Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialDo laryngeal mask airway devices attenuate liquid flow between the esophagus and pharynx? A randomized, controlled cadaver study.
In this randomized, controlled cadaver study, we tested the hypothesis that the standard laryngeal mask airway (LMA) and flexible laryngeal mask airway (FLMA) attenuate liquid flow between the esophagus and pharynx. Fifty fresh cadavers were studied in four LMA groups. Ten female cadavers had a size 4 LMA and 10 had a size 4 FLMA; 10 male cadavers had a size 5 LMA and 10 had a size 5 FLMA; 5 male and 5 female cadavers functioned as controls. The chest was opened, and the infusion set of a pressure-controlled, continuous flow pump was inserted into the esophagus and ligated into place. Esophageal pressure was increased in 2-cm H2O increments. Regurgitation pressure was the esophageal pressure at which fluid was first seen with a fiberoptic scope in the hypopharynx (control group) and above the cuff or within the bowl (LMA groups). This was performed in the LMA groups at 0-40 mL cuff volume in 10-mL increments. Mean (95% confidence interval) regurgitation pressure for the control group was 7 (6-8) cm H2O and for the LMA groups combined was 19 (17-20) cm H2O at 0 mL cuff volume, 47 (41-52) cm H2O at 10 mL, 51 (44-55) cm H2O at 20 mL, 52 (45-56) cm H2O at 30 mL, and 52 (45-55) cm H2O at 40 mL. The increase in regurgitation pressure with increasing cuff volume from 0 to 10 mL was statistically significant (P < 0.0001). Regurgitation pressure was higher for the LMA groups at all cuff volumes compared with the control group (P < 0.0001). There were no differences in regurgitation pressure among the LMA groups. We conclude that the correctly placed LMA and FLMA attenuate liquid flow between the esophagus and pharynx. ⋯ We have shown, in cadavers, that the correctly placed standard and flexible laryngeal mask airways attenuate liquid flow between the pharynx and esophagus.
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Anesthesia and analgesia · Apr 1999
ReviewAlcohol withdrawal in the surgical patient: prevention and treatment.
In the literature on AWS, there is repeated emphasis on performing a thorough preanesthesia assessment in patients with suspected chronic alcohol use. Because these patients are difficult to diagnose and to treat in surgical settings if complications arise, a multimodal approach is highly recommended (86). Ideally, AWS should be prevented by adequate prophylaxis. ⋯ The drug regimens must be individualized and symptom-oriented to treat hallucinations and autonomic signs. Dosages are generally larger than those in detoxification units. Other approaches to modulate the neuroendocrine-immune axis in patients with an increased risk of postoperative infectious complications look promising but await controlled trials.
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Anesthesia and analgesia · Apr 1999
Clinical TrialA dose-response study of intravenous regional anesthesia with meperidine.
Intravenous regional anesthesia (IVRA) with meperidine in doses > or = 100 mg provides effective postoperative analgesia. However, this technique is associated with excessive opioid-related side effects, which limit its clinical usefulness. The minimal dose of meperidine that is effective for IVRA has yet to be established. We added 0, 10, 20, 30, 40, or 50 mg of meperidine to 0.5% lidocaine IVRA for either carpal tunnel or tenolysis surgery. Pain and sedation scores and the incidence of side effects were assessed in the postanesthesia care unit. The duration of analgesia, defined as the time to first request for pain medications, and use of acetaminophen/codeine (T3) tablets were measured. The duration of analgesia increased, in a dose-dependent manner, in the groups that received 0, 10, 20, and 30 mg of meperidine. There was no significant difference in the duration of analgesia for patients receiving > or = 30 mg of meperidine. T3 use was similar in the groups that received 0, 10, and 20 mg of meperidine and in the groups that received 30, 40, and 50 mg. T3 use was significantly lower in the larger dose groups. The incidence of sedation and of all other side effects was significantly higher in the groups that received 30-50 mg of meperidine compared with those that received smaller doses. We conclude that doses of meperidine large enough to produce the most effective postoperative analgesia with IVRA lidocaine causes a significant incidence of side effects, thus limiting its clinical usefulness. ⋯ Meperidine may be a useful addition to 0.5% lidocaine for i.v. regional anesthesia. We showed that 30 mg is the optimal dose of meperidine with respect to postoperative analgesia. However, this dose caused a significant incidence of sedation, dizziness, and postoperative nausea and vomiting.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialUse of remifentanil during anesthetic induction: a comparison with fentanyl in the ambulatory setting.
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Anesthesia and analgesia · Apr 1999
Isoflurane and sodium nitroprusside reduce the depressant effects of protamine sulfate on isolated ischemic rat hearts.
The administration of protamine sulfate (protamine) to reverse the action of heparin is associated with adverse reactions. We studied the effects of protamine and isoflurane on isolated, perfused rat hearts previously subjected to cardioplegic ischemia. Hearts were perfused with oxygenated Krebs-Henseleit (KH) solution for 30 min, then subjected to cardioplegic ischemia for 30 min (KCl 16 mEq/L at 31 degrees C) and 5 min reperfusion. Drug exposure lasted 15 min, and the recovery period was 60 min. Test groups were control, protamine (10 microg/mL), isoflurane (1.5%), protamine +/- isoflurane, sodium nitroprusside (SNP) (2.5 ng/mL), and SNP +/- protamine. Left ventricular developed pressure (LVP), coronary flow, and myocardial oxygen consumption were depressed by protamine to 30% +/- 4%, 47% +/- 4%, and 39% +/- 4% of baseline (P < 0.001 versus control), respectively. Isoflurane and SNP afforded partial protection from the effects of protamine: LVP was 57% +/- 5% and 51% +/- 3% of baseline, respectively (P < 0.05 versus protamine alone and control); coronary flow was 70% +/- 6% and 97% +/- 12% of baseline, respectively (P < 0.05 versus protamine alone; P < 0.05 for isoflurane versus control); and O2 consumption was 69% +/- 6% and 88% +/- 15% of baseline, respectively (P < 0.05 versus protamine; P < 0.05 for isoflurane versus control). In this model, protamine-induced myocardial depression and coronary vasoconstriction were less pronounced in the presence of either isoflurane or SNP. ⋯ We examined the interactions of isoflurane, sodium nitroprusside, and protamine in a rat heart model and found that both isoflurane and sodium nitroprusside partially protect the heart from the depressant effects of protamine. This finding is significant, as these drugs are often used in heart surgery.