Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Multicenter Study Clinical TrialThe potency (ED50) and cardiovascular effects of rapacuronium (Org 9487) during narcotic-nitrous oxide-propofol anesthesia in neonates, infants, and children.
We studied the neuromuscular blocking effects of rapacuronium (Org 9487) (dose-response curve, onset, and 50% effective dose [ED50] value), and changes in heart rate and blood pressure, as well as evidence of histamine release in neonates, infants, and children in an open-label, randomized, two-center study. Fifteen neonates, 30 infants, and 30 children were studied. Anesthesia was induced and maintained with propofol, nitrous oxide:oxygen (60:40), and fentanyl. Mechanomyographic monitoring of neuromuscular function was performed at the thumb. The potency (ED50) for neonates, infants, and children were 0.32 (95% confidence interval [CI] 0.15-0.61), 0.28 (95% CI 0.11-0.61), and 0.39 (95% CI 0.17-0.85) mg/kg, respectively. Neonates who received 0.3, 0.6, or 0.9 mg/kg Org 9487 developed a maximum T1 twitch depression of 34 +/-28%, 98 +/- 3%, and 99 +/- 2%, respectively. Time-to-peak effect (onset time) for 0.9 mg/kg Org 9487 was 57 +/- 20 s. Maximum percent T1 twitch depression (+/-SD) in infants who received 0.3, 0.6, or 0.9 mg/kg rapacuronium was 41 +/- 34%, 96 +/- 7%, and 100 +/- 1%, respectively. Time-to-peak effect for 0.9 mg/kg Org 9487 was 62 +/- 29 s. In children 0.3, 0.6, and 0.9 mg/kg rapacuronium resulted in an average percent T1 twitch suppression of 29 +/- 23, 83 +/- 11, and 90 +/- 16, respectively. Time-to-peak effect of 0.9 mg/kg Org 9487 was 96 +/- 33 s, respectively. There was no evidence of histamine release or significant changes in heart rate or blood pressure in either group at any dose. Rapacuronium is a low-potency nondepolarizing muscle relaxant with a fast onset of relaxation and minimal cardiovascular effects. Its potency (ED50) is similar in neonates (0.32 mg/kg), infants (0.28 mg/kg), and children (0.39 mg/kg). T1 suppression (90% +/- 16) is less and time to peak effect (96 +/- 33 s) is greater (0.9 mg/kg rapacuronium) in children, compared with the combined group of infants and neonates. ⋯ This study assesses the potency of rapacuronium (Org 9487) in pediatric patients. The potency of rapacuronium is similar in neonates (0.32 mg/kg), infants (0.28 mg/kg), and children (0.39 mg/kg).
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialTwo doses of intrathecal sufentanil (2.5 and 5 microg) combined with bupivacaine and epinephrine for labor analgesia.
In this study, we evaluated the effect of two doses of intrathecal sufentanil combined with bupivacaine and epinephrine on the incidence of pruritus and on the duration and quality of analgesia. One hundred five parturients were enrolled in this randomized, double-blinded, placebo-controlled study. They received either intrathecal 1.25 mg bupivacaine and 25 microg epinephrine (control group); 1.25 mg bupivacaine, 25 microg epinephrine, and 2.5 microg sufentanil (2.5-microg group); or 1.25 mg bupivacaine, 25 microg epinephrine, and 5 microg (5-microg group). Pain relief was assessed 10 min after injection, and pruritus was recorded at 30 min by a blinded observer. The study ended when the parturients requested further analgesia. There were no demographic differences among groups. Ninety of 103 parturients achieved complete pain relief with the initial dose, 11 patients in the control group (P < 0.004, control versus both sufentanil groups), and 2 patients in the 2.5-microg group needed a supplemental epidural bupivacaine. Pruritus was absent in the control group (P < 0.0001, control versus both sufentanil groups), whereas it was present in 36% of the 2.5-microg group and in 66% of the 5-microg group (P = 0.015, 2.5-microg versus 5-microg group). The mean duration of analgesia was similar in patients receiving sufentanil (2.5-microg group: 133 +/- 55 min; 5-microg group: 142 +/- 52 min) but was significantly higher than the control group (56 +/- 32 min). Reducing the sufentanil dose from 5 microg to 2.5 microg when combined with bupivacaine and epinephrine, decreases the incidence of pruritus without impeding the quality or duration of analgesia. ⋯ We evaluated two different doses of intrathecal sufentanil combined with bupivacaine and epinephrine for labor analgesia. Sufentanil 2.5 microg offered an advantage over sufentanil 5 microg because, while providing the same quality and duration of analgesia, it was associated with a reduced incidence of pruritus.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialInterscalene brachial plexus analgesia after open shoulder surgery: continuous versus patient-controlled infusion.
