Volume 3, Issue 6 S A M B A T A L K S - PAGE 3 November, 2003

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

A Comparison of Psoas Compartment Block and Spinal and General Anesthesia for Outpatient Knee Arthroscopy
Christopher J. Jankowski, MD, James R. Hebl, MD, Michael J. Stuart, MD, Michael G. Rock, MD, Mark W. Pagnano, MD, Christopher M. Beighley, MS, Darrell R. Schroeder, MS, and Terese T. Horlocker, MD
Anesth Analg 2003;97:1003-1009

The optimal anesthetic technique for outpatient knee arthroscopy remains controversial. In this study, we evaluated surgical operating conditions, patient satisfaction, recovery times, and postoperative analgesic requirements associated with psoas compartment block, general anesthetic, or spinal anesthetic techniques. Sixty patients were randomized to receive a propofol/nitrous oxide/fentanyl general anesthetic, spinal anesthesia with 6 mg of bupivacaine and 15 µg of fentanyl, or psoas compartment block with 40 mL of 1.5% mepivacaine. All patients received IV ketorolac and intraarticular bupivacaine. The frequency of postanesthesia recovery room admission was 13 (65%) of 20 for patients receiving general anesthesia, compared with 0 of 21 for patients receiving spinal anesthesia and 1 (5%) of 19 for patients receiving psoas block (P < 0.001). The median time from the end of surgery to meeting hospital discharge criteria did not differ across groups (131, 129, and 110 min for general, spinal, and psoas groups, respectively). In the hospital, 45% of general anesthesia patients received opioid analgesics, compared with 14% of spinal anesthesia and 21% of psoas block patients (P = 0.087). There was no difference among groups with respect to the time of first analgesic use or the number of patients requiring opioid analgesia. Pain scores were highest in patients receiving general anesthesia at 30 min (P = 0.032) and at 60, 90, and 120 min (P < 0.001). Patient satisfaction with anesthetic technique (P = 0.025) and pain management (P = 0.009) differed significantly across groups; patients receiving general anesthesia reported lower satisfaction ratings. We conclude that spinal anesthesia or psoas block is superior to general anesthesia for knee arthroscopy when considering resource utilization, patient satisfaction, and postoperative analgesic management.
IMPLICATIONS: Outpatient knee arthroscopy may be performed using a variety of anesthetic techniques. We report that spinal anesthesia and psoas compartment block are superior to general anesthesia when considering resource utilization, patient satisfaction, and postoperative analgesic management.

The Use of Complementary and Alternative Medicines by Surgical Patients: A Follow-Up Survey Study
Shu-Ming Wang, MD, Alison A. Caldwell-Andrews, PhD, and Zeev N. Kain, MD
Anesth Analg 2003;97:1010-1015

In a previous study, we indicated that 42% of surgical outpatients are interested in using acupuncture as a treatment modality for preoperative anxiety. We designed this follow-up survey to assess differences in attitude toward complementary-alternative medical therapies (CAM) between patients undergoing outpatient surgeries and those undergoing inpatient surgeries. The results indicate that most surgical patients (57.4%) use some form of CAM, including self-prayer (praying for their own health; 29%), chiropractic treatment (23%), massage therapy (15%), relaxation (14%), herbs (13%), megavitamins (9%), and acupuncture (7%). Inpatient surgical respondents reported using self-prayer more than outpatient surgical respondents, but no other differences in CAM use were found between inpatient and outpatient respondents. More inpatient respondents reported disclosing their usage of CAM to perioperative physicians than did outpatient respondents. Most surgical patients were willing to accept CAM as part of their perioperative management but were not willing to pay out-of-pocket for CAM treatment. The leading CAM therapies that fewer of the respondents were willing to pay for out-of-pocket included relaxation, massage, chiropractic medicine, herbs, and acupuncture.
IMPLICATIONS: Most surgical patients use some form of complementary-alternative medical therapies (CAM) and are willing to accept CAM therapy as part of their perioperative management.

