Volume 4, Issue 11 S A M B A T A L K S - PAGE 3 April, 2005

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

Preoperative Intravenous Fluid Therapy Decreases Postoperative Nausea and Pain in High Risk Patients
C. H. Maharaj, MB, BSc, FCARCSI, S. R. Kallam, MB, FCARCSI, A. Malik, MB, FCARCSI, P. Hassett, MB, FCARCSI, D. Grady, MB, FFARCSI, and J. G. Laffey, MD, MA, BSc, FFARCSI
Anesth Analg 2005;100:675-682

The potential for preoperative IV rehydration to reduce postoperative nausea and vomiting (PONV) and pain in patients undergoing ambulatory surgery remains unclear, with conflicting results reported. We sought to determine whether preoperative IV rehydration with a balanced salt solution would decrease the incidence of PONV in patients at increased risk for these symptoms. Eighty ASA grade I–III patients presenting for gynecologic laparoscopy were randomized to receive large (2 mL/kg per hour fasting) or small (3 mL/kg) volume infusions of compound sodium lactate solution over 20 min preoperatively. A standardized balanced anesthetic was used. The incidence and severity of PONV and pain, and need for supplemental antiemetic and analgesic therapy, were assessed by a blinded investigator at 0.5, 1, and 4 h postoperatively, and on the first and third postoperative days. The incidence (control 87% versus large volume 59%) and severity of PONV were significantly reduced in the large volume infusion group at all time intervals. The large volume infusion group also had decreased postoperative pain scores and required less supplemental analgesia. Preoperative correction of intravascular volume deficits effectively reduces PONV and postoperative pain in high risk patients presenting for ambulatory surgery. We recommend the preoperative administration of 2 mL/kg of compound sodium lactate for every hour of fasting to patients with an increased PONV risk presenting for ambulatory surgery.

Bacteriostatic Saline Containing Benzyl Alcohol Decreases the Pain Associated with the Injection of Propofol
Sean C. Minogue, FCARCSI, and Deidre A. Sun, FANZCA
Anesth Analg 2005;100:683-686

Bacteriostatic saline is a physiological saline solution containing the bacteriostatic agent benzyl alcohol as a 0.9% solution. It is used mostly for diluting and dissolving drugs for IV injection and as a flush for intravascular catheters. It also has local anesthetic properties. We studied its efficacy in decreasing the pain associated with IV administration of propofol and compared it with mixing lidocaine with propofol. One-hundred-twenty patients were randomly allocated into three groups. All patients received propofol 50 mg. The benzyl alcohol group received bacteriostatic saline as a preinjection, and the lidocaine group received propofol containing lidocaine. The placebo group did not receive bacteriostatic saline or lidocaine. Fifteen of 39 patients (38%) in the benzyl alcohol group complained of pain on injection compared to 33 of 39 (84%) in the placebo group and 22 of 42 (52%) in the lidocaine group. Differences were significant between the benzyl alcohol and placebo groups (P < 0.01) and the lidocaine and placebo groups (P < 0.01). Preinjection with bacteriostatic saline decreases the incidence of pain associated with IV administration of propofol and is comparable to that of mixing lidocaine with propofol.

Awareness During Anesthesia in Children: A Prospective Cohort Study
Andrew J. Davidson, MBBS, GradDipEpiBiostats, FANZCA, Grace H. Huang, BMedSci, Caroline Czarnecki, BMedSci, Margaret A. Gibson, BN, RN, Stephanie A. Stewart, BN, RN, Kris Jamsen, BSc, PGDip(Stats), and Robyn Stargatt, PhD, MAPS
Anesth Analg 2005;100:653-661

During routine adult anesthesia, the risk of awareness is 0.1%–0.2%. No recent studies have reported the incidence in children. Altered pharmacology and differing anesthesia techniques suggest that the incidence may differ in children. In this prospective cohort study, we determined the incidence of awareness during anesthesia in children. Eight-hundred-sixty-four children aged 5–12 yr who had undergone general anesthesia at The Royal Children’s Hospital were interviewed on 3 occasions to determine the incidence of awareness. The awareness assessment was nested within a larger study of behavior change after anesthesia. Reports of suspected awareness were sent to four independent adjudicators. If they all agreed, a case was classified as true awareness. Twenty-eight reports were generated. There were 7 cases of true awareness, for an incidence of 0.8% (95% confidence interval, 0.3%–1.7%). Only one aware child received neuromuscular blockers, compared with 12% in the nonaware group. No aware child reported distress, and no substantial difference was detected in behavior disturbance between aware (20%) and nonaware (16%) children. The data provide some evidence that, like adults, children are also at risk of intraoperative awareness. Although the cause remains unclear, anesthesiologists should be alerted to the possibility of awareness in children.

Advances in Diabetic Management: Implications for Anesthesia
Zulfiqar Ahmed, MD, Charles H. Lockhart, MD, Molly Weiner, RN, and Georgiana Klingensmith, MD
Anesth Analg 2005;100:666-669

The past 20 yr have seen an explosion in advances for the management of Type I diabetes mellitus. Not only new delivery systems, such as the continuous subcutaneous insulin pump, but also better and more stable types of insulin with predictable pharmacokinetics and pharmacodynamics have been developed. An artificial pancreas is now on the horizon. This progress has had a significant impact on modern perioperative care of the diabetic patient.

Airway Reflexes Return More Rapidly After Desflurane Anesthesia Than After Sevoflurane Anesthesia
Rachel Eshima Mckay, MD, Mary Jane C. Large, RN, BSN, Michel C. Balea, MS, and Warren R. Mckay, MD
Anesth Analg 2005;100:697-700

Patients given a more soluble inhaled anesthetic usually take longer to awaken from anesthesia than do patients given a less soluble anesthetic. In the present study, we tested whether such a delay in awakening was also associated with a delay in restoration of protective airway reflexes. Patients were randomly assigned to receive desflurane (n = 31) or sevoflurane (n = 33) via a laryngeal mask airway. Demographics did not differ between groups. The average minimum alveolar anesthetic concentration fraction for both groups was 0.62, and the mean (±sd) minimum alveolar anesthetic concentration hours was 1.00 ± 0.68 for desflurane versus 0.95 ± 0.57 for sevoflurane, although more patients given sevoflurane also received regional anesthesia (17 for sevoflurane and 8 for desflurane). The time from stopping anesthetic administration to appropriate response to command was longer after sevoflurane (5.5 ± 3.1 versus 3.4 ± 1.9 min; P < 0.01). In addition, the time from first response to command to ability to swallow 20 mL of water without coughing or drooling was longer after sevoflurane. At 2 min after responding to command, all patients given desflurane were able to swallow without coughing or drooling, whereas 55% of patients given sevoflurane coughed and/or drooled (P < 0.001). At 6 min after responding to command, 18% of patients given sevoflurane still could not swallow without coughing or drooling (P < 0.05). We conclude that desflurane allows an earlier return of protective airway reflexes.

