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Biomedical subjects

B Gustavsson

Publications and source records attributed to B Gustavsson.

At least 91 records · Page 5Linked to original sources
PubMed1983

Stiffness of central venous catheters.

Catheter stiffness has been suggested to be a principal factor in the thrombogenesis encountered after central venous cannulation. However, no data have been published to date about the stiffness of central venous catheters. A method for measuring catheter stiffness has been developed. The force needed to deflect a catheter tip 1.2 mm from a fastening point was measured with the help of a cantilever beam (Grass Model DA-7). Six different sections of each catheter were measured, and the final results expressed as an average of these. Twenty-seven central venous catheters made of silicone elastomer, polyurethane, polyvinylchloride, polyethylene and teflon were tested. The bending stiffness, EI (E = elastic modulus of the material, I = moment of inertia of catheter (a geometrical property)) was below 16 X 10(-6) Nm2 for all catheters made of silicone elastomer, polyvinylchloride and polyurethane. Polyethylene catheters were stiffer, but could be made softer by reduction of their diameters. Teflon catheters were up to 10 times stiffer than the catheters in the soft group. Heparinization and radioopacity of catheters do not significantly alter their bending stiffness. In a concomitant study the results indicate that there is a significantly lower incidence of thrombus formation in catheters with a bending stiffness below 16 X 10(-6) Nm2.

Catheterization↗
PubMed1983

Material thrombogenicity in central venous catheterization II. A comparison between plain silicone elastomer, and plain polyethylene, long, antebrachial catheters.

Central venous catheters of two types were inserted through basilic or cephalic veins punctured at the fossa cubiti in 61 patients: 39 soft silicone elastomer (S.E.) and 22 stiffer polyethylene (P.E.) catheters were compared regarding their thrombogenicity. Mean duration of catheterization was 6.5 days. Radiological thrombi in the peripheral and central veins visualized by phlebography were significantly smaller, and the incidence of the mural thrombi in the central veins significantly lower with the S.E. than with the P.E.-catheters, but the use of S.E.-catheters did not reduce the incidence of clinical thrombophlebitis in arm veins: 14 cases in the group with S.E. and four in that with P.E.-catheters. In both groups, the maximum incidence of clinical thrombophlebitis occurred 4-8 days after catheterization. Later, there seems to be a low risk for the appearance of clinical thrombophlebitis with both catheters. Neither the surface topography of the catheter materials, nor the platelet adhesion on their surfaces in contact with human blood in vitro offered conclusive arguments for interpretation of their thrombogenicity in vivo. Catheter stiffness seems to play an important role in inducing mural thrombus formation in central venous cannulation in man.

Adolescent↗
PubMed1983

Portal blood flow in man during surgery, measured by a modification of the continuous thermodilution method.

The continuous thermodilution method was applied to measurement of peroperative portal venous blood flow in man in relation to hepatic surgery during steady-state enflurane nitrous oxide anaesthesia. Portal-vein catheterization through the umbilical vein for cytostatic administration and blood flow measurements was successful in 14 out of 17 patients with primary or secondary liver tumours. Mean portal blood flow was 1195 +/- 179 ml X min-1 (mean +/- SEM), corresponding to 17.6 +/- 2.9 ml X min-1 X kg-1 body weight. Mean oxygen consumption in the prehepatic splanchnic area was 0.27 +/- 0.04 ml X min-1 X kg-1. No significant complications were associated with the catheterization or flow recording procedures. The described method offers possibilities for haemodynamic and pharmacokinetic investigations in man.

Catheterization↗
PubMed1983

Hepatic artery occlusion for liver cancer.

The survival of patients with tumour growth in the liver is very restricted. Interruption of the arterial blood supply to the liver is one method used to control tumour growth. This method is based on the findings that liver tumours are mainly nourished by the hepatic artery. Different methods are used in order to interrupt the arterial blood supply to the liver. Hepatic artery ligation (HAL) has been found in animal experiments to be the most reproducible method to temporary retard tumour growth. Survival has been shown to be prolonged in animals with liver tumours subjected to HAL compared with untreated controls. In humans no effect on the survival time has been observed, but the quality of life of these patients has been claimed to be improved especially those with the carcinoid syndrome. Although interruption of the hepatic arterial blood supply has been used clinically for more than 15 years the method is still an experimental procedure. Further clinical research in this field requires properly designed randomized studies.

