Biomedical subjects
Publications and source records attributed to R Souron.
A case of postoperative failure after total hip replacement is described. A gastric tube was passed and the stomach was seen to be within the right hemithorax on the chest X-ray. Aspiration of gastric gas and juice relieved the respiratory symptoms.
The present study investigated the effects of propofol (P) as sole anaesthetic agent of left ventricular (LV) function using gated radionuclide ventriculography (RNV) in unpremedicated patients with chronic coronary arterial disease (CAD). After informed consent, seven ASA 111 patients (51-74 yr) undergoing major urologic surgery took part in this study. All patients suffered from documented angina pectoris secondary to CAD. None gave a history of congestive heart failure or valvular heart disease. No patients were premedicated, but all received their chronic medications (nifedipine and isosorbide) up to and including the morning of surgery. The study was performed in the Nuclear Medicine Laboratory just before surgery. Heart rate (HR) was obtained from standard limb lead II of the ECG. A 7.5 F thermodilution Swan-Ganz catheter and a radial artery cannula were inserted under local anaesthesia. All patients were studied by RNV using red blood cells (RBC) labelled in vivo with 99m-technetium (Tc). A first RBC-Tc preparation containing 2-3 mCi f Tc was counted 10 cm from a gamma-camera. A first-pass study was carried out in the left anterior oblique position following the bolus i.v. injection of the source, allowing the evaluation of the isotopic dilution cardiac output (COiso) and the attenuation factor (F). Then, a second RBC-Tc preparation containing 20-25 mCi of Tc was injected intravenously. At equilibrium, 16 ECG-synchronized frames were acquired by computer for processing. Mean end-diastolic (ED) and end-systolic (ES) counts, left ventricular-end diastolic and systolic areas and ejection fraction (EF) were calculated every 1.5 min.(ABSTRACT TRUNCATED AT 250 WORDS)
Haemodynamic data (thermodilution Swan-Ganz catheter and radial artery cannula) were collected in 17 patients (52.4 +/- 8 yr) during retrosigmoid approach for removal of an acoustic tumour in the seated position. Measurements were made before stimulation of posterior fossa structures (period 1) and during tumour dissection along the brain stem (period 2). Significant increases in systolic, diastolic and mean blood pressures, in pulmonary capillary wedge pressure, in cardiac index and in stroke index were observed during period 2, whereas heart rate, right atrial pressure and systemic vascular resistances were unaffected. The greater the size of the tumour and the difficulties in dissection, the greater were these intraoperative haemodynamic changes. In addition, the pulmonary arterial blood temperature and the noradrenaline plasma concentrations (double isotope enzymatic assay) increased significantly during period 2. In conclusion, the prolonged microsurgical technique of acoustic tumour dissection through the retrosigmoid approach may modify left ventricular loading conditions and may lead to pulmonary oedema, even if intravascular volume expansion was minimal and ventricular function was near normal.
Thirty-six patients were anaesthetized for a maxillofacial surgical procedure. Ventilation was controlled by a ventilator (Kontron ABT 4100) with a semi-closed circle system. The flow of fresh gases was 1,200 ml.min-1. The vaporizer for the halogenated anaesthetic agent was placed out of the circle before the ventilator. Halothane was used for maintenance of anaesthesia and isoflurane for induced hypotension in orthognathic surgery. The inspired concentration of the halogenated agent was monitored by an analyser. A linear correlation between the delivered and the inhaled concentration of halogenated agent was established, the latter never reaching the delivered concentration. Monitoring the inspired oxygen concentration was required, so as to maintain a constant value. Carbon dioxide absorption by soda lime was also studied. The known advantages were: substantial economies in nitrous oxide and halogenated agents, prevention of contamination of the operating theatre, humidification and warning of the inspired gases. The use of such a system with the vaporizer out of the circle was safe, all the more so as the concentration of inhaled halogenated agents could be predicted.
