Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Multicenter Study Clinical TrialThe safety and efficacy of a fentanyl patient-controlled transdermal system for acute postoperative analgesia: a multicenter, placebo-controlled trial.
A noninvasive method of delivery of parenteral opioids for management of acute pain may offer logistic advantages for patients and nursing staff. A patient-controlled transdermal system (PCTS) under development consists of a preprogrammed, self-contained drug-delivery system that uses electrotransport technology (E-TRANS, ALZA Corp, Mountain View, CA) to deliver 40 micro g of fentanyl HCl over 10 min per on-demand dose for patient-controlled analgesia (PCA). In this randomized, double-blinded, placebo-controlled trial we compared the efficacy and safety of on-demand fentanyl HCl PCTS 40 microg against placebo for postoperative pain up to 24 h after major abdominal, orthopedic, or thoracic surgery in 205 patients. The primary efficacy measurement was the percentage of patients withdrawn from the study because of inadequate analgesia after completing at least 3 h of treatment. Secondary efficacy measures included mean pain intensity (using visual analog scales), patient global assessments, and investigator global assessments. Of 189 patients considered evaluable for efficacy, 25% of patients in the fentanyl HCl PCTS 40 microg group withdrew because of inadequate analgesia, compared with 40.4% of the placebo group (P < 0.05). Use of fentanyl HCl PCTS 40 micro g was associated with lower VAS scores and higher mean patient and investigator global assessment scores compared with placebo. No patient experienced clinically relevant respiratory depression. This study showed that a fentanyl HCl PCTS 40 microg for PCA was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery. ⋯ This multicenter, randomized, double-blinded, placebo-controlled trial showed that an on-demand fentanyl HCl patient-controlled transdermal system (PCTS) was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery. This fentanyl HCl PCTS is a preprogrammed, needle free, self-contained drug-delivery system that uses electrotransport technology (iontophoresis) to deliver 40 microg of fentanyl per on-demand dose.
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Anesthesia and analgesia · Feb 2004
Meloxicam, a specific COX-2 inhibitor, does not enhance the isoflurane minimum alveolar concentration reduction produced by morphine in the rat.
A synergistic effect of nonselective cyclooxygenase (COX) inhibitors on morphine-induced decrease of isoflurane minimum alveolar concentration (MAC(ISO)) has been observed in the rat. We studied the influence of specific COX-2 inhibitors on this decrease of MAC. Sixty-four female rats were anesthetized with isoflurane in oxygen. The animals were grouped into saline solution, aspirin (30 mg/kg), morphine (1 mg/kg), morphine (1 mg/kg) + aspirin (30 mg/kg), meloxicam (1 and 3 mg/kg), and morphine (1 mg/kg) + meloxicam (1 and 3 mg/kg). Then the MAC(ISO) was determined from alveolar gas samples at the time of tail clamp. The groups treated with saline solution, aspirin, and 1 and 3 mg/kg meloxicam did not express any statistically relevant changes among them. The administration of morphine + meloxicam 1 or 3 mg/kg significantly reduced the MAC(ISO) just as in the group where only morphine was administered (morphine 1.35% +/- 0.07%, morphine + 1 mg/kg meloxicam 1.36% +/- 0.04%, and morphine + 3 mg/kg meloxicam 1.37% +/- 0.08%). The greatest reduction of MAC(ISO) was after administration of morphine + aspirin (1.19% +/- 0.05%). The administration of meloxicam does not potentiate the morphine-induced decrease of MAC(ISO) in the rat. ⋯ A synergistic effect between morphine and aspirin on isoflurane minimum alveolar concentration has been observed in the rat--an effect that does not occur between morphine and meloxicam.
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Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Clinical TrialRapid onset of cutaneous anesthesia with EMLA cream after pretreatment with a new ultrasound-emitting device.
In this randomized, double-blinded, placebo-controlled, crossover trial of 42 human subjects, we examined the speed of onset of cutaneous anesthesia by eutectic mixture of local anesthetics (EMLA) cream after brief (approximately 10-s) pretreatment of the underlying skin with low-frequency (55 kHz) ultrasound. Four treatments were compared: ultrasound pretreatment followed by application of 1 g EMLA or placebo cream for 5 min, 10 min, 15 min, and 60 min without ultrasound pretreatment as positive control. Pain was tested by pricks with a 20 g needle. Pain scores and patient preference for EMLA or placebo cream were measured at each time point. Based on both pain scores and patient preference, cutaneous anesthesia was achieved in the EMLA groups as compared with placebo at all time points. After ultrasound pretreatment and then 5, 10, or 15 min after EMLA cream application, pain scores and overall preference were statistically indistinguishable from EMLA cream application for 60 min (without ultrasound pretreatment). There were no significant adverse effects. Low-frequency ultrasound pretreatment appears to be safe and effective in producing rapid onset of EMLA cream in this model, with results as early as 5 min. ⋯ A prospective, randomized, double-blinded, placebo-controlled clinical trial demonstrated rapid onset of cutaneous anesthesia by pretreatment of the skin with ultrasound before application of EMLA cream.
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Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Clinical TrialDoes a preemptive block of the great auricular nerve improve postoperative analgesia in children undergoing tympanomastoid surgery?
We performed a double-blinded randomized controlled trial to evaluate the efficacy of preemptive analgesia in children undergoing tympanomastoid surgery. Children were divided into two groups: group block-block (BB) received a preemptive great auricular nerve block (GAN-block) with 0.25% bupivacaine with 1:200,000 epinephrine before incision followed by a second GAN-block with 0.25% bupivacaine with 1:200,000 epinephrine 1 h before the end of the procedure. Group sham block-block (SB-B) received a preemptive GAN-block with normal saline before surgical incision followed by a GAN-block with 0.25% bupivacaine with 1:200000 epinephrine 1 h before the completion of the procedure. All patients were evaluated for pain with the objective pain score (OPS) by a blinded observer. There was no difference in pain rescue requirements in the postanesthesia care unit (BB versus SB-B, 1 of 20 versus 3 of 20, P= 0.60) or in the short-stay unit (BB versus SB-B, 5 of 20 versus 11 of 20, P = 0.107) or for the entire hospital stay (P = 0.20). There was no significant difference between groups in the time to first rescue pain medication (BB versus SB-B, 226 +/- 71 min versus 201 +/- 94 min). There was no significant difference between groups regarding vomiting in the postoperative period (P = 0.52). We conclude that a preoperative GAN-block does not offer significant advantages for postoperative pain relief in children undergoing tympanomastoid surgery. ⋯ This double-blinded randomized controlled trial compared the efficacy of preemptive analgesia with a peripheral nerve block of the great auricular nerve for decreasing postoperative pain in children undergoing tympanomastoid surgery. Preemptive analgesia did not improve the quality or duration of postoperative analgesia in our cohort.