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Biomedical subjects

C Lysakowski

Publications and source records attributed to C Lysakowski.

9 recordsLinked to original sources
PubMed2006

The effect of cigarette smoking on the hypnotic efficacy of propofol.

The bispectral index (BIS) was used to examine the hypnotic efficacy of propofol in 25 smokers (20 cigarettes/day for 2 years) and 24 matched non-smokers (same gender, age, height, weight). BIS was recorded at baseline, at four incremental effect-site concentrations of propofol and at loss of consciousness. Compared with non-smokers, smokers were found to have higher BIS values at baseline (mean (SD)) (97 (1) vs 98 (1)), at 0.7 microg x ml(-1) (95 (3) vs 97 (1)) and at 1.1 microg x ml(-1) (89 (6) vs 94 (4)), p = 0.0099, and they lost consciousness at higher propofol concentrations (2.0 (0.4) vs 2.4 (0.8) microg x ml(-1)), p = 0.03, and at lower BIS values (66 (10) vs 60 (10)), p = 0.04. The hypnotic efficacy of propofol is reduced when used at low effect-site concentrations in smokers. This phenomenon may have some impact on the management of smokers undergoing sedation using target controlled infusion systems.

Adult↗
PubMed2003

[High altitude cerebral oedema].

Acute mountain sickness and high altitude cerebral edema are specific pathologies of high altitude exposure. The usual symptoms of acute mountain sickness are headache, nausea, vomiting, insomnia, lassitude, dizziness and ataxia. High altitude cerebral oedema is a severe state of acute mountain sickness with, in addition, alteration of mental status and consciousness. The pathophysiology of these 2 diseases are essentially due to an increase of intracranial pressure directly dependent of an increase of cerebral volume. Molecular and cellular mechanisms underlying acute mountain sickness and high altitude cerebral oedema are still poorly understood. The regulation of cerebral blood flow by nitric oxide seems to play a major role.

Altitude Sickness↗
PubMed2003

Propofol 1% versus propofol 2% in children undergoing minor ENT surgery.

BACKGROUND: The induction characteristics of propofol 1% and 2% were compared in children undergoing ENT surgery, in a prospective, randomized, double-blind study. METHODS: One hundred and eight children received propofol 1% (n=55) or 2% (n=53) for induction and maintenance of anaesthesia. For induction, propofol 4 mg kg(-1) was injected at a constant rate (1200 ml h(-1)), supplemented with alfentanil. Intubating conditions without the use of a neuromuscular blocking agent were scored. RESULTS: Pain on injection occurred in 9% and 21% of patients after propofol 1% and 2%, respectively (P=0.09). Loss of consciousness was more rapid with propofol 2% compared with propofol 1% (47 s vs 54 s; P=0.02). Spontaneous movements during induction occurred in 22% and 34% (P=0.18), and intubating conditions were satisfactory in 87% and 96% (P=0.19) of children receiving propofol 1% or 2%, respectively. There were no differences between the two groups in respect of haemodynamic changes or adverse events. CONCLUSIONS: For the end-points tested, propofol 1% and propofol 2% are similar for induction of anaesthesia in children undergoing minor ENT surgery.

Adenoidectomy↗
PubMed2001

Effects of fentanyl, alfentanil, remifentanil and sufentanil on loss of consciousness and bispectral index during propofol induction of anaesthesia.

The bispectral index (BIS) and a sedation score were used to determine and compare the effect of propofol in the presence of fentanyl, alfentanil, remifentanil and sufentanil. Seventy-five non-premedicated patients were assigned randomly into five groups (15 in each) to receive fentanyl, alfentanil, remifentanil, sufentanil or placebo. Opioids were administered using a target-con-trolled infusion device, to obtain the following predicted effect-site concentrations: fentanyl, 1.5 ng ml(-1); alfentanil, 100 ng ml(-1); remifentanil, 6 ng ml(-1); and sufentanil, 0.2 ng ml(-1). After this, a target-controlled infusion of propofol (Diprifusor) was started to increase concentration gradually, to achieve predicted effect-site concentrations of 1, 2, and 4 microg ml(-1). At baseline and at each successive target effect-site concentration of propofol, the BIS, sedation score and haemodynamic variables were recorded. At the moment of loss of consciousness (LOC), the BIS and the effect-site concentration of propofol were noted. The relationship between propofol effect-site concentration and BIS was preserved with or without opioids. In the presence of an opioid, LOC occurred at a lower effect-site concentration of propofol and at a higher BIS50 (i.e. the BIS value associated with 50% probability of LOC), compared with placebo. Although clinically the hypnotic effect of propofol is enhanced by analgesic concentrations of mu-agonist opioids, the BIS does not show this increased hypnotic effect.

