Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Comparative Study Clinical TrialSpinal 2-chloroprocaine: a comparison with lidocaine in volunteers.
Subarachnoid lidocaine has been the anesthetic of choice for outpatient spinal anesthesia. However, its use is associated with transient neurologic symptoms (TNS). Preservative-free formulations of 2-chloroprocaine are now available and may compare favorably with lidocaine for spinal anesthesia. In this double-blinded, randomized, crossover study, we compared spinal chloroprocaine and lidocaine in 8 volunteers, each receiving 2 spinal anesthetics: 1 with 40 mg 2% lidocaine and the other with 40 mg 2% preservative-free 2-chloroprocaine. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation and thigh tourniquet, motor strength, and a simulated discharge pathway were assessed. Chloroprocaine produced anesthetic efficacy similar to lidocaine, including peak block height (T8 [T5-11] versus T8 [T6-12], P = 0.8183) and tourniquet tolerance (46 +/- 6 min versus 38 +/- 24 min, P = 0.4897). Chloroprocaine anesthesia resulted in faster resolution of sensory (103 +/- 13 min versus 126 +/- 16 min, P = 0.0045) and more rapid attainment of simulated discharge criteria (104 +/- 12 min versus 134 +/- 14 min, P = 0.0007). Lidocaine was associated with mild to moderate TNS in 7 of 8 subjects; no subject complained of TNS with chloroprocaine (P = 0.0004). We conclude that the anesthetic profile of chloroprocaine compares favorably with lidocaine. Reliable sensory and motor blockade with predictable duration and minimal side effects make chloroprocaine an attractive choice for outpatient spinal anesthesia. ⋯ The spinal anesthetic profile of chloroprocaine (40 mg) compares favorably with the same dose of spinal lidocaine. Reliable sensory and motor blockade with predictable duration and minimal side effects and without signs of transient neurological symptoms make chloroprocaine an attractive choice for outpatient spinal anesthesia.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Comparative Study Clinical TrialThe efficacy of dexmedetomidine versus morphine for postoperative analgesia after major inpatient surgery.
Thirty-four patients scheduled for elective inpatient surgery were randomized equally to receive either dexmedetomidine (initial loading dose of 1- microg/kg over 10 min followed by 0.4 microg. kg(-1). h(-1) for 4 h) or morphine sulfate (0.08 mg/kg) 30 min before the end of surgery. We determined heart rate (HR), mean arterial blood pressure (MAP), respiratory rate (RR), sedation and analgesia (visual analog scale), and use of additional morphine in the postanesthesia care unit (PACU) and up to 24 h after surgery. Groups were similar for patient demographics, ASA physical status, surgical procedure, baseline hemodynamics, and intraoperative use of drugs and fluids. Dexmedetomidine-treated patients had slower HR in the PACU (by an average of 16 bpm), whereas MAP, RR, and level of sedation were similar between groups. During Phase I recovery, dexmedetomidine-treated patients required significantly less morphine to achieve equivalent analgesia (PACU dexmedetomidine group, 4.5 +/- 6.8 mg; morphine group, 9.2 +/- 5.2 mg). Sixty minutes into recovery only 6 of 17 dexmedetomidine patients required morphine in contrast to 15 of 17 in the morphine group. The administration of dexmedetomidine before the completion of major inpatient surgical procedures significantly reduced, by 66%, the early postoperative need for morphine and was associated with a slower HR in the PACU. ⋯ The use of dexmedetomidine for postoperative analgesia resulted in significantly less additional pain medication (morphine) and slower heart rates than a control group receiving only morphine. These outcomes may prove advantageous for patients who might be placed at higher risk by tachycardia or large doses of morphine.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialAntagonism of cisatracurium and rocuronium block at a tactile train-of-four count of 2: should quantitative assessment of neuromuscular function be mandatory?
With a train-of-four (TOF) ratio >0.70 as the standard of acceptable recovery, postoperative residual paralysis is a frequent occurrence in postanesthesia care units (PACUs). However, detailed information regarding prior anesthetic management is rarely provided. We examined the incidence of postoperative weakness after the administration of cisatracurium and rocuronium when using a rigid protocol for muscle relaxant and subsequent neostigmine administration. Under desflurane, N(2)O, and opioid anesthesia, tracheal intubation was accomplished after either cisatracurium 0.15 mg/kg or rocuronium 0.60 mg/kg. The response of the thumb to ulnar nerve stimulation was estimated by palpation. Additional increments of muscle relaxant were given as needed to maintain the TOF count at 1 or 2. At the conclusion of surgery, at a TOF count of 2, neostigmine 0.05 mg/kg plus glycopyrrolate 10 micro g/kg was administered. The mechanical TOF response was then measured with a force transducer starting 5 min postreversal. Patients were observed until a TOF ratio of 0.90 was achieved. There were no significant differences in the recovery profiles of cisatracurium versus rocuronium. TOF ratios at 10 min postreversal were 0.72 +/- 0.10 and 0.76 +/- 0.11, respectively. At 15 min postreversal, only one subject in each group had a TOF ratio of <0.70. No patient in either group arrived in the PACU with a TOF ratio <0.70. Our results suggest that if cisatracurium or rocuronium is administered by using the TOF count as a guide, critical episodes of postoperative weakness in the PACU should be an infrequent occurrence. ⋯ After the administration of cisatracurium or rocuronium, train-of-four (TOF) ratios <0.70 should rarely be observed in the postanesthesia care unit if neostigmine-assisted antagonism of residual block is delayed until the tactile TOF count at the thumb is 2 or more.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialPreoperative rofecoxib oral suspension as an analgesic adjunct after lower abdominal surgery: the effects on effort-dependent pain and pulmonary function.
