Volume 8, Issue 3 S A M B A T A L K S - PAGE 3 August, 2008

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

Listening to Music During Anesthesia Does Not Reduce the Sevoflurane Concentration Needed to Maintain a Constant Bispectral Index.
Szmuk, Peter, Aroyo, Nimrod, Ezri, Tiberiu, Muzikant, Gleb, Weisenberg, Marian, Sessler, Daniel
Anesthesia & Analgesia. 107(1):77-80, July 2008.

BACKGROUND: Music reduces stress responses in awake subjects. However, there remains controversy about the role of music or therapeutic suggestions during general anesthesia and postoperative recovery. We thus tested the hypothesis that intraoperative exposure to soothing music reduces the end-tidal concentration of sevoflurane (ETSevo) necessary to maintain bispectral index (BIS) near 50 during laparoscopic surgery.
METHODS: Forty patients, aged 40-60 yrs, ASA I and II, undergoing laparoscopic hernias or cholecystectomy under general anesthesia were studied. All patients were connected to a BIS monitor. Anesthesia was induced with fentanyl 2 [mu]g/kg, sevoflurane in oxygen, rocuronium (0.6 mg/kg), and maintained with sevoflurane in oxygen and 50% nitrous oxide, with an infusion of fentanyl (1 [mu]g [middle dot] kg-1 [middle dot] h-1). Sevoflurane was titrated to maintain BIS near 50 throughout the procedure. Patients were randomly assigned to either listen to music or not.
RESULTS: The ETSevo necessary to maintain a BIS near 50 was virtually identical in patients who listened to music (1.29 +/- 0.33%) and those who did not (1.27 +/- 0.33%, P = 0.84). Patients who listened to music reported slightly less pain, but the difference was not statistically significant. Mean arterial blood pressure was slightly higher in patients who listened to music (101 +/- 11 mm Hg) than in those who did not (94 +/- 10 mm Hg, P = 0.040).
CONCLUSIONS: The end-tidal concentration of sevoflurane required to maintain BIS near 50 during laparoscopic cholecystectomy was virtually identical in patients exposed to music or not. Although previous work suggests that music reduces preoperative stress and may be useful during sedation, our results do not support the use of music during surgery.

Intraarticular Tramadol-Bupivacaine Combination Prolongs the Duration of Postoperative Analgesia After Outpatient Arthroscopic Knee Surgery.
Zeidan, Ahed, Kassem, Rida, Nahleh, Nazih, Maaliki, Hilal, El-khatib, Mohamad, Struys, Michel, MD, PhD, Baraka, Anis, MD, FRCA
Anesthesia & Analgesia. 107(1):292-299, July 2008.

BACKGROUND: Intraarticular (IA) local anesthetics are often used for the management and prevention of pain after arthroscopic knee surgery. Recently, IA tramadol was also used for the management of these patients. However, the IA combination of local anesthetic and tramadol has not been evaluated in arthroscopic outpatients. Our primary aim in this study was to evaluate the analgesic effect of an IA combination of bupivacaine and tramadol when compared with each drug alone using visual analog scale (VAS) pain scores in patients undergoing day-care arthroscopic knee surgery. Additionally, we assessed analgesic demand.
METHODS: Ninety ASA I/II patients undergoing arthroscopic partial meniscectomy, performed by a single surgeon under general anesthesia, were assigned in a randomized, double-blind manner into three groups: group B (n = 30) received 0.25% bupivacaine, group T (n = 30) received 100 mg tramadol, and group BT (n = 30) received 0.25% bupivacaine and 100 mg tramadol to a total volume of 20 mL by the IA route after surgery. Postoperative pain scores were measured on a VAS, at rest and on mobilization at 0.5, 1, 2, 4, 6, 8, 12, and 24 h. Duration of analgesia, the subsequent 24 h consumption of rescue analgesia, time to ambulation, and time to discharge were evaluated. In addition, the systemic side effects of the IA injected drugs were also assessed.
RESULTS: The results showed significantly lower VAS pain scores in group BT (P << 0.1) when compared with groups T and B. Group BT had a later onset of postsurgical pain and longer time to first rescue analgesic than groups B and T. The 24 h consumption of analgesic was significantly less in group BT when compared with the other two groups (26.7% of the patients required rescue analgesia in group BT, whereas this number was 90% in group B and 86.7% in group T). In addition, time in hours to discharge and time to unassisted ambulation were significantly shorter in group BT when compared with groups T and B, and this was not associated with any detectable systemic effects.
CONCLUSION: The IA admixture of tramadol 100 mg with bupivacaine 0.25% provides a pronounced prolongation of analgesia compared with either drug alone in patients undergoing day care arthroscopic knee surgery.

Antiemetic Prophylaxis for Postdischarge Nausea and Vomiting and Impact on Functional Quality of Living During Recovery in Patients with High Emetic Risks: A Prospective, Randomized, Double-Blind Comparison of Two Prophylactic Antiemetic Regimens.
Pan, Peter, MSEE, MD, Lee, Sherman, Harris, Lynne
Anesthesia & Analgesia. 107(2):429-438, August 2008.

BACKGROUND: We compared two antiemetic prophylaxis regimens, their efficacy for preventing postdischarge nausea and vomiting, and their impact on quality of living, during recovery.
METHODS: Sixty-four women undergoing outpatient gynecological surgery and at high risk for emesis were randomized into one of two groups. The study group received intraoperative IV dexamethasone 8 mg and ondansetron 4 mg, followed with an 8 mg oral disintegrating ondansetron tablet, to be taken on discharge and in the morning of postoperative days 1 and 2. The control group received only the IV ondansetron 4 mg intraoperatively. The incidence and severity of emetic symptoms and pain were assessed while patients were in the recovery room and via telephone and patient diary for 5 days after discharge. A modified functional living index of emesis was used to assess the impact on quality of living during recovery.
RESULTS: Sixty patients, 30 in each group, completed the study. The incidences for postdischarge nausea were 57% and 20%, and for postdischarge vomiting 20% and 3% in the control and study groups, respectively, for the period between the 8th and 120th hours postanesthesia (P < 0.05). Thirty-three percent of the study and 60% of the control group reported that emetic symptoms negatively affected their quality of living (P < 0.05).
CONCLUSIONS: When compared with a single dose of intraoperative IV ondansetron prophylaxis, our study regimen of additional intraoperative dexamethasone and once a day ondansetron significantly reduced the incidence of postdischarge nausea and vomiting and its negative impact on quality of living during the first 5 days of recovery.

A Randomized, Double-Blind Study to Evaluate the Efficacy and Safety of Three Different Doses of Palonosetron Versus Placebo in Preventing Postoperative Nausea and Vomiting Over a 72-Hour Period.
Kovac, Anthony, Eberhart, Leopold, Kotarski, Jan, Clerici, Giuseppina, Apfel, Christian, MD, PhD
Anesthesia & Analgesia. 107(2):439-444, August 2008.

