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Biomedical subjects

T Pedersen

Publications and source records attributed to T Pedersen.

At least 127 records · Page 7Linked to original sources
PubMed1984

Effect of vecuronium and pancuronium on cardiac performance and transmural myocardial perfusion during ketamine anaesthesia.

The haemodynamic effects of vecuronium and pancuronium were studied in 20 healthy patients during diazepam/ketamine anaesthesia. Anaesthesia was induced with glycopyrrolate 3 micrograms/kg, diazepam 0.3 mg/kg and ketamine 1.0 mg/kg as a bolus and 1.0 mg/kg over 10 min. After induction, anaesthesia was maintained with ketamine infusion 1.0 mg/kg/h. The lungs were ventilated with 50% nitrous oxide in oxygen. Equipotent doses of vecuronium (74 micrograms/kg) or pancuronium (99 micrograms/kg) were administered for intubation. The thoracic impedance, ECG and phonocardiogram were recorded during the induction of anaesthesia. The results suggest that vecuronium has no cardiovascular effects during ketamine anaesthesia, whereas pancuronium due to its chronotropic effect, causes a deterioration in left ventricular performance.

Anesthesia, General↗
PubMed1984

Cardiac performance measured by impedance cardiography and radionuclide angiography.

Impedance cardiography is used for non-invasive determinations of stroke volume and myocardial oxygen balance predicted from diastolic Pressure Time Index (DPTI) as an estimation of oxygen supply and Systolic Pressure Time Index (SPTI) as an estimation of oxygen demand. The model which is described assesses the cardiac performance and is compared with previously known methods. In recent years the radionuclide technique for measurement of left ventricular ejection fraction (LVEF) has increased. A comparison has been made between impedance cardiography and the radionuclide angiography technique in order to determine the value of impedance cardiography during rapid changes in cardiac performance. Further previous studies have shown a good relationship between the values for impedance stroke volume and the thermodilution technique, and a very high correlation after individual analysis. The method should be suitable for relative measurements of stroke volume; however, the method appears of little value for estimation of absolute values. Our group has shown a fairly good correlation in cardiac performance in a comparative study between impedance cardiography and radionuclide angiography during prenalterol infusion. In conclusion, impedance cardiography is a method which simultaneously gives information about variations in cardiac stroke volume. Additional information is gained from the DPTI/SPTI - ratio, which can assess the myocardial oxygen balance and signify subendocardial underperfusion. The method may be considered as a valuable monitoring tool for repeated determinations of myocardial function.

Blood Pressure↗
PubMed1983

Effects of prenalterol on cardiac performance and transmural myocardial perfusion in patients with chronic renal failure.

The acute haemodynamic effects of the beta-adrenoreceptor agonist, prenalterol, were studied in six patients with chronic end-stage renal failure. Prenalterol 0.8 mg, 1.6 mg, and 3.2 mg was administered i.v. as a bolus, and after the last dose the selective adrenergic beta-1-receptor antagonist metoprolol was administered i.v. in doses of 5 and 10 mg. The haemodynamic effects of the drugs were investigated using impedance cardiography and radionuclide angiocardiography. The main haemodynamic effects were a dose-related chronotropic effect, demonstrated by an increase in heart rate (26%; less than 0.05), and an inotropic effect, shown by an increase in stroke volume index (20%; p less than 0.05) and left ventricular ejection time (12%; p less than 0.05); the cardiac index was increased by 47% (p less than 0.05). Transmural myocardial perfusion (DPTI/SPTI ratio) was decreased by 22% (p less than 0.05) after prenalterol. It is concluded that prenalterol has positive inotropic and chronotropic effects in patients with chronic renal failure, that the improvement in left ventricular performance is at the expense of a decreased transmural myocardial perfusion, and that metoprolol is a specific antidote.

Aged↗
PubMed1983

Initial treatment of acute pancreatitis.

Fifty patients with mild to moderately severe acute pancreatitis of various causes were randomly allocated to treatment with either nasogastric suction and intravenously administered fluids (SD) or the oral intake of clear fluids (FF). No significant difference was found between the two groups as far as abdominal pain, abdominal tenderness, degree of hyperamylasemia and hospital stay were concerned. Mortality and such complications as pancreatic abscess, pseudocyst and persisting hyperamylasemia occurred equally in both groups. The findings suggest that nasogastric suction and intravenously administered fluids provided no advantage compared with a simple therapy, consisting of the oral intake of fluids ad libitum in the treatment of patients with mild to moderately severe pancreatitis of various causations.

Abdomen↗
PubMed1983

Effect of hemodialysis on cardiac performance and transmural myocardial perfusion.