The Effects of Preoperative Inflammation on the Analgesic Efficacy of Intraarticular Piroxicam for Outpatient Knee Arthroscopy
Seval Izdes, MD, Sibel Orhun, MD, Sacit Turanli, MD, Ezgi Erkilic, MD, and Orhan Kanbak, MD
Anesth Analg 2003;97:1016-1019

We conducted a double-blinded study in 90 patients undergoing elective arthroscopic knee surgery to determine whether there is a role of inflammation in the analgesic efficacy of intraarticular piroxicam. Standardized general anesthetic techniques were used for all patients. At the end of the operation, after harvesting synovial biopsies, patients were randomized into three intraarticular groups equally. Group 1 received 25 mL saline, Group 2 received 25 mL 0.25% bupivacaine, and Group 3 received 25 mL 0.25% bupivacaine and piroxicam 20 mg. After microscopic examination of the synovial materials, the patients were divided into two subgroups, inflammation positive (I+) and inflammation negative (I-). Preoperatively and postoperatively at 1, 2, 4, and 6 h, pain levels, analgesic duration, and postoperative analgesic consumption were recorded. Analgesic duration was significantly longer in the I+ subgroup than the I- subgroup of Group 3 (P < 0.05). Pain scores at 1, 2, and 4 h postoperatively were significantly lower in the I+ subgroup than the I- subgroup of Group 3 (P < 0.05), whereas there were no significant differences among the subgroups of Group 1 and 2. We concluded that preoperative inflammation is one of the most important determinants of analgesic efficacy of intraarticular piroxicam.
IMPLICATIONS: Intraarticular administration of piroxicam along with bupivacaine improves postoperative analgesia in synovial inflammation before surgery.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Piroxicam gel, compared to EMLA cream is associated with less pain after venous cannulation in volunteers
Amitabh Dutta, MD, Goverdhan Dutt Puri, MD PhD and Jyotsna Wig, MD FAMS
Canadian Journal of Anesthesia 50:775-778 (2003)

Purpose: To evaluate and compare the analgesic efficacy and anti-inflammatory effects of topical piroxicam gel vs eutectic mixture of local anesthetic (EMLA) cream applied to the peripheral venous cannulation site in adult volunteers.
Methods: Piroxicam gel and EMLA cream were randomly applied on the dorsum of the right and left hand of ten volunteers who acted as their own control. A venous cannula was inserted (no iv infusion) and removed after one hour. Pain scores and signs of inflammation were noted at the cannulation site up to 48 hr.
Results: Pain scores with piroxicam gel were higher on cannulation and on advancement of the cannula (P < 0.05). Thereafter, pain scores were significantly higher with EMLA (P < 0.05). Blanching was present at all the peripheral venous sites treated with EMLA cream. Signs of inflammation (erythema, edema) were not more frequent with EMLA than with piroxicam (P > 0.05). Induration was more frequent with EMLA at six hours.
Conclusion: In volunteers EMLA cream is associated with less pain on cannulation and cannula advancement compared to piroxicam gel. Topical application of piroxicam gel before peripheral venous cannulation alleviates pain and, possibly, inflammation in the period subsequent to cannulation itself.

The anterior combined approach via a single skin injection site allows lower limb anesthesia in supine patients
Pierre Pandin, MD, Nathalie Vancutsem, MD, Jean Corentin Salengros, MD, Isabelle Huybrechts, MD and Arlette Vandesteene, MD PhD
Canadian Journal of Anesthesia 50:801-804 (2003)

Purpose: Lower limb anesthesia (LLA) requires the combination of, at least, three-in-one and sciatic nerve (SCN) blocks. Anterior approaches are easier to perform with minimal discomfort in supine patients, specially for traumatology. Feasibility of a single needle entry combined approach is reported.
Clinical features: The combined landmark was applied in 119 ASA I and II patients (32–68 yr) scheduled for surgery below the knee. Needle (nerve stimulation applied through a single 150-mm long b-bevelled insulated needle) was inserted at the midpoint between the two classical approaches. Thirty and 15 mL of 0.5% ropivacaine were injected close to the femoral and the SCN, respectively. During the following 45 min, the extent of sensory block and knee and ankle motor block were assessed.
Landmarks were determined within 1.7 min (0.7–2.2 min). The entire procedure was performed within 4.2 min (2.9–7.1 min) from the determination of the landmark to the SCN infiltration. The three-in-one technique was successful in 89.9% while SCN was successful in 94.9%. Femoral and tibial nerves were always blocked. Blockade of the posterior cutaneous femoral nerve was observed in 78% of patients. The extent and the quality of the sensory block always allowed surgery. Additional iv sedation was needed in 32.6% of patients. Motor block (adapted Bromage’s scale > 2) was observed in the femoral (98.3%), the obturator (84.8%), the tibial (97.4%) and the common peroneal (85.7%) nerve distributions. No important adverse effects were recorded.
Conclusion: The anterior combined approach via a single needle entry represents a technically easy and reliable technique to perform LLA in the supine patient.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Unusual foreign body in the esophagus: A challenge for the anesthesiologist Acta
J. Abrão, K. M. Khabbaz, J. M. Abrão, D. J. Coutinho, E. A. C. Juliano
Anaesthesiologica Scandinavica Volume 47: Issue 9, 1176-1177