The use of atracurium, a new intermediate duration of action non depolarizing muscle relaxant, is described in a myasthenic patient undergoing abdominal surgery. The effective dose to 95% twitch suppression is 0.15 mg.kg-1. Following the first dose, the time from maximum twitch depression to 25% recovery is 32 min, and 33 min following the second dose. The recovery index (25-75% recovery time) and the 5-90% recovery time are respectively 33 and 83 min. The train-of-four ratio is greater than 0.7 within 90 min after the reinjection. The significance of the behaviour of atracurium is discussed. In reduced dosage and with careful neuromuscular monitoring, atracurium appears to be a reasonable and safe choice of myasthenic patients to provide surgical relaxation.
Twenty patients with end-stage renal failure, undergoing kidney transplantation, were assigned randomly to receive either vecuronium or atracurium under evoked twitch tension control. The cumulative-dose technique was used to obtain 95% twitch depression (vecuronium: initial bolus 15 micrograms kg-1, increments 6 micrograms kg-1; atracurium: initial bolus 100 micrograms kg-1, increments 40 micrograms kg-1). Using ED95 values derived from the log-probit dose-response curves, vecuronium was 4.6 times more potent than atracurium. The durations of action of the initial cumulative-doses (from end of injection of the last increment to 25% recovery) were 11.1 +/- 3.3 min for vecuronium and 16.2 +/- 3.9 min for atracurium (P less than 0.05). In terms of duration of action of the maintenance doses (vecuronium one-quarter of the total incremental dose; atracurium one-third) some cumulation was observed with vecuronium (interaction time X treatment; cumulation ratio 1.46 +/- 0.31 v. 0.98 +/- 0.10 for atracurium, P less than 0.001). After 2 h of surgery, the mean recovery times (25% to 75% twitch height) did not differ (18.5 +/- 2.8 min and 16.7 +/- 4.4 min). It is concluded that vecuronium might be less safe than atracurium in patients with end-stage renal failure undergoing prolonged operations.
We compared, at constant preload maintained by polygeline (gelatin) infusion, the hemodynamic effects of continuous infusion of norepinephrine (0.5, 1, and 1.5 micrograms/kg X min) in anesthetized dogs with and without hyperdynamic endotoxic shock. In both groups, norepinephrine infusion increased systolic, diastolic and mean aortic BP, cardiac index, stroke index, index of myocardial contractility, and mean pulmonary artery pressure. No significant change in right atrial pressure, left ventricular end-diastolic pressure, heart rate, systemic vascular resistance, or pulmonary vascular resistance was observed. Oxygen consumption index and oxygen extraction ratio remained unchanged. Increases in systolic aortic BP were dose-related, whereas maximal effects on other variables were obtained at 0.5 to 1 microgram/kg X min. The rise in aortic pressure resulted from an increased cardiac index but not from an increased systemic vascular resistance. Stroke index increased as contractility improved. The slight alpha-adrenergic effect of continuous, low-dose norepinephrine infusion did not impede the beneficial effects of the marked beta-adrenergic stimulation on cardiac function. The combination of these two effects improved hemodynamic disturbances of hyperdynamic endotoxic canine shock.
Peroperative thermal losses were studied in 28 patients (mean age 64 years) operated for a total hip prosthesis under controlled hypotension. The patients were split into four groups according to the method of hypothermia prevention used: reflective blanket, heating humidifier of inhaled gases, combination of both techniques or no prevention at all. The thermal loss was quicker and more intense in the last group. The superiority of one prevention method over another could not be demonstrated, but the urgency of its implementation proved to be essential.
After randomization in 2 groups of 20, 40 adult patients with a severe urinary tract infection (post-urologic surgery, pyelonephritis, prostatitis, neurologic bladder dysfunction, Foley catheter) received as first-line therapy, ceftriaxone (CFX) 1 g/24 h im or amikacin (AMK) 500 mg/24 h im during at least 5 days. The clinical and bacteriological efficiency and the tolerance of the 2 agents are equivalent. In the 2 groups, all patients but one are clinically cured. In the CFX group, 2 patients had resistant organisms (E. cloacae, strepto D) to first-line antibiotic. 48 hours after the beginning and at the end of the treatment, the percentage of urine sterilization was respectively 65 and 88 in the CFX group and 50 in the AMK group. In both groups, 60% of the patients showed negative first-month follow-up urine specimen. Underlying urinary tract pathology contributed to persistence of the original infecting organism, reinfection or relapse; the responsible isolate remained sensitive to the first-line antibiotic.
