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Biomedical subjects

G Settergren

Publications and source records attributed to G Settergren.

23 records · Page 2Linked to original sources
PubMed1985

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↗
PubMed1977

Total parenteral nutrition in infants. Blood levels of glucose, lactate, pyruvate, free fatty acids, glycerol, d-beta-hydroxybutyrate, triglycerides, free amino acids and insulin.

Two regimens (A and B) for TPN were designed to meet the requirements of newborn infants for calories, amino acids, fatty acids, electrolytes, trace elements and vitamins. Both "A" and "B" included fat emulsion (Intralipid). "A" contained fructose and glucose, "B" glucose only. "A" provided amino acids (Vamin) in proportions similar to those of whole egg, "B" similar to those of human milk. All nutrients were given simultaneously into peripheral veins by constant infusion. Nineteen patients (11 newborns, 8 infants) were studied for 1-28 days. Twelve infants recovered, 7 died. In none could TPN be regarded as the cause of death. Treatment was complicated by sepsis in 5 infants. During the course of treatment, blood levels of substrates and insulin were measured before, during and 30 min after discontinuation of TPN. Highly raised concentrations of circulating substrates seen in 3 infants seemed to be related to a poor clinical condition rather than to the regimen used. Infants in good condition tolerated TPN well. Low levels of branch-chained amino acids and tendency to ketonemia, when infusion was stopped, suggested that minimal rather than optimal supply of energy and of amino acids in relation to energy was provided with both regimens. Low insulin levels associated with elevated blood levels of substrates suggested that insulin administration to selected cases might be indicated. Fructose (0.30 g/kg X hour-1) given with regimen A increased blood lactate concentrations. Homocystinaemia appeared in 2 cases; disappearance after excess vitamin B6 administration indicated increased B6 requirement.

Amino Acids↗
PubMed1976

Cerebral blood flow and exchange of oxygen, glucose, ketone bodies, lactate, pyruvate and amino acids in infants.

Cerebral blood flow (CBF) and cerebral av-differences of oxygen and circulating substrates were measured in normocapnic infants during general anaesthesia before elective surgery in order to study possible age-dependent variations. CBF was determined by a minor modification of the Kety-Schmidt technique from desaturation curves of nitrous oxide (N2O) in arterial and cerebral venous blood (N2O analysed by gas chromatography on 15 mul blood samples) after reduction of inhaled N2O from 75 to 50%. The reproducibility was +/-4.6%. Lactate, pyruvate and oxygen were determined in whole blood and amino acids in plasma by ion-exchange chromatography. Reliable av-differences of glucose, acetoacetate and D-beta-hydroxybutyrate could be calculated from plasma values and hematocrits. Mean values from 12 infants (age 11 days-12 months) were: CBF 69 ml/100 g0min-1; cerebral uptake (in mumoles/100 g-min-1): oxygen 104, glucose 27, acetoacetate 0.9, D-beta-hydroxybutyrate 2.3; cerebral release: lactate 2.4 and pyruvate 0.8. Significant uptake of amino acids was found only for histidine 0.95 and arginine 0.7. Significant correlations between arterial concentration and cerebral exchange were found for: ornithine, arginine, phenylalanine, aspartic acid, serine, glutamine and acetoacetate. CBF and substrate exchange were unrelated to age within the group. Infants had higher mean CBF and greater uptake of ketone bodies than has been reported in adults.

Acetoacetates↗