A foreign body in the esophagus is usually removed by endoscopy. An elder man entered the emergency room dyspneic and dysphagic. A chest X-ray showed that he had a table fork stuck in the upper esophagus. An endoscopist tried to remove it without success. After bilateral block of the superior laryngeal nerve, transtracheal injection, topical anesthesia of the mouth, and sedation, an awake laryngoscopy was carried out. Pushing the laryngoscope into the opening of the esophagus the fork was seen and extracted by the anesthesiologist. This case focuses on the role of the anesthesiologist in the removal of esophageal foreign bodies.

Changes in onset time of rocuronium in patients pretreated with ephedrine and esmolol – the role of cardiac output
T. Ezri, P. Szmuk, R. D. Warters, R. E. Gebhard, E. G. Pivalizza, J. Katz
Acta Anaesthesiologica Scandinavica Volume 47: Issue 9, Pages 1067-1072

Background: We investigated the hypothesis that manipulation of cardiac output (CO) with esmolol (Es) or ephedrine (E) affects the onset time of rocuronium.
Methods: Following anesthesia induction, 33 patients received E (70 µg kg^-1), Es (500 µg kg^-1) or placebo (P) 30 s before rocuronium (0.6 mg kg^-1) administration. Cardiac output was measured non-invasively after intubation every 3 min. The interval from the end of rocuronium administration to the disappearance of all twitches was considered to be the onset time.
Results: Onset time was shorter after E (52.2 ± 16.5 s) and longer after Es (114.3 ± 11.1 s) compared with P (87.4 ± 7.3 s) (P < 0.0001). Cardiac output increased (P < 0.05) in group E for 15 min after rocuronium. In group Es, CO decreased (P < 0.05) at 3 and 6 min. Cardiac output was higher in group E vs. group Es, 3–6 min post administration of rocuronium (P=0.015).
Conclusion: Pretreatment with E or Es appears to affect the onset time of rocuronium by altering CO as measured with the NICO^TM (Non-Invasive Cardiac Output) monitor (Novametrix Medical Systems Inc., Willingford, CO).

BRITISH JOURNAL OF ANAESTHESIA - TOP

Comparison of end-tidal and transcutaneous measures of carbon dioxide during general anaesthesia in severely obese adults
J. Griffin, B. E. Terry, R. K. Burton, T. L. Ray, B. P. Keller, A. L. Landrum, J. O. Johnson and J. D. Tobias
Br J Anaesth 2003; 91: 498–501


Background. Patients with severe obesity (body mass index (BMI) greater than 35 kg m^–2) present difficulties for end-tidal carbon dioxide (_CO2) monitoring. Previous studies suggest that transcutaneous (TC) carbon dioxide measurements could be valuable, so we compared and TC measures with Pa_CO2 in severely obese patients during anaesthesia.
Methods. We studied patients with severe obesity (BMI 40 kg m^–2) undergoing gastric bypass surgery. Carbon dioxide was measured with both and TC devices. The difference between each measure (_CO2and TC-CO₂) and the Pa_CO2 was averaged for each patient to provide one value, and data compared with a non-paired, two-way t-test, Fisher’s exact test.
Results. We studied 30 adults (aged 18–54 yr, mean 41, SD 8.0 yr; weight: 115–267 kg, mean 162, SD 35 kg). The absolute difference between the TC-CO₂ and Pa_CO2 was 0.2 (0.2) (mean, SD) kPa while the absolute difference between the _CO2 and Pa_CO2 was 0.7 (0.4) kPa (P<0.0001). The bias and precision were +0.1 (0.3) kPa for TC vs arterial carbon dioxide and –0.7 (0.4) kPa for vs arterial carbon dioxide.
Conclusions. Transcutaneous carbon dioxide monitoring provides a better estimate of Pa_CO2 than _CO2 in patients with severe obesity.

