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Biomedical subjects

M Arola

Publications and source records attributed to M Arola.

28 records · Page 2Linked to original sources
PubMed1985

Midazolam kinetics before, during and after cardiopulmonary bypass surgery.

Gas-chromatographically determined serum concentrations of midazolam were recorded before, during and after cardiopulmonary bypass in patients scheduled for a coronary artery bypass grafting operation. Following single 0.075 mg/kg (n = 6) and 0.15 mg/kg (n = 6) intravenous injections of midazolam, a mean distribution phase half-life of 3.4 and 4.4 min respectively was calculated. At the establishment of the bypass, a rapid drop in the concentration of midazolam was observed followed by a significant increase in concentration during the postperfusion period. The apparent mean elimination phase half-life (281 min) of midazolam was longer than that (about 120 min) measured in earlier works in young, healthy subjects. Thus the metabolism of midazolam during the postperfusion period appears to be slower.

Benzodiazepines↗
PubMed1984

Lorazepam and high-dose fentanyl anaesthesia: effects on haemodynamics and oxygen transportation in patients undergoing coronary revascularization.

The effects of intravenous lorazepam (0.05 mg/kg) on haemodynamics and oxygen transportation were studied in a group of 11 patients undergoing a coronary artery bypass grafting operation with high-dose fentanyl anaesthesia and compared to the changes in another group of 11 patients receiving the same anaesthesia, but saline instead of lorazepam. The measurements were made under stable haemodynamic conditions before the injection of lorazepam or saline, and repeated 5, 20 and 40 min after the injection. Lorazepam caused a slight decrease in the systemic and pulmonary arterial pressures and in the left ventricular stroke work index, as compared to the control group. The ECG or the rate-pressure product did not show changes indicative of myocardial oxygen supply/demand imbalance in either group. There was a similar decrease in the systemic oxygen transportation and an increase in the arterio-venous oxygen content difference in both groups, but the unchanged systemic oxygen consumption and arterial lactate level suggest a well-maintained tissue oxygenation. It is concluded that intravenous lorazepam does not cause important haemodynamic untoward effects as an adjunct to high-dose fentanyl anaesthesia in patients undergoing coronary artery bypass grafting.

Adult↗
PubMed1984

Metoprolol medication and coronary artery bypass grafting operation.

Twenty patients undergoing a coronary artery bypass grafting operation with high-dose fentanyl anaesthesia, all on long-term metoprolol medication, were randomly divided into a metoprolol group (last metoprolol dose given 1.5 h before the anaesthesia) and a control group (last metoprolol dose 12 h before the anaesthesia). Haemodynamics were measured and the ECG was recorded serially in order to compare the responses to the anaesthesia induction and skin incision in these two groups and to evaluate possible harmful effects of the maintained metoprolol medication. The ECG showed ischaemic signs in five control group patients during the anaesthesia induction; these patients also had a relatively high rate-pressure product. No metoprolol group patient developed ECG changes indicative of ischaemia at this stage, despite a low plasma metoprolol concentration in two patients. Surgical stimulation caused no signs of myocardial ischaemia in either group. There were no inter-group differences in the haemodynamics or oxygen transportation. No harmful effects of the maintained metoprolol on the post-bypass cardiac performance nor on the occurrence of rhythm or conduction disturbances could be seen, although a high plasma metoprolol concentration was maintained in several metoprolol group patients over the bypass time. It is concluded that continuation of long-term metoprolol medication up to 1.5 h before high-dose fentanyl anaesthesia for coronary artery bypass grafting has no harmful effects on the haemodynamics during the operation or the restoration of the cardiac function after the cardiopulmonary bypass, but it evidently does help to maintain the myocardial oxygen supply/demand balance during the anaesthesia induction.

Anesthesia, Intravenous↗
PubMed1984

Midazolam as adjunct to high-dose fentanyl anaesthesia for coronary artery bypass grafting operation.

The usefulness of midazolam as an adjunct during high-dose fentanyl anaesthesia was studied by following the changes in the haemodynamics and total body oxygenation after an intravenous injection of 0.075 mg/kg and 0.15 mg/kg of midazolam during the induction of fentanyl (75 micrograms/kg)-oxygen anaesthesia for a coronary artery bypass operation. These responses were then compared to the changes seen in patients receiving the same fentanyl anaesthesia without the midazolam. A rapid decline after the midazolam injection was seen in the mean systemic arterial pressure (24-32%--the lowest individual value was 45 mmHg (6.0 kPa)) and in the systolic and diastolic pulmonary arterial pressures (29-33% and 30-31%) in 1-3 min. As measured 10 min after the midazolam injection, a decrease from the baseline was seen in the stroke index (25-30%), in the left ventricular stroke work index (46-42%) and in the right ventricular stroke work index (48-61%). These haemodynamic variables remained on a lower level throughout the study period (40 min) in the midazolam patients as compared to the controls. The tissue oxygenation seemed to be sufficient in all groups during the study period. An intravenous injection of a relatively low dose of midazolam during the induction of high-dose fentanyl anaesthesia seems to be followed by rapidly increased venous pooling and a moderately to severely decreased systemic arterial pressure. Based on the results of this study, midazolam cannot be recommended as an adjunct during high-dose fentanyl anaesthesia.

