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Biomedical subjects

P T Andersen

Publications and source records attributed to P T Andersen.

At least 19 recordsLinked to original sources
PubMed1996

Estimation of pulmonary diffusion resistance and shunt in an oxygen status model.

A compartment model of the transport of oxygen from the alveoli to the tissues is described. In patients with both pulmonary shunt and alveolar resistance to diffusion of oxygen, the model is used to simulate their response to variations in the inspired oxygen fraction. These simulation results are compared to the responses from a patient with respiratory malfunction, indicating that the method can identify patients where not only a pulmonary shunt but also a high alveolar resistance to diffusion of oxygen is clinically significant. Estimation of pulmonary shunt and oxygen diffusion resistance can be done in two different implementations of the model. In the first implementation the estimates are generated by numerical solution of the equations of the compartment model. In the second implementation the equations have been used to construct a causal probabilistic net where biological uncertainties and uncertainties in the measurements can be represented.

Airway Resistance↗
PubMed1991

Postoperative hypophosphataemia and muscle function.

Muscle function tests of the triceps brachii muscle were performed before operation and on the third postoperative day in ten patients undergoing elective cholecystectomy. Electromyograms (EMGs) were recorded by surface electrodes during sustained isotonic and isometric muscle contraction with a constant force of 20 per cent of the preoperative maximal voluntary contraction. Root-mean-square of the EMG was calculated together with the neuromuscular efficiency and measures of the fatiguability. These parameters were compared with changes in the simultaneously measured serum phosphate concentrations. Mean (s.e.m.) neuromuscular efficiency measured after 32-40 s of muscle contraction decreased 14(5) per cent after operation (P less than 0.01), whereas the mean fatiguability of the muscle was unchanged. Mean serum phosphate concentration was 0.87(0.06) mmol/l before operation and 0.79(0.06) mmol/l 3 days after the operation (P greater than 0.05). Two patients developed severe postoperative hypophosphataemia (serum phosphate concentration less than 0.50 mmol/l). Postoperative muscle function deterioration was not associated with changes in the serum phosphate level (P greater than 0.10; r = 0.03). We conclude that patients undergoing cholecystectomy develop postoperative deterioration in skeletal muscle function, which is not associated with serum phosphate concentration.

Adult↗
PubMed1989

Serum and urinary phosphate during and after prolonged muscular ischaemia in non-exercising men and women.

Serum inorganic phosphate (Pi) concentrations and urinary Pi excretions were measured in nine patients undergoing abdominal aortic bypass grafting (group I) and in nine patients undergoing lower limb arterial embolectomy (group II). In group I, serum Pi concentrations were normal until 24 h after reperfusion, when they decreased, reaching their nadir at 48 h (median Pi 0.45 mmol 1(-1). The urinary phosphate clearance relative to the creatinine clearance (Cp/Cc) increased 5 min after reperfusion reaching a maximal median value (0.454) in the 2-24-h collection period. In group II, eight patients had a normal and one had a subnormal serum Pi before reperfusion. None developed hypo- or hyperphosphataemia and the Cp/Cc remained unchanged. Daily urinary Pi excretion was higher in group I than in group II (P less than 0.03). The authors concluded that the regional muscular ischaemia in non-exercising men and women was not associated with hyperphosphataemia. The possible influence of major surgery and anaesthesia on phosphate homeostasis should be considered.

Aorta, Abdominal↗
PubMed1989

Serum creatine kinase-B activity in patients with chronic lower-limb ischemia and after leg amputation.

Serum creatine kinase-B (CK-B) activity was measured and electrocardiograms (ECG) recorded before and after operation in two groups of ten orthopedic patients. Group I underwent lower-limb amputation because of severe, chronic ischemia of the leg and group II (controls) had knee prosthesis implantation or knee ligament surgery. In group I the number of patients with CK-B activities exceeding the discrimination value (0.25 muka-tal/l) for acute myocardial infarction preoperatively and 2, 24, 48, 72 hours, and at 7 days postoperatively were, respectively, three, three, five, three, two and nil. In Group II the serum CK-B activity remained below the myocardial infarction discrimination value in all patients at all times. No ECG abnormalities indicating myocardial infarction appeared in any patient of either group. The study indicates that severe, chronic lower-limb ischemia and amputation of the leg may cause elevation of non-cardiac CK-B activity in serum that can interfere with enzymatic recognition of acute myocardial infarction.

Adult↗
PubMed1988

Complement and leukocyte changes during major vascular surgery.

To gain further insight into the effects of major vascular surgery involving the abdominal aorta on complement and leukocytes, serial measurements of leukocyte and differential counts, plasma concentrations of C3d, and granulocyte elastase bound to alpha1 proteinase inhibitor (E-alpha1PI) were made after aorta declamping in a group of patients not receiving blood or plasma. In the hours after declamping, lymphocyte count decreased, whereas an increase was noticed in leukocytes, neutrophils, and plasma E-alpha1PI. Complement activation was not found. Previous reports on complement activation during aortic surgery probably reflect the administration of blood and plasma during the surgical procedures. Whether aortic cross-clamping or interaction between granulocytes and the aortic prothesis is responsible for the release of lysosomal enzymes during the procedure warrants further studies.

