thiopental and Myocardial-Ischemia

To evaluate the effect of propofol infusion for both induction and maintenance of anesthesia on hemodynamics and recovery in elderly patients compared with conventional thiopental-isoflurane anesthesia.. Randomized, prospective, study.. Teaching hospital.. 60 nonpremedicated ASA physical status I, II, and III adult elderly patients scheduled to undergo total hip replacement surgery.. Patients received either intravenous propofol infusion at 0.75 mg/kg/min or thiopental bolus 2 to 4 mg/kg for induction, followed by variable-rate propofol infusion up to 0.15 mg/kg/min or isoflurane 0.5% to 1.5% for maintenance of anesthesia. Nitrous oxide and fentanyl supplements were given in all patients.. Perioperative hemodynamic changes, patient recovery profile, and myocardial ischemia incidents were assessed in both anesthetic groups. Induction of anesthesia by propofol infusion (1.6 mg/kg) did not produce significant hypotension (-8.3% +/- 5.5%) or bradycardia; these changes were similar to induction by thiopental bolus injection (3.3 mg/kg). Furthermore, increases in blood pressure and heart rate (HR) during endotracheal intubation were limited to 6% following propofol induction compared with 22% for thiopental induction. During maintenance of anesthesia, the decrease in MAP and HR was comparable in both anesthetic groups. Postanesthetic recovery times for patient to achieve wakefulness, mental orientation, and a maximum Aldrete score (10) were significantly faster in the propofol group, by 4 minutes, 6 minutes, and 20 minutes, respectively; however, the time to discharge from the postanesthesia care unit was not different. Holter-monitored perioperative myocardial ischemic events detected in 23% of the patients occurred independent of hemodynamic changes or the type of anesthetic administered.. Induction of anesthesia by propofol infusion in elderly patients produces greater attenuation of cardiovascular sympathetic response than thiopental bolus induction. Induction and maintenance of anesthesia by propofol infusion results in more rapid recovery in our elderly patients than thiopental isoflurane anesthesia.

Topics: Aged; Anesthesia Recovery Period; Anesthesia, Intravenous; Anesthetics, Inhalation; Anesthetics, Intravenous; Blood Pressure; Electrocardiography; Female; Hemodynamics; Hip Prosthesis; Humans; Intraoperative Complications; Isoflurane; Male; Myocardial Ischemia; Propofol; Thiopental

Halothane offers protection against the reperfusion injury of the myocardium. This study compared sevoflurane with halothane in its potential to modulate the effects of acute severe ischemia and reperfusion on the myocardium.. Experiments were conducted on 25 pigs. Anesthesia consisted of thiopental, vecuronium and fentanyl. The lungs were mechanically ventilated with oxygen and nitrogen. Animals were randomly allocated to receive either I MAC halothane or sevoflurane. A control group received fentanyl and pentobarbital. Regional myocardial function was measured with sonomicrometers. The left anterior descending coronary artery was occluded for 15 min followed by 60 min reperfusion.. Neither halothane nor sevoflurane protected the heart against the effects of acute and severe regional myocardial ischemia. During reperfusion, 89% of the animals receiving sevoflurane suffered from ventricular fibrillation compared with 30% in the halothane group (P < 0.005). Five minutes into the reperfusion period the animals subjected to halothane anesthesia demonstrated an 88% recovery in regional myocardial systolic function while in the sevoflurane group the recovery was 40% of pre-ischemic control (P < 0.05).. Halothane is associated with less reperfusion arrhythmias and, in addition, recovery of regional myocardial function during reperfusion was more rapid in the presence of halothane than with sevoflurane.

Topics: Adjuvants, Anesthesia; Anesthetics, Inhalation; Anesthetics, Intravenous; Animals; Fentanyl; Halothane; Methyl Ethers; Myocardial Contraction; Myocardial Ischemia; Myocardial Reperfusion Injury; Neuromuscular Nondepolarizing Agents; Pentobarbital; Protective Agents; Random Allocation; Sevoflurane; Stroke Volume; Swine; Systole; Thiopental; Vecuronium Bromide; Ventricular Fibrillation; Ventricular Pressure

To consider the anaesthetic problems in a patient with lepromatous leprosy undergoing general anaesthesia.. A 52 yr old man with lepromatous leprosy for five years was booked for elective radical nephrectomy. He received 100 mg dapsone per day po. The patient was asymptomatic for cardiovascular disease but his electrocardiogram showed complete left bundle branch block, inferior wall ischaemia with echocardiogram findings of 58% ejection fraction and left ventricular diastolic dysfunction. Other preoperative investigations (haemogram, serum urea and creatinine, liver function tests and chest X-ray) were normal. After premedication with diazepam, meperidine and promethazine, the patient received glycopyrrolate and anaesthesia was induced with thiopentone. Atracurium was given to facilitate tracheal intubation. Anaesthesia was maintained with intermittent positive pressure ventilation using N2O in oxygen with halothane. Anaesthesia and surgery were uneventful except that the patient had a fixed heart rate that remained unchanged in response to administration of anticholinergic, laryngoscopy, intubation and extubation.. Patients with lepromatous leprosy may have cardiovascular dysautonomia even when they are asymptomatic for cardiovascular disease.

