Biomedical subjects
Publications and source records attributed to A McVicar.
This is the third article in the Concepts in Anatomy series, based on Physiology and Anatomy, a homeostatic approach, by John Clancy and Andrew McVicar. In this article, Stevie Boyd discusses some of the problems encountered in neonatal surgery.
In this fourth article in the Concepts in Anatomy series, Anne-Marie Ramsay joins John Clancy and Andrew McVicar in examining the upper and lower gastrointestinal tract and identifies some common homeostatic imbalances. Diagnostic tests for detecting abnormalities are described, highlighting the importance of the nurse's role in caring for the patient throughout these procedures. This series is based on Physiology and Anatomy, a homeostatic approach, 2nd ed, John Clancy and Andrew McVicar (eds), Edward Arnold, London, 1995, currently in print.
Latex allergy is a subject which is causing concern both amongst healthcare workers and in the Department of Health, with reports that significant numbers of NHS staff may have latex hypersensitivity. With this informative article, Janet Cox joins John Clancy and Andrew McVicar to explain the mechanisms that underlie latex hypersensitivity and to make recommendations about how hospitals can deal more effectively with it. The article is based on the text, Physiology and Anatomy, a homeostatic approach, 2nd ed, John Clancy and Andrew McVicar, Arnold, London (in print September 2001).
In this article in our Concepts in Anatomy series, Mriga Williams joins John Clancy and Andrew McVicar in an examination of the heart, identifying and describing its component parts, its relationship to the circulatory system and some of the abnormalities it might develop. The article includes a range of activities readers may carry out to test and improve their knowledge. The series is based on the text by John Clancy and Andrew McVicar, Physiology and Anatomy--a homeostatic approach, Arnold, London (in print September 2001).
Concerns have been expressed that bioscience education is not meeting the needs of nursing students in the UK. This paper explores the situation further by comparing student perceptions with those of experienced practitioners (Part One of the study) and also evaluates the confidence of staff nurses in explaining the rationale for care applied to a common but specific disorder (influenza; Part Two). Questionnaires were used. Responses were elicited from DipHE Nursing (Project 2000) adult/child branch students (n=153) from two universities and from adult/child care staff from their local clinical placements (n=171 in Part One of study; n=266 in Part Two). The questions asked followed two themes: (1) confidence in understanding biological science and (2) issues of teaching and learning. Most questions utilized a rating scale from 1 to 10; this scale provides no central value and a vertical line was drawn to encourage respondents to identify which half of the scale their responses came under (basically, a negative or positive viewpoint). The significance of the data distribution either side of the midline was analysed statistically (simple sign test), as were any differences in distribution between the groups (chi-square test). Median values were also determined. The data do not provide support for views that the biosciences are being significantly diminished by modern curricula, but also show no evidence for a great improvement in the bioscience knowledge base in recent years. What was surprising was the lack of confidence expressed by staff nurses: one illuminating finding was the lack of confidence in articulating their knowledge to patients and, even less so, to other health professionals. The paper reiterates a need for a national teaching and learning strategy for pre- and postregistration education in the biosciences. In particular, a means to raise the level of understanding of staff nurses must be identified urgently so that the mentoring of students in these subjects is improved.
This series of articles will draw on Physiology and Anatomy, a homeostatic approach (hereafter referred to as 'the reader'), written by John Clancy and Andrew McVicar. There will also be cross-references to the series of articles entitled 'Homeostasis--the key concept to physiological control' published in the British Journal of Theatre Nursing 1996-98. The articles will include some activities which the readers can carry out to test their understanding and deepen their knowledge base of the anatomy explored in each article. The introductory article will cover the common anatomical structures involved in the 'surgical approach', looking first at the anatomy and then relating it to surgical practice. Homeostasis is the key underlying principle to which the surgical practice will refer.
This is the second of a series of articles based on Physiology and Anatomy, a homeostatic approach by John Clancy and Andrew McVicar. This article looks at the musculo-skeletal system, with particular emphasis on the spine. It identifies spinal deformities, injuries and maladies, and various types of surgical intervention.
Pain is a complex phenomenon to which an individual's response is determined by the interactions of physical, psychological, cultural and social factors (Melzack and Wall, 1988; Woodward, 1995; Horn and Munafo, 1997). It cannot be measured, and self-assessment by patients is increasingly recognized as the most accurate means of evaluating their pain. However, research indicates that even self-assessment remains problematic because nurses frequently either do not use pain tools effectively, or do not always accept the self-assessment. Reasons for this seem to be rooted in the attitudes and beliefs of nurses, and inadequate communication. The latter problem could be improved by more effective use of pain tools, but attitudinal problems are more difficult to address once the barriers have become established. This article suggests that the most effective way to prevent such barriers arising is to ensure that nurses receive a focused, substantive input on pain assessment and pain control within their preregistration studies. Referring to proposals put forward several years ago by the Royal College of Nursing (Davis and Seers, 1991), the authors suggest that the process should begin very early in preregistration studies, preferably within the first 6 months, and involve teaching and learning strategies that encourage personal exploration and so are conducive to personal growth and development. In this way, postregistration studies could realistically focus on specialist aspects of pain care more appropriate to 'continuing education'.
