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Biomedical subjects

L Amaranath

Publications and source records attributed to L Amaranath.

At least 19 recordsLinked to original sources
PubMed1994

Caudal epidural blocks for elderly patients with lumbar canal stenosis.

OBJECTIVE: To determine the efficacy of caudal epidural blocks (CEB) in relieving pain and the duration of pain relief with CEB in elderly patients suffering from degenerative lumbar canal stenosis (LCS). DESIGN: This study was a descriptive, prospective study with a 10-month follow-up. PARTICIPANTS AND SETTING: Thirty patients, 76 +/- 6.7 years of age, with leg discomfort with or without back pain and with LCS documented by magnetic resonance imaging (MRI) within 1 year of the study, were recruited from the outpatient clinic of the Cleveland Clinic Florida. None of the subjects had received CEB or surgery for their leg discomfort and none had relief of pain by analgesics alone. MEASUREMENTS AND INTERVENTIONS: Subjects received a total of three doses of 0.5% Xylocaine with 80 mg Depo-Medrol into the caudal epidural space through the sacral hiatus at weekly intervals. The Roland 5-point pain rating scale was utilized before and at 2-month intervals up to 10 months after the CEB was administered. MRI was used to identify the degree of LCS. RESULTS: The degree of LCS on admission was moderate in 66.7% (n = 20) of the patients, mild in 23.3% (n = 7), and severe in the remaining 10% (n = 3). Patients had LCS involving 2.4 +/- 0.49 lumbar vertebrae. The degree of LCS is directly correlated with the pain level before CEB. After CEB, the pain level changed from 3.43 +/- 0.82 to 1.5 +/- 0.86 (P < 0.0000), with a significant relief of pain up to 10 months (the end of observation). The duration of pain relief ranged from 4 to 10 months (P < 0.0001). CONCLUSION: CEB offers significant pain relief and appears to be a reasonable therapeutic option among elderly patients with LCS. This alternative seems particularly important among patients with poor response to drug therapy and who are either poor surgical risks or who have refused surgery.

Aged↗
PubMed1993

Vancomycin does not enhance hypotension under anesthesia.

The rapid administration of vancomycin is associated with flushing and hypotension, a consequence of histamine release. The manufacturer discourages administering vancomycin to anesthetized patients, stating that vancomycin aggravates the hypotensive effects of anesthetics. To test this, we randomly assigned 36 adults (ASA classes I through III) to one of two groups: preinduction (Preind, n = 19) and postinduction (Postind, n = 17). Both groups received two different infusions: vancomycin (1 g/250 mL normal saline) and saline (250 mL normal saline) over 30-60 min. The Preind group received vancomycin before anesthesia was induced and saline was administered immediately after anesthesia was induced; for the Postind group, this order was reversed. This was done in a double-blind fashion. The anesthetic induction was standardized by the intravenous administration of thiopental and vecuronium and anesthetic maintenance by inhalation of nitrous oxide and enflurane. End-tidal enflurane, heart rate (HR), and blood pressure (BP) were measured every 3 min. Independent (unpaired) t-test was used in data analysis. The groups did not differ significantly. We conclude that vancomycin infusion may be given under anesthesia without significant adverse hemodynamic consequences if administered over a 30-60 min period of time.

Adult↗
PubMed1989

Efficacy of intermittent epidural morphine following posterior spinal fusion in children and adolescents.

Postoperative pain is a distressing and disabling feature of scoliosis surgery. Epidural morphine has recently been advocated to reduce the frequency and severity of postoperative pain in adults. A retrospective study of 35 patients was conducted to determine whether epidural administration of morphine is useful in the management of postoperative pain in children and adolescents following posterior spinal fusion. The derived data included dose and frequency of narcotic administration on the day of surgery and during the subsequent three days. On the first postoperative day, the total morphine given averaged only 16.4 mg in patients receiving epidural morphine compared to 27 mg in those receiving only conventional parenteral morphine. Similar significant differences persisted through the second postoperative day. Intermittent epidural injection of small doses of morphine can give satisfactory and prolonged analgesia for early postoperative pain management.

Adolescent↗
PubMed1986

Epidural analgesia for total hip replacement in a patient with dilated cardiomyopathy.

A 69-year-old patient with severe impairment of left ventricular function secondary to dilated cardiomyopathy underwent a successful total hip replacement under epidural analgesia. Perioperative heart rate and mean arterial pressure were stable at an analgesic level up to the seventh thoracic dermatome, achieved with mepivacaine two per cent with epinephrine. Asymptomatic pulmonary hypertension, occurring during the insertion of the femoral prosthesis, subsided spontaneously over the next twelve hours. The circulatory effects of epidural analgesia and their significance in a patient with dilated cardiomyopathy are discussed.

