Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialAttenuation of pain in a randomized trial by suppression of peripheral nociceptive activity in the immediate postoperative period.
Peripheral neuronal barrage from tissue injury produces central nervous system changes that contribute to the maintenance of postoperative pain. The therapeutic approaches to blocking these central changes remain controversial, because previous studies have not differentiated presurgical interventions from those administered after tissue injury, yet before pain onset. In this study, we evaluated the relative contributions of blockade of nociceptive input during surgery or during the immediate postoperative period on pain suppression. Subjects were randomly allocated to one of four groups: preoperative 2% lidocaine, postoperative 0.5% bupivacaine, both, or placebo injections. General anesthesia was induced and third molars extracted. Pain was assessed over 4 h and at 24 and 48 h. The beta-endorphin in blood samples increased twofold during surgery, which is indicative of activation of the peripheral nociceptive barrage in response to painful stimuli. Pain was decreased in the immediate postoperative period in the bupivacaine groups, whereas it increased in the lidocaine group over time. Pain intensity was less 48 h after surgery in the groups whose postoperative pain was blocked by the administration of bupivacaine, but no effect was demonstrated for the preoperative administration of lidocaine alone. These results in the oral surgery pain model suggest that minimizing the peripheral nociceptive barrage during the immediate postoperative period decreases pain at later time periods. In contrast, blocking the intraoperative nociceptive barrage does not appear to contribute significantly to the subsequent reduction in pain. ⋯ Suppression of postoperative pain immediately after surgery attenuates the pain experienced 1 to 2 days after surgery. These findings suggest that pain after minor surgery can be prevented by blocking the development of pain processes that amplify pain for days after surgery.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Clinical TrialHalothane, isoflurane, and fentanyl increase the minimally effective defibrillation threshold of an implantable cardioverter defibrillator: first report in humans.
Placing an implantable cardioverter defibrillator (ICD) involves the induction of ventricular fibrillation, whereupon the minimally effective defibrillation energy threshold (DFT) is determined. We evaluated the effects of 0.7% halothane, 1% isoflurane, or 1.5 micro g/kg of IV fentanyl during N(2)O/oxygen-based general anesthesia (GA) or those of subcutaneous 1.5% lidocaine plus IV 0.35 mg/kg of propofol on the DFT during ICD implantation in humans (n = 20 per group). Thirty minutes after the first set of DFT measurements under such conditions, the inhaled anesthetics were withdrawn, and all three GA groups received fentanyl 1 microg/kg IV (second set). A third set was taken 30 min later, before the GA patients awakened and when only N(2)O/oxygen was delivered for GA. The lidocaine plus propofol patients were given the same IV propofol bolus 1 min before each fibrillation/defibrillation trial and at the same time points as the three GA groups. The first DFTs were 16.1 +/- 2.2 J (halothane), 17.7 +/- 2.7 J (isoflurane), 16.4 +/- 2.9 J (fentanyl), and 12.9 +/- 3.8 J (lidocaine plus propofol) (P = 0.01). The second set of DFTs were significantly lower than the first sets for the halothane (P = 0.01) and isoflurane (P = 0.02), but not the fentanyl or lidocaine plus propofol, regimens. The third DFTs were significantly (P < 0.01) lower than the first ones for the three GA groups, but not for the lidocaine plus propofol patients. Thus, halothane, isoflurane, and fentanyl increased DFT values during ICD implantation in humans, whereas lidocaine plus intermittent small-dose IV propofol minimized these thresholds. ⋯ Halothane, isoflurane, and IV fentanyl added to N(2)O/oxygen-based general anesthesia similarly increase minimal defibrillation threshold energy requirements (DFT) during cardioverter defibrillator implantation in humans. Subcutaneous lidocaine plus intermittent small-dose IV propofol minimizes DFT compared with these general anesthetics while providing equal patient satisfaction.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialSmall-dose intrathecal lidocaine versus ropivacaine for anorectal surgery in an ambulatory setting.
