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Biomedical subjects

G Bonada

Publications and source records attributed to G Bonada.

5 recordsLinked to original sources
PubMed1996

Potentiation of atracurium by pancuronium during propofol-fentanyl-N2O anesthesia.

At the end of abdominal surgery deep neuromuscular blockade is required for peritoneal closure. Ideally injecting an intermediate acting drug like atracurium after a long acting drug such as pancuronium should deepen the neuromuscular block without the fear of an inadequate reversal at the completion of surgery. Thirty patients ASA I or II status, without known allergy to myorelaxant and without neuromuscular, hepatic or renal failure were included in this study. Anesthesia was induced and maintained with propofol, fentanyl, and N20. Normal core temperature was maintained by active warming of the upper part of the body. Blood electrolytes and the acid-base status were within the normal range. The accelerographic responses to Train-Of-Four supramaximal stimulation (TOF) of the ulnar nerve was monitored at the thumb. After obtaining a stable response with the accelerograph, the patients randomly received pancuronium (0.10 mg.kg-1, group I, n = 10 and group II, n = 10) or atracurium (0.50 mg.kg-1, group III, n = 10). An additional dose of atracurium (0.16 mg.kg-1, group I and III) or pancuronium (0.03 mg.kg-1, group II) was injected when the first response of TOF stimulation (T1) reached 25% of its initial value. Then the time to obtain a 25% twitch height of T1 (T25), the recovery index (RI 25-75), the delay to obtain 4 responses to TOF and an adequate recovery [TOF ratio of 0.70 (TOF70)] were monitored. Injection of 60% ED95 of atracurium after pancuronium resulted in a similar recovery of neuromuscular function as after 45% ED95 of pancuronium as shown by the same recovery of T25 (66.5 +/- 4.2 min versus 71.4 +/- 7.8 min, group I versus group II, p > 0.05) and TOF70 (131.6 +/- 15.7 min versus 144.0 +/- 17.5, group I versus II, p > 0.05). Nevertheless the RI 25-75 of group I was of intermediate duration between those of group II and III. Electrolytes and acid-base status were similar between groups at the beginning of surgery. Thus this study shows a synergistic effect of the combination of atracurium after pancuronium occurring in non hypothermic patients anesthetized without halogenated agents. Because the duration of action of the drug administered first governs the duration of action of the subsequent neuromuscular myorelaxant, the neuromuscular function should be closely monitored at the end of surgery if neuromuscular drugs are used in combination.

Anesthetics, Inhalation↗
PubMed1994

[Diprivan and electroconvulsive therapy].

Anaesthesia for Electroconvulsive Therapy (ECT) is characterized by short repeat anaesthetic procedures, performed outside an operating theatre. The efficacy of ECT relies upon the occurrence of tonoclonic convulsions. Propofol seems to be the intravenous induction agent of choice for ECT. Its pharmacokinetic properties ensure a rapid and deep anaesthesia, of short duration, with a minimum of side effects, and a rapid recovery of good quality, suitable for short repetitive procedures. As low doses of propofol are used, a rapid injection is required to obtain the hypnotic effect. These low doses also have the advantage of not affecting the convulsion threshold and therefore the efficacy of ECT. Clear upper airways and prevention of tongue biting are ensured by inserting a Guedel airway after loss of consciousness and before the electric shock. Intravenous administration of 10-20 micrograms.kg-1 atropine prevents from bradycardia, related to initial vagal stimulation induced by the electric shock. Its action is potentiated by the anticholinergic effect of tricyclic antidepressants. Its use is also justified when suxamethonium is given to prevent patient's movements and possible ECT-related trauma. Only suxamethonium is suitable for these procedures because of its pharmacokinetic properties (rapid onset and short duration of action). The suggested doses for this indication range from 0.5 to 1 mg.kg-1. When contraindicated, suxamethonium may be replaced by a benzodiazepine, in order to achieve an acceptable degree of muscle relaxation. There may then be an effect on the convulsion threshold.

Anesthesia, Intravenous↗
PubMed1993

[Infusion of propofol or closed-circuit isoflurane. A study of cost].

The choice of an anaesthetic agent is influenced by its cost. The use of a circle absorber system decreases the cost of the maintenance of anaesthesia with halogenated agents. Fast recovery and low incidence of postoperative nausea and vomiting are the main advantages of propofol. The cost of propofol can limit its use for the maintenance of anaesthesia except for short procedures. This prospective study compared in 50 ASA 1 and 2 patients the cost of anaesthesia with either propofol (group P, n = 25) or the association thiopentone-isoflurane administered with a rebreathing circuit (group I, n = 25). Patients were premedicated the evening before surgery with 2.5 mg lorazepam. Anaesthesia was induced with either propofol (2-3 mg.kg-1) or thiopentone (4-6 mg.kg-1) and maintained with either propofol (6-10 mg.kg-1.h-1) in group P or isoflurane continuously injected as liquid in the expiratory limb of the circuit in group I. The side effects of anaesthesia and the delay of recovery and discharge from the recovery room were assessed. Peroperative cost of anaesthesia included nitrous oxide, isoflurane and i.v. agents, fluids volumes and disposable devices. The total cost of anaesthesia included also the recovery room stay. The mean duration of anaesthesia was not significantly different between the two groups (109.4 +/- 7.1 min vs 107.3 +/- 7.3 min group P vs group I). The delay lf recovery (eyes opening) was shorter in the propofol group (14.4 +/- 1.3 min vs 19.4 +/- 1.4 min) as well as the delay of discharge from the recovery room (70 +/- 4 min, vs 82.4 +/- 4.6 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

A comparison between lidocaine alone and lidocaine with meperidine for continuous spinal anesthesia.

BACKGROUND AND OBJECTIVES: Experimental investigations have demonstrated a synergistic interaction between opioids and local anesthetics. This study aims to assess the effective benefit-risk ratio of continuous spinal anesthesia (CSA) induced with either 1.6% lidocaine alone or in combination with 1% meperidine. METHODS: Thirty-four elderly patients (80.7 +/- 7.3 years) operated on for fracture of the neck of the femur were randomly allocated to two groups. In the first group (n = 15), CSA was induced with lidocaine 1.6% plain, whereas in the second group (n = 19) 1% meperidine was added. Reinjections were performed in both groups using lidocaine 1.6% alone. RESULTS: In the lidocaine group, 43 +/- 13 mg was used for induction whereas in the other group the addition of 18 +/- 5 mg of meperidine significantly reduced the dose of lidocaine required to 28 +/- 8 mg (p < 0.001). Delay between two reinjections was increased to 51 +/- 7 minutes in the lidocaine plus meperidine group, compared to 35 +/- 6 minutes in the lidocaine group (p < 0.001). Ephedrine was required for 9 out of the 19 patients in the lidocaine plus meperidine group, whereas it was required for only two patients in the other group (p = 0.05). Mean plasma concentrations of meperidine 1 hour and 3 hours after induction was 45.5 +/- 12 ng/ml and 59 +/- 22 ng/ml, respectively, and drowsiness was observed in 95% of the patients in the second group. Delay before requirement for pain medication was 2.2 +/- 2 hours in the lidocaine group and 14.1 +/- 8 hours in the lidocaine plus meperidine group (p < 0.001). CONCLUSIONS: The association of 1% meperidine with 1.6% lidocaine during the induction of CSA decreases the initial induction dose, prolongs analgesia, produces initial drowsiness, and provides long-lasting pain relief. However, such benefits are offset by some impairment of hemodynamic stability that is likely to make this combination of drugs unacceptable as an enhanced analgesic technique.

Aged↗