Volume 4, Issue 7 S A M B A T A L K S - PAGE 3 December, 2004

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

Review of Pediatric Sedation (REVIEW ARTICLE)
Joseph P. Cravero, MD, and George T. Blike, MD
Anesth Analg 2004;99:1355-1364

Sedating children for diagnostic and therapeutic procedures remains an area of rapid change and considerable controversy. Exploration of this topic is made difficult by the fact that the reports of techniques and outcomes for pediatric sedation appear in a wide range of subspecialty publications and rarely undergo comprehensive examination. In this review article, we will touch on many aspects of the topic of pediatric sedation from the perspective of the anesthesiologist. We begin with a review of the historical role of anesthesiologists in the development of the current standards for pediatric sedation. We also examine the current status of pediatric sedation as reflected in published studies and reports. A specific review of the issues surrounding safety of sedation services is included. Current trends in sedation practice, including the expanding role of potent sedative hypnotic drugs outside the field of anesthesiology, are noted. Finally, we suggest future areas for research and clinical improvement for sedation providers.

A Multiple-Dose Phase I Study of Intranasal Hydromorphone Hydrochloride in Healthy Volunteers
Anita C. Rudy, PhD, Barbara A. Coda, MD, Sanford M. Archer, MD, and Daniel P. Wermeling, PharmD
Anesth Analg 2004;99:1379-1386

We evaluated the pharmacokinetics, tolerability, and safety of 1 and 2 mg of intranasal hydromorphone hydrochloride in an open-label, single- and multiple-dose study. This Phase I study was conducted in 24 healthy volunteers (13 men and 11 women). Intranasal doses were delivered as 0.1-mL metered-dose sprays into one or both nostrils for 1- and 2-mg doses, respectively. Venous blood samples were taken serially from 0 to 12 h after the first single dose and the last (seventh) multiple dose. Plasma hydromorphone concentrations were determined by liquid chromatography/mass spectrometry/mass spectrometry. Noncompartmental analysis was used to estimate pharmacokinetic variables. After 7 intranasal doses of 1 and 2 mg (once every 6 h), mean ± SD peak plasma concentrations of 2.8 ± 0.7 ng/mL and 5.3 ± 2.3 ng/mL, respectively, were observed. The median time to peak concentration was 20 min for both single and multiple doses. Dose proportionality was observed for the 1- and 2-mg doses. Adverse events included somnolence, dizziness, and bad taste after dose administration. Intranasal hydromorphone hydrochloride was well tolerated and demonstrated rapid nasal drug absorption and predictable accumulation. These results support clinical investigation of hydromorphone hydrochloride nasal spray for use as an alternative to oral and IM administration.
IMPLICATIONS: Pharmacokinetics were determined for multiple doses of intranasal hydromorphone hydrochloride in healthy volunteers. Rapid absorption and predictable accumulation and pharmacokinetics support the investigation of hydromorphone hydrochloride nasal spray as a therapeutic alternative to oral and IM administration.

A Prospective, Randomized, Double-Blind Comparison of Unilateral Spinal Anesthesia with Hyperbaric Bupivacaine, Ropivacaine, or Levobupivacaine for Inguinal Herniorrhaphy
Andrea Casati, MD, Elena Moizo, MD, Chiara Marchetti, MD, and Federico Vinciguerra, MD
Anesth Analg 2004;99:1387-1392

In 60 patients undergoing inguinal hernia repair, we compared the clinical profile of unilateral spinal anesthesia produced with either 8 mg of hyperbaric bupivacaine 0.5% (n = 20), 8 mg of hyperbaric levobupivacaine 0.5% (n = 20), or 12 mg of hyperbaric ropivacaine 0.5% (n = 20). The study drug was injected slowly through a 25-gauge Whitacre directional needle and patients maintained the lateral decubitus position for 15 min. The onset time and intraoperative efficacy were similar in the three groups. The maximal level of sensory block on the operative and nonoperative sides was T6 (T12–5) and L3 (/[no sensory level detectable]–T4) with bupivacaine, T8 (T12–5) and L3 (/–T3) with levobupivacaine, T5 (T10–2) and T11 (/–T3) with ropivacaine (P = 0.11, P = 0.23, respectively). Complete regression of spinal anesthesia occurred after 166 ± 42 min with ropivacaine, 210 ± 63 min with levobupivacaine, and 190 ± 51 min with bupivacaine (P = 0.03 and P = 0.04, respectively); however, no differences were observed in time for home discharge (329 ± 89 min with bupivacaine, 261 ± 112 min with levobupivacaine, and 332 ± 57 min with ropivacaine [P = 0.28]). We conclude that 8 mg of levobupivacaine or 12 mg of ropivacaine are acceptable alternatives to 8 mg of bupivacaine when limiting spinal block at the operative side for inguinal hernia repair.
IMPLICATIONS: Comparing spinal block produced with 8 mg of hyperbaric bupivacaine 0.5%, 8 mg of hyperbaric levobupivacaine 0.5%, and 12 mg of hyperbaric ropivacaine 0.5%, this prospective, randomized, double-blind study demonstrated that all 3 local anesthetics have similarly short clinical profiles.

