Understanding Fever and Body Temperature

A Cross-disciplinary Approach to Clinical Practice

Ewa Grodzinsky,Märta Sund Levander

• Publisher: Palgrave Macmillan
• Year: 2019
• ISBN:
  9783030218867
• Topic: Negocios y empresa
• Subtopic: Industria farmacéutica, biotecnológica y sanitaria

This book covers several areas, such as immunology, infectious diseases, physiology, general nursing, and medicine as well as measurement accuracy and the history of our understanding of fever. This book employs an interdisciplinary approach to exploring our concept of body temperature and specifically fever. The present volume revolves around thermometry, taking the reader on a journey from the past to the present. Yet while the emphasis is on the clinical importance of obtaining accurate, quantitative measurements of body temperature, the reader is also introduced to the most recent clinical work on the subject. This book represents a truly cross-disciplinary collaboration, using evidence-based practice to integrate physiological and immunological knowledge. The authors' intention with this volume is to help readers gain better insight into the importance of using knowledge from different disciplines to develop an appreciation of the different aspects of body temperature. In addition, the reader will come to understand the concept of fever in a broader perspective than is traditionally adopted.

© The Author(s) 2020

E. Grodzinsky, M. Sund Levander (eds.)Understanding Fever and Body Temperaturehttps://doi.org/10.1007/978-3-030-21886-7_1

Begin Abstract

1. Introduction to Understanding Fever and Body Temperature

Ewa Grodzinsky¹ and Märta Sund Levander²

(1)

Department of Pharmaceutic Research, Linköping University, Linköping, Sweden

(2)

Department of Nursing, Linköping University, Linköping, Sweden

Ewa Grodzinsky (Corresponding author)

Märta Sund Levander

Email: [email protected]

End Abstract

The year 1871 saw the publication of the magisterial work Medical Thermometry and Human Temperature. Based on exhaustive measurements of axillary temperature by the German physician Carl August Wunderlich (1815–1910), the book was the first to define normal body temperature as 37.0 °C (98.6 °F) and 38.0 °C (100 °F) as fever. However, at that time, the physiological mechanisms of thermoregulation were not known, there was little knowledge of immunology and microbiology, and the technology needed for accurate clinical thermometers was in its infancy. Also, Wunderlich’s measurements were performed on patients, suggesting that a large number of them may have been febrile. In the late nineteenth century, the English physician Sir Thomas Clifford Allbutt introduced the shorter clinical rectal mercury thermometer, which was later followed by the oral mercury thermometer. It was not until the 1960s that digital devices were introduced together with new techniques for non-invasive measurement of body temperature. The most recently developed thermometers use infrared radiation to estimate body temperature.

Besides advances in the technical aspects of thermometers, there has been progress in the understanding of the physiological and immunological processes which influence body temperature. However, thermoregulation, in terms of the diurnal rhythm and the physiological mechanisms which maintain a stable and balanced internal environment, was not understood until the 1950s. The role of female hormones was not appreciated until the 1