Regional anesthesia
-
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.
-
Regional anesthesia · Mar 1989
Comparative StudyA comparison of cardiovascular responses of normotensive and hypertensive elderly patients following bupivacaine spinal anesthesia.
The hypotensive effects of spinal anesthesia were investigated in 60 patients aged 75 years or older and divided into two groups: 30 normotensive patients (group 1) and 30 treated hypertensive patients (group 2). In both groups, spinal anesthesia was performed in lateral decubitus position with 3 ml 0.5% isobaric bupivacaine. Hemodynamic measurements were performed before the establishment of spinal blockade and repeated during the 60 minutes following intrathecal injection. ⋯ Five patients in group 2 (but none in group 1) had a SBP decrease of 40% from baseline or more. The decreases in MBP and DBP were persistent after 60 minutes. These results suggest that pre-existing hypertension can be recognized as an important factor to explain blood pressures changes during isobaric bupivacaine spinal anesthesia in elderly patients.
-
Four local or regional anesthesia techniques for the insertion of cardiac pacemaker were studied prospectively in 40 patients. The four techniques studied were: local anesthesia, field block of the supraclavicular nerves, interscalene block at C4, and interscalene block at C6. The three goals of the study were to find the technique that gave the best quality of analgesia, the incidence of complications related to each technique, and the area of sensory innervation of C4. ⋯ Interscalene blocks at C4 and C6 were associated with complications and side effects more often than the two other techniques. The authors also suggest that the dermatome of C4 is not under the clavicle but above the clavicle. It was concluded that local anesthesia infiltration at the site of cardiac pacemaker insertion or field block of the supraclavicular nerves are the best techniques for cardiac pacemaker insertion.