The Laryngeal Mask Airway Unique^TM versus the Soft Seal^TM Laryngeal Mask: A Randomized, Crossover Study in Paralyzed, Anesthetized Patients
Joseph Brimacombe, MD, Achim von Goedecke, MD, Christian Keller, MD, Lawrence Brimacombe, MB ChB, and Moira Brimacombe, MB ChB
Anesth Analg 2004;99:1560-1563

We tested the hypothesis that ease of insertion, oropharyngeal leak pressure, fiberoptic position, ease of ventilation, and mucosal trauma are different for the Soft Seal^TM laryngeal mask airway (SSLM) and the laryngeal mask airway Unique^TM (LMA-U). Ninety paralyzed, anesthetized adult patients (ASA I–II; 18–80 yr old) were studied. Both devices were inserted into each patient in random order. Oropharyngeal leak pressure and fiberoptic position were determined during cuff inflation from 0–40 mL in 10-mL increments and at an intracuff pressure of 60 cm H₂O. Ease of ventilation was determined by controlling ventilation for 10 min at 8 and 12-mL/kg tidal volume and recording hemoglobin oxygen saturation, end-tidal CO₂, leak fraction, peak airway pressure, and the presence or absence of gastric insufflation. Mucosal trauma was determined by examining the first randomized device for the presence of visible and occult blood. Insertion time was shorter (P = 0.0001) and fewer attempts were required (P = 0.005) for the LMA-U. There were no failed uses of either device. Oropharyngeal leak pressures were similar, but fiberoptic position was superior with the LMA-U (P0.0003). There were no differences in hemoglobin oxygen saturation, end-tidal CO₂, leak fraction, or peak airway pressure at either tidal volume. Gastric insufflation was not detected in either group at either tidal volume. The frequency of visible (P = 0.009) and occult blood (P = 0.0001) was less with the LMA-U. We conclude that the LMA-U is superior to the SSLM in terms of ease of insertion, fiberoptic position, and mucosal trauma, but similar in terms of oropharyngeal leak pressure and ease of ventilation.
IMPLICATIONS: The laryngeal mask airway Unique^TM is superior to the Soft Seal^TM laryngeal mask in terms of ease of insertion, fiberoptic position, and mucosal trauma but similar in terms of oropharyngeal leak pressure and ease of ventilation.

ANESTHESIOLOGY - TOP

Narcotrend^R Does Not Adequately Detect the Transition between Awareness and Unconsciousness in Surgical Patients.
Schneider, Gerhard M.D. ; Kochs, Eberhard F. M.D. ; Horn, Bettina M.D. ; Kreuzer, Matthias M.Sc.; Ningler, Michael M.Sc.
Anesthesiology 2004; 101( 5): 1105-1111.

Background: The Narcotrend^R index (MonitorTechnik, Bad Bramstedt, Germany) is a dimensionless number between 0 and 100 that is calculated from the electroencephalogram and inversely correlates with depth of hypnosis. The current study evaluates the capability of the Narcotrend^R to separate awareness from unconsciousness at the transition between these levels.
Methods: Electroencephalographic recordings of 40 unpremedicated patients undergoing elective surgery were analyzed. Patients were randomly assigned to receive (1) sevoflurane-remifentanil (<= 0.1 ug kg^-1 min^-1), (2) sevoflurane-remifentanil (>= 0.2 ug kg^-1 min^-1), (3) propofol-remifentanil (<= 0.1 ug kg^-1 min^-1), or (4) propofol-remifentanil (>= 0.2 ug kg^-1 min^-1). Remifentanil and sevoflurane or propofol were given until loss of consciousness. After tracheal intubation, propofol or sevoflurane was stopped until return of consciousness and then restarted to induce loss of consciousness. After surgery, drugs were discontinued. Narcotrend R values at loss and return of consciousness were compared with each other, and anesthetic groups were compared. Prediction probability was calculated from values at the last command before and at loss and return of consciousness.
Results: At 105 of 316 analyzed time points, the Narcotrend^R did not calculate an index, and the closest calculated value was analyzed. No significant differences between loss and return of consciousness were found. In group 1, Narcotrend^R values were significantly higher than in group 3. Prediction probability was 0.501.
Conclusions : In these challenging data, the Narcotrend^R did not differentiate between awareness and unconsciousness. In addition, Narcotrend^R values were not independent from the anesthetic regimen.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Rocuronium attenuates oculocardiac reflex during squint surgery in children anesthetized with halothane and nitrous oxide
N. Karanovic, M. Jukic, M. Carev, G. Kardum and Z. Dogas
Acta Anaesthesiologica Scandinavica 2004; 48:1301-5

