Biomedical subjects

M J Oliver

Publications and source records attributed to M J Oliver.

39 records · Page 3Linked to original sources

PubMedDate not supplied

Acute dialysis catheters.

Acute dialysis catheters are non-cuffed, non-tunnelled catheters used for immediate vascular access. They are primarily used for acute renal failure in bed-bound patients and for short-term use in patients with malfunction of permanent access. Long-term use of acute catheters is not recommended, but does occur with acceptable infection rates in dialysis centers where tunnelled, cuffed catheters are not available. Most acute catheters are made of polyurethane, but silicone catheters are now available with larger lumen sizes capable of delivering blood flow rates over 300 ml/min. Acute catheters should be inserted in the internal jugular or femoral vein under ultrasound guidance to minimize complications. Subclavian catheters cause stenosis, thrombosis, and perforation of vessels. Intermittent catheter malfunction still occurs, particularly for left-sided internal jugular catheters and catheters placed in women. Blood flow may improve with lumen reversal, intraluminal t-PA, or guidewire exchange. Limiting duration of use and dressing catheter exit sites with dry gauze and antiseptic ointments can prevent catheter-related infections.

Acute Kidney Injury↗

PubMedDate not supplied

Neutron fluence and kerma spectra of a p(66)/Be(40) clinical source.

High-resolution neutron fluence spectra have been measured in the National Accelerator Centre's p(66)/Be(40) neutron therapy beam by the pulsed-beam time-of-flight method. ICRU muscle kerma spectra have been derived from the fluence spectra. Spectral changes resulting from different irradiation conditions have been quantified in terms of the average neutron energy and the fractional low-energy (< 16 MeV) contribution. The changes observed with different thicknesses of polyethylene filtration are consistent with changes in quality parameters determined in biological and microdosimetric experiments. The dosimetry parameters (KtissueA150) N and (Wgas) N calculated for the measured spectra agree with the values recommended in the neutron dosimetry protocol. The shapes of the present fluence spectra differ from previous measurements of p(> 40)/Be spectra. In particular, they differ significantly from the spectrum measured by recoil techniques in an identical neutron therapy unit at the Clatterbridge Hospital, UK. The reasons for the difference are not known.

Beryllium↗

PubMedDate not supplied

["All in one" parenteral nutrition: is it that safe?].

The use of "all in one" admixtures is supported by an extensive number of studies and by many years of experience. However, we detected stability problems in some mixtures whose stability was previously reported. We made modifications in one of these mixtures [composed of 1.000 ml Freamine 8.5%, 100 ml 10% dextrose, 500 ml water, 500 ml Intralipid 20%, 75 ml electrolyte solution (Na 75 mEq, K 60 mEq, Ca 15 mEg, Mg 15 mEq, Cl 90 mEq, acetate 75 mEq)] in order to see how the different components affect the emulsion stability. All the admixtures were visually inspected after storage during 24 hour at room temperature. It was observed that admixtures with low glucose concentration, high electrolyte levels and high volume were less stable than admixtures containing high glucose, low electrolyte and low volume. Amino acid concentration did not increased the stability as expected. MCT/LCT emulsions were more stable than LCT emulsions. More studies are needed to explain the stability problems of these TPN solutions.

Amino Acids↗