BACKGROUND: We designed this multicenter, randomized, double-blind study to assess the efficacy and safety of three doses of palonosetron, compared with placebo, on the incidence and severity of postoperative nausea and vomiting (PONV) in inpatients for 72 h after surgery.
METHODS: Female patients undergoing either elective gynecological or breast surgery were stratified according to two additional PONV risk factors: nonsmoking status and history of PONV and/or motion sickness. Five hundred forty-four patients with one or both of these risk factors were randomized to receive one of the three doses of IV palonosetron (0.025 mg, 0.050 mg, 0.075 mg) or placebo immediately before induction of anesthesia. The primary efficacy end-point was complete response (CR: no emesis and no use of rescue medications) evaluated at the 0-24 and 24-72 h time intervals after surgery.
RESULTS: CR rates for placebo and palonosetron 0.075 mg were 36% and 56% for 0-24 h (P = 0.001), 52% and 70% for 24-72 h (P = 0.002) and 36% and 52% (P = 0.010) for the 0-72 h postoperative interval. Palonosetron 0.075 mg was associated with less intense nausea (e.g., toward "mild" or "none") versus placebo during the 0-24 h (P < 0.001) time interval and significantly delayed median time to emesis (P = 0.002) and treatment failure (P = 0.004). Although CR rates for both the 0.025 mg and 0.050 mg palonosetron doses were not statistically superior to placebo for the 0-24 h or 24-72 h periods, both lower doses reduced nausea severity during the 0-24 h period (P = 0.040 and P = 0.004).
CONCLUSION: A single 0.075-mg IV dose of palonosetron effectively reduced the severity of nausea and delayed the time to emesis and treatment failure in the inpatient surgical setting; lower doses were not as effective.

A Randomized, Double-Blind Study to Evaluate the Efficacy and Safety of Three Different Doses of Palonosetron Versus Placebo for Preventing Postoperative Nausea and Vomiting.
Candiotti, Keith, Kovac, Anthony, Melson, Timothy, Clerici, Giuseppina, Joo Gan, Tong, MB, FRCA
Anesthesia & Analgesia. 107(2):445-451, August 2008.

BACKGROUND: In this randomized, double-blind study we assessed the efficacy and safety of three different doses of the 5-HT3 receptor antagonist palonosetron, compared with placebo, on the incidence and severity of postoperative nausea and vomiting (PONV) for 72 h postsurgery.
METHODS: Five hundred seventy-four patients undergoing either outpatient abdominal or gynecological laparoscopic surgery were stratified according to gender, history of PONV or motion sickness, and nonsmoking status. Patients with >=2 PONV risk factors were eligible and randomized to receive one of three doses of IV palonosetron (0.025 mg, 0.050 mg, or 0.075 mg) or placebo immediately prior to induction of anesthesia. Co-primary efficacy end-points included complete response (CR: no emetic episodes and no rescue medication) during the 0 to 24 h and 24 to 72 h postoperative time intervals.
RESULTS: A dose-response trend in the proportion of patients with a CR was observed with increasing doses of palonosetron in the first 24 hrs. CR rates for placebo and palonosetron 0.075 mg were 26% and 43%, respectively, for the 0 to 24 h postoperative interval (P = 0.004), and 41% and 49%, respectively, for the 24 to 72 h interval (P = 0.188). Compared with placebo, palonosetron 0.075 mg was associated with a significant downward shift toward less intense nausea (P = 0.042) and with significant reduction in the impact of PONV on patient functioning (P = 0.004) during the 0 to 24 h interval.
CONCLUSIONS: A single 0.075-mg IV dose of palonosetron significantly increased the CR rate (no emetic episodes and no rescue medication) from 0 to 24 h, decreased nausea severity and patients experienced significantly less interference in their postoperative function due to PONV.

The Impact of Current Antiemetic Practices on Patient Outcomes: A Prospective Study on High-Risk Patients.
White, Paul, PhD, MD, O'Hara, Jerome, Roberson, Charles, Wender, Ronald, Candiotti, Keith
Anesthesia & Analgesia. 107(2):452-458, August 2008.

BACKGROUND: In this prospective, multicenter, observational study, we evaluated the incidence and time course of postoperative nausea and vomiting (PONV), assessed prophylactic and rescue antiemetic use in high-risk patients, and determined population-based effectiveness of antiemetics, including the impact of American Society of Anesthesiologists (ASA) and American Society of Perianesthesia Nurses (ASPAN) guideline compliance.
METHODS: Eligible patients undergoing elective laparoscopic or major plastic surgery possessed two or more of the following Apfel PONV risk factors: female gender, history of PONV or motion sickness, and nonsmoking status. Antiemetic use, emetic episodes, severity of nausea, and functional interference due to PONV were documented during the first 72 h after surgery. Complete response (CR) was defined as no emesis or rescue medication use, and complete control was defined as CR and no moderate-severe nausea. The effect of compliance (versus noncompliance) with ASA and ASPAN guidelines on PONV outcomes was also analyzed.
RESULTS: The proportion of patients experiencing postoperative emesis ranged from 18% to 40% depending on the number of antiemetics administered. The rate of rescue medication (45%) was similar to the reported incidences of moderate-to-severe nausea (47%) and functional interference due to emetic symptoms (44%). The administration of three or more antiemetics produced better patient outcomes overall compared to <1 prophylactic antiemetic. CR rates were <70% despite adherence to current organizational PONV management guidelines (ASA: 69%; ASPAN: 63%). The complete control rates were 10% lower than CR rates over the 3 day study period.
CONCLUSIONS: Administration of three or more prophylactic antiemetics had the most positive impact on emetic outcomes over 72 hrs in patients at risk of developing PONV. Although compliance with organizational PONV management guidelines improved patient outcomes, postoperative emetic symptoms and interference with patient functioning still occurred in more than 30% of these high-risk patients.

The Relationship Between Patient Risk Factors and Early Versus Late Postoperative Emetic Symptoms.
White, Paul, PhD, MD, Sacan, Ozlem, Nuangchamnong, Nina, Sun, Tiffany, Eng, Matthew
Anesthesia & Analgesia. 107(2):459-463, August 2008.

BACKGROUND: Postoperative nausea and vomiting (PONV) remain common complications after elective surgery. Prophylactic antiemetic drugs are frequently administered to patients with well known risk factors for developing PONV. We designed this prospective observational study to assess the relationship between common patient risk factors for developing PONV and the occurrence of early (0-24 h) versus late (24-72 h) emetic symptoms.
METHODS: One hundred thirty patients undergoing elective laparoscopic (n = 88) or plastic (n = 42) surgery were assigned a risk score for developing PONV based on the Apfel risk scoring system, which assigns one point each for female gender, nonsmoking status, history of PONV or motion sickness, and postoperative opioid use. It was assumed that all patients would receive an opioid analgesic in the postoperative period. The patients received 0, 1, 2, or 3 antiemetic drugs for prophylaxis. The occurrence of nausea, vomiting, and need for rescue antiemetics was assessed at specific time intervals from 0 to 6, 6-24, and 24-72 h after surgery. In addition, the impact of PONV on recovery of normal activities of daily living was assessed using a standardized patient questionnaire.
RESULTS: One or more prophylactic antiemetics were administered to 87%, 90%, and 95% of the patients in the two, three, and four Apfel risk-factor groups, respectively. In the presence of three or four risk factors, >=2 antiemetics were administered to 56% and 75% of the patients, respectively. Vomiting was reported in 11% and 22% of patients in the three and four risk factor groups compared with 6% in the two risk factor group at 0-6 h, and 13% and 27% (vs 0%) at 6-24 h, respectively. However, in the 24-72 h postoperative period, the incidences of emesis were low and did not differ in the three risk groups (9%, 5%, and 11%, respectively). The occurrence of moderate-to-severe nausea was increased in the higher risk groups at 0-6 h and 6-24 h (19%-28% vs 6% and 20%-30% vs 9%, respectively). However, the incidences of nausea in the 24-72 h period in the three and four risk factor groups were not different from the two-risk factor group (5% and 8% vs 6%, respectively). The need for rescue antiemetics and interference of emetic symptoms with normal activities was greater in the four risk factor group compared with the two and three risk factor groups.
CONCLUSION: Despite the frequent use of multiple antiemetic drugs for prophylaxis, an Apfel risk score of three or four (vs 2) was associated with a higher incidence of emetic sequelae in the first 24 h after surgery. However, the occurrence of late (24-72 h) emetic symptoms was low and appeared to be unrelated to the patient's Apfel risk score.