Background: The oculocardiac reflex (OCR) may be activated during squint surgery. The aim of this study was to test whether rocuronium 0.4 mg kg^-1 could reduce the frequency of OCR, and also whether a single dose of succinylcholine 1 mg kg^-1 could affect the frequency of OCR during anesthesia with halothane in a nitrous oxide/oxygen mixture.
Methods: A total of 161 ASA I children, 3-10 years old, undergoing elective surgery of the medial rectus muscle (MRM) were randomly assigned to three groups. Group R (n = 51), received 0.4 mg kg^-1 of rocuronium intravenously before endotracheal intubation. Group S (n = 58) received 1 mg kg^-1 of succinylcholine. Group C (controls, n = 52) received no relaxant. Oculocardiac reflex was defined as a reduction in heart rate (HR) >= 15% and/or the appearance of any other arrhythmias, during manipulation of the MRM. Analysis of variance ( anova), chi-squared, Kruskal-Wallis, and Student's t-tests were used for statistical analysis; P< 0.05 was considered statistically significant.
Results: In group R, OCR occurred in 15/51 (29%) of children, in group S in 31/58 (53%), and in group C in 23/52 (44%) (Chi² = 6.46, P = 0.049). In group R, the incidence of arrhythmias such as nodal rhythms, supraventricular and ventricular premature beats was 6%, compared with 22% in group S and 19% in group C (Chi² = 6.01, P = 0.040). However, there was no reduction in the occurrence of bradycardia (Chi² = 0.16, P = 0.924).
Conclusion: Rocuronium reduced the frequency of OCR, mainly by reducing the incidence of supraventricular and ventricular premature beats.

Dixyrazine for the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy
C. Glaser, C. Sitzwohl , T. Wallner, A. Lerche, P. Marhofer and I. Schindler
Acta Anaesthesiologica Scandinavica 2004; 48:1287-91

Background: The study assessed the efficacy and safety of dixyrazine, an alternative neuroleptic drug to droperidol, in the prophylaxis of postoperative nausea and vomiting (PONV).
Methods:  A total of 197 patients scheduled for laparoscopic cholecystectomy under general anesthesia were randomized to receive either dixyrazine 10 mg or placebo double-blinded at the end of surgery. Scores pertaining to PONV episodes, analgetic supply, rescue medication, adverse events and patient satisfaction were collected over the first 2 h in the PACU and the next 22 h in the ward.
Results:  The incidence of PONV over the entire 24-h period was reduced from 32% in the placebo group to 13% in the dixyrazine group (P<=0.004). The incidence of nausea in the first 2 h was reduced from 15% in the placebo group to 4% in the dixyrazine group (P<=0.02) and from 12% to 5% in the next 22 h. The incidence of emetic episodes was not different between the two groups. Postoperative shivering was significantly less prevalent in the dixyrazine than in the placebo group (2% vs. 13%; P<=0008), and opioid analgesics were required significantly less often (61% vs. 75%; P<=0.01). No significant adverse effects were observed. Patient satisfaction was similar in both groups.
Conclusion:  Prophylactic dixyrazine is an effective, safe, and cheap antiemetic drug for laparoscopic cholecystectomy without involving any significant adverse events.
 

Similar excitation after sevoflurane anaesthesia in young children given rectal morphine or midazolam as premedication
W. Malmgren and J. Åkeson
Acta Anaesthesiologica Scandinavica2004; 48:1277-82

Background:  Sevoflurane is a rapid-acting volatile anaesthetic agent frequently used in paediatric anaesthesia despite transient postoperative symptoms of cerebral excitation, particularly in preschool children. This randomised and investigator-blinded study was designed to evaluate whether premedication with an opioid might reduce non-divertible postoperative excitation more than premedication with a benzodiazepine in preschool children anaesthetized with sevoflurane.
Methods:  Ninety-two healthy two to six year-old children scheduled for nasal adenoidectomy were randomised to be given rectal atropine 0.02 mg kg^-1 together with either morphine 0.15 mg kg^-1 or midazolam 0.30 mg kg^-1 approximately 30 min before induction and maintenance of sevoflurane anaesthesia. The patient groups were compared pre- and postoperatively by repeated clinical assessments of cerebral excitation according to a modified Objective Pain Discomfort Scale, OPDS.
Results : There were no statistically significant postoperative differences in incidence, extent or duration of excitation between children given morphine or midazolam for premedication, whereas morphine was associated with more preoperative excitation than was midazolam. The study groups did not differ significantly with respect to age, weight, duration of surgery and anaesthesia, and time from tracheal extubation to arrival in and discharge from the postoperative ward.
Conclusion : In this study morphine for premedication in young children anaesthetized with sevoflurane was associated with similar postoperative and higher preoperative OPDS scores compared with midazolam. These findings indicate that substitution of morphine for midazolam is no useful way of reducing clinical excitation after sevoflurane anaesthesia.