Adult↗
PubMed2001

Transcranial Doppler versus angiography in patients with vasospasm due to a ruptured cerebral aneurysm: A systematic review.

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) is used for diagnosis of vasospasm in patients with subarachnoid hemorrhage due to a ruptured aneurysm. Our aim was to evaluate both the accuracy of TCD compared with angiography and its usefulness as a screening method in this setting. METHODS: A search (MEDLINE, EMBASE, Cochrane Library, bibliographies, hand searching, any language, through January 31, 2001) was performed for studies comparing TCD with angiography. Data were critically appraised using a modified published 10-point score and were combined using a random-effects model. RESULTS: Twenty-six reports compared TCD with angiography. Median validity score was 4.5 (range 1 to 8). Meta-analyses could be performed with data from 7 trials. For the middle cerebral artery (5 trials, 317 tests), sensitivity was 67% (95% CI 48% to 87%), specificity was 99% (98% to 100%), positive predictive value (PPV) was 97% (95% to 98%), and negative predictive value (NPV) was 78% (65% to 91%). For the anterior cerebral artery (3 trials, 171 tests), sensitivity was 42% (11% to 72%), specificity was 76% (53% to 100%), PPV was 56% (27% to 84%), and NPV was 69% (43% to 95%). Three of these 7 studies reported on the same patients, each on another artery, and for 4, data recycling could not be disproved. Other arteries were tested in only 1 trial each. CONCLUSIONS: For the middle cerebral artery, TCD is not likely to indicate a spasm when angiography does not show one (high specificity), and TCD may be used to identify patients with a spasm (high PPV). For all other situations and arteries, there is either lack of evidence of accuracy or of any usefulness of TCD. Most of these data are of low methodological quality, bias cannot not be ruled out, and data reporting is often uncritical.

Blood Flow Velocity↗
PubMed2000

Mivacurium or vecuronium for paediatric ENT surgery. Clinical experience and cost analysis.

BACKGROUND: The present study compared the quality of neuromuscular block and costs after equipotent doses of mivacurium and vecuronium in the context of paediatric ENT surgery. METHODS: A total of 30 children undergoing elective tonsillectomy were included and randomised in two groups (n = 15 for each) according to the neuromuscular blocking agent (NMBA) used. Anaesthesia was induced with alfentanil (15 micrograms/kg), propofol (3 mg/kg) and either 0.2 mg/kg mivacurium or 0.14 mg/kg vecuronium. For maintenance of anaesthesia propofol (8-12 mg/kg/h) was given. Neuromuscular block was assessed by electromyography using train-of four stimulation and the following parameters were quantified: Twitch height (T1) 2 min after the initial bolus of the myorelaxant; duration until recovery to 10% T1, number and duration of bolus injections of the myorelaxant needed to maintain neuromuscular block to a T1 < 10%. In addition, the intubating conditions, number of patients needing pharmacological reversal at the end of surgery, adverse reactions and the costs for neuromuscular block and pharmacological antagonization were assessed. RESULTS: Intubation conditions were comparable between both study groups: mivacurium--excellent: 7, good: 5, not acceptable: 1; vecuronium--excellent: 11, good: 4 (n.s.). T1 at 2 min was 16 (15)% for mivacurium and 6 (9)% for vecuronium (P < 0.05). Time to 10% T1 recovery was 6.1 (1.7) min for mivacurium and 21.8 (3.7) min for vecuronium (P < 0.01). In the mivacurium group 7 repetitive doses (range: 4-18) were needed to maintain T1 < 10% during surgery, whereas children treated with vecuronium needed only 1 maintenance dose (range: 0-2) (P < 0.01). Two children in the mivacurium group and 11 in the vecuronium group required pharmacological reversal of the NMB at the end of surgery (P < 0.01). The overall costs of NMB were significantly higher in the mivacurium group as compared to vecuronium 12.88 (4.5) Euro vs 9.96 (2.4) Euro; P < 0.05. CONCLUSIONS: In conclusion, mivacurium-induced NMB is of very short duration in paediatric patients, and therefore repetitive doses are required to maintain a deep neuromuscular block. Nevertheless, residual paralysis is less frequent after mivacurium. The neuromuscular block after mivacurium was more expensive and residual paralysis less frequent compared to vecuronium.

Child↗