Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1996
Randomized Controlled Trial Clinical TrialIntraoperative ketorolac has an opioid-sparing effect in women after diagnostic laparoscopy but not after laparoscopic tubal ligation.
Ketorolac tromethamine (Toradol) is a parenteral, nonsteroidal antiinflammatory drug that is being extensively used to provide postoperative analgesia. This study evaluated whether intraoperative ketorolac would act synergistically with fentanyl to decrease postoperative analgesic requirements in outpatients undergoing gynecologic procedures. The patients studied were adult ASA physical status I or II females scheduled for diagnostic laparoscopy (DL) (n = 80) or laparoscopic tubal ligation (TL) (n = 46). ⋯ This study showed that intraoperative ketorolac (60 mg i.v.) with fentanyl (2 micrograms/kg i.v.) administered at the induction of anesthesia resulted in significant opioid sparing and a diminution in pain in the DL sample but not in the TL sample. The analgesic regimen was also associated with a lower incidence of nausea and vomiting and resulted in earlier discharge, which was not seen after TL. These results demonstrate that pain after TL is far greater than that after DL, which suggests that these procedures should be considered separately when designing analgesic regimens.
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Anesthesia and analgesia · Apr 1996
Randomized Controlled Trial Clinical TrialThe onset of rocuronium, but not of vecuronium or mivacurium, is modified by tourniquet inflation.
A previous investigation showed that inflation of a tourniquet did not interrupt onset of vecuronium neuromuscular block. To test the hypothesis that this effect depended on potency, twitch tension was measured in an arm with a tourniquet inflated during onset and compared with a control arm in 30 patients under fentanyl-thiopental-nitrous oxide-isoflurane anesthesia. Patients were randomly allocated to receive either vecuronium 0.1 mg/kg (n = 10), rocuronium 0.6 mg/kg (n = 10), or mivacurium 0.2 mg/kg (n = 10). ⋯ The difference in maximum neuromuscular block between arms was 17% +/- 7%, 5% +/- 5%, and 0% +/- 2% in the rocuronium, vecuronium, and mivacurium groups (P < 0.05). To explain that onset of block continues in spite of interruption of blood flow, drug molecules must gain access to the neuromuscular junction via routes other than the circulation. The results of this investigation are consistent with the hypothesis that there is redistribution of drug from extrajunctional to junctional areas during onset of action of muscle relaxants and this process is more important for the more potent drugs (vecuronium and mivacurium) than for rocuronium.
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Anesthesia and analgesia · Apr 1996
Clinical Trial Controlled Clinical TrialMild intraoperative hypothermia reduces production of reactive oxygen intermediates by polymorphonuclear leukocytes.
Mild hypothermia directly impairs numerous immune functions in vitro. However, the in vivo effects of mild hypothermia on neutrophil phagocytosis and oxidative killing remain unknown. We tested the hypothesis that mild intraoperative hypothermia decreases neutrophil phagocytic capacity and generation of reactive oxygen intermediates (a measure of oxidative killing). ⋯ Production of oxidative intermediates was most closely related to intraoperative core temperature, decreasing nearly fourfold over a 4 degree C range. This in vitro temperature dependence was matched in vitro. Impaired neutrophil oxidative killing may contribute to the observed hypothermia-induced reduction in resistance to infection.
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Anesthesia and analgesia · Apr 1996
Variability of motor-evoked potentials recorded during nitrous oxide anesthesia from the tibialis anterior muscle after transcranial electrical stimulation.
When recorded as a compound muscle action potential (CMAP), the motor-evoked potential (MEP) is affected by volatile anesthetics and nitrous oxide. However, MEPs recorded using epidural electrodes in the presence of nitrous oxide are highly reproducible from trial to trial. We wished to establish the reproducibility over time of the CMAP produced by supramaximal transcranial electrical stimulation of the human motor cortex. ⋯ In addition, occasional individual stimuli, although rarely successive ones, failed to evoke a CMAP. CMAPs have a much higher trial-to-trial variability than corticospinal volleys recorded from the epidural space. Using the present methodology it would be difficult to rely on CMAP recordings as an indicator of corticospinal function in the clinical monitoring situation.
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Anesthesia and analgesia · Apr 1996
Factors affecting production of compound A from the interaction of sevoflurane with Baralyme and soda lime.
Various alkali (e.g., soda lime) convert sevoflurane to CF2=C(CF3)OCH2F, a vinyl ether called "Compound A, " whose toxicity raises concerns regarding the safe administration of sevoflurane via rebreathing circuits. In the present investigation, we measured the sevoflurane degradation and output of Compound A caused by standard (13% water) Baralyme brand absorbent and standard (15% water) soda lime, and Baralyme and soda lime having various water contents (including no water). We used a flow-through system, applying a gas flow rate relative to absorbent volume that roughly equaled the rate/volume found in clinical practice. ⋯ Both absorbents, especially when dry, also destroyed Compound A, the concentration exiting from absorbent resulting from a complex sum of production and destruction. We conclude that the variability of concentrations of Compound A found in clinical practice may be largely explained by the inflow rate used (i.e., by rebreathing), sevoflurane concentration, and absorbent temperature and dryness. The effect of dryness is complex, with fresh dry absorbent destroying Compound A as it is made, and with dry absorbent that has been exposed to sevoflurane for a period of time providing a sometimes unusually high output of Compound A.