Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1992
Comparative StudyQuantification of the jet function of a jet stylet.
The concept and use of a jet stylet as an additional safety measure during tracheal extubation of patients in whom subsequent ventilation and/or reintubation of the trachea may be difficult has recently been described. If jet ventilation through a jet stylet could provide for effective gas exchange, it would allow additional time to assess the need for reintubation of the trachea. We determined the tidal volumes (measured by integrating a pneumotachograph flow signal) that 50-psi jet ventilation, at an inspiratory to expiratory time ratio of 1:1 (unit of time = 1 s), could deliver through small, medium, and large Sheridan tube exchangers into an in vitro lung model that had lung compliances of 50 and 30 mL/cm H2O (six experimental permutations). ⋯ Decreased lung compliance caused decreased VT and end-expiratory volume for all six experimental conditions. The largest VT and minute ventilation (VE) generated were 1680 mL and 51.6 L/min (large tube exchanger, high lung compliance) and the lowest VT and VE were 440 mL and 13.2 L/min (small tube exchanger, low lung compliance), respectively. These findings validate the term "jet stylet" for all three tube exchangers as even the smallest tube exchanger, coupled with a low lung compliance, can provide a VE consistent with total ventilatory support for most clinical situations.
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Anesthesia and analgesia · Apr 1992
Enhancement of bupivacaine sensory blockade of rat sciatic nerve by combination with phenol.
We sought to determine whether the addition of phenol would enhance a bupivacaine nerve block. The effects on nerve conduction of bupivacaine (0.125%) and phenol (0.5%), singly and combined, were evaluated in vivo on the rat sciatic nerve. Three groups of 10 animals each were used. ⋯ The analgesia score derived from the hot-plate test was more and persisted longer for the combination treatment than for either 0.125% bupivacaine or 0.5% phenol given singly; e.g., the average sensory block score after 150 min for the combination treatment was 1.0 compared with 0.1 for either bupivacaine or phenol given alone (P = 0.003). Analysis of the areas under the sensory score-time curves also demonstrated enhanced blockade from the combination treatment, which would be consistent with a synergism of the separate Na(+)-channel blocking effects of charged and uncharged local anesthetics. These findings may suggest other candidates for clinically useful combinations of amine and neutral local anesthetics.
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Anesthesia and analgesia · Apr 1992
Randomized Controlled Trial Comparative Study Clinical TrialSubhypnotic doses of propofol possess direct antiemetic properties.
Propofol is associated with a low incidence of postoperative nausea and vomiting. In a prospective, randomized, double-blind, placebo-controlled study, we investigated the possible direct antiemetic properties of a subhypnotic dose of propofol. Fifty-two ASA physical status I or II patients, aged 15-60 yr with nausea and vomiting after minor gynecologic, orthopedic, or digestive tract surgery, were included in the study and received either propofol (10 mg = 1 mL) or placebo (1 mL Intralipid) intravenously in the postanesthesia care unit. ⋯ Hemodynamic values remained unchanged in both groups. Pain on injection (7.6%) or dizziness (3.6%) only occurred in the propofol group. We conclude that propofol has significant direct antiemetic properties.
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Anesthesia and analgesia · Apr 1992
Randomized Controlled Trial Comparative Study Clinical TrialA comparative study of transdermal 10% lidocaine gel with and without glycyrrhetinic acid monohemiphthalate disodium for pain reduction at venous cannulation.
The clinical benefits of transdermal 10% lidocaine base gels with and without 3% glycyrrhetinic acid monohemiphthalate disodium (GAMHPh) for reduction of pain at venous cannulation were compared in a randomized, double-blind fashion in 24 surgical patients. After about 60 min of occlusive transdermal application, the mean pinprick pain score (1.3 +/- 1.5) in the GAMHPh group (n = 12), graded by noting the number of painful pinpricks out of five, was significantly less than that (2.5 +/- 1.7) in the control group (n = 12) (P less than 0.05). ⋯ Erythema observed in 8 of the 24 patients was the only adverse local reaction. Addition of 3% GAMHPh to the lidocaine gel is useful in promoting transdermal lidocaine absorption.