Inspired Oxygen Fraction of 0.8 Does Not Attenuate Postoperative Nausea and Vomiting after Strabismus Surgery.
Treschan, Tanja A. M.D. ; Zimmer, Christian M.D. ; Nass, Christoph M.D. ; Stegen, Bernd M.D. ; Esser, Joachim M.D. ; Peters, Jurgen M.D. 
Anesthesiology. 103(1):6-10, July 2005

Background: Postoperative nausea and vomiting (PONV) is a distressing problem after strabismus surgery. An inspired oxygen fraction has been reported to decrease PONV in patients after colon resection and to be more effective than ondansetron after gynecologic laparoscopy. Therefore, in a randomized, prospective, placebo-controlled study, the authors tested whether an inspired oxygen fraction of 0.8 decreases PONV in patients undergoing strabismus surgery and whether oxygen is more effective than ondansetron.
Methods: With approval of the authors' institutional review board, 210 patients were randomly assigned to receive one of three treatments: (1) 30% inspired oxygen in air plus intravenous administration of saline, (2) 80% inspired oxygen in air plus intravenous administration of saline, or (3) 30% inspired oxygen in air plus 75 [mu]g/kg ondansetron intravenously during induction. General anesthesia was standardized and included etomidate, alfentanil, and mivacurium for induction and sevoflurane for maintenance. PONV was evaluated 6 and 24 h postoperatively by an investigator unaware of treatment assignment.
Results: Overall postoperative incidence of nausea and vomiting was 41% for inspired oxygen fraction of 0.3 plus placebo, 38% for inspired oxygen fraction of 0.8 plus placebo, and 28% for inspired oxygen fraction of 0.3 plus ondansetron, respectively (P = 0.279). Therefore, there was no statistically significant difference of PONV incidence among groups.
Conclusions: An inspired oxygen fraction of 0.8 during general anesthesia with sevoflurane does not decrease PONV in patients undergoing strabismus repair. Ondansetron also did not significantly decrease PONV in our study setting.

Management of the Difficult Airway: A Closed Claims Analysis.
Peterson, Gene N. M.D., Ph.D. ; Domino, Karen B. M.D., M.P.H. ; Caplan, Robert A. M.D. ; Posner, Karen L. Ph.D. ; Lee, Lorri A. M.D. ; Cheney, Frederick W. M.D. 
Anesthesiology. 103(1):33-39, July 2005

Background: The purpose of this study was to identify the patterns of liability associated with malpractice claims arising from management of the difficult airway.
Methods: Using the American Society of Anesthesiologists Closed Claims database, the authors examined 179 claims for difficult airway management between 1985 and 1999 where a supplemental data collection tool was used and focused on airway management, outcomes, and the role of the 1993 Difficult Airway Guidelines in litigation. Chi-square tests and multiple logistic regression analysis compared risk factors for death or brain damage (death/BD) from two time periods: 1985-1992 and 1993-1999.
Results: Difficult airway claims arose throughout the perioperative period: 67% upon induction, 15% during surgery, 12% at extubation, and 5% during recovery. Death/BD with induction of anesthesia decreased in 1993-1999 (35%) compared with 1985-1992 (62%; P < 0.05; odds ratio, 0.26; 95% confidence interval, 0.11-0.63; P = 0.003). In contrast, death/BD associated with other phases of anesthesia did not significantly change over the time periods. The odds of death/BD were increased by the development of an airway emergency (odds ratio, 14.98; 95% confidence interval, 6.37-35.27; P < 0.001). During airway emergencies, persistent intubation attempts were associated with death/BD (P < 0.05). Since 1993, the Airway Guidelines were used to defend care (8%) and criticize care (3%).
Conclusions: Death/BD in claims from difficult airway management associated with induction of anesthesia but not other phases of anesthesia decreased in 1993-1999 compared with 1985-1992. Development of additional management strategies for difficult airways encountered during maintenance, emergence, or recovery from anesthesia may improve patient safety.

Primer of Postoperative Pruritus for Anesthesiologists.
Waxler, Beverly M.D. ; Dadabhoy, Zerin P. M.D. ; Stojiljkovic, Ljuba M.D., Ph.D. ; Rabito, Sara F. M.D., F.A.H.A.
Anesthesiology. 103(1):168-178, July 2005

Postoperative itching is an important problem in the postoperative care unit. Pruritus after surgery may be drug induced (including intrathecal opioids) or secondary to a preexisting systemic disease. Mechanisms of itching are complex and not completely understood. The purpose of this review is to highlight new discoveries in pathways and mechanisms of pruritus and to summarize up-to-date knowledge about treatment of itching after surgery. More basic and clinical studies are needed to address the effects of drugs on specific receptors and improve the treatment of postoperative pruritus.

