Regional anesthesia
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Regional anesthesia · May 1989
Precordial Doppler monitoring and pulse oximetry during cesarean delivery: detection of venous air embolism.
Venous air embolism (VAE) is a potential but rare complication of cesarean delivery that can be associated with morbidity and death. Uterine sinuses are susceptible to the entrance of air during cesarean delivery. To define the incidence of VAE and its relation to arterial oxygen saturation (SaO2) and consequent electrocardiographic (ECG) changes, a prospective study was undertaken in which precordial Doppler monitoring was conducted during cesarean delivery. ⋯ Although all ECG changes resolved spontaneously without sequelae, the potential clearly existed for life threatening embolic events. Thus, precordial Doppler monitoring of cesarean delivery patients demonstrated a surprisingly high incidence of Doppler changes consistent with VAE. Some episodes were associated with a significant reduction in SaO2 and rarely with ECG changes.
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Regional anesthesia · May 1989
Comparative StudyAntinociceptive effects of localized administration of opioids compared with lidocaine.
To study possible antinociceptive effects of perineurally administered opioids, the rat infraorbital nerve block (IONB) model was employed for investigations of opioids (morphine, meperidine, buprenorphine, ethylketocyclazocine, and fentanyl) of differing receptor selectivity and physicochemical properties such as lipid solubility. Only meperidine in doses greater than 1 mg/kg produced localized analgesia, the duration of which increased dose-dependently. Naloxone failed to counteract the analgesic effects of meperidine. ⋯ The two agents caused a similar duration of sensory block in infiltration anesthesia. Meperidine was shorter than lidocaine in epidural anesthesia. The characteristics of blocks induced by the two agents may be explained by structural differences and associated differences in physicochemical properties such as lipid solubility and pKa.
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Regional anesthesia · May 1989
Randomized Controlled Trial Comparative Study Clinical TrialEpidural morphine or butorphanol augments bupivacaine analgesia during labor.
To determine the efficacy and the safety of epidural morphine or butorphanol combined with bupivacaine, 40 healthy parturients were studied during labor and delivery. All patients received an epidural test dose of 2 ml of 0.5% bupivacaine. Patients were then randomly assigned to receive one of four epidural regimens in a double-blind fashion: 0.25% bupivacaine + 1 mg butorphanol (Group I), 0.25% bupivacaine + 2 mg butorphanol (Group II), 0.25% bupivacaine + 2 mg morphine (Group III), or 0.25% bupivacaine alone (Group IV). ⋯ All neonates were vigorous at 5 minutes and had good Apgar Scores, umbilical cord acid base status, and Neurological Adaptive Capacity Scores. The authors conclude that adding small doses of either morphine or butorphanol to epidural bupivacaine during labor is effective and safe. Butorphanol may be preferable since none of the patients experienced pruritus.
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Regional anesthesia · May 1989
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of pH adjustment of 2% mepivacaine on epidural anesthesia.
Two-hundred men, scheduled for elective meniscectomy under epidural anesthesia, were randomly assigned to receive either a standard 2% mepivacaine solution (n = 100) or a pH adjusted 2% mepivacaine solution (pHAS, n = 100). The pHAS was freshly prepared before the block by adding 0.1 mEq of NaHCO3 per ml of mepivacaine solution. After a test-dose, the anesthetic solution was injected to produce a level of sensory anesthesia to T10. ⋯ Patients in the pHAS group showed a significant shortening of onset time in T10 and in S2 segment (p less than .001). Grade 3 motor blockade was achieved in the same number of patients, but a faster motor block was observed in the pHAS group (p less than .05). Regression of both sensory and motor blockade in the two groups was not significantly different.