Rofecoxib is a selective cyclooxygenase-2 inhibitor that reduces pain and inflammation without inhibiting platelet function. We examined its effects on effort-dependent pain, postoperative morphine requirements, and pulmonary function in 48 patients recovering from open abdominal surgery. Spirometric measurement of forced expiratory volume(1) and vital capacity (FVC) were assessed preoperatively. One hour before the induction of a standardized general anesthetic, patients were given either placebo oral suspension (Group A), or rofecoxib oral suspension (25 mg [Group B] or 50 mg [Group C]) in a double-blinded manner. Postoperative pain control was provided with IV morphine in the postanesthesia care unit and IV-patient-controlled analgesia morphine on the patient care unit. Morphine dose, pain intensity at rest, and pain after respiratory effort (postoperative spirometry) were assessed at 12 and 24 h after study drug administration. The patient-controlled analgesia morphine dose at 24 h was reduced 44% in Group B (30.3 +/- 17.5 mg) and 59% in Group C (22.1 +/- 16.5 mg) versus Group A (53.7 +/- 31.1 mg); P < 0.01 (A versus B). At 12 h, pain scores at rest and after spirometry were lower in Groups B and C than in A (P < 0.05). At 24 h, resting pain scores were lowest in Group C (P < 0.05). Twelve-hour FVC was best preserved in Group C (P < 0.03). There were no inter-group differences in adverse effects or perioperative blood loss. Rofecoxib oral suspension provided a morphine-sparing effect, as well as improvements in pain control and 12-h FVC in patients recovering from open abdominal surgery. ⋯ Rofecoxib belongs to class of analgesics known as cyclooxygenase-2 inhibitors that reduce pain and inflammation with less risk of bleeding than standard nonsteroidal antiinflammatory drugs. We found that patients treated with rofecoxib 25 or 50 mg before open abdominal surgery required less IV morphine during the first day of recovery. Despite reductions in morphine requirements, rofecoxib-treated patients reported lower pain intensity scores at rest and after a vigorous cough. In the 50-mg group, improvements in pain control correlated with greater preservation of baseline cough effectiveness (vital capacity) at 12 h. These findings may offer clinical advantages in patients with preexisting pulmonary disease.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialSpinal 2-chloroprocaine: the effect of added dextrose.
Spinal 2-chloroprocaine is being investigated as an alternative short-acting spinal anesthetic to replace lidocaine for outpatient surgery. Adding dextrose increases the baricity of solutions and alters the characteristics of spinal anesthesia. In this study, we compared 2-chloroprocaine spinal anesthesia performed with or without the addition of dextrose (1.1%). Eight volunteers underwent 2 spinal anesthetics, receiving 40 mg 2-chloroprocaine (2 mL, 2%) with 0.25 mL saline with one and 0.25 mL 10% dextrose with the other in a double-blinded, randomized, balanced crossover manner. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation, and tourniquet, motor strength measurements, and time to ambulation and void were assessed. Postvoid residual bladder volume was measured via ultrasound. Spinal anesthesia was successful in all subjects and regressed within 110 (80-110) min. There was no significant difference in peak height T4 (T7-C6), time to achieve peak block height (14 +/- 6 min), time for 2-segment regression (44 +/- 9 min), regression to L1 (66 +/- 12 min), tolerance of tourniquet (43 +/- 9 min), or return of motor function (81 +/- 14 min). Mean postvoid residual volume was larger with dextrose (74 +/- 67 mL versus 16 +/- 35 mL; P = 0.02). No subject reported signs of transient neurologic symptoms (TNS). In conclusion, spinal 2-chloroprocaine provides adequate potency with reliable regression, seemingly without TNS. Adding dextrose does not significantly alter spinal block characteristics but increases residual bladder dysfunction. Therefore, the addition of glucose to 2-chloroprocaine for spinal anesthesia is not necessary. ⋯ Spinal chloroprocaine provides adequate potency with reliable regression, seemingly without concerns of transient neurologic symptoms, and hence an appealing profile for outpatient surgery. The addition of dextrose does not alter peak block height or tolerance of thigh tourniquet, and increases the degree of residual bladder dysfunction.