The Efficacy of Preemptive Analgesia for Acute Postoperative Pain Management: A Meta-Analysis (ACCOMPANIED BY THE EDITORIAL SHOWN BELOW)
Cliff K.-S. Ong, DDS, Philipp Lirk, MD, Robin A. Seymour, PhD, and Brian J. Jenkins, MD
Anesth Analg 2005;100:757-773

Whether preemptive analgesic interventions are more effective than conventional regimens in managing acute postoperative pain remains controversial. We systematically searched for randomized controlled trials that specifically compared preoperative analgesic interventions with similar postoperative analgesic interventions via the same route. The retrieved reports were stratified according to five types of analgesic interventions: epidural analgesia, local anesthetic wound infiltration, systemic N-methyl-d-aspartic acid (NMDA) receptor antagonists, systemic nonsteroidal antiinflammatory drugs (NSAIDs), and systemic opioids. The primary outcome measures analyzed were the pain intensity scores, supplemental analgesic consumption, and time to first analgesic consumption. Sixty-six studies with data from 3261 patients were analyzed. Data were combined by using a fixed-effect model, and the effect size index (ES) used was the standardized mean difference. When the data from all three outcome measures were combined, the ES was most pronounced for preemptive administration of epidural analgesia (ES, 0.38; 95% confidence interval [CI], 0.28–0.47), local anesthetic wound infiltration (ES, 0.29; 95% CI, 0.17–0.40), and NSAID administration (ES, 0.39; 95% CI, 0.27–0.48). Whereas preemptive epidural analgesia resulted in consistent improvements in all three outcome variables, preemptive local anesthetic wound infiltration and NSAID administration improved analgesic consumption and time to first rescue analgesic request, but not postoperative pain scores. The least proof of efficacy was found in the case of systemic NMDA antagonist (ES, 0.09; 95% CI, –0.03 to 0.22) and opioid (ES, –0.10; 95% CI, –0.26 to 0.07) administration, and the results remain equivocal.

Preemptive Analgesia at the Crossroad (EDITORIAL)
Igor Kissin
Anesth Analg 2005 100: 754-756.

No abstract available.

A Retrospective Comparison of Costs for Regional and General Anesthesia Techniques
Martin Schuster, MD, MA, André Gottschalk, MD, Jürgen Berger, PhD, and Thomas Standl, MD
Anesth Analg 2005;100:786-794

In this retrospective study, we compared the costs for three different regional anesthesia techniques with the costs of general anesthesia (GA). A total of 1587 anesthesia cases which were performed for orthopedic and trauma patients over a 1-yr period in a tertiary level, university hospital setting were analyzed. The anesthesia technique-related costs were determined calculating case-specific costs for personnel, supplies, and drugs. The techniques were compared on the basis of anesthesia costs and surgical procedure duration. As a result, we found that the costs per surgical minute largely depend on the surgical procedure duration. Based on the regression function, the cost advantage of spinal anesthesia over GA can be estimated to be 13% for a 50-min case, 9% for a 100-min case, and 5% for a 200-min case. The cost disadvantage of brachial plexus anesthesia over GA can be estimated to be 19% for a 50-min case, 8% in a 100-min case, and 1% for a 200-min case. We found no difference in costs between epidural and GA. We concluded that cost comparisons of anesthesia techniques largely depend on the surgical duration of the cases studied. Even in a teaching hospital setting, spinal anesthesia has economic advantages over GA. Especially for short cases, brachial plexus block is more expensive in this setting.

Adding Clonidine to the Induction Bolus and Postoperative Infusion During Continuous Femoral Nerve Block Delays Recovery of Motor Function After Total Knee Arthroplasty
Andrea Casati, MD, Federico Vinciguerra, MD, Gianluca Cappelleri, MD, Giorgio Aldegheri, MD, Guido Fanelli, MD, Marta Putzu, MD, and Jacques E. Chelly, MD
Anesth Analg 2005;100:866-872

We evaluated the effects of adding clonidine for continuous peripheral nerve infusions. Sixty patients undergoing total knee arthroplasty under combined single-injection sciatic block and continuous femoral infusion were randomly allocated to three groups: block induction with 0.75% ropivacaine followed by 0.2% ropivacaine (group control; n = 20); block induction with 0.75% ropivacaine and 1 µg/kg clonidine followed by 0.2% ropivacaine (group cloni-bolus; n = 20), and block induction with 0.75% ropivacaine and 1 µg/kg clonidine followed by 0.2% ropivacaine with 1 µg/mL clonidine (group cloni-infusion; n = 20). After surgery, continuous femoral infusion was provided with a patient-controlled infusion pump (basal infusion rate, 6 mL/h; incremental dose, 2 mL; lockout time, 15 min). The median (range) onset time of surgical block was 15 min (5–30 min) in group control, 10 min (5–35 min) in group cloni-bolus, and 10 min (5–30 min) in group cloni-infusion (P = 0.07). No differences were reported among groups in the degree of pain measured with the visual analog scale. The total consumption of local anesthetic solution after a 24-h infusion was 170 mL (144–220 mL) in group control, 169 mL (144–260 mL) in group cloni-bolus, and 164 mL (144–248 mL) in group cloni-infusion (P = 0.51); after the second day of infusion, total consumption was 168 mL (144–200 mL) in group control, 156 mL (144–288 mL) in group cloni-bolus, and 150 mL (144–210 mL) in group cloni-infusion (P = 0.48). Hemodynamic profiles and sedation were similar in the three groups. Motor function impairment after 48 h of infusion was observed in 27% of cloni-infusion patients but in only 6% of both the control and cloni-bolus groups (P = 0.05). We conclude that adding clonidine 1 µg/mL to local anesthetic for continuous femoral nerve block does not improve the quality of pain relief but has the potential for delaying recovery of motor function.

ANESTHESIOLOGY - TOP

Effects of Bispectral Index Monitoring on Recovery from Surgical Anesthesia in 1,580 Inpatients from an Academic Medical Center.
Pavlin, Janet D. M.D. ; Souter, Karen J. M.B., B.S., F.R.C.A. ; Hong, Jae Y. D.D.S. ; Freund, Peter R. M.D. ; Bowdle, T Andrew M.D., Ph.D. ; Bower, Jan O. R.N.
Anesthesiology. 102(3):566-573, March 2005.

Background: The purpose of this study was to determine whether monitoring Bispectral Index (BIS) would affect recovery parameters in patients undergoing inpatient surgery.
Methods: Anesthesia providers (n = 69) were randomly assigned to one of two groups, a BIS or non-BIS control group. A randomized crossover design was used, with reassignment at monthly intervals for 7 months. Duration of time in the postanesthesia care unit, time from the end of surgery to leaving the operating room, and incidence of delayed recovery (> 50 min in recovery) were compared in patients treated intraoperatively with or without BIS monitoring. Data were analyzed by analysis of variance, unpaired t test, or chi-square test as appropriate.
Results: One thousand five hundred eighty patients in an academic medical center were studied. The mean BIS in the monitored group was 47. No differences were found in recovery parameters between the BIS-monitored group and the control group when comparisons were made using all subjects or when data were analyzed within anesthetic subgroups stratified by anesthetic agent or duration of anesthesia. There were some small reductions in the intraoperative concentration of sevoflurane (but not isoflurane).
Conclusions: The use of BIS monitoring for inpatients undergoing a wide variety of surgical procedures in an academic medical center had some minor effects on intraoperative anesthetic use but had no impact on recovery parameters.

