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Biomedical subjects

F Colardyn

Publications and source records attributed to F Colardyn.

At least 73 records · Page 4Linked to original sources
PubMed1993

Sorption of isosorbide dinitrate to central venous catheters.

As several studies demonstrated the sorption of isosorbide dinitrate (ISDN) to intravenous delivery systems, a study on the sorption of ISDN to several central venous catheters was performed. Fourteen different catheters were perfused during a 2 h period, under simulated infusion conditions, with ISDN (250 micrograms mL-1) in 0.9% (w/v) sodium chloride. The drug loss to a polyethylene and a silicone catheter was 0.2 and 6.1%, respectively. The sorption to a polyvinylchloride heparin-coated thermodilution catheter was 1-6.9% depending on the length of the catheter. The drug loss to polyurethane catheters of different composition varied between 3.8 and 28.9%. For polyurethane catheters composed of cycloaliphatic polyurethanes an inverse relation was shown between Shore A hardness and sorption.

Adsorption↗
PubMed1993

Light stability of molsidomine in infusion fluids.

The influence of artificial light, daylight or stimulated sunlight on the stability of molsidomine was investigated. In static experiments an 80 micrograms mL-1 solution of molsidomine in saline was stored in an unprotected infusion bag. During dynamic experiments the molsidomine solution (80 micrograms mL-1) was dropped at 12.5 mL h-1 from an unprotected infusion bag, from an infusion bag covered with aluminium-foil, or from an infusion bag protected with a UV-cover. Either unprotected infusion tubing or infusion tubing with a UV-filter were connected to the infusion bags. Static as well as dynamic experiments showed a half-life of about 20 min for the unprotected molsidomine solutions, when placed behind a window during a sunny day. Protection from light of the infusion bag but not of the infusion tubing had only a minor influence on the drug half-life. Protection of the infusion bag and the infusion tubing with a UV-filter increased the half-life to several days. These results confirm that both the infusion bag and the infusion tubing need adequate light protection during molsidomine administration.

Chemistry, Pharmaceutical↗
PubMed1993

Delivering critical care: a challenge.

Because of the need for rapid diagnosis and management of patients acutely stricken by either injury or illness, critical care delivery cannot be limited to intensive care units. Instead, it must span the continuum from the scene of injury or illness to the patient's eventual arrival at the intensive care unit. University Hospital in Ghent, Belgium, has developed a comprehensive system that involves prehospital and in-hospital critical care, as well as a rapid and efficient interhospital and intrahospital transportation system. The prehospital system consists of a mobile intensive care ambulance, rapid-response systems known as flying squads, and a rendezvous system coordinating the ambulances and the rapid-response systems. The flying squad is staffed by a physician and the ambulance by a physician or a medical student in the last year of study. Both are also manned by an emergency department nurse and a professional driver who is also an emergency medical technician. The emergency department and its staff are available 24 hours a day to ensure uninterrupted delivery of critical care, including when patients are transported between various hospital departments. In addition, critical care specialists with at least 2 years' intensive care experience are available 24 hours a day. They also serve as coordinators for disaster planning for the hospital and the city of Ghent and its province.

Belgium↗
PubMed1992

Plasma concentrations of pralidoxime methylsulphate in organophosphorus poisoned patients.

Using pharmacokinetic data from healthy human volunteers in a bicompartmental pharmacokinetic model, a repeated dose scheme for pralidoxime methylsulphate (Contrathion) was developed producing plasma levels remaining above the assumed "therapeutic concentration" of 4 mg.l-1. Using the same data, it was found that a concentration of 4 mg.l-1 could also be obtained by a loading dose of 4.42 mg.kg-1 followed by a maintenance dose of 2.14 mg.kg-1.h-1. In order to study the pharmacokinetic behaviour of pralidoxime in poisoned patients, this continuous infusion scheme was then applied in nine cases of organophosphorus poisoning (agents: ethyl parathion, ethyl and methyl parathion, dimethoate and bromophos), and the pralidoxime plasma levels were determined. The mean plasma levels obtained in the various patients varied between 2.12 and 9 mg.l-1. Pharmacokinetic data were calculated, giving a total body clearance of 0.57 +/- 0.27 l.kg-1.h-1 (mean +/- SD), an elimination half-life of 3.44 +/- 0.90 h, and a volume of distribution of 2.77 +/- 1.45 l.kg-1.

