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Biomedical subjects

T Symreng

Publications and source records attributed to T Symreng.

At least 19 recordsLinked to original sources
PubMed1992

Ventilatory and metabolic changes during high efficiency hemodialysis.

Ventilatory and metabolic changes were measured in seven patients undergoing high efficiency hemodialysis using a cuprophane dialyzer and bicarbonate-containing dialysate. At an HCO3 concentration of 35 mEq/liter and a mean in vivo urea clearance of 3.6 ml/kg/min, hypoxemia was not detected during dialysis (PaO2 was 14.00 and 13.60 kPa before and during dialysis). The new findings, related to high efficiency bicarbonate dialysis, include a sustained rise in minute ventilation (VE, 6.1 to 6.8 liter/min, P less than 0.01), an increase in CO2 excretion (VCO2, 194 to 214 ml/min, P less than 0.05), and O2 consumption (VO2, 215 to 246 ml/min, P less than 0.05). The increment in VE and VCO2 was attributed to the high flux rate of bicarbonate while the rise in VO2 is likely the result of metabolic alkalosis. Arterial pH rose from 7.40 to 7.49 mm Hg and serum HCO3 increased from 23.8 to 29.2 mEq/liter, while pCO2 remained normal at 5.07 kPa throughout the study. The acid-base status of the blood changed from that of a metabolic acidosis to that of a respiratory acidosis across the dialyzer where the pH decreased from 7.47 to 7.41 and pCO2 rose from 5.31 to 7.72 kPa. These data indicate that a healthy ventilatory response is needed to excrete the excess CO2 generated during high efficiency bicarbonate hemodialysis. The significance and etiology of the elevated O2 consumption is undetermined.

Acid-Base Equilibrium↗
PubMed1992

Accuracy of the FEF CO2 detector in the assessment of endotracheal tube placement.

The sensitivity and reliability of the FEF end-tidal CO2 detector were investigated for its suitability in the assessment of correct placement of an endotracheal tube. Sensitivity was determined by having eight blinded volunteers observe the color change in the FEF detector with the administration of different volumes and varying CO2 concentrations of gas mixture. The color change in the FEF detector was also assessed during esophageal ventilations before and after administration of carbonated beverage into the stomach of swine and during cardiopulmonary resuscitation in swine. An interpersonal variation was present among the blinded observers during the color-matching process. Different colors were observed with the same volume and CO2 concentration of gas mixture. During esophageal ventilations before or after the administration of carbonated beverage, the FEF detector was neither accurate nor rapid in identifying esophageal placement of the endotracheal tube. The "C" color was displayed during the initial six ventilations in one swine, and esophageal intubation would have been missed. The FEF detector could (by displaying a "C" color) identify one of six correctly intubated swine during cardiopulmonary resuscitation. In conclusion, the FEF CO2 detector does not have the characteristics to reliably assess the correct placement of an endotracheal tube.

Animals↗
PubMed1992

Effect of music therapy in the postanesthesia care unit: a nursing intervention.

This study examined the effect of music on pain, hemodynamic variables, and respiration in the PACU, and the impact of music on patients' recall of their PACU experience. Sixty patients scheduled for thyroid, parathyroid, or breast surgery under general anesthesia were studied. Patients were randomly assigned into three groups: group 1, control, not wearing headphones; group 2, wearing headphones but hearing no music; and group 3, wearing headphones and listening to music. A visual analogue pain scale was used to rate patients' perception of pain. There was no difference in pain level, morphine requirement, hemodynamics, respiration, or length of stay in the PACU among the 3 groups, yet the music group was able to wait significantly longer before requiring analgesia on the nursing unit. Patients who listened to music perceived their PACU experience as significantly more pleasant than the patients in the other two groups as recalled both 1 day and 1 month later.

Adult↗
PubMed1991

Stable and reproducible porcine model of acute lung injury induced by oleic acid.

