Summary

Background and objective: Levobupivacaine is the most recently introduced local anaesthetic into clinical practice. In a randomized double-blinded study, the onset, intraoperative tolerance, postoperative analgesic effect, motor blockade and any adverse reactions produced by levobupivacaine were compared with ropivacaine.

Methods: Sixty children, ASA I–II, 2–6 yr old, undergoing elective minor surgery, received a single caudal injection of 1 mL kg−1 of either levobupivacaine 0.25% or ropivacaine 0.25%. Caudal blocks were performed after induction of inhalation general anaesthesia using sevoflurane; anaesthesia was maintained via a laryngeal mask airway using a mixture of sevoflurane, oxygen and air.

Results: Onset time, intraoperative tolerance, postoperative analgesic effect and motor blockade were comparable between the two groups. The mean onset of the block was 8.2 ± 2.2 min for levobupivacaine and 8.5 ± 3.0 min for ropivacaine (P = 0.66). Additional analgesics during operation were not required in any of the children. No significant difference was found for mean time to requirement of additional analgesia with rectal acetaminophen (paracetamol) (302 ± 29 min for the levobupivacaine group and 230 ± 38 min for the ropivacaine group (P = 0.32)). During the first 4 h after placement of caudal block, the pain assessment score (according to the Children Hospital Eastern Ontario Pain Scale) was comparable for the two groups. No motor block was observed in any group on awakening, nor during the observation period.

Conclusions: We conclude that levobupivacaine 0.25% 1 mL kg−1 provides caudal block of comparable onset and duration, as produced by the same volume and concentration of ropivacaine.

Summary

Background and objective: We studied the effect of different recumbent positions (supine, left and right lateral decubitus), on arterial oxygenation in 42 valvular heart disease patients planned for cardiac surgery. All patients had cardiomegaly (cardiothoracic ratio ≥0.5) in their chest X-rays. Their left ventricular end-diastolic diameter was also noted from the preoperative echocardiogram. Methods: Arterial blood gas analysis was performed in supine, left and right lateral positions after keeping the patient in a given position for 15 min. During this period all patients received 35% oxygen supplementation. Results: Arterial oxygen tension and haemoglobin saturation were significantly higher in the right lateral position (PaO2 = 120.6 ± 29.5 mmHg, SaO2 = 98.1 ± 1.4%) than in supine (PaO2 = 111.0 ± 30.6 mmHg, SaO2 = 97.6 ± 2.2%) and left lateral positions (PaO2 = 109.7 ± 32.0 mmHg, SaO2 = 97.6 ± 1.7%; mean ± SD; P < 0.01). There was no significant difference in arterial oxygenation between left lateral and supine positions (P > 0.05). The change in PaO2 and SaO2 with change of posture from left to right was significantly related to left ventricular end-diastolic diameter (r = 0.50 and r = 0.63, respectively; Pearson correlation). Repeated measures of analysis of variance with left ventricular end-diastolic diameter as a covariate showed a significant change in arterial PaO2 with posture (P = 0.011). Conclusion: Right lateral posture improves arterial oxygenation in the valvular heart disease patient with an enlarged left ventricle. In the preoperative period, these patients may benefit from a right lateral posture when lying in bed.

The dose-response and concentration-response relation of rocuronium infusion was studied in 20 adult surgical patients during propofol-nitrous oxide and isoflurane (1 MAC) -nitrous oxide anaesthesia. Neuromuscular block was kept constant, initially at 90% and then at 50% with a closed-loop feedback controller. At 90% block the steady-state infusion of rocuronium was 0.55 ± 0.16 mg kg−1 h−1 and the corresponding concentration 1714 ± 281 ng mL−1 in patients receiving propofol. At 50% block the corresponding infusion rate was 0.27 ± 0.11 mg kg−1 h−1 and the concentration 1077 ± 244 ng mL−1, respectively. At 50% block isoflurane reduced the rate of infusion by 52% (P < 0.005) and the concentration by 59% (P < 0.001); at 90% block both the mean infusion rate and the concentration of rocuronium were reduced by 35% (P <0.005). The mean rocuronium clearance at 50% block was unaffected by the type of anaesthesia; it was 4.1 ± 1.6 and 4.9 ± 2.7 mL kg−1 min−1 in the groups receiving propofol and isoflurane anaesthesia, respectively. We conclude that isoflurane reduces the infusion requirements of rocuronium by changing the pharmacodynamic behaviour.