Palonosetron Exhibits Unique Molecular Interactions with the 5-HT3 Receptor.
Rojas, Camilo, Stathis, Marigo, Thomas, Ajit, Massuda, Edward, Alt, Jesse, Zhang, Jie, Rubenstein, Ed, Sebastiani, Silvia, Cantoreggi, Sergio, Snyder, Solomon, Slusher, Barbara
Anesthesia & Analgesia. 107(2):469-478, August 2008.

BACKGROUND: Palonosetron is a 5-HT3-receptor antagonist (5-HT3-RA) that has been shown to be superior to other 5-HT3-RAs in phase III clinical trials for the prevention of acute, delayed, and overall chemotherapy-induced nausea and vomiting. The improved clinical efficacy of palonosetron may be due, in part, to its more potent binding and longer half-life. However, these attributes alone are not sufficient to explain the results with palonosetron. We sought to elucidate additional differences among 5-HT3-RAs that could help explain the observations in the clinic.
METHODS: Receptor site saturation binding experiments were performed with [3H] palonosetron, [3H] granisetron, and [3H] ondansetron to obtain the corresponding Scatchard analyses and Hill coefficients. Diagnostic equilibrium binding experiments and kinetic dissociation experiments were conducted to examine competitive versus potential allosteric interactions between ondansetron, granisetron and palonosetron and the 5-HT3 receptor. Finally, the long-term effect of the three antagonists on receptor function as measured by Ca2+ influx in HEK 293 cells expressing the 5-HT3-receptor was compared.
RESULTS: Analyses of binding isotherms using both Scatchard and Hill plots suggested positive cooperativity for palonosetron and simple bimolecular binding for both granisetron and ondansetron. Equilibrium diagnostic tests discriminated differential effects of palonosetron on [3H] ligand binding indicating that palonosetron was an allosteric antagonist whereas granisetron and ondansetron were competitive antagonists. Using dissociation rate strategies, palonosetron was shown to be an allosteric modifier that accelerated the rate of dissociation from the receptor of both granisetron and ondansetron. Differences in the binding mode of palonosetron to the 5-HT3 receptor were shown to have an impact on receptor function. In these experiments, cells were incubated with each antagonist, followed by infinite dilutions and dissociation for 2.5 h; cells previously incubated with either granisetron or ondansetron showed calcium-ion influx similar to control cells that had not been exposed to a 5-HT3 receptor antagonist. In contrast, substantial inhibition of calcium-ion influx was observed in cells that had been incubated with palonosetron.
CONCLUSIONS: Palonosetron exhibited allosteric binding and positive cooperativity when binding to the 5-HT3 receptor. Palonosetron also triggered functional effects that persisted beyond its binding to the 5-HT3 receptor at the cell surface. Differences in binding and effects on receptor function may be relevant to the unique beneficial actions of palonosetron. To our knowledge, this is the first report showing palonosetron's interaction with the 5-HT3 receptor at the molecular level, clearly differentiating it from other 5-HT3-RAs.

High-throughput Operating Room System for Joint Arthroplasties Durably Outperforms Routine Processes.
Perioperative Medicine
Smith, Michael P. M.D., M.S.Ed. ; Sandberg, Warren S. M.D., Ph.D. ; Foss, Joseph M.D. ; Massoli, Kathleen C.R.N.A. ; Kanda, Mona M.D. ; Barsoum, Wael M.D. ; Schubert, Armin M.D., M.B.A. 
Anesthesiology. 109(1):25-35, July 2008.

Abstract:
Background: Recent publications have focused on increased operating room (OR) throughput without increasing total OR time. The authors hypothesized that a system of parallel processing for lower extremity joint arthroplasties sustainably reduces nonoperative time and increases throughput.
Methods: The high-throughput parallel processing strategy included neuraxial anesthesia performed in an "induction room" adjacent to the OR, patient selection, an additional circulating nurse, and end-of-case transfer of care to a recovery room nurse who transported the patient from the OR to recovery. Instruments and supplies were prepared in a dedicated sterile setup area. Data were extracted from administrative databases. Group comparisons used standard statistical methods; statistical process control was used to evaluate performance over time.
Results: There were 688 historic control cases from 299 days over 16 months, and 905 high-throughput cases from 304 days spanning 24 consecutive months starting September 1, 2004. Throughput increased from 2.6 +/- 0.7 (mean +/- SD) to 3.4 +/- 0.8 arthroplasties per day per room. Nonoperative time decreased by 36 min (or 50%) per case. Operative time also decreased by 14 min (12%) per case. The end time for the high-throughput OR day was only 16 min later than control. Nonoperative time, operative time, and throughput remained significantly improved after 2 yr of operation. Contribution margin increased 19.6%.
Conclusion: Reorganizing the perioperative work process for total joint replacements sustainably increased OR throughput. Because joint arthroplasties generated a positive margin greater than the incremental cost, the high-throughput system improved financial performance.

Randomized Prospective Study Comparing the Laryngeal Tube Suction II with the ProSeal(TM) Laryngeal Mask Airway in Anesthetized and Paralyzed Patients.
Perioperative Medicine
Kikuchi, Tatsuaki M.D., Ph.D. ; Kamiya, Yoshinori M.D., Ph.D. ; Ohtsuka, Tsuyoshi M.D. ; Miki, Tomoko M.D. ; Goto, Takahisa M.D., Ph.D. 
Anesthesiology. 109(1):54-60, July 2008.

Abstract:
Background: The Laryngeal Tube Suction II (LTSII; VBM, Medizintechnik, Sulz, Germany) is a recent revision of the Laryngeal Tube Suction. This study compared insertion and ventilation profiles of the LTSII and the ProSeal(TM) Laryngeal Mask Airway (PLMA(TM); Laryngeal Mask Company, Henley-on-Thames, United Kingdom) in anesthetized and paralyzed patients.
Methods: One hundred adult male patients were randomly allocated to an LTSII or PLMA(TM) group. The rate of successful insertion, insertion time, airway leak pressure at a cuff pressure of 60 cm H2O, tidal volume during pressure-controlled ventilation, incidence of gas leakage with cuff pressure reduced and with the shaft inclined, position of LTSII under fluoroscopic observation, and postoperative airway morbidity were determined.
Results: Insertion was successful in 37 and 48 of 50 patients with LTSII and PLMA(TM), respectively (P = 0.002), with similar insertion times. Tidal volume was lower with LTSII than with PLMA(TM). Median airway leak pressures of LTSII and PLMA(TM) were 16 and 21 cm H2O, respectively (P = 0.006). Gas leakage around the cuff was observed more frequently with LTSII than with PLMA(TM) when the cuff pressure was reduced or the shaft of the device inclined. The position of LTSII varied significantly and did not statistically correlate with patient height. Postoperative airway-related morbidity was not significantly different. Finally, tracheal misplacement of LTSII occurred in 5 of 50 patients (10%), but ventilation was possible in 4 of them, and misplacement was identified only after fluoroscopic examination was performed.
Conclusion: Airway management with LTSII is inferior to that with PLMA(TM).

