Biomedical subjects
L Versichelen
Publications and source records attributed to L Versichelen.
Mass-spectrometry analysis of modern low flow anesthesia systems.
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Propofol combined with nitrous oxide-oxygen for induction and maintenance of anaesthesia.
After a bolus of 2 mg/kg, propofol was given by continuous infusion (150 micrograms/kg/minute for 30 minutes and then 100 micrograms/kg/minute) supplemented with nitrous oxide for anaesthesia during ear surgery in 12 patients. Cardiovascular changes were not significant except for a decrease in heart rate after 60 minutes. Acid-base balance was unaffected by the amount of fatty emulsion. Cortisol levels showed a nonsignificant decrease during the prolonged administration of propofol but had recovered completely by one hour following anaesthesia. Mean blood concentrations of propofol were 10.5 micrograms/ml (SEM 1.2) at the onset of unconsciousness, between 3.4 and 4.5 micrograms/ml during continuous infusion and 2.9 micrograms/ml (SEM 0.3) on awakening. Patients opened their eyes 6 minutes (SEM 1) after discontinuation of the infusion, and were responsive at 7.5 minutes (SEM 0.5), which suggests that propofol infusion can be used safely for surgery of 2 hours' duration.
Priming with vecuronium and atracurium--a comparison.
Vecuronium (V) and atracurium (A) were compared in a randomised study in premedicated patients undergoing laparoscopy for gynecological pathology. Both groups contained ten patients. Anesthesia was induced with fentanyl (0.1 mg) and thiopentone (1 mg/kg initially and subsequently 4 mg/kg). A priming dose of vecuronium (20 micrograms/kg) or atracurium (100 micrograms/kg) was given one minute before the intubating dose (60 micrograms/kg for vecuronium and 300 micrograms/kg for atracurium). Ninety seconds thereafter intubation was performed. Maintenance of anesthesia consisted of isoflurane at an inspiratory concentration of 1% in a mixture of O2/N2O (50%/50%) with small supplements of fentanyl. Neuromuscular block was monitored with the Datex Relaxograph. Results show that neither drug offers major clinical advantages over the other: there is no difference in speed of onset (V:T190sec 14.6 +/- 4.3%; A:T190sec 23.5 +/- 6.5%; Mean +/- SEM) and duration of neuromuscular block (V:T150sec 34.2 +/- 3.5 min; A:T150sec 41.3 +/- 2.8 min; Mean +/- SEM) and intubation conditions are almost identical.
Effect of speed of injection on induction of anaesthesia using propofol.
Sixty unpremedicated patients (30 male) were randomly allocated to three groups. They received an induction dose of propofol 2 mg kg-1 over 5, 20 or 60 s to a forearm vein. Anaesthesia was maintained with conventional inhalation anaesthetic agents. Anaesthesia was induced satisfactorily in all 20 of the patients in the 5-s group, in 19 of the patients in the 20-s group and in 18 of the patients in the 60-s group. The rate of injection had a significant influence on induction time. Mean induction time increased from 21.5 to 34.7 and 50.5 s, when injection time was increased from 5 to 20 to 60 s, respectively. Similar induction times were found in male and female patients. There was no significant difference between the groups, in depth of anaesthesia obtained--as assessed by the eyelash reflex. Mean arterial pressure decreased to the same extent in all three groups. Two minutes after induction, mean systolic arterial pressure was reduced by 15.1, 13.5 and 19.3 mm Hg in the 5-, 20- and 60-s groups, respectively, and mean diastolic arterial pressure by 10.3, 13.2 and 13.7 mm Hg. Heart rate changes were insignificant. Apnoea of more than 10 s duration was seen frequently in all three groups, but the results suggest that the incidence was not influenced by the rate of injection. Three patients experienced mild pain at the time of injection. No major adverse reactions occurred during or after anaesthesia.
Comparison of propofol and thiopentone for induction of anaesthesia in premedicated patients.
Thirty premedicated ASA I or II patients scheduled for minor gynaecological surgery, were randomly allocated to receive either 1.5 mg/kg or 2 mg/kg propofol of the new emulsion formulation, or 4 mg/kg thiopentone, given over 20 seconds. Anaesthesia was successfully induced in all 30 patients. The mean (SEM) induction times were for propofol 1.5 mg/kg 33.3(3.2) seconds, for 2 mg/kg 30.5(2.7) seconds and for thiopentone 34.6(2.7) seconds. The incidence of apnoea greater than 10 seconds, was respectively 60, 80 and 80%, and the mean duration of apnoea 30.8(5.3), 37.1(5.0) and 23.7(5.0) seconds. The mean systolic blood pressure decreased after propofol 1.5 mg/kg by 16.0 mmHg, after 2 mg/kg by 18.6 mmHg, and increased after thiopentone by 1 mmHg, 2 minutes after injection. Heart rate increased significantly 2 minutes after thiopentone by an average of 15.1 beats/minute, but not after propofol. Pain was not reported during or after the injection. No major adverse reactions occurred at induction or during maintenance of anaesthesia with an inhalation agent. One patient who received 2 mg/kg propofol and isoflurane vomited for 24 hours. The recovery of anaesthesia after propofol induction, was quicker than after thiopentone.