Recovery of elderly patients from two or more hours of desflurane or sevoflurane anaesthesia
J. E. Heavner, A. D. Kaye, B.-K. Lin and T. King
Br J Anaesth 2003; 91: 502–6

Background: The solubility of desflurane compared with sevoflurane suggests more rapid recovery from desflurane anaesthesia. This could be important after prolonged anaesthesia and fast recovery may be advantageous in the elderly where slow recovery of mental function is a concern. We compared emergence from desflurane vs sevoflurane in elderly patients undergoing two or more hours of anaesthesia.
Methods: Fifty ASA physical status I, II, or III patients, 65 yr of age or older, undergoing anaesthesia expected to last two or more hours were randomly assigned to receive desflurane/nitrous oxide or sevoflurane/nitrous oxide anaesthesia. Patients were given 1–2 µg kg^–1 fentanyl i.v. and anaesthesia was induced with propofol 1.5–2.5 mg kg^–1 i.v. and maintained with either desflurane 2–6% or sevoflurane 0.6–1.75% with nitrous oxide 65% in oxygen. Inspired anaesthetic concentrations were adjusted to obtain adequate surgical anaesthesia and to maintain mean arterial pressure within 20% of baseline values. Early and intermediate recovery times were recorded. Digit-Symbol Substitution Test (DSST) scores and Visual Analog Scale (VAS) scores for pain and nausea were recorded before pre-medication and every 15 min in the Post Anaesthesia Care Unit (PACU) until patients were discharged.
Results: Early recovery times are given as median, quartiles. The times to extubation (5 (4–9); 9 (5–13) min), eye opening (5 (3–5); 11 (8–16) min), squeezing fingers on command (7 (4–9); 12 (8–17) min); and orientation (7 (5–9); 16 (10–21) min) were significantly less (P<0.05) for desflurane than for sevoflurane. Intermediate recovery, as measured by the DSST and time to ready for discharge from the PACU (56 (35–81); 71 (61–81) min) was similar in the two groups.
Conclusions: Early but not intermediate recovery times of elderly patients undergoing a wide range of surgical procedures requiring two or more hours of anaesthesia is significantly (P0.05) faster after desflurane.

Early recovery after remifentanil-pronounced compared with propofol-pronounced total intravenous anaesthesia for short painful procedures
C. Hackner, O. Detsch, G. Schneider, S. Jelen-Esselborn and E. Kochs
Br J Anaesth 2003; 91: 580–2

Background: We compared recovery from high-dose propofol/low-dose remifentanil (‘propofol-pronounced’) compared with high-dose remifentanil/low-dose propofol (‘remifentanil-pronounced’) anaesthesia.
Methods: Adult patients having panendoscopy, microlaryngoscopy, or tonsillectomy were randomly assigned to receive either propofol-pronounced (propofol 100 µg kg^-1 min^-1; remifentanil 0.15 µg kg^-1 min^-1) or remifentanil-pronounced (propofol 50 µg kg^-1 min^-1; remifentanil 0.45 µg kg^-1 min^-1) anaesthesia. In both groups, the procedure was started with remifentanil 0.4 µg kg^-1, propofol 2 mg kg^-1, and mivacurium 0.2 mg kg^-1. Cardiovascular measurements and EEG bispectral index (BIS) were recorded. To maintain comparable anaesthetic depth, additional propofol (0.5 mg kg^-1) was given if BIS values were greater than 55 and remifentanil (0.4 µg kg^-1) if heart rate or arterial pressure was greater than 110% of pre-anaesthetic values.
Results: Patient and surgical characteristics, cardiovascular measurements, and BIS values were similar in both groups. There were no differences in recovery times between the groups (time to extubation: 12.7 (4.5) vs 12.0 (3.6) min, readiness for transfer to the recovery ward: 14.4 (4.4) vs. 13.7 (3.6) min, mean (SD)).
Conclusions: In patients having short painful surgery, less propofol does not give faster recovery as long as the same anaesthetic level (as indicated by BIS and clinical signs) is maintained by more remifentanil. However, recovery times were less variable following remifentanil-pronounced anaesthesia suggesting a more predictable recovery.