Aorta, Abdominal↗
PubMed1988

Rhabdomyolysis and acute renal failure following an overdose of doxepine and nitrazepam.

A 50-year-old woman developed rhabdomyolysis and myoglobinuric renal impairment after an oral dose of 250 mg nitrazepam and 1,250 mg doxepin. Serum creatinine increased from 70 mumol/l to 472 mumol/l in two days. Serum creatine phosphokinase reached a maximal level of 391 mu kat/l (reference range less than 2.5 mu kat/l) on the third day and serum myoglobin was maximally 910 nmol/l (reference range less than 4.5 nmol/l) on the fourth day after the overdose. Passive and active movements of the knees and ankles became increasingly restricted, but the patient felt no muscle pain. Diuresis decreased to 20-22 ml/hour in spite of repetitive doses of furosemide, but was enforced to greater than 100 ml/hour by vigorous infusion of saline. Haemodialysis was avoided on this regimen. It is suggested that in patients intoxicated with nitrazepam and/or doxepin, rhabdomyolysis should be suspected when a rapidly increasing serum concentration of creatinine is found, even in the absence of muscle pain.

Acute Kidney Injury↗
PubMed1988

Delayed hypercalcemia after non-oliguric acute renal failure associated with rhabdomyolysis.

Alterations in the calcium metabolism are a characteristic paraclinical finding in patients with oliguric acute renal failure associated with rhabdomyolysis. A 20-year-old male operated on under general anesthesia developed non-oliguric acute renal failure due to malignant hyperthermia with rhabdomyolysis (urine myoglobin greater than 20,000 nmol/l; reference range less than 0.85 nmol/l). On the 20th postoperative day hypercalcemia was found, reaching a maximum serum level of 3.74 mmol/l (reference range 2.18-2.65 mmol/l) on the 27th postoperative day. Delayed hypercalcemia in non-oliguric acute renal failure associated with rhabdomyolysis has not been reported previously. This case suggests that prolonged control of the serum calcium level should be performed in patients with rhabdomyolysis, even in the absence of oliguria.

Acute Kidney Injury↗
PubMed1987

Myoglobin and creatine phosphokinase in serum during and after aortic bypass grafting.

In 10 patients undergoing aortic bypass grafting with peroperative aortic cross-clamping we measured the levels of myoglobin and creatine phosphokinase. The duration of peroperative lower limb arterial clamping ranged from 50 min to 95 min. No significant increase in either serum myoglobin or in serum creatine phosphokinase was found during lower limb arterial clamping or for the first two hours after release of ischemia. Both parameters reached a maximum value at 24 hours after release of ischemia, with a median serum myoglobin concentration of 565 micrograms/l (range: 132-2688 micrograms/l) and a median serum creatine phosphokinase activity of 457 U/l (range: 190-1602 U/l). The increase in serum myoglobin and creatine phosphokinase was not associated with the duration of lower limb arterial clamping. Renal impairment was not found in these patients, as evaluated by the serum concentration of beta 2-microglobulin.

Aged↗
PubMed1987

Lower limb transcutaneous oxygen tension during aortic bypass grafting.

Transcutaneous oxygen tension (tcPO2) was measured continuously at the foot of 10 patients during abdominal aortic bypass grafting. Median tcPO2 before surgery was 38.5 mmHg (range: 14-74 mmHg) increasing to 79.0 mmHg (range 44-104 mmHg) after insertion of the vascular prosthesis (p less than 0.01). Eight successful vascular reconstructions were correctly identified intraoperatively. One was correctly identified as failed and one was correctly identified as unchanged compared with the preoperative clinical status. Our results indicate that tcPO2-monitoring may contribute to quality assurance by intraoperative identification of failed or insufficient vascular reconstructions.

Adult↗
PubMed1987

Evaluation of the usefulness of enzymatic diagnosis of myocardial infarction in patients with acute arterial occlusion of the lower extremities.

The serum activities of aspartate aminotransferase, lactate dehydrogenase, creatine kinase and estimated creatine kinase isoenzyme MB (CK-B) were investigated in 12 patients before and after revascularization of ischaemic lower extremities. All patients suffered from sudden lower limb arterial occlusion and underwent embolectomy through a small arteriotomy in the groin. The median serum activity of all four enzymes was elevated before surgery and further increased during the first 24-48 h after revascularization. Median serum activity of aspartate aminotransferase, creatine kinase and lactate dehydrogenase were continuously elevated 7 days after the operation. A high relative CK-B activity coincided in one patient with the development of electrocardiographic evidence of acute myocardial infarction. It is concluded that any of these four enzymes should be used with caution in the diagnosis of acute myocardial infarction before, during or after operation in patients who have sustained prolonged ischaemia of the lower extremities.

Acute Disease↗
PubMed1987

Neuroleptic malignant syndrome during perphenazine treatment.

A 50-year old woman developed symptoms of a neuroleptic malignant syndrome with myoglobinuric renal failure during treatment with perphenazine. After discontinuation of perphenazine and repetitive haemodialysis, the patient recovered. Clinical characteristics of the syndrome, differential diagnosis and various therapeutic possibilities are shortly reviewed.

Acute Kidney Injury↗