Lack of Impact of Intravenous Lidocaine on Analgesia, Functional Recovery, and Nociceptive Pain Threshold after Total Hip Arthroplasty.
Pain Medicine
Martin, Frederic M.D. ; Cherif, Kamel M.D. ; Gentili, Marc Emile M.D., Ph.D. ; Enel, Dominique M.D. ; Abe, Emuri Pharm.D. ; Alvarez, Jean Claude Pharm.D., Ph.D. ; Mazoit, Jean Xavier M.D., Ph.D. ; Chauvin, Marcel M.D., Ph.D. ; Bouhassira, Didier M.D., Ph.D. ; Fletcher, Dominique M.D., Ph.D. 
Anesthesiology. 109(1):118-123, July 2008.

Abstract:
Background: The analgesic effect of perioperative low doses of intravenous lidocaine has been demonstrated after abdominal surgery. This study aimed to evaluate whether a continuous intravenous low-dose lidocaine infusion reduced postoperative pain and modified nociceptive pain threshold after total hip arthroplasty.
Methods: Sixty patients participated in this randomized double-blinded study. Patients received lidocaine 1% (lidocaine group) with a 1.5 mg/kg-1 intravenous bolus in 10 min followed by a 1.5 mg [middle dot] kg-1 [middle dot] h-1 intravenous infusion or saline (control group). These regimens were started 30 min before surgical incision and stopped 1h after skin closure. Lidocaine blood concentrations were measured at the end of administration. In both groups, postoperative analgesia was provided exclusively by patient-controlled intravenous morphine. Pain scores, morphine consumption, and operative hip flexion were recorded over 48 h. In addition, pressure pain thresholds and the extent of hyperalgesia around surgical incision were systematically measured at 24 and 48 h.
Results: In comparison with the placebo, lidocaine did not induce any opioid-sparing effect during the first 24 h (median [25-75% interquartile range]; 17 mg [9-28] vs. 15 mg [8-23]; P = 0.54). There was no significant difference regarding the effects of lidocaine and placebo on pain score, pressure pain thresholds, extent in the area of hyperalgesia, and maximal degree of active hip flexion tolerated. Mean plasma lidocaine concentration was 2.1 +/- 0.4 [mu]g/ml.
Conclusion: Low dose perioperative intravenous lidocaine after total hip arthroplasty offers no beneficial effect on postoperative analgesia and does not modify pressure and tactile pain thresholds.

Obesity-induced Insulin Resistance and Hyperglycemia: Etiologic Factors and Molecular Mechanisms.
Review Article
Martyn, J A. Jeevendra M.D., F.R.C.A., F.C.C.M. ; Kaneki, Masao M.D., Ph.D. ; Yasuhara, Shingo M.D., Ph.D. 
Anesthesiology. 109(1):137-148, July 2008.

Abstract:
Obesity is a major cause of type 2 diabetes, clinically evidenced as hyperglycemia. The altered glucose homeostasis is caused by faulty signal transduction via the insulin signaling proteins, which results in decreased glucose uptake by the muscle, altered lipogenesis, and increased glucose output by the liver. The etiology of this derangement in insulin signaling is related to a chronic inflammatory state, leading to the induction of inducible nitric oxide synthase and release of high levels of nitric oxide and reactive nitrogen species, which together cause posttranslational modifications in the signaling proteins. There are substantial differences in the molecular mechanisms of insulin resistance in muscle versus liver. Hormones and cytokines from adipocytes can enhance or inhibit both glycemic sensing and insulin signaling. The role of the central nervous system in glucose homeostasis also has been established. Multipronged therapies aimed at rectifying obesity-induced anomalies in both central nervous system and peripheral tissues may prove to be beneficial.

New Strategies to Detect Alcohol Use Disorders in the Preoperative Assessment Clinic of a German University Hospital.
Perioperative Medicine
Kip, Miriam J. M.D. ; Neumann, Tim M.D. ; Jugel, Constanze ; Kleinwaechter, Robin M.D. ; Weiss-Gerlach, Edith ; Guill, Martin Mac M.D. ; Spies, Claudia D. M.D. 
Anesthesiology. 109(2):171-179, August 2008.

Abstract:
Background: Although alcohol use disorders (AUDs) have enormous public health consequences, the rate of diagnosis of AUDs remains unsatisfactorily low. The primary aim of this study was to compare the detection of AUDs by anesthesiologists in a large preoperative assessment clinic to that by computerized self-assessment of the Alcohol Use Disorder Identification Test. Secondary outcome measures were to compare the actions taken by anesthesiologists upon a finding of an AUD.
Methods: One thousand five hundred fifty-six patients were included. Before preoperative assessment, patients were asked to complete the Alcohol Use Disorder Identification Test (positive scores: men >= 8, women >= 5) using a computer. The authors performed a retrospective chart analysis of the anesthesiologists' actions upon a finding of an AUD. The anesthesiologists were blinded to the results of the computer-based assessment and to the subsequent chart analysis.
Results: The prevalence rate of AUDs determined by the anesthesiologists was 6.9% (107 of 1,556), whereas the proportion of patients positive for an AUD using the computerised Alcohol Use Disorder Identification Test was 18.1% (282 of 1,556) (P < 0.001). The detection rate by the anesthesiologists of AUDs among men was significantly higher than among women (P < 0.001) as well as in the elderly compared with younger patients (P < 0.001). Action taken by anesthesiologists was mainly based on evaluating quantity of alcohol consumption.
Conclusion: The computer-based self-assessment increases detection rates of AUDs in busy settings such as a preoperative assessment clinic. Prevalence rates of AUDs are underestimated. Best-practice guidelines for detection of AUDs are not implemented in the daily clinical routine. Barrier analysis is urgently required.

Remifentanil Modifies the Relation of Electroencephalographic Spectral Changes and Clinical Endpoints in Propofol Anesthesia.
Perioperative Medicine
Kortelainen, Jukka M.Sc. ; Koskinen, Miika Ph.D. ; Mustola, Seppo M.D., Ph.D. ; Seppanen, Tapio Ph.D. 
Anesthesiology. 109(2):198-205, August 2008.

Abstract:
Background: Depth-of-anesthesia monitoring with the electroencephalogram has become widely used in anesthesia practice. Generally, the methods presented are based on the spectral changes of the electroencephalogram. In this study, the authors evaluate the influence of remifentanil on the relation of timely occurrence of clinical endpoints and the spectral behavior of the electroencephalogram.
Methods: Twenty-seven patients scheduled to undergo a surgical procedure were randomly assigned to three groups. Patients blindly received equal volumes of saline or remifentanil (7.5 or 30 [mu]g [middle dot] kg-1 [middle dot] h-1) 1 min before induction of anesthesia with infusion of propofol (30 mg [middle dot] kg-1 [middle dot] h-1). The occurrence of loss of counting, loss of obeying verbal command, and loss of reaction to tetanic stimulation was assessed. The electroencephalogram was recorded from electrode Fz referenced to the common average, and an iterative algorithm was applied to solve the underlying frequency progression pattern. The positions of the clinical endpoints on the pattern were analyzed.
Results: The administration of remifentanil during induction of anesthesia with propofol led to an earlier occurrence of the clinical endpoints on the frequency progression pattern. A significant difference (P < 0.05) was observed between the saline and high-dose patient groups in all three endpoints. The effect of remifentanil was proportional to the infusion rate.
Conclusions: The infusion of remifentanil during propofol anesthesia significantly modifies the mutual relations of the electroencephalographic spectral characteristics and the endpoints in a predictable and quantifiable manner. This finding suggests that the electroencephalographic phenomena and the endpoints may not be identical but rather to some extent separate manifestations of hypnotic drug effect.