ANESTHESIOLOGY - TOP

Acetazolamide Reduces Referred Postoperative Pain after Laparoscopic Surgery with Carbon Dioxide Insufflation
Harvey J. Woehlck, M.D.; Mary Otterson, M.D.; Hyun Yun, Ph.D. ; Lois A. Connolly, M.D.; Daniel Eastwood, M.S. ; Krista Colpaert, R.N.
Anesthesiology 2003; 99(4):924-928

Background: Carbon dioxide is the preferred insufflating gas for laparoscopy because of greater safety in the event of intravenous embolism, but it causes abdominal and referred pain. Acidification of the peritoneum by carbonic acid may be the major cause of pain from carbon dioxide insufflation. Carbonic anhydrase is an enzyme that increases the rate of carbonic acid formation from carbon dioxide. Because acetazolamide inhibits carbonic anhydrase, the authors hypothesized that the pain caused by carbon dioxide insufflation may be decreased by the administration of acetazolamide.
Methods: A prospective, randomized, double-blind study of 38 patients undergoing laparoscopic surgery during general anesthesia was performed. Acetazolamide (5 mg/kg) or a saline placebo was administered intravenously during surgery. Pain was rated on a visual analog scale (0-10) at four times: when first awake, at discharge from the recovery room, when discharged from the hospital, and on the day after surgery. The site and quality of pain were recorded, as were medications and side effects.
Results: Initial referred pain scores were lower after acetazolamide (1.00 ± 1.98; n = 18) than after placebo (3.40 ± 3.48; n = 20; P = 0.014), and 78% of patients in the acetazolamide group had no referred pain; however, only 45% patients in the placebo group had no referred pain. Incisional pain scores were not statistically different, and referred pain scores were similar at later times.
Conclusions: Acetazolamide reduces referred but not incisional pain after laparoscopic surgical procedures. The duration of pain reduction is limited to the immediate postsurgical period.

Comparative Neurotoxicity of Intrathecal and Epidural Lidocaine in Rats
Yumiko Kirihara, D.V.M. ; Yoji Saito, M.D. ; Shinichi Sakura, M.D. ; Keishi Hashimoto, M.D. ; Tomomune Kishimoto, M.D.; Yukihiko Yasui, D.D.S.
Anesthesiology 2003; 99(4):961-968

Background: Although there is a considerable difference in the number of clinical reports of neurologic injury between spinal anesthesia and other regional techniques, there are no animal data concerning a difference in the local anesthetic neurotoxicity between intrathecal and epidural administration. In the current study, the functional and morphologic effects of lidocaine administered intrathecally and epidurally were compared in rats.
Methods: Male rats were implanted with an intrathecal or epidural catheter through L4-L5 vertebra in the caudal direction. In experiment 1, to determine relative anesthetic potency, 16 rats received repetitive injections of 2.5% lidocaine into intrathecal or epidural space in different volumes and were examined for tail flick test for 90 min. In experiment 2, to ascertain whether the relative potency obtained in experiment 1 would apply to other concentrations of lidocaine, additional rats received saline, 1%, 2.5%, or 5% lidocaine in a volume of 20 or 100 µl through the intrathecal or epidural catheter, respectively. In experiment 3, additional rats that received saline, 2.5% lidocaine, or 10% lidocaine in a volume of 20 or 100 µl through the intrathecal or epidural catheter, respectively, were examined for persistent functional impairment and morphologic damage.
Results: In experiment 1, the two techniques produced parallel dose-effect curves that significantly differed from each other. The potency ratio calculated was approximately 4.72 (3.65-6.07):1 for intrathecal:epidural lidocaine. In experiment 2, every lidocaine solution produced a similar increase in tail flick latency for the two techniques. In experiment 3, five of eight rats given 10% intrathecal lidocaine incurred functional impairment 4 days after injection, whereas no rats in the other groups did. Significantly more morphologic damage was observed in rats given 10% intrathecal lidocaine than in those given 10% epidural lidocaine.
Conclusions: Persistent functional impairment occurred only after intrathecal lidocaine. Histologic damage in the nerve roots and the spinal cord was less severe after epidural lidocaine than after intrathecal lidocaine. The current results substantiate the clinical impression that neurologic complications are less frequent after epidural anesthesia than after spinal anesthesia

