Are only large doses of rocuronium an alternative to succinylcholine for rapid-sequence induction?
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Biomedical subjects
Publications and source records attributed to G Mitterschiffthaler.
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The time-course of action and tracheal intubating conditions of rocuronium and succinylcholine under intravenous anesthesia with propofol, alfentanil, and nitrous oxide were studied in 30 patients undergoing outpatient surgery. The neuromuscular effects of both drugs were quantified by recording the indirectly evoked twitch response of the adductor pollicis muscle after ulnar nerve stimulation (0.1 Hz, 0.2 ms supramaximal stimuli). Patients were given either 0.6 mg/kg rocuronium (n = 20) or 1 mg/kg succinylcholine (n = 10) intravenously. Sixty seconds after the administration of the muscle relaxant, the trachea was intubated and the intubating conditions were scored by a "blinded" assessor. Intubating conditions were not different (P = 0.34) between the rocuronium and succinylcholine groups. The onset and duration of neuromuscular blockade were shorter with succinylcholine than with rocuronium. The depression of the twitch response to 5% of control value occurred in 0.8 +/- 0.1 min with 1 mg/kg succinylcholine and 1.2 +/- 0.5 min with 0.6 mg/kg rocuronium (P less than 0.01). The recovery of the twitch response to 25%, 75%, and 90% of its control value was shorter after succinylcholine (P less than 0.001) and occurred at 8.1 +/- 2.6, 10.3 +/- 3.9, 11.3 +/- 4.6 and 25.3 +/- 5.0, 33.1 +/- 5.9, 36.1 +/- 6.3 min after succinylcholine and rocuronium, respectively. Also the time required for spontaneous recovery from 25% to 75% of the control twitch response was significantly shorter (P less than 0.001) after succinylcholine (2.2 +/- 1.4 min) than after rocuronium (7.8 +/- 2.1 min). It is concluded that in spite of the pharmacodynamic differences between succinylcholine and rocuronium, the intubating conditions after administration of both compounds are similar and develop at the same rate.
421 severely injured patients admitted to a major trauma centre in Innsbruck during the ten years, 1981 to 1990, were investigated retrospectively for early prediction of survival by means of the Innsbruck Coma Scale (ICS). All 79 patients scoring 0 or 1 died within 21 days. The findings of this study indicate that the ICS allows a highly accurate prediction of non-survival in patients with scores of 0 or 1 even at the time of first examination after trauma.
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Acute thrombosis of an umbilical vein varix in combination with a single umbilical artery is a rare cause of fetal death. We now report such a case.
Because of the risk of ventilatory depression, agonistic and partially agonistic/antagonistic opiates are well suited for providing pain relief in obstetrics. We compared two groups of 20 women each with pregnancy on term who received equipotent doses of nalbuphin (0.1 mg/kg) and pethidin (0.8 mg/kg) intramuscularly. We found a significantly longer (6h) and better analgesic effect in the nalbuphin group but also a significantly more pronounced sedation. Other side effects were fewer in this last-named group. There were no differences in the behaviour of the babies between both groups. We consider that because of the "ceiling effect" of ventilatory depression, nalbuphin may allow better analgesia without the risk of ventilatory depression of both mother and newborn.
The time-course of action of 0.1 mg/kg vecuronium and 0.5 mg/kg atracurium was investigated in nonpregnant and in postpartum patients within 4 days after delivery. The clinical duration of vecuronium, but not that of atracurium, was significantly prolonged in the latter group (P less than 0.001) and averaged 36 +/- 6 and 37 +/- 4 min for atracurium and 32 +/- 6 and 49 +/- 10 min for vecuronium in nonpregnant and in postpartum patients, respectively (mean +/- SD). In additional in vitro experiments in the rat phrenic nerve-hemidiaphragm preparation no difference could be observed in the neuromuscular blocking effects of vecuronium in postpartum and nonpregnant female rats. It is concluded that pregnancy-induced changes in liver blood flow and/or competition for the liver uptake of sexual hormones might interfere with the hepatic clearance of vecuronium in postpartum patients and thereby cause the observed prolongation of neuromuscular blockade.
