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Biomedical subjects

L W Andersen

Publications and source records attributed to L W Andersen.

36 records · Page 2Linked to original sources

Endotoxemia and enhanced generation of oxygen radicals by neutrophils from patients undergoing cardiopulmonary bypass.

Plasma endotoxin concentrations and oxidative burst response of peripheral blood polymorphonuclear leukocytes were examined in 12 patients undergoing coronary artery bypass. The measurements were made just before the operation, 5 minutes after removal of the aortic crossclamp, and 24 hours after the operation. Endotoxin was quantitated by a combination of a sensitive Limulus amebocyte lysate assay and rocket immunoelectrophoresis measuring picogram amounts of endotoxin. Peripheral blood neutrophils were purified by a two-step dextran sedimentation and metrizoate sodium Ficoll (Lymphoprep., Nyegaard, Oslo, Norway) centrifugation. The oxidative burst response of these cells was measured for their ability to generate superoxide anion and was determined by a cytochrome c reduction assay. Preoperatively, all the plasma samples except one were free of endotoxin. The endotoxin levels reached 100 pg/ml 5 minutes after removal of the aortic crossclamp, and except in one sample they had decreased 24 hours after the operation. Studies on the generation of superoxide by neutrophils showed a decline in the response 5 minutes after removal of the aortic crossclamp and an enhancement of the response to f-Met-Leu-Phe by cells obtained from 11 of 12 patients 24 hours postoperatively. In vitro addition of bacterial lipopolysaccharide to blood from healthy individuals also enhanced the superoxide response of the neutrophils. We conclude that during cardiopulmonary bypass the circulating blood is contaminated by endotoxin and the neutrophils are primed for enhanced generation of oxygen radicals. The released oxygen radicals may be involved in the tissue damage observed in these patients.

Aged↗

Concentrations of thiopentone in mature breast milk and colostrum following an induction dose.

In two groups of eight patients, concentrations of thiopentone in mature breast milk and colostrum following anaesthesia induction with 5.4 and 5.0 mg kg-1 b.w. (mean), respectively, were measured in the first 36 h postoperatively. Blood concentrations were measured simultaneously. The maximal concentrations were: in mature breast milk, 3.4 +/- 0.68 mumol l-1 (mean +/- s.e. mean) (0.090 mg 100 ml-1), and in colostrum, 1.3 +/- 0.5 mumol l-1 (0.034 mg 100 ml-1). The milk/plasma ratio was less than 1.0 in both groups. The above concentrations may be regarded as negligible and therefore non-toxic for the nursing infant.

Adult↗

Extreme metabolic acidosis. Case report.

A 42-year-old male patient, who suffered from insulin-dependent diabetes mellitus (IDDM) and intolerance of lactose, presented with extreme metabolic acidosis (lactic acidosis). On arrival, an arterial blood sample showed: pH 6.79, PO2 18.8 kPa, PCO2 0.9 kPa, base excess-33 mmol l-1, blood glucose 38 mmol l-1 and oesophageal temperature 30 degrees C. Apart from the uncontrolled hyperglycaemia, a fluid balance disorder elicited by diarrhoea and disturbed tissue perfusion were possible aetiological factors. The patient was treated with a low-dose insulin regimen and infusion of isotonic sodium bicarbonate with a satisfactory result.

Acidosis↗

Presence of circulating endotoxins during cardiac operations.

Ten patients having coronary artery bypass grafting were intraoperatively and postoperatively analyzed for endotoxins with the Limulus amoebocyte lysate test. A new highly sensitive rocket immunoelectrophoretic assay for reading the reactions of endotoxins with Limulus amoebocyte lysate was used. Preoperatively, all blood samples from the patients had negative Limulus amoebocyte lysate tests, negative blood cultures, normal total white cell counts, and were clinically without signs of infection. Intraoperatively, a substantial amount of endotoxins were found in samples from the extracorporeal circuit, the pulmonary artery, and the cardiac suction lines, which persisted during the cardiopulmonary bypass. The endotoxin content decreased significantly (p less than 0.05) 6 hours after cardiopulmonary bypass and further decreased within the seventh postoperative day (p less than 0.01). A positive Limulus amoebocyte lysate test was also found in some of the fluids administered during the operation, that is, the cardioplegic fluids, the priming fluids for the extracorporeal circuit, the blood transfusions, and the ice for local cooling. Postoperatively, all patients had rectal temperatures below 38.5 degrees C, but no correlation was found between the magnitude of endotoxin content and the degree of fever. Only one of the patients had positive blood cultures. Despite the measured endotoxin content, no intraoperative or postoperative complications were found.

Aged↗

Lidocaine given intravenously as a suppressant of cough and laryngospasm in connection with extubation after tonsillectomy.

The preventive effect of lidocaine against coughing in the recovery period after general anaesthesia was observed. The study was carried out as a double-blind sequential trial. At the same time the incidence of laryngospasm was registered. Lidocaine or placebo was given intravenously just before extubation. Nineteen patients for tonsillectomy, all of them over the age of 15, randomly received a 2% solution of lidocaine 2 mg/kg body weight or placebo (saline) 2 min prior to expected extubation. We found that lidocaine in this dose given prophylactically just before extubation was able to inhibit and prevent coughing in the recovery period after general anaesthesia. None of the patients included in this study got laryngospasm, and none of the patients developed serious side-effects.

Adolescent↗