk stratification for noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med. 2006;144(8):581 [MEDLINE]
The prevalence of obesity and postoperative complications in a Veterans Affairs Medical Center general surgery population. Am Surg. 2007;73(10):1009 [MEDLINE]
Effect of obesity on early morbidity and mortality following cardiac surgery. Heart Lung Circ. 2007;16(1):31 [MEDLINE]
Obesity as a risk factor for unanticipated admissions after ambulatory surgery. Mayo Clin Proc. 2008;83(8):908 [MEDLINE]
The obesity paradox: body mass index and outcomes in patients undergoing nonbariatric general surgery. Ann Surg. 2009;250(1):166 [MEDLINE]
The Effect of Body Mass Index on Perioperative Outcomes After Major Surgery: Results from the National Surgical Quality Improvement Program (ACS-NSQIP) 2005-2011. World J Surg. 2015 Oct;39(10):2376-85 [MEDLINE]
Association of Body Mass Index With Infectious Complications in Free Tissue Transfer for Head and Neck Reconstructive Surgery. JAMA Otolaryngol Head Neck Surg. 2017;143(6):574 [MEDLINE]
Postoperative complications in patients with obstructive sleep apnea. Chest. 2012;141(2):436 [MEDLINE]
Practice guidelines for the perioperative management of patients with obstructive sleep apnea: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Management of patients with obstructive sleep apnea. Anesthesiology. 2014 Feb;120(2):268-86 [MEDLINE]
