Biomedical subjects
Publications and source records attributed to B Bryssine.
We describe a 25 mg intrathecal morphine overdose during a combined spinal-epidural block for a Caesarean delivery. Naloxone infusion (5.24 mg over 24 h) was started prior to the patient becoming symptomatic and almost immediately after the overdose. Invasive therapeutics such as mechanical ventilation were avoided.
In this double-blind, randomized, parallel group study, we have investigated the antiemetic activity of the potent and selective NK1 receptor antagonist GR205171 25 mg i.v. compared with placebo in the treatment of established postoperative nausea and vomiting (PONV) in patients after major gynaecological surgery performed under general anaesthesia. The incidence of PONV in the study population was 65%. Thirty-six patients were treated with placebo or GR205171 (18 patients per group). GR205171 produced greater control of PONV than placebo over the 24-h assessment period. The stimuli for emesis after PONV are multifactorial and the efficacy of GR205171 in this study supports the broad spectrum potential for NK1 receptor antagonists in the management of postoperative emesis. GR205171 was well tolerated and no adverse events were reported that would preclude the further development of this agent.
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OBJECTIVE: To assess physiological changes and operating conditions during general anaesthesia with or without neuromuscular blockade in patients undergoing gynaecologic laparoscopy. STUDY DESIGN: Prospective, randomized, double-blind study. PATIENTS: Fifty non-obese patients, mean age 31 years, randomly allocated into either a group of 25 with curare (AC) or a group of 25 without curare (SC). METHODS: All patients were anaesthetized with propofol (2.5 mg.kg-1), sufentanil (0.4 microgram.kg-1) midazolam (2 mg) and N2O-O2. In addition, those of the AC group were given atracurium 0.25 mg.kg-1 for intubation, followed by additional boluses to maintain twitch height < 10% of the control value. Blood pressure, heart rate, peak airway pressure, end-tidal carbon dioxide pressure were recorded before and during pneumoperitoneum maintained at a pressure of 15 mmHg. Operating conditions were assessed at 10-min intervals, using a four point scale. RESULTS: In both groups, blood pressure and heart rate decreased following induction. The decrease in blood pressure was more important in the SC group at 5 min and before pneumoperitoneum (25 vs 15%); P < 0.05). The time course of PETCO2 and peak airway pressures were similar between groups. Operating conditions were not influenced by the muscle relaxant. CONCLUSIONS: Neuromuscular blockade influences neither most of the clinical haemodynamic and respiratory changes induced by pneumoperitoneum for gynaecologic laparoscopy not the operating conditions.
We have studied the effects of volatile anaesthetics on lower oesophageal sphincter (LOS) tone in three groups of eight pigs allocated randomly to receive end-tidal concentrations of 0.5, 1.0 and 1.5 MAC of desflurane, isoflurane or halothane for 15 min. LOS and oesophageal barrier pressures (BrP = LOSP - gastric pressure) were measured using a manometric method. The decrease in BrP paralleled the decrease in LOS pressure and was significant at 0.5 MAC for isoflurane and at 1.0 MAC for halothane. At 1.5 MAC, BrP values were approximately 62% of baseline values for halothane, 37% for isoflurane and 83% for desflurane. Inter-group comparisons showed that BrP did not differ at baseline and at 0.5 MAC. At 1.0 MAC the effect of isoflurane on BrP was significantly different from desflurane (P < 0.001) and halothane (P < 0.02) whereas the effect of desflurane on BrP was not significantly different from halothane. At 1.5 MAC the effect of isoflurane on BrP was significantly different from desflurane (P < 0.01) and halothane (P < 0.05) whereas the effect of desflurane on BrP was not significantly different from halothane. We conclude that desflurane maintained BrP and this may be clinically important in patients at high risk of regurgitation.
BACKGROUND: For induction of anaesthesia, drugs such as propofol are commonly administered according to a per weight basis. However, drugs are primarily distributed to the fat-free mass. This study was undertaken to determine the relationship between propofol requirement for induction and body mass determined by bioimpedance analysis (BIA) or by body mass index (BMI). METHODS: Twenty-one ASA 1 female patients scheduled for gynaecologic surgery received propofol for induction at 133 mg.min-1. Stepwise regression analysis was used to describe the relationships between propofol requirement for loss of consciousness and age, body weight, and lean body mass measured by BIA and BMI (independent variables). RESULTS: Loss of consciousness was obtained with a propofol dose (Mean (SEM)) of 2.17 +/- 0.10 mg.kg-1. Stepwise analysis showed that propofol requirement (total dose) was not proportional to weight or age but related to lean body mass as determined by BIA and to body mass index (r2 = 0.447; global P- value < 0.007). BMI was the only regressor variable when the propofol dose was expressed in mg.kg-1 (r2 = 0.661; P < 0.001). CONCLUSIONS: Our results indicate that propofol requirements for induction are proportional to the lean body mass rather than total body weight.