We investigated atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP) in patients undergoing elective direct current cardioversion (CV group) due to atrial fibrillation (n = 9) or atrial flutter (n = 3). Anesthesia for cardioversion (CV) was induced with propofol 1.5 mg/kg. Conversion was achieved in all patients. Before CV all patients had elevated ANP and cGMP plasma levels. After CV the concentrations of ANP and cGMP decreased significantly within 15 and 30 minutes (p less than 0.01), respectively. Only one patient in the CV group showed increasing ANP and cGMP levels although his heart rate had decreased after CV and his blood pressure remained stable. High concentrations of ANP and cGMP might possibly be a compensatory mechanism of cardiac dysfunction. To study the influence the anesthetic agent on plasma levels of ANP and cGMP, we investigated six patients anesthetized with propofol for high-density radiation (HDR group). The data from this control group showed that propofol did not influence the plasma levels of ANP and cGMP. ANP correlated statistically significantly (p less than 0.05) with cGMP in both groups (r = 0.88 and 0.76 in the HDR and CV groups, respectively). In addition, we found a cGMP release of 149.6 +/- 17.6 per mol ANP in the HDR group, in the CV group the release was 109 +/- 54.2 cGMP per mol ANP. This phenomenon could be due to minor response of target cells to ANP stimulation (receptor down-regulation) in patients with heart disease. In conclusion, ANP and cGMP levels decreased after successful cardioversion.(ABSTRACT TRUNCATED AT 250 WORDS)
The time-course of the neuromuscular effects of vecuronium (n = 25) and atracurium (n = 25) has been compared at three different levels of maintenance dose in anaesthetized patients. Following intubation with vecuronium 0.1 mg kg-1 or atracurium 0.5 mg kg-1, surgical muscle relaxation was maintained by using increments of equipotent maintenance doses equivalent to 0.5, 1.0 and 1.5 x ED95 for each drug. Repeat doses were administered each time the twitch height, depressed by the previous dose, returned to 25% of its control value. The apparent increase in the duration of action, i.e. the difference between the duration of the last and the first maintenance dose, did not reach statistical significance and approximated 3 +/- 2, 6 +/- 4, 11 +/- 5 and 3 +/- 2, 8 +/- 13, 5 +/- 7 min following the low, medium and high maintenance doses of vecuronium and atracurium, respectively.
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Beta-endorphins are substances produced by the body to inhibit the perception of pain. Normally they exhibit a steep rise during birth. We have seen an impressive fall which also was statistically highly significant after the application of transcutaneous electric nerve stimulation in 20 parturient women.
We investigated 69 patients (most belonging to NYHA classes II and III) undergoing elective direct current cardioversion of atrial fibrillation (46 patients) and atrial flutter (23 patients), respectively. Without premedication anaesthesia was induced with the new soya bean emulsion of propofol ('Diprivan') 1.2 mg.kg-1 over 45 s. Recovery time was measured from the start of the anaesthetic injection to the moment at which the patients regained consciousness. Completeness of recovery was assessed with two methods: opening eyes on command and time orientation. Good amnesia was observed in all patients. Conversion was achieved in all but seven patients (90%). After injection of propofol, the mean arterial pressure decreased slightly (2% below baseline). Induction of anaesthesia and successful DCC effected a statistically significant decrease in both the heart rate and the rate pressure product. Eleven patients required assisted ventilation for 2 min due to respiratory depression. Fifteen patients developed arrhythmias. Side-effects, such as myocloni, recall or vomiting, were not observed. In conclusion, propofol may well prove to be the anaesthetic of choice for DCC in cardiac patients because of good amnesia, low incidence of side-effects and short recovery time (mean 5.3 min).