Response to Mivacurium in Patients Carrying the K Variant in the Butyrylcholinesterase Gene.
Gatke, Mona R. M.D., Ph.D. ; Viby-Mogensen, Jorgen M.D., D.M.Sc., F.R.C.A. ; Ostergaard, Doris M.D. ; Bundgaard, Jens R. Ph.D.
Anesthesiology. 102(3):503-508, March 2005

Background: Mivacurium is hydrolyzed by the butyrylcholinesterase enzyme, and patients with hereditary changes of the enzyme often have prolonged duration of action of mivacurium. In this study, the authors investigated the significance of the most commonly occurring variant, the Kalow (K) variant, established using DNA analysis, for the response to mivacurium.
Methods: A total of 58 patients carrying either the wild-type butyrylcholinesterase or different combinations of the atypical (A) variant and the K variant were included. Patients who were homozygous for the A variant were given 0.03 mg/kg mivacurium. All other patients received 0.2 mg/kg mivacurium. The neuromuscular block was measured using train-of-four nerve stimulation and mechanomyography. Genotyping was performed with complete nucleotide sequencing.
Results: Heterozygosity of the K variant prolonged the time to train-of-four 0.70 from 26.6 to 34.5 min (30%; not significant) as compared with the wild type. Heterozygosity of the K variant linked to the A variant prolonged the corresponding time from 32 to 42.7 min (33%; P = 0.03) as compared with patients who were heterozygous for solely an A allele. For eight patients who were homozygous for both the A and K variants, the time to 25% recovery was 78-89 min as compared with 44-57 min in patients who were homozygous for the A variant or had only one linked K variant.
Conclusion: The K variant prolongs the duration of action of mivacurium. The current results indicate that the effect is modest when the K variant occurs heterozygously with the wild type or the A variant but is marked in patients who are homozygous for both the A and K variants.

Comparison of the Different Approaches to Saphenous Nerve Block.
Benzon, Honorio T. M.D. ; Sharma, Sanjay M.D., M.D. ; Calimaran, Arthur M.D.
Anesthesiology. 102(3):633-638, March 2005.

Background: The authors compared the efficacy of the different approaches to saphenous nerve block.
Methods: The following approaches to saphenous nerve block were compared in 10 volunteers: perifemoral, transsartorial, block at the medial femoral condyle, below-the-knee field block, and blockade at the level of the medial malleolus. Each volunteer underwent all five blocks, and the interval between blocks was 3-7 days. The sequence of injection was randomized by Latin square design. Sensory blockade at the medial aspects of the leg and foot and the strength of the anterior thigh muscles were noted.
Results: The transsartorial, perifemoral, and below-the-knee field block approaches were more effective than block at the medial femoral condyle in providing sensory anesthesia to the medial aspect of the leg. The transsartorial approach was more effective than block at the medial femoral condyle and below-the-knee field block in providing sensory anesthesia to the medial aspect of the foot. Compared with the perifemoral approach, the transsartorial approach did not cause weakness of the hip flexors and the knee extensors. In volunteers with partial numbness in the medial aspect of the foot, supplemental block of the medial dorsal cutaneous branch of the superficial peroneal nerve resulted in complete sensory blockade.
Conclusions: Sensory blockade in the medial aspects of the leg and foot is best achieved with the transsartorial approach. In some subjects, supplementary block of the medial dorsal cutaneous branch of the superficial peroneal nerve may have to be performed to assure complete numbness of the medial aspect of the foot.

Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads.
Liem, Edwin B. M.D. ; Joiner, Teresa V. B.S.N. ; Tsueda, Kentaro M.D. ; Sessler, Daniel I. M.D. [S]
Anesthesiology. 102(3):509-514, March 2005.

Background: Anesthetic requirement in redheads is exaggerated, suggesting that redheads may be especially sensitive to pain. Therefore, the authors tested the hypotheses that women with natural red hair are more sensitive to pain and that redheads are resistant to topical and subcutaneous lidocaine.
Methods: The authors evaluated pain sensitivity in red-haired (n = 30) or dark-haired (n = 30) women by determining the electrical current perception threshold, pain perception, and maximum pain tolerance with a Neurometer CPT/C (Neurotron, Inc., Baltimore, MD). They evaluated the analogous warm and cold temperature thresholds with the TSA-II Neurosensory Analyzer (Medoc Ltd., Minneapolis, MN). Volunteers were tested with both devices at baseline and with the Neurometer after 1-h exposure to 4% liposomal lidocaine and after subcutaneous injection of 1% lidocaine. Data are presented as medians (interquartile ranges).
Results: Current perception, pain perception, and pain tolerance thresholds were similar in the red-haired and dark-haired women at 2,000, 250, and 5 Hz. In contrast, redheads were more sensitive to cold pain perception (22.6 [15.1-26.1] vs. 12.6 [0-20]°C; P = 0.004), cold pain tolerance (6.0 [0-9.7] vs. 0.0 [0.0-2.0] oC; P = 0.001), and heat pain (46.3 [45.7-47.5] vs. 47.7 [46.6-48.7]°C; P = 0.009). Subcutaneous lidocaine was significantly less effective in redheads (e.g., pain tolerance threshold at 2,000-Hz stimulation in redheads was 11.0 [8.5-16.5] vs. > 20.0 (14.5 to > 20) mA in others; P = 0.005).
Conclusion: Red hair is the phenotype for mutations of the melanocortin-1 receptor. Results indicate that redheads are more sensitive to thermal pain and are resistant to the analgesic effects of subcutaneous lidocaine. Mutations of the melanocortin-1 receptor, or a consequence thereof, thus modulate pain sensitivity.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Preoperative caudal block prevents emergence agitation in children following sevoflurane anesthesia
M. T. Aouad, G. E. Kanazi, S. M. Siddik-Sayyid, F. J. Gerges, L. B. Rizk and A. S. Baraka
Acta Anaesthesiologica Scandinavica 2005, Volume 49 Issue 3 Page 300 - 304

Background:  The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain-free procedures, pain is still regarded as a major contributing factor.
Methods: In a prospective, randomized, double-blind study, we enrolled 48 premedicated and calm 2-6-year-old children undergoing inguinal hernia repair. We assigned children to one of two groups: children assigned to the caudal group (n = 24) received a caudal block to supplement sevoflurane, while children assigned to the fentanyl group (n = 24) received a bolus injection of 1 µg  kg^-1 intravenous fentanyl before skin incision to supplement sevoflurane. In the post anesthesia care unit, all children were received by their parent, and the incidence of emergence agitation and pain scores, as well as hemodynamic changes, were compared in both groups.
Results: Forty-four children completed the study. In the fentanyl group, 59% of the children were agitated following emergence from anesthesia as compared to 4.5% in the caudal group (P < 0.001). Also, pain scores, mean values of heart rate and blood pressure as well as morphine requirement were significantly higher in the post anesthesia care unit in the fentanyl group compared to the caudal group.
Conclusion: Our results show that in children undergoing inguinal hernia repair, pain control with a preoperative caudal block as compared to intraoperative intravenous fentanyl significantly reduces the incidence of emergence agitation and pain scores following sevoflurane anesthesia.