Droperidol and Ondansetron-induced QT Interval Prolongation: A Clinical Drug Interaction Study.
Perioperative Medicine
Charbit, Beny M.D. ; Alvarez, Jean Claude Pharm.D., Ph.D. ; Dasque, Eric ; Abe, Emuri Pharm.D. ; Demolis, Jean Louis M.D., Ph.D. ; Funck-Brentano, Christian M.D., Ph.D. 
Anesthesiology. 109(2):206-212, August 2008.

Abstract:
Background: Droperidol and ondansetron have previously been found to prolong the QT interval in the treatment of postoperative nausea and vomiting. However, this adverse effect has never been confirmed and compared with both drugs under controlled conditions. The objective was to study the effects of droperidol and ondansetron alone or in combination on QT interval duration in healthy subjects.
Methods: Sixteen healthy volunteers, eight males and eight females, were enrolled in this prospective, double-blind, randomized, placebo-controlled study. Subjects received 1 mg droperidol, 4 mg ondansetron, 1 mg droperidol plus 4 mg ondansetron, or a placebo, intravenously in a crossover design. Fridericia-corrected QT interval (QTcF) and plasma concentrations were measured repeatedly during 10 h at each study period. The primary endpoint was the maximal placebo time-matched and baseline-subtracted QTcF prolongation ([DELTA][DELTA]QTcF).
Results: Compared with placebo, both droperidol and ondansetron significantly prolonged the QTcF interval. [DELTA][DELTA]QTcF prolongation was 25 +/- 8 ms after droperidol, significantly greater than the 17 +/- 10-ms prolongation with ondansetron (P = 0.014). The combination of droperidol and ondansetron significantly increased the mean maximal [DELTA][DELTA]QTcF by 28 +/- 10 ms. The combination induced greater QTcF prolongation compared with ondansetron alone (P = 0.001), but not with droperidol alone (P = 0.33). There was no significant pharmacokinetic interaction between droperidol and ondansetron.
Conclusions: Under controlled conditions, both droperidol and ondansetron either alone or in combination induced significant marked QTc interval prolongation. However, the combination of both drugs did not significantly increase QTc prolongation compared with that induced by droperidol alone.

Low-dose Propofol-induced Amnesia Is Not due to a Failure of Encoding: Left Inferior Prefrontal Cortex Is Still Active.
Perioperative Medicine
Veselis, Robert A. M.D. ; Pryor, Kane O. M.D. ; Reinsel, Ruth A. Ph.D. ; Mehta, Meghana M.S. ; Pan, Hong Ph.D. ; Johnson, Ray Jr Ph.D. 
Anesthesiology. 109(2):213-224, August 2008.

Abstract:
Background: Propofol may produce amnesia by affecting encoding. The hypothesis that propofol weakens encoding was tested by measuring regional cerebral blood flow during verbal encoding.
Methods: Seventeen volunteer participants (12 men; aged 30.4 +/- 6.5 yr) had regional cerebral blood flow measured using H2O15 positron emission tomography during complex and simple encoding tasks (deep vs. shallow level of processing) to identify a region of interest in the left inferior prefrontal cortex (LIPFC). The effect of either propofol (n = 6, 0.9 [mu]g/ml target concentration), placebo with a divided attention task (n = 5), or thiopental at sedative doses (n = 6, 3 [mu]g/ml) on regional cerebral blood flow activation in the LIPFC was tested. The divided attention task was expected to decrease activation in the LIPFC.
Results: Propofol did not impair encoding performance or reaction times, but impaired recognition memory of deeply encoded words 4 h later (median recognition of 35% [interquartile range, 17-54%] of words presented during propofol vs. 65% [38-91%] before drug; P < 0.05). Statistical parametric mapping analysis identified a region of interest of 6.6 cm2 in the LIPFC (T = 7.44, P = 0.014). Regional cerebral blood flow response to deep encoding was present in this region of interest in each group before drug (T > 4.41, P < 0.04). During drug infusion, only the propofol group continued to have borderline significant activation in this region (T = 4.00, P = 0.063).
Conclusions: If the amnesic effect of propofol were solely due to effects on encoding, activation in the LIPFC should be minimal. Because LIPFC activation was not totally eliminated by propofol, the amnesic action of propofol must be present in other brain regions and/or affect other memory processes.

Greater Incidence of Emergence Agitation in Children after Sevoflurane Anesthesia as Compared with Halothane: A Meta-analysis of Randomized Controlled Trials.
Perioperative Medicine
Kuratani, Norifumi M.D., Ph.D. ; Oi, Yumiko M.D. 
Anesthesiology. 109(2):225-232, August 2008.

Abstract:
Background: Sevoflurane is a popular inhalational anesthetic for general anesthesia in children. The higher incidence of emergence agitation has been suspected after sevoflurane anesthesia as compared with halothane, whereas some controlled studies showed conflicting results. In this report, the authors performed a meta-analysis of randomized controlled trials to compare the incidence of emergence agitation in children after sevoflurane or halothane anesthesia.
Methods: A comprehensive literature search was conducted to identify clinical trials that compared the incidence of emergence agitation in children anesthetized with sevoflurane versus halothane. Two reviewers independently assessed each report to meet the authors inclusion criteria and extracted data. The data from each trial were combined using the Mantel-Haenszel fixed-effect model to calculate the pooled odds ratio and 95% confidence interval. Funnel plots were used to assess publication bias. Subgroup analysis was used to clarify the effects of age, surgical procedure, pain treatment, and premedication on the incidence of emergence agitation.
Results: The authors identified 23 studies that met their inclusion criteria. Overall, 1,252 patients received sevoflurane and 1,111 had halothane. Heterogeneity of data was statistically refuted. The pooled odds ratio for all studies was 2.21, with a 95% confidence interval of 1.77-2.77 (P < 0.0001). Publication bias was not apparent in a funnel plot. All subgroup analyses showed a higher incidence of agitation after sevoflurane anesthesia.
Conclusions: This meta-analysis revealed that emergence agitation occurred more frequently with sevoflurane than with halothane anesthesia in children.

Temperature Monitoring and Perioperative Thermoregulation.
Review Articles
Sessler, Daniel I. M.D. 
Anesthesiology. 109(2):318-338, August 2008.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Ropivacaine and levobupivacaine for bilateral selective ankle block in patients undergoing hallux valgus repair
S. PALMISANI, R. ARCIONI, P. DI BENEDETTO, R. A. DE BLASI, M. MERCIERI, P. RONCONI
Acta Anaesthesiologica Scandinavica 2008; 52 (6): 841–844

Background: A selective ankle block, blocking the tibial, deep and superficial peroneal nerves, can be used successfully for great toe surgery. No comparative information is available on selective ankle block using ropivacaine and levobupivacaine.
Methods: We compared the onset time and success rate of a selective ankle block using low volumes (12 ml) of ropivacaine 10 mg/ml and levobupivacaine 7.5 mg/ml in 40 patients undergoing elective repair of bilateral hallux valgus. Each patient received an ankle block induced in one foot with ropivacaine and in the contralateral foot with levobupivacaine.
Results: The success rate was higher [90% vs. 75%, hazard ratio (95% CI) 0.39 (0.23–0.64)] and anesthesia onset time was shorter (median, 10 vs. 20 min) after ropivacaine than after levobupivacaine. In successful ankle blocks, post-operative pain was similar in the two groups.
Conclusion: In this study, ropivacaine 10 mg/ml had a shorter anesthesia onset time and a higher success rate than levobupivacaine 7.5 mg/ml for selective ankle block.

