Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1996
Comparative StudyChanges in lung and chest wall properties with abdominal insufflation of carbon dioxide are immediately reversible.
Previously we have reported that large increases in lung and chest wall elastances as well as lung resistance occur with abdominal insufflation of carbon dioxide during laparoscopic surgery. To examine whether these effects were reversible with abdominal deflation, we calculated lung and chest wall elastances and resistances from measurement of airway flow and pressure and esophageal pressure in 17 anesthetized/paralyzed patients undergoing laparoscopic surgery. Measurements were made immediately prior to abdominal insufflation and after deflation. ⋯ The change in total respiratory elastance did not correlate with abdominal insufflation time, surgical site, smoking history, or physical characteristics of the patients. There were no differences in frequency and tidal volume dependences of the elastances and resistances before and after abdominal insufflation (P > 0.5). We conclude that residual changes in respiratory mechanics caused by carbon dioxide insufflation during laparoscopic surgery are minor, and that the reported compromise of respiratory function indicated by pulmonary function tests after laparoscopy does not appear to be due to changes in passive mechanical properties of the lungs or chest wall.
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Anesthesia and analgesia · Mar 1996
Randomized Controlled Trial Clinical TrialSevoflurane versus isoflurane: induction and recovery characteristics with single-breath inhaled inductions of anesthesia.
Because of its nonpungent odor and low blood-gas solubility coefficient, sevoflurane might be an ideal drug for single-breath inhaled induction of anesthesia. Fifty ASA grade I-III ambulatory surgical patients (18-76 yr old) received a single-breath induction with either 5.0% sevoflurane or 5.0% isoflurane (randomized) in a 1:1 N2O/O2 mixture. Anesthesia was maintained with the same anesthetic in 70% N2O until the end of surgery, when anesthetics were abruptly discontinued. ⋯ Patients opened their eyes at lower end-tidal minimum alveolar anesthetic concentration (MAC)-fractions of sevoflurane (0.12 +/- 0.01 MAC) than isoflurane (0.15 +/- 0.01 MAC, P < 0.01). During recovery, patients who received sevoflurane felt less clumsy (P < 0.001) and less confused (P < 0.005) but had higher pain scores (P < 0.005) than those who received isoflurane. Sevoflurane is more suitable than isoflurane for single-breath induction, because it produces a smoother induction with a lower incidence of complications and better patient acceptance.
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Anesthesia and analgesia · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialPrevention of pain on injection of propofol: a comparison of lidocaine with alfentanil.
We undertook a randomized, placebo-controlled, double-blind study to compare the use of alfentanil 1 mg and lidocaine 40 mg for the reduction of pain during injection of propofol. Eighty-nine patients were randomly allocated to one of three groups: Group L, lidocaine 40 mg added to 180 mg propofol; Group A, alfentanil 1 mg 30 s prior to propofol; or Group P, placebo (normal saline). The incidence of pain in the placebo group was 67%. ⋯ There was no significant difference in the induction dose of propofol between the groups. Fifty-two percent of patients who experienced pain at induction had recall of that pain in the recovery room. Alfentanil 1 mg and lidocaine 40 mg are both effective in reducing pain during injection of propofol.
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Anesthesia and analgesia · Mar 1996
Comparative Study Clinical Trial Controlled Clinical TrialCost-benefit analysis of nasal cannulae in non-tracheally intubated subjects.
We evaluated four nasal cannulae used to deliver oxygen and measure PETC02 in a non-tracheally intubated, healthy population. The effect of various oxygen flow rates on PETC02 and respiratory rate (RR), as well as the cost and relative patient comfort of the cannulae, was compared. In this controlled study, 20 healthy volunteers tested the cannulae using oxygen flow rates of 0 (breathing room air), 2, 4, and 6 L/min. ⋯ Of the nasal cannula systems evaluated in this study, the HOS system demonstrated the best cost-benefit ratio, performing well clinically while being comfortable to wear and relatively inexpensive. These conclusions are specific to a healthy population and not to patients with lung disease,those who smoke, or those having a higher ASA classification status. Our evaluation suggests that comfort and clinical performance of nasal cannulae may well depend on device design.
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Anesthesia and analgesia · Mar 1996
Comparative StudyComparative electrophysiologic and hemodynamic effects of several amide local anesthetic drugs in anesthetized dogs.
Large and equipotent doses of several local anesthetics were administered in a cardiac electrophysiologic model on closed-chest dogs. Five groups of pentobarbital-anesthetized dogs were each given intravenously 16 mg/kg lidocaine, 12 mg/kg mepivacaine, 4 mg/kg or 8 mg/kg etidocaine, and 4 mg/kg bupivacaine. Lidocaine induced bradycardia, slowing of atrioventricular node conduction (AH), and marked hemodynamic depression, represented by a decrease in mean aortic pressure (MAoP), in the peak of first derivative of left ventricular pressure (LVdP/dt(max)) and by an increase in left ventricular end-diastolic pressure (LVEDP). ⋯ We conclude that mepivacaine induced moderate cardiotoxicity. In contrast, lidocaine induced dramatic hemodynamic depression while etidocaine and bupivacaine markedly impaired both electrophysiologic and hemodynamic variables. This double impairment could explain the great difficulty in resuscitating patients who have had cardiotoxic accidents induced by etidocaine or bupivacaine.