Prevention of Intraoperative Awareness in a High-Risk Surgical PopulationMichael S. Avidan, M.B., B.Ch., Eric Jacobsohn, M.B., Ch.B., David Glick, M.D., M.B.A., Beth A. Burnside, B.A., Lini Zhang, M.D., Alex Villafranca, M.S., Leah Karl, B.A., Saima Kamal, M.D., Brian Torres, B.S.N., Michael O'Connor, M.D., Alex S. Evers, M.D., Stephen Gradwohl, B.S., Nan Lin, Ph.D., Ben J. Palanca, M.D., Ph.D., and George A. Mashour, M.D., Ph.D. for the BAG-RECALL Research Group.N Engl J Med 2011; 365:591-600August 18, 2011
BackgroundUnintended intraoperative awareness, which occurs when general anesthesia is not achieved or maintained, affects up to 1% of patients at high risk for this complication. We tested the hypothesis that a protocol incorporating the electroencephalogram-derived bispectral index (BIS) is superior to a protocol incorporating standard monitoring of end-tidal anesthetic-agent concentration (ETAC) for the prevention of awareness.MethodsWe conducted a prospective, randomized, evaluator-blinded trial at three medical centers. We randomly assigned 6041 patients at high risk for awareness to BIS-guided anesthesia (with an audible alert if the BIS value was <40 or >60, on a scale of 0 to 100, with 0 indicating the suppression of detectable brain electrical activity and 100 indicating the awake state) or ETAC-guided anesthesia (with an audible alert if the ETAC was <0.7 or >1.3 minimum alveolar concentration). In addition to audible alerts, the protocols included structured education and checklists. Superiority of the BIS protocol was assessed with the use of a one-sided Fisher's exact test.ResultsA total of 7 of 2861 patients (0.24%) in the BIS group, as compared with 2 of 2852 (0.07%) in the ETAC group, who were interviewed postoperatively had definite intraoperative awareness (a difference of 0.17 percentage points; 95% confidence interval [CI], −0.03 to 0.38; P=0.98). Thus, the superiority of the BIS protocol was not demonstrated. A total of 19 cases of definite or possible intraoperative awareness (0.66%) occurred in the BIS group, as compared with 8 (0.28%) in the ETAC group (a difference of 0.38 percentage points; 95% CI, 0.03 to 0.74; P=0.99), with the superiority of the BIS protocol again not demonstrated. There was no difference between the groups with respect to the amount of anesthesia administered or the rate of major postoperative adverse outcomes.ConclusionsThe superiority of the BIS protocol was not established; contrary to expectations, fewer patients in the ETAC group than in the BIS group experienced awareness. (Funded by the Foundation for Anesthesia Education and Research and others; BAG-RECALL ClinicalTrials.gov number, NCT00682825.) Drug therapy for treating post-dural puncture headache.
Emergency Department, Hospital de Figueres, Fundació Salut Empordà , Rda Rector Aroles s/n, Figueres, Girona-Catalunya, Spain, 17600.Cochrane Database Syst Rev. 2011 Aug 10;(8):CD007887
Abstract
BACKGROUND:
Post-dural puncture headache (PDPH) is the most common complication of lumbar puncture, an invasive procedure frequently performed in the emergency room. Numerous pharmaceutical drugs have been proposed to treat PDPH but there are still some uncertainties about their clinical effectiveness.
OBJECTIVES:
To assess the effectiveness and safety of drugs for treating PDPH in adults and children.
SEARCH STRATEGY:
The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2011, Issue 2), MEDLINE (from 1950 to June 2011), EMBASE (from 1980 to June 2011) and CINAHL (from 1982 to June 2011). There was no language restriction.
SELECTION CRITERIA:
We considered randomised controlled trials (RCTs) assessing the effectiveness of any pharmacological drug used for treating PDPH.
DATA COLLECTION AND ANALYSIS:
Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because the included studies assessed different sorts of drugs or different outcomes. We performed an intention-to-treat (ITT) analysis.
MAIN RESULTS:
We included seven RCTs (200 participants) in this review (between 88% and 90.5% were women; mostly parturients (84% to 87%) after a lumbar puncture for a regional anaesthesia). Pharmacological drugs assessed were oral and intravenous caffeine, subcutaneous sumatriptan, oral gabapentin, oral theophylline, intravenous hydrocortisone and intramuscular adrenocorticotropic hormone (ACTH).One RCT reported data about PDPH persistence of any severity at follow up (primary outcome); caffeine reduced the number of participants with PDPH at one to two hours when compared to placebo. Treatment with caffeine also decreased the need for a conservative supplementary therapeutic option. Treatment with gabapentin versus placebo reported better visual analogue scale (VAS) scores after one, two, three and four days; treatment with hydrocortisone plus conventional treatment showed better VAS scores than conventional treatment alone at six, 24 and 48 hours and treatment with theophylline showed a lower mean "sum of pain" when compared with placebo. Sumatriptan and ACTH did not show any relevant effect for this outcome.There were no clinically significant drug adverse events.The rest of the outcomes were not reported by the RCTs or did not show any relevant effect.
