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This study was designed to measure total and free bupivacaine (B) after spinal anaesthesia in newborns and to evaluate a possible influence of adrenaline on B absorption. Twenty-two newborns were randomly allocated to receive either plain B (group 1) or adrenaline added to B (group 2) for spinal anaesthesia. A single blood sample was collected ten min after spinal injection. Total B concentration was found 0.31 +/- 0.17 microgram ml-1 in group 1 and 0.25 +/- 0.09 microgram ml-1 in group 2. Bound B concentration was 0.27 +/- 0.17 microgram ml-1 in group 1 and 0.22 +/- 0.09 microgram ml-1 in group 2. No difference was found between the two groups for these parameters. Albumin but not alpha 1-acid-glyco-protein correlated to age and weight, bound B correlated to alpha 1-acid-glyco-protein but not to albumin. Despite the low plasma concentration of binding proteins in newborns, spinal anaesthesia with B does not result in a high level of free drug. Adrenaline does not have any pharmacological advantage in these patients.

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Eight trials comparing the effects of vecuronium in patients with either normal renal function or renal failure were subjected to a meta-analysis. Vecuronium doses were similar in the different trials, identical in the two patient groups of any given trial, and ranged from 0.05 to 0.14 mg.kg-1. Neuromuscular blockade was assessed by TOF or single twitch stimulation, and recorded by either mechanomyography or electromyography. Indices of blockade included onset time (from injection to maximal twitch depression), duration of action (from injection to recovery to 25% of control twitch) and 25-75% recovery index. Statistical analysis used Hedges method: effect size and variance were calculated for each relevant outcome, then the global effect size was estimated by pooling the effect sizes of each trial. Three separate meta-analyses were conducted. No differences were found either in onset time, or in recovery index between the two groups, whereas the duration of action was longer in the renal failure group. It is concluded that renal function is likely involved in the pharmacokinetic parameters of vecuronium.

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This study investigated the efficacy of a constant rate infusion of propofol and fentanyl in thirty patients requiring artificial ventilation for more than 24 h. A loading dose, which differed according to the patient's age, was administered over a 30 min period: 2.5 mg.kg-1 for patients less than 50 (G1) (n = 9), 2 mg.kg-1 for patients between 50 and 60 years old (G2) (n = 9), and 1.5 mg.kg-1 for patients over 60 (G3) (n = 12). This was followed by an infusion of 3 mg.kg-1.h-1 in G1 and G2, and 2 mg.kg-1.h-1 in G3. A 1 microgram.kg-1.h-1 infusion of fentanyl was also given. The degree of sedation was assessed with the Ramsay scale before starting, after induction, and every four hours thereafter. When this proved to be insufficient, the dose of propofol was increased by 0.5 mg.kg-1.h-1 as well as that of fentanyl by 0.5 microgram.kg-1.h-1. Heart rate, mean arterial blood pressure, blood propofol, creatinine, transaminase and lipid levels, and urine output were measured before, during, and after the infusion. The blood propofol level increased during the infusion, being correlated to the doses given (r = 0.64, p less than 0.001). Sedation lasted 91.7 +/- 57.7 h. After stopping the infusion of propofol, mean recovery times were 7.5 +/- 5.9 min (G1), 11.4 +/- 11.4 min, and 14.4 +/- 13.5 min (G3) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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A case is reported of a 50-year-old man who took a massive overdose of diltiazem (5,400 mg), together with 1,350 mg potassium clorazepate and 390 mg nordazepate, five months after having experienced a myocardial infarction (MI). On admission, systolic blood pressure was 80 mmHg, with an irregular heart rate of 60 b.min-1. There was superficial polypnea (40 c.min-1) with hypoxia (PaO2: 63.5 mmHg). The ECG revealed, besides the MI scar, complete sinus arrest. Endotracheal intubation and mechanical ventilation were rapidly required. The patient then had gastric lavage, and was given activated charcoal. Treatment with 1.5 mg atropine and 2 g intravenous calcium chloride were unable to amend the cardiac dysrhythmia. A continuous isoproterenol infusion restored a sinus rhythm, but this was not maintained because of the risk of side-effects. Cardiovascular collapse was treated with dobutamine (10 micrograms.kg-1.min-1). As the peripheral and pulmonary vascular resistances were greatly diminished (464 dyn.s.cm-5 and 86 dyn.s.cm-5 respectively), alpha and beta mimetics were used: 1 microgram.kg-1.min-1 noradrenaline and 15 micrograms.kg-1.min-1 dobutamine. After 7 h of this treatment, spontaneous sinus rhythm returned abruptly. Noradrenaline and dobutamine were replaced thereafter with adrenaline (0.25 microgram.kg-1.min-1), which was stopped 24 h later. There was a marked respiratory and haemodynamic improvement, the patient leaving the intensive care unit on the fourth day and returning home one week after the overdose. The relationships between cellular calcium movements and the adrenergic system are discussed, as well as the possible mechanism of cardiac failure.

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The goal of this study was to assess the degree of postoperative anxiety flumazenil might provide in patients when used to reverse the sedation induced by midazolam. Twenty-four patients, aged 18 to 60 yrs, and scheduled for elective orthopaedic surgery of the upper limb, were included in the study Regional anaesthesia (brachial plexus block) was carried out 20 min after the patient had been premedicated with 0.15 mg.kg-1 intramuscular midazolam. When the block was clinically complete, 0.12 mg.kg-1 midazolam was given intravenously. Sedation was maintained throughout surgery using 0.03 mg.kg-1 midazolam every quarter of an hour (mean total dose 0.206 mg.kg-1). At the end of the procedure, the patients were randomly allocated to one of two groups: A+, the patients were given 0.1 mg intravenous flumazenil repeated every min until the patient was fully awake (mean 4.5 +/- 2.6 micrograms.kg-1); and A-, the patients were allowed to recover spontaneously. A wakefulness, and a determination just before premedication (E1, P1, H1 respectively). The degree of recovery was assessed in both groups, and, when the value of the wakefulness test had returned to that of E1 (E2) (E2 = E1), P2 and H2 were carried out. There were no statistically significant differences between P1 and P2, and between H1 and H2, and this for either group of patients. So, the doses of flumazenil used, which awoke all the patients within 3 min, did not create any anxiety. In accordance with most of the recently published studies, flumazenil can be safely used to reverse benzodiazepine induced sedation.

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A case is reported of a 56 year old woman admitted for status asthmaticus. She had no known history of cardiovascular disease. During the infusion of salbutamol, there appeared signs of myocardial infarction on the ECG trace. The patient did not complain of any symptoms suggestive of myocardial infarction. Closer cardiac examination and ultrasound revealed features of hypertrophic cardiomyopathy. The first ECG carried out on admission was in fact in favour of this diagnosis. The pathogenesis of this myocardial infarction is discussed: the long lasting hypoxaemia and the tachycardia induced by the salbutamol simulated hard exercise, poorly tolerated by patients suffering from hypertrophic cardiomyopathy. Also, this type of cardiomyopathy is known to be associated with impaired myocardial vasodilator reserve and small vessel coronary artery disease.

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