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Biomedical subjects

S Faithfull

Publications and source records attributed to S Faithfull.

At least 19 recordsLinked to original sources
PubMed1999

Effect of acute normovolemic hemodilution on distribution of blood flow and tissue oxygenation in dog skeletal muscle.

Acute normovolemic hemodilution (ANH) is efficient in reducing allogenic blood transfusion needs during elective surgery. Tissue oxygenation is maintained by increased cardiac output and oxygen extraction and, presumably, a more homogeneous tissue perfusion. The aim of this study was to investigate blood flow distribution and oxygenation of skeletal muscle. ANH from hematocrit of 36 +/- 3 to 20 +/- 1% was performed in 22 splenectomized, anesthetized beagles (17 analyzed) ventilated with room air. Normovolemia was confirmed by measurement of blood volume. Distribution of perfusion within skeletal muscle was determined by using radioactive microspheres. Tissue oxygen partial pressure was assessed with a polarographic platinum surface electrode. Cardiac index (3.69 +/- 0.79 vs. 4.79 +/- 0.73 l. min-1. m-2) and muscle perfusion (4.07 +/- 0.44 vs. 5.18 +/- 0.36 ml. 100 g-1. min-1) were increased at hematocrit of 20%. Oxygen delivery to skeletal muscle was reduced to 74% of baseline values (0.64 +/- 0.06 vs. 0.48 +/- 0.03 ml O2. 100 g-1. min-1). Nevertheless, tissue PO2 was preserved (27.4 +/- 1.3 vs. 29.9 +/- 1. 4 Torr). Heterogeneity of muscle perfusion (relative dispersion) was reduced after ANH (20.0 +/- 2.2 vs. 13.9 +/- 1.5%). We conclude that a more homogeneous distribution of perfusion is one mechanism for the preservation of tissue oxygenation after moderate ANH, despite reduced oxygen delivery.

Animals↗
PubMed1998

IV perflubron emulsion versus autologous transfusion in severe normovolemic anemia: effects on left ventricular perfusion and function.

Intact cardiac compensatory mechanisms are necessary to maintain adequate tissue oxygenation during acute normovolemic hemodilution (ANH). Left ventricular (LV) perfusion, oxygenation and function were analyzed in an experimental whole-body model of profound ANH (Hct 9%) and effectiveness of a perfluorocarbon-based oxygen carrier in maintaining myocardial oxygenation and function was evaluated. A total of 22 anesthetized dogs were hemodiluted to Hct 20% followed by a simulated, controlled blood-loss phase in which dogs were randomized to either: (1) 1:1 exchange of lost blood with autologous red blood cells (RBC-group), (2) 1:1 exchange with a colloid (control-group) and (3) 1:1 exchange with a colloid after a single dose of 1.8 g/kg BW perflubron i.v. (PFC-group). Myocardial oxygen delivery and consumption as well as endocardial perfusion were determined using radioactive microspheres. LV myocardial contractility (LV MC) was assessed from: (1) the relationship between maximum rate of LV pressure increase (LVdp/dtmax) and LV enddiastolic volume (LVEDV) and (2) analysis of the LV endsystolic pressure volume relationship (ESPVR). LV diastolic properties were reflected by (1) minimum rate of LV pressure increase (LVdp/dtmin), (2) slope and intercept of the enddiastolic pressure-volume relationship (EDPVR) and (3) the time-constant of isovolumic LV pressure decline "tau 1/2". Full sets of LV MC data were obtained from 18 dogs (n = 6 per group). LV MC (LVdp/dtmax-LVEDV relation) increased after perflubron administration. At the lowest Hct level, all parameters reflecting LV MC as well as LVdp/dtmin were significantly higher in the PFC-group than in the control-group. After profound normovolemic hemodilution (Hct 9%) superiority of LV MC and LV diastolic properties was found, when myocardial oxygenation was supported by i.v. perflubron emulsion, a temporary O2 carrier.

Anemia↗
PubMed1998

Somnolence syndrome in adults following cranial irradiation for primary brain tumours.

