Intraoperative management and pressure ulcers: not where the problem lies?

www.ccmjournal. org 199 Although anesthesiologists have long had the experience of being blamed for patient outcomes after surgery, it was not until the 1990s that anesthesiologists could adapt their practice based on randomized controlled trials of postoperative outcomes. In this issue of Critical Care Medicine, O’Brien et al (1) move this discipline forward by employing an electronic anesthesia record to explore how intraoperative management affects the postoperative development of pressure ulcers in patients admitted to the ICU for at least 48 hours. Slogoff and Keats (2), in 1985, demonstrated that higher heart rates were associated with myocardial ischemia. In the 1990s and 2000s, a flood of randomized controlled trials demonstrated that anesthesiologists could intervene to prevent complications and improve outcomes after surgery. Maintenance of normothermia was demonstrated to reduce surgical site infection in colon surgery patients (3), to reduce blood loss and transfusion in hip surgery patients (4), to accelerate metabolism of neuromuscular blocking agents (5), and to reduce adverse myocardial outcomes in patients undergoing major vascular surgery (6). Preventing tachycardia or maintaining heart rate in the low range of normal was shown to reduce adverse myocardial outcomes in high-risk patients, whether by administration of beta blockers (7) or clonidine (8). Administration of antiemetic agents intraoperatively was shown to reduce postoperative nausea and vomiting (9), and some anesthetic agents were shown to have intrinsic antiemetic properties. Intraoperative management has long been blamed for pressure ulcers that develop postoperatively. Patients are immobile under anesthesia and there is the possibility of prolonged pressure over a bony prominence given surgical positioning requirements. Great efforts are made to prevent pressure intraoperatively when positioning patients, yet pressure ulcers continue to develop, especially in postoperative patients who require critical care. Hospital-acquired pressure ulcers (stage 3 and 4) are now nonreimbursable and considered “reasonably preventable” through compliance with evidence-based guidelines (“never events”). Efforts to identify targets for prevention have thus become increasingly important. What does the current study add? The accurate and detailed information on intraoperative management offered by centricity, the intraoperative electronic anesthesia record probed for the current study, allowed the authors to investigate in detail intraoperative factors that affect whether a pressure ulcer develops in a patient in the ICU. What is particularly notable in their results is how little impact intraoperative management appeared to have. As in previous studies (10), the authors identified numerous patient factors that predicted higher risk of pressure ulcers; of these, existing airway, underweight body mass index, noncardiac surgery, congestive heart failure, renal failure, age, and American Society of Anesthesiologists Risk Classification 4 or 5 were independent predictors. The skin is the largest organ in the body. That pressure ulcers are a marker of illness and a prognostic indicator is not surprising. To determine intraoperative management factors associated with pressure ulcers, the authors created a matched dataset of patients with and without pressure ulcers that controlled for patient preoperative characteristics and comorbidities. The resulting dataset was fairly small (244 patients total; 122 out of 288 patients with stage II, III, and IV, deep tissue injury, or unstageable pressure ulcers were included). The only intraoperative management factor that reached statistical significance as a risk factor was administration of blood products. Further research is warranted to clarify if the need for transfusion is a marker of severity of illness or of more extensive surgery and associated greater blood loss and therefore greater likelihood of reduced skin perfusion, or is related to adverse effects of blood transfusion itself. Median case length was about 60 minutes longer in patients in whom pressure ulcers developed, but there was a high degree of variability in case length and this was not significant (p = 0.07). The current study did not evaluate intraoperative hypothermia, which is a known risk factor (11). Hypothermia is Copyright © 2013 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins DOI: 10.1097/CCM.0b013e31829ec875 Harriet W. Hopf, MD, FUHM Department of Anesthesiology University of Utah School of Medicine Salt Lake City, UT