Over 1,500 abstracts were presented at the 2013 American Society of Anesthesiologists Annual Meeting in San Francisco, CA. As in previous years, a number of these abstracts examined issues directly related to patient safety. This brief review will highlight several abstracts discussed at the meeting.
Several abstracts focused on perioperative complications. Dr. Teng studied endotracheal tube cuff pressures and postoperative complications, noting that 58% of the time, the cuff pressure was outside the recommended range of 10-30 cm H2O. In addition, cuff pressures greater than 30 cm H2O were associated with increased bloody expectorant (A1113). Voscopoulos et al. evaluated a new protocol to identify patients at risk for opioid-induced respiratory depression. Using an impedance-based device, minute ventilation (MV) was measured in postoperative patients. In patients with a MV of less than 80% predicted, opioid administration may lead to potentially dangerous respiratory depression. Measuring minute ventilation in the PACU may help risk stratify patients and prevent opioid induced pulmonary morbidity (A3041). Pulmonary complications were also evaluated by Schumann et al.; specifically patients undergoing bariatric surgery were retrospectively analyzed. Those patients with metabolic syndrome (obesity, hyperlipidemia, hypertension, impaired glucose tolerance) were found to be at increased risk of multiple pulmonary complications (pneumonia, atelectasis, ARDS, pleural effusion, respiratory failure) (BOC05). The incidence and duration of postoperative hypoxemia was prospectively studied by Shahinyan. Analysis of 159 patients revealed that hypoxemia was surprisingly common among elective surgical patients with 15% of patients having a saturation of less than 85% for more than one hour (BOC12).
Cardiovascular events remain a major source of morbidity in the postanesthetic care unit (PACU). A retrospective analysis of 107,671 patients was performed by Bondoc et al. as part of a quality assurance database. The overall PACU complication rate was 14.8% with postoperative nausea and vomiting as the most common complication (5.5%) and cardiovascular complications as the second most common (2.5%) (A3034).Several abstracts focused on an association between hypothermia and perioperative morbidity. Sun et al. evaluated a perioperative database registry of 51,274 non-cardiac surgical patients to assess the effect of intraoperative hypothermia on hospital length of stay. Hypothermia less than 34.5 °C was independently associated with increase length of stay (A1272); and 5% of patients were noted to have a core temperature less than 35 °C for more than 1 hour (A1267).
Pimental performed an analysis to better delineate local risk for perioperative ocular injury at Brigham and Women’s Hospital. In this population, eye injury was rare and associated only with general anesthesia and cases longer than 90 minutes (A4107). Choi and colleagues randomized 66 patients to receive balanced anesthesia or total intravenous anesthesia (TIVA) with propofol. The authors evaluated intraocular pressure (IOP) in patients undergoing robotic radical prostatectomy. Increases in IOP were prevented by the use of TIVA despite steep Trendelenburg and pneumoperitoneum (A5007).
Consistent with prior literature, abstracts from the ASA suggest that perioperative transfusion is associated with significant morbidity. Basora and colleagues prospectively studied 1331 patients presenting for knee arthroplasty. Transfusion of blood was found to be an independent predictor of deep prosthetic joint infection (odds ratio 4.5) (A2268). In a study by Frank et al., patients refusing blood transfusions were compared with those accepting allogeneic blood transfusions. Although mortality and morbidity were similar between cohorts, those refusing transfusion were observed to have a lower infection rate (A2190). In a separate retrospective analysis of patients with non-small cell lung cancer, Cata et al. found a reduced overall survival among patient receiving blood transfusions (A2227). While there are limitations to the presented data , the findings are consistent with a growing body of literature supporting an increase in morbidity and mortality with blood transfusion.