In the first of these two articles, Davies and McVicar (2000) reviewed issues regarding pain assessment and examined the best means of providing the underpinning education. In the second article, pain management issues are considered while focusing on the factors that influence the translation of planned care into action. The literature identifies that inadequate pain control continues to be a problem and, assessment issues apart, suggests that a lack of knowledge of analgesic pharmacology, and resultant misconceptions among both health professionals and patients, are major factors. This article provides an overview of the rationale for the use of analgesics by considering their biological actions, how the drugs fit into the analgesic 'ladder' (World Health Organization (WHO), 1994), and how they relate to the principles of managing chronic pain. The most common misconceptions concern the use of morphine and arise as a consequence of a lack of understanding of this drug. Further issues relating to the multidimensional aspects of pain and the need for psychosocial care and sound re-evaluations of the continuing effectiveness of pain control are identified. Finally, some of the professional issues that affect the transference of assessment and knowledge are examined. Nurses have a pivotal role in pain assessment and it is suggested that education must play a role in the development of genuine interprofessional working which will allow nurses to have more influence in formulating the care strategy and subsequent action.
In this series of articles we have illustrated how physiological processes enable adaptation to changing situations such as those associated with surgery. Homeostasis has formed the central theme for relating physiology to well being, and the articles have largely been concerned with the homeostatic regulation of specific systems or processes within the body (a list of articles in the series is provided at the end of this one). This final article maintains the theme but is concerned with the broader, whole-body responses that occur when the body is subjected to the trauma of surgery. Some of these responses have briefly been touched upon in earlier articles, but are expanded upon here to illustrate the adaptability of metabolic homeostasis when the body has been injured.
The assessment and management of perioperative pain are critical skills for the surgical nurse, hence, the subjective nature of pain should be reflected in their approach to pain control. Unfortunately, many studies (Seers 1987, Kuhns et al 1990, Royal College of Surgeons and Royal College of Anaesthetists 1990, Closs 1992 and Field 1996) suggest that the nurse's knowledge of perioperative management is inadequate. However, as Carr (1997) reported, nurses are not the only group of health care professionals who demonstrate a lack of 'expertise' in providing analgesic relief. Carr reviewed the survey of 27 medical schools by Marcer and Deighton in 1988 which revealed that 4 schools undertook no formal teaching on pain control, and the remainder averaged only 3.5 hours during a four year course. Clearly, perioperative pain management remains a major problem! We have suggested that surgical nurses must have a sound knowledge of the neurophysiology associated with this subjective phenomenon (Clancy and McVicar 1998) since such an understanding is paramount in assisting the decision making process which underpins effective individualised perioperative pain management.
Blood gas homeostasis is a vital part of the process of maintaining tissue oxygenation and in preventing acidosis arising from carbon dioxide accumulation. There is a need, therefore, for homeostatic processes to control lung function if tissue functions elsewhere are to be supported. The partial pressures of blood gases reflect those occurring within the lung alveoli during breathing but should be viewed as being representative of average alveolar composition since regional variation in the composition of alveolar gas exists within the lungs. Inadequate alveolar ventilation, changes in the regional distribution of ventilation or blood flow, and alterations to the alveolar-capillary membrane across which the gases must diffuse result in a failure to maintain blood gas homeostasis. The control of lung function is normally very precise but it is susceptible to extrinsic factors. It is important that nurses are aware of the risk of respiratory complication during and after surgery, and of the difficulties of providing effective therapies. Risk reduction and the need for monitoring should figure highly in care planning and delivery. Basic methods such as monitoring pulse rate and body temperature during recovery or in the post-surgical period can identify problems since hypoxaemia promotes a tachycardia and often pyrexia. These may be symptomatic of other problems, of course, and so are important means of detecting a variety of homeostatic failures.
Immunity is a response to the invasion of the body by non-self antigens (Figure 8). Immunity is characterised by being: Xenophobic--it distinguishes self from non-self components. Adaptive--it produces a response to an antigenic invasion. Highly specific--its response is personal for different antigenic insults. Anamnestic--its memory component allows the occurrence of primary and secondary responses.
Infusates are used to expand the intravascular volume or to influence solute composition of body fluids. The choice of infusate depends on the underlying physiological disturbances. A variety of infusates are used and it is important that the consequences of over-infusion are understood.
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Water in the body forms the fluid compartments inside and outside cells, but it is more than just a space filler. A continuous exchange of water between the compartments partly facilitates regulation of the compartment volume but also permits the exchange of substances dissolved within it. Some of these latter are ions that form the electrolyte environment in which cells must operate. Body fluid physiology is concerned with the actions and regulation of the major electrolyte constituents. The use of infusions provides clinicians with the means of supporting this physiology when homeostatic mechanisms have failed or are insufficient to meet demands.
The maintenance of body water content is a classic example of homeostasis at work. Water is continuously lost and added to the systems. The regulation of a balance between the factors involved demonstrates the dynamic nature of homeostatic processes. Surgery places additional demands on such processes, partly because there are additional factors in the balance equation and partly because of the hormonal responses to trauma which also affect water balance. Promoting the return to a balance state and maintaining it, during and after surgery, is important to patient well-being and may even facilitate recovery. The risks associated with a disturbance in water balance are of potentially greater consequence if there is water overload, particularly if the patient has underlying cardiovascular or respiratory problems. Slight dehydration is probably a better target to aim for in order to reduce such risk but there are no easy ways to achieve this state as individuals will vary in their responses to surgery. The hydration, and electrolyte, needs, will vary between patients so fluid therapies should be individualised. Whilst a patient's fluid balance chart provides a means of assessing water balance, the interpretation is complicated after surgery. An awareness of other signs is therefore essential.