BACKGROUND AND METHODS: Previous studies on acute lung injury induced with oleic acid did not attempt to limit the influence of secondary changes on pulmonary circulation, and cardiopulmonary variable data were only collected and processed intermittently. Our study was designed to continuously monitor the following variables in five swine: systemic and pulmonary pressure; mixed venous oxygen saturation (SVO2) and arterial oxygen saturation (SaO2); minute oxygen consumption and CO2 production before, during, and for 4 hr after the infusion of oleic acid. A personal computer was programmed to produce 20-sec updates of deadspace ratio (VD/VT), venous admixture (Qsp/Qt), pulmonary (PVR) and systemic vascular resistance (SVR), and cardiac output (Qt) from these data. RESULTS: During the oleic acid infusion, there were increases in PVR, SVR, heart rate (HR), mean pulmonary arterial pressure (MPAP), Qsp/Qt, and VD/VT, and a decrease in Qt, SaO2, and SVO2. Thirty minutes after the oleic acid infusion, there was a further increase in HR, Qsp/Qt, and VD/VT, while MPAP, PVR, and SVR gradually decreased to pre-oleic acid infusion levels. No further decrease in SaO2, SVO2, and Qt was observed during that time. After the 30-min period, there was no further change in the cardiopulmonary variables. CONCLUSION: Our method of continuous monitoring was able to demonstrate in swine both the dynamic changes during, and stability after, the oleic acid infusion.

Animals↗
PubMed1991

Reliability of capnography in identifying esophageal intubation with carbonated beverage or antacid in the stomach.

To evaluate the reliability of capnography in identifying esophageal intubation in the presence of a carbonated beverage in the stomach, we first investigated the amount of CO2 released from different carbonated beverages and antacids in a simulated stomach; next we measured the end-expired CO2 level during esophageal ventilation with a carbonated beverage in the stomachs of six swine. CO2 levels of approximately 20% were consistently observed in all carbonated beverages. The CO2 levels obtained with sodium bicarbonate, Maalox, and sodium citrate were 19.3%, 2.0%, and 0%, respectively. CO2 waveforms were observed during esophageal ventilation in five of six animals after intragastric administration of a carbonated beverage. An end-expired CO2 level of 2.5% or more was observed in two swine. The highest end-expired CO2 level measured was 5.3%. We conclude that although capnography is convenient and effective, it lacks all the attributes of an ideal monitor for detecting esophageal intubation.

Animals↗
PubMed1990

Limited lateral thoracotomy. Improved postoperative pulmonary function.

A prospective randomized controlled study was designed to determine differences in early postoperative pulmonary function, pain, and complications between patients undergoing limited lateral muscle-sparing thoracotomy. Fifteen patients underwent standard thoracotomy and 13 underwent limited incision with the same anesthetic technique. During the first 24 hours after operation, there were large decreases in the results of spirometric tests of pulmonary reserve (forced expiratory volume in 1 second and forced vital capacity), but these decrements were consistently significantly smaller in the limited-incision group. Other tests of pulmonary function (mid-expiratory phase forced expiratory flow, alveolar-arterial oxygen gradient, and PaCO2), however, demonstrated similar postoperative changes in both groups. Similarly, there were no differences in pain scores, postoperative morphine requirements, complications, or length of hospital stay. Use of the limited muscle-sparing incision resulted in improved postoperative pulmonary reserve, but this did not translate into differences in other measures of postoperative convalescence.

Female↗
PubMed1990

Inconsistent esophageal Doppler cardiac output during acute blood loss.

Application of the Doppler principle can provide relatively noninvasive and continuous measurement of cardiac output. However, it is based on certain assumptions that may introduce error. Esophageal Doppler cardiac output was compared with Fick cardiac output during acute blood loss (35-45% estimated blood volume) in eight anesthetized pigs. Mean Fick cardiac output decreased from 4.8 to 1.9 l/min, mean Doppler cardiac output from 4.9 to 2.9 l/min. This was accompanied by a decrease in mean arterial pressure from 119 to 55 mmHg and increase in heart rate from a mean of 115 to 156 beats/min. There was an inconsistent association between the two methods both within and between individual animals. Cubic polynomial regression equations of cardiac output with time indicated small measurement error in Fick (R2: mean 0.93, range 0.99-0.75) as opposed to Doppler (R2: mean 0.67, range 0.93-0.16) cardiac output. In one animal Doppler cardiac output showed an increase with time and in one the Doppler cardiac output measurements were unrelated to time. There was highly variable association comparing Fick versus Doppler cardiac output with correlations ranging from -0.76 to 0.98. A sign test for mean differences indicated that Doppler derived cardiac output was higher than Fick cardiac output, and the chance of this occurring if the true difference was zero was less than 1 in 1,000. A test for homogeneity of correlations was also rejected. Inaccuracies in individual assumptions in the computation of esophageal Doppler cardiac output, especially unaccounted changes in aortic diameter, are responsible for the inconsistent and unpredictable values of Doppler cardiac output obtained in this experimental model of hemorrhage.