The purpose of this study was to assess the incidence, pattern and severity of somnolence and fatigue in patients treated with cranial irradiation for primary brain tumours and to identify factors that may influence or mediate symptoms. A detailed prospective study was carried out of 19 patients who received high-dose (45-55 Gy) cranial irradiation as treatment for primary brain tumours. Data were collected for each patient over a 3 month period using a prospective diary utilizing visual analogue scales of common somnolence symptoms and fatigue, and detailed interviews at 2, 6 and 12 weeks following the completion of treatment. Sixteen patients developed somnolence syndrome following treatment. Time series analysis identified a cyclical pattern to the symptoms, with a period of drowsiness and fatigue occurring from day 11 to day 21 and from day 31 to day 35 after radiotherapy. The principal symptoms were those of excessive drowsiness, feeling clumsy, an inability to concentrate, lethargy, being mentally slow and fatigue. Patients treated with accelerated (n = 11) compared with more conventional (n = 8) fractionation experienced more severe drowsiness and fatigue (P < 0.01), although there was no difference in the pattern or the incidence of symptoms. Interview data suggested that patients frequently attributed their symptoms of somnolence to 'flu or other ailments. The unexplained and overwhelming nature of the symptoms was a cause of anxiety. The prospective assessment of symptoms following radiotherapy highlighted a more detailed definition of the symptom complex and pattern of occurrence. Somnolence syndrome is a collection of symptoms consisting of drowsiness, lethargy and fatigue. Forewarning patients and planning supportive management around times of drowsiness and fatigue can help to reduce the anxiety that these symptoms cause.

Adult↗
PubMed1998

Fatigue in patients receiving radiotherapy.

The fatigue that may accompany or follow radiotherapy is often overlooked by health-care staff, yet this side-effect of treatment can cause great distress. More research into the causes and methods of relieving such symptoms is needed.

Fatigue↗
PubMed1997

Effects of hemodilution on splanchnic perfusion and hepatorenal function. I. Splanchnic perfusion.

Perfusion of intestinal organs increases in response to acute normovolemic hemodilution (ANH). However, detailed studies on distribution of regional splanchnic organ perfusion during ANH are lacking. We therefore carried out this study to test the hypothesis that ANH does not cause disturbance of physiologic patterns of regional splanchnic organ blood flow. After governmental permission, 22 anesthetized dogs were instrumented to allow invasive hemodynamic measurements and intracardial injection of radioactive microspheres (diameter 15 micro m) for determination of regional organ perfusion. Measurements were made at baseline (hematocrit 37 +/- 3%) and after ANH with 6% hydroxyethyl starch (mol. wt. 200000 / 0.5) to hct 20 +/- 1%. After completion of the protocol, splanchnic organs were removed and dissected into small samples according to anatomical and functional principles. Regional perfusion was determined based on the microsphere content of each sample. Hepatic, intestinal, and pancreatic blood flow increased with ANH. Hepatic arterial blood flow rose by 86%, whereas portal venous perfusion increased by 28%. Small intestine mucosal perfusion was augmented by 68% while the non-mucosal tissue compartment of the gut wall received 32% more blood flow after ANH which is in proportion to the increase in cardiac index after ANH. This redistribution of intestinal flow might be the basis for the preservation of tissue oxygenation during moderate isovolemic anemia.

Animals↗
PubMed1997

Effects of hemodilution on splanchnic perfusion and hepatorenal function. II. Renal perfusion and hepatorenal function.

Hepatorenal perfusion and function were assxssed in 22 dogs undergoing acute normovolemic hemodilution (ANH) to a hematocrit (Hct) of 20% using 6% hydroxyethyl starch (200.000/0.5) as the diluent. Organ perfusion was determined with the radioactive microspheres method. Renal function was assessed by urinary output, creatinine clearance and fractional sodium excretion. Blood volume as well as hepatic function were derived from indocyanine green (ICG) dilution kinetics. Hepatocellular integrity was determined by serum enzymatic activity of glutamate-oxalacetate-transaminase (GOT) and glutamate-pyruvate- transaminase (GPT). ANH to Hct 20% did not change blood volume and mean aortic pressure, while heart rate was slightly elevated (p<0.05) by 5 beats per minute and cardiac output increased by 29% (p<0.05). In contrast to the liver, where arterial and portal venous blood flow increased (86% and 28%, respectively; p<0.05), total renal blood flow as well as intraorgan distribution of renal blood flow remained unchanged post-ANH. While creatinine clearance remained unchanged following ANH, urinary output and fractional urinary excretion increased (p<0.05). In response to enhanced hepatic blood flow after ANH, intravascular half-life of ICG was reduced (p<0.05) and ICG clearance increased (p<0.05). Serum enzymatic activity of GPT decreased upon ANH (p<0.05), while GOT activity remained unchanged. ANH to a Hct 20% does not impair hepatorenal function. Increased urinary output points out the necessity for proper adjustment of crystalloid infusion to maintain normal intravascular volume and avoid hypovolemia and the associated risk of tissue hypoxia.

