Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1997
Peripherally administrated morphine attenuates capsaicin-induced mechanical hypersensitivity in humans.
We examined the hypothesis that peripheral morphine can modulate pain and hyperalgesia/allodynia in the human capsaicin model. Subcutaneous injections of 1 mL morphine (1 mg/mL) in one arm and of 1 mL 0.9% saline in the other arm were made prior to bilateral intradermal injections of 50 microL (6 mg/mL) capsaicin. All injections were made on the volar aspect of the arm. ⋯ Capsaicin injection resulted in spontaneous pain on the saline-injected side not significantly different from that on the morphine-injected side. However, capsaicin injections gave rise to significantly less pain evoked by mechanical stimuli, as well as to a significantly smaller area of mechanical hypersensitivity, on the morphine-injected side compared with the saline-injected side. These results suggest that morphine can modulate sensitization mechanisms involved in the development of capsaicin-induced mechanical hypersensitivity.
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The incidence of difficulty in tracheal intubation in the presence of goiter was investigated. Data were collected in a series of 4742 consecutive adult patients undergoing general anesthesia. The prevalence of goiter was 6.8%. ⋯ There was no difference in probability of difficulty in tracheal intubation between patients who presented for thyroidectomy and patients with goiter estimated as a random finding. Statistical analysis revealed an increased risk of difficult intubation amongst goiter patients compared with patients with no evidence of any risk factor (6.8% vs 0.9%, P < 10(-8), relative risk = 7.4). We conclude that goiter, when accompanied by airway deformity, constitutes an aggravating factor for difficult intubation.
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Anesthesia and analgesia · Mar 1997
The relaxant effect of ketamine on guinea pig airway smooth muscle is epithelium-independent.
Airway epithelial cells and vascular endothelial cells modulate the tone of the underlying smooth muscle by releasing relaxing factors such as prostanoids and nitric oxide (NO). In the present study, we investigated whether the relaxant effect of ketamine depends on any of the epithelium-derived relaxing factors. Tracheae of female guinea pigs were cut spirally into strips (15 x 3 mm) and mounted in water-jacketed organ baths filled with Krebs-bicarbonate buffer aerated with a mixture of 95% O2 and 5% CO2 at 37 degrees C. ⋯ L-NAME did not influence the relaxant effect of ketamine on tracheae contracted by either histamine (the IC50 of ketamine = 1.6 +/- 0.05 x 10(-3) M in control strips and 1.6 +/- 0.05 x 10(-3) M in strips pretreated with L-NAME, P > 0.05) or carbachol (the IC50 of ketamine = 2.6 +/- 0.04 x 10(-4) M in control strips and 2.3 +/- 0.01 x 10(-4) M in trips pretreated with L-NAME, P > 0.05). These results indicate that neither the mechanical removal of the tracheal epithelium nor the blockade of the release of potent mediators from tracheal epithelial cells influence the relaxant effect of ketamine on guinea pig tracheal strips contracted by histamine or carbachol. We conclude that ketamine relaxes the airway smooth muscle by an epithelium-independent mechanism.
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Anesthesia and analgesia · Feb 1997
Randomized Controlled Trial Clinical TrialIntrathecal morphine for coronary artery bypass grafting and early extubation.
Aggressive control of pain during the immediate postoperative period after cardiac surgery with early tracheal extubation may decrease morbidity and mortality. This prospective, randomized, double-blinded, placebo-controlled clinical study examined the use of intrathecal morphine in patients undergoing cardiac surgery and its influence on early tracheal extubation and postoperative analgesic requirements. Patients were randomized to receive either 10 micrograms/kg of intrathecal morphine (n = 19) or intrathecal placebo (n = 21). ⋯ Although mean postoperative IV morphine use for 48 h was less in patients who received intrathecal morphine (42.8 mg) when compared to patients who received intrathecal placebo (55.0 mg), the difference between groups was not statistically significant. In conclusion, intrathecal morphine offers promise as a useful adjunct in controlling postoperative pain in patients after cardiac surgery. However, the optimal dose of intrathecal morphine in this setting, along with the optimal intraoperative baseline anesthetic that will provide significant analgesia, yet not delay extubation in the immediate postoperative period, remains to be elucidated.
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Anesthesia and analgesia · Feb 1997
Randomized Controlled Trial Multicenter Study Clinical TrialIntravenous dolasetron for the prevention of postoperative nausea and vomiting after outpatient laparoscopic gynecologic surgery.
The newer 5-hydroxytryptamine type 3 (5-HT3) antagonists are sometimes considered for routine prophylaxis of postoperative nausea and vomiting (PONV) in high-risk patients. This multicenter, randomized, double-blind, placebo-controlled study compared the efficacy and safety of three single intravenous (IV) doses of dolasetron mesylate salt (12.5, 25, or 50 mg) for the prevention of PONV in 635 females undergoing outpatient laparoscopic gynecologic surgery. Antiemetic efficacy was evaluated over a 24-h postoperative period by recording the number and timing of emetic episodes; effects on nausea were evaluated by a visual analog scale (VAS). ⋯ Dolasetron-treated patients had significantly (P < 0.0357) lower median postdose maximum nausea VAS scores compared with placebo-treated patients. Patient satisfaction with dolasetron was high and, overall, was significantly (P = 0.0131) greater than that with placebo. Dolasetron was an effective and well tolerated preventive treatment for PONV resulting from laparoscopic gynecologic surgery.