The potential for inducing hypotension during fentanyl anaesthesia by administering either diltiazem (n = 7) or sodium nitroprusside (n = 7) was investigated during total hip arthroplasty. Haemodynamic variables were obtained in the lateral position before, during and after administration of the hypotensive agent. Diltiazem 0.15 mg X kg-1 given as an IV bolus followed by a 12.5 +/- 3 micrograms X kg-1 X min-1 continuous infusion decreased mean arterial pressure (MAP) from 77 +/- 11 mmHg to 63 +/- 16 mmHg (p less than 0.05) while other haemodynamic parameters showed only minor and insignificant changes. Hypotension continued for at least 30 min after the cessation of diltiazem. With sodium nitroprusside MAP decreased immediately from 81 +/- 11 mmHg to 59 +/- 9 mmHg (p less than 0.01) and rapidly returned to its control value after cessation of the infusion. CI and Qs/Qt rose significantly (p less than 0.05) while the systemic vascular resistance index (SVRI) (p less than 0.01) and pulmonary vascular resistance index (PVRI) (p less than 0.05) fell significantly. The haemodynamic profile was significantly different between hypotensive agents for MAP (p less than 0.02), heart rate (HR) (p less than 0.01), SVRI (p less than 0.05), and PVRI (p less than 0.05). HR was lower with diltiazem than with nitroprusside. A bradycardia less than 50 beats/min was observed in five patients in the diltiazem group. MAP, SVRI and PVRI were lower with nitroprusside than with diltiazem. Diltiazem can induce and maintain moderate hypotension without tachycardia and decreased cardiac output in humans during fentanyl anaesthesia but the modulation of the level of arterial pressure and the depression of atrioventricular conduction are unpredictable.
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A 17 year old man was anaesthetized for osteosynthesis of a fractured left femoral diaphysis. Endotracheal intubation was easy, anaesthesia and surgery were both uneventful. On recovery, some hoarseness was noticed. Two months later, an ENT examination showed signs of laryngeal paralysis. The presumed explanation was compression of the recurrent nerve by the high-positioned balloon of the tracheal tube. Recovery was complete four months later.
The risk of hepatitis B, previously reported in other countries, has never been investigated in French anaesthetic medical staff. The prevalence of hepatitis B viral markers has been calculated among the medical staff of the Department of Anaesthesiology, the hospital health care personnel, patients before surgical procedure and renal transplantation patients. The frequency in anaesthesiologists (18.75%; 12 out of 64) was significantly greater (p less than 0.05) than in health care personnel (10.5%; 91 out of 863). Prevalence increased with the length of practice in anaesthesiology. Prevalence of markers is 8.7% (27 out of 196) in patients undergoing surgery and 82% (27 out of 33) in patients operated on for renal transplantation in 1981. Frequency of carriers of the hepatitis B surface antigen is 0% in medical staff, 0.2% in health care personnel and 0.5% in patients before surgery. Among the health care staff, anaesthesiologists belong to a high risk population for hepatitis B. Prevention by administration of hepatitis B vaccine is recommended to protect the anaesthesiologist, his relatives and his patients.
Infants with Pierre Robin syndrome often present the anaesthesiologist with the challenge of upper airway obstruction and difficult tracheal intubation. An unconventional method for solving this problem was used in a 2 week old 2.2 kg term male infant who presented with severe micrognathia, a widely cleft palate and extreme glossoptosis. Hyperextension of the head in the prone position distracted the epiglottis from the glottis. Blind nasotracheal intubation was then used. The curve of the nasotracheal tube made it pass behind the epiglottis into the larynx.
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