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Biomedical subjects

I Eriksson

Publications and source records attributed to I Eriksson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Respiratory and cardiovascular effects in relation to plasma levels of midazolam and diazepam.

1. In the present study possible relationships between cardiovascular and respiratory effects and plasma concentrations were investigated after administration of midazolam and diazepam. Eight healthy volunteers were given three injections at 20 min intervals of equipotent sedative doses of midazolam (0.05 mg kg-1) and diazepam (0.15 mg kg-1) in a randomized double-blind cross-over design. Blood pressure, blood-gases and respiration measured nonivasively, were monitored throughout the experimental session of 160 min, and frequent blood samples were collected during the session. 2. Correlations between the blood pressure reduction, the increase of PaCO2 in blood, and plasma concentrations were found for both drugs. A maximal reduction of blood pressure and PaCO2 was produced after sedative doses of midazolam and diazepam. 3. A possible acute tolerance development towards the blood pressure reduction was found after the repeated administration of diazepam but not after the midazolam administration. 4. The plasma concentrations producing half the maximal effects after administration of midazolam was 50-60 ng ml-1, indicating that the influence on blood pressure and PaCO2 after drug administration is evoked at lower plasma concentrations than sedation. 5. No correlation between the respiratory effects and plasma concentrations was found for either drug.

Adult↗
PubMed1988

Surgical reconstruction of incompetent deep vein valves.

Conventional treatment of deep venous insufficiency results in a rather high failure rate. The introduction of methods for surgical repair of incompetent deep vein valves has implied new possibilities for active treatment and has added increased knowledge to venous pathophysiology. This study summarizes our clinical experience with surgical reconstruction of deep vein valves during a nine-year period.

Adult↗
PubMed1987

Tripeptidyl peptidase II in haemolysates and liver homogenates of various species.

Rabbit antibodies against purified tripeptidyl peptidase II (TPP II) of human erythrocytes have been prepared and used in immunoblot analysis. Antibodies affinity-purified against the denatured 135,000-Mr subunit of the human peptidase were shown to cross-react with purified rat liver TPP II, as well as a polypeptide of Mr 135,000 in haemolysates and liver homogenates from several other species. TPP II activity in haemolysates from monkey, hog, horse and rabbit corresponded to the levels found in human erythrocytes, whereas this activity was absent or low in erythrocytes from calf and hen. On immunoblot analysis of the calf haemolysates, the 135,000-Mr polypeptide could not be detected. In contrast, analysis of liver homogenates from these species revealed both TPP activity and immunoreactive polypeptides. Immunoreactive polypeptides with Mr about 105,000 and 84,000 of variable occurrence were also detected. In addition, extracts of Escherichia coli showed no TPP II activity under the conditions of the standard assay, although polypeptides of Mr 135,000 and 40,000 were revealed on immunoblot analysis of this species.

Aminopeptidases↗
PubMed1987

Thrombogenicity of pulmonary-artery catheters.

The thrombogenicity of heparin-bonded and non-heparin-bonded pulmonary-artery catheters was compared by means of pull-out phlebography in a prospective, randomized clinical study of 20 patients in an intensive care unit (ICU). The duration of catheterization averaged 47.4 +/- 4.1 h in the heparin-bonded group (10 patients) and 45.7 +/- 7.1 h in the non-heparin-bonded (10 patients). Age, clinical diagnosis, mean time required to obtain a stable wedge position, heparin dose administered and clotting indices were comparable between the groups. There was no statistically significant difference in the length of formed thrombi (2.3 +/- 1.89 vs 5.88 +/- 4.62 cm) or frequency of thrombus formation between the groups. The thrombi originated and propagated from the puncture site. They were mural proximally and formed sleeves in the superior vena cava. Several sleeves stripped off on withdrawal of the catheter. Protection from thrombosis offered by heparin bonding of pulmonary-artery catheters should, therefore, not be overestimated--at least not in long-term catheterization of ICU patients.

Aged↗
PubMed1987

Effects of repeated doses of benzodiazepines on arterial blood gases and transcutaneous PO2.