Mouth Opening: A New Angle
Ian Calder, F.R.C.A.; John Picard, F.R.C.A.; Martin Chapman, F.R.C.A.; Caoimhe O'Sullivan, M.A.; H. Alan Crockard, D.Sc., F.R.C.S.
Anesthesiology 2003; 99(4):799-801

Background: The authors hypothesized that craniocervical extension occurs during normal mouth opening.
Methods: Twenty volunteers were studied. Interdental distance was measured at four different degrees of craniocervical extension.
Results: Interdental distance increased from 28 mm (95% confidence interval, 25-30) in slight flexion to 46 mm (95% confidence interval, 42-49) at full extension. Nearly maximal mouth opening was obtained with 26 degrees (95% confidence interval, 22-30) of craniocervical extension from neutral.
Conclusion: Craniocervical extension is an integral part of complete mouth opening in conscious subjects. Fixation of the craniocervical junction by disease, an internal or external fixation device, or technique may restrict mouth opening, with consequences for airway management.

Effect of Auditory Evoked Potential Index Monitoring on Anesthetic Drug Requirements and Recovery Profile after Laparoscopic Surgery: A Clinical Utility Study
Alejandro Recart, M.D.; Paul F. White, Ph.D., M.D.; Agnes Wang, M.S.; Irina Gasanova, Ph.D., M.D.; Stephanie Byerly, M.D.; Stephanie B. Jones, M.D.
Anesthesiology 2003; 99(4):813-818

Background:The auditory evoked potential (AEP) monitor provides an electroencephalogram-derived index (AAI) that has been reported to correlate with the central nervous system depressant effects of anesthetic drugs. This clinical utility study was designed to test the hypothesis that AAI-guided administration of the maintenance anesthetics and analgesics would improve their titration and thereby provide a faster recovery from general anesthesia.
Methods: Seventy consenting patients undergoing elective general surgery procedures were randomly assigned to either a control (standard clinical practice) or AEP-monitored group. Although the AEP monitor was connected to all patients, the information from the monitor was only made available to the anesthesiologists assigned to patients in the AEP-monitored group. In the AEP-monitored group, the inspired desflurane concentration was titrated to maintain an AAI value of 15-20. In the control group, the inspired desflurane concentration was varied based on standard clinical signs. The AAI values and hemodynamic variables, as well as end-tidal desflurane concentrations, were recorded at 3- to 5-min intervals. The recovery times to achieve a White fast-track score greater than 12 and an Aldrete score of 10, as well as the actual duration of the PACU stay, were evaluated at 5- to 10-min intervals. Patient satisfaction with recovery from anesthesia was assessed using a 100-point verbal rating scale at 24 h after surgery.
Results: The average intraoperative AAI value in the AEP-monitored group was significantly higher than in the control group (16 ± 5 vs. 11 ± 8, P < 0.05). Use of the AEP monitor reduced the desflurane requirement by 26% compared to the control group (P < 0.01). In addition, the AEP-monitored group received less intraoperative fentanyl (270 ± 120 vs. 390 ± 203 mcg, P < 0.05) and more rapidly achieved fast-track eligibility (29 ± 19 vs. 56 ± 41 min, P < 0.05). The time required to achieve an Aldrete score of 10 (60 ± 31 vs. 98 ± 55 min) and the duration of stay in the recovery room (78 ± 32 vs. 106 ± 54 min) were also significantly reduced in the AEP-monitored (vs. control) group (P < 0.05).
Conclusion: Use of AEP monitoring as an adjunct to standard clinical monitors improved titration of anesthetic drugs, thereby facilitating the early recovery process after laparoscopic surgery.