Oxycodone vs. fentanyl in the treatment of early post-operative pain after laparoscopic cholecystectomy: a randomised double-blind study
S. KOCH, P. AHLBURG, N. SPANGSBERG, B. BROCK, E. TØNNESEN, L. NIKOLAJSEN
Acta Anaesthesiologica Scandinavica 2008; 52 (6): 845–850

Background: It has been suggested that oxycodone is superior to other opioids in the treatment of visceral pain. We therefore compared the effect of intravenous (i.v.) oxycodone and i.v. fentanyl on post-operative abdominal (visceral) pain after outpatient laparoscopic cholecystectomy.
Methods: Seventy-eight patients were randomised to intra- and post-operative pain treatment with either oxycodone (n=39) or fentanyl (n=39). The patients received 10 mg oxycodone/100 μg fentanyl at the end of anaesthesia. In the post-anaesthetic care unit (PACU), 5 mg oxycodone/50 μg fentanyl was administered to patients with moderate pain [3–5 on a numeric rating scale (NRS)], and 10 mg oxycodone/100 μg fentanyl was administered to patients with severe pain (>5 on an NRS). The following measures were recorded: intensity of pain at arrival, after 30, 60 and 90 min and at discharge from the PACU; total consumption of oxycodone/fentanyl; nausea; vomiting; sedation and pressure tolerance thresholds.
Results: The median intra- and post-operative consumption of oxycodone was 15 mg (range: 10–40 mg) and the consumption of fentanyl was 200 μg (range: 100–500 μg). The intensity of abdominal pain was significantly lower in the oxycodone group at arrival (P<0.05), after 30, 60 and 90 min, and at discharge from the PACU (P<0.01). There was a strong tendency towards more side effects with oxycodone.
Conclusions: Oxycodone provided better analgesia but also more side effects, suggesting that the doses used in the present study may not be equipotent.

Low dose of lidocaine: comparison of 15 with 20 mg/ml with dextrose for spinal anesthesia in lithotomy position and ambulatory surgery
L. E. IMBELLONI, M. A. GOUVEIA, J. A. CORDEIRO
Acta Anaesthesiologica Scandinavica 2008; 52 (6): 856–861

Background: Spinal anesthesia with the local anesthetic lidocaine has come under scrutiny because it is associated with transient neurologic symptoms (TNS). Although TNS is not associated with either lidocaine concentration or dose, its incidence has never been examined with very small doses of hyperbaric spinal lidocaine in patients in the lithotomy position. We designed this study prospectively to compare the efficacy of low-dose 15 mg/ml with low-dose 20 mg/ml hyperbaric lidocaine in patients undergoing elective outpatient surgery in the lithotomy position.
Methods: A total of 100 patients were randomized to receive either 30 mg of 15 mg/ml or the same dose of 20 mg/ml hyperbaric lidocaine. Lidocaine density at 37 °C is 1.0241 g/ml for the 15 mg/ml and 1.0260 g/ml for the 20 mg/ml solution. Patients were examined for motor block, sensory block, and block duration. Patients were contacted at 24, 48 and 72 h and questioned about their perceptions of pain after the spinal anesthesia with specific questions designed to diagnose TNS.
Results: The spread of analgesia was the same with both solutions of lidocaine. Motor block was incomplete in all patients in both groups. TNS were not observed when low doses of both solutions of lidocaine with dextrose were used in these ambulatory patients in the lithotomy position.
Conclusion: Hyperbaric lidocaine results in rapid recovery from sensory block and motor blockade. It may have advantages for patients in a day-case setting. No patients complained of TNS after discharge.

Prediction of post-operative pain after a laparoscopic tubal ligation procedure
Å. RUDIN, P. WÖLNER-HANSSEN, M. HELLBOM  and M. U. WERNER
Acta Anaesthesiologica Scandinavica 2008; 52: 938 - 945

Background: Pre-operative identification of reliable predictors of post-operative pain may lead to improved pain management strategies. We investigated the correlation between pre-operative pain, psychometric variables, response to heat stimuli and post-operative pain following a laparoscopic tubal ligation procedure.
Methods: Assessments of anxiety, mood, psychological vulnerability and pre-operative pain were made before surgery using the State-Trait Anxiety Inventory (STAI), the Hospital Anxiety Depression Scale (HADS), a psychological vulnerability test and the Short-Form McGill Pain Questionnaire (SF-MPQ), respectively. Pre-operative assessments of thermal thresholds and pain response to randomized series of heat stimuli (1 s, 44–48 °C) were made with quantitative sensory testing technique. Post-operative pain intensity was evaluated daily by a visual analogue scale during rest and during standardized dynamic conditions for 10 days following surgery. Univariate and multivariate regression analyses were used to construct prediction models.
Results: Fifty-nine patients completed the study. Post-operative pain was significantly correlated with pre-operative pain (SF-MPQ), heat pain perception, psychological vulnerability, STAI and HADS. In the multiple regression model pre-operative pain and heat pain perception were significant predictive factors (R=0.537–0.609).
Conclusion: The study indicates that pre-surgical pain and heat pain sensitivity are important pre-operative indicators of post-operative pain intensity, while psychological factors like vulnerability and anxiety seem to contribute to a lesser degree after laparoscopic tubal ligation. The prediction model accounted for 29–43% of the total variance in post-operative movement-related pain.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Influence of the anaesthetic depth on the inhibition of the oculocardiac reflex during sevoflurane anaesthesia for paediatric strabismus surgery
C. Yi and D. Jee
British Journal of Anaesthesia 2008 101(2):234-238

Background: It remains controversial whether the anaesthetic depth as assessed by bispectral index (BIS) influences the oculocardiac reflex (OCR) during strabismus surgery. We investigated whether BIS-guided sevoflurane titration may help to optimize the anaesthetic depth for inhibition of the OCR during paediatric strabismus surgery.
Methods: Eighty-four patients (aged 2–12 yr) undergoing strabismus surgery were randomly allocated to one of the three groups (n=28 for each) according to target BIS value of 40, 50, and 60. The end-tidal sevoflurane concentration with 50% N2O/O2 was adjusted towards target BIS. The incidence of OCR and the lowest heart rate (HR) were recorded in relation to the end-tidal sevoflurane concentration.
Results: The incidence of OCR was higher in Group BIS-60 (71.4%) than in Groups BIS-40 (10.7%) (P<0.001) or BIS-50 (32.1%) (P=0.003), with no difference between Group BIS-40 and Group BIS-50. The lowest HR [beats min–1, mean (SD)] during traction on the extraocular muscle was lower in Group BIS-60 [112.3 (SD 17.8)] compared with Group BIS-40 [129.3 (11.2)] (P<0.001), with no difference between BIS-40 and BIS-50 [121.4 (16.3)], and between BIS-50 and BIS-60. The end-tidal sevoflurane concentration was different between the three groups (P=0.001).
Conclusions: We confirmed that OCR is relevant to the depth of anaesthesia. BIS values of 40–50 seem adequate for the inhibition of OCR. The results suggest that BIS may be a valuable tool during sevoflurane anaesthesia for strabismus surgery in children.

