Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2000
Clinical TrialThe safety and efficacy of parent-/nurse-controlled analgesia in patients less than six years of age.
Over the past 5 yr, we have treated nonsurgical and postoperative pain in children <6 yr of age by using a patient-controlled analgesia pump to deliver small-dose continuous IV opioid infusions supplemented by parent- and nurse-controlled opioid bolus dosing. We call this technique parent-/nurse-controlled analgesia (PNCA). Because the safety and efficacy of PNCA have not been previously evaluated, we have undertaken a prospective, 1-yr observational study to determine patient demographics, effectiveness of analgesia, and the incidence of complications (pruritus, vomiting, and respiratory depression) in patients receiving PNCA. Data were collected on 212 children (98 female) who were treated on 240 occasions with PNCA for episodes of pain. Patients averaged 2.3 +/- 1.7 yr of age and 11 +/- 5 kg, and received a median of 4 (range 2-54) days of PNCA therapy. Maximum daily pain scores were < or =3/10 (objective pain scale) or < or =2/5 (objective or self-report pain scale) in more than 80% of all occasions of PNCA use. PNCA usage was associated with an 8% incidence of pruritus and a 15% incidence of vomiting on the first day of treatment. Nine children studied received naloxone, four (1.7%) for treatment of PNCA-related apnea or desaturation. All had improvement in their symptoms after naloxone administration. ⋯ Parent-/nurse-controlled analgesia provided effective pain relief in most children <6 yr of age experiencing nonsurgical or postoperative pain. The observed incidence of vomiting and pruritus was similar to that seen in older patients treated with patient-controlled analgesia. However, significant respiratory depression, although uncommon, did occur, thus reinforcing the need for close patient monitoring.
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Anesthesia and analgesia · Sep 2000
Clinical TrialA preliminary investigation of remifentanil as a labor analgesic.
In this preliminary investigation, we evaluated the safety and analgesic efficacy of IV remifentanil for labor pain. Four women were studied, and then the trial was terminated because administration of this novel synthetic opioid produced significant maternal side effects in the absence of effective pain control.
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Anesthesia and analgesia · Sep 2000
Case ReportsRecurring brachial plexus neuropathy in a diabetic patient after shoulder surgery and continuous interscalene block.
The performance of regional blockade on a patient with a preexisting neurologic condition or a history of neurologic complications after regional anesthesia is controversial. We present a case of recurring brachial plexus neuropathy in a diabetic patient after two shoulder procedures performed 4 mo apart. In both cases, the patient underwent intensive physical therapy with continuous postoperative interscalene analgesia.
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Anesthesia and analgesia · Sep 2000
Comparative StudyTolerability of large-dose intravenous levobupivacaine in sheep.
In preclinical pharmacological studies of levobupivacaine (S-bupivacaine), we determined its tolerability, cardiovascular actions, and pharmacokinetics, and we estimated its margin of safety compared with bupivacaine in conscious sheep. Levobupivacaine HCl. H(2)O was infused IV for 3 min into 10 previously instrumented ewes (approximately 50 kg). On subsequent days, the doses were increased by 50 mg from 200 or 250 mg until fatality occurred. All doses produced convulsions, QRS widening, and cardiac arrhythmias. With incremental doses, 4 of 4 animals survived 200 mg, 7 of 10 survived 250 mg, 3 of 7 survived 300 mg, but 0 of 3 survived 350 mg. Death resulted from sudden onset ventricular fibrillation (n = 3, within 2-3 min), electromechanical dissociation-pump failure (n = 5, within 4-5 min), or ventricular tachycardia-induced cardiac insufficiency (n = 2, >10 min). The estimated fatal dose (mean +/- SD) was 277 +/- 51 mg for levobupivacaine (compared with 156 +/- 31 mg found previously for bupivacaine). Pharmacokinetic analysis indicated initial and total distribution volumes = 4.5 (+/-1.6) and 97 (+/-22) L, total clearance = 1.7 (+/-0.4) L/min, and slow half life = 70 (+/-29) min; these values did not differ from those found previously with smaller doses. Heart and brain tissue levobupivacaine concentrations were approximately 3 times those in arterial blood. The doses of levobupivacaine survived were larger than found previously for bupivacaine, indicating its greater margin of safety. ⋯ Levobupivacaine produced fatal cardiac toxicity at doses significantly greater than those found in previous studies with bupivacaine. As the two drugs have similar potency for producing clinical nerve blocks, the data imply that levobupivacaine should provide a safer alternative to bupivacaine in practice.
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Anesthesia and analgesia · Sep 2000
The safety of one, or repeated, vital capacity maneuvers during general anesthesia.
A vital capacity maneuver (VCM) (inflating the lungs to 40 cm H(2)O for 15 s) is effective in relieving atelectasis during general anesthesia or after cardiopulmonary bypass (CPB). The study was undertaken to investigate the safety of one or repeated VCM. Five groups of six pigs were studied. Two groups had general anesthesia for 6 h and one group received a VCM every hour. Three other groups received CPB. VCM was performed after CPB in two of these groups. VCM was then repeated every hour in one of the groups. Lung damage was evaluated by extravascular lung water (EVLW) measurement, light microscopy, and the half-time (T(1/2)) of disappearance from the lung of a nebulized aerosol containing (99m)Tc-DTPA. No changes were noted in extravascular lung water. The pigs subjected to VCM decreased their T(1/2). In the groups exposed to repeated VCM, T(1/2) remained lowered (CPB pigs) or decreased over time (non-CPB pigs). No lung damage could be seen on the morphology study. These results suggest that one VCM is a safe procedure. The increase in lung clearance of (99m)Tc-DTPA not associated with an increase in lung water when VCM is repeated may have been caused by an increase in lung volume. Therefore, repeated VCM also appears to be safe. ⋯ This study demonstrates in an animal model that inflating the lung once or repeatedly to the vital capacity is a safe procedure. This maneuver, also called the vital capacity maneuver, can be used to relieve lung collapse which occurs in all patients during general anesthesia.