The effects of hemodialysis on cardiac performance and myocardial oxygen balance were evaluated by impedance cardiography in 16 patients with end-stage renal failure treated with regular hemodialysis. Cardiac symptoms and/or failure were present in 8 patients (group A) whereas 8 patients (group B) had no signs of heart dysfunction. The hemodialysis were carried out without ultrafiltration so that the body weight was the same before and after dialysis. The two groups did not differ significantly with regard to either biochemical values or hemodynamic parameters before dialysis. During dialysis mean cardiac output (CO) increased significantly 7.1 +/- 2.8 l/min to 9.1 +/- 3.6 l/min (P less than 0.01), mainly in patients group A, and was maximum after 90 min. The myocardial oxygen balance estimated from the supply/demand ratio (DPTI/SPTI) was significantly reduced after 20 min from 1.14 +/- 0.16 to 0.99 +/- 0.12 (P less than 0.01). After 60 min DPTI/SPTI decreased to its lowest value due to an excess of myocardial oxygen demand (SPTI) over myocardial oxygen supply (DPTI), signifying a transitory underperfusion of the subendocardium which occurred mainly in patients with cardiac failure (group A). Mean arterial blood pressure remained unchanged whereas mean heart rate increased significantly after 90 min and remained raised throughout the rest of dialysis (78.8 +/- 10.4 bpm to 87.1 +/- 12.6 bpm [P less than 0.01]). Total peripheral resistance (TPR) was decreased significantly after 5 min (P less than 0.01), but subsequent falls were not significant. Changes in the DPTI/SPTI ratio showed that the improvement in left ventricular performance was at the expense of myocardial oxygen balance, which caused a greater incidence of myocardial underperfusion, particularly in patients with cardiac failure.

Adult↗
PubMed1982

Effects of low-dose ketamine and thiopentone on cardiac performance and myocardial oxygen balance in high-risk patients.

Induction of anaesthesia may pose a significant hazard to patients with critical cardiovascular status. Ketamine has been advocated as the drug of choice for maintaining cardiovascular performance during induction of anaesthesia in severely ill surgical patients. The purpose of this study was to compare the relative changes in the haemodynamic effects of ketamine and thiopentone during the first 30 min of anaesthesia induction measured by thoracic impedance cardiography. Twelve adult high-risk surgical patients, ASA class III-V, were induced with thiopentone and fentanyl or with infusion of ketamine. Cardiac output decreased to 69% in the thiopentone group (P less than 0.05), but was hardly affected in the ketamine group. The pre-ejection period to left ventricular time (PEPI) and the pre-ejection period index ratio increased significantly after thiopentone (P less than 0.05), while ketamine caused only minimal changes in left ventricular performance. The diastolic pressure time index to systolic pressure time index ration decreased significantly in both groups.

Adult↗
PubMed1982

Protective choledochoduodenostomy in multiple common duct stones in the aged.

Forty-nine patients more than 70 years of age had a follow-up examination two to eight years after choledochoduodenostomy for common duct stones or for common duct strictures following a previous biliary tract operation. Death followed operation in two patients and was not related to the choledochoduodenostomy itself. Results of the follow-up examination revealed that none of the patients had had signs or symptoms of cholangitis, jaundice or episodes of fever. One patient only had recurrent, but mild, biliary colic. Choledochoduodenostomy is well tolerated in old age and justified in elderly patients with multiple stones in dilated common ducts as a precaution against retained or recurrent common duct stones.

Age Factors↗
PubMed1982

The value of conventional barium enema of the colon in patients with haemorrhoids.

A conventional barium enema of the colon was performed in 300 patients with haemorrhoids referred to a surgical department. No malignancies were detected by X-ray, while one cancer of the rectum was revealed by sigmoidoscopy. It is concluded that barium enema should not be used as a routine but only in patients with symptoms which cannot be explained by haemorrhoids.

Adult↗
PubMed1981

Ketamine as continuous intravenous infusion combined with diazepam in non-abdominal surgery. A randomized double-blind study.

Sixty-four women undergoing non-abdominal operations were anaesthetized with ketamine administered as continuous intravenous drip combined with diazepam. A double-blind, controlled study was done to assess the dosage, the cardiovascular stimulation, and whether psychotomimetic side effects could be reduced. At induction ketamine was given in a dose of 2 mg/kg in combination with diazepam/placebo 10 mg i.v. The infusion was maintained at 2-6 mg/min. The dose of ketamine during the anaesthesia was significantly reduced by diazepam, from 4.51 mg/min to 3.55 mg/min (p less than 0.001). The sympathomimetic effect of ketamine was significantly reduced by diazepam, as the increase in pulse rate as well as in blood pressure was diminished (p less than 0.05). The frequency of hallucinations dropped from 30.0% to 2.9% with diazepam, while the total frequency of psychotomimetic side effects fell from 36.6% to 11.8% (p less than 0.05). As this frequency of the psychotomimetic side effects still seems to be high with this method, it cannot be recommended to use a continuous drip of ketamine for routine operations on adults. On the other hand, ketamine infusion was found to produce favourable haemodynamic conditions, and this technique seems to be useful in poor-risk and hypovolaemic patients.

Adult↗