In addition, several abstracts evaluated risk factors that may increase the rate of transfusion. Panjasawatwong et al. studied the effect of hypothermia on red blood cell transfusion in 51,274 patients. Hypothermia was significantly associated with blood transfusion in an incremental fashion, suggesting that the maintenance of normothermia may reduce the need for blood transfusion and the concomitant risks (A2230). Following recommendations from the Society of Cardiovascular Anesthesiologists and Society of Thoracic Surgeons, Brooker et al. evaluated the implementation of a multimodal blood conservation strategy in a community hospital setting. The institution of this strategy decreased transfusion rates in cardiac surgical patients. PRBC transfusion decreased from 1.7 units/patient/year to 0.33 units/patient/year (p<0.04) (A2194).
Safety and Communication
Iatrogenic harm is a major threat to patient safety and the investigation of methods of attenuating this risk was again an important topic at the 2013 ASA. Nosocomial infection can result from poor hand hygiene and several abstracts focused on this issue. Parks and colleagues from the University of Wisconsin collected behavioral and hygiene data as part of a quality improvement database. The study noted that compliance with hand hygiene by members of an acute pain service improved significantly when personal sanitizing gel dispensing devices were worn compared to communal devices on the wall (A2309). It is clearly important to improve hand hygiene in an attempt to decrease hospital-acquired infections. On the other “hand,” Cole and colleagues discovered the potential for bacterial contamination of the hand sanitizer devices. Dispensers were sampled with and without routine cleaning of the dispenser. Cleaning of the dispenser in between surgical cases may reduce pathogen load and should be considered as part of a routine room turnover protocol (A2307).
Communication also plays a major role in medical error and patient safety. Handoff communication among anesthesia personnel was a major topic in the 2013 abstracts. Investigators from Wayne State University studied intraoperative communication between anesthesia providers. Only 7.4% of responders stated that “they have never had a complication” due to poor handover communication (A4210). McLaren instituted a standardized handoff at the University of Kansas and found improved thoroughness and delivery of handoffs without prolonging the time spent in handoff communication (A4304). A similar study by Mason and colleagues scored patient information transfer in groups with and without a standardized handoff among obstetric anesthesia providers. Standardizing the handoff significantly improved information transfer scores (A5009). Dr. Agarwala and colleagues instituted a checklist to aid patient information transfer. Utilization of this checklist for patient handoffs improved both the transfer of information and retention by anesthesia care providers (BOC03).
Neuromuscular Blockade: Too Much or Too Little
Residual neuromuscular block in the postoperative period is an important patient safety issue. Galarneau and colleagues found that a lower train-of-four at extubation resulted in a higher incidence of complications and health care resource utilization perioperatively including increased nurse-patient interventions and increased nurse staffing (A1053). As awareness of residual neuromuscular block and its risk has increased, the issue of inadequate block for good surgical conditions has been raised (A1054, A1055, A1052). From the surgical perspective, there are potential problems associated with inadequate depth of muscle relaxation such as poor closure that could lead to incisional hernia. Finally, Todd et al. described the successful implementation of quantitative monitoring in an academic setting along with a potential reduction in “relaxant-related reintubation” (A5010).
This brief review summarized only a small number of abstracts on patient safety presented at the 2013 Annual Meeting. This is not an endorsement of the methods, results, or conclusions of any particular abstract. To view other abstracts on patient safety, or to obtain further information on the abstracts discussed in this review, please visit the Anesthesiology website at www.anesthesiology.org.
Dr. Shear is the Director of Anesthesia Simulation NorthShore University HealthSystem and Clinical Assistant Professor, Department of Anesthesia/Critical Care at the University of Chicago.
Dr. Greenberg is Director of Critical Care Services, Evanston Hospital; Co-Director for Resident Education at the Department of Anesthesia, NorthShore University HealthSystem; Clinical Assistant Professor, Department of Anesthesiology Critical Care, University of Chicago; and a member of the APSF Editorial Board.
Dr. Murphy is Director of Cardiac Anesthesia, NorthShore University HealthSystem; Clinical Professor, Department of Anesthesia/Critical Care at the University of Chicago; and a member of the APSF Editorial Board.