Cumulative experience with propofol ('Diprivan') as an agent for the induction and maintenance of anaesthesia.
In 60 unpremedicated patients, anaesthesia induction time decreased when the time taken to inject a bolus of 2 mg/kg propofol was decreased from 60 s to 5 s. Apnoea at induction was noted in all groups but the degree of cardiorespiratory depression was not influenced by the rate of injection. In premedicated patients both 1.5 mg/kg and 2.0 mg/kg were effective doses for induction of anaesthesia. In comparison with thiopentone 4 mg/kg, propofol produced a greater degree of arterial hypotension and a smaller increase in heart rate. Preliminary results with an infusion of propofol for maintenance of anaesthesia suggest that rapid recovery can be achieved after operations of long duration.
Anesthesia for foreign bodies in the tracheo-bronchial tree in children.
The authors present the anesthetic and ventilation techniques, used in 106 children, who were suspected of foreign body aspiration in the respiratory tract. In 62 children a foreign body was found. The youngest child was 8 months old and the oldest 13 years, with an age distribution peak in the 1 to 2 years age group. A predominance for the male sex (60%) was present. Foreign bodies of organic nature were found most frequently (80%), 39 of them consisting of peanuts. The bronchi were involved more often than the trachea and the foreign body was located more frequently at the right bronchus (38 pt). The children were ventilated initially with an intermittent oxygen jet injection technique, using a home made apparatus, but since 1978 with HFPPV, using the AGA Bronchovent. Induction of anesthesia was done with halothane and maintenance with etomidate infusion (10-20 micrograms/kg/min.) or thiopental increments (2 to 3 mg/kg). The technique so far used, proved to be satisfactory, specially since HFPPV is used. Few complications occurred. One child died during the bronchoscopic procedure and in an other child a tracheostomy had to be performed for extraction of the foreign body.
Physiopathologic changes during anesthesia administration for gynecologic laparoscopy.
The physiopathologic effects of CO2 pneumoperitoneum on the respiratory and cardiovascular systems were studied in seven patients during gynecologic laparoscopy and volume-controlled ventilation. The CO2 pneumoperitoneum and Trendelenburg position induced a statistically significant decrease in CTL and a significant increase in CVP, PaCO2 and PACO2.
Cardiovascular, metabolic and hormonal changes during isoflurane N2O anaesthesia.
Isoflurane was used in 10 ASA I or II female patients, undergoing hysterectomy. It was given at a constant inspired concentration of 1.3% in a 50% N2O/50% O2 mixture, after induction of anaesthesia using etomidate (0.3 mg kg-1) and intubation following pancuronium (0.1 mg kg-1). No analgesic supplement was given. The patients were hyperventilated minimally (PaCO2 4.7-5.3 kPa). At standardized times (before induction, after induction, 5', 25', 50' and 75' min after surgical incision, awake and awake +60'), cardiovascular (blood pressure, cardiac output, stroke volume, heart rate), respiratory (blood gases), metabolic (oxygen consumption, blood glucose) and hormonal (noradrenaline, adrenaline, cortisol, prolactin) changes were measured. Blood pressure changes were very moderate (mean values were lower than before induction), but heart rate was increased significantly. Decreases in stroke volume and changes in cardiac output were not significant. Oxygen consumption was decreased below basal values during surgery. Blood glucose levels increased significantly in the course of surgery and remained raised postoperatively. Adrenaline and noradrenaline levels increased significantly. At each examination time, cortisol levels were decreased significantly. Prolactin levels had decreased significantly 75 mins after incision and remained low 60 mins after awakening.
Mass spectrometer evaluation of closed and low flow anesthesia systems.
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Alfentanil/etomidate anaesthesia for endolaryngeal microsurgery.
Anaesthesia for laryngeal microsurgery by laser was conducted using etomidate and alfentanil. Patients' lungs were ventilated with air to avoid the danger of fire during the use of the laser. Thirty one patients received fentanyl/droperidol or pethidine for premedication. Anaesthesia was induced with etomidate 300 micrograms/kg and maintained with etomidate 30 micrograms/kg/minute. Alfentanil was given as an initial bolus of 40 micrograms/kg with subsequent increments of 15 micrograms/kg. Systolic arterial blood pressure and heart rate decreased significantly at some time intervals. Blood biochemistry and blood gases were within normal ranges, except for elevated PaO2 values during ventilation on pure oxygen. This technique adequately provided the requirements for prompt, smooth awakening, with a low incidence of nausea and vomiting.
Comparative study of etomidate-alfentanil anesthesia with N2O/O2 or with air/O2.
