Anesthesia and analgesia
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Anesthesia and analgesia · May 2004
Ultrastructural findings in human spinal pia mater in relation to subarachnoid anesthesia.
We examined ultrastructural details such as the cellular component and membrane thickness of human spinal pia mater with the aim of determining whether fenestrations are present. We hypothesized that pia mater is not a continuous membrane but, instead, that there are fenestrations across the pial cellular membrane. The lumbar dural sac from 7 fresh human cadavers was removed, and samples from lumbar spinal pia mater were studied by special staining techniques, immunohistochemistry, and transmission and scanning electron microscopy. A pial layer made by flat overlapping cells and subpial tissue was identified. We found fenestrations in samples from human spinal pia mater at the thoracic-lumbar junction, conus medullaris, and nerve root levels, but these fenestrations did not appear at the thoracic level. We speculate whether the presence of fenestrations in human spinal pia mater at the level of the lumbar spinal cord and at the nerve root levels has any influence on the transfer of local anesthetics across this membrane. ⋯ The ultrastructural anatomy of the human pia mater, such as pial cells, membrane thickness, and subpial tissue at different levels of the thoracic and lumbar spinal cord and nerve roots, was studied by special staining techniques, immunohistochemistry, and transmission and scanning electron microscopy. Fenestrations were found in samples at the thoracic-lumbar junction, conus medullaris, and nerve root levels. No fenestrations were found in samples at the thoracic level. At present, we cannot determine the significance of these findings.
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Anesthesia and analgesia · May 2004
Randomized Controlled Trial Clinical TrialSedation with midazolam leads to reduced pain after dental surgery.
Our principal objective in this study was to evaluate the potential pain reducing effect of i.v. midazolam in patients undergoing oral surgery. One-hundred-twenty-five patients with impacted mandibular third molars requiring removal under local anesthetic were randomized into 2 groups. The first group (n = 64) was administered i.v. midazolam by titration until a clinical end-point of conscious sedation followed by local anesthetic before surgery; the second group (n = 61) was the control and was administered only local anesthetic before surgery. The surgery was performed in a standardized manner in both groups by the same surgeon. Outcome measures were four primary end-points: pain intensity as assessed by a 100-mm visual analogue scale and a 4-point categorized scale hourly for 8 h, time to first analgesic, total analgesic (ibuprofen) consumption over the first 48 h, and a 5-point categorical patient global assessment scale (0 = poor, 1 = fair, 2 = good, 3 = very good, and 4 = excellent). Throughout the 8-h investigation period, patients in the midazolam group reported significantly lower pain intensity scores than those in the control group (19.0 +/- 13.2 mm versus 28.1 +/- 12.8 mm, P < 0.05). The patients in the midazolam group also reported significantly longer time to first analgesic (165.5 +/- 56.5 min versus 202.2 +/- 79.0 min, P < 0.05), less analgesic consumption (1275 +/- 364 mg versus 1688 +/- 407 mg, P < 0.001) and better patient global assessment (3.34 +/- 0.8 versus 2.4 +/- 0.9, P < 0.001). We conclude that systemically administered midazolam is effective in reducing postoperative pain after third molar surgery. ⋯ In this observer blinded study, we found that i.v. midazolam treatment (0.09 mg/kg) has a pain-reducing effect after third molar surgery, thus improving postoperative pain management.
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Anesthesia and analgesia · May 2004
Randomized Controlled Trial Clinical TrialInteractive music therapy as a treatment for preoperative anxiety in children: a randomized controlled trial.
In this study, we examined whether interactive music therapy is an effective treatment for preinduction anxiety. Children undergoing outpatient surgery were randomized to 3 groups: interactive music therapy (n = 51), oral midazolam (n = 34), or control (n = 38). The primary outcome of the study was children's perioperative anxiety. We found that children who received midazolam were significantly less anxious during the induction of anesthesia than children in the music therapy and control groups (P = 0.015 and P = 0.005, respectively). We found no difference in anxiety during the induction of anesthesia between children in the music therapy group and children in the control group. An analysis controlling for therapist revealed a significant therapist effect; i.e., children treated by one of the therapists were significantly less anxious than children in the other therapist group and the control group on separation to the operating room (OR) (P < 0.05) and on entrance to the OR (P < 0.05), but not on the introduction of the anesthesia mask (P = not significant). Children in the midazolam group were the least anxious even after controlling for therapist effect (P < 0.05). We conclude that music therapy may be helpful on separation and entrance to the OR, depending on the therapist. However, music therapy does not appear to relieve anxiety during the induction of anesthesia. ⋯ Depending on the music therapist, interactive music therapy may relieve anxiety on separation and entrance to the operating room but appears less effective during the induction of anesthesia.
