Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1990
Rate of change of somatosensory evoked potentials during isoflurane anesthesia in newborn piglets.
Most studies of the effects of inhalation anesthetics on somatosensory evoked potentials (SSEPs) have examined SSEP at single times after initiation of an anesthetic. This study describes SSEP changes as functions of time of exposure to isoflurane. Both transient and sustained SSEP changes were observed. ⋯ The long time constants ranged from 7 to 33 min. At 0.5% isoflurane, SSEP changes were often small or not sustained, and the changes could not always be well described by an exponential curve. These data suggest that the time-course of anesthetic effects on SSEPs may be prolonged and complex, and the possibility of changes over time should be considered both in experimental studies and during intra-operative monitoring.
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Anesthesia and analgesia · Feb 1990
Comparative StudySciatic nerve blocks in children: comparison of the posterior, anterior, and lateral approaches in 180 pediatric patients.
Three techniques for blocking the sciatic nerve, differing in approach (posterior in group P; lateral in group L; and anterior in group A), were prospectively evaluated in 180 children who were also given light general anesthesia for surgery below the knee. Four anesthetic solutions with epinephrine (1% lidocaine, 0.5% bupivacaine, and two mixtures of 0.5% bupivacaine with either 1% lidocaine or 1% etidocaine) were administered to 15 patients in each group. The sciatic nerve was located by electrical stimulation or, when muscle twitches were not elicited, using a loss-of-resistance technique. ⋯ Although the spread of the anesthetic was different in the three groups, the distribution of anesthesia in the lower extremity was similar, including not only dermatomes supplied by the sciatic nerve, but also those supplied by the posterior femoral cutaneous nerve. No neurological sequelae were observed. It is concluded that the posterior and lateral approaches are the most suitable in children for blocking the sciatic nerve proximally.
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Anesthesia and analgesia · Feb 1990
Colorimetric end-tidal carbon dioxide monitoring for tracheal intubation.
We evaluated a colorimetric end-tidal carbon dioxide (ETCO2) detector (FEF end-tidal carbon dioxide detector, Fenem, New York, N. Y.) during 62 intubations in anesthetized patients who were hemodynamically stable. The intubations were performed during a drill that simulates difficult tracheal intubation and therefore is associated with an increased risk of esophageal intubation. ⋯ Colorimetric ETCO2 monitoring confirmed tracheal intubation more rapidly than did chest auscultation (P less than 0.001) or capnography (P less than 0.05), and detected esophageal intubation more rapidly than did chest auscultation (P less than 0.05) and as rapidly as capnography did. Confirmation of tracheal intubation was achieved earlier than detection of esophageal intubation with all three monitors (P less than 0.05). We conclude that colorimetric ETCO2 monitoring is a safe, reliable, rapid, simple, and portable method for determining endotracheal tube position for patients who are hemodynamically stable and should be recommended where capnography is not available.
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Anesthesia and analgesia · Feb 1990
Intrathecal morphine dose-response data for pain relief after cholecystectomy.
We studied the effect of low-dose intrathecal morphine (0.00-0.20 mg) on pain relief and the incidence of side effects after cholecystectomy in 139 patients divided into eight groups according to intrathecal morphine dose: groups 1 (0.00 mg), 2 (0.04 mg), 3 (0.06 mg), 4 (0.08 mg), 5 (0.10 mg), 6 (0.12 mg), 7 (0.15 mg), and 8 (0.20 mg). Preservative-free morphine hydrochloride mixed in hyperbaric tetracaine solution was administered at the time of induction of spinal anesthesia just before surgery. Pain relief was significantly greater for the first 24 h in groups 3, 4, 5, 6, 7, and 8 than in group 1. ⋯ Vomiting occurred significantly more often in group 1 than in groups 2, 3, 4, and 5. Intraoperative cholangiography and the postoperative clinical course indicated no increase in tone of the sphincter of Oddi in any patient. We conclude that 0.06-0.12-mg intrathecal morphine is the best dose range for pain relief after cholecystectomy without respiratory depression and with the lowest incidence of vomiting or pruritus, or both.