Biomedical subjects
Publications and source records attributed to J Petersen.
Two cases of adolescent females attempting self-induced abortions are presented. Many ramifications and complications of illegal abortions are discussed as they affect the patient and society. In addition, we discuss the future of medical education as well as the economic aspects of health care in relationship to illegal abortions.
Explore the source record for details and available documents.
Considering the fundamental difficulties to define the term 'depth of anaesthesia', a more feasible concept for assessment of 'adequacy of anaesthesia' will be explained. The basic requirements for a monitoring index are definite response, gradual scaling and independence from the anaesthetic technique used. Additionally the index should be predictive for appearance of clinical signs of an inadequate anaesthesia. Different signal-processing methods will be discussed to extract the relevant information from both the spontaneous and the evoked brain electrical activity. In this context well established methods like spectral analysis are investigated in combination with new and more sophisticated methods like bispectral analysis or wavelet decomposition. Since no single-parameter index has been defined for monitoring depth of anaesthesia, a set of EEG parameters may be more useful to take into account intra- and interindividual variability. In parallel to the description of the monitor concept, the investigation of neural nets and fuzzy techniques, in addition to or in substitution of conventional statistical methods, will be introduced. Examples are given for data quality assessment, parameter extraction and re-classification.
The clearance of urea and beta 2-microglobulin are important considerations along with biocompatibility in selecting membranes for use in shortened dialysis. During 3 hr of dialysis we have measured the in vivo urea clearances, pre- and post-beta 2-M levels, plasma clearance and simultaneous dialysance of beta 2-M. Leucopenia was compared after 15 min of dialysis on a cellulose acetate (CA) dialyzer and a polyacrylonitrile dialyzer (PAN). Clearance of urea was similar in both dialyzers. In contrast to CA, PAN removed beta 2-M and exhibited minimal leucopenia. The dialysance of beta 2-M was significantly less than the simultaneous blood side clearance. The disparity between blood clearance and dialysance by PAN membranes suggests removal of beta 2-M by adsorption and diffusion. We conclude that in comparison with CA dialyzers, PAN membranes remove beta 2-M, have equivalent urea clearances, and are more biocompatible.
Recent Occupational Safety and Health Administration guidelines require the implementation of needleless systems in dialysis units in the state of California. It is not known whether needleless systems deliver medication as well as traditional low dead-space needle/syringes. The purpose of this study was to compare the delivery of recombinant human erythropoietin (rHuEpo) by a needleless system (Medic Plastic Anti-Stick Needle/Connector, Medisystems, Seattle, WA) with delivery using a traditional low dead-space needle/syringe. We also studied the Medisystems High Flow venous chamber with integral injection site that is designed to prevent the formation of a separate serum layer within which rHuEpo may become trapped. There was no significant difference in the mean serum rHuEpo concentration achieved by either the needleless system, or traditional low dead-space needle/syringe, whether using the venous chamber's integral injection site or the postvenous chamber in-line injection site. This study demonstrates for the first time that a needleless system of delivery can reliably achieve serum rHuEpo comparable to traditional low dead-space needle/syringes.
Explore the source record for details and available documents.
Prostate cancer is the third leading cause of death from cancer among men in the United States. Traditional treatments for prostate cancer are prostatectomy, external beam irradiation, and interstitial implantation of Iodine125 (I125) via laparotomy. These treatments are associated with significant morbidity and limitations. Based on experience with I125 interstitial implantation by transrectal ultrasound guidance for early-stage prostate cancer, it seems that this newer method of treatment has greater accuracy of placement and distribution of the isotope and has had few reported complications. The need for a surgical incision has been eliminated. Hospitalization time also has been decreased, creating the need for ambulatory and inpatient nurses to understand the importance of their respective roles in providing coordinated quality care for these patients. Nurses in these departments must have knowledge of the procedure, radiation safety, and common side effects related to the implant.