Dose-Response Relationship, Drug↗
PubMed1992

Hazardous information from bedside fast-flush device test for fluid-filled pressure monitoring systems.

The fast-flush device test--based on the square-wave principle--has been used in clinical practice to test the accuracy of fluid-filled pressure-monitoring systems. One assumption with the square-wave test is that the system is a second-order approximation. To elucidate the problem, the authors compared, in vitro, a reference test method (frequency response test), valid for second-order systems, with a pure square-wave test and a fast-flush device test. They showed that the two tested systems did not have any relation to the reference system, which suggests that the second-order approximation is not valid. Therefore, the fast-flush device test cannot be used reliably in testing the total chain of catheter, tubing, transducer, and monitor for invasive pressure measurement.

Blood Pressure Determination↗
PubMed1991

Postsynaptic neuromuscular dysfunction in organophosphate induced intermediate syndrome.

A 65-year-old Caucasian female developed an intermediate syndrome seven days after an acute cholinergic crisis, caused by the ingestion of fenthion. Cholinesterase activity in the blood, plasma and red cells was monitored daily by the method according to Nenner and serial serum fenthion levels were measured by capillary gas chromatography. Electromyographic studies showed fade on tetanic stimulation by means of surface electrodes at 20 Hz of the left M. abductor digiti quinti at day 7, which could no longer be observed at day 19. Fade on low-frequency stimulation and post-tetanic facilitation were both absent. A biopsy of the N. suralis was normal. A biopsy of the M. tibialis anterior revealed a limited rhabdomyolysis with a very weak staining for cholinesterase. It is hypothesized that the pathophysiologic process underlying the syndrome is the result of a time-confined phenomenon, which includes both changes in the postsynaptic structures by a desensitization process and a gradually restoring ratio of acetylcholine to acetylcholinesterase. This hypothesis is suggested by the similarity in the EMG-findings of this patient and those in myasthenia gravis, which is known to be characterized by a postsynaptic transmission defect.

Acetylcholinesterase↗
PubMed1991

Influence of intravenous administration set composition on the sorption of isosorbide dinitrate.

The influence of the composition of administration sets on the sorption of isosorbide dinitrate was investigated in-vitro. Isosorbide dinitrate solutions (250 micrograms mL-1) in 0.9% NaCl or 10% glucose were stored in glass containers and administered at a flow rate of 20 mL h-1. The influence of the concentration of different plasticizers (di-ethylhexylphthalate, tri-ethylhexyltrimelitate) in polyvinylchloride tubings was determined. Polybutadiene tubings of different mol. wt coextruded laminates of these polybutadienes with PVC of different composition and a polyethylene tubing were evaluated. The higher the Shore hardness of the PVC tubing, the lower the sorption. The infusion fluid played an additional role only for the tubings with high Shore hardness (greater than 70). The sorption of isosorbide dinitrate to polybutadiene tubings of different mol. wt was less than 2.5% after 5 h and was comparable with the sorption to the polyethylene tubing. When polybutadiene/PVC laminates were used, the sorption increased significantly and was in most cases dependent on the Shore hardness of the PVC (higher Shore hardness gave lower sorptions) and on the mol. wt of the polybutadiene (lower mol. wt resulted in higher sorption). Sorption was not dependent on the type of PVC plasticizer.

Adsorption↗
PubMed1991

Positron emission tomographic studies of changes in cerebral blood flow and oxygen metabolism in neuroleptic malignant syndrome.