The effects of repeated doses of benzodiazepines, diazepam and midazolam in combination with meperidine on arterial blood gases and transcutaneous PO2 were studied in eight healthy volunteers. The study was designed to mimic a clinical situation. Initially two doses of either midazolam 0.05 mg/kg or diazepam in fat emulsion 0.15 mg/kg were given in a randomized crossover fashion with a 20-min interval, followed by meperidine 0.5 mg/kg another 20 min later. The opioid effects were then antagonized by naloxone 0.4 mg. The initial doses of benzodiazepines caused an increase in PaCO2 and a decrease in PaO2. The changes in PaO2 were of short duration and recovered to baseline levels between injections. However, they came sooner and were more pronounced after midazolam. The changes in PtcO2 paralleled those in PaO2. The PtcO2 index as a measure of cardiac output and peripheral blood flow adequacy was increased immediately after the first injection of midazolam but was otherwise not different from control. There were no differences between the drugs concerning PtcO2 index. PaCO2 increased after the first benzodiazepine injection and remained so throughout the study. Addition of meperidine caused only small changes in PaO2 and PaCO2. These changes were reversed by naloxone. In spite of different elimination kinetics there was no difference in the duration of respiratory depression between the two benzodiazepines.

Adult↗
PubMed1987

Changes in breathing pattern and chest wall mechanics after benzodiazepines in combination with meperidine.

The effects of repeated sedative i.v. doses of midazolam and diazepam in combination with meperidine on breathing pattern and thoracoabdominal motion were studied in eight healthy male volunteers. At 20-min intervals in a randomized double-blind crossover design the subjects initially received two doses of midazolam 0.05 mg/kg or diazepam 0.15 mg/kg followed by meperidine 0.5 mg/kg and then naloxone 0.4 mg. Breathing pattern and thoracoabdominal motion were measured non-invasively, utilizing a computerized strain gauge technique. The initial injection of both benzodiazepines caused significant decreases in tidal volume, inspiratory time and expiratory time. There were no significant differences between the two drugs in any of these variables. Minute ventilation, mean inspiratory flow and respiratory timing were not significantly affected. The second injection of both benzodiazepines caused only insignificant additional changes. When meperidine was added, the effects on inspiratory time and tidal volume were small and not significant. However, expiratory time increased and was no longer significantly different from control. The injection of naloxone reversed the meperidine-induced changes only, and the breathing pattern was no longer different from that obtained during benzodiazepines alone. The decrease in tidal volume after the benzodiazepines was almost exclusively mediated by a decrease in the abdominal contribution. Additional doses of benzodiazepines did not enhance these changes. However, meperidine caused a further decrease in the abdominal contribution. This decrease was reversed by naloxone. This indicates that the combination of benzodiazepines and meperidine caused a profound decrease in diaphragmatic performance.

Adult↗
PubMed1987

Changes in respiratory pattern after repeated doses of diazepam and midazolam in healthy subjects.

Changes in respiratory pattern and arterial PCO2 after three repeated intravenous sedative doses of midazolam 0.05 mg/kg or diazepam 0.15 mg/kg were studied in eight healthy male volunteers in a randomized double-blind crossover design. In order to reduce the influence of the measuring equipment, we utilized a noninvasive computerized technique to measure respiratory variables. Both drugs caused equal changes in breathing pattern with a decrease in tidal volume, an increase in respiratory rate and an unaltered minute ventilation. These alterations in breathing pattern were associated with CO2 retention. Respiratory changes were mainly induced by the first injection of either drug. Despite increased plasma drug concentrations, subsequent doses did not cause further changes in respiratory variables except for an increase in PCO2 after the second dose of midazolam. The clinical significance of these changes in PaCO2 in otherwise healthy individuals is probably limited. The duration of the subjective sensation of sedation was longer after diazepam than after midazolam.

Adult↗
PubMed1987

Fibromuscular dysplasia of the renal artery--management and outcome.