Clonidine vs. midazolam as premedication in children undergoing adeno-tonsillectomy: A prospective, randomized, controlled clinical trial 
H. T. G. Bergendahl, P. A. Lönnqvist, S. Eksborg, E. Ruthström, L. Nordenberg, H. Zetterqvist and E. Oddby
Acta Anaesthesiologica Scandinavica 2004; 48:1292 - 1300

Background:  Clonidine administration in the setting of paediatric anaesthesia is associated with a number of desirable effects, e.g. preoperative sedation, analgesia and reduced anaesthetic requirements. The aim of the current study was to compare postoperative outcome variables using a prospective, randomized, double-blind design after premedication with clonidine or midazolam.
Methods:  One hundred paediatric ASA physical status 1 patients (age 1-11 year) scheduled for adeno-tonsillectomy were assigned to receive rectal premedication with midazolam (300 µg kg^-1 and atropine 40 µg kg^-1; group M, n = 52) or clonidine (5 µg kg^-1 and atropine 40 µg kg^-1; group C, n = 48) prior to a standardized sevoflurane anaesthetic. The incidence of immediate postoperative pain (0-2 h), as assessed by repeated Objective Pain Scale (OPS) scores, was chosen as the primary end-point of the study. Degree of sedation (modified Vancouver sedation scale 0-3), occurrence of postoperative vomiting (POV), and incidence of shivering and immediate postoperative confusion were registered as secondary end-points. After hospital discharge parents were instructed to continue the evaluation of pain, sedation, POV and sleep pattern during a 24-h period. Parents were also asked for their preference concerning the postoperative behaviour of their child (calm, sedated vs. alert, active).
Results:  In the early postoperative period patients in the clonidine group had a significantly lower sum of 5 OPS scores (median = 8.0) compared to group M (median = 11.5) (P = 0.011). Administration of clonidine was also associated with a slightly higher sum of sedation scores (median = 13) in the early postoperative period compared to children receiving midazolam (median = 12) (P< 0.001). No episode of shivering was observed in the clonidine group but was present in five of the patients in the midazolam group (P = 0.057). In younger children (<5 years) the incidence of postoperative confusion was lower in the clonidine group (P = 0.001). No difference in the frequencies of POV incidences, degree of postoperative pain, need for analgesics, or sleep pattern during the first 24 postoperative hours could be observed between the groups according to the parental evaluation. Children premedicated with clonidine were more calm and sedated compared to children in the midazolam group (P = 0.024) as judged by their parents. A significant majority of parents (75%; P<0.001) preferred a calm and sedated child during the first postoperative 24-h period.
Conclusion:  Rectal premedication with clonidine was associated with a significant reduction of pain in the early postoperative period compared to midazolam and was also associated with moderately increased sedation during the first 24 postoperative hours. The sedative effect of clonidine is in agreement with the unambiguous finding of a parental preference for a calm and sedated child during the first 24 postoperative hours.

Women report more pain on injection of a precurarization dose of rocuronium: A randomized, prospective, placebo-controlled trial
T. Mencke, J. U. Schreiber, H. Knoll, C. Stracke, S. Kleinschmidt, H. Rensing and M. Silomon
Acta Anaesthesiologica Scandinavica 2004; 48:1245- 8

Background:  The purpose of this study was to investigate whether gender influences the perception of pain on injection of rocuronium.
Methods:  In this prospective, placebo-controlled trial 120 patients were randomized into four groups to receive rocuronium 0.03 mg kg^-1 (40 female and 40 male patients) or saline (20 female and 20 male patients). The incidence and severity of the injection pain after administration of the study drug was compared between female and male patients using a numerical rating scale (0-10). Signs of local irritation, i.e. erythema and thrombophlebitis, were assessed up to 48 h after surgery.
Results:  In 26 (32.5%) of the 80 patients receiving rocuronium, pain on injection was observed. This occurred significantly more frequently in the female compared with male patients: 18 (45%) vs. eight (20%), respectively (P = 0.032). The severity was more pronounced in the women than in the men (P = 0.020). The incidence of the rocuronium-associated pain was significantly increased compared with the Saline groups (P < 0.001). After surgery no patient complained of any residual pain and no local signs were observed in any patient during the study period.
Conclusions:  Women experienced more pain on injection of rocuronium than men, moreover this is an additional evidence for gender-related differences in pain perception. When rocuronium is used as a precurarization agent, an analgesic pretreatment (e.g. opioids) should be considered, especially for female patients.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Randomized double-blind clinical trial comparing topical and sub-Tenon's anaesthesia in routine cataract surgery
S. Srinivasan, A. I. Fern, S. Selvaraj and S. Hasan
British Journal of Anaesthesia 2004;93(5):683-686