Variability of duration of action of neuromuscular-blocking drugs in elderly patients
S. R. Arain, S. Kern, D. J. Ficke and T. J. Ebert
Acta Anaesthesiologica Scandinavica 2005, Volume 49 Issue 3 Page 312 - 315

Background:  Steroid-based, non-depolarizing neuromuscular-blocking (NMB) drugs (e.g. rocuronium, vecuronium) are characterized by organ-dependent elimination and significantly longer durations of action in elderly compared to young patients. Cisatracurium is a benzylisoquinolinium NMB drug with a duration of action not altered by ageing. The objective of the study was to determine if elderly patients had less variability in duration of action with 2 x ED95 of cisatracurium compared to equipotent doses of rocuronium or vecuronium.
Methods:  Informed consent was obtained from 66 elderly patients with normal renal and liver function. Preoperative midazolam (1 mg) was given IV. The anaesthestic induction was with 5 mg  kg^-1 thiopental and 2 µg  kg^-1 fentanyl. The patients received 0.6 mg  kg^-1 rocuronium, 0.1 mg  kg^-1 vecuronium or 0.1 mg  kg^-1 cisatracurium. Anaesthetic maintenance was with sevoflurane in oxygen/nitrous oxide. Neuromuscular-blocking duration of action was defined as the return of T1 twitch height to 25% of control. Variability was determined by subtracting the actual duration of action from the mean duration of action for each drug.
Results:  The durations of action (range, min) were: cisatracurium, 37-81; vecuronium, 35-137; and rocuronium, 33-119. The median of the variability of duration was significantly less with cisatracurium (7 min) compared to vecuronium (18 min) and rocuronium (18 min) (P < 0.05).
Conclusion:  When used with sevoflurane/N₂O, there was a two-fold greater variability of duration of neuromuscular blockade in elderly patients receiving rocuronium or vecuronium compared with cisatracurium.

Anesthetic effect of epidural anesthesia with cephalad or caudad catheterization for ankle surgery or hemorrhoidectomy
W-Y. Chou, C-J. Hsu, J-T. Cheng, L-C. Yang, C-R. Lin, Y-Y. Chia, S-W. Yu and P-H. Tan
Acta Anaesthesiologica Scandinavica 2005, Volume 49 Issue 3 Page 406 - 410

Background:  The larger size of the first sacral nerve root has been reported to be an unfavorable factor leading to sacral sparing in epidural anesthesia. Previous studies have shown that an adequate analgesic effect of the epidural block was achieved with the catheter placement in the caudal direction. In this study, the anesthetic effect of epidural anesthesia with catheter placement of a cephalic or caudad direction was compared in ankle and hemorrhoid surgery.
Methods:  Twenty-one ASA physical status I or II patients undergoing surgery for ankle fractures with epidural anesthesia were enrolled and randomized into two groups. The epidural catheter was placed either to a cephalad (AU group) or caudal (AD group) direction. Another 21 patients undergoing hemorrhoidectomy were also randomized into two groups to receive epidural anesthesia in a similar way (HU and HD groups). The onset for, duration of, and recovery time from epidural anesthesia and the incidence of analgesic request were recorded.
Results:  No significant differences were demonstrated when age, height, weight or sex were compared between the four study groups. The onset time of the block and the incidence of intrasurgical analgesic request were lower in the caudal subgroup when the ankle surgery patients were compared. Otherwise, there were no significant differences in the duration of anesthesia and time to recovery or level of anesthesia.
Conclusion:  Injection of local anesthetic solution through a caudally oriented epidural catheter produces faster onset and superior quality of anesthesia in comparison with the injection through the cephaladly oriented catheter in ankle surgery, but not hemorrhoidectomy.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Double-blind randomized controlled trial to determine extent of amnesia with midazolam given immediately before general anaesthesia
R. Bulach, P. S. Myles and M. Russnak
British Journal of Anaesthesia 2005 94(3):300-305

Background. Anterograde, but not retrograde, amnesia has been demonstrated following midazolam administration. However, there have been no studies investigating whether or not immediate retrograde amnesia can be produced with midazolam.
Methods. After ethics committee approval and consent, 40 adult patients undergoing surgery and general anaesthesia were randomly allocated to one of four groups: midazolam 2 mg, midazolam 5 mg, midazolam 10 mg or control (normal saline). Measurements were made from 12 min prior to induction of anaesthesia, and the study drug was administered 8 min prior to induction of anaesthesia. Midazolam effects were measured using visual recognition of posters, recall of specific events, bispectral index (BIS) and sedation visual analogue score.
Results. Recognition and recall rates were similar between groups up until the time of study drug administration, with no evidence of retrograde amnesia (all P>0.3). There was a dose-dependent deterioration in visual recall (P=0.002), event recollection (P<0.001), BIS (P<0.001) and sedation score (P<0.001) following i.v. midazolam when compared with control.
Conclusions. We found no evidence that i.v. midazolam 2–10 mg produces immediate retrograde amnesia. Midazolam causes anterograde amnesia in a dose-responsive manner.

The preoperative administration of ketoprofen improves analgesia after laparoscopic cholecystectomy in comparison with propacetamol or postoperative ketoprofen
G. Boccara, A. Chaumeron, Y. Pouzeratte and C. Mann
British Journal of Anaesthesia 2005 94(3):347-351

Background. Non-opioid analgesics, paracetamol and non-steroid anti-inflammatory drugs (NSAIDs) are proposed for pain relief after laparoscopy. We compared perioperative propacetamol (P) and ketoprofen (K) to provide analgesia after laparoscopic cholecystectomy.
Methods. After ethical committee approval, we included 104 ASA I–II patients, without preoperative analgesic drugs, who were scheduled to undergo laparoscopic cholecystectomy. Anaesthesia was standardized using propofol, fentanyl, atracurium, isoflurane and N₂O 50%. Ketoprofen 100 mg or propacetamol 2 g or a saline drip (a 100-ml unit of saline in 10 min) was infused blindly and randomly. Patients received either ketoprofen (group K1) or propacetamol (group P1) before induction of anaesthesia and saline after surgery, or saline before surgery and ketoprofen (group K2) or propacetamol (group P2) after surgery. Postoperative visual analogue pain scores (VAS 0–100 mm) were recorded during 24 h. If VAS was >30, a second dose (placebo, ketoprofen or propacetamol) was infused. Nalbuphine 0.2 mg kg^-1 i.v. was given as rescue analgesic if VAS was ≥ 50.
Results. Ninety-eight patients were studied. The number of patients not requiring the second analgesic was greater in K1 (33.5%) than the others ( K2 0%, P1 0%, P2 7.5%). VAS scores were significantly lower in K1 (P=0.001), with less nalbuphine consumption compared with P1. VAS and opioid request were similar in K2 and P2.
Conclusion. Preoperative administration of ketoprofen improves postoperative analgesia after laparoscopic cholecystectomy compared with its postoperative administration and pre- and postoperative propacetamol.

