Anesthesiology
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Despite evidence from animal experiments to the contrary, nitrous oxide (N2O) reportedly does not induce myocardial ischemia when used as an adjunct to fentanyl anesthesia in patients with coronary artery disease who have well-preserved left ventricular (LV) function. However, the incidence of ischemia with N2O administration in similar patients with poor LV function may be different. The effects of N2O on segmental LV function, as determined by two-dimensional transesophageal echocardiography, changes in the ST-segment of the electrocardiogram were compared with the effects of an equal concentration of nitrogen (N2) (crossover design) in 70 patients who required elective coronary artery bypass grafting. ⋯ Preoperative calcium channel blockers made no such differences. Onset of ischemia was not closely associated with hemodynamic changes. Thus, N2O does not induce clinically detectable myocardial ischemia in patients who have coronary artery disease, and poor LV function in situations in which the effects of deepening anesthetic depth and mild depression of global myocardial function are deemed desirable or harmless.
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Randomized Controlled Trial Comparative Study Clinical Trial
An evaluation of morphine and oxymorphone administered via patient-controlled analgesia (PCA) or PCA plus basal infusion in postcesarean-delivery patients.
The analgesic efficacy and adverse effects of morphine and oxymorphone in 32 patients who received traditional patient-controlled analgesia (PCA) following cesarean delivery were compared with those in 32 other patients receiving the same agents via PCA plus basal opioid infusion (PCA + BI). All patients were operated upon during epidural anesthesia with 2% lidocaine and 1:200,000 epinephrine to achieve a T4 sensory level. Upon first complaint of pain in the recovery room, patients were given a titrated iv loading dose of the assigned opioid until comfortable and were then provided with a programmable PCA device. ⋯ The level of sedation and incidence of nausea/vomiting and pruritus were also recorded. Patients utilizing PCA + BI noted significant reductions in resting pain scores with oxymorphone and decreased pain during movement with both opioids when compared with individuals using PCA alone (P less than 0.05). There were no significant differences between treatment groups in 24-h dose requirements or patient satisfaction with therapy (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)
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To evaluate the impact of anesthetics on the evolution of a cerebral injury, 33 rabbits were subjected to a cryogenic brain lesion, followed by 10 h of anesthesia with 1 MAC halothane or isoflurane (n = 11 each) or with an equipotent dose of pentobarbital (n = 11). The lungs were ventilated to a PaCO2 = 30-35 mmHg with O2/air and normothermia was maintained. Intracranial pressure (ICP), mean arterial pressure (MAP), central venous pressure (CVP), arterial blood gases, and pH, osmolality, and other blood chemistries were recorded. ⋯ ICP increased in all animals, but with no significant intergroup differences (ICP in halothane animals was numerically lower). There were no clear differences in the incidence of ventricular drainage (1 halothane, 5 isoflurane, 3 pentobarbital; P = 0.16). In spite of CSF drainage and angiotensin, CPP