In this prospective, randomized, double-blinded study, we assessed the efficacy of patient-controlled analgesia (PCA) for continuous interscalene analgesia after open shoulder surgery. Sixty patients were divided into three groups of 20. During a 48-h period, they received, via an interscalene catheter, a continuous infusion of 0.125% bupivacaine with sufentanil 0.1 microg/mL and clonidine 1 microg/mL at 10 mL /h in Group 1; a continuous infusion of the same solution at 5 mL/h plus PCA boluses (2.5 mL/30 min) in Group 2; and only PCA boluses (5 mL/30 min) of the same solution in Group 3. Pain scores, sensory block, supplemental analgesia, bupivacaine consumption, side effects, and satisfaction scores were recorded. At 24 and 48 h, sensory block was more frequent and pain control was significantly better in Groups 1 and 2 than in Group 3 (P < 0.001). In Group 3, larger doses of paracetamol were required. Bupivacaine consumption was significantly less in Groups 2 and 3 than in Group 1 (P < 0.001). Satisfaction was significantly higher in Groups 1 and 2 than in Group 3 (P < 0.01). Side effects were comparable in the three groups. We conclude that continuous interscalene analgesia requires a background infusion after open shoulder surgery. Because it reduces the local anesthetic consumption and allows the patients to rapidly reinforce the block shortly before physiotherapy, a basal infusion rate of 5 mL/h combined with PCA boluses (2.5 mL/ 30 min) is the recommended technique. ⋯ In this study, we demonstrated that continuous interscalene analgesia requires a background infusion to provide efficient pain relief after open shoulder surgery. A basal infusion of 5 mL/h combined with patient-controlled analgesia boluses (2.5 mL/30 min) seems to be the most appropriate technique.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialAttempting to maintain normoglycemia during cardiopulmonary bypass with insulin may initiate postoperative hypoglycemia.
We attempted to develop an insulin administration protocol that maintains normoglycemia in patients undergoing cardiac surgery and to study the effects of intraoperative blood glucose management on serum levels of creatine phosphokinase isoenzyme BB (CK-BB) and S-100 protein. Twenty nondiabetic patients were randomly allocated to receive either "tight control" of blood glucose with a standardized IV insulin infusion intraoperatively (Group TC) or "no control" of blood glucose intraoperatively (Group NC). Perioperative serum levels of glucose, CK-BB, and S-100 protein were determined in all patients. Group TC patients received 90.0 +/- 49.2 units of insulin, whereas Group NC patients received none. Despite insulin, both Group TC (P = 0.00026) and Group NC (P = 0.00003) experienced similar significant increases in blood glucose levels during hypothermic cardiopulmonary bypass. However, mean blood glucose level upon intensive care unit arrival was significantly decreased in Group TC, compared with Group NC (84.7 +/- 41.0 mg/dL, range 32-137 mg/dL vs 201.4 +/- 67.5 mg/dL, range 82-277 mg/dL, respectively; P = 0.0002). Forty percent of Group TC patients required treatment for postoperative hypoglycemia (blood glucose level <60 mg/dL). Substantial interindividual variability existed in regard to insulin resistance. The investigation was terminated after we realized that normoglycemia was unattainable with the study protocol and that postoperative hypoglycemia was unpredictable. All patients in both groups experienced similar significant increases in postoperative serum levels of CK-BB and S-100 protein. These results indicate that "tight control" of intraoperative blood glucose in nondiabetic patients undergoing cardiac surgery was unattainable with the study protocol and may initiate postoperative hypoglycemia. ⋯ The appropriate intraoperative management of hyperglycemia and whether it adversely affects neurologic outcome in patients after cardiac surgery remains controversial. This investigation reveals that attempting to maintain normoglycemia in this setting with insulin may initiate postoperative hypoglycemia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe effect of midazolam premedication on mental and psychomotor recovery in geriatric patients undergoing brief surgical procedures.
To assess the effect of IV midazolam premedication on recovery of cognitive function, 90 geriatric patients (aged 65-81 yr) undergoing brief transurethral procedures were enrolled into this prospective, placebo-controlled, double-blinded study. In all cases, a standard general anesthetic was administered. Thirty minutes before operating room transfer, patients in Group 0.5 mg, Group 2 mg, and Group S received 0.5 mg of midazolam, 2 mg of midazolam, or an equal volume of saline, respectively. Before study-drug administration (baseline), at 15 min thereafter, as well as on arrival in the postanesthesia care unit (PACU), and at 60 min and 120 min, postoperatively, we administered a digit-symbol substitution test, a mini-mental test, a shape-sorter test, and a patient-generated 100-mm visual analog score (0 = minimal and 100 = maximal) for anxiety, sleepiness, and coordination. A 4-point scale was used to assess the degree of patient sedation at 7, 15, and 30 min after study-drug administration. Using a modified Aldrete scoring system, PACU discharge was determined by the PACU staff. Patient anxiety, sleepiness, and coordination scores at baseline and at 15 min after study-drug administration were similar. When compared with saline, midazolam was associated with a significantly (P < 0.05) higher incidence of "deep" sedation. In Group 2 mg, the incidence of a low preoperative Spo2 (<94%) was significantly (P < 0.05) higher when compared with Group S. Emergence, extubation, and orientation times, as well as time to follow commands were unaffected by midazolam premedication. Postoperatively, the digit-symbol substitution test, mini-mental test, and shape-sorter test were similar among the groups. However, time to PACU discharge was significantly (P = 0.03) longer in the two midazolam treatment groups (41 +/-25 min, 60 +/- 32 min, 53 +/- 39 min for Groups S, 0.5 mg, and 2 mg, respectively). Finally, patient satisfaction was unaffected by the randomization schedule. ⋯ IV premedicant midazolam 0.5 mg or 2 mg does not adversely affect mental and psychomotor recovery in geriatric patients undergoing brief surgical procedures. However, midazolam administration significantly prolonged postanesthesia care unit discharge time. Finally, during the preoperative period, midazolam increases the incidence of a Spo2 <94% in a dose-dependent manner.