Severe Bradycardia during Spinal and Epidural Anesthesia Recorded by an Anesthesia Information Management System
Jonathan B. Lesser, M.D.; Kevin V. Sanborn, M.D.; Rytis Valskys, M.D.; Max Kuroda, Ph.D., M.P.H.
Anesthesiology 2003; 99(4):859-866

Background: Bradycardia and asystole can occur unexpectedly during neuraxial anesthesia. Risk factors may include low baseline heart rate, first-degree heart block, American Society of Anesthesiologists physical status - blockers, male gender, and high sensory level. Anesthesia information management systems automatically record large numbers of physiologic variables that are combined with data input from the anesthesiologist to form the anesthesia record. Such large databases can be scanned for episodes of bradycardia.
Methods: To select spinal and epidural anesthetics that did not also involve general anesthesia, 57,240 automated anesthesia records were scanned. Obstetrical patients and patients younger than age 12 yr were excluded. The electronic records selected were then scanned for episodes of moderate (heart rate < 50 and 40 beats/min) or severe (heart rate < 40 beats/min) bradycardia.
Results: A total of 6,663 cases (11.6%) met the inclusion criteria. Among the 677 cases of bradycardia (10.2%) were 46 cases of severe bradycardia (0.7%). In the final multivariate logistic regression analysis, baseline heart rate less than 60 beats/min (P0.0001) and male gender (P = 0.05) contributed significantly to risk for a severe bradycardia episode (odds ratio [OR]), 14.1 and 95% confidence interval [CI], 6.9-28.0, and OR, 2.1 and 95% CI, 1-4.3, respectively). For the 631 episodes of moderate bradycardia (9.5%), the final multivariate model included baseline heart rate less than 60 beats/min (OR, 16.2; 95% CI, 12.4-22.0), age younger than 37 yr (OR, 1.4; 95% CI, 1.1-1.7), male gender (OR, 1.4; 95% CI, 1.2-1.8), nonemergency status (OR, 1.7; 95% CI, 1.2-2.4), -blockers (OR, 1.6; 95% CI, 1.1-2.3), and case duration (OR, 2.0; 95% CI, 1.6-2.4) as significant risk factors. Time of occurrence of a bradycardia event was distributed widely across the entire duration of a case.
Conclusions: Moderate or severe bradycardia may occur at any time during neuraxial anesthesia, regardless of the duration of anesthesia. Low baseline heart rate increases the risk for bradycardia.

PUB MED - TOP

Unilateral spinal block for outpatient knee arthroscopy: a dose-finding study.
Borghi B, Stagni F, Bugamelli S, Paini MB, Nepoti ML, Montebugnoli M, Casati A.
J Clin Anesth. 2003 Aug;15(5):351-6.

To evaluate the onset time, success rate, and recovery profile of unilateral spinal anesthesia produced with 4 mg, 6 mg, and 8 mg of 0.5% hyperbaric bupivacaine. Prospective, randomized, blinded study. Outpatient anesthesia unit at a University Hospital. 90 ASA physical status I and II outpatients, who were scheduled for elective knee arthroscopy. After standard intravenous midazolam premedication (0.05 mg/kg) and crystalloid infusion (7 mL/kg) were given, patients were placed in the lateral decubitus position on the operative side, and randomly allocated to receive spinal block with either 4 mg (Group 4, n = 30), 6 mg (Group 6, n = 30), or 8 mg (Group 8, n = 30) of 0.5% hyperbaric bupivacaine injected slowly (3 mL/min) with the needle orifice directed toward the dependent side using a 25-gauge Whitacre needle. The lateral decubitus position was maintained for 15 minutes.The onset time of surgical block was 13 +/- 5 minutes in Group 4 and 10 +/- 4 minutes in Group 6 (p = 0.006), and 9 +/- 4 minutes in Group 8 (p = 0.002). The maximum level of sensory block on the operative and nonoperative sides was, respectively, T(10) (T(12)-T(6)) and / (/-L(2)) in Group 4 (p = 0.0005), T(8) (T(12)-T(6)) and / (/-L(5)) in Group 6 (p = 0.0005), and T(7) (T(12)-T(5)) and / (/-T(10)) in Group 8 (p = 0.0005). A strictly unilateral sensory block was observed in 27 Group 4 patients (90%), 28 Group 6 patients (93%) and 23 Group 8 patients (77%) (p = 0.28). Complete unilateral motor block was observed in 29 Group 4 patients (97%), 28 Group 6 patients (93%),
and 28 Group 8 patients (93%) (p = 0.80). No failed blocks were reported. Complete regression of spinal anesthesia required 71 +/- 20 minutes in Group 4 (range: 40 to 110 min), 82 +/- 25 minutes in Group 6 (range: 30 to 160 min), and 97 +/- 37 minutes in Group 8 (range: 50 to 120 min) (p = 0.003).Hyperbaric bupivacaine 4 mg injected slowly through pencil-point directional needles in patients who are maintained in the lateral decubitus position for 15 minutes provided a surgical block that was mostly restricted to the operative side and adequate to perform knee arthroscopy, with a faster recovery profile than when a 6 mg or 8 mg dose was used.

