The use of nitrates in cardiac anaesthesia.
Explore the source record for details and available documents.
Anesthesia↗
Biomedical subjects
G Ohqvist
Publications and source records attributed to G Ohqvist.
A comparison between morphine, meperidine and ketobemidone in continuous intravenous infusion for postoperative relief.
Morphine, meperidine and ketobemidone used in continuous i.v. infusion for postoperative pain relief were compared in a double-blind, controlled, prospective study in 81 consecutive consenting adult patients after open-heart surgery, with permission from the hospital ethics committee. During the first postoperative period, the infusion rates were fixed. Later on, when the infusion rate could be regulated according to individual patient needs, the variation in infusion rate was large, in accordance with earlier studies. No significant differences were demonstrated between the three analgesics with respect to efficacy of analgesia or side effects like shivering, nausea or vomiting. Respiratory depression following extubation was not observed. During shivering, there was a significant increase in the arterio-mixed venous difference of oxygen in all groups. The amounts of opioids used were relatively small compared to amounts used in patients following abdominal surgery. When interviewed some days after surgery, 18/74 patients remembered moderate pain and 11 severe pain during the stay in the ICU.
Double-Blind Method↗
A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal intubation.
Thirty-five non-selected, consenting patients were studied during induction of anesthesia before coronary artery bypass grafting. Anesthesia was induced with diazepam, thiopentone and fentanyl, followed by pancuronium. Before induction, 200 MBq Tc 99 m - HSA was given i.v. and ejection fraction (EF) of the left ventricle was measured with a collimated single-crystal probe. The patients were allocated to five groups (seven patients in each) treated with: Group A: nitroglycerin i.v. bolus 4 micrograms x kg-1 given 30-60 s before laryngoscopy; Group B: nitroglycerin i.v. in continuous infusion, 1 micrograms x kg-1 x min-1 started before induction; Group C: two-stage topical anesthesia of the vallecula region and larynx with lidocain; Group D: a combination of nitroglycerin and topical anesthesia (as in Group B and C); and Group E: propranolol i.v. 0.01 mg x kg-1 given 5 min before intubation. All groups reacted in the same way during induction of anesthesia up to the point of laryngoscopy. End-diastolic volume and systemic arterial pressure decreased while cardiac index remained unchanged and EF increased. During laryngoscopy and intubation, however, differences between the groups were evident. Nitroglycerin i.v. as a bolus effectively prevented a reduction in EF and an increase in left ventricular volume. In addition to these beneficial hemodynamic effects, there was a moderate increase in heart rate and a reduction of stroke index. Continuous infusion of nitroglycerin and propranolol i.v. had no effect, since EF fell and left ventricular volume increased. Patients receiving topical anesthesia demonstrated a blunted response to endotracheal intubation with a moderate decrease in EF and an unchanged (Group C) or slightly increased (Group D) left ventricular volume.
Adult↗
Veno-venous extracorporeal membrane oxygenation with a heparin-coated system in adult respiratory distress syndrome.
Three patients with adult respiratory distress syndrome were treated with veno-venous extracorporeal membrane oxygenation, ECMO, using a heparin-coated system for 8, 12 and 34 days, respectively. Despite extracorporeal blood flow of 4-5 l/min, the patients were ventilator-dependent in the initial period of ECMO. Two of the three patients showed bleeding diatheses despite only slightly elevated activated partial thromboplastin time (APTT). Blood platelet count followed a variable course and serum fibrinogen was normal. Acute pulmonary hypertensive crises, fatal systemic infection, recurrent pneumothorax and plasma leakage from the oxygenators were other main complications during ECMO. Two of the three patients survived, and follow-up showed that severely damaged lungs, if supported in the acute phase, can recover sufficiently to permit normal living.
Adult↗
Isoflurane and intravenous anesthesia used for induction before coronary artery bypass grafting.
Induction of anesthesia with isoflurane in combination with fentanyl, thiopentone, nitrous oxide and pancuronium was studied in nine patients scheduled for coronary artery bypass grafting. Ejection fraction (EF) of the left ventricle was monitored with a single crystal probe linked to a microcomputer, after injection of 200 MBq Tc 99m-HSA. Stroke volume index determined by thermodilution and EF were used to calculate left ventricular end-diastolic volume index (LVEDVI). The degree of ischemia was numerically scored as evaluated from the ECG (modified V5 lead). The study protocol covered seven periods from awake before induction to 5 min after intubation. EF decreased moderately during intubation (P less than 0.05). Systemic vascular resistance index (SVRI) was decreased (P less than 0.05) at all times except during intubation when it was unchanged compared to control. LVEDVI decreased during induction (P less than 0.05), while left ventricular filing pressure remained unchanged. Heart rate did not change. Systolic arterial pressure decreased from 147 mmHg (19.6 kPa) to about 100 mmHg (13.3 kPa) during induction (P less than 0.05). Two patients were given vasoconstrictors because of low arterial pressure. The mean ischemic score did not change. One patient, however, had signs of progressive ischemia. In this patient isoflurane administration was stopped after the last recording and the ECG normalized within 20 min.
