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Biomedical subjects

H Stjernström

Publications and source records attributed to H Stjernström.

29 records · Page 2Linked to original sources
PubMed1986

Kinetics of carbon dioxide during cardiopulmonary resuscitation.

CO2 kinetics during CPR was investigated in 15 anesthetized piglets. BP, blood gases, and acid-base balance were monitored through catheters in the carotid artery and a central vein, as well as in cerebrospinal fluid. Cardiac arrest was induced by a transthoracic direct current shock. CPR was begun immediately by artificial ventilation and simultaneous external chest compressions. Epinephrine was administered after 8 min of CPR. One group (n = 5) of animals received no buffer treatment while another (n = 5) received an infusion of 75 mmol sodium bicarbonate and a third group (n = 5) received an equivalent amount of tris-buffer mixture. The results of these experiments, as well as previously described circulatory variables during CPR, were analyzed using a computer model describing the CO2 kinetics of the pig. Our main finding was that PaCO2 was positively correlated to cardiac output during CPR; improved cardiac output during CPR resulted in more efficient tissue CO2 elimination and was associated with increased survival rates. PaCO2 was also somewhat reduced by efficient alveolar hyperventilation. The arterial PCO2 and pH did not reflect the acid-base balance in peripheral tissues. During CPR, bicarbonate and tris-buffer mixture both quickly passed through the blood-brain barrier. When buffer treatment is indicated during CPR, a buffer which does not increase tissue PCO2 may be the drug of choice.

Acid-Base Equilibrium↗
PubMed1986

The influence of abdominal surgery on the splanchnic exchange of amino acids.

The splanchnic exchange of amino acids was studied during and immediately after elective cholecystectomy in 10 patients given a constant infusion of glucose (1.1 mmol/min). Measurements of splanchnic blood flow and arteriohepatic venous differences of plasma amino acids, glucose, lactate and glycerol were made preoperatively, intraoperatively and twice in the immediate postoperative period. The arterial plasma concentration of most amino acids declined during and after surgery but the arterial concentration of alanine was highest in the postoperative period. The total splanchnic uptake of amino acids increased from 140.3 +/- 36.0 mumol/min preoperatively to 338.2 +/- 51.7 mumol/min postoperatively (p less than 0.05). Alanine and glutamine accounted for 65-70% of the total splanchnic uptake of amino acids throughout the investigation. The fractional extraction of methionine increased in the immediate postoperative period, while the fractional extraction of the remaining amino acids was stable. The splanchnic uptake of gluconeogenic substrates exceeded the splanchnic glucose release. The splanchnic uptake of amino acids had already increased intraoperatively and further increased postoperatively despite a net splanchnic glucose uptake in this period.

Abdomen↗
PubMed1985

Post-operative substrate utilisation and gas exchange using two different TPN-systems: glucose versus fat.

Twenty patients were studied over the first 4 post-operative days following abdominal aortic surgery. Ten patients had 93% of their non-protein energy as glucose and insulin was given to keep blood glucose below 10 mmol/l. The other 10 patients had 80% of non-protein energy as fat (Intralipid). Amino acids corresponding to 12 g of nitrogen were given in both groups. Gas exchange, nitrogen balance, phosphate balance, vanillylmandelic acid (VMA) excretion, 1- and 3-methylhistidine in urine, acute phase proteins, immunoglobulins and albumin were followed. Substrate utilisation was calculated from indirect calorimetry data and nitrogen excretion. Metabolism in the early post-operative phase was found to adapt to the nutrition regimen given even though the composition was extreme either in fat or carbohydrate content. The glucose-insulin regimen had a better nitrogen sparing effect and based on the difference in 3-methylhistidine excretion it is suggested that mainly protein muscle benefitted from this. Regardless of the TPN-regimen given, those patients whose RQ deviated the most from the average in their group had the highest nitrogen excretion. The two groups showed no differences in plasma proteins and catecholamine excretion.

Journal Article↗
PubMed1985

Glucose balance and muscle glycogen during TPN in the early post-operative phase.

In order to study how muscle glycogen is influenced by different nutritional regimens in the early post-operative period we took muscle biopsies from 20 patients preoperatively and on the fourth post-operative day after abdominal aortic surgery. Ten patients received 93% of non-protein energy as glucose, 7% as fat (Intralipid) and insulin was given to keep the blood glucose below 10 mmol/l. The remaining patients had 80% of non-protein energy as fat (Intralipid). Amino acids constituting 12 g of nitrogen daily were given to both groups. Daily measurements of gas exchange (oxygen uptake, CO2-production) were performed and from these data glucose balance was calculated as the difference between glucose intake and glucose expenditure. Muscle biopsies were analysed for glycogen, adenosine triphosphate, glucose-6-phosphate, lactate and citrate. We found that it was possible to maintain muscle glycogen stores at pre-operative levels with a glucose-insulin regimen. With the fat regimen there was a 31% decrease in muscle glycogen and two patients had a negative glucose balance despite the fact that 150 g of glucose were given. Average glucose balance throughout the study correlated positively with glucose intake. A significant correlation between glucose on the third day and change in muscle glycogen content was found. Muscle content of adenosine triphosphate, glucose-6-phosphate, lactate and citrate were similar in both groups.