Adenocarcinoma↗
PubMed1982

Effect of polyethyleneglycol (PEG) on spontaneous and polymyxin B-induced histamine release from rat peritoneal mast cells.

Mast cells were isolated from the peritoneal cavity of rat and purified by centrifugation in a gradient of Percoll. The spontaneous and polymyxin B-induced release of histamine was studied after preincubation of the cells with polyethyleneglycols (PEGs) of different molecular weight (200-20,000 dalton) and with fatty acid derivatives of PEG 6000. It was found that very low concentrations (less than 0.1%) of PEG 6000 reduced the spontaneous and polymyxin B-induced release of histamine to a greater extent than the same concentration of bovine serum albumin. The inhibition increased with the size of the PEGs, but was little affected by the presence of fatty acid ligand bound to PEG.

Animals↗
PubMed1982

Oral administration of 5-fluorouracil: renal clearance and urinary concentration in man.

The pharmacokinetics of 5-fluouracil were studied in 9 patients with a history of bladder malignancies. A single dose of 250 mg. 5-fluorouracil was given orally and the renal clearance of active 5-fluorouracil was approximately 40 ml. per minute. The maximum serum (1,100 ng./ml. serum) and urinary concentrations (49,000 ng./ml. urine) of 5-fluorouracil occurred 20 and 40 minutes after administration, respectively. The urinary concentration per se is highly cytotoxic, whereas the short-lasting serum concentration previously has been proved to be without general cytotoxic effects even after continuous use of the drug for years. Although high concentrations of 5-fluorouracil are noted in the urine the antitumor effects of this treatment must be investigated further.

Administration, Oral↗
PubMed1982

Material thrombogenicity in central venous catheterization. I. A comparison between uncoated and heparin-coated, long antebrachial, polyethylene catheters.

In order to evaluate a new method of heparinization, uncoated (22) and heparin-coated (27) central venous polyethylene catheters were inserted in 49 patients via basilic and cephalic veins punctured at the fossa cubiti. The means duration of catheterization was 5.7 (1-11) days. One-third of the patients with heparin-coated catheters, and one sixth with uncoated catheters developed clinical thrombophlebitis, with a maximum incidence between 4 and 8 days after catheterization. A higher risk of developing thrombophlebitis in the first 4 days after catheterization was found in the patients with heparin-coated polyethylene catheters. After 8 days of catheterization, it seems that there is a lower risk of new cases of thrombophlebitis appearing both in patients with uncoated and those with heparin-coated polyethylene catheters. Radiological thrombosis, regardless of duration of catheterization and heparin-coating, was demonstrated in all 22 patients investigated by "pull-out" phlebography. The heparin-coating did not decrease the rate of thrombotic complications. Location of the catheter tip in subclavian veins was associated with a significantly higher incidence of large, parietal thrombi and catheter occlusion than when the tip was situated in anonymous veins, the superior vena cava, or the right atrium. Cannulation by heparin-coated, polyethylene tubing did not reduce the rate of catheter occlusion.

Adolescent↗
PubMed1982

Effects of halothane on coronary haemodynamics and myocardial metabolism in patients with ischaemic heart disease and heart failure.