The authors have studied the sequential changes in hemodynamic responses and Atrial Natriuretic Peptide (ANP) levels following bicarbonate hemodialysis with fluid removal followed by an infusion of saline and then ultrafiltration of the added fluid. Cardiac output, stroke volume, and thoracic fluid index (TFI) were measured by transthoracic impedence cardiography. Left cardiac work index (LCWI) was derived using these hemodynamic and mean arterial pressure (MAP) measurements. MAP was lower following dialysis when compared to pure ultrafiltration of a similar fluid loss. LCWI decreased during both dialysis and ultrafiltration. TFI, which is inversely related to intrathoracic fluid, increased following dialysis and ultrafiltration. ANP levels fell following fluid removal but remained elevated above normal control levels. The authors conclude that ANP levels are related to fluid not cardiac status in dialysis patients and that impedence cardiography is of value in determining hemodynamic and fluid changes during dialysis.
In order to determine the degree to which blood and dialysate achieve equilibration of urea concentration during continuous arteriovenous hemodialysis (CAVHD), CAVHD circuits employing the Hospal AN69S dialyzer were perfused with bovine blood (85 to 90 ml/min, hematocrit 28%) containing 50 mg/dl of urea in the presence of countercurrent dialysate flowing at 10, 20, or 30 ml/min. The circuits were constructed and perfusion pressure (66 mmHg) set to yield a near zero net ultrafiltration rate. Urea clearances were measured and found to approximate the dialysate inflow rate, Qd, up to about 15 ml/min. At higher dialysate flow rates, equilibration was incomplete so that urea clearance was 24.7 +/- 0.5 (mean +/- SE) ml/min when Qd was 30 ml/min. A simplified model of urea transport in the dialyzer successfully simulated the data.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The gap between preservice preparation of nurses for critical-care work and employers' expectations is a crucial factor in providing safe care in special-care units. In this study of senior nursing students from 32 Midwestern schools of nursing, it was found that about 75 per cent of the students had had some experience in critical care, with a mean of 46 hours of experience. Most students observed, did selected procedures, or helped a staff nurse. Only 3 per cent planned and carried out care for more than one patient at a time. Fifty-eight per cent considered themselves unprepared to work in areas of critical care and needed more practice and theoretical instruction. There was wide variation in adequacy of instruction in frequently-used assessment and management techniques.
Explore the source record for details and available documents.
The pharmacokinetics of intravenous recombinant erythropoietin administered during or after dialysis were studied by multicompartmental analysis in eight patients with end-stage renal disease to determine whether significant loss of the drug occurred during the hemodialysis procedure. Each patient had five studies, one in which the erythropoietin was given near the end of a dialysis session (baseline). In the other studies, erythropoietin was administered at the beginning of hemodialysis for 4 hrs using each of four different dialysis membranes. Both two compartment and three compartment models were used. In the two compartment solutions, the mass of the exchange compartment was significantly increased in the studies done during dialysis compared with the baseline. Clearance did not change significantly among the study sessions. When a third compartment, representing the dialysis system, was added, the kinetics of the internal exchange compartment and of the dialysis system could be determined separately. At the end of 4 hrs of dialysis after the erythropoietin dose, the dialysis systems contained an average of 7% of the administered dose. It was concluded that hemodialysis immediately after erythropoietin administration does not affect the rate of erythropoietin loss, except for small losses in the dialysis system itself when it is removed at the termination of the procedure.
Serum concentrations of rHuEPO were measured after injection into different sites within the blood lines in patients undergoing hemodialysis. The authors compared the venous port to venous drip chamber injection using two separate delivery systems and their associated blood lines (Cobe Centry 3 [CGH, Lakewood, CO] and Fresenius A2008 [Fresenius USA, Concord, CA]). The former has a unique cartridge drip chamber and the latter a more conventional set-up. Patients were injected at both sites with their usual dose of rHuEPO at the beginning of dialysis and plasma levels were measured throughout dialysis. Significantly lower plasma levels occurred only after injection into the venous drip chamber using the Fresenius delivery system. Simultaneous samples were drawn from the venous and arterial ports and upper and lower drip chamber in a group of patients dialyzing on this system. Levels were 26 and 32 times higher in the upper and lower drip chamber compared to the venous sample, which exceeded the arterial sample. No significant rebound of rHuEPO was detected at the end of dialysis after saline rinse back in patients in whom the rHuEPO was injected into the drip chamber. The authors conclude that injection of erythropoietin into the venous drip chamber of the Fresenius delivery system should be avoided because substantial quantities are lost by "trapping," and not eluted at the end of dialysis.