We assessed the efficacy of subcutaneous administration of flumazenil (Anexate, Roche), a specific benzodiazepine antagonist, in preventing resedation after initial reversal of midazolam sedation in 30 patients (ASA I-II) undergoing gynaecological surgery. In the post-operative period, the patients received flumazenil i.v. and placebo s.c. (group A), flumazenil i.v. and flumazenil s.c. (group B), or placebo i.v. and placebo s.c. (control group) in a randomized, double-blind procedure. Flumazenil (group A: 0.47 (SD 0.12) mg i.v., group B: 0.48 (0.06) mg i.v.) was significantly more effective than placebo in antagonizing the sedative effects of midazolam, but was accompanied by rebound sedation after 90 min. Additional s.c. administration of flumazenil 0.1 mg (group B) did not eliminate resedation. Undesirable side effects include nausea and vomiting. Local tolerance of the subcutaneous administration of flumazenil was good.
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Although alcuronium has been in clinical use for almost 40 years, there is still considerable controversy in the literature regarding its neuromuscular blocking potency, the time course of the drug action and the side effects. The aim of this study was to investigate the dose-response relationship of alcuronium and to compare the time course of its neuromuscular effects with vecuronium following intubation doses of both compounds. METHODS. The study was carried out in two parts. In the first part 60 patients and in the second part 30 consenting ASA class I or II patients 20-60 years of age were included. The patients were undergoing elective gynecological or intra-abdominal operations. In the first part the patients received six different doses of alcuronium (60, 90, 120, 150, 180 or 210 micrograms/kg) in order to establish its dose-response relationship. Each dose was administered to ten patients. In the second part patients received either 300 micrograms/kg alcuronium (n = 15) or 100 micrograms/kg vecuronium (n = 15), and the time course of these two compounds (onset time, duration 25%, duration 75% and the recovery index) were compared. To test the reversibility, ten patients in each group received 30 micrograms/kg neostigmine at 25% recovery of T1. The neuromuscular effects of alcuronium and vecuronium were quantitated by EMG using the DATEX relaxograph. RESULTS. The log-logit analysis of the dose response data revealed an ED50 of 111 micrograms/kg and an ED95 of 250 micrograms/kg, which is in reasonable agreement with the measured effects following 120 micrograms/kg and 210 micrograms/kg alcuronium, resulting in 52 +/- 21% and 96 +/- 4% T1 depression, respectively. The onset time, duration 25%, duration 75% and spontaneous recovery index following 300 micrograms/kg alcuronium (5.0 +/- 3.4 min, 62 +/- 25 min, 119 +/- 38 min and 58 +/- 34 min) appeared to be significantly longer (P less than 0.05) than those observed after 100 micrograms/kg vecuronium (3.2 +/- 1.2 min, 33 +/- 7 min, 49 +/- 9 min and 18 +/- 7 min), respectively. The most striking finding of this study is the enormous individual variations observed in both neuromuscular potency and the time course of action of alcuronium. Following 150 micrograms/kg (routinely employed in daily clinical practice), the magnitude of T1 depression ranged between 19% and 100%. The same vast individual variations were observed in the time course of action following 300 micrograms/kg of alcuronium. The onset time, duration 25%, duration 75% and spontaneous recovery index ranged between 1.3 and 14 min, 22 and 110 min, 93 and 186 min and 32 and 116 min, respectively. CONCLUSIONS. The ED50 and ED95 values for alcuronium found in this study are in the same order of magnitude as 106.8 micrograms/kg and 135 micrograms/kg for ED50 and with 280 micrograms/kg for ED95, respectively, as reported by others. The long duration with slow recovery and the wide individual variation in the neuromuscular effects observed in our study have been reported earlier. Based on the above observations and because of the availability of better alternatives with fewer side effects, we conclude that alcuronium should be added to the list of obsolete neuromuscular blocking agents, together with gallamine and d-tubocurarine.