The intra-operative management of two patients with chronic obstructive pulmonary disease and cardiovascular pathology, who underwent peripheral reconstructive vascular surgery under continuous spinal anaesthesia, is described. Furthermore, continuous intrathecal analgesia was also continued in the post-operative period and provided effective pain relief that was reflected by the favourable surgical outcome.

Anaesthetic agents have been implicated in the development of postoperative pneumonia, but the direct effect of volatile anaesthetics on bacterial growth has given contradictory results. The effects of isoflurane on the growth of Staphylococcus aureus and Escherichia coli were investigated under conditions similar to those of clinical practice, using standardized microbiological methods. An open anaesthetic circuit was adjusted to the normal ventilatory settings of an adult patient. A spray, installed on the inspiratory side of the circuit, ensured the delivery of isoflurane at 1.5 minimal alveolar concentration. The bacterial strains studied were both wild-type and reference strains. Bacterial inoculums were prepared to obtain a bacterial exponential growth of 103 colony-forming units per mL in 10mL of nutritive broth. Each strain was studied with and without exposure to isoflurane and measured by the usual criteria of bacterial growth, and by bacterial regrowth after exposure to isoflurane. Under experimental conditions close to clinical practice, exposure to isoflurane did not alter bacterial growth of S aureus and E. coli, or their bacterial regrowth when isoflurane exposure is over.

Complication during a drum catheter placement via an antecubital fossa vein is presented.

Summary

Background and objective: Acute hiccup is a minor complication that can occur during sedation or general anaesthesia. The disorder can disturb the surgical field, might interfere with lung ventilation or could hamper diagnostic procedures. The objective was to perform a systematic search for interventions aimed at treating hiccup occurring during anaesthesia or sedation.

Methods: A systematic search for reports describing interventions to treat hiccup in conjunction with anaesthesia was carried out (MEDLINE, EMBASE, Cochrane-Library, manual screening of reference lists and review articles, up to December 2001). Search terms were ‘hiccup’, ‘singultus’ or ‘hiccough’.

Results: Twenty-six reports involving approximately 581 patients focused on hiccup remedies in the anaesthesia setting. Only one report was substantiated by a randomized controlled trial. This investigated methylphenidate 10 mg intravenously in 51 patients, which did not show a beneficial effect compared with placebo. Hiccup was a self-limiting phenomenon. Case series and case reports focused on various systemically applied drugs in 12 reports, stimulating techniques (e.g. pharyngeal stimulation) in seven, topical applied remedies (e.g. intranasal ice-cold water) in four, and ventilation techniques (e.g. continuous positive pressure ventilation) in two.

Conclusions: A large variety of interventions have been proposed for the treatment of hiccup during anaesthesia and sedation. However, perioperative treatment is still based on empirical findings and no treatment is ‘evidence-based’. Thus, no valid recommendations for the treatment of hiccup can be derived. Uncontrolled observations are inadequate to establish treatment efficacy.

Background and objective: It was previously reported that topical ketamine inhibits albumin extravasation in a rat chemical peritonitis model. Using the same model, the present study investigated whether intravenous ketamine inhibited this extravasation.

Methods: Twenty-four rats anaesthetized with pentobarbital (75 mg kg−1) were randomly assigned to two groups: ketamine and a 0.9% NaCl (saline) group (n = 12 each). Ketamine 1% or saline 0.1 mL kg−1 min−1 was given intravenously for 60 min to the respective group. After the abdomen had been opened, peritonitis was elicited by topically applying a filter paper containing 0.02 M HCl 0.07 mL onto the surface of the appendix or caecum for 5 min. Fifteen minutes after removal of the filter paper, Evans' blue dye (50 mg kg−1) was injected intravenously. The extravasated dye was colorimetrically quantified by a spectrophotometer at 620 nm.

Results: The infusion of ketamine significantly reduced Evans' blue extravasation: 5.26 (range 4.18–6.34) μg per 100 mg tissue compared with the saline group control: 6.81 (5.93−7.69) μg per 100 mg tissue (P < 0.05).

Conclusions: It is suggested that ketamine anaesthesia may reduce albumin extravasation in inflammatory tissues.