Background. Several local anaesthetic techniques are available for cataract surgery. Recently, topical anaesthesia has gained in popularity. A randomized trial was designed to compare patient discomfort and intraoperative complications following routine cataract surgery under topical or sub-Tenon's anaesthesia.
Methods. A randomized double-blinded placebo-controlled clinical trial of 210 patients assigned to either a sub-Tenon's group (sub-Tenon's anaesthesia with placebo topical balanced salt solution, n=140) or a topical anaesthesia group (topical anaesthesia with placebo sub-Tenon's injection of balanced salt solution, n=70) was carried out. All patients underwent phacoemulsification with intraocular lens implantation. Patients in the sub-Tenon's group received a single injection (3 ml) of a combination of lidocaine 2% (2 ml) and bupivacaine 0.75% (1 ml), and four doses of topical placebo (balanced salt solution). Patients in the topical anaesthesia group received four doses of topical proxymethocaine 0.5% and a placebo sub-Tenon's injection (3 ml) of balanced salt solution. No intracameral injection of local anaesthetic was given. A 10-point visual analogue pain scale was used preoperatively and for postoperative pain assessment immediately after the operation and 30 min postoperatively. The intraoperative complications in the two groups were recorded.
Results. The mean pain score immediately after surgery was 2.42 (SD 2.2) in the sub-Tenon's group and 3.44 (2.3) in the topical anaesthesia group (P=0.0043). The mean pain score 30 min after surgery was 1.24 (1.7) in the sub-Tenon's group and 2.25 (2.2) in the topical anaesthesia group (P=0.0009).
Conclusions. Patients undergoing cataract surgery under topical anaesthesia experience more postoperative discomfort than patients receiving sub-Tenon's anaesthesia. Surgery-related complications were similar in both groups.

Spectral entropy measurement of patient responsiveness during propofol and remifentanil. A comparison with the bispectral index
A. L. G. Vanluchene, M. M. R. F. Struys, B. E. K. Heyse and E. P. Mortier
British Journal of Anaesthesia 2004;93(5):645-654

Background. We compared two spectral entropies, state entropy (SE) and response entropy (RE), based on the irregularity of the EEG, to measure loss of response to verbal command (LOR_verbal) and noxious stimulus (LOR_noxious) with the bispectral index (BIS) during propofol infusion with and without remifentanil.
Methods. Three groups of 20 patients received an effect-site controlled propofol infusion (Ce_PROP) starting at 1 µg ml^-1 and increased in steps of 0.5 µg ml^-1 at 4 min intervals. In addition, a remifentanil infusion was maintained at a group-dependent, fixed effect-site target concentration (Ce_REMI) (0, 2 or 4 ng ml^-1). The ability of BIS, SE or RE to predict LOR verbal and LOR noxious were compared with the changes in BIS, SE and RE using logistic regression, prediction probability (P K), and sensitivity/specificity.
Results. In all groups, BIS, SE and RE decreased with increasing Ce PROP. However, BIS decreased more smoothly than SE and RE at deeper levels of sedation. At LOR_verbal, BIS 50, SE₅₀ and RE₅₀ increased with increasing Ce REMI. BIS, SE and RE all detected LOR_verbal accurately but BIS performed better at 100% sensitivity. Sensitivity/specificity for detection of LOR_verbal decreased for all methods with increasing Ce_REMI. LOR_noxious was poorly described by all measures.
Conclusion. LOR_verbal was detected accurately by BIS, SE and RE except for 100% sensitivity, where BIS performed better. Though BIS, SE and RE were influenced by remifentanil during propofol administration, their ability to detect LOR_verbal remained accurate. None of the measures predicted LOR noxious.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Thirty percent of patients have moderate to severe pain 24 hr after ambulatory surgery: a survey of 5,703 patients
Brid McGrath, FARCSI, Hany Elgendy, MSc, Frances Chung, FRCPC, Damon Kamming, FRCA, Bruna Curti, RN and Shirley King, RN
Canadian Journal of Anesthesia 51:886-891 (2004)

Purpose: Postoperative pain is the commonest reason for delayed discharge and unanticipated hospital admission after ambulatory surgery. We investigated the severity of pain at 24 hr postoperatively and determined the most painful procedures. The need for further medical advice and clarity of postoperative analgesia instructions were also studied.
Methods: Five thousand seven hundred and three ambulatory surgical patients were telephoned 24 hr postoperatively. Patients graded their pain using the ten-point self-assessing verbal scale (0 = no pain, 10 = worst pain). Data were analyzed in two groups, those with moderate to severe pain (pain score 4–10) and those with no or mild pain (0–3).
Results: Thirty percent of patients (1,495/5,703) had moderate to severe pain. Microdiscectomy, laparoscopic cholecystectomy, shoulder surgery, elbow/hand surgery, ankle surgery, inguinal hernia repair, and knee surgery were identified as the procedures causing most pain at 24 hr. 13.2% of patients needed medical advice by telephone, 1.4% made an unplanned visit to a doctor while the rate of readmission to the hospital was 0.08%. Ninety-eight percent found postoperative instruction sheets and advice helpful. Eighty-eight percent of patients indicated that analgesic instructions were absolutely clear.
Conclusion: This study has identified the more painful common ambulatory surgical procedures which will allow take home analgesia to be tailored according to individual procedures. Further improvement in analgesic instructions may help in better pain management of ambulatory surgery patients.

