Regional anesthesia
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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 · Mar 1989
A two-person technique for epidural needle placement and medication infusion.
Traditional techniques of epidural needle placement have not proved satisfactory in patients who have had a previous laminectomy and may have epiduroarachnoiditis. A two-person technique was developed to: 1) simplify performance of difficult, epidural needle placement; 2) allow both resident and staff a simultaneous "hands-on" teaching experience; 3) allow a painless method of medication administration in patients with altered epidural anatomy; and 4) allow a simple method for determination of epidural space pressures. A glass syringe and extension tubing filled with saline are connected to the epidural needle. ⋯ The column of saline falls and fluctuates with heart beat, providing verification of correct needle placement. Medication is placed in the barrel of the syringe and allowed to infuse by gravity. The two-person technique has achieved both patient and resident acceptance, and allows a painless method of medication administration in patients with altered epidural space anatomy.
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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.