Systolic, diastolic blood pressures, heart rate, glycaemia, blood gases and clinical status were studied preinduction, 10' after anesthesia induction and intubation, 3', 30', 60' and 90' after surgical incision, when awake on the operating table and 60' after awakening in 20 hysterectomy patients. Etomidate (0.3 mg/kg + continuous infusion), alfentanil (75 micrograms/kg + increments of 15 micrograms/kg) anesthesia was used with a N2O/O2 mixture (10 pt) or with air/O2 (10 pt), both at a FIO2 = 0.33. This technique gave a smooth induction and recovery. Cardiovascular changes were moderate. The additional dose of alfentanil was 5.25 +/- 0.65 mg in the N2O/O2 group and 6.45 +/- 0.85 mg in the air/O2 group. The incidence of vomiting was 15%. Statistical analysis of both groups indicated no major difference between the two types of anesthesia, for the cardiovascular, acid base data and glycaemia. This technique is a simple and effective way of anesthetising patients, but from a clinical point of view the etomidate/alfentanil anesthesia combined with N2O/O2 gives better results than when combined with air/O2.
Etodolac in postsurgical pain: a double-blind dose-ranging efficacy study with aspirin and placebo.
A study was conducted to compare the analgesic activity of single oral doses of etodolac (25, 50, 100, 200, and 400 mg) with 650 mg aspirin and placebo. A total of 146 patients with moderate or severe pain from orthopedic or urologic interventions received one of the test medications 13-25 h after the beginning of surgery and according to a randomized allocation balanced as to initial pain intensity. Data for pain intensity and pain relief were collected at 1/2 h and then hourly for 8 h. Vital signs and adverse reactions were also recorded. One hundred and forty-two patients completed the study: four were excluded because of protocol deviations. The average response to 100, 200, and 400 mg of etodolac was superior to that of placebo. On the basis of SPID, TOTPAR, and duration of analgesia, 400 mg etodolac was also significantly more effective than 650 mg aspirin. Mild side effects probably or possibly related to etodolac were reported by three patients. This study provides evidence that etodolac in doses of 100 mg and higher is an effective and well-tolerated analgesic.
[Hundred cases of general anesthesia for laryngoscopy and/or bronchoscopy, in children under five years age (author's transl)].
The authors describe an anesthetic technique used for endoscopies (laryngo-tracheo-bronchoscopies) in 100 children under five years age. Three different apparatus for jet ventilation are used: manual injection, automatic injection and high frequency positive pressure ventilation. The first apparatus is home made. It allows control of insufflation of O2 by manual compression of a gun type injector. With the second one (Wolf injectomat), injection of O2 or O2/N2O is automatic. The aga bronchovent is used for high frequency positive ventilation with O2.
Use of ICI 35868 as an anesthetic induction agent.
ICI 35868 was used to induce anesthesia in 39 ASA I patients (9 male and 30 female, aged 17-64 years), scheduled to undergo minor surgical procedures. The first 6 patients were given 1.0 mg/kg, the next 22 1.5 mg/kg and the final 11 2.0 mg/kg ICI 35868 I.V. over 30 seconds, without premedication. Anesthesia was successfully induced in 100% of patients at 2.0 mg/kg, 81% at 1.5 mg/kg and 50% at 1.0 mg/kg. Pain at the injection site occurred in 23% of patients. There were no signs of venous damage postoperatively. A small transient fall in blood pressure and some respiratory depression were seen immediately after induction; transient apnoea occurred in 27% of patients given 1.5 mg/kg and 55% given 2.0 mg/kg. Other side effects were minor and of low incidence. Three minutes after induction of anesthesia, when assessments were complete, 23 patients were given a further dose of a conventional induction agent, as they were beginning to awaken, and anesthesia was maintained in all patients by inhalational techniques. There were no untoward events during maintenance of or on recover from anesthesia.
Effects of enflurane (Ethrane) anesthesia on children during short surgical procedures.
Enflurane, a new inhalation anesthetic agent, was administered as primary anesthetic agent to children undergoing elective surgery of +/- 20 minutes duration in Oto-Rhino-Laryngology. Induction was done by enflurane (0.2 - 3.5%) given in a mixture of 50% N2O/O2 and maintenance was done with 2% enflurane and N2O/O2 mixture. Induction and recovery were rapid and uneventful. Regarding the cardiovascular system, we observed, during the first ten minutes of anesthesia, a significant drop of blood pressure which almost always returned to normal when the surgical stimulus was applied. Respiratory depression was negligiable in the spontaneously breathing patients. No ECG changes were observed. Postanesthetic side effects were minimal. Keeping in view the reports of other authors and our own results, we conclude that enflurane is a safe and well suited anesthetic in pediatric anesthesia of relatively short duration with spontaneous respiration.
Double blind study of nefopam, tilidine or placebo, on postoperative pain relief.
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