OBJECTIVES: Vasoconstrictors are often used in gynaecology for vaginal surgery. Ornipressin was prohibited in France in 1990 and we studied the haemodynamic effect of a structural analogue marketed in France, lysine-vasopressin infused locally at the operative field. METHODS: Four haemodynamic parameters were evaluated in 7 patients undergoing surgery via the vaginal route under epidural anaesthesia (lidocaine 2%). Arterial pressure and heart rate were measured noninvasively and thoracic bioimpedance was used for measuring cardiac index and systemic vascular resistance. Baseline levels were obtained after induction of anaesthesia and positioning the patient. Five units of lysine-vasopressin diluted in 20 ml of 9/1000 saline solution were infused locally into the cervix. Haemodynamic measures were made for 15 minutes. RESULTS: Five minutes after infusion, there was a significant increase in systolic (+21 +/- 7%) and diastolic (+29 +/- 9%) arterial pressure (p < 0.05) (Mann and Whitney U test). There was a tendency for bradycardia which did not reach significance. The systemic arterial resistances were increased from 3080 +/- 178 to 4965 +/- 227 ohm/m3 with concomitant drom in systolic index from 2.6 +/- 0.3 to 1.6 +/- 0.11 min/m2. The observed haemodynamic effects were similar to those obtained with onipressin and corresponded to a sudden increase in post-charge. Cardiac tolerance was poor with a drop in systolic index to a level corresponding to a fall in cardiac inotropism and coronary blood flow. CONCLUSION: With this product, the patients are exposed to the same diseases and accidents described for ornipressin and thus should be used with extreme care, in adapted situations by competent experienced surgeons for patients without cardiovascular or cerebral diseases.
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Recent clinical studies have suggested that alkalinization of local anaesthetic agents may shorten the onset time and lengthen their duration of action. In clinical practice, sodium bicarbonate 1.4 and 4.2% are often added to local anaesthetic agents to obtain these effects. We evaluated pH changes of 4 local anaesthetic solutions commonly used for obstetrical epidural anaesthesia, in order to develop titration curves with sodium bicarbonate 1.4 and 4.2%. Local anaesthetic agents tested included lidocaine 2% and bupivacaine 0.25% with and without epinephrine. Each one was divided in 10 mL aliquots, and supplemented with 25 micrograms of sufentanil (1 mL). The pH measurement were made with a pH-meter P 500 with a combined electrode (TBC 12/HS) in the standard solution and after incremental addition of 0.5 mL of 1.4 or 4.2% sodium bicarbonate. The percentage of the free form of local anaesthetic was calculated for each step, using the Henderson-Hasselbalch equation. Results showed that alkalinization is not beneficial with epinephrine free solutions. Increasing volumes of sodium bicarbonate, buffered the acidic effect of sodium bisulfite present in solutions containing epinephrine, and increased the percentage of the free form of local anaesthetic to the level of epinephrine free solutions. From this pH point upwards, the gain is poor and precipitates are generated. This study suggests that 1 mL of 4.2% sodium bicarbonate for 10 mL of local anaesthetic solution is the best theorical choice for alkalinization of a local anaesthetic associated with epinephrine.
Hysteroscopic surgery with the use of a resectoscope are currently going through major developments. They are often aimed at healthy women who consider having relatively minor surgery. Many complications can affect endometrial resection. Some metabolic complications due to the irrigating liquid have been identified recently in gynaecological surgery, and can be defined as the whole group of clinical symptoms linked to the passage of the irrigation liquid into systemic circulation. Neurological and cardiovascular disorders are due to an acute dilutional hyponatremia and to the very toxicity of glycol and/or of its metabolites. The way the irrigating liquid is resorbed has an effect on the order in which these accidents happen. The duration of the resection, its depth, as well as the intrauterine pressure are the three factors which make it easier for a clinical syndrome to appear. Whatever the mechanism responsible, the clinical and biological consequences are the same and can be more or less serious, depending on how much liquid has been resorbed: they are non-existent up to one liter, and appear between 1.5 and 2 liters. Recent studies have shown that natremia and glycinemia are closely and inversely related. By taking a number of precautions, accidents--which are relatively rare but can be very serious--could be prevented.
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