Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of the laryngeal mask airway and cuffed oropharyngeal airway in anesthetized adult patients.
We compared the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) in 120 anesthetized adult patients. We compared 1) placement success rates, 2) airway interventional requirements, 3) airway stability in different head/neck positions, 4) cardiorespiratory tolerance, and 5) intra- and postoperative adverse events/symptoms. A standardized anesthesia protocol was followed by four anesthesiologists experienced with both devices. Observational data were validated by independent analysis of continuous video recordings. Postoperative interviews were double-blind to the device used. The LMA had a more frequent success rate than COPA (97% vs 55%, P < 0.00001), an overall higher success rate (100% vs 83%; P = 0.001), a shorter time to achieve an effective airway (49 vs 188 s; P < 0.00001), a higher oropharyngeal leak pressure (21 vs 16 cm H2O; P = 0.003), and a fewer number of chin lift airway interventions required (0.1% vs 42%; P < 0.00001). When comparing mean tidal volumes in different head/neck positions to assess airway stability, the quality of airway was unchanged in 98% patients with the LMA and 54% with the COPA (P < 0.00001). The incidences of intraoperative adverse events were similar. On removal, blood was detected more often on the COPA (3% vs 14%; P = 0.04). In the late postoperative period, more patients complained of adverse symptoms with the COPA than with the LMA (26% vs 57%; P = 0.001). Late postoperative symptoms occurred more frequently with the COPA (0.87 vs 0.34; P = 0.003). There was more late postoperative sore throat (14% vs 36%; P = 0.0003) and more jaw/neck pain (12% vs 26%; P = 0.0008) in patients managed with the COPA. This study demonstrates that the LMA offers advantages over the COPA in most technical aspects of airway management and in terms of postoperative morbidity. ⋯ In this randomized, prospective study, we compared the laryngeal mask airway and the cuffed oropharyngeal airway in anesthetized patients. The laryngeal mask airway offers advantages in most technical aspects of airway management and in terms of postoperative morbidity.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialPulmonary effects of methylprednisolone in patients undergoing coronary artery bypass grafting and early tracheal extubation.
Numerous clinical studies suggest that methylprednisolone may facilitate early tracheal extubation after cardiac surgery, yet no investigation has rigorously examined the use of the drug in this setting. In this prospective, randomized, double-blind, placebo-controlled study, we examined the pulmonary effects of methylprednisolone in patients undergoing coronary artery bypass grafting (CABG) and early tracheal extubation. Sixty patients undergoing elective CABG and early tracheal extubation were randomized into two groups. Group MP patients received i.v. methylprednisolone (30 mg/kg during sternotomy and 30 mg/kg during initiation of cardiopulmonary bypass) and Group NS patients received i.v. placebo at the same two times. Perioperative management was standardized. Alveolar-arterial (A-a) oxygen gradient, lung compliance, shunt, and dead space were determined four times perioperatively. Postoperative tracheal extubation was accomplished at the earliest appropriate time. Both groups exhibited significant postoperative increases in A-a oxygen gradient and shunt (P < 0.000001 for each group) and significant postoperative decreases in dynamic lung compliance (P < 0.000001 for each group). Patients in Group MP exhibited significantly larger increases in postoperative A-a oxygen gradient (P = 0.001) and shunt (P = 0.001) compared with patients in Group NS. Postoperative alterations in dynamic lung compliance, static lung compliance, and dead space were not statistically significant between the groups. The time to postoperative tracheal extubation was prolonged in Group MP patients compared with Group NS patients (769 +/- 294 vs 604 +/- 315 min, respectively; P = 0.05). Methylprednisolone was associated with larger increases in postoperative A-a oxygen gradient and shunt, was unable to prevent postoperative decreases in lung compliance, and prolonged extubation time, which indicate that use of the drug may hinder early tracheal extubation in patients after cardiac surgery. ⋯ Traditionally, methylprednisolone has been administered to patients undergoing cardiac surgery to decrease postoperative pulmonary dysfunction. This study revealed that the drug is associated with larger increases in postoperative alveolar-arterial oxygen gradient and shunt and prolonged tracheal extubation time in patients undergoing coronary artery bypass grafting, which indicate that use of the drug may hinder early tracheal extubation.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialPeripheral nerve blocks improve analgesia after total knee replacement surgery.