AUTHORS' CONCLUSIONS:
Caffeine has shown effectiveness for treating PDPH, decreasing the proportion of participants with PDPH persistence and those requiring supplementary interventions, when compared with placebo. Gabapentin, theophylline and hydrocortisone have also shown a decrease in pain severity scores when compared with placebo or conventional care.There is a lack of conclusive evidence for the other drugs assessed (sumatriptan and ACTH).These conclusions should be interpreted with caution, due to the lack of information to allow correct appraisal of risk of bias, the small sample sizes of studies and also the limited generalisability, as most participants were post-partum women in their 30s
Appropriate length of epidural catheter in the epidural space for postoperative analgesia: evaluation by epidurography
Correspondence: Dr G. Afshan
Email: gauhar.afshan@aku.edu
Anaesthesia 2011; 66(10): 913-8
Summary
In current practice, the length of epidural catheter that should be left in the epidural space is not standardised for effective postoperative analgesia. This prospective, randomised, double‐blinded study aimed to determine the most appropriate length of epidural catheter that should be inserted into the epidural space for postoperative analgesia. We recruited 102 women and assigned them into three study groups (3, 5 and 7 cm insertion). An epidural catheter was inserted and epidurography was performed. Postoperatively, mean pain scores, motor and sensory levels, and any complications associated with the epidural catheter were recorded. No statistically significant difference for mean postoperative pain score was found at all study timings. Motor and sensory blockade was also statistically insignificant. Unilateral sensory analgesia developed in one patient in the 7 cm group and epidural catheter dislodgement was observed in four patients in the 3 cm group. In order to minimise catheter‐related complications for postoperative analgesia, the most appropriate length that an epidural catheter should be left in the epidural space is 5 cm.
Preoperative anaemia and postoperative outcomes in non-cardiac surgery: a retrospective cohort study.
Musallam KM, Tamim HM, Richards T, Spahn DR, Rosendaal FR, Habbal A, Khreiss M, Dahdaleh FS, Khavandi K, Sfeir PM, Soweid A, Hoballah JJ, Taher AT, Jamali FR.Source
Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.Abstract
BACKGROUND:
Preoperative anaemia is associated with adverse outcomes after cardiac surgery but outcomes after non-cardiac surgery are not well established. We aimed to assess the effect of preoperative anaemia on 30-day postoperative morbidity and mortality in patients undergoing major non-cardiac surgery.
METHODS:
We analysed data for patients undergoing major non-cardiac surgery in 2008 from The American College of Surgeons' National Surgical Quality Improvement Program database (a prospective validated outcomes registry from 211 hospitals worldwide in 2008). We obtained anonymised data for 30-day mortality and morbidity (cardiac, respiratory, CNS, urinary tract, wound, sepsis, and venous thromboembolism outcomes), demographics, and preoperative and perioperative risk factors. We used multivariate logistic regression to assess the adjusted and modified (nine predefined risk factor subgroups) effect of anaemia, which was defined as mild (haematocrit concentration >29-<39% in men and >29-<36% in women) or moderate-to-severe (≤29% in men and women) on postoperative outcomes.
FINDINGS:
We obtained data for 227,425 patients, of whom 69,229 (30·44%) had preoperative anaemia. After adjustment, postoperative mortality at 30 days was higher in patients with anaemia than in those without anaemia (odds ratio [OR] 1·42, 95% CI 1·31-1·54); this difference was consistent in mild anaemia (1·41, 1·30-1·53) and moderate-to-severe anaemia (1·44, 1·29-1·60). Composite postoperative morbidity at 30 days was also higher in patients with anaemia than in those without anaemia (adjusted OR 1·35, 1·30-1·40), again consistent in patients with mild anaemia (1·31, 1·26-1·36) and moderate-to-severe anaemia (1·56, 1·47-1·66). When compared with patients without anaemia or a defined risk factor, patients with anaemia and most risk factors had a higher adjusted OR for 30-day mortality and morbidity than did patients with either anaemia or the risk factor alone.
INTERPRETATION:
Preoperative anaemia, even to a mild degree, is independently associated with an increased risk of 30-day morbidity and mortality in patients undergoing major non-cardiac surgery
Lancet. 2011 Oct 15;378(9800):1362-3.