Three patients with neuroleptic malignant syndrome were studied by positron emission tomography (PET), using the steady-state technique with C15O2 and 15O2. In 2 patients the PET examination was repeated after resolution of the syndrome. In 2 patients, under treatment with bromocriptine, high blood flow and oxygen metabolism were demonstrated in the striatum, cerebellum and occipital cerebral cortex during the neuroleptic malignant phase, showing that not only the dopaminergic system is disturbed but also other neurotransmitter systems are involved. In the 3rd case the PET scan findings were not as conclusive.

Adult↗
PubMed1991

Influence of chest physiotherapy on arterial oxygen saturation.

Two groups of ventilated patients were compared for chest physical therapy on an ICU: respiratory insufficient patients on one side and a control population on the other were submitted either to percussion or vibration therapy, and to postural drainage. Our data show a decrease in arterial oxygen saturation after CPT and after 2h monitoring; the lateral position results in a better SaO2 in the pneumonia group while SaO2 tend to decrease in the control population. However, no significant therapeutic influence of vibration nor percussion was found. Our data suggest CPT does not result in a short term respiratory benefit. Further investigations with prolonged sessions of postural drainage are required.

Adult↗
PubMed1991

Measured attenuation correction using the Maximum Likelihood algorithm.

Quantitative determination of local radioactivity concentration in positron emission tomography (PET) requires a good attenuation correction procedure to reconstruct the emission image. Using a similar Maximum Likelihood (ML) algorithm as for the reconstruction of the emission image, a method is proposed to reconstruct a transmission image, i.e. a map of absorption coefficients. This reconstructed transmission image is then used to calculate the attenuation correction factors needed for the ML reconstruction of the emission image. This approach takes automatically into account the convolution step in the acquisition process (caused by various smoothing factors, e.g. the detector width). This results in appreciable noise suppression without loss of resolution due to filtering, thus making the reconstructed images easier to interpret. A comparison is made with other estimates for the measured attenuation correction using phantom studies.

Algorithms↗
PubMed1990

Prompt recovery from severe cholinesterase-inhibitor poisoning--remarks on classification and therapy of organophosphate poisoning.

In organophosphate intoxication the assessment of both the degree of severity of poisoning and the initial dose of pralidoxime and atropine are as yet based only on clinical symptoms. We present three patients with clinically severe organophosphate poisoning in whom a prompt recovery from central nervous symptoms occurred after the administration of low doses of atropine and pralidoxime. It is suggested that the true severity of organophosphate intoxication as well as the initial therapy should be determined by the amount ingested, the propensity for aging, and the pharmacodynamic properties of the organophosphorus compound, as well as by the time interval between exposure and initiation of appropriate treatment, as far as these data can be verified in the individual patient.

Acetylcholinesterase↗
PubMed1990

Production of carrier-free 66Ga and labeling of antimyosin antibody for positron imaging of acute myocardial infarction.

A method for labeling monoclonal antimyosin antibodies with 66Ga is described. The radionuclide is a positron emitter (t1/2: 9.4h) produced by means of the 63Cu (4He, n) 66Ga reaction. Purification of the 66Ga from the copper target is described in detail. Monoclonal antimyosin antibodies are labeled with 66Ga at a high yield (99%) by transcomplexation from an acetate buffer with the diethylenetriamine pentaacetic acid (DTPA)-labeled antibody and preliminary evaluated in two dogs for imaging of myocardial necrosis by positron emission tomography.

Animals↗
PubMed1990

The sorption of isosorbide-5-mononitrate to intravenous delivery systems.

The sorption of isosorbide-5-mononitrate, diluted in 0.9% NaCl or 10% glucose solutions, to intravenous delivery systems was investigated. Infusion bags, burettes, a syringe, infusion tubings and end-line filters were tested in static and in dynamic experiments. No clinically significant sorption was detected during those experiments. The use of PVC tubings of different hardness did not influence the results.

Adsorption↗
PubMed1990

Differential effects of vasodilators on forearm and calf vessels.

Because the literature comparing the effects of vasodilators on forearm and calf vessels is very scarce, the authors compared different vasodilators used in cardiovascular medicine in a group of volunteers. The peripheral effects were measured in the sitting position by plethysmography at the calf and at the forearm. At the forearm, comparable dilator effects were seen in arteries and veins. At the calf there was a trend for arterial flow to decrease as venous capacitance increased. Vascular response seen in one limb was not representative of the whole circulation. The changes observed were dependent not only on the vascular area investigated but also on the dose used.