Total knee replacement (TKR) produces severe postoperative pain. Peripheral nerve blocks can be used as analgesic adjuncts for TKR, but the efficacy of femoral nerve blocks alone is controversial. The sciatic nerve innervates posterior regions of the knee; thus, performance of both sciatic and femoral nerve blocks may be necessary to improve analgesia after TKR. We performed this study to determine whether peripheral nerve blocks improve analgesia after TKR. In a randomized, double-blind fashion, 36 patients undergoing TKR received either femoral, sciatic-femoral, or sham nerve blocks after a standardized spinal anesthetic. Further postoperative analgesia was provided by patient-controlled i.v. morphine and ketorolac. Pain at rest and with physical therapy, morphine use, nausea, pruritus, sedation, and patient satisfaction were assessed. Patients receiving peripheral nerve blocks reported better analgesia at rest for at least 8 h after transfer to the hospital ward (P < 0.05). Morphine use was decreased by approximately 50% in the peripheral nerve block groups until the second postoperative day (P < 0.02). Side effect profiles and patient satisfaction were similar between groups. We conclude that femoral nerve blocks improve analgesia and decrease morphine use after TKR. The addition of a sciatic nerve block to the femoral nerve block did not further improve analgesic efficacy. ⋯ Performance of femoral nerve blocks improves analgesia and decreases the need for morphine after total knee replacement surgery. The addition of a sciatic nerve block to the femoral nerve block does not provide additional benefits.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Comparative Study Clinical TrialPreemptive caudal bupivacaine and morphine for postoperative analgesia in children.
We designed this double-blind study to evaluate the efficacy of preemptive epidural bupivacaine and small-dose morphine for postoperative analgesia in children after herniorraphy. Sixty children, ASA physical status I or II, who were undergoing elective hernia repair under general anesthesia were randomly allocated into two groups. Group I (preemptive group) received 0.66 mL/kg 0.25% bupivacaine with morphine 0.02 mg/kg caudally after the induction of anesthesia but 15 min before surgery. Group II (postincisional group) received the same drug mixture after surgery. Pain was assessed using an objective pain scale (OPS). Time to first postoperative analgesics (TFA), the number of supplementary analgesic used, and the amount of morphine consumed over the ensuing 24-h period were noted. The OPS score was significantly less in Group I at 0.5, 4, and 8 h (P < 0.05) than in Group II after surgery. The median OPS score recorded over 24 h was 0 for Group I and 2 for Group II, which was significantly different (P < 0.05). The TFA in Group I (12.55 +/- 3.06 h) was significantly (P < 0.05) prolonged compared with Group II (10.62 +/- 3.18 h). The total postoperative morphine consumption in Group I (2.24 +/- 1.4 mg) was significantly (P < 0.05) less than that in Group II (3.34 +/- 2.29 mg). Nevertheless, the incidence of nausea and vomiting was not significantly different between the groups. In this study, we demonstrated that preemptive epidural bupivacaine and small-dose morphine administration is superior to the same mixture given at the conclusion of surgery for pain relief. ⋯ This study was performed on two groups of 30 children undergoing hernia repair. Group I received a bupivacaine-morphine mixture caudally before surgery, and Group II received the same drugs caudally at the completion of surgery. Postoperative assessment demonstrated longer and better pain relief in Group I.
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Anesthesia and analgesia · Jul 1998
Tramadol reduces the sweating, vasoconstriction, and shivering thresholds.
The analgesic tramadol inhibits the neuronal reuptake of norepinephrine and 5-hydroxytryptamine, facilitates 5-hydroxytryptamine release, and activates mu-opioid receptors. Each of these actions is likely to influence thermoregulatory control. We therefore tested the hypothesis that tramadol inhibits thermoregulatory control. Eight volunteers were evaluated on four study days, on which they received no drugs, tramadol 125 mg, tramadol 250 mg, and tramadol 250 mg with naloxone, respectively. Skin and core temperatures were gradually increased until sweating was observed and then decreased until vasoconstriction and shivering were detected. The core temperature triggering each response defined its threshold. Tramadol decreased the sweating threshold by -1.03 +/- 0.67 degrees C microgram-1.mL (r2 = 0.90 +/- 0.12). Tramadol also decreased the vasoconstriction threshold by -3.0 +/- 4.0 degrees C microgram-1.mL (r2 = 0.94 +/- 0.98) and the shivering threshold by -4.2 +/- 4.0 degrees C microgram-1.mL(r2 = 0.98 +/- 0.98). The sweating to vasoconstriction interthreshold range nearly doubled from 0.3 +/- 0.4 degree C to 0.7 +/- 0.6 degree C during the administration of large-dose tramadol (P = 0.04). The addition of naloxone only partially reversed the thermoregulatory effects of tramadol. The thermoregulatory effects of tramadol thus most resemble those of midazolam, another drug that slightly decreases the thresholds triggering all three major autonomic thermoregulatory defenses. In this respect, both drugs reduce the "setpoint" rather than produce a generalized impairment of thermoregulatory control. Nonetheless, tramadol nearly doubled the interthreshold range at a concentration near 200 ng/mL. This indicates that tramadol slightly decreases the precision of thermoregulatory control in addition to reducing the setpoint. ⋯ The authors evaluated the effects of the analgesic tramadol on the three major thermoregulatory responses: sweating, vasoconstriction, and shivering. Tramadol had only slight thermoregulatory effects. Its use is thus unlikely to provoke hypothermia or to facilitate fever.