Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialComparison of sevoflurane with propofol for laryngeal mask airway insertion in adults.
We performed a prospective, randomized, controlled trial to compare the quality and ease of laryngeal mask airway (LMA) insertion after either rapid inhaled sevoflurane or i.v. propofol induction of anesthesia. Seventy-six unpremedicated ASA physical status I or II patients were anesthetized with either a single vital capacity breath of sevoflurane 8% or i.v. propofol 3 mg/kg, which produced equally rapid loss of consciousness (40.5 +/- 13.9 vs 37.7 +/- 9.9 s; P > 0.05). The LMA was inserted more rapidly in patients in the propofol group (74 +/- 29 vs 127 +/- 35 s; P < 0.01) and required fewer attempts (1.2 vs 1.6; P < 0.05) than the sevoflurane group. There was a greater incidence of initially impossible mouth opening in the sevoflurane group (45% vs 21%; P < 0.05). Once mouth opening was possible, the degree of attenuation of laryngeal reflexes was similar. The overall incidence of complications related to LMA insertion, especially apnea (32% vs 0%; P < 0.01), was more frequent in the propofol group (82% vs 26%; P < 0.01). There were four failures of LMA insertion in the propofol group and none in the sevoflurane group. Both groups had stable hemodynamic profiles and good patient satisfaction. We conclude that sevoflurane vital capacity breath induction compares favorably with i.v. propofol induction for LMA insertion in adults. However, prolonged jaw tightness after the sevoflurane induction of anesthesia may delay LMA insertion. ⋯ In this randomized, controlled trial, we compared the ease of insertion of the laryngeal mask airway in adults after induction of anesthesia with either a sevoflurane vital capacity breath technique or propofol i.v.. We conclude that sevoflurane compares favorably with propofol, although prolonged jaw tightness may delay laryngeal mask airway insertion.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialThe effects of three graded doses of meperidine for spinal anesthesia in African men.
The intrathecal injection of 0.7-1 mg/kg meperidine provides spinal anesthesia of only short duration. In this study, we investigated the effects of three different doses of meperidine for spinal anesthesia on the duration and level of sensory block and the incidence of side effects. Forty-five African men were randomly allocated to receive one of three doses of intrathecal meperidine: Group A = 1.2 mg/kg, Group B = 1.5 mg/kg, and Group C = 1.8 mg/kg. The duration of sensory block was significantly longer after 1.5 mg/kg compared with 1.2 mg/kg meperidine (112 +/- 19 vs 79 +/- 27 min; P = 0.001). Increasing the dose to 1.8 mg/kg did not further increase the duration of block. The level and the onset of the block were not affected by the dose. Common side effects were fatigue (27%), pruritus (20%), and nausea (7%). Seven patients had respiratory depression and seven had a decrease of systolic arterial blood pressure (SAP) >30% from baseline. There was no difference in the incidence of any side effect among groups. Respiratory depression and decreases in SAP were observed 5-50 min after meperidine injection. Twenty-two patients had no pain after the sensory block had terminated. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects. ⋯ Intrathecal meperidine 1 mg/kg provides surgical anesthesia for only 40-90 min. We investigated the effects of three larger doses of meperidine in 45 African men. The 1.5 and 1.8 mg/kg doses provide a longer duration of anesthesia compared with 1.2 mg/kg. Nausea, pruritus, and respiratory depression were common in all dose groups. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of epidural ropivacaine infusion alone and in combination with 1, 2, and 4 microg/mL fentanyl for seventy-two hours of postoperative analgesia after major abdominal surgery.