Acute Disease↗
PubMed1990

Reduced venous admixture in hemorrhagic hypovolemia: maintenance of arterial oxygenation by selective pulmonary vascular collapse.

In nine anesthetized and ventilated swine, a microcomputer calculated cardiac output, venous admixture (Qsp/Qt) and physiologic deadspace (VD/VT) every 20 sec, utilizing dual oximetry and a gas exchange analyzer. After lung injury with ethchlorvynol (ECV), animals were bled 40% blood volume over 40 min. Mean cardiac output decreased 7.0 to 2.2 L/min (p less than .05) accompanied by a decrease in mean Qsp/Qt from 0.28 to 0.14 (p less than .05) and an increase in mean VD/VT from 0.39 to 0.54 (p less than .05). Arterial Hgb saturation (Sao2) increased from 88 +/- 7% to 90 +/- 6%. On regression of all data points for each variable, Qsp/Qt had a positive correlation with cardiac output (r = .90), mean arterial pressure (MAP, r = .87), mean pulmonary artery pressure (MPAP, r = .86), and mixed venous Hgb saturation (Svo2, r = .89, p less than .001). VD/VT had an inverse correlation with cardiac output (r = -.90), MAP (r = -.82), Qsp/Qt (r = -.83), MPAP (r = -.77), and Svo2 (r = -.92, p less than .001). The decreasing Qsp/Qt and increasing VD/VT, with decreasing pulmonary perfusion pressures, were attributed to selective loss of perfusion to alveoli with low ventilation/perfusion ratios.

Animals↗
PubMed1990

Continuous, in vivo pulmonary venous admixture from fiberoptically measured hemoglobin saturations.

In six anesthetized swine, pulmonary venous admixture (Qsp/Qt) was calculated by four methods: a) Qsp/Qt 1, fiberoptically measured arterial and mixed venous Hgb saturation (SaO2 and SvO2), PaO2 and PvO2 derived from saturations; b) Qsp/Qt 2, fiberoptically measured SaO2 and SvO2, PaO2 and PvO2 measured by blood gas analysis; c) Qsp/Qt 3, PaO2 and PvO2 measured by blood gas analysis, SaO2 and SvO2 derived from tensions; d) Qsp/Qt 4, SaO2 and SvO2 measured by bench oximetry, PaO2 and PvO2 derived from saturations. Input from the fiberoptic catheters was fed into a computer programmed to calculate Qsp/Qt 1 every 20 sec. Fifty-eight of these values were compared with simultaneously calculated Qsp/Qt 2, 3, and 4. There was no difference between fiberoptic and derived SaO2 or fiberoptic and cooximetric SvO2. Correlations and slopes for Qsp/Qt 1 with Qsp/Qt 2, 3, and 4 were significant (p less than .05). Comparing mean differences, Qsp/Qt 1 was significantly different only from Qsp/Qt 3 (p less than .01). We conclude that dual oximetry reliably tracks Qsp/Qt.

Animals↗
PubMed1990

Prevalence of protein-energy malnutrition in a large population of elderly people at home.

The prevalence of protein-energy malnutrition (PEM) was examined in 1206 randomly selected elderly people aged 65 to 80 years living in their own homes. Nutritional assessment was based on weight loss, weight index, triceps skin fold, arm muscle circumference, serum albumin and prealbumin, and delayed cutaneous hypersensitivity (DCH) reaction. The prevalence of PEM was 5 per cent. If people with signs of inflammation were excluded, the prevalence of PEM was 3.5 per cent. When other nutritional indices, used by other authors among hospitalized patients, were applied to our sample prevalence values from 2.6 to 4.1 per cent were obtained. the prevalence was not related to sex or age. DCH increased the sensitivity of the screening method but causes of anergy other than PEM must be taken into account. It is concluded that PEM, in a degree shown to impair the prognosis at hospital, does occur among elderly people at home in an industrialized country.

Aged↗
PubMed1989

Intrapleural bupivacaine--technical considerations and intraoperative use.