Aged↗
Changes in ejection fraction during induction of anesthesia with two different i.v. techniques.
Two intravenous induction techniques were compared with respect to changes in ejection fraction (EF) and central hemodynamics in 30 patients scheduled for coronary artery surgery. Left ventricular EF was measured with a collimated single crystal probe linked to a microcomputer, after injection of 200 MBq Tc 99 m HSA. Stroke volume index (SI) determined by thermodilution and EF were used to calculate left ventricular volume in end-systole and end-diastole. In 20 patients (Group I), anesthesia was induced with diazepam (94 micrograms x kg-1), thiopentone (3 mg x kg-1) and fentanyl (3 micrograms x kg-1). In 10 patients (Group II), fentanyl (30 micrograms x kg-1) was used for induction. In Group I, EF decreased from 0.43 to 0.26 at intubation, while systemic vascular resistance index (SVRI) showed an increase. Left ventricular volume decreased during induction of anesthesia except during intubation. In Group II, EF and left ventricular volume remained unchanged during the study period. SVRI showed no increase at intubation. No change in contractility was indicated from the relation between the end-systolic pressure and volume, in any of the groups.
Anesthesia, Inhalation↗
Comparison of fentanyl and halothane as supplement to nitrous-oxide-oxygen anaesthesia for coronary artery surgery.
Twenty unselected patients suffering from incapacitating angina, in spite of medication with nitrates, beta-blockers and calcium antagonists, were studied before and during coronary artery bypass surgery. Fentanyl or halothane was randomly used in combination with nitrous oxide for maintenance of anaesthesia in order to compare the haemodynamic response to surgery and cardiopulmonary bypass with these two anaesthetic regimens. Systemic and pulmonary artery pressure were kept within normal limits with the aid of volume replacement and/or nitroprusside. The haemodynamic response to surgery and bypass was benign and almost identical in the two groups. Cardiac index increased markedly after bypass (P less than 0.02-0.001) from 2.0 to 3.0 1 X min-1 X m-2 due to an increase in heart rate with no change in stroke index (40 ml X m-2). Oxygen delivery remained unchanged at 17 mmol X min-1 X m-2 in spite of a marked reduction in blood erythrocyte volume fraction (B-EVF), from 38% before bypass to 24% after bypass (P less than 0.001). Oxygen uptake remained unchanged until the end of surgery and did not differ between the groups. Systemic vascular resistance, corrected for the change in viscosity due to the altered B-EVF, was unchanged during the study. No difference was observed between the groups in the relation between pulmonary artery diastolic pressure and left ventricular stroke work index or stroke index, either before or at the end of cardiopulmonary bypass when the patients were transfused from the oxygenator.
Adult↗
Circulatory effects of pancuronium and alcuronium in patients with coronary artery stenosis.
Heart rate and systemic arterial blood pressure were recorded during induction of anaesthesia up to 9 min after endotracheal intubation in 92 patients scheduled for coronary artery bypass surgery, in order to study to what degree the circulatory response to induction of anaesthesia and intubation was modified by different relaxants. Pancuronium (pancuronium bromide) 0.1 mg X kg b.w.-1 and alcuronium (diallyl-nortoxiferine) 0.25 mg X kg b.w.-1 were randomly studied in 36 patients during induction with high-dose fentanyl and in 36 patients induced with thiopentone, diazepam, fentanyl and nitrous oxide. In patients given high-dose fentanyl anaesthesia, systolic blood pressure before, during and after intubation was significantly lower with alcuronium (P less than 0.01). The same difference between alcuronium and pancuronium was observed in balanced anaesthesia before endotracheal intubation. Induction of anaesthesia and intubation were followed by a moderate increase in heart rate, irrespective of the type of anaesthesia and relaxant. Subsequently, 20 patients (10 with high-dose fentanyl and 10 with balanced anaesthesia) were studied. They received pancuronium 0.05 mg X kg b.w.-1 + alcuronium 0.125 mg X kg b.w.-1. This mixture of relaxants produced an intermediate blood pressure response.