Under "real world" conditions, desflurane increases drug cost without speeding discharge after short ambulatory anesthesia compared to isoflurane
Stephan K. W. Schwarz, MD PhD FRCPC, Noam N. Butterfield, PhD, Bernard A. MacLeod, MD FRCPC, Edward Y. Kim, BSc, Luigi G. Franciosi, MSc PhD and Craig R. Ries, MD FRCPC PhD
Canadian Journal of Anesthesia 51:892-898 (2004)

Purpose: To compare the measured "real world" perioperative drug cost and recovery associated with desflurane- and isoflurane-based anesthesia in short (less than one hour) ambulatory surgery.
Methods: We conducted a prospective, randomized, blinded trial with patients undergoing arthroscopic meniscectomy under general anesthesia. Following iv induction, patients received either isoflurane (group I; n = 25) or desflurane (group D; n = 20) for maintenance. The primary outcome variable was total perioperative drug cost per patient in Canadian dollars. Secondary outcome variables included volatile agent consumption and cost, adjuvant anesthetic and postanesthesia care unit (PACU) drug cost, readiness for PACU discharge, and incidence of adverse events.
Results: Total perioperative drug cost per patient was $14.58 ± 6.83 (mean ± standard deviation) for group I, and $21.47 ± 5.18 for group D (P < 0.001). Isoflurane consumption per patient was 6.0 ± 3.0 mL compared to 18.6 ± 7.7 mL for desflurane (P < 0.0001); corresponding costs were $0.83 ± 0.42 vs $7.61 ± 3.15 (P < 0.0001). There were no differences in adjuvant anesthetic or PACU drug cost. All but one patient from each group were deemed ready for PACU discharge at 15 min postoperatively (Aldrete score 9). One patient in group D experienced postoperative nausea. No other adverse events were noted.
Conclusions: Measured total perioperative drug cost for a short ambulatory procedure (less than one hour) under general anesthesia was higher when desflurane rather than isoflurane was used for maintenance, essentially due to volatile agent cost. Desflurane use did not translate into faster PACU discharge under "real world."

Sufentanil modifies the antibacterial activity of bupivacaine and ropivacaine
Zohreh Tamanai-Shacoori, PhD, Valliollah Shacoori, PhD, Jean-Marie Vo Van, MD, Jean-Claude Robert, PhD and Martine Bonnaure-Mallet, PhD
Canadian Journal of Anesthesia 51:911-914 (2004)

Purpose: The purpose of our study was to investigate the effect on the growth of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Enterococcus faecalis (E. faecalis) of bupivacaine at a final concentration of 0.77 mg·mL^-1, ropivacaine at 1.2 mg·mL^-1, and sufentanil at 0.38 and 0.5 µg·mL^-1 (alone or in combination with bupivacaine and ropivacaine).
Methods: The strains were diluted to approximately 3 x 10 4 cfu·mL^-1 in Mueller-Hinton broth. The anesthetics (0.5 mL) were incubated with the bacterial suspensions (0.5 mL) for 24 hr at 37°C.
Results: Bupivacaine inhibited the growth of E. coli (59 ± 0.8%; P < 0.05) and S. aureus (22 ± 3.6%; P < 0.05). Ropivacaine also inhibited the growth of E. coli (41 ± 1.2%; P < 0.05) and S. aureus (25.5 ± 4.1%; P < 0.05). Both anesthetics were ineffective against E. faecalis. Sufentanil only inhibited S. aureus (13.8 ± 3.1%; P < 0.05) at a concentration of 0.5 µg·mL^-1. Sufentanil modified the antibacterial activity of bupivacaine and ropivacaine. It increased the inhibitory effect of bupivacaine on E. faecalis and S. aureus by 10 ± 2.1% (P < 0.05) and on E. coli by 7% (P < 0.05). Sufentanil did not increase the inhibitory effect of ropivacaine on the growth of S. aureus. On the other hand, sufentanil reduced the inhibitory effect of ropivacaine on E. coli by 11% (P < 0.05).
Conclusion: Both bupivacaine and ropivacaine alone or combined with sufentanil inhibited the growth of E. coli and S. aureus. E. faecalis was partially sensitive to a bupivacaine + sufentanil mixture. Sufentanil had a partial synergistic effect on bupivacaine and a partial antagonistic effect on ropivacaines antibacterial activity.

PUB MED - TOP

Efficacy of bupivacaine for post-tonsillectomy pain: a study with the intra-individual design.
Somdas MA, Senturk M, Ketenci I, Erkorkmaz U, Unlu Y.
Int J Pediatr Otorhinolaryngol. 2004 Nov;68(11):1391-5

OBJECTIVE: To determine the effectiveness of postoperative local anesthesia in tonsillectomy patients using an intra-individual study design.
METHODS: Thirty patients aged 5-15 were included in a prospective study. Patients received a local infiltration of 0.5% bupivacaine solution on the right tonsillar bed, and received a local infiltration of normal saline on the left tonsillar bed. Patients were asked to localize pain in terms of most disturbing side of the pharynx, on the 1st, 4th, 8th, 16th, 24th hours.
RESULTS: Regarding pain over a 24-h period, there was a significant difference between two sides, after the 8th hour.
CONCLUSION: Postoperative local bupivacaine infiltration in tonsillectomy patients was effective in children.

