Articles: anesthetics.
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Anesthesia and analgesia · Nov 1988
Comparative StudyComparative motor-blocking effects of bupivacaine and ropivacaine, a new amino amide local anesthetic, in the rat and dog.
Ropivacaine (S-(-)-1-propyl-2',6'-pipecoloxylidide) is a new local anesthetic that is structurally related to mepivacaine and bupivacaine. The comparative effects of ropivacaine and bupivacaine on motor function were assessed in the laboratory rat and dog. (It was not possible to accurately evaluate sensory blockade in these models.) Several concentrations of both agents were injected in the region of the sciatic nerve of the rat and into the lumbar epidural or subarachoid space in the dog. Epidural blockade was also performed utilizing solutions of ropivacaine and bupivacaine which contained epinephrine (1:200,000). ⋯ In the epidural and spinal studies in the dog, ropivacaine was less potent and had a shorter duration of motor blockade than did bupivacaine at equal drug concentrations. A 1.0% solution of ropivacaine produced epidural motor blockade similar in onset and duration to that achieved with a 0.75% solution of bupivacaine. Epinephrine did not significantly prolong the duration of motor blockade of either agent after epidural administration.
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In a study of 144 children aged 1-12 years, attempts were made to assess the ED50 and ED90 of the intravenous induction agent, propofol. The doses required for loss of eyelash reflex and tolerance of facemask, in 50% of unpremedicated children, were 1.6 mg/kg and 2.5 mg/kg respectively. ⋯ This probably corresponds to an effective induction dose. Pain and movement on induction were common; the incidence was 27% and 21.5% respectively.
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Anesthesia and analgesia · Nov 1988
Comparative StudyComparative pharmacokinetics of bupivacaine and ropivacaine, a new amide local anesthetic.
The pharmacokinetics of ropivacaine, a new amide local anesthetic, and bupivacaine were determined in dogs after IV and epidural administration. After 15-minute IV infusions of 3.0 mg/kg ropivacaine (n = 6) and 3.4 mg/kg bupivacaine (n = 4), the maximum arterial concentrations (Cmax) of ropivacaine averaged 2.41 +/- 0.52 micrograms/ml compared with 3.35 +/- 0.16 micrograms/ml of bupivacaine. The elimination half life (t 1/2 beta) of ropivacaine (25.9 +/- 1.7 min) was significantly shorter than for bupivacaine (39.1 +/- 13.3 min) after IV infusion. ⋯ No differences existed between t 1/2 beta values for ropivacaine and bupivacaine after epidural administration. Total body clearance of both agents tended to be lower after epidural administration, particularly when epinephrine-containing solutions were employed. Little difference existed between the two drugs when equivalent solutions were administered.(ABSTRACT TRUNCATED AT 250 WORDS)
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Acta Anaesthesiol Scand · Nov 1988
Cardiac arrest during anaesthesia. A computer-aided study in 250,543 anaesthetics.
With the aid of a computer-based anaesthetic record-keeping system, all cardiac arrests during anaesthesia at the Karolinska Hospital between July 1967 and December 1984 were retrieved. There were a total of 170 cardiac arrests and 250,543 anaesthetics in the data file, which gives an incidence of 6.8 cardiac arrests per 10,000 anaesthetics. Sixty patients died, constituting a mortality of 2.4 per 10,000 anaesthetics: 42 were considered as inevitable deaths (rupture of aortic or cerebral aneurysm, multitrauma, etc.); 13 cases of cardiac arrest were considered as non-anaesthetic, i.e. complications due to surgery and other procedures. ⋯ The most common cause of cardiac arrest due to anaesthesia was hypoxia because of ventilatory problems (27 patients), postsuccinylcholine asystole (23 patients) and post-induction hypotension (14 patients). The highest mortality was seen when spinal or epidural anaesthetics were given to patients with impaired physical status including hypovolaemia. The incidence of cardiac arrest has declined considerably during the period studied, and this coincides with an increasing number of qualified anaesthetists employed in the department during the same period.