Background and objective: Non-depolarizing neuromuscular blocking agents have a shorter duration of action on the diaphragm than on skeletal muscles. It was to be tested if this also held true for rapacuronium, a shortacting, amidosteroid non-depolarizing neuromuscular blocker, lately withdrawn from the market, using a novel technique for stimulating the diaphragm and assessing its function.

Methods: Anaesthesia was induced with propofol 2 mg kg−1 and remifentanil 1 μg kg−1, and the trachea was intubated after topical anaesthesia. Rapacuronium was given at a dose of 1.5 mg kg−1. The diaphragm was stimulated by cervical magnetic stimulation of the phrenic nerves (2 Tesla, single coil) and airway pressure responses were measured at the endotracheal tube connector. The neuromuscular effects at the adductor pollicis and orbicularis oculi muscles were measured by acceleromyography.

Results: Fifteen males and five females (ASA I and II; 27 ± 8 yr; 73 ± 13 kg; mean ± SD) were recruited. Median maximal relaxation was less (P < 0.01) for the diaphragm (89%) than for the adductor pollicis or orbicularis oculi muscles (each 100%). The time to 25% recovery was shorter for the diaphragm than for adductor pollicis or orbicularis oculi (7.5 ± 3.1 versus 14.1 ± 3.7 and 15.1 ± 3.5 min, respectively, P < 0.01). Recovery from 25 to 75% was identical for the diaphragm and adductor pollicis (9.4 ± 2.9 versus 9.1 ± 3.5 min), but longer for orbicularis oculi (13.4 ± 4.2 min, P < 0.01). The median recovery time to TOF0.8 was shorter for the diaphragm (23.9 min) than for the adductor pollicis or orbicularis oculi muscles (31.5 and 28.4 min, respectively; P < 0.05).

Conclusions: As with other non-depolarizing muscle relaxants, the duration of the clinical effect of rapacuronium was shorter for the diaphragm than for skeletal muscle. The recovery index was identical for the diaphragm and adductor pollicis.

Background and objective The effect of anaesthesia induced by intrathecal injection of 6.3% MgS04 or 4% lidocaine on intracellular electrolyte homeostasis in spinal cord neurones of a rat model was investigated. Methods Intracellular Ca2+, Mg2+, Na+ and K+ concentrations were determined at different times after intrathecal administration of NaCI (saline, a control group), MgS04 or lidocaine.

Results In both thoracic and lumbar spinal cord segments, Ca2+ concentrations rose significantly 30min and 2 h after 6.3% MgSO4 injection, and after 24 h were still significantly increased compared with the values obtained from the control group which were subjected to sham ‘anaesthesia’ by saline injection (172,121 and 108ngmg−1 protein vs. control 23ngmg−1 protein, respectively, in the thoracic segment and 222, 229 and 176ngmg−1 protein vs. control 43ngmg−1 protein, respectively, in the lumbar segment). Lidocaine injection also produced a significant increase in intracellular Ca2+ in the thoracic and lumbar spinal cord segments (69, 64 and 53ngmg−1 protein vs. control 33.4 ngmg−1 protein and 26, 94 and 46ngmg−1 protein vs. 23ngmg−1 protein respectively). Only a modest rise in intracellular Mg2+ was observed after intrathecal MgS04 or lidocaine injection (27ngmg−1 protein vs. 23ngmg−1 protein). Na+ and K+ concentrations decreased 24 h after MgS04and 1h after lidocaine injection.

Conclusion Intrathecal anaesthesia by MgS04 or lidocaine alters intracellular electrolyte homeostasis in spinal cord neurones of experimental rats. A possible common mechanism of action via Ca2+ ion channels is discussed.

This paper describes two otherwise unrelated cases of fatal haemopericardium resulting directly from attempted cannulation of the right subclavian vein. Although this is an extremely rare complication, it is essential that all physicians involved in establishing central venous access are aware of the danger of causing this condition, and how the use of a careful technique of insertion can minimize the risk.