Sex- and Age-related Differences in Morphine Requirements for Postoperative Pain Relief.
Aubrun, Frederic M.D.; Salvi, Nadege M.D. ; Coriat, Pierre M.D. ; Riou, Bruno M.D., Ph.D. 
Anesthesiology. 103(1):156-160, July 2005

Background: Sex-related differences in the perception of pain and susceptibility to opioids remain a matter of debate. Intravenous morphine titration used to obtain pain relief in the immediate postoperative period is a unique clinical model for assessing the effect of sex on reported pain. Because of the wide variation in dose requirements for pain management, the authors conducted a prospective study in a large population and also assessed the effect of aging.
Methods: Intravenous morphine titration was administered as a bolus of 2 (body weight << 60 kg) or 3 mg (body weight > 60 kg) during the immediate postoperative period. The interval between each bolus was 5 min. The visual analog pain scale (VAS) threshold required to administer morphine was 30, and pain relief was defined as a VAS score of 30 or less. Data are expressed as mean +/- SD.
Results: Data from 4,317 patients were analyzed; 54% of the patients were male, and 46% were female. The mean morphine dose required to obtain pain relief was 11.9 +/- 6.8 mg or 0.173 +/- 0.103 mg/kg. Women had a higher initial VAS score (74 +/- 19 vs. 71 +/- 19; P < 0.001) and required a greater dose of morphine (0.183 +/- 0.111 vs. 0.165 +/- 0.095 mg/kg; P < 0.001). In contrast, no significant difference was noted in elderly (aged > 75 yr) patients (0.163 +/- 0.083 vs. 0.157 +/- 0.085 mg/kg).
Conclusion: Women experienced more severe postoperative pain and required a greater dose (+11%) of morphine than men in the immediate postoperative period. This sex-related difference disappeared in elderly patients.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Team communication in the operating room
J. M. Davies
Volume 49 Issue 7 Page 898 - August 2005

Good communication is vital for safe patient care and good team functioning, not only in the Operating Room but also in all areas of healthcare, as well as in other safety critical industries. Examples from aviation demonstrate both the failures and the successes that can arise from poor and excellentcommunication. There are six components of effective teamwork: situational awareness, problem identification, decision making, workload distribution, time management and conflict resolution. Practising these, and self-evaluation of team communication, should help to improve team function and contribute to making patient care safer.

Future of regional anaesthesia
P. H. Rosenberg
Volume 49 Issue 7 Page 913 - August 2005

The development and refinement of regional anaesthetic techniques for various types of surgery, mainly obstetric, ophthalmic and orthopaedic surgery, and of continuous regional analgesia continues. Suitable analgesic drug mixtures, and concentrations, will be further tested in order to find the ideal analgesic regimen for each type of surgery and for the individual patient. No new local anaesthetics or equipment for clinical use are expected in the near future. Improvement therefore depends much on how the anaesthesiologists use the present drugs, needles, nerve detection devices, catheters and pumps. During training in regional anaesthesia for the speciality of anaesthesiology and intensive care medicine, it may suffice to concentrate only on certain common techniques such as epidural block, spinal block, axillary brachial plexus block, intravenous regional anaesthesia and femoral nerve block. Rare regional anaesthetic blocks and invasive techniques should be mastered and taught by specially trained regional anaesthesiology experts. In chronic pain, regional anaesthetic blocks with local anesthetics are not expected to play any major therapeutic role. However, nerve blocks can be useful for diagnostic purposes and in order to facilitate rehabilitation in chronic pain syndromes.

Factorial design provides evidence to guide practice of anaesthesia
K. Korttila and C. C. Apfel
Volume 49 Issue 7 Page 927 - August 2005

Many scientific articles are written merely to get something published, neglecting the clinician who would like the medical literature to guide their practice. Evidence-based medicine is expected to help in clinical decision-making. Systematic reviews of the literature followed by a meta-analysis of randomized, controlled trials (RCT) have claimed to represent the highest strength of evidence. However, the results published in meta-analyses have not always been confirmed in subsequent large RCTs. An analysis of 12 large RCTs and 19 meta-analyses addressing the same questions found that the outcomes of these large RCTs were not predicted accurately 35% of the time by previously published meta-analyses. Therefore, meta-analyses of several small RCTs do not obviate the need for large, multicentre RCTs, which can still be considered as a gold standard for the development of clinical guidelines or practice plans. Moreover, large RCTs using a factorial design can be highly efficient because they can answer several clinical questions at the same time and offer the only systematic approach to investigate an interaction of combinations in multimodal approaches.