The authors evaluated the incidence and type of technical problems associated with blind insertion of intrapleural catheters placed in 21 anesthetized patients and then injected in a double-blind fashion with 0.5% bupivacaine (1.5 mg/kg) or isotonic saline. The patients' chests were then opened, catheter positions located, and the lungs inspected. Eleven of the catheters were located with the tips intrapleurally, three extrapleurally, and seven actually in lung tissue. Eight patients had holes in the lung surface. Three patients had a pneumothorax, two of which were under tension. Plasma bupivacaine levels reached maximal concentrations at about 20 minutes in those with intrapleurally placed catheters, but not until 60 minutes when the catheter had actually penetrated the lung. Significant variations in plasma bupivacaine levels were achieved when the catheter entered lung tissue, with potentially toxic levels in one patient. To evaluate intraoperative analgesic effects, all patients were given a standard anesthetic with isoflurane, oxygen, and a muscle relaxant. There was no significant difference in isoflurane requirement between the groups who had bupivacaine v saline injected into their intrapleural catheters before surgery. It is concluded that blind insertion of intrapleural catheters can be hazardous, especially if followed by positive-pressure ventilation. In addition, catheter placement in lung tissue, which was not uncommon, delays the time for peak plasma concentrations and may increase risk of toxicity. Intrapleural bupivacaine was not found to be a useful adjunct to general anesthesia during thoracotomies.

Adult↗
PubMed1989

Intrapleural bupivacaine v saline after thoracotomy--effects on pain and lung function--a double-blind study.

The effects of intrapleural (IP) bupivacaine on pain, morphine requirement, and pulmonary function were evaluated in 15 patients for 24 hours after thoracotomy. An IP catheter was placed during surgery. Patients were randomized in a double-blind fashion to receive 1.5 mg/kg of 0.5% bupivacaine IP or saline on two occasions, eight hours apart. A standard anesthetic with thiopental, oxygen, isoflurane, and nondepolarizing muscle relaxant was given. Pain was evaluated with a visual analog pain score every hour, and forced vital capacity (FVC), forced expiratory volume one second (FEV1), peak expiratory flow (PF), and forced expiratory flow 25% to 75% (FEF) were measured 1, 2, 4, 8, and 24 hours postoperatively as well as before and 30 minutes after each IP injection. Arterial blood gases were sampled 1, 2, 8, and 24 hours postoperatively. Plasma bupivacaine concentrations were measured in 10 patients 5, 10, 20, 30, 60, 120, and 180 minutes after IP injection. With each IP bupivacaine injection, the pain score and morphine requirement decreased. There was a significant improvement in all pulmonary function tests in the patients receiving bupivacaine, but no change in the saline controls. The analgesic effect was shortlived (two to five hours), possibly because of loss of bupivacaine in the chest drains. No differences were seen between the two groups after the effect of IP bupivacaine had worn off. Plasma bupivacaine levels had a Cmax of 0.44 to 1.50 micrograms/mL, with a Tmax at 5 to 30 minutes with levels well below 2 to 4 micrograms/mL where increasing toxicity is seen.

Aged↗
PubMed1988

Measurement of right atrial oxygen saturation by fiberoptic oximetry accurately reflects mixed venous oxygen saturation in swine.

Continuous fiberoptic measurement of mixed venous oxygen saturation (SvO2) via a pulmonary artery catheter is a useful, though invasive, monitoring technique. Continuous right atrial venous oxygen saturation measurement by oximetry offers the potential of a significantly less invasive SvO2 measurement. However, catheter motion, character of the vessel, chamber wall reflection, the filtering technique involved in calculating oxygen saturation, and the streaming of venous blood prior to ventricular mixing may influence the feasibility of continuous right atrial (RA) SvO2 measurement. This study investigated the performance of fiberoptically measured RA SvO2, at a position 2 cm from the tricuspid valve, relative to simultaneously measured pulmonary artery (PA) SvO2. Ten pigs were subjected to circulatory shock or chemically induced lung damage. Over a total monitoring period of approximately 40 hours, 464 paired data points were sampled at 5-minute intervals. The difference between the overall means of RA and PA SvO2 was 0.91% with a standard error of the estimate of 4.7%, a regression equation of RA SvO2 = PA SvO2 (0.94 + 2.1) PA So2, and a correlation coefficient of 0.94. Our conclusion, although extrapolated from a pig model, is that fiberoptic SvO2 monitoring may be accomplished less invasively and at a lower cost with a right atrial catheter.

Animals↗
PubMed1985

The effect of pre-operative total parenteral nutrition on energy-rich phosphates, electrolytes and free amino acids in skeletal muscle of malnourished patients with gastric carcinoma.