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.

We report a case of post-operative rhabdomyolysis following transmandibular buccopharyngectomy without reconstruction in a patient remaining in the supine position throughout the procedure. Muscle compression induced by a cushion used during the procedure had probably contributed to the rhabdomyolysis. Outcome was favourable without acute renal failure. Prevention, early diagnosis and treatment are the keys to a successful recovery.

Summary

Background and objective: Isoflurane is a chiral volatile anaesthetic, routinely administered as racemate. It has a low metabolic rate and is mostly eliminated via respiration. In blood samples, S(+) enantiomers are found in greater proportion in the days immediately after administration of isoflurane racemate whereas the ratio in breath samples is unknown.

Methods: Breath and blood samples were drawn immediately after recovery and daily up to 19 days after operation from patients undergoing anaesthesia with isoflurane racemate. The percentage of isoflurane enantiomer was determined by gas chromatography mass spectrometry in blood and thermodesorption gas chromatography mass spectrometry in breath samples.

Results: In breath samples, there were significant differences in S(+) enantiomers at all time points compared to the racemate. During the early postoperative phase, the percentage of S(+) enantiomers were significantly enhanced whereas 5 days after surgery predominantly R(−) enantiomers (50.41%) were detected in the breath samples. Also in blood samples a statistical significant accumulation of the S(+) enantiomer was noted between days 1 and 5 compared to isoflurane racemate blood control. S(+) enantiomers were significantly higher in blood compared to breath samples and was most evident on the third day after surgery (51.43%).

Conclusions: During the first days after application of isoflurane racemate, the percentage of S(+) enantiomers are higher in breath and blood samples of patients. We suggest that resorbtion and/or redistribution of enantiomers are responsible for the different kinetics of isoflurane enantiomers.

Summary

Background and objective: We have investigated the toxic and teratogenic effects of certain non-depolarizing muscle relaxants on embryonic development in cultured rat embryos.

Methods: Rat embryos of 9.5 days were explanted and cultured in vitro for 48 h in rat serum. Whole rat serum was used as a culture medium for the control group while different concentrations of atracurium, cis-atracurium, rocuronium and mivacurium were added to rat serum for the experimental groups. Dose-dependent effects of these agents on embryonic developmental parameters were compared using morphological and biochemical methods. Each embryo was evaluated for the presence of any malformations.

Results: When compared to the control embryos, the muscle relaxants significantly decreased all growth and developmental parameters dose dependently with an increase in overall dismorphology. Among these malformations, maxillary deformity was most frequently observed. These effects were observed in much lower doses with atracurium and cis-atracurium compared to those with rocuronium and mivacurium.

Conclusions: Our results suggest that non-depolarizing muscle relaxants cause dose-dependent toxicity on rat embryos at concentrations much greater than those in clinical practice. Although, these agents seems to have a low potential for causing developmental toxicity during organogenesis, because of the lower toxic effects observed with rocuronium and mivacurium, these agents may be preferred when recurrent administrations are necessary for parturients.

In the past 10 years, the management of brain injury has shown several advances. Besides new diagnostic tools many new tentative approaches have been investigated, such as jugular bulb measurement of oxygen and lactate differences and near-infrared spectroscopy. The latest tool is microdialysis, which uses a probe as an interface to the brain. This method uses internally perfused semi-permeable membrane probes, which allow neurochemical water-soluble substances to be collected outside the brain for further analysis. Since the late 1980s the first results of microdialysis in neurointensive care show that chemical substances such as lactate, glucose, amino acids, metabolites of several biochemical mechanisms and electrolytes are measurable. This heterogeneous approach now waits for validation for clinical use and for the most challenging aspect, the clinical interpretation and use to improve therapy. The aim of this review is to describe the state of the art of this new technique, including our own experiences and concepts.