Halothane was administered at an end-tidal concentration of 1% to 10 patients with stable ischaemic heart disease and clinical and haemodymanic signs of moderate heart failure. Measurements of central haemodynamic variables, coronary sinus blood flow and oxygen, lactate and hypoxanthine balances over the myocardium were done before and at steady state during halothane anaesthesia. Halothane induced marked haemodynamic changes with decreases in mean arterial pressure (-43%), mean pulmonary arteriolar occlusion pressure (-42%), systemic vascular resistance (-31%), cardiac index (-20%) stoke volume index (-31%) and left and right stroke work indices (-62% and -55%, respectively). Heart rate and pulmonary vascular resistance did not change. Coronary sinus blood flow decreased in parallel with perfusion pressure, and myocardial oxygen consumption decreased (-40%), as did myocardial oxygen extraction. Rate pressure product and triple product correlated better with changes in myocardial oxygen consumption in the present subset of patients than in healthy volunteers during halothane anaesthesia. The findings suggest that halothane, through its systemic vasodilatory effect, unloads the failing left ventricle and that this peripheral action predominates over the direct cardiodepressant action of the agent. The combined findings of unchanged coronary vascular resistance, decreased myocardial oxygen extraction and absence of increasing or pathological levels of lactate and hypoxanthine in coronary sinus blood imply a direct dilatory effect of halothane on the coronary vasculature.

Aged↗
PubMed1982

The continuous thermodilution method for measuring high blood flows.

The continuous thermodilution method for the measurement of blood flow from 300 to 1500 ml/min was evaluated in vitro and in vivo. In vitro experiments indicated that thermotransport within the catheter, causing a temperature measurement error, can occur. Flow model measurements were used for consequent modification of the original thermodilution formula for calculation of flow. In the in vivo investigations the thermodilution and electromagnetic methods were compared for measurement of pig portal blood flow. Using the modified formula for the flow calculations, good agreement was found between the two methods (r = 0.958). For the continuous thermodilution method in vivo the standard deviation of a single measurement was 19 ml/min and the coefficient of variation 1.6%.

Animals↗
PubMed1982

Percutaneous drainage of intraabdominal fluid collections.

Nine cases of percutaneous drainage of intraabdominal fluid collections in eight patients are reported. Ultrasonography and conventional radiography was utilized to make the diagnosis and to plan and perform puncture and drainage. In one case of subhepatic abscess only punction and aspiration was performed. In all other cases draining catheters were left between 3 and 21 days. Except in one case which later proved to be a cystic adenopapillary carcinoma of the kidney the results were good.

Adult↗
PubMed1981

Trauma to the liver during a ten-year period. With special reference to morbidity and mortality after blunt trauma and stab wounds.

The records of 58 patients with hepatic injuries treated between 1969 and 1978 were analyzed in retrospect. The hepatic injury was caused by blunt trauma in 30 cases (52%), stab wounds in 26 cases (45%) and gun shot wounds (GSW) in 2 cases (3%). In 45 patients (78%) the injury could be managed by simple methods such as laparotomy alone or suture and/or drainage. Hepatic lobectomy was performed in 5 patients (9%). When compared with stab wounds, hepatic injuries after blunt trauma were associated with higher frequency of shock, more blood transfusions, more associated injuries, more severe liver injuries and longer hospital stay. Overall mortality rate was 19%. True hepatic injury mortality rate was 5%. After blunt trauma mortality rate was 30% and after stab wounds 4%. The mortality rate was higher in patients with multiple associated injuries and after more severe hepatic injuries.

Adolescent↗
PubMed1980

Displacement of catheters inserted through internal jugular veins with neck flexion and extension. A preliminary study.

Displacement of central venous catheters inserted through internal jugular veins in adult man was estimated on chest x-rays in six patients and measured in six corpses. The downward displacement of the catheter tips with maximum neck flexion varied between 1.0 and 2.0 cm in patients, and between 1.0 and 2.5 cm in corpses. The upward displacement with maximum neck extension varied between 0.5 to 1.0 cm in patients and 0.5 to 1.5 cm in corpses. The total displacement varied between 1.5 to 3.0 cm in patients, and 1.5 to 4.0 cm in corpses. The geater displacement in corpses might be explained by detachment of sternocleidomastoid muscles, and by resection of the sternum and anterior ribs, performed for access to the heart and superior vena cava. There was no apparent correlation between the side and site of the vein puncture, body length, sternocleidomastoid length, distances from the punction sites to suprasternal notch, and values of the displacements of the catheter tips in any group. To avoid rhythm disturbances and perforation of the heart (possible complications of the catheter displacement), the necessity of locating central venous catheter tips 3.0 to 4.0 cm above the superior vena cava-right atrial junction, and firm fixation of the catheter is stressed.

Adult↗