Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialAdding ketamine in a multimodal patient-controlled epidural regimen reduces postoperative pain and analgesic consumption.
We designed this double-blind study to evaluate the effect of adding small-dose ketamine in a multimodal regimen of postoperative patient-controlled epidural analgesia (PCEA). Ninety-one patients, ASA physical status I-III, undergoing major surgery, received a standardized general anesthesia and epidural catheterization in an appropriate intervertebral space after surgery. A PCEA device was programmed to deliver a regimen of morphine 0.02 mg/mL, bupivacaine 0.8 mg/mL, and epinephrine 4 microg/mL, with the addition of ketamine 0.4 mg/mL (ketamine, n = 45) or without (control, n = 46). The mean visual analog pain scale (VAS) scores during cough or movement for the first 3 days after surgery were higher in the control group than in the ketamine group (P < 0.05), whereas the mean VAS score at rest for the first 2 days were higher in the control group than in the ketamine group (P < 0.05). Furthermore, patients in the control group consumed more multimodal analgesics than patients in the ketamine group for the first 2 days (P < 0.05). The sedation scores and the incidence of side effects (pruritus, nausea, emesis, sleep deprivation, motor block, and respiration depression) were similar between the two groups. We conclude that adding ketamine 0.4 mg/mL in a multimodal PCEA regimen provides better postoperative pain relief and decreases consumption of analgesics. ⋯ Many studies have evaluated one or a combination of two analgesics for postoperative pain control, but few have examined a multimodal approach using three or four different epidural analgesics. This study demonstrates an additive analgesic effect when ketamine is added to a multimodal analgesic treatment.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Comparative Study Clinical TrialAnalgesic and cognitive effects of intravenous ketamine-alfentanil combinations versus either drug alone after intradermal capsaicin in normal subjects.
Combinations of opioids and N-methyl-D-aspartate (NMDA) antagonists enhance acute antinociception and reduce opioid tolerance in some animal experiments but have received little rigorous study in humans. To quantitatively assess the nature of the interaction of these two classes of drugs in producing analgesia and cognitive impairment, we compared i.v. infusions of ketamine, alfentanil, and ketamine-alfentanil combinations in 12 normal volunteers after an intradermal injection of capsaicin. Drug doses for a 70-kg subject in this six-session, randomized, double-blind, cross-over study were: ketamine 20 mg, ketamine 5 mg, alfentanil 2 mg, alfentanil 0.5 mg, ketamine 10 mg + alfentanil 1 mg, and ketamine 2.5 mg + alfentanil 0.25 mg, given over 35 min. Outcome measures were background pain, area and magnitude of hyperalgesia to pinprick, and cognitive performance on the Digit Symbol Substitution Test and the Perception Speed Test. The results demonstrated simple additivity for the effects of ketamine and alfentanil on pain, pinprick hyperalgesia, and cognitive impairment. We conclude that, at least in this experimental pain model, there is no clear advantage or disadvantage of a ketamine-alfentanil combination over equianalgesic doses of either component. ⋯ In a double-blind, controlled trial, we administered doses of an opioid analgesic (alfentanil), an N-methyl-D-aspartate receptor antagonist (ketamine), or their combination to normal volunteers and found no advantage of the combination over a larger dose of either drug alone in relieving pain caused by painful chemical stimulation.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Comparative Study Clinical TrialBronchial mucus transport velocity in paralyzed anesthetized patients: a comparison of the laryngeal mask airway and cuffed tracheal tube.
We compared bronchial mucus transport velocity (BTV), an index of mucociliary clearance, between the laryngeal mask airway (LMA) and the tracheal tube (TT). Forty patients were studied during propofol anesthesia and muscle relaxation with rocuronium. BTV was measured 10 and 60 min after insertion of the airway device by fiberoptic observation of the movement of methylene blue dye injected onto the dorsal surface of the left main bronchus. BTV for the LMA was similar at 10 and 60 min (13.9 +/- 2.0 and 13.6 +/- 2.1 mm/min, respectively). BTV for the TT was significantly faster at 10 min that at 60 min (13.0 +/- 1.4 vs 6.9 +/- 1.2 mm/min, respectively; P < 0.00001). BTV was similar for both devices at 10 min (TT 13.0 +/- 1.4 mm/min versus LMA 13.9 +/- 2.0 mm/min), but was significantly faster for the LMA than for the TT at 60 min (LMA 13.6 +/- 2.1 mm/min versus TT 6.9 +/- 1.2 mm/min; P < 0.00001). We conclude that the LMA impedes mucociliary clearance less than the TT in anesthetized patients. This may have implications for reducing the risk of retention of secretions, atelectasis, and pulmonary infection. ⋯ This study compares bronchial mucus transport velocity, an index of mucociliary clearance, in anesthetized patients between two airway devices, the cuffed tracheal tube and the laryngeal mask airway. We have shown that the laryngeal mask airway impairs mucociliary clearance less than the tracheal tube. This may have implications for reducing the risk of retention of secretions, atelectasis, and pulmonary infection.