Adjuvants, Anesthesia↗
Sequential myocardial depressant and non-depressant anaesthesia for coronary artery surgery.
Patients undergoing coronary artery surgery run a certain risk of developing myocardial infarction in situations with increased myocardial oxygen demand due to e.g. elevations in heart rate and blood pressure. After cardiopulmonary bypass (CPB) there is, however, also the risk of graft occlusion. The present study evaluated the haemodynamic effects of a sequential anaesthesiological technique using halothane 0.5-1.5% in combination with 50% nitrous oxide and droperidol 0.1 mg X kg b.w.-1 before CPB followed by fentanyl 0.2 mg X h-1 in continuous i.v. infusion and diazepam 10-15 mg during and after bypass. Fourteen patients were studied. In seven patients (Group I) halothane was discontinued immediately before CPB and in the following seven patients (Group II) 10-15 min before bypass. The aim was to depress moderately the inotropic state before bypass and to have a normalized myocardial oxygen demand after CPB in order to promote a good flow in the grafts. In Group II mean left ventricular stroke work index (LVSWI) was 0.54-0.79 J X m-2 after bypass as compared to 0.45-0.51 before at comparable filling pressure. Mean left ventricular power index (LVPI) increased from 0.42-0.55 W X m-2 before to 0.73-1.08 after CPB. The patients in Group I showed a similar pattern although with a less marked difference in LVSWI and LVPI values before and after bypass. No correlation was seen between oxygen delivery and oxygen uptake either below or above an oxygen delivery of 15 mmol X min-1 X m-2.
Adult↗
The influence of isoflurane on blood flow in coronary bypass grafts.
The effects of isoflurane on graft blood flow, central hemodynamics and ECG were evaluated in 20 patients during coronary artery surgery in the period immediately after cardiopulmonary bypass (CPB). Intravenous anesthesia with thiopentone, diazepam, fentanyl (continuous infusion), droperidol and pancuronium supplemented with nitrous oxide was used before, and thiopentone and fentanyl were used during CPB. A first measurement of graft flow was performed during fentanyl infusion and the patients were randomly allocated to a control (n = 10) and a study (n = 10) group. In the study group isoflurane was administered in a dose that reduced systolic arterial blood pressure (SAP) to approximately 100 mmHg (13.3 kPa) (inspired concentration 0.5-1.5%) and a second measurement was performed after 30 min. In the control group the infusion of fentanyl was continued. Isoflurane reduced graft blood flow from 52 +/- 5 (mean and s.e. mean) to 40 +/- 5 ml . min-1 (P less than 0.01) concomitant with reductions in SAP, cardiac index, stroke index, left ventricular stroke work index and power index, while these parameters as well as graft flow remained unchanged in the control group. Isoflurane did not produce any change in the degree of ischemia as judged from the ECG. A high blood flow in recently established coronary artery bypass grafts is essential for the prevention of early graft occlusion; therefore the graft-flow-reducing effect of isoflurane has to be taken into consideration when evaluating different anesthetic regimens in the period after CPB.
Aging↗
Effects of intravenous anesthesia on VA/Q distribution: a study performed during ventilation with air and with 50% oxygen, supine and in the lateral position.
Distribution of ventilation and perfusion in relation to ventilation-perfusion ratio (VA/Q) were studied in 14 patients, with a mean age of 59 yr, before elective lung surgery, in the supine position when awake, during intravenous anesthesia and mechanical ventilation with air, after increasing the fraction of inspired oxygen (FIO2) to 0.5, and in the lateral position. Before anesthesia, small inert gas shunts and perfusion of low VA/Q regions, indicating some degree of VA/Q mismatch, were observed in several patients. After induction, FIO2 = 0.21, the major changes were a significant decrease in cardiac output and an increase in log SD for perfusion from 0.77 +/- 0.45 (SD) to 1.13 +/- 0.50 (SD), while the shunt remained low at 1% of cardiac output and arterial oxygen tension (PaO2) was unchanged. An increase to FIO2 = 0.5 induced only small changes with a shunt of 2.5% of cardiac output. In the lateral position, the shunt was 4.0% and increases in ventilation to high VA/Q regions were observed. The lack of marked changes in the VA/Q distribution after induction either could be a result of only minor alterations in the distribution of ventilation and perfusion or an effective vascular response to alveolar hypoxia (hypoxic pulmonary vasoconstriction, HPV).
Adult↗
The effects of an oral combined contraceptive on plasma levels of glucose, free fatty acids, glycerol, D- hydroxybutyrate and triglycerides.
Explore the source record for details and available documents.
Adult↗