Randomized, double-blind, phase III, controlled trial comparing levobupivacaine 0.25%, ropivacaine 0.25% and bupivacaine 0.25% by the caudal route in children
B. Locatelli, P. Ingelmo, V. Sonzogni, A. Zanella, V. Gatti, A. Spotti, S. Di Marco and R. Fumagalli
British Journal of Anaesthesia 2005 94(3):366-371

Background. The rationale for replacing racemic bupivacaine with the s-enantiomers levobupivacaine and ropivacaine is to provide a wider margin of safety with the same analgesic efficacy and less postoperative motor block. In a randomized, double-blind, phase III, controlled trial we compared the caudal administration of levobupivacaine 0.25% and ropivacaine 0.25% with bupivacaine 0.25% in children.
Methods. Ninety-nine ASA I–II children less than 10 yr old scheduled for elective sub-umbilical surgery were randomized to receive caudal block with bupivacaine 0.25%, ropivacaine 0.25% or levobupivacaine 0.25%. The primary outcome of the study was the clinical efficacy of the caudal block during the operation. Secondary outcome measures were analgesic onset time, pain relief after the operation and residual motor blockade.
Results. The proportion of children with effective analgesia during the operation was similar among groups. There were no significant differences in the analgesic onset time of the caudal block. Bupivacaine produced a significant incidence of residual motor block compared with levobupivacaine or ropivacaine at wake-up (P<0.01). There were no significant differences in the number of patients receiving rescue analgesia after surgery. However, analgesic block lasted significantly longer in patients receiving bupivacaine (P=0.03).
Conclusion. During sub-umbilical surgery, caudal levobupivacaine, ropivacaine and bupivacaine provided comparable analgesic efficacy. Bupivacaine produced a higher incidence of residual motor blockade and a longer analgesic block than ropivacaine and levobupivacaine.

Size 2 ProSeal^TM laryngeal mask airway: a randomized, crossover investigation with the standard laryngeal mask airway in paediatric patients
K. Goldmann and C. Jakob
British Journal of Anaesthesia 2005 94(3):385-389 

Background. One of the main concerns with the use of the standard laryngeal mask airway (SLMA) in small infants is that its low-pressure seal might be inadequate for positive pressure ventilation so that there is a risk of gas leakage into the stomach with the subsequent risk of regurgitation. The new ProSeal^TM LMA (PLMA) has been shown to form a more effective seal than the SLMA and to facilitate gastric tube placement in adults. The first paediatric size PLMA became available recently.
Methods. Thirty anaesthetized, non-paralysed children aged 46 (19) months, weighing 16 (10–21) kg, were studied. The SLMA and PLMA were inserted in random order into each patient. Airway leak pressure and maximum tidal volume were measured. Ease of insertion, quality of initial airway and fibreoptic position were also determined. Gastric tube placement was assessed for the PLMA.
Results. The airway leak pressure and maximum tidal volume were significantly higher for the PLMA (P=0.001). Ease of insertion and quality of initial airway were similar for both devices. Air entry into the stomach occurred more frequently with the SLMA (P=0.005). Gastric tube placement was possible in all patients.
Conclusions. The size 2 PLMA offered some advantages over the same size of SLMA in this crossover investigation. The high reliability of gastric tube placement and the significantly increased airway leak pressure might have important implications for use of this device for positive pressure ventilation in infants.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Landiolol attenuates tachycardia in response to endotracheal intubation without affecting blood pressure
Akinori Yamazaki, MD, Hiroyuki Kinoshita, MD PhD, Manabu Shimogai, MD, Keisuke Fujii, MD, Katsutoshi Nakahata, MD, Yasuo Hironaka, MD, Hiroshi Iranami, MD and Yoshio Hatano, MD
Canadian Journal of Anesthesia 52:254-257 (2005)

Purpose: Beta-adrenergic receptor antagonists (ß-antagonists) have long been used to control perioperative tachyarrhythmias. The effects of a ß 1-antagonist, landiolol, on perioperative hemodynamics are unknown. We aimed to determine the appropriate dosage of landiolol for the treatment of hemodynamic changes in response to endotracheal intubation.
Methods: Sixty-four patients without heart disease or hypertension, were assigned to receive saline (group C) or landiolol (0.1 or 0.3 mg·kg^-1; groups L1 and L3). Anesthesia was induced with propofol (2 mg·kg^-1 iv) followed by saline or landiolol iv. After ventilation with facemask using 2% sevoflurane in 100% oxygen for 90 sec, endotracheal intubation was performed. After intubation, anesthesia was maintained using 1% sevoflurane in combination with 50% nitrous oxide. Values of heart rate and mean arterial blood pressure were recorded before induction to five minutes after intubation.
Results: In group C, heart rate and mean blood pressure increased simultaneously after tracheal intubation, compared with baseline values. Heart rate values were attenuated immediately before as well as after intubation in group L3, compared with groups C and L1. Heart rate did not increase after tracheal intubation in group L1, compared with baseline. In contrast, mean arterial blood pressure values did not differ among groups.
Conclusions: The newly developed ß 1-antagonist landiolol (0.1 and 0.3 mg·kg^-1) may help prevent tachycardia without affecting blood pressure during the induction of anesthesia.

Canadian pediatric anesthesiologists prefer inhalational anesthesia to manage difficult airways: a survey
Peter Brooks, FRCA, Ron Ree, MD, David Rosen, FRCP and Mark Ansermino, FFA
Canadian Journal of Anesthesia 52:285-290 (2005)

Purpose: To survey Canadian pediatric anesthesiologists to assess practice patterns in managing pediatric patients with difficult airways.
Methods: Canadian pediatric anesthesiologists were invited to complete a web survey. Respondents selected their preferred anesthetic and airway management techniques in six clinical scenarios. The clinical scenarios involved airway management for cases where the difficulty was in visualizing the airway, sharing the airway and accessing a compromised airway.
Results: General inhalational anesthesia with spontaneous respiration was the preferred technique for managing difficult intubation especially in infants (90%) and younger children (97%), however, iv anesthesia was chosen for the management of the shared airway in the older child (51%) where there was little concern regarding difficulty of intubation. Most respondents would initially attempt direct laryngoscopy for the two scenarios of anticipated difficult airway (73% and 98%). The laryngeal mask airway is commonly used to guide fibreoptic endoscopy. The potential for complete airway obstruction would encourage respondents to employ a rigid bronchoscope as an alternate technique (17% and 44%).
Conclusion: Inhalational anesthesia remains the preferred technique for management of the difficult pediatric airway amongst Canadian pediatric anesthesiologists. Intravenous techniques are relatively more commonly chosen in cases where there is a shared airway but little concern regarding difficulty of intubation. In cases of anticipated difficult intubation, direct laryngoscopy remains the technique of choice and fibreoptic laryngoscopy makes a good alternate technique. The use of the laryngeal mask airway was preferred to facilitate fibreoptic intubation.

Modified Mallampati test, thyromental distance and inter-incisor gap are the best predictors of difficult laryngoscopy in West Africans
Nkihu A. Merah, FWACS, David T. Wong, MD, Dorothy J. Ffoulkes-Crabbe, FRCA, Olusola T. Kushimo, FRCA and Christopher O. Bode, FWACS
Canadian Journal of Anesthesia 52:291-296 (2005)

Purpose: To determine the ability to predict difficult visualization of the larynx (DVL) from the following preoperative airway predictive indices, in isolation and combination: modified Mallampati test (MMT), thyromental distance (TMD), sternomental distance (SMD), horizontal length of the mandible (HLM) and inter-incisor gap (IIG).
Methods: Three hundred and eighty consecutive patients undergoing general anesthesia were evaluated using the MMT, TMD, SMD, HLM and IIG and the cut-off points for the airway predictors were Mallampati III and IV; ≥ 6.5 cm, ≤ 13.5 cm, ≤ 9.0 cm and ≤4.0 cm respectively. During direct laryngoscopy, the laryngeal view was graded using the Cormack and Lehane (CL) classification. CL grades III and IV were considered difficult visualization. Sensitivity, specificity and positive predictive value for each airway predictor in isolation and in combination were determined. Logistic regression analysis was used to determine independent predictors of DVL.
Results: Difficulty to visualize the larynx was found in 13 (3.4%) patients. The sensitivity, specificity and the positive predictive value for the five airway predictors were: MMT (61.5%; 98.4%; 57.1%), TMD (15.4%; 98.1%; 22.2%), SMD (0%; 100%; 0%), HLM (30.8%, 76.0%; 4.3%) and IIG (30.8%; 97.3%; 28.6%). The best combination of predictors was MMT/TMD/IIG with a sensitivity, specificity and positive predictive value of 84.6%; 94.6%; 35.5% respectively. Logistic regression analysis showed that weight, MMT, IIG and TMD were independent predictors of DVL.
Conclusion: MMT, TMD and IIG appear to provide the optimal combination in prediction of DVL in a West African population.