Prevention of Intraoperative Awareness in a High-Risk Surgical Population
Michael S. Avidan, M.B., B.Ch., Eric Jacobsohn, M.B., Ch.B., David Glick, M.D., M.B.A., Beth A. Burnside, B.A., Lini Zhang, M.D., Alex Villafranca, M.S., Leah Karl, B.A., Saima Kamal, M.D., Brian Torres, B.S.N., Michael O'Connor, M.D., Alex S. Evers, M.D., Stephen Gradwohl, B.S., Nan Lin, Ph.D., Ben J. Palanca, M.D., Ph.D., and George A. Mashour, M.D., Ph.D. for the BAG-RECALL Research Group.
N Engl J Med 2011; 365:591-600August 18, 2011
Background
Unintended intraoperative awareness, which occurs when general anesthesia is not achieved or maintained, affects up to 1% of patients at high risk for this complication. We tested the hypothesis that a protocol incorporating the electroencephalogram-derived bispectral index (BIS) is superior to a protocol incorporating standard monitoring of end-tidal anesthetic-agent concentration (ETAC) for the prevention of awareness.
Methods
We conducted a prospective, randomized, evaluator-blinded trial at three medical centers. We randomly assigned 6041 patients at high risk for awareness to BIS-guided anesthesia (with an audible alert if the BIS value was <40 or >60, on a scale of 0 to 100, with 0 indicating the suppression of detectable brain electrical activity and 100 indicating the awake state) or ETAC-guided anesthesia (with an audible alert if the ETAC was <0.7 or >1.3 minimum alveolar concentration). In addition to audible alerts, the protocols included structured education and checklists. Superiority of the BIS protocol was assessed with the use of a one-sided Fisher's exact test.
Results
A total of 7 of 2861 patients (0.24%) in the BIS group, as compared with 2 of 2852 (0.07%) in the ETAC group, who were interviewed postoperatively had definite intraoperative awareness (a difference of 0.17 percentage points; 95% confidence interval [CI], −0.03 to 0.38; P=0.98). Thus, the superiority of the BIS protocol was not demonstrated. A total of 19 cases of definite or possible intraoperative awareness (0.66%) occurred in the BIS group, as compared with 8 (0.28%) in the ETAC group (a difference of 0.38 percentage points; 95% CI, 0.03 to 0.74; P=0.99), with the superiority of the BIS protocol again not demonstrated. There was no difference between the groups with respect to the amount of anesthesia administered or the rate of major postoperative adverse outcomes.
Conclusions
The superiority of the BIS protocol was not established; contrary to expectations, fewer patients in the ETAC group than in the BIS group experienced awareness. (Funded by the Foundation for Anesthesia Education and Research and others; BAG-RECALL ClinicalTrials.gov number, NCT00682825.)
Drug therapy for treating post-dural puncture headache.
Emergency Department, Hospital de Figueres, Fundació Salut Empordà , Rda Rector Aroles s/n, Figueres, Girona-Catalunya, Spain, 17600.
Cochrane Database Syst Rev. 2011 Aug 10;(8):CD007887
Abstract
BACKGROUND:
Post-dural puncture headache (PDPH) is the most common complication of lumbar puncture, an invasive procedure frequently performed in the emergency room. Numerous pharmaceutical drugs have been proposed to treat PDPH but there are still some uncertainties about their clinical effectiveness.OBJECTIVES:
To assess the effectiveness and safety of drugs for treating PDPH in adults and children.SEARCH STRATEGY:
The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2011, Issue 2), MEDLINE (from 1950 to June 2011), EMBASE (from 1980 to June 2011) and CINAHL (from 1982 to June 2011). There was no language restriction.SELECTION CRITERIA:
We considered randomised controlled trials (RCTs) assessing the effectiveness of any pharmacological drug used for treating PDPH.DATA COLLECTION AND ANALYSIS:
Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because the included studies assessed different sorts of drugs or different outcomes. We performed an intention-to-treat (ITT) analysis.MAIN RESULTS:
We included seven RCTs (200 participants) in this review (between 88% and 90.5% were women; mostly parturients (84% to 87%) after a lumbar puncture for a regional anaesthesia). Pharmacological drugs assessed were oral and intravenous caffeine, subcutaneous sumatriptan, oral gabapentin, oral theophylline, intravenous hydrocortisone and intramuscular adrenocorticotropic hormone (ACTH).One RCT reported data about PDPH persistence of any severity at follow up (primary outcome); caffeine reduced the number of participants with PDPH at one to two hours when compared to placebo. Treatment with caffeine also decreased the need for a conservative supplementary therapeutic option. Treatment with gabapentin versus placebo reported better visual analogue scale (VAS) scores after one, two, three and four days; treatment with hydrocortisone plus conventional treatment showed better VAS scores than conventional treatment alone at six, 24 and 48 hours and treatment with theophylline showed a lower mean "sum of pain" when compared with placebo. Sumatriptan and ACTH did not show any relevant effect for this outcome.There were no clinically significant drug adverse events.The rest of the outcomes were not reported by the RCTs or did not show any relevant effect.AUTHORS' CONCLUSIONS:
Caffeine has shown effectiveness for treating PDPH, decreasing the proportion of participants with PDPH persistence and those requiring supplementary interventions, when compared with placebo. Gabapentin, theophylline and hydrocortisone have also shown a decrease in pain severity scores when compared with placebo or conventional care.There is a lack of conclusive evidence for the other drugs assessed (sumatriptan and ACTH).These conclusions should be interpreted with caution, due to the lack of information to allow correct appraisal of risk of bias, the small sample sizes of studies and also the limited generalisability, as most participants were post-partum women in their 30sSource
Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.Abstract
BACKGROUND:
Preoperative anaemia is associated with adverse outcomes after cardiac surgery but outcomes after non-cardiac surgery are not well established. We aimed to assess the effect of preoperative anaemia on 30-day postoperative morbidity and mortality in patients undergoing major non-cardiac surgery.METHODS:
We analysed data for patients undergoing major non-cardiac surgery in 2008 from The American College of Surgeons' National Surgical Quality Improvement Program database (a prospective validated outcomes registry from 211 hospitals worldwide in 2008). We obtained anonymised data for 30-day mortality and morbidity (cardiac, respiratory, CNS, urinary tract, wound, sepsis, and venous thromboembolism outcomes), demographics, and preoperative and perioperative risk factors. We used multivariate logistic regression to assess the adjusted and modified (nine predefined risk factor subgroups) effect of anaemia, which was defined as mild (haematocrit concentration >29-<39% in men and >29-<36% in women) or moderate-to-severe (≤29% in men and women) on postoperative outcomes.FINDINGS:
We obtained data for 227,425 patients, of whom 69,229 (30·44%) had preoperative anaemia. After adjustment, postoperative mortality at 30 days was higher in patients with anaemia than in those without anaemia (odds ratio [OR] 1·42, 95% CI 1·31-1·54); this difference was consistent in mild anaemia (1·41, 1·30-1·53) and moderate-to-severe anaemia (1·44, 1·29-1·60). Composite postoperative morbidity at 30 days was also higher in patients with anaemia than in those without anaemia (adjusted OR 1·35, 1·30-1·40), again consistent in patients with mild anaemia (1·31, 1·26-1·36) and moderate-to-severe anaemia (1·56, 1·47-1·66). When compared with patients without anaemia or a defined risk factor, patients with anaemia and most risk factors had a higher adjusted OR for 30-day mortality and morbidity than did patients with either anaemia or the risk factor alone.INTERPRETATION:
Preoperative anaemia, even to a mild degree, is independently associated with an increased risk of 30-day morbidity and mortality in patients undergoing major non-cardiac surgeryLancet. 2011 Oct 15;378(9800):1362-3.
Ultrasound Assessment of the Vertebral Level of the Intercristal Line in Pregnancy
A & A September 2011 vol. 113 no. 3 559-564
Abstract
BACKGROUND: The intercristal line is known to most frequently cross the L4 spinous process or L4-5 interspace; however, it is speculated to be positioned higher during pregnancy because of the exaggerated lumbar lordosis. Clinical estimation of vertebral levels relying on the use of the intercristal line has been shown to often be inaccurate. We hypothesized that the vertebral level of the intercristal line determined by palpation would be higher than the level determined by ultrasound in pregnant women.
METHODS: Fifty-one term pregnant patients were recruited. Two experienced anesthesiologists performed estimates of the position of the intercristal line by palpation. Using ultrasound, another anesthesiologist who was blinded to the clinical estimates, determined the position of the superior border of the iliac crest in the transverse and longitudinal planes and then identified the lumbar vertebral levels. The vertebral level at which the clinical estimates of the intercristal line crossed the spine was recorded and compared with the ultrasound-determined level of the superior border of the iliac crest.
RESULTS: The clinical estimates of the spinal level of the intercristal line agreed with the ultrasound measurement 14% of the time (14 of 101; 95% confidence interval [CI]: 8%, 22%). The clinical estimates were 1 level higher than the ultrasound measurement 23% of the time (23 of 101; 95% CI: 16%, 32%) and >1 level higher 25% of the time (25 of 101; 1-tailed 95% CI: >18%). The distribution of the clinical estimates found clinicians locating the intercristal line at L3 or L3-4 54% of the time (54 of 101; 95% CI: 44%, 63%) and at L2-3 or higher 27% of the time (27 of 101; 1-tailed 95% CI: >20%).
CONCLUSION: The anatomical position of the intercristal line was at L3 or higher in at least 6% of term pregnant patients using ultrasound. Clinical estimates were found to be ≥1 vertebral level higher than the anatomical position determined by ultrasound at least 40% of the time. This disparity may contribute to misidentification of lumbar interspaces and increased risk of neurologic injury during neuraxial anesthesia.