Lunar phase does not influence surgical quality.
Holzheimer RG, Nitz C, Gresser U.
Eur J Med Res. 2003 Sep 29;8(9):414-8.

Introduction: 10.5% of the German population believes in the effects of lunar phase on disease. The topic is hot in German TV program. It is believed that at new moon the rate of bleeding complications is increased and operations during the waning phase of the moon would be best to avoid complications, pain and scaring. To our knowledge the effect of lunar phase has not been studied in ambulatory surgery.
Patients and methods: 782 patients were evaluated for complications and perception of the personal health after herniotomy, haemorrhoidectomy and crossectomy with partial vein stripping with or without phlebectomy as part of a quality control study. A questionnaire has been sent out to the patients asking the patient to rate postoperative pain, pain medication, restriction of daily activity, mental health and emotion, status of complaints after the operation.
Results: In 782 patients (mean age 50 years) 866 operations were performed. There were no major complications and only in 3.71% minor complications (local bleeding, haematoma, inflammation, abscess, seroma, lymphatic fistula, dehiscence) were observed. The operations were equally distributed to the lunar phases. Complications and patient's subjective perception of pain, restriction of daily activity, mental health and emotion, status of complaints after the operation were not associated with a lunar phase.
Conclusion: The hypothesis that lunar phase influences the outcome of ambulatory operations is not valid. With regard to the organization of operations in the hospital and the patient's uncertainty to decide the right time the lunar phase philosophy may have an socio-economic impact not yet understood.

Office-based ambulatory anesthesia: outcomes of clinical practice of oral and maxillofacial surgeons.
Perrott DH, Yuen JP, Andresen RV, Dodson TB.
J Oral Maxillofac Surg. 2003 Sep;61(9):983-95; discussion 995-6.

PURPOSE: The delivery of office-based ambulatory anesthesia services is an integral component of the daily practice of oral and maxillofacial surgeons (OMSs). The purpose of this report was to provide an overview of current anesthetic practices of OMSs in the office-based ambulatory setting.
MATERIALS AND METHODS: To address the research purpose, we used a prospective cohort study design and a sample composed of patients undergoing procedures in the office-based ambulatory setting of OMSs practicing in the United States who received local anesthesia (LA), conscious sedation (CS), or deep sedation/general anesthesia (DS/GA). The predictor variables were categorized as demographic, anesthetic technique, staffing, adverse events, and patient-oriented outcomes. Appropriate descriptive and bivariate statistics were computed as indicated. Statistical significance was set at < or =.05.
RESULTS: The sample was composed of 34,191 patients, of whom 71.9% received DS/GA, 15.5% received CS, and 12.6% received LA. The complication rate was 1.3 per 100 cases, and the complications were minor and self-limiting. Two patients had complications requiring hospitalization. Most patients (80.3%) reported some degree of anxiety before the procedure. After the procedure, 61.2% of patients reported having no anxiety about future operations. Overall, 94.3% of patients reported satisfaction with the anesthetic, and more than 94.7% of all patients would recommend the anesthetic technique to a loved one.
CONCLUSION: The findings of this study show that the office-based administration of LA, CS, or DS/GA delivered via OMS anesthesia teams was safe and associated with a high level of patient satisfaction.