Infraclavicular block causes less discomfort than axillary block in ambulatory patients
Z. J. Koscielniak-Nielsen, H. Rasmussen, L. Hesselbjerg, T P. Nielsen and Y. Gürkan
Volume 49 Issue 7 Page 1030 - August 2005

Background: This randomized study was designed to compare discomfort caused by axillary or infraclavicular blocks in ambulatory patients. We identified which of the three block components, needle passes, local anesthetic (LA) injections, and electrical stimulations, is most painful and quantified pain intensity on a visual analog scale (VAS 0-100). We also assessed onset and quality of analgesia, adverse events and patients' acceptance.
Methods: Eighty patients were studied. In axillary group -A, four LA injections were made after stimulating median, musculocutaneous, ulnar and radial nerves. In infraclavicular group -I, the whole LA volume was injected after stimulating median or ulnar or radial nerves. Patients were ready for surgery when they had analgesia/anesthesia distal to the elbow.
Results: Median intensity of block discomfort was 22 in A group and 10 in I group (P < 0.01). There was no difference in distribution of the most painful block components between the groups. Block performance times were 4 min in I group and 7 min in A group (P < 0.01). Block onset times were 18 min in A group and 20 min in I group (NS). There was one block failure in I group. Three patients in A group and five in I group required supplementary blocks (NS). Transient adverse events occurred in 14 A-group and two I-group patients (P<0.01). Thirty-seven I-group and 33 A-group patients were satisfied with the block (NS).
Conclusions: Infraclavicular block by single injection caused less discomfort and fewer adverse events than axillary block by multiple injections. Block effectiveness, onset time and patients' acceptance were similar.

Comparison of two different techniques for brachial plexus block: infraclavicular versus axillary technique
Z. Ertug, A. Yegin, S. Ertem, N. Sahin, N. Hadimioglu, L. DösemecI and M. Erman
Volume 49 Issue 7 Page 1035 - August 2005

Background: Brachial plexus block via the axillary approach is problematic in patients with limited arm mobility. In such cases, the infraclavicular approach may be a valuable alternative. The purpose of our study was to compare axillary and infraclavicular techniques for brachial plexus block in patients undergoing arm or forearm surgery.
Methods: After institutional approval and informed consent were obtained, 30 patients (ASA physical status I or II) scheduled for forearm and hand surgery under brachial plexus anesthesia were included in the study. Patients were randomly allocated into two groups. Brachial plexus block was performed via the axillary approach in the Group A patients and via the infraclavicular approach in the Group I patients using a peripheral nerve stimulator. All blocks were performed with a total dose of 40 ml 0.375% bupivacaine.
Results: In each nerve territory (radial, ulnar, median, and musculocutaneous), the mean values of the degree and the duration of the sensory block and motor block were not significantly different between the two groups (P > 0.05). Inadvertent vessel puncture was significantly more frequent in the axillary approach (P < 0.05).
Conclusion: Brachial plexus block performed via the infraclavicular approach is as safe and effective as the axillary approach. Infraclavicular approach may be preferred to the axillary approach when the upper arm mobility is impaired or not desired.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Recent advances in the non-pharmacological management of postoperative nausea and vomiting (REVIEW)
D. J. Rowbotham
British Journal of Anaesthesia 2005 95(1):77-81

No abstract available.

Injuries associated with anaesthesia. A global perspective (REVIEW)
A. R. Aitkenhead
British Journal of Anaesthesia 2005 95(1):95-109

No abstract available.

Efficacy of prophylactic ketamine in preventing postoperative shivering
D. Dal, A. Kose, M. Honca, S. B. Akinci, E. Basgul and U. Aypar
British Journal of Anaesthesia 2005 95(2):189-192

Background. Treatment with ketamine and pethidine is effective in postoperative shivering. The aim of this study was to compare the efficacy of low-dose prophylactic ketamine with that of pethidine or placebo in preventing postoperative shivering.
Methods. A prospective randomized double-blind study involved 90 ASA I and II patients undergoing general anaesthesia. Patients were randomly allocated to receive normal saline (Group S, n=30), pethidine 20 mg (Group P, n=30) or ketamine 0.5 mg kg^-1 (Group K, n=30) intravenously 20 min before completion of surgery. The anaesthesia was induced with propofol 2 mg kg^-1, fentanyl 1 µg kg^-1 and vecuronium 0.1 mg kg^-1. It was maintained with sevoflurane 2–4% and nitrous oxide 60% in oxygen. Tympanic temperature was measured immediately after induction of anaesthesia, 30 min after induction and before administration of the study drug. An investigator, blinded to the treatment group, graded postoperative shivering using a four-point scale and postoperative pain using a visual analogue scale (VAS) ranging between 0 and 10.
Results. The three groups did not differ significantly regarding patient characteristics. The number of patients shivering on arrival in the recovery room, and at 10 and 20 min after operation were significantly less in Groups P and K than in Group S. The time to first analgesic requirement in Group S was shorter than in either Group K or Group P (P<0.005). There was no difference between the three groups regarding VAS pain scores.
Conclusion. Prophylactic low-dose ketamine was found to be effective in preventing postoperative shivering.

Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children
H. Willschke, P. Marhofer, A. Bösenberg, S. Johnston, O. Wanzel, S. G. Cox, C. Sitzwohl and S. Kapral
Br. J. Anaesth. 95: 226-230 

Background. The ilioinguinal/iliohypogastric nerve block is a popular regional anaesthetic technique for children undergoing inguinal surgery. The success rate is only 70–80% and complications may occur. A prospective randomized double-blinded study was designed to compare the use of ultrasonography with the conventional ilioinguinal/iliohypogastric nerve block technique.
Methods. One hundred children (age range, 1 month–8 years) scheduled for inguinal hernia repair, orchidopexy or hydrocele repair were included in the study. Following induction of general anaesthesia, the children received an ilioinguinal/iliohypogastric block performed either under ultrasound guidance using levobupivacaine 0.25% until both nerves were surrounded by the local anaesthetic or by the conventional ‘fascial click’ method using levobupivacaine 0.25% (0.3 ml kg^-1). Additional intra- and postoperative analgesic requirements were recorded.
Results. Ultrasonographic visualization of the ilioinguinal/iliohypogastric nerves was possible in all cases. The amount of local anaesthetic used in the ultrasound group was significantly lower than in the ‘fascial click’ group (0.19 (SD 0.05) ml kg^-1 vs 0.3 ml kg^-1, P<0.0001). During the intraoperative period 4% of the children in the ultrasound group received additional analgesics compared with 26% in the fascial click group (P=0.004). Only three children (6%) in the ultrasound-guided group needed postoperative rectal acetaminophen compared with 20 children (40%) in the fascial click group (P<0.0001).
Conclusions. Ultrasound-guided ilioinguinal/iliohypogastric nerve blocks can be achieved with significantly smaller volumes of local anaesthetics. The intra- and postoperative requirements for additional analgesia are significantly lower than with the conventional method.

CANADIAN JOURNAL OF ANESTHESIA - TOP

The value of screening preoperative chest x-rays: a systematic review
Hwan S. Joo, MD FRCPC, Jean Wong, MD FRCPC, Viren N. Naik, MD Med FRCPC and Georges L. Savoldelli, MD
Canadian Journal of Anesthesia 52:568-574 (2005)

Purpose: Chest x-ray (CXR) is the most frequently ordered radiological test in Canada. Despite published guidelines, variable policies exist amongst different hospitals for ordering of preoperative CXRs. The purpose of this study was to systematically review the literature on the value of screening CXRs and establish evidence to support guidelines for the use of preoperative screening CXRs.
Source: Medline and Embase were searched under set terms for all English language articles published during 1966–2004. All eligible studies were reviewed and data were extracted individually by two authors. Of the 513 articles identified, 14 studies met both inclusion and exclusion criteria.
Principal findings: The quality of published evidence was modest as only six of the studies were rated as fair and eight as poor. Of the reported studies, diagnostic yield increased with age. However, most of the abnormalities consisted of chronic disorders such as cardiomegaly and chronic obstructive pulmonary disease (up to 65%). The rate of subsequent investigations was highly variable (4–47%). When further investigations were performed, the proportion of patients who had a change in management was low (10% of investigated patients). Postoperative pulmonary complications were also similar between patients who had preoperative CXRs (12.8%) and patients who did not (16%).
Conclusion: An association between preoperative screening CXRs and decrease in morbidity or mortality could not be established. As the prevalence of CXR abnormalities is low in patients under the age of 70, there is fair evidence that routine CXRs should not be performed for patients in this age group without risk factors. For patients over 70, there is insufficient evidence for or against performance of routine CXRs. The current recommendation from the Guidelines Association Committee that routine CXRs should not be performed for patients over 70 without risk factors is supported by this study.