Adult↗
PubMed1990

Clinical evaluation of pulse oximetry monitors on critically ill patients.

Four pulse oximeters and two pulse oximeter-capnographs were evaluated on accuracy of measuring oxygen saturation and heartrate for the former and oxygen saturation, heartrate, respiratory rate and capnography for the latter. In the first part of the study four pulse oximeters (Criticare Systems Model 501 +, Ohmeda Biox 3700 Pulse Oximeter, Nellcor Model N 100 and Datex Satlite) were simultaneously studied on 10 ventilated ICU patients. Fifty simultaneous measurements were done for heartrate and oxygen saturation and compared to arterial saturations and ECG heartrates. Mean differences from pulse oximeter values versus control arterial and ECG values were within two percent for the four instruments. In the second part two oxicaps (Ohmeda 4700 and Nellcor N 1000) were evaluated with the same control parameters. Thirty measurements on 3 patients were done. As in the first part of the study all results were accurate within two percent of control values. From those data we can conclude that all examined monitors were fairly accurate compared to simultaneous arterial blood gas analysis and ECG monitoring. The oxicap monitors have the advantage of giving continuous information on two very important parameters of patient monitoring: CO2 and saturation.

Adult↗
PubMed1990

Serum tumor necrosis factor levels in patients with infectious disease and septic shock.

The role of tumor necrosis factor (TNF-alpha) in the pathogenesis of septic shock has been assessed by daily measurements of serum TNF-alpha levels in 60 patients admitted to the medical intensive care unit. All patients in the study had infectious disease and were at risk for the development of sepsis and septic shock. Sepsis was diagnosed in 34 patients, 24 of whom died (six within the first 24 hours). The 26 patients who did not evolve toward sepsis served as a control group. The clinical condition of all patients was monitored by daily APACHE II scoring. Blood was drawn once a day and additional samples were taken in patients whose clinical condition underwent sudden deterioration. TNF-alpha levels were measured with a commercially available immunoradiometric assay. At time of patient admission, TNF-alpha levels were higher in the group with sepsis than in the control group (median 79 iqr 329 vs median 0.5 iqr 5; p less than 0.001). In the group with sepsis, extremely high TNF-alpha levels were found in patients who died within 24 hours. These patients had TNF-alpha levels of 917 iqr 755 pg/ml, whereas the patients who died more than 24 hours after admission had TNF-alpha levels of 58 iqr 59 pg/ml. Survivors had lower TNF-alpha levels (26 iqr 347 pg/ml). APACHE II scores correlated with TNF-alpha levels in the total sepsis group (Spearman rank correlation coefficient 0.477; p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1989

A comparison of sotalol and procainamide in symptomatic ventricular tachycardia.

UNLABELLED: The effects of oral sotalol were compared with 1000 and 1500 mg of procainamide in 23 patients with sustained ventricular tachycardia. The predictive value of an induction study after procainamide was assessed. The mean age of the study group was 62 +/- 12 years, and the mean ejection fraction was 32 +/- 16%. The cycle length (CL) of the induced tachycardia, the coupling interval (CI) of the first extrastimulus (in ms), and the number of noninducible (NI) patients are given in the table below. (table; see text) One patient developed torsades during the loading period of sotalol and is included in the number requiring cardioversion (DC). Important proarrhythmic effects (spontaneous occurrence of tachycardia) were seen twice after procainamide. Induction suppression by procainamide predicted success with sotalol (p = 0.0013). CONCLUSION: Ventricular tachycardia seems to be less often inducible after oral sotalol than after procainamide. The success of procainamide during programmed electrical stimulation predicts the same for sotalol. If ventricular tachycardia remains inducible after oral sotalol, it is faster than after procainamide but slower than the baseline tachycardia. Both drugs slightly prolong refractoriness.

Aged↗