Spinal anesthesia with the local anesthetic lidocaine has come under scrutiny because it is associated with transient neurologic symptoms (TNS). We designed this study to prospectively compare the efficacy of ropivacaine as an alternative to lidocaine in patients undergoing elective outpatient anorectal procedures. Seventy-two patients were randomized to receive either hyperbaric lidocaine 25 mg with fentanyl 20 microg (n = 37) or hyperbaric ropivacaine 4 mg with fentanyl 20 microg (n = 35). Patients were examined for motor block, sensory block, and block duration. Patients were contacted at 24, 48, 72, and 168 h and questioned about their perceptions of pain after the spinal with specific questions designed to diagnose TNS. There were no patients with TNS in either group. There was no significant difference between the lidocaine and ropivacaine groups in any of the outcomes studied. In conclusion, intrathecal hyperbaric small-dose ropivacaine with fentanyl is an acceptable anesthetic for anorectal surgery. ⋯ In this prospective trial, small-dose ropivacaine with fentanyl was as effective as small-dose lidocaine with fentanyl for anorectal procedures in the ambulatory setting.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Clinical TrialPrevention of nausea and vomiting with tandospirone in adults after tympanoplasty.
We have hypothesized that the 5-hydroxytrypta-mine-1A receptor agonist tandospirone reduces postoperative nausea and vomiting (PONV). In a double-blinded, randomized design, 3 groups of 30 patients each received 1 of the following oral medications 90 min before arrival in the operating room, together with famotidine 20 mg: 1) placebo (P group), 2) tandospirone 10 mg (T10 group), or 3) tandospirone 30 mg (T30 group). Standard anesthetic regimens and techniques were applied for all patients. All episodes of PONV were recorded during the following time intervals: 0-3 h and 3-24 h after the end of general anesthesia. The incidence of a complete response, defined as no PONV and no need for other rescue antiemetics, was significantly more frequent in the T30 group than in the P group during 0-24 h (P = 0.019), especially during 3-24 h (P = 0.007) after general anesthesia. In conclusion, premedication with oral tandospirone is effective against PONV in patients undergoing tympanoplasty under general anesthesia. ⋯ Oral tandospirone reduced the incidence of postoperative nausea and vomiting without significant adverse effects in adults undergoing tympanoplasty under general anesthesia.
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Anesthesia and analgesia · Nov 2002
Randomized Controlled Trial Comparative Study Clinical TrialSevoflurane provides faster recovery and postoperative neurological assessment than isoflurane in long-duration neurosurgical cases.
Sevoflurane (SEVO) provides faster emergence than isoflurane (ISO). This advantage is thought to magnify with increased duration of exposure. In addition, SEVO has several of the characteristics of an ideal neuroanesthetic. We designed a prospective, randomized, double-blinded study to compare the recovery profile of SEVO versus ISO in neurosurgery. Sixty patients undergoing intracranial surgery were enrolled. They were randomized to receive SEVO or ISO in 40% oxygen as part of a balanced anesthetic regimen. The anesthetic concentration (0.5 to 1.0 minimum alveolar anesthetic concentration [MAC]) was adjusted to maintain mean arterial blood pressure within 20% of the preinduction baseline. At the end of the surgery, neuromuscular blockade was reversed, anesthetics were discontinued without prior tapering, and fresh gas flow was increased to 10 L/min. Recovery end-points were measured as the time from closure of the anesthetic vaporizer. Mean MAC-hours were identical in both groups (4.7). Patients in the SEVO group demonstrated a shorter time to emergence (P = 0.02) and for response to command (squeeze hand, P = 0.03; move feet, P = 0.01). Patients in the SEVO group obtained a Glasgow coma scale score of >/=10 5 min before patients in the ISO group (P = 0.04). Obtaining an early neurological examination can be critical in neurosurgical patients. The observed difference in emergence between SEVO and ISO could therefore be of clinical importance. ⋯ The low-solubility anesthetic, sevoflurane, provides faster recovery and postoperative neurological assessment than isoflurane after long-duration (4.7 MAC-h) intracranial surgery.