Animals↗
PubMed1997

Analysis of data over time: a difficult statistical issue.

The aim of this paper was to review the literature on time-series analysis and describe its use within the context of a nursing research project. The author utilized the method to investigate the symptoms of somnolence and fatigue that patients experienced following cranial irradiation for cancer. The need for longitudinal research in all areas of health care is a current concern. This is especially true in clinical areas where small patient numbers and palliative settings make large quantitative studies difficult. There are few studies or texts that help the practising researcher to explore data analysis over time in a way that reflects the time-series nature of these data. This raises questions of how to analyse such data. The study indicated that symptoms following radiotherapy were different from that previously described in the literature. Time-series analysis indicated a cyclical pattern that gave valuable information for planning supportive services. This paper explores some of the issues of time-series analysis and illustrates the process of analysis, exploring the benefits and disadvantages of this approach for research.

Clinical Nursing Research↗
PubMed1995

'Just grin and bear it and hope that it will go away': coping with urinary symptoms from pelvic radiotherapy.

Fifty per cent of patients with cancer are treated with radiotherapy during the course of their disease. Although side-effects have been described in studies, these are often not representative of the impact that these symptoms have on the individual. This article explores one area of radiotherapy management, that of pelvic radiotherapy in men, and describes how symptoms that patients experience during and following treatment can be a debilitating outcome of cancer therapy. At present, there is limited knowledge on how best to prevent symptoms from occurring, who is most at risk and how to manage these symptoms. Technology has advanced with accelerated regimes, conformal planning and new radiotherapy treatments. Yet still we are no further forward in dealing with toxicity from treatment. The focus of research has been on developing new cures and only now are questions being raised about the quality of life of patients having radiotherapy treatment.

Adaptation, Psychological↗
PubMed1994

The concept of cure in cancer care.

The concept of cure is often used in health care practices without thought to the social, cultural and psychological implications of its meaning. Frequently measured in terms of years of disease-free survival, this measure is inadequate in evaluating treatment. Iatrogenic toxicities and illness implications may linger for many months or years after a person experiences cancer. The subcultural perspectives of cure for clinicians may be very different. Historically, the clinician's concept of cure has been the focus and reported outcome of cancer treatment and research. A more dynamic view is encouraged in exploring this concept in relation to the outcomes of nursing practice.

Attitude to Health↗
PubMed1991

Patients' experiences following cranial radiotherapy: a study of the somnolence syndrome.

The aim of this study was to establish whether somnolence syndrome existed in adults by exploring their experiences after receiving cranial radiotherapy. Somnolence syndrome is described as excessive sleep, drowsiness, lethargy and anorexia and was found to occur in these patients. A description of the phenomenon was drawn from triangulation of the data. For 6 weeks following radiotherapy, the participants completed a diary consisting of two elements, a quantitative visual analogue scale and an open diary. This was followed by a qualitative semi-structured interview. Patients experienced sleepiness which they described as 'exhausted doing nothing' and that any activity was a 'struggle'. Some individuals described sensory changes, deafness and an increase in leg and arm weakness. These experiences presented a series of unexpected changes in their health which resulted in fear of treatment failure and disease recurrence. The study suggests that more information should be provided for patients on the side-effects that occur after radiotherapy has finished. Somnolence syndrome presented for the participants an experience which is not adequately described in previous literature. The nurse has an important role in providing information to prepare patients for their experience and more knowledge about this phenomenon is required for these patients to be informed adequately.

Brain Neoplasms↗
PubMedDate not supplied

Oncology: chemotherapy for elderly people.

Elderly people form a large proportion of cancer patients. This has implications for cancer care, in that age is a substantial risk factor in developing cancer. In spite of efforts to reduce cancer mortality through health education and screening, cancer rates are likely to increase in proportion to the ageing population. It has been suggested that health care professionals generally view elderly people in a negative fashion, which influences the care that these individuals receive. At present, there is a scarcity of information on the nature of cancer in elderly people, their tolerance to cytotoxic treatment, and specific age-related problems. Knowledge in all these areas remains fragmented and the research data conflicting. The nurse plays an important role in assessing and monitoring the impact of cytotoxic chemotherapy treatment. It is, therefore, imperative for cancer nurses to develop specialist knowledge in this area to enable them to understand the effect cytotoxic chemotherapy treatments have on elderly people.

Aged↗