Herbal medicine use by children presenting for ambulatory anesthesia and surgery.
Crowe S, Lyons B.
Paediatr Anaesth. 2004 Nov;14(11):916-9

Summary Background: Herbal medicine use has become increasingly popular throughout the world. Some of these agents may have serious interactions with anesthetic drugs. Children may potentially be more vulnerable to such interactions because of altered drug handling. While the prevalence of herbal medicine use by children with some chronic illnesses has been estimated, the incidence of this in a population of otherwise healthy children admitted for minor ambulatory anesthesia and surgery is currently unknown.
Methods: Parents of 601 children presenting consecutively for ambulatory surgery were asked to complete a questionnaire detailing administration of herbal medicines to their child.
Results: This study identified that 6.4% of children were currently taking an herbal preparation; while a further 10.1% had taken an herbal medicine in the past. Echinacea and arnica were the commonest used herbal remedies. A significant number of children had taken agents which may interact with anesthesia and surgery: St John's Wort, valerian, garlic and gingko. Information on herbal medicines was mostly obtained by parents from nonmedical sources.
Conclusions: A total of 16.6% of children had a current or past history of ingestion of herbal medicines. This finding may have implications for the perioperative management of children presenting for day-case surgery.

Oral dextromethorphan reduces perioperative analgesic administration in children undergoing tympanomastoid surgery.
Hasan RA, Kartush JM, Thomas JD, Sigler DL.
Otolaryngol Head Neck Surg. 2004 Nov;131(5):711-6

Objective: To determine whether oral dextromethorphan (1 mg/kg) given one hour prior to surgery decreases opioid administration in the perioperative period in children undergoing tympanomastoid surgery.
Methods: This was a prospective randomized double-blinded and placebo-controlled study in which 20 male and 18 female children (age 11.5 +/- 3.5 years) were enrolled. Nineteen children received dextromethorphan (DM), while the other 19 received placebos. Postoperative pain was assessed using a visual analogue scale and a pain score of >/=5 was treated with intravenous morphine sulfate. Patients were discharged home on oral oxycodone.
Results: The total doses of fentanyl administered during surgery were higher in the placebo group compared to the DM group (4.1 +/- 2 vs 2.6 +/- 1.4 microg/kg, P = 0.02) and the total doses of intravenous morphine administered in the postoperative period were also higher in the placebo group compared to the DM group (150 +/- 80 vs 73 +/- 56 microg/kg, P = 0.004). The placebo group had a higher pain score at the time of admission to the Day Surgery Unit (DSU) and a higher maximum pain score, compared to the DM group, during their combined stay in the Post-Anesthesia Care Unit and DSU (7.3 +/- 1.5 vs 3.1 +/- 2.6, P = 0.001).
Conclusions: Premedication with DM reduces the need for opioid administration in the perioperative period in children undergoing tympanomastoid surgery.

When to inject analgesic agents intra-articularly in anterior cruciate ligament reconstruction: before or after tourniquet releasing.
Guler G, Karaoglu S, Akin A, Dogru K, Demir L, Madenoglu H, Boyaci A.
Arthroscopy. 2004 Nov;20(9):918-21

PURPOSE: To evaluate 2 different applications of an intra-articular (IA) mixture composed of 40 mL 0.25% bupivacaine and 2 mg morphine in anterior cruciate ligament (ACL) reconstructions, before and after tourniquet release.
TYPE OF STUDY: Prospective, double-blind, randomized, clinical trial.
METHODS: Forty patients who underwent ACL reconstruction were prospectively randomized into 2 groups. Group 1 was injected with IA morphine with bupivacaine 10 minutes before tourniquet release. Group 2 was injected with IA morphine with bupivacaine injection after tourniquet release, after a 30-minute period of waiting with closed drainage. Visual analog scale scores were recorded at 10 and 30 minutes and at 1, 2, 4, 8, 12, and 24 hours after surgery. Detailed records were kept of the amount of analgesic drug required.
RESULTS: In pain scores, there was no difference between the 2 groups except for 30 minutes postoperatively (P = .005). The first analgesic requirement time was significantly lower in group 2 (P < .001) and the total amount of opioid used was lower in group 2 (P = .037) than those in group 1. There was no difference between the 2 groups in terms of operation time (P = .484), although there was a significant difference between groups in terms of tourniquet time (P = .024).
CONCLUSIONS: We conclude that IA analgesic injection after tourniquet release is more beneficial to obtain postoperative analgesia in ACL reconstructions than the same injection before tourniquet release.