Our aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness and side effects of epidural infusions with ropivacaine 2 mg/mL alone (Group R; n = 60) and in combination with fentanyl 1 microg/mL (R1F; n = 59), 2 microg/mL (R2F; n = 62), and 4 microg/mL (R4F; n = 63) for up to 72 h after major abdominal surgery. Effective epidural neural blockade was established before surgery; postoperatively, the infusion rate was titrated to a maximum of 14 mL/h for analgesia. No additional analgesics other than acetaminophen were permitted during the infusion. The median of individual visual analog scale score with coughing were <20 mm for all groups (0 = no pain, 100 = worst pain) and was significantly lower (P < 0.01) for Group R4F at rest and with coughing (compared with Group R). Infusions were discontinued due to inability to control pain in significantly fewer patients in Group R4F (16%) than the other groups (34% to 39%; P < 0.01). For all groups, >90% of patients had no detectable motor block after 24 h. Hypotension, nausea, and pruritus were more common with the larger dose of fentanyl. We conclude that, after major abdominal surgery, an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL provided significantly more effective pain relief over a 3-day period than ropivacaine alone or ropivacaine with lower concentrations of fentanyl. ⋯ Postoperative epidural analgesic infusions are widely used, but there is little information regarding optimal strengths of opioid with local anesthetic. In this blinded, prospective study, we compared four different epidural infusion solutions for efficacy and side effects over a clinically useful postoperative period and conclude that an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL was most effective.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe epidural "top-up" in combined spinal-epidural anesthesia: the effect of volume versus dose.
The reinforcement of anesthesia by an epidural "top-up" in combined spinal-epidural anesthesia may be explained by a dual mechanism: a volume effect compressing the dural sac and a local anesthetic effect. The purpose of our study was to investigate the relative importance of each of these factors. Fifty patients scheduled for lower limb orthopedic surgery under combined spinal-epidural anesthesia were randomly allocated to one of five groups comprising 10 patients each. Using a needle-through-needle technique, all patients received a subarachnoid injection of 10 mg of plain bupivacaine and an epidural catheter. After the maximal level of sensory blockade as a result of the subarachnoid injection had been established, an epidural top-up was given according to the randomization code. Patients in Group 1 received 10 mL of bupivacaine 0.25%; patients in Group 2 received 10 mL of saline; patients in Group 3 received 5 mL of bupivacaine 0.5%; patients in Group 4 received 5 mL of saline; and patients in Group 5 received no epidural top-up. The maximal level of sensory blockade was then assessed for an additional 30 min. In Groups 1-4, the maximal level of sensory blockade increased significantly, whereas there was no significant increase in Group 5. There was no significant difference in the increase in the maximal level of sensory blockade among Groups 1-4. We conclude that, under the conditions of our study, there is no difference between 5 and 10 mL with regard to the volume effect of an epidural top-up in combined spinal-epidural anesthesia and that to produce an additional local anesthetic effect with bupivacaine, the dose must be larger than 25 mg. ⋯ In combined spinal-epidural anesthesia, an epidural "top-up" may increase the maximal level of sensory blockade by means of a volume effect and a local anesthetic effect. In this study, volumes of 5 and 10 mL produced a similar increase, and 25 mg of bupivacaine was insufficient to produce an additional local anesthetic effect.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Clinical TrialThe use of lidocaine for preventing the withdrawal associated with the injection of rocuronium in children and adolescents.
We designed this study to examine the incidence and degree of movement after the administration of rocuronium in children and adolescents and to measure the treatment effect of lidocaine for its prevention. One hundred patients (aged 5-18 yr) were randomly assigned to two groups. After general anesthesia was induced with 5 mg/kg thiopental sodium and manual occlusion of venous outflow was performed, one group of patients received 0.1 mL/kg 1% lidocaine i.v.. A second group received 0.1 mL/kg of isotonic sodium chloride solution as a placebo control. Venous outflow occlusion was held for 15 s, released, and immediately followed by the administration of rocuronium 1 mg/kg i.v.. The patient's response to rocuronium injection was graded using a 4-point scale. We observed that the incidence of withdrawal was 84% in the placebo group and was significantly decreased to 46% in patients pretreated with lidocaine (P < 0.001). This study demonstrates that the i.v. injection of rocuronium is commonly associated with a withdrawal reaction in anesthetized pediatric patients and that this reaction can be attenuated or eliminated by pretreatment with i.v. lidocaine. ⋯ Pain on injection of rocuronium in pediatric patients can be alleviated by pretreatment with i.v. lidocaine.