Summary

Background and objective: The amide-linked local anaesthetics, bupivacaine and ropivacaine, can cause depression of cardiac contractility and dysrhythmias. In a previous study, we observed decreased contractility and ST segment depression following ropivacaine administration in anaesthetized dogs. The efficacy of intravenous (i.v.) and intracoronary nicorandil (30 and 100 μg kg−1), i.v. nitroglycerin (glyceryl trinitrate) (5 μg kg−1) and calcium chloride (1, 2 and 4 mmol) in reversing the cardiotoxic effects of intracoronary ropivacaine were studied following the administration of intracoronary ropivacaine.

Methods: Six dogs were studied. The dogs were anaesthetized with i.v. pentobarbital (30 mg kg−1). A left-sided thoracotomy was performed and the left circumflex coronary was cannulated. For each dog, the dose of ropivacaine was identified, which produced measurable cardiotoxicity. In each case, ropivacaine was followed by one of the three resuscitation drugs. The effects of each resuscitation drug on ST segments and left ventricular contractility (dP/dt) produced by ropivacaine alone were compared with those produced by ropivacaine followed by each of the three resuscitation drugs using Fisher's exact test.

Results: The doses of ropivacaine required to produce depression of left ventricular dP/dt and ST segments ranged from 1 to 8 mg. Ropivacaine-induced depression of left ventricular contractility (dP/dt) was more rapidly and completely reversed by calcium chloride than by either nitroglycerin or nicorandil (P = 0.008).

Conclusions: Calcium chloride may be effective in the treatment of inadvertent intravascular administration of amide local anaesthetic agents.

Summary

Background and objective: Desflurane has been shown to increase sympathetic activity and heart rate (HR) in a concentration-dependent manner. Nevertheless, desflurane, like all other volatile anaesthetics, increased HR in parallel to vagal inhibition in a previous study. Therefore, our hypothesis is that desflurane elicits tachycardia by vagal inhibition rather than by activation of the sympathetic nervous system.

Methods: Six dogs were studied awake and during desflurane anaesthesia (1 and 2 MAC) alone, after pre-treatment with propranolol (2 mg kg−1 followed by 1 mg kg−1 h−1), or after pre-treatment with atropine (0.1 mg kg−1 followed by 0.05 mg kg−1 h−1). The effects on HR and HR variability were compared by an analysis of variance (P < 0.05). HR variability was analysed in the frequency domain as power in the high-(0.15–0.5 Hz, vagal activity) and low-frequency range (0.04–0.15 Hz, sympathetic and vagal activity).

Results: HR increased during 2 MAC of desflurane from about 60 (awake) to 118 ± 2 beats min−1 (mean ± SEM) in controls and to 106 ± 3 beats min−1 in dogs pre-treated with propranolol. In contrast, pre-treatment with atropine increased HR from 64 ± 2 to 147 ± 5 beats min−1 (awake) and HR decreased to 120 ± 5 beats min−1 after adding desflurane. High-frequency power correlated inversely with HR (r2 = 0.95/0.93) during desflurane alone and in the presence of β-adrenoceptor blockade, with no significant difference between regression lines. There was no correlation between these variables during atropine/desflurane.

Conclusions: The increase in HR elicited by desflurane mainly results from vagal inhibition and not from sympathetic activation.

Summary

Background and objective: Endogenous catecholamines are released in brain-dead organ donors following painful stimulation during retrieval surgery, and might be harmful to harvested organs. Our hypothesis was that inhibition of pain by fentanyl would inhibit such catecholamine release.

Methods: We tested 17 brain-dead organ donors in a randomized, placebo-controlled, double-blinded study. Blood samples for determination of epinephrine and norepinephrine concentrations were obtained before and 10 min after in take of either fentanyl 7 μg kg−1 or an equivalent volume of placebo. Further points of measurement were taken after skin incision and sternotomy. Mean arterial pressure and heart rate at these points were recorded.

Results: Catecholamine concentrations rose following painful stimuli. No differences in haemodynamics, between the fentanyl and the placebo group were detectable. Epinephrine concentrations, but not those of norepinephrine, were higher in the fentanyl group, reaching significance following sternotomy.

Conclusion: We conclude that the use of fentanyl (7 μg kg−1) was not effective in suppressing the catecholamine release, following painful surgical stimulation in brain-dead organ donors.

Summary

Background and objective: Inflammation promotes hyperalgesia and increases opioid binding protein (α1-acid glycoprotein) inducing increased opioid requirement. To investigate the influence of an acute episode of inflammatory bowel disease in opioid requirement during major abdominal surgery, 17 patients with Crohn's disease, 12 patients with ulcerative colitis and seven patients without any inflammatory process (control group) were prospectively studied. Sufentanil requirements were assessed during surgery.

Methods: Sufentanil administration was adjusted when haemodynamic variables changed more than 20% of preoperative values. In a subgroup of 20 patients (Crohn's disease: 7, ulcerative colitis: 7, control group: 6), plasma concentrations of α1-acid glycoprotein and unbound sufentanil were measured. Total plasma clearance of sufentanil was also determined. Data presented as median (25–75‰) were analysed by non-parametric and ANOVA tests.