Aged↗
PubMed1978

Trimethaphan camsylate (Arfonad) and human plasma cholinesterase.

These results for the first time document that the brief duration of action of the ganglionic blocker, Arfonad (trimethaphan camsylate), is not due to inactivation by plasma cholinesterase. Inhibition of the enzyme in vitro by Arfonad was not altered by prior incubation of the drug in plasma at 37 degrees C for up to 16 hours nor by treatment with NaOH at 100 degrees C for 10 minutes. Both procedures inactivated succinylcholine. These results in vitro were confirmed in vivo by finding that the toxicity of Arfonad in mice was not significantly altered by these procedures whereas they rendered succinylcholine inocuous. Arfonad is a noncompetitive whereas succinylcholine is a competitive inhibitor of plasma cholinesterase using benzoylcholine as the substrate. The camphorsulfonate moiety of Arfonad was inactive in vitro but caused mild tremors in mice at relatively high doses.

Binding, Competitive↗
PubMed1977

Ethanol effects on active and passive Na+ flux in toad bladder.

Ethanol, like other anesthetics, has been reported to interfere with active Na+ transport in living membranes. In an attempt to elucidate the mechanism by which ethanol exerts this action, we tested in the toad bladder membrane: 1) the effect of ethanol on active Na+ transport, 2) the interaction of ethanol with vasopressin on Na+ transport, and 3) the effect of ethanol on passive Na+ flux. We found that, a) 1-500 microgram/ml of ethanol stimulated, and 10,000 microgram/ml depressed active Na+ transport; b) the combined effect of stimulating concentrations of ethanol and vasopressin, although suggestive of a positive interaction, might have arisen by chance (p = 0.08); c) depressant concentrations of ethanol failed to suppress the stimulation by vasopressin; and d) passive Na+ flux in bladders treated with ouabain and ethacrynic acid was not affected by ethanol (1-100 microgram/ml). These results indicate that ethanol in concentrations ranging from 1 to 10,000 microgram/ml does not block ATP/ATPase Na+ pump but apparently exerts a dose-dependent, stimulant-depressant effect on Na+ channels in the membrane.

Animals↗
PubMedDate not supplied

Relation of anesthesia to total hip replacement and control of operative blood loss.

Blood loss during total hip replacement has been reported as ranging from 500 to more than 4000 ml. To find reasons for this large variation, 167 case reports were studied. Blood loss was higher with nitrous oxide-oxygen-curare-morphine aneasthesia than with halothane-nitrous oxide-oxygen. Blood loss was also higher in patients with cups, prostheses, and neoplasms of the femoral head and neck than in patients with degenerative and rheumatoid arthritis. In patients undergoing bilateral total hip replacement, operative blood loss was significantly (p=0.05) higher during the second operation. However, the most striking correlation of blood loss was with intraoperative systolic blood pressure (r=0.84), a finding confirmed by a prospective study in 58 patients. Blood loss, operative time, the number of blood transfusions, and the hypotensive and hypoxic response to acrylic bone-cement application decreased when intraoperative systolic blood pressure was lowered by 20 to 30 percent of the preoperative value by the use of trimethaphan or sodium nitroprusside. This moderate reduction of blood pressure resulted in a saving of 2 to 3 units of blood in an average case and a considerably clearer surgical field. The authors consider moderate lowering of blood pressure to be a useful adjuvant in anesthesia for total hip replacement.

Adjuvants, Anesthesia↗
PubMedDate not supplied

The effect of general anesthetic agents, ouabain, and aldosterone on striated muscle contraction in toad.

Na+ and K+ transport, resting potentials, action potentials, and muscle contraction are interrelated in the excitation-contraction coupling process. Since anesthetics affect the electrogenic Na+ transport mechanism in the toad bladder model and the coupled Na+, K+ transport in muscle, the authors tested the hypothesis that the effects of inhalation anesthetics on ion transport and muscle contraction are parallel. In this study, the effects were assessed of 4 inhalation anesthetics and, for comparison, the effects of ouabain and aldosterone, on contractions of toad sartorius muscle. Cyclopropane, N2O, ether, and halothane, as well as ouabain and aldosterone, increased twitch height in low concentrations. Halothane, ether, and ouabain decreased twitch height in high concentrations. The effect of cyclopropane and N2O, oubain, and aldosterone on muscle contraction closely paralleled their action on electrogenic Na+ transport. This observation supports the hypothesis that the influence of these agents on muscle contraction is linked to the effect on active ion transport or that both effects are equally sensitive to anesthetic agents.

Aldosterone↗