We have investigated the effects of midazolam and diazepam on intracellular calcium (Ca2+) handling in foetal mouse ventricular myocytes using the Ca2+-sensitive fluorescent indicator, indo-1. We also investigated separately whether flumazenil or the L-type Ca2+channel agonist, Bay K8644, antagonized these myocardial depressive effects. Midazolam and diazepam decreased the Ca2+transient and beating rate in a concentration-dependent manner, and these decreases were prevented by Bay K8644. Flumazenil did not antagonize the myocardial depressive effects. In myocytes whose sarcoplasmic reticulum was inhibited by ryanodine, midazolam and diazepam had the same potent cardiodepressive effects. Midazolam and diazepam are direct cardiac depressants, which decrease the Ca2+transient and beating rate, and the L-type Ca2+channel is important in the negative inotropism and chronotropism caused by these drugs.

Summary

Background: To evaluate the myocardial protective effect of nicorandil when used as an adjuvant to cold hyperkalaemic cardioplegia in open-heart surgery. Methods: Patients who underwent surgery under cardiopulmonary bypass (CPB) for mitral valve replacement (MVR, 23 patients) or coronary artery bypass grafting (CABG, 24 patients) were entered in a double-blind study. The patients were randomized to a nicorandil Group (N) or placebo Group (P). Nicorandil 0.1 mg kg−1 (Group N), or normal saline (Group P), were administered at three time points: (1) after aortic cannulation, but prior to going on CPB, (2) 5 min before aortic cross-clamping and (3) 5 min before reperfusion. The following variables were studied: (a) time until electromechanical arrest after cardioplegia administration (Tarrest), (b) time until return of electromechanical activity after aortic cross-clamp removal (Trecovery), (c) incidence of postoperative myocardial infarction or low output syndromes (d) dysrhythmias requiring intervention after aortic cross-clamp removal and (e) haemodynamic changes after nicorandil administration. Results: The Tarrest after cardioplegia administration was significantly faster in nicorandil group in both MVR and CABG patients (P < 0.05), but Trecovery did not differ significantly. The incidence of postoperative serum CK-MB > 75 IU L−1 in MVR patients was significantly lower in the Group N than in placebo patients (P < 0.05). However, in CABG patients there was no such significant difference. The incidence of dysrhythmias requiring intervention after aortic cross-clamp removal was also less in Group N. Administration of 0.1 mg kg−1 boluses of nicorandil did not cause significant haemodynamic changes or precipitate dysrhythmias in any patient. Conclusion: Nicorandil enhances the myocardial protective effect of cold hyperkalaemic cardioplegia in cardiac surgery patients.

Background and objective: The study was conducted to compare the standard intravenous route with the intranasal route of desmopressin application and to establish the best time for initiating treatment with desmopressin with the use of the Born test and the PFA 100®-Analyzer for monitoring the therapeutic effect.

Methods: Thirty healthy volunteers (ASA I) with no known bleeding disorder were randomly assigned to an intravenous or an intranasal group in a cross-over design fashion. After obtaining baseline values, the volunteers were given 500 mg aminosalicylic acid for 3 days. On day 4, platelet function tests were performed and desmopressin (0.3 μg kg−1 body weight) was administered either intravenously or intranasally. Born tests (aggregation after stimulation with epinephrine and collagen) were conducted at 30 and 240 min, and PFA 100® bleeding time measurements were conducted at 30, 120 and 240 min after desmopressin administration. Wilcoxon signed rank sum tests or non-parametric ANOVA for repeated measures were used for statistical evaluation.

Results: All volunteers showed a marked decreased platelet function in the Born test (especially if stimulation with epinephrine was used) and an increased PFA 100® bleeding time after treatment with aminosalicylic acid. Platelet function was improved by intravenous as well as intranasal application of desmopressin (P < 0.001) after 30 min. The effect diminished after 4 h in both groups.

Conclusions: Intravenous as well as intranasal desmopressin improved platelet function in healthy volunteers with aminosalicylic acid-induced platelet dysfunction at least 30 min after application. The effect lasts up to 4 h.