Results: Despite similar surgery duration, intraoperative sufentanil requirements were significantly larger in both the Crohn's disease group (0.9 (0.6–1.6) μg kg−1 h−1) and the ulcerative colitis group (1.1 (0.6–1.7) μg kg−1 h−1) than in the control group (0.5 (0.4–0.5) μg kg−1 h−1). Total plasma clearance of sufentanil was larger in patients with inflammatory bowel disease than in the control group. The plasma α1-acid glycoprotein concentration was increased in the inflammatory bowel disease group. However, the free fraction of sufentanil was similar in all three groups. The largest sufentanil consumption in patients with inflammatory bowel disease was observed during time of pain stimulation in the area of referred hyperalgesia from the affected viscus. In the control group, the sufentanil requirement was constant throughout surgery.

Conclusion: Inflammatory bowel disease increases opioid requirement during major abdominal surgery.

Summary

Background: In this prospective randomized study we tested the hypothesis that use of more cyclo-oxygenase 2 (COX 2)-selective non-steroidal anti-inflammatory drugs (NSAIDs) can reduce perioperative blood loss compared with non-selective NSAIDs.

Methods: Data from 200 patients who underwent total hip replacement were studied. Two NSAIDs were compared: indomethacin 50 mg (n = 82) and meloxicam 15 mg (n = 86). Both NSAIDs were given orally 1 h before surgery.

Results: The two groups were not different with respect to age, gender, ASA class or duration of surgery. When indomethacin was used preoperatively, intraoperative blood loss was 623 ± 243 mL (mean ± SD) and postoperative blood loss 410 ± 340 mL. After meloxicam, these values were 524 ± 304 mL and 358 ± 272 mL, respectively. Total perioperative blood loss after meloxicam was 17% (P < 0.05) less than that observed after indomethacin.

Conclusion: Perioperative blood loss after meloxicam is less than after indomethacin. These in vivo findings are consistent with in vitro results using selective COX 2 NSAIDs.

Summary

Background and objective: This paper describes the user acceptance of an anaesthesia information management system at the University Hospital in Giessen, Germany, after 5 yr of routine use.

Methods: A questionnaire with 75 items was distributed to all anaesthesiologists and anaesthetic nurses of the Department of Anaesthesiology. The questions were answered anonymously on a five-point Likert scale.

Results: The return rate was 60% (44 physicians and 24 nurses). The results indicated that the system generally met user expectations. The respondents thought that electronic record keeping improved the quality of their work, and they did not want to switch back to paper records. Problems arose with hardware placement and software features, e.g. coding tools for diagnoses and type of surgery. The perceived quality of training strongly influenced user acceptance.

Conclusions: Despite the deficits revealed by the survey, the respondents did not want to switch back to manual record keeping. A structured user survey is a useful tool for the development, adaptation and implementation of an anaesthesia information management system. A training strategy that takes the needs of the users into account is recommended.

Summary

Background and objective: We compared the effects of sub-Tenon's local anaesthetic block and placebo on perioperative opioid requirement and cardiovascular stability and on postoperative pain, nausea and vomiting in patients undergoing vitreo-retinal surgery under general anaesthesia.

Methods: We studied 43 patients undergoing vitreo-retinal surgery under general anaesthesia in a randomized double blind study. Patients received a standard general anaesthetic followed by a sub-Tenon's injection of 4–5 mL of either bupivacaine 0.75% or saline. We recorded intraoperative invasive arterial pressure, then the incidence and severity of pain and of nausea and vomiting, for 24 h postoperatively.

Results: In the sub-Tenon's bupivacaine group, there was a significant reduction in the perioperative opioid use and a reduction in the frequency of bradycardia and hypertensive episodes, defined as a rise >25% of baseline for a duration of >3 min. The sub-Tenon's bupivacaine group also had significantly lower pain scores and nausea scores at 12 h, concomitant with a lower consumption of analgesia and antiemetics.

Conclusions: This local anaesthetic technique is effective in vitreo-retinal surgery and can be safely applied to this population of patients regardless of axial length.

Summary

Background and objective: This prospective, randomized, observer-blinded study compared onset time and duration of epidural anaesthesia produced by with levobupivacaine and ropivacaine for lower limb surgery.

Methods: ASA I–III adult patients undergoing elective lower limb procedures were randomized to receive epidural levobupivacaine 0.5% 15 mL (n = 30) or epidural ropivacaine 0.75% 15 mL (n = 35). A blinded observer evaluated onset time and regression of motor and sensory block, and intraoperative needs for fentanyl supplementation (0.1 mg intravenously).

Results: With levobupivacaine, onset time was 29 ± 24 min, with ropivacaine it was 25 ± 22 min (P = 0.41). Complete resolution of motor block required 105 ± 63 min with levobupivacaine and 95 ± 48 min with ropivacaine (P = 0.86). The time for regression of sensory block to T12 was 185 ± 77 min with levobupivacaine and 201 ± 75 min with ropivacaine (P = 0.46). Analgesic supplementation was required in one patient receiving levobupivacaine (3.5%) and in two patients receiving ropivacaine (5.7%) (P = 0.99).

Conclusions: In adults undergoing lower limb surgery, levobupivacaine 0.5% 15 mL produces an epidural block with the same clinical profile as ropivacaine 0.75% 15 mL.