Propofol-based sedation regimen for infants and children undergoing ambulatory magnetic resonance imaging
A.-M. Machata, H. Willschke, B. Kabon, S. C. Kettner and P. Marhofer
British Journal of Anaesthesia 2008 101(2):239-243

Background: Propofol is widely used for infants and children requiring sedation for magnetic resonance imaging. However, increased doses of propofol may quickly lead to an unintended deep sedation and respiratory depression. Thus, an appropriate low dosage, which nevertheless ensures sufficient sleep for successful magnetic resonance imaging (MRI) completion, would probably minimize respiratory adverse events. We investigated the safety and efficacy of a low-dose propofol-based sedation regimen in a broad age range of children.
Methods: We investigated 500 infants and children, prospectively. Premedication consisted of i.v. midazolam 0.1 mg kg–1. Sedation was induced with i.v. nalbuphine 0.1 mg kg–1 and propofol 1 mg kg–1, and maintained with propofol 5 mg kg–1 h–1. Outcome measures were induction time, sedation time, recovery time, need for additional sedation, respiratory events, cardiovascular events, paradoxical reactions, and sedation failure.
Results: Data were obtained from 53 infants and 447 children. Median (IQR) age was 5.3 (4.5, 6.1) yr and body weight was 19.3 (16.5, 24.7) kg. The induction time was 2 (1, 2) min, sedation time 55 (45, 65) min, and recovery time 8 (8, 9) min. Additional sedation was necessary in 11 patients (2.2%), mild respiratory events occurred in five patients (1%). All MRI examinations could be completed without paradoxical reaction or sedation failure.
Conclusion: This sedation regimen provides the shortest induction time so far described, a rare demand for additional sedation, a low incidence of respiratory events, and a rapid recovery.

Acupuncture and related techniques for postoperative pain: a systematic review of randomized controlled trials
Y. Sun, T. J. Gan, J. W. Dubose and A. S. Habib
British Journal of Anaesthesia 2008 101(2):151-160

Postoperative pain management remains a significant challenge for all healthcare providers. The objective of this systematic review was to quantitatively evaluate the efficacy of acupuncture and related techniques as adjunct analgesics for acute postoperative pain management. We searched the databases of Medline (1966–2007), CINAHL, The Cochrane Central Register of Controlled Trials (2006), and Scopus for randomized controlled trials (RCTs) using acupuncture for postoperative pain management. We extracted data about postoperative opioid consumption, postoperative pain intensity, and opioid-related side-effects. Combined data were analysed using a random effects model. Fifteen RCTs comparing acupuncture with sham control in the management of acute postoperative pain were included. Weighted mean difference for cumulative opioid analgesic consumption was –3.14 mg (95% confidence interval, CI: –5.15, –1.14), –8.33 mg (95% CI: –11.06, –5.61), and –9.14 mg (95% CI: –16.07, –2.22) at 8, 24, and 72 h, respectively. Postoperative pain intensity (visual analogue scale, 0–100 mm) was also significantly decreased in the acupuncture group at 8 and 72 h compared with the control group. The acupuncture treatment group was associated with a lower incidence of opioid-related side-effects such as nausea (relative risk, RR: 0.67; 95% CI: 0.53, 0.86), dizziness (RR: 0.65; 95% CI: 0.52, 0.81), sedation (RR: 0.78; 95% CI: 0.61, 0.99), pruritus (RR: 0.75; 95% CI: 0.59, 0.96), and urinary retention (RR: 0.29; 95% CI: 0.12, 0.74). Perioperative acupuncture may be a useful adjunct for acute postoperative pain management.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Evolution of ultrasound guided axillary brachial plexus blockade: retrospective analysis of 662 blocks
Nick Lo, MD, Richard Brull, MD FRCPC, Anahi Perlas, MD FRCPC, Vincent W.S. Chan, MD FRCPC, Colin J.L. McCartney, MBChB FRCA FCARCSI FRCPC, Raffaele Sacco and Hossam El-Beheiry, MBBCh PhD FRCPC
Canadian Journal of Anesthesia 55:408-413 (2008)

Purpose: Ultrasound (US) is being used increasingly to guide needle placement during axillary brachial plexus blockade (AXB). This retrospective study investigated whether US guidance can increase the success rate, decrease block onset time, and reduce local anesthetic (LA) volume for AXB compared to a traditional (TRAD) approach, namely, peripheral nerve stimulation (PNS) and transarterial (TA) techniques.
Methods: The anesthetic records, operative reports, discharge summaries, and surgical consultation notes of all patients who had undergone AXB for surgical anesthesia at the Toronto Western Hospital, between October 2003 and November 2006 were, retrospectively reviewed for evidence of block success and associated complications. Block success was defined as the achievement of surgical anesthesia without additional LA supplementation.
Results: Among the 662 patients, 535 patients underwent AXB using US guidance (US group), and 127 using TRAD techniques (TRAD group), namely, 56 using PNS (PNS subgroup) and 71 using the TA technique (TA subgroup). The block success rate was higher in the US group compared to the TRAD group (91.6% vs 81.9%, P = 0.003). The LA volume used for AXB was less in the US group compared to the TRAD group (39.8 ± 6.4 mL vs 46.7 ± 17.1 mL, P < 0.0001). Ultrasound group patients spent less time in the block procedure room than those in the TRAD group (30.6 ± 14.2 min vs 40.1 ± 27.3 min, P < 0.0001). When analyzed by subgroup, the US group demonstrated significantly greater success and shorter duration in the block room compared to the PNS subgroup, but not the TA subgroup. Complications (inadvertent intravenous LA injection, and transient neuropathy) were lower in the US group compared to the TRAD group (0.37% vs 3.15%, P = 0.014).
Conclusions: Our results suggest that US-guided AXB may improve block success, reduce the local anesthetic volume used, and shorten the time spent in the block room compared to traditional nerve localization techniques.

Case report: Treatment of rocuronium-induced anaphylactic shock with vasopressin
Li Meng, MD MPH and E. Lynne Williams, MD
Canadian Journal of Anesthesia 55:437-440 (2008)

Purpose: To report the use of vasopressin to treat a patient who, after failing to respond to volume expansion and epinephrine administration, experienced an anaphylactic reaction to rocuronium.
Clinical features: A 17-yr-old female was scheduled to undergo transnasal, transsphenoidal resection of a pituitary tumour. Shortly after induction of general anesthesia, for which rocuronium 50 mg iv was administered to facilitate tracheal intubation, the patient developed severe hypotension and diffuse erythema. This severe,allergic response was refractory to the administration of intravenous fluids, epinephrine, and phenylephrine. However, arginine vasopressin, administered intravenously as a bolus of two units, followed by an infusion of 2 U·hr–1, rapidly corrected the hemodynamic instability. Her recovery from this episode was uneventful, but surgery was cancelled. Skin testing, performed six weeks later, was positive for rocuronium and negative for cisatracurium and latex, as well as all other medications administered. Eight weeks later, the surgical procedure was performed, uneventfully, using cisatracurium as the muscle relaxant.
Conclusions: Vasopressin may be effective in the resuscitation of anesthetized patients, with hemodynamic instability associated with anaphylaxis resistant to epinephrine and alpha-agonists.