Propofol is superior to thiopental for intubation without muscle relaxants
Samar Taha, MD, Sahar Siddik-Sayyid, MD FRCA, Mahmoud Alameddine, MD, Christiane Wakim, MD, Chadi Dahabra, MD, Adib Moussa, MD, Mohammed Khatib, PhD and Anis Baraka, MD FRCA
Canadian Journal of Anesthesia 52:249-253 (2005)

Purpose: To compare intubating conditions and cardiovascular changes following induction of anesthesia and tracheal intubation in patients receiving either lidocaine-remifentanil-propofol or lidocaine-remifentanil-thiopental prior to induction.
Methods: In a randomized, double-blind study 76 healthy adult patients were assigned to one of two groups: lidocaine 1.5 mg·kg^-1, remifentanil 2 µg·kg^-1 and propofol 2 mg·kg^-1 (Group P) or lidocaine 1.5 mg·kg^-1, remifentanil 2 µg·kg^-1 and thiopental 5 mg·kg^-1 (Group T). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient’s response to intubation and slow inflation of the tracheal cuff. The mean arterial pressure (MAP) and heart rate (HR) were measured 45 sec after hypnotic agent administration, immediately after tracheal intubation, two and five minutes after intubation.
Results: Excellent intubating conditions were obtained in 84% of Group P patients and 50% of Group T patients (P < 0.05). The percentage decrease from baseline MAP was significantly higher in Group P than in Group T postinduction (27.4% ± 11.6 vs 21.8% ± 10.0) and immediately postintubation (19.0% ± 16.7 vs 11.2% ± 14.9). The percentage change from baseline HR was significantly higher in Group P than in Group T postinduction (13.8% ± 9.7 vs 0.5% ± 12.4), immediately postintubation (8.7% ± 13.7 vs 2.1% ± 13.1), and two minutes postintubation (7.04% ± 14.3 vs 3.5% ± 14.3).
Conclusion: Lidocaine-remifentanil-propofol is superior to lidocaine-remifentanil-thiopental for tracheal intubation without muscle relaxants. However, it induces more hypotension and bradycardia.

PUB MED - TOP

The ProSeal laryngeal mask airway in children.
Lopez-Gil M, Brimacombe J.
Paediatr Anaesth. 2005 Mar;15(3):229-34.

Summary Background: The ProSeal^TM (PLMA) is a new laryngeal mask device with a modified cuff to improve the seal and a drain tube to provide access to the gastrointestinal tract. We assessed the performance of the size 2 (which has no dorsal cuff) and size 3 (which has a dorsal cuff) in terms of insertion success, efficacy of seal, tidal volume, gas exchange, fiberoptic position, gastric tube placement and frequency of problems.
Methods: Eighty children undergoing minor surgery were studied (n = 40, size 2 PLMA, weight 10-25 kg; n = 40, size 3 PLMA, weight >25-50 kg). Induction was with remifentanil and propofol. Insertion was with the introducer tool and by experienced users. Maintenance was with propofol or sevoflurane and pressure controlled ventilation.
Results: The first-time and overall insertion success rate was 84 and 100%, respectively. Oropharyngeal leak pressure was 31 +/- 5 cm H₂O. There were no gastric or drain tube air leaks. Tidal volume and gas exchange was adequate in all patients, other than two brief episodes of hypoxia because of airway reflex activation. The vocal cords and epiglottis were visible in 99 and 80%, respectively, via the airway tube. The first-time and overall insertion success rate for gastric tube insertion was 87 and 100%, respectively. During maintenance, the PLMA was removed in one patient with airway reflex activation and another required epinephrine for bronchospasm. There were no differences in performance between the sizes 2 and 3 PLMA.
Conclusion: The PLMA is an effective airway device in children and isolates the glottis from the esophagus when correctly positioned. Despite the lack of a dorsal cuff, the performance of the size 2 was similar to the size 3 PLMA in the age groups tested.

Do selective cyclo-oxygenase-2 inhibitors have a future?
Bannwarth B.
Drug Saf. 2005;28(3):183-9.

The dramatic withdrawal of rofecoxib on 30 September 2004, along with safety concerns about other cyclo-oxygenase (COX)-2 inhibitors (especially valdecoxib), raises important issues for clinicians, pharmaceutical companies and regulatory authorities. Some of these are examined in this article, including: (i) was the cardiotoxicity of rofecoxib evident long before its withdrawal?; (ii) is the thrombotic hazard a class effect that is applicable to all COX-2 inhibitors?; (iii) may conventional NSAIDs also confer a risk of cardiovascular thrombosis?; and (iv) is there any future for selective COX-2 inhibitors?

Intra-articular ropivacaine 0.75% and bupivacaine 0.50% for analgesia after arthroscopic knee surgery: A randomized prospective study.
Marret E, Gentili M, Bonnet MP, Bonnet F.
Arthroscopy. 2005 Mar;21(3):313-6.

PURPOSE: Intra-articular administration of local anesthetic solution provides analgesia after arthroscopic knee surgery. Bupivacaine is considered the gold standard local anesthetic in this indication, but ropivacaine, which is less toxic than bupivacaine, can consequently be administered in higher doses, potentially increasing the duration of analgesia. We compared the analgesic effect of intra-articular injection of ropivacaine 225 mg and bupivacaine 150 mg in patients undergoing arthroscopic surgery.
Type of Study: Double-blind, randomized prospective clinical study.
Methods: The study included 45 patients scheduled for knee meniscus repair under arthroscopy, who were allocated randomly into 3 groups to receive, intra-articularly, 30 mL of isotonic saline, bupivacaine 0.5%, or ropivacaine 0.75% solutions at the end of surgery. Postoperatively, pain was measured using a visual analog scale (VAS) at rest and on mobilization. Propacetamol was given when patients complained of pain.
Results: VAS scores at rest and on mobilization were higher in the saline group compared with the ropivacaine group ( P = .006 and P = .01, respectively). No difference in VAS scores was documented between bupivacaine and the saline groups. The median delay between the intra-articular administration and propacetamol administration was shorter in the saline group (15 minutes; range, 15 to 120 minutes) compared with the ropivacaine group (240 minutes; range 15 to 720 minutes) but no difference was documented between the bupivacaine group (30 minutes; range, 15 to 360 minutes) and the other 2 groups.
Conclusions: This level I study documents that intra-articular ropivacaine 0.75% provides better analgesia than bupivacaine 0.5% after knee arthroscopic surgery.