Fifty-seven patients (48 women, 9 men) with fibromuscular dysplasia (FMD) of the renal artery were investigated. Mean age at detection of hypertension was 37 years. The diagnosis was established by angiography. Patients with lateralization of renin secretion to the stenotic side had a significantly higher peripheral renin level than those without. The patients were initially treated with surgery (n = 19), percutaneous transluminal renal angioplasty (PTRA) (n = 9), or pharmacologically (n = 29). During a mean follow-up period of 6.2 years, thirteen pharmacologically treated patients were transferred for surgical treatment or PTRA, because of progression of the FMD or inadequate blood pressure control. The long-term effect of surgery (n = 22) on the blood pressure was satisfactory in 91% and that of PTRA (n = 18) in 55%. The low success rate after PTRA seems to be due to an inappropriate selection of patients. Age, duration of hypertension and renal vein renin ratio seem to be important prognostic factors for the outcome of surgery or PTRA.

Adolescent↗
PubMed1986

Small bowel necrosis after aorto-iliac reconstruction.

Small bowel ischaemia causing necrosis is a rare complication after aorto-iliac reconstructive surgery. During a 14-year-period we have seen 6 cases out of 1343 reconstructions, making a frequency of 0.4 per cent. Diagnosis was difficult, causing a delay until re-exploration. Thrombocytopenia was a constant finding, and should raise suspicion. Pathogenesis was multifactorial. In two of our cases diagnosis was made at autopsy and in four at operation. Two patients survived extensive bowel resection but had a long stormy postoperative course.

Adult↗
PubMed1986

Influence of the profunda femoris vein on venous hemodynamics of the limb. Experience from thirty-one deep vein valve reconstructions.

Venous valve reconstruction in 31 limbs (28 patients) with chronic deep venous insufficiency is analyzed. The indications for operation were primary or secondary deep valvular incompetence with severe reflux and venous hypertension. Valvuloplasty was performed on a proximal valve of the superficial femoral vein (SFV) in 17 limbs and on a common femoral vein valve in two limbs; transplantation of a valve-bearing segment of the axillary vein was made to the common femoral vein in two limbs, to the SFV in seven limbs, and to the popliteal vein in three limbs. The results of valvuloplasty were satisfactory, with six failures observed during a follow-up period extending to 84 months (mean, 44 months). Eight of 12 valve transplant reconstructions failed within 2 years. Patency and competence of the reconstruction were obtained in 27 limbs at the 6-month postoperative control period. The effects on venous pressure were analyzed regarding the presence or absence of reflux into the profunda femoral vein (PFV) with preoperative retrograde phlebography. The results showed significant reduction of the ambulatory venous pressure (p less than 0.05) and increase in venous recovery time (p less than 0.01) in limbs with PFV competence. In limbs in which the PFV was incompetent the pressure values remained unchanged. These findings suggest that the functional state of the PFV is of great importance to the venous hemodynamics of the limb. This study also indicates that the principle of one-level repair in the SFV seems appropriate in limbs with a competent PFV.

Adult↗
PubMed1986

CO2 production and breathing pattern during invasive and non-invasive respiratory monitoring.

A computerized non-invasive strain gauge system for respiratory monitoring is described and compared with pneumotachography. With the use of simultaneous capnography, changes in breathing pattern, end-tidal PCO2 and CO2 production were evaluated during non-invasive (NIM) and invasive breathing monitoring (IM) in 14 healthy subjects. An overall absolute difference between measured and calculated tidal volumes of 4.6 +/- 3.47% (r = 0.97) was found. When switching from NIM to IM, tidal volume increased by 19% and breathing frequency decreased by 11% with a 10% increase in minute ventilation. These changes were mainly accomplished by an increased respiratory drive with the timing component unaltered. During IM both end-tidal PCO2 and CO2 production increased significantly as compared with those during NIM.

Adult↗
PubMed1986

Pharmacokinetics of dicloxacillin in serum and aortic wall during aneurysmal surgery.

Twenty-one patients undergoing elective surgery for abdominal aortic aneurysm were randomly assigned to receive 2 grams of dicloxacillin as an intravenous infusion either at the induction of anaesthesia, 3 hours or approximately 6 hours before surgery. Samples from serum and aortic tissue were simultaneously obtained so that antibiotic levels could be compared as a function of time. High concentrations of dicloxacillin in serum and aortic tissue were present already shortly after infusion and active levels were maintained in aortic tissue for approximately six hours. The kinetics of dicloxacillin was similar in serum and aortic tissue. These results support the need for antibiotic administration shortly before surgery to ensure adequate tissue levels of antibiotics.

Aged↗