Journal Article↗
PubMed1985

Effects of a thermal ceiling on postoperative hypothermia.

Moderate per- and postoperative hypothermia initiates an increased metabolism in the postoperative period. The subsequent demands on oxygen transport may be critical in poor risk patients. Nineteen healthy young women with moderate hypothermia after abdominal surgery were studied for 2 h postoperatively with or without external heating from a heating ceiling. Central and peripheral temperatures, oxygen consumption, plasma catecholamines and shivering were measured. A method for continuous measurement of oxygen consumption and carbon dioxide production during spontaneous breathing is described. The results suggest that postoperative external heating decreases oxygen consumption, shivering and plasma catecholamine levels. At the same time, the comfort of the patient is increased considerably.

Adult↗
PubMed1985

Thermal balance during transurethral resection of the prostate. A comparison of general anaesthesia and epidural analgesia.

Heat loss during anaesthesia and surgery is a common problem. In patients with restricted cardio-pulmonary reserves this may endanger the postoperative outcome. In order to compare thermal balance we studied 25 men undergoing transurethral resection of the prostate (TURP), using either general anaesthesia (G.A.) or epidural analgesia (E.A.). Oxygen uptake, catecholamines, peripheral and central temperatures were followed in the per- and postoperative period. Heat production and total body heat were calculated from oxygen uptake and temperature measurements, respectively. Transurethral resection of the prostate resulted in a peroperative heat loss which was not influenced by the anaesthetic technique used and averaged 370 kJ during the first hour of surgery. G.A. reduced heat production while this was uninfluenced by E.A. After termination of general anaesthesia, oxygen uptake and plasma catecholamines increased, while no such changes could be detected using epidural analgesia. The ability to increase mean body temperature by increasing heat production was negatively correlated to age.

Age Factors↗
PubMed1981

Influence of abdominal surgical trauma upon some energy metabolites in the quadriceps muscle in man.

Thirteen patients with gallbladder disease but otherwise healthy were studied in connection with cholecystectomy. Specimens of the lateral vastus muscle were taken by the percutaneous needle biopsy technique during anesthesia before surgery, on two occasions during surgery and 30 min after discontinuation of anaesthesia. The muscle samples were analysed for glycogen, lactate, citrate, ATP, phosphoryl creatine, creatine and water content. Citrate and lactate concentrations in muscle increased continuously throughout the study. There were no significant changes in the concentration of glycogen, phosphoryl creatine, and ATP in muscle tissue. The increase in citrate concentration is probably related to an augmented uptake and combustion of free fatty acids and 3-hydroxybutyrate in this situation. The data suggest that during anaesthesia and abdominal surgery an increase in the muscle citrate concentration may contribute to the modulation of carbohydrate utilization in skeletal muscle.

Abdomen↗
PubMed1981

Influence of abdominal surgical trauma and intra-operative infusion of glucose on splanchnic glucose metabolism in man.

Abdominal surgery increases blood glucose concentration and peripheral release and splanchnic uptake of gluconeogenic substrates, including alanine. During trauma or sepsis, infusion of glucose fails to depress alanine conversion to glucose. The effect of intra-operative glucose infusion on splanchnic metabolism was examined in the present study. In eight patients undergoing elective cholecystectomy, splanchnic glucose metabolism was investigated before, during and immediately after surgery. Glucose was infused at a constant rate of 1 mmol/min. Splanchnic blood flow and arterio-hepatic venous differences of oxygen, glucose, lactate, glycerol, 3-hydroxybutyrate and alanine were measured. Eight other patients, who received saline instead of glucose, served as a control group. Infusion of glucose resulted in total inhibition of splanchnic glucose release before as well as during and immediately after surgery. This was observed, even before surgery, at an arterial glucose level which was lower than that in the control group at the end of and immediately after surgery, at which no decrease of the splanchnic glucose release was recorded. changes in neuronal and hormonal factors due to the surgical trauma are considered responsible for this difference in glucose homeostasis. Splanchnic alanine uptake increased during surgery in both groups, but tended to be somewhat lower in the glucose group. The arterial glycerol concentration and splanchnic uptake, as well as the arterial concentration and splanchnic release of 3-hydroxybutyrate, were reduced. It is concluded that an intravenous infusion of glucose at the rate of 1 mmol/min during abdominal surgery (a) increases the arterial blood glucose level and abolishes splanchnic glucose release, (b) reduces, but does not totally prevent the increase in splanchnic uptake of gluconeogenic substrates, and (c) diminishes lipolysis and the formation of 3-hydroxybutyrate.

Abdomen↗