Desflurane and sevoflurane in elderly patients during general anesthesia: a double blind comparison.
Iannuzzi E, Iannuzzi M, Viola G, Cerulli A, Cirillo V, Chiefari M.
Minerva Anestesiol. 2005 Apr;71(4):147-55.

AIM: To investigate pulmonary wash-out of sevoflurane and desflurane and the quality of recovery from anesthesia in elderly patients.
METHODS: Thirty-six patients aged >65 years, ASA II, were assigned in a double blind fashion to either desflurane (n=18) or sevoflurane (n=18) anesthesia. All received propofol 2 mg/kg and remifentanil 0.2 microg/kg/min for induction and 0.6 mg/kg of rocuronium. When the trachea was intubated volatile anaesthetic was administered. All data were recorded 1, 3, 5, 15, 30 min after intubation and then every 15 min. All data were recorded 1, 2, 3, 4, 5 min after suspension of all agents. Once extubated simple orders and questions were given every minute, times of appropriate response were noted. The patients were then transferred to the recovery room, until discharge to the floor. Postoperative pain control was obtained by a continuous iv infusion of ketorolac 60 mg and tramadol 100 mg. The latter was incremented by supplemental boluses of 50 mg according to patient needs (VAS <4) up to a maximum of 300 mg/24h.
RESULTS: The F(A)/F(A0) ratio was lower in the desflurane group after halogenated agent suspension (p=/<0.05). Desflurane proved to have a faster wash out curve with respect to sevoflurane. Early recovery, as indicated by the time necessary to appropriately answer simple questions after the discontinuation of anesthetics, showed a significant advantage for desflurane (p=/<0.05). VAS was higher in the desflurane group as well as the needs for postoperative analgesia.
CONCLUSIONS: Patients receiving desflurane reported faster recovery from anesthesia but an earlier and more intense perception of pain after surgery.

Short-term analgesic effects of intra-articular injections after knee arthroscopy.
Goodwin RC, Amjadi F, Parker RD.
Arthroscopy. 2005 Mar;21(3):307-12.

PURPOSE: To study the effects of 3 different intra-articular analgesic combinations on postoperative pain, and whether the timing of the injection, either preoperative or postoperative, had an effect on postoperative analgesia.
Type of Study: Prospective, randomized, double-blind clinical trial.
Methods: Patients undergoing knee arthroscopy performed by a single surgeon under general anesthesia were randomized into 6 study groups. Each patient received an intra-articular injection 20 minutes before incision and at the end of the procedure. One injection contained the study medications, and the other contained normal saline solution (placebo). The patients, surgeon, and data collection personnel were blinded to the contents of the injections. Outcome measures included visual analogue pain scores at 0, 60, and 120 minutes after the procedure, and total recovery room fentanyl consumption.
Results: Fifty patients successfully completed the study protocol. Patients receiving combinations of morphine, bupivacaine, and epinephrine or bupivacaine and epinephrine yielded lower pain scores and narcotics consumption than patients receiving epinephrine alone, which was statistically significant irrespective of the timing of injection ( P < .0001). Patients receiving the study medication preoperatively had significantly lower pain scores at the first measurement (t = 0) than those receiving the study medication postoperatively ( P = .0343). There was no statistically significant effect of timing of the treatment medication administration at either 60 or 120 minutes postoperatively. Comparison of fentanyl consumption between groups receiving the treatment medication preoperatively versus postoperatively showed no significant difference.
Conclusions: The combination of morphine, bupivacaine, and epinephrine, as well as the combination of bupivacaine and epinephrine provide excellent postoperative pain control when used either preoperatively or postoperatively in knee arthroscopy. There was a trend that patients receiving preoperative analgesic injections experienced superior pain control than did those injected postoperatively. Level of Evidence: Level I, Randomized Controlled Trial.

Comparison of 4 anesthetic techniques for in vitro fertilization
Guasch E, Ardoy M, Cuadrado C, Gonzalez Gancedo P, Gonzalez A, Gilsanz F.
Rev Esp Anestesiol Reanim. 2005 Jan;52(1):9-18.

[Article in Spanish]

Little is known of the effect on oocytes of anesthesia administered during retrieval. The main objective of this study was to compare the prolactin and stress hormone responses to surgical stimulus under 4 anesthetic techniques and to determine whether there is an effect of technique on the number and quality of oocytes retrieved.
METHODS: We designed a clinical trial to determine the plasma and follicular levels of prolactin and cortisol in patients in an assisted reproduction program. The patients were randomized to 3 anesthetic groups: general anesthesia, spinal anesthesia, or sedation with alfentanil and midazolam plus paracervical block. Patients were consecutively assigned to the fourth group to receive sedation with remifentanil plus paracervical block.
RESULTS: We studied 90 patients. The patients receiving general anesthesia had the greatest increase in prolactin by the end of the procedure. Follicular cortisol increased in the paracervical block group in which remifentanil was used for sedation. The only significant difference between groups was seen for the rate of gestation of 0% in the group receiving sedation with alfentanil and midazolam before a paracervical block. Adverse effects were few with all the techniques. All patients reported a high degree of satisfaction.
CONCLUSIONS: Plasma increases in prolactin and hormonal responses to follicular puncture were fully attenuated by spinal anesthesia and partially attenuated by the techniques requiring sedation. None of the anesthetic techniques proved harmful to oocytes or embryos. Nor was the effectiveness of the in vitro fertilization technique affected by any of the anesthetic techniques studied.

Popliteal sciatic nerve block for ambulatory hallux valgus surgery
Suarez Ruiz P, Lopez Alvarez S, Sarmiento Penide A, Barbeito Vilarino MJ, Bonome Gonzalez C, Cobian Llamas JM.
Rev Esp Anestesiol Reanim. 2005 Jan;52(1):4-8

[Article in Spanish]

OBJECTIVE: The aim of this study was to assess the efficacy, effectiveness, technical difficulty, and clinical usefulness of the popliteal sciatic peripheral nerve block for unilateral hallus valgux surgery and to compare the posterior and lateral approaches. We also aimed to investigate patient comfort during the procedure.
MATERIALS AND METHODS: This prospective, randomized trial enrolled 60 patients scheduled for unilateral hallux valgus surgery. The patients were randomly assigned to groups of 30 patients to receive a nerve block by either a posterior or lateral approach. A nerve stimulator was used to locate the response of the two branches forming the sciatic nerve--the posterior tibial nerve and the common peroneal nerve. Then, 20 mL of 0.5% ropivacaine was injected for each nerve. Variables analyzed were efficacy, complications, quality and duration of postoperative analgesia, degree of comfort while the technique was being performed, and level of satisfaction.
RESULTS: The level of comfort was good for 19 patients (70%) in the posterior approach group and for 29 (97%) in the lateral approach group (P<0.05). Level of satisfaction was good or very good for 93% and 96% of the patients in the posterior and lateral approach groups, respectively. Block efficacy was excellent for 48 patients (80%), good for 9 (15%), and poor for 3 (5%), with no significant differences between the groups.
CONCLUSION: Both the posterior and lateral approaches provide easy access to the sciatic nerve for performing a block. The rate of success is high and postoperative analgesia is good, with no noteworthy complications. However, the lateral approach is more comfortable for the patient.

