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October 16-20, 2010 San Diego, CA Home Abstract Archive Search Abstracts 2010 Session Grid 2010 Meeting Website Policy Statements ASA Website Feedback 
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A985
October 20, 2008 9:00 AM - 11:00 AM Room Hall E2-Area D, |
| The Impact of Anesthesia Awareness Risk Reduction Strategies: A Literature Review |
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Ammar Y. Divan, M.D., Donald M. Mathews, M.D. Anesthesiology, St Vincent Catholic Medical Center-St Vincent's Manhattan, New York, New York |
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Introduction: The incidence of recall of intraoperative events following general anesthesia (anesthesia awareness, AA) is one of the more controversial issues in anesthesia practice today. The incidence of AA in published studies ranges from 0 to 2.3%. Recent studies have aimed to risk stratify patients for AA and assess the value of various risk reduction strategies in lowering incidence. This literature review was undertaken to estimate the incidence of AA in current practice and to determine if AA risk reduction strategies have benefit. Methods: PubMed and Embase were searched for papers including “anesthesia [or anaesthesia]” or “intraoperative” and “recall” or “awareness”. Baseline risk for awareness was determined to be low, average or high based on the population studied. Studies that employed an AA risk-reduction strategy (RRS: anesthesia delivery protocol or processed-electroencephalographic (EEG) monitoring) were identified. The incidence of awareness in studies with and without RRS was determined and compared with Chi-Square analysis. Results: 25 studies from 1987-2008 were identified. 16 were identified as low and average risk, 10 as high risk (one study contained both and the data could be considered separately). RRS were found in 7 studies, 3 low/average risk and 4 high risk. The median incidence of AA in the low/average group was 0.115% (95%CI = 0.19%), or 1 in 870 patients. With the data from all studies pooled, the incidence was 0.074% or 1 in 1,342 patients. In the high risk patients, the median incidence was 0.54% (95% CI = 0.61%) or 1 in 186 patients: with pooled data the incidence was 0.48%, or 1 in 208. Studies utilizing RRS had significantly less AA than those without: in low/average-risk patients (Figure 1) there 4 cases of AA in 96,659 patients (0.004%) compared with 203 cases in 181,204 patients (0.112%), respectively, and in high-risk patients (Figure 2) 10 cases of AA in 6,210 patients (0.16%) compared with 40 cases in 4184 patients (0.96%), respectively (both p<10-5, Chi-Square). Discussion: There appears to be clear benefit in employing risk stratification and risk reduction strategies. With risk reduction, the incidence of AA was significantly decreased compared to historical data. Both anesthesia delivery protocols and processed-EEG monitoring appear effective in reducing the risk of AA. Further randomized controlled studies are required to determine if either approach is superior.[figure1]Figure 1 - Incidence of Anesthesia Awareness in Low-Average Risk Patients (mean + 95%CI)[figure2]Figure 2 - Incidence of Anesthesia Awareness in High Risk Patients (mean + 95%CI). Anesthesiology 2008; 109 A985 |
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