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Biomedical subjects

M G Pratila

Publications and source records attributed to M G Pratila.

18 recordsLinked to original sources
PubMed1982

Enflurane depression of myocardial slow action potentials.

Effects of enflurane on myocardial electrophysiologic and contractile properties were examined by simultaneous measurement of action potentials (APs) and contractions in guinea-pig papillary muscle. Enflurane was administered in 1 to 6% concentrations in 5% CO2-95% O2 bubbled through the standard Tyrode's perfusing solution. After studying normal APs, slow APs were induced with 5 to 30 x 10(-8) M isoproterenol and/or 1 to 2 mM theophylline in partially depolarized muscles (typically -40 mV in 26 mM K+ media). AP characteristics and contractions measured during each enflurane application were analyzed. The maximum rate of rise (+Vmax) and amplitude of the normal AP was not depressed, although duration decreased in greater than or equal to 3% enflurane. In contrast, slow AP + Vmax declined significantly (P less than .05) to 90, 80 and 74% of control in enflurane concentrations of 2, 3 and 4%, respectively. Decrease in slow AP duration was significant only in 5 to 6% enflurane. In 1% enflurane, contractions declined to steady-state levels of 75 (fast AP) and 79% (slow AP) of control and fell to 20 (fast AP) and 35% (slow AP) in 4% enflurane. Enflurane concentrations of 2% and greater inhibit slow (Na+-Ca++) channels which mediate slow APs. This effect may be in part responsible for the negative inotropic effect of enflurane.

Action Potentials↗
PubMed1980

Sympathetic nervous system tonicity and post-coronary artery bypass hypertension.

To elucidate the pathogenesis of hypertension following coronary bypass surgery, blood pressure and plasma catecholamine concentration were measured in 28 patients with coronary artery disease who were undergoing myocardial revascularization procedures. Measurements were obtained on arrival in the operating room and 1 and 4 h after surgery. One hour after surgery, plasma norepinephrine (NE) increased significantly by 495 +/- 108 pg/ml (P less than 0.001) in the coronary artery disease group which developed hypertension, but the increase was not significant in the coronary artery patients who remained normotensive after surgery. However, 4 h after surgery, plasma NE increased significantly and to the same extent in both coronary artery disease groups, regardless of the change in blood pressure. Plasma epinephrine (E) also increased significantly 1 and 4 h after surgery in both groups. The observed change in plasma catecholamine concentration is direct evidence that the stress of surgery is a potent adrenergic stimulus, but the hemodynamic significance of the plasma catecholamine change remains unclear.

Blood Pressure↗
PubMed1979

Anaesthetic management of phaeochromocytoma.

The incidence, mortality, physiology, clinical findings and diagnosis of phaeochromocytoma are reviewed. Treatment, after adequate medical stabilization, must be surgical because of the high incidence of malignancy. Alpha-adrenergic receptor blockade and beta-adrenergic receptor blockade in the preoperative period was discussed. Anaesthetic management of patients with phaeochromocytoma requires close monitoring. Virtually all inhalational anaesthetic agents have been used in cases of phaeochromocytoma. Recent reports have favored enflurane. The merits of neuroleptanaesthesia and the various muscle relaxants are also discussed. Most authors favour lidocaine over propranolol for management of dysrhythmias during operation. Phentolamine or sodium nitroprusside are used for hypertension during operation. Hypotension is treated by fluid replacement with nor-epinephrine if a vasopressor becomes necessary. Close monitoring is necessary in the postoperative period. Adequate urinary output is of more importance than actual blood pressure levels.

Adrenal Gland Neoplasms↗
PubMed1979

Anaesthetic considerations in the prolonged Q-T interval (LQTS): a case report.

A case of prolonged Q-T interval syndrome (LQTS) with ventricular dysrhythmias is presented. The patient was unresponsive to medical treatment. Left stellate ganglion block, followed by surgical excision of the ganglion, resulted in reversion to normal sinus rhythm. The causes of LQTS, its treatment and the effects of anaesthetic agents are discussed.

Adult↗
PubMed1978

The effect of halothane anaesthesia on liver regeneration.

The effects of halothane and diethyl ether on the regenerating liver following 70 per cent hepatectomy were studied in Fisher/344 (F) rats. Our aim was to discover whether halothane administered repeatedly and over prolonged periods could influence the liver regenerative process or hepatocyte function. We also wished to know if the effects of halothane differed from those of diethyl ether. We found: 1. Prolonged halothane or diethyl ether anaesthesia did not inhibit liver mitotic activity, even if administered repeatedly. 2. The effects of halothane and diethyl ether on liver cell division were identical. 3. With reference to liver regeneration, halothane is as safe as diethyl ether when administered during extensive hepatectomy.

Animals↗
PubMedDate not supplied

A case of tachydysrhythmia. Refractory to propranolol and responsive to neostigmine.

A case of atrial fibrillation, with a fast ventricular response, which developed under enflurane anaesthesia is described in a patient previously treated with digitalis and propranolol. The intravenous administration of propranolol was ineffective whereas that of neostigmine and atropine, 2 hours later, was successful and reduced the ventricular rate to normal values.

Anesthesia, General↗
PubMedDate not supplied

The hepatoprotective effect of oxygen during halothane anesthesia.

The effects of halothane anesthesia on liver function, as reflected by postanesthetic changes in serum glutamic pyruvic transaminase (SGPT) levels, were evaluated in 2 groups of 40 patients. All patients had 2 halothane anesthetics. In 1 group, both anesthetics were administered at 1 atmosphere pressure with 30% O2 in the inspired air. In the 2nd group, both anesthetics were administered at 2 to 3 atmospheres (absolute) of pressure with 97 to 98% O2 in the inspired air. While the SGPT levels remained within the normal range in all cases, there was a significant rise in SGPT levels in patients undergoing surgery under 1 atmospheric pressure. Patients undergoing surgery at 2 to 3 atmospheres pressure (absolute) had SGPT levels which remained at low normal values. The difference in response of SGPT in the 2 groups was statistically significant. We conclude that increased O2 tensions alter the normal response of SGPT to halothane anesthesia and that increased O2 tensions appear to protect the liver from possible adverse responses to halothane or its metabolites.

Adult↗