Selective ordering of preoperative investigations by anesthesiologists reduces the number and cost of tests
Barry A. Finegan, FRCPC, Saifudin Rashiq, FRCPC, Finlay A. McAlister, FRCPC and Paul O’Connor, FFARCSI
Canadian Journal of Anesthesia 52:575-580 (2005)

Purpose: Preoperative investigations are frequently ordered according to care maps or protocols. We hypothesized that selective ordering of investigations by anesthesiology staff would reduce the number and cost of testing.
Methods: Prospective descriptive double cohort study carried out over 17 weeks in a tertiary care preadmission clinic. In Group 1, testing followed usual practice (based on standing preoperative orders) while in Group 2 testing was initiated only on the order of an attending anesthesiologist or anesthesiology resident. Postoperative complications were categorized and confirmed by an internist blinded to group assignment. Fisher’s exact test, Chi-square and Student’s t test were used to compare the groups as appropriate. Statistical significance was inferred at P < 0.05.
Results: Data were obtained from 507 patients in Group 1 and 431 patients in Group 2. Demographics and ASA risk score were similar in both groups. The mean number of tests ordered did not differ between groups. The mean cost of investigations was reduced from $124 in Group 1 to $95 in Group 2 (P < 0.05). If data for patients assessed by staff anesthesiologists only were considered, the mean cost of testing was reduced to $73. The number and cost of tests ordered by anesthesia residents were similar to that in Group 1. More complications were noted in Group 2, but these did not appear to be related to the altered test ordering practice.
Conclusion: Selective test ordering by staff anesthesiologists reduces the number and cost of preoperative investigations. Educational efforts should be directed towards improving resident and staff preoperative test ordering practices.

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Use of a remifentanil and propofol combination in outpatients to facilitate rapid discharge home.
Brady WJ, Meenan DR, Shankar TR, Balon JA, Mennett DR.
AANA J. 2005 Jun;73(3):207-10.

The goal of our study was to evaluate whether the combination of remifentanil and propofol facilitated shorter recovery time and decreased charges compared with conventional balanced anesthesia. We studied 49 patients, aged 13 to 75 years, who underwent elective outpatient surgery. All data were analyzed using the Pearson chi2 and the Student t test; results were considered statistically significant at a P value of.05 or less. Group 1 received a remifentanil-propofol combination and group 2, a conventional balanced anesthetic. Group 1 had decreased mean operating room (dollar 280.83 vs dollar 337.42; P = .05) and operating room plus postanesthesia care unit (PACU) (dollar 442.67 vs dollar 544.62) charges (P = .02). Group 1 had less PACU time (48.26 vs 59.62 minutes) and 2 group 1 patients bypassed the PACU. We conclude that a remifentanil-propofol combination is more cost effective than conventional balanced anesthetics and enables some patients to bypass the PACU, resulting in quicker discharge. Our findings have important implications for ambulatory surgery centers and office-based practices.

Subanesthetic ketamine: how it alters physiology and behavior in humans.
Rowland LM.
Aviat Space Environ Med. 2005 Jul;76(7 Suppl):C52-8.

Ketamine is a drug that is commonly used for anesthesia and analgesia worldwide. Although it has an excellent safety profile, cognitive and psychotomimetic adverse effects are commonly associated with its administration. This review describes the clinical applications, potential adverse events, neurobiological, and behavioral effects of ketamine used at subanesthetic doses in humans.

Evaluation of relatively low dose of oral transmucosal ketamine premedication in children: a comparison with oral midazolam.
Horiatis T, Kawaguchi M, Kurehara K, Kawaraguchi Y, Sasaoka N, Furuya H.
Paediatr Anaesth. 2005 Aug;15(8):643-7.

Oral Transmucosal ketamine (lollipop) has been shown to be an effective, harmless preoperative medication for children. However, its efficacy was not compared with commonly used premedication drugs. We, therefore, compared the efficacy of oral transmucosal ketamine with oral midazolam for premedication in children. Methods : Fifty-five children (2-6 years of age) were randomized to receive orally either a lollipop containing 50 mg of ketamine (the group K; n = 27) or syrup containing 0.5 mg.kg(-1) of midazolam (the group M; n = 28) before minor surgery. A five points-sedation score (1 = asleep to 5 = agitated; scores 2 and 3 were defined as 'effective') on arrival in the operating room and a three points-acceptance score of separation from the parents and a three points-mask cooperation score at induction of anesthesia (1 = easy to 3 = markedly resistant; score 3 was defined as 'poor') were used. Results : Sedation scores in group K were significantly higher than those in group M (P = 0.012), and the incidence of 'effective' in sedation was significantly lower in group K than in group M (P = 0.036). The incidence of 'poor' at separation from the parents and for mask cooperation was significantly higher in group K than in group M (P = 0.017, P = 0.019, respectively). Conclusion : These results indicate that a relatively low dose of oral transmucosal ketamine premedication provides no benefits over oral midazolam in children.

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