Paradoxical reaction following intravenous midazolam premedication in pediatric patients - a randomized placebo controlled trial of ketamine for rapid tranquilization.
Golparvar M, Saghaei M, Sajedi P, Razavi SS.
Paediatr Anaesth. 2004 Nov;14(11):924-30

Summary Background: Paradoxical reactions to benzodiazepines include restlessness, violent behavior, physical assault, act of self-injury and need for restraints. These may occur at variable times after administration. This study was designed to determine the incidence of paradoxical reactions following intravenous midazolam premedication in pediatric patients and to compare the efficacy of extra doses of midazolam with low-dose intravenous ketamine to rapidly tranquillize them.
Methods: A total of 706 ASA I, II children scheduled for elective surgery were given intravenous midazolam premedication. Children who developed a paradoxical reaction were randomly divided into three equal groups to receive: (i) extra midazolam, (ii) ketamine, or (iii) placebo as the test drug for treatment of paradoxical reaction. Ease of rapid tranquillization and need for a rescue tranquillizer (i.e. ketamine; irrespective of patient group) were compared among the three groups.
Results: Twenty-four (3.4%) children developed paradoxical reaction after midazolam premedication. Those who received ketamine as the test drug responded rapidly to ketamine. But the responses of the other two groups to their test drug were poor and the majority of them required ketamine as rescue tranquillizer (six in midazolam, seven in placebo, but no patient in the ketamine group; P < 0.05).
Conclusions: The results of this study demonstrate that ketamine is an effective drug for the treatment of paradoxical reaction following intravenous midazolam premedication. The exact mechanisms of these reactions and how it is aborted by ketamine are not clear.

Effect of metoclopramide on pain on injection of propofol.
Fujii Y, Uemura A.
Anaesth Intensive Care. 2004 Oct;32(5):653-6

We undertook a randomized, double-blind, placebo-controlled study to examine the efficacy of metoclopramide at three different doses (2.5 mg, 5 mg, 10 mg) for reducing pain on injection of propofol in 100 patients scheduled for elective surgery. Patients received intravenously the study drug, with venous occlusion for one minute, followed by propofol 2 mg/kg into a dorsal hand vein. The incidence of pain was significantly less in patients receiving metoclopramide 5 mg (32%) or 10 mg (28%) than in patients receiving placebo (80%) (P<0.01). No difference between metoclopramide 2.5 mg and the placebo groups was found. We conclude that pretreatment of a dorsal hand vein with metoclopramide in a dose of 5 or 10 mg, with venous occlusion for one minute, effectively decreases the incidence of pain caused by propofol injection.
 

Pain during injection of propofol: the effect of prior administration of ephedrine.
Agarwal A, Dhiraaj S, Raza M, Singhal V, Gupta D, Ranjan R, Singh PK, Singh U.
Anaesth Intensive Care. 2004 Oct;32(5):657-60

Propofol causes pain on intravenous injection in 28 to 90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. In a randomized, double-blind, placebo-controlled trial, we compared the efficacy of ephedrine 30 microg/kg pretreatment to lignocaine 40 mg for prevention of propofol-induced pain. Ninety-three adult patients, ASA 1 and 2, undergoing elective laparoscopic cholecystectomy were randomly assigned to three groups of 31 each. Group 1 received normal saline, group 2 received lignocaine 2% (40 mg) and group 3 received 30 microg/kg ephedrine. All pretreatment drugs were made up to 2 ml. Pain at the time of propofol injection was assessed on a four-point scale: 0=no pain, 1 =mild pain, 2=moderate pain, and 3=severe pain. Twenty-seven patients (87%) of ephedrine pretreatment patients had pain during intravenous injection of propofol as compared to 24 (77%) in the normal saline group. In the lignocaine group, propofol-induced pain was observed in only 13 (42%) when compared with other study groups (P<0.05). Pretreatment with ephedrine 30 microg/kg did not attenuate pain associated with intravenous injection of propofol, nor did it improve haemodynamic stability during induction. However, pretreatment with 2% lignocaine (40 mg) was effective in attenuating propofol-associated pain.

Adjustment of anaesthesia depth using bispectral index prolongs seizure duration in electroconvulsive therapy.
Nishihara F, Saito S.
Anaesth Intensive Care. 2004 Oct;32(5):661-5

Electroconvulsive therapy (ECT) under propofol anaesthesia induces relatively shorter seizures compared to barbiturate anaesthesia. Since significant correlation between seizure duration and bispectral index (BIS) value immediately before electrical stimulus has been reported among patients, adjustment of anaesthesia depth as determined by BIS may be effective in obtaining a longer seizure length. In the present study, we examined this hypothesis in those patients whose muscular seizure duration was less than 40s. ECT was prescribed to 20 patients suffering from endogenous depression. General anaesthesia was induced with propofol 1 mg/kg. Succinylcholine chloride 1 mg/kg was then given. The efficacy of electrical stimulation was determined using a tourniquet technique, electromyogram, and electroencephalography. When a patient had a seizure less than 40s in their second ECT treatment, the subsequent treatment was modified such that the electrical stimulus was given after waiting for a higher BIS value (+10-20). Intensity of electrical stimulus and anaesthesia conditions were identical in the two treatments. All 20 patients had longer seizures as determined by the electromyogram and/or electroencephalography when the stimulus was delivered at the higher BIS value. Seizure duration measured by muscle movement was 31+/-5 s when the stimulus was delivered without waiting and 46+/-10 s when delivered after waiting. There was a significant difference in seizure duration between the two treatments (P<0.01). Waiting for a recovery in BIS value before electrical stimulation can prolong seizure duration.

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