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Anesthesia and analgesia · May 2004
Randomized Controlled Trial Clinical TrialPostcesarean analgesia with spinal morphine, clonidine, or their combination.
In this randomized, double-blind trial in 240 women, we investigated the analgesic efficacy and duration of subarachnoid fentanyl 15 microg with morphine, clonidine, or both morphine and clonidine for cesarean delivery. A dose-finding analysis showed similar postoperative efficacy and side effects for groups receiving morphine 100 microg with clonidine 60, 90, or 150 microg. Data from these groups were combined (MC60-150, n = 113) and compared with groups receiving morphine 100 microg (n = 39), clonidine 150 microg (n = 39), or morphine 100 microg plus clonidine 30 microg (n = 41). The four groups differed in the time to patient-controlled morphine use and cumulative morphine consumption (P < 0.0001 and P < 0.001, respectively), with the longest duration and smallest dose in MC60-150. Pain scores were significantly different among groups. Onset of sensory block, ephedrine requirement and incidence of hypotension, patient satisfaction, and recovery were similar. Groups receiving clonidine had greater sedation, those receiving morphine had more severe pruritus, and group MC60-150 showed a trend to more vomiting intraoperatively. Compared with morphine 100 microg or clonidine 150 microg alone, the combination of subarachnoid morphine 100 microg and at least 60 microg of clonidine was found to increase the duration of postcesarean analgesia, reduce opioid requirement, and increase intraoperative sedation. ⋯ A multimodal approach to postcesarean analgesia, using subarachnoid bupivacaine, fentanyl, morphine 100 microg, and clonidine 60 microg, improves pain relief compared with morphine 100 microg or clonidine 150 microg alone, but increases intraoperative sedation and may increase perioperative vomiting.
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Anesthesia and analgesia · May 2004
Randomized Controlled Trial Clinical TrialMetoprolol and coronary artery bypass grafting surgery: does intraoperative metoprolol attenuate acute beta-adrenergic receptor desensitization during cardiac surgery?
Cardiac surgery results in significant impairment of beta-adrenergic receptor (beta AR) function and is a cause of depressed myocardial function after surgery. We previously demonstrated that acute administration of beta AR blocker during cardiopulmonary bypass (CPB) in an animal model of coronary artery bypass grafting (CABG) surgery attenuates beta AR desensitization, whereas chronic oral beta-blockade therapy in patients undergoing CABG surgery does not prevent it. Therefore we hypothesized that acute administration of metoprolol during CABG surgery would prevent acute myocardial beta AR desensitization. A placebo-controlled initial phase (n = 72) was performed whereby patients were randomized to either metoprolol 10 mg or placebo immediately before CPB. Then a second dose-finding study was performed where patients received 20 mg (n = 20) or 30 mg (n = 20) of metoprolol. Hemodynamic monitoring, atrial membrane adenylyl cyclase activity, atrial beta AR density, and postoperative outcomes were measured. All groups showed similar decreases in isoproterenol-stimulated adenylyl cyclase activity (13%-24%). Cardiac output remained similar in all 4 groups throughout the intraoperative and postoperative period. In addition, patients receiving metoprolol 20 or 30 mg had less supraventricular arrhythmias 24 h postoperatively compared with patients receiving metoprolol 10 mg or placebo. Therefore, unlike our previous animal model of CABG surgery, metoprolol did not attenuate myocardial beta AR desensitization. ⋯ We investigated whether IV metoprolol given during cardiac surgery attenuates myocardial beta-adrenergic receptor (beta AR) desensitization. Although metoprolol did not reduce beta AR desensitization, the incidence of supraventricular arrhythmias was reduced by 75% in patients receiving 20 mg or 30 mg metoprolol.