Topics: Adjuvants, Anesthesia; Anesthesia, General; Anesthetics, Inhalation; Anesthetics, Intravenous; Atracurium; Bundle-Branch Block; Cardiac Output, Low; Dapsone; Echocardiography; Elective Surgical Procedures; Electrocardiography; Glycopyrrolate; Halothane; Heart Rate; Humans; Intermittent Positive-Pressure Ventilation; Leprostatic Agents; Leprosy, Lepromatous; Male; Middle Aged; Myocardial Ischemia; Nephrectomy; Neuromuscular Nondepolarizing Agents; Nitrous Oxide; Preanesthetic Medication; Thiopental; Ventricular Dysfunction, Left

Myocardial infarction still represents a major cause of morbidity and mortality following surgical procedures. Continuous computerized on-line vector-ECG has previously been shown to be useful in the detection of myocardial ischaemia, in acute myocardial infarction and unstable angina pectoris and for ischaemia monitoring after PTCA procedures. This method was presently tested for the possible influence of anaesthesia and surgery during cholecystectomy under general anaesthesia (n = 9), and during inguinal hernia repairs using a spinal block (n = 5). The patients had no history, symptoms or signs of ischaemic heart disease. Analyses of vectorcardiographic changes were made in relation to predefined standardized anaesthetic and surgical procedures, all of which potentially could influence the vector-ECG. Three vectorcardiographic trendparameters were studied: QRS-vector difference, ST-vector magnitude and ST-change vector magnitude. The overall vectorcardiographic changes were minimal and smaller than vectorcardiographic changes previously reported during myocardial ischaemia and infarction. Since anaesthetic and surgical procedures per se had only minor effects on the vector ECG recordings, it is concluded that continuous computerized on-line vectorcardiography will not be skewed by these procedures. Hence, vectorcardiography has the potential of becoming a new monitor for the detection of perioperative myocardial ischaemia.

Topics: Adult; Aged; Anesthesia, Intravenous; Anesthesia, Spinal; Bupivacaine; Cholecystectomy; Female; Fentanyl; Hernia, Inguinal; Humans; Intraoperative Complications; Male; Microcomputers; Middle Aged; Monitoring, Intraoperative; Myocardial Ischemia; Online Systems; Posture; Thiopental; Vectorcardiography

This study was designed to investigate the changes in regional distensibility of the ischemic segment and of a remote nonischemic segment brought about by graded myocardial ischemia.. Ventricular distensibility is a major determinant of left ventricular end-diastolic pressure. The effects of graded myocardial ischemia on the regional distensibility of the ischemic area have not been studied. Moreover, there are few data on the effects of myocardial ischemia on the regional distensibility of the nonischemic myocardium.. Nine anesthetized open chest mongrel dogs were fitted with instruments to measure left ventricular pressure and circumferential length (sonomicrometry) in the ischemic segment and in a nonischemic segment. The pressure-length relation was modified by stepwise infusion and withdrawal of 200 ml of each dog's own blood over 30 min in five consecutive stages of regional ischemia. Unstressed dimensions were obtained by repeated inferior vena cava occlusions. In both segments, regional distensibility was assessed at end-diastole by means of the constants of the pressure-length (chamber stiffness), the pressure-strain and the force-strain (myocardial stiffness) relations.. In the ischemic segment, partial and complete coronary occlusions were associated with a twofold increase in the chamber stiffness constant, the pressure-strain constant and the myocardial stiffness constant, whereas in the nonischemic segment the chamber stiffness constant, the pressure-strain constant and the myocardial stiffness constant increased by 50%.. Regional myocardial ischemia is associated with a decrease in distensibility of both the ischemic and the remote nonischemic myocardium.

Topics: Analysis of Variance; Anesthesia; Animals; Diastole; Disease Models, Animal; Dogs; Female; Halothane; Hemodynamics; Male; Myocardial Contraction; Myocardial Ischemia; Systole; Thiopental