The effect of two weeks of total parenteral nutrition (TPN) on energy-rich phosphates, muscle water, electrolytes and free amino acids in skeletal muscle were determined in ten malnourished patients with gastric carcinoma. The total adenine nucleotide pool, phosphocreatine, creatine and glycogen were decreased before TPN, and only glycogen returned to normal after TPN compared with controls. Total muscle water and the intramuscular concentrations of sodium and chloride were initially increased and were not influenced by TPN. The total non-essential amino acids in muscle were decreased by 9 per cent, mainly due to a 15 per cent decrease in glutamine. The concentrations of free amino acids in muscle were not affected by two weeks of TPN. This study demonstrates disturbances in energy, water and amino acid metabolism in skeletal muscle of malnourished patients with gastric carcinoma, and that two weeks of TPN could not normalize these changes, except in the case of glycogen. The reason for this might be enzyme abnormalities due to adaptation to energy or protein deficit. A longer period of refeeding might therefore be necessary to improve peripheral metabolism in these patients.

Aged↗
PubMed1985

Muscle water and electrolytes in relation to nutritional status in gastric carcinoma.

Muscle water and electrolytes were studied preoperatively in 22 patients with gastric carcinoma. Compared to controls, extracellular water and hence total muscle water was increased, but intracellular water was normal. Muscle sodium and chloride levels were increased in these patients while potassium and magnesium levels were normal. Based on nutritional assessment the patients were divided into wellnourished (group I, n = 7) with no or minor signs of malnutrition and malnourished (group II, n = 15) with signs of pronounced malnutrition. The wellnourished patients had normal content of muscle water and electrolytes, while in the malnourished an increase in total water, sodium and chloride in muscle tissue was found. The difference between the two groups, could be explained by malnutrition alone, since tumour size, histology, metastatic spread and operability did not differ between the two groups. A negative correlation was found between total water and both albumin and creatinine-height index which further indicates a close relationship between nutritional status and muscle water and electrolytes. In addition these findings revive the interest in nutritional assessment as a simple way of identifying metabolically deranged patients.

Journal Article↗
PubMed1985

Changes in muscle and plasma amino acid metabolism in severe malnutrition--the influence of total parenteral nutrition.

The concentrations of free amino acids in muscle and plasma were determined in nine female patients with severe anorexia nervosa before and after 3 to 5 weeks of total parenteral nutrition (TPN). The patients had lost 25 to 42% of their pre-morbid weight. During TPN their weight gain was around 2.5 kg/week. Initially total non-essential amino acids (NEAA) in muscle were decreased 30% compared to controls. The major part of this depletion was due to a 40% reduction in glutamine. After TPN the level of glutamine normalized. Alanine, being normal before TPN, decreased after TPN. Proline and several other non-essential amino acids in muscle were decreased before and after TPN. Total essential amino acids (EAA) in muscle were initially normal and were not significantly affected by TPN. Total NEAA in plasma were decreased at admission and normalized after TPN. Total EAA in plasma, however, were normal both before and after TPN. This study demonstrates that severely malnourished patients with anorexia nervosa have changes in amino acid patterns in both muscle and plasma. These changes were largely, though not completely, reversed after 3 to 5 weeks of TPN.

Journal Article↗
PubMed1985

Changes in nutritional assessment variables caused by total parenteral nutrition in anorexia nervosa.

Nutritional assessment variables were measured weekly in 10 young women with severe anorexia nervosa during treatment with total parenteral nutrition (TPN) for a 5 week period. Before the start of treatment the patients had lost 25-53% of their habitual weight, triceps skin fold (TSF) and arm muscle circumference (AMC) measurements were below the 5th percentile and all were anergic in the delayed hypersensitivity (DH) response. Plasma protein levels were normal except in fibronectin and prealbumin where levels below the reference interval was found in five patients. During TPN the body weight increased most likely due to rehydration and increase in lean body mass. Significant increases were seen in body weight weekly, but in TSF and AMC only after 4 and 3 weeks respectively. TSF and AMC were still below or at the 5th percentile after 5 weeks of TPN. DH response as well as fibronectin and prealbumin levels normalised in all patients. Despite only partial recovery in body cell mass the clinical picture had changed markedly so that the patients now were amenable to psychotherapy and had an adequate intake of food orally, enabling further nutritional therapy to be completed without parenteral support.

Journal Article↗