Adult↗
PubMed1982

Effect of age and cardiopulmonary bypass on the pharmacokinetics of lorazepam.

The pharmacokinetics of lorazepam after 0.03 mg/kg intravenous administration was investigated in 14 surgical patients (nasal surgery under local anaesthesia) ranging in age from 25 to 86 years (8 males and 6 females). No statistically significant changes in the kinetics of lorazepam associated with the aging process were found. In these premedicated patients a slow onset of the drug action of lorazepam was assessed both subjectively and objectively with no apparent relationship to the age. These findings are of potential clinical importance, because it is highly desirable to use drugs for which age-related alterations are of minimum degree. In 5 male patients undergoing surgery with cardiopulmonary bypass, lorazepam disappeared from the plasma after a single 4 mg intravenous injection with an apparent comparable half-life (10.0 +/- 3.2 min.) to that of the above mentioned surgical patients. The concentrations of both unconjugated and conjugated lorazepam dropped abruptly at the start of extracorporeal circulation followed by an increase in the postperfusion period. After this peak effect the mean apparent half-life of lorazepam was 15.5 +/- 5.8 hours of indicating no great change in its elimination in comparison with patients operated under local anaesthesia (half-life 12.1 +/- 3.7 hours). Pharmacokinetically, lorazepam appears to be a useful agent in connection with cardiopulmonary bypass operation.

Adult↗
PubMed1980

Combined alpha- and beta-blockade with labetalol in post-open heart surgery hypertension. Reversal of hemodynamic deterioration with glucagon.

The hemodynamic effects of intravenous labetalol (a combined alpha- and beta-blocking agent) were studied in 11 patients during early post-open heart surgery hypertension. With a mean dosage of 15 mg, labetalol reduced both systemic arterial pressures and the heart rate by an average of 21 percent (p < .001). The patients failed to compensate for the decline in pressure and pulse rate by elevation of their stroke volume, and even the cardiac index (CI) was severely depressed (from 2.30 to 1.67 L/min/m2, ie, 27 percent; p < .001). Neither left ventricular filling pressure nor vascular resistance was affected by labetalol early after open heart surgery. In four patients, 3 mg of glucagon after administration of labetalol elevated pulmonary arterial pressures and increased the CI by 16 percent. Two patients were observed on the preoperative day, and their response to labetalol was similar to that described in earlier studies: during blood pressure decline, CI was slightly augmented, and the systemic vascular resistance was greatly reduced (26 percent). The results indicate that after open heart surgery, patients are highly sensitive to the beta-blocking effects of labetalol, and although labetalol can greatly reduce myocardial oxygen consumption, it cannot be recommended for the treatment of post-open heart surgery hypertension.

Adult↗
PubMed1976

[Thymectomy in myasthenia gravis (author's transl)].

10 myasthenia patients were treated surgically during a four year period, 1970 TO 1973. Thymectomy was only resorted to in the most severe cases of the disease. A sternum splitting incision was preferred. Postoperative diffculties were usually avoided by routine use of a volume-controlled respirator. Oro-tracheal intubation was preferred to tracheostomy in order to avoid infection. In 9 patients it was possible to reduce the daily dose of medicine. Clinical improvement, sometimes delayed, occurred in 8 patients. All the patients had been incapacitated preoperatively but in 6 cases they were able to return to work. The mortality rate was nil. There was one case of postoperative pneumonia and one delayed sternal union.

Evaluation Studies as Topic↗
PubMed1976

Experiences with the Björk-Shiley tilting disc valve in aortic and mitral valve surgery.

During a four-year period, aortic or mitral valve replacements with the Björk-Shiley tilting disc valve were performed in 114 cases. The series comprises 75 aortic, 34 mitral and 5 double valve replacements. In the aortic valve group (AVR) concomitant resection of the ascending aorta (cystic medial necrosis aneurysm)) was carried out in 5 cases, aortocoronary bypass in 2 cases and closure of a VSD in one case. Antibiotic prophylaxis and postoperative anticoagulant treatment were used routinely. The hospital mortality rates were6 8.0% in the AVR-group (single aortic valve mortality 7.1 %), 8.8% in the MVR-group and 60% in the double valve group. Late mortality in the AVR-group was 2.8%. There were no late thromboembolic complications in this group. Aortography showed grade II--III regurgitation (paravalvular leaks) in 15 % of the cases. In the MVR-group the late mortality was 9.7%. One patient died because of malfunction (thrombosis) of the prosthesis. The thrombotic complication was obviously caused by discontinuation of anticoagulant therapy. The clinically estimated functional capacity NYHA classification) improved considerably, especially in the MVR-group.

Adolescent↗