Effects of baricity of 0.5% or 0.75% levobupivacaine on the onset time of spinal anesthesia: a randomized trial
Giorgio Danelli, MD, Marco Baciarello, MD, Simone Di Cianni, MD, Michele Zasa, MD, Giuliana De Marco, MD, Simonetta Adamanti, MD and Guido Fanelli, MD
Canadian Journal of Anesthesia 55:501-506 (2008)

Purpose: Levobupivacaine has been extensively evaluated for spinal anesthesia. Its pharmacologic properties are similar to those of bupivacaine, but differences in density between two commercially-available preparations of plain levobupivacaine might lead to different block profiles. We examined the characteristics of spinal anesthesia using the same dose of 0.5% and 0.75% plain levobupivacaine.
Methods: In this randomized, controlled, double-blind clinical trial, 60 ASA I–III patients, scheduled for hip fracture surgery, were randomly allocated to receive spinal anesthesia with 15 mg of either 0.5% (group Levo-0.5), or 0.75% (group Levo-0.75) plain levobupivacaine. Onset time (primary outcome), sensory block height level by pinprick, motor block using a modified Bromage scale, and hemodynamic variables were recorded.
Results: In group Levo-0.5 (n = 29), surgical anesthesia was obtained within 15 (10–20) min, compared to 12 (7–21) min in group Levo-0.75 (n = 31) (p = 0.409). The highest sensory block level was T11 (T6–T12) in group Levo-0.5, and T10 (T8 – T12) in group Levo-0.75 (p = 0.759). Mean duration of anesthesia was 285 (224–303) min in group Levo-0.5, and 318 (243–375) min in group Levo-0.75 (p = 0.117). The groups were similar in regards to the number of failed blocks requiring general anesthesia, and the number of patients requiring vasopressors.
Conclusions: In this population of elderly patients, spinal anesthesia with 15 mg of either 0.5% or 0.75% plain levobupiva-caine resulted in similar onset of pharmacological actions, and outcomes. Potential differences in baricity did not appear to be clinically relevant in this setting.

PUB MED - TOP

Obesity as a risk factor for unanticipated admissions after ambulatory surgery.
Hofer RE, Kai T, Decker PA, Warner DO.
Mayo Clin Proc. 2008 Aug;83(8):908-16.

OBJECTIVE: To test the hypothesis that obesity is an independent risk factor for unplanned hospital admission or readmission among patients scheduled for ambulatory surgery in a tertiary medical center.
PATIENTS AND METHODS: Existing databases were used to identify 235 obese patients (body mass index [BMI] >40) scheduled for ambulatory surgery from January 2, 2002, through December 31, 2003, at Mayo Clinic's site in Rochester, MN. Each patient was matched to a normal-weight control (BMI <25) by age, sex, surgical procedure, type of anesthesia, and date of surgery, and the medical records of all patients were reviewed. Conditional logistic regression analysis was performed to assess whether obesity is an independent risk factor for unplanned postoperative hospital admission. In all cases, 2-sided tests were performed. P<.05 was considered statistically significant.
RESULTS: Obese patients (mean +/- SD BMI, 44+/-4) were matched with control patients (mean +/- SD BMI, 23+/-2). Comorbidity was more frequent in the obese cohort. The frequency of unplanned hospital admission did not differ between groups: 61 obese patients (26.0%) and 52 control patients (22.1%) were admitted (odds ratio, 1.3; 95% confidence interval, 0.8-2.0; P=.30).
CONCLUSION: Obesity is not a significant independent risk factor for unplanned admission after ambulatory surgery, suggesting that obesity per se should not prevent ambulatory surgery from being scheduled.

Anesthesia outside the operating room in the office-based setting.
Perrott DH.
Curr Opin Anaesthesiol. 2008 Aug;21(4):480-5.

PURPOSE OF REVIEW: The majority of anesthesia services provided outside the operating room or ambulatory surgery center is in the office-based setting. This review will focus on three areas that are critical to office-based anesthesia: safety, quality of care and patient satisfaction.
RECENT FINDINGS: Data obtained from the State of Florida office-based surgery adverse event data repository indicate that, even with The American Society of Anesthesiology I patients, there remains opportunity to improve outcomes. Careful patient selection remains critical, especially the patient with a history of sleep apnea. While general anesthesia remains the gold standard, expanded use of local anesthesia, regional blocks and variation on sedation techniques offer alternatives that may reduce risks but still maintain a high quality of care. While there is limited office-based anesthesia satisfaction data, limiting postoperative nausea and vomiting remains a major patient satisfier of which an occurrence rate of zero may be possible.
SUMMARY: There is rapid growth for the need of safe and high quality office-based anesthesia. To meet these needs, a special set of skills is required, which may require expanded exposure and experience during training. An office-based anesthesia central data repository is needed for benchmarking and identifying areas for improvement. Finally, with advances in surgical technology, there is a need for focused research in office-based anesthetic techniques and modalities and patient satisfaction.

The duration of intrathecal bupivacaine mixed with lidocaine.
Lee SJ, Bai SJ, Lee JS, Kim WO, Shin S, Lee KY.
Anesth Analg. 2008 Sep;107(3):824-7.

BACKGROUND: Although spinal bupivacaine may have too long duration to be useful in the ambulatory setting, recent animal data suggest that lidocaine added to spinal bupivacaine may reduce the duration of bupivacaine spinal anesthesia. We explored whether lidocaine added to spinal bupivacaine could shorten the duration of bupivacaine spinal anesthesia in humans similarly to what has been reported in animals.
METHODS: Ninety patients presenting for transurethral resection of bladder tumor or prostate were assigned to one of three groups by double blind randomization to receive intrathecal 1.5 mL of hyperbaric 0.5% bupivacaine, plus 0.6 mL of one of three solutions: saline (Group I, n = 30, control), 1% lidocaine (Group II, n = 30), and 2% lidocaine (Group III, n = 30). Peak sensory block level, time to peak sensory block, times to two-segment, L1, and S2 regressions from peak sensory block, motor blocks at peak sensory block, L1, and S2 regressions, and postanesthesia care unit stay time (PACU time) were measured.
RESULTS: Times to peak sensory block were similar in all three groups. Times to two-segment, L1, and S2 regressions from peak sensory block, and PACU time were significantly reduced in Group II compared to Group I. Times to L1, S2 regressions, and PACU times in Group III were significantly prolonged.
CONCLUSIONS: We conclude that lidocaine (6 mg) mixed to spinal bupivacaine (7.5 mg) can shorten the duration of bupivacaine spinal anesthesia, therefore provide more rapid recovery from the spinal anesthesia compared to the same dose of bupivacaine (7.5 mg) alone.

The optimum bolus dose of remifentanil to facilitate laryngeal mask airway insertion with a single standard dose of propofol at induction in children.
Kwak HJ, Kim JY, Kim YB, Chae YJ, Kim JY.
Anaesthesia. 2008 Sep;63(9):954-8. Epub 2008 Jun 28.

The purpose of this study was to determine the optimal bolus dose of remifentanil required for the successful insertion of the laryngeal mask airway during propofol induction in children without a neuromuscular blocking agent. Twenty-six paediatric patients, aged 3-10 years, requiring anaesthesia for short ambulatory surgery were recruited. A predetermined bolus dose of remifentanil was injected over 30 s, followed by propofol 2.5 mg.kg(-1) over 10 s. The bolus dose of remifentanil was determined by a modified Dixon's up-and-down method, starting from 0.5 microg.kg(-1) (0.1 microg.kg(-1) as a step size). Laryngeal mask insertion was attempted 90 s after the end of remifentanil injection and the response of patients was classified as either 'movement' or 'no movement'. The bolus dose of remifentanil at which there was a 50% probability of successful laryngeal mask insertion (ED(50)) during induction with 2.5 mg.kg(-1) propofol was 0.56 (0.07) microg.kg(-1) in children without a neuromuscular blocking agent. From probit analysis, the ED(50) and ED(95) of remifentanil were 0.52 microg.kg(-1) (95% confidence limits, 0.42-0.62 microg.kg(-1)) and 0.71 microg.kg(-1) (95% confidence limits, 0.61-1.40 microg.kg(-1)), respectively.

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