Office-based ambulatory anesthesia: Factors that influence patient satisfaction or dissatisfaction with deep sedation/general anesthesia.
Coyle TT, Helfrick JF, Gonzalez ML, Andresen RV, Perrott DH.
J Oral Maxillofac Surg. 2005 Feb;63(2):163-72.

PURPOSE: The purpose of this report was to analyze data collected in an outcomes study in an attempt to identify factors that may be significant predictors of either patient satisfaction or dissatisfaction with deep sedation/general anesthesia (DS/GA) administered in an office-based setting.
MATERIALS AND METHODS: To address the research purpose, we used a prospective cohort study design and sample of patients undergoing procedures in the office-based ambulatory setting of oral and maxillofacial surgeons practicing in the United States who received local anesthesia (LA), conscious sedation (CS), or DS/GA. The predictor variables were categorized as demographic, anesthetic technique, adverse events, and patient-oriented outcomes (satisfaction/dissatisfaction). Appropriate descriptive and exact P values were completed as indicated. Statistical significance was set at P < .05. Multivariate analyses were performed to support the interpretation of univariate findings.
RESULTS: The sample was composed of 34,191 patients, of whom 71.9% patients received DS/GA. There were 20,455 patient satisfaction forms completed, of which 14,912 forms were from patients undergoing DS/GA. Of patients who received DS/GA, 95.8% were extremely or moderately satisfied, 3.1% were neutral, and 1.1% moderately or extremely dissatisfied. Increased age and memory of postoperative instructions were identified as factors, which predicted satisfaction. The addition of nitrous oxide to some regimens also appeared to increase satisfaction. Young age, anxiety, pain, vomiting, and being awake during the procedure were predictors of dissatisfaction.
CONCLUSIONS: The findings of this study indicate that patients are overwhelmingly satisfied with DS/GA provided in an office-based ambulatory setting. Items identified as significant predictors of dissatisfaction (anxiety, pain, vomiting, being awake) generally confirm preexistent suppositions. Surprisingly, patient age (<10 years old) and memory of postoperative instructions appear to have relevance to dissatisfaction as well. Lack of specific regimens and controls prevents confirmation that nitrous oxide improves patient satisfaction rates. Although statistically significant, the variations, which resulted in a higher or lower satisfaction rate, are of questionable clinical significance in many cases.

Bispectral analysis during deep sedation of pediatric oral surgery patients.
Overly FL, Wright RO, Connor FA, Jay GD, Linakis JG.
J Oral Maxillofac Surg. 2005 Feb;63(2):215-9. 

PURPOSE: Bispectral (BIS) analysis uses electroencephalogram information from a forehead electrode to calculate an index score (0 to 100; 0 = coma; 90 to 100 = awake). This index score correlates with the level of alertness in anesthetized patients. Classically, sedation has been monitored with clinical sedation scales such as the Observers Assessment of Alertness Sedation Scale (OAA/S), Modified Ramsey Scale, or a Visual Analog Scale (VAS). Our objective was to determine the correlation between clinical sedation scales and BIS index in pediatric patients undergoing sedation in an outpatient oral surgery setting.
MATERIALS AND METHODS: Prospective cohort study of patients aged 2 to 17 years undergoing sedation in an outpatient oral surgery office. Sedation was performed in the customary manner with the addition of BIS monitoring. Three clinical sedation scores (OAA/S: 5 to 1; 5 = awake, 1 = unresponsive; Modified Ramsey: 1 to 6; 1-2 = awake, 6 = unresponsive; VAS: 0 to 10; 0 = awake, 10 = unresponsive) were assigned every 5 minutes by an investigator blinded to the BIS index. Data were analyzed using a repeated measures linear regression model.
RESULTS: Sixteen subjects undergoing oral surgery, ages 4.5 years to 17 years, were enrolled, mean age 12.6 years +/- 4.3 years (standard deviation). Patients received methohexital in addition to 1 or more of the following: nitrous oxide, fentanyl, or midazolam. The results of the longitudinal regression analysis showed a highly significant association between the sedation scales and the BIS index.
CONCLUSION: The BIS monitor may be a useful adjunct in monitoring pediatric patients receiving sedation in the outpatient setting.

Comparison of the analgesic effects of intra-articular injections administered preoperatively and postoperatively in knee arthroscopy.
Goodwin RC, Parker RD
J Knee Surg. 2005 Jan;18(1):17-24

Perioperative injection of analgesic agents is widely used for postoperative pain control following knee arthroscopy. This prospective, randomized, double-blind study explored whether a preoperative analgesic injection offered better pain control than a postoperative injection. Patients undergoing knee arthroscopy under general anesthesia were randomized to receive a standardized combination of intra-articular bupivacaine, morphine, and epinephrine administered either 20 minutes prior to incision or at the end of the procedure. Outcome measures included visual analog pain scores at 0, 30, 60, 90, and 120 minutes after the procedure, total recovery room fentanyl consumption, total oral narcotics consumption for the first 24 hours after surgery, and a validated pain and satisfaction instrument. Of the 22 patients enrolled in the study, 21 successfully completed the study protocol. Pain scores, narcotics consumption, and overall patient satisfaction were not significantly different between the two groups. These findings indicate the timing of intra-articular analgesic injections during outpatient knee arthroscopy, either preoperatively or postoperatively, may be at the discretion of the surgeon.

Short-term analgesic effects of intra-articular injections after knee arthroscopy.
Goodwin RC, Amjadi F, Parker RD.
Arthroscopy. 2005 Mar;21(3):307-12

PURPOSE: To study the effects of 3 different intra-articular analgesic combinations on postoperative pain, and whether the timing of the injection, either preoperative or postoperative, had an effect on postoperative analgesia. Type of Study: Prospective, randomized, double-blind clinical trial.
Methods: Patients undergoing knee arthroscopy performed by a single surgeon under general anesthesia were randomized into 6 study groups. Each patient received an intra-articular injection 20 minutes before incision and at the end of the procedure. One injection contained the study medications, and the other contained normal saline solution (placebo). The patients, surgeon, and data collection personnel were blinded to the contents of the injections. Outcome measures included visual analogue pain scores at 0, 60, and 120 minutes after the procedure, and total recovery room fentanyl consumption.
Results: Fifty patients successfully completed the study protocol. Patients receiving combinations of morphine, bupivacaine, and epinephrine or bupivacaine and epinephrine yielded lower pain scores and narcotics consumption than patients receiving epinephrine alone, which was statistically significant irrespective of the timing of injection ( P < .0001). Patients receiving the study medication preoperatively had significantly lower pain scores at the first measurement (t = 0) than those receiving the study medication postoperatively ( P = .0343). There was no statistically significant effect of timing of the treatment medication administration at either 60 or 120 minutes postoperatively. Comparison of fentanyl consumption between groups receiving the treatment medication preoperatively versus postoperatively showed no significant difference.
Conclusions: The combination of morphine, bupivacaine, and epinephrine, as well as the combination of bupivacaine and epinephrine provide excellent postoperative pain control when used either preoperatively or postoperatively in knee arthroscopy. There was a trend that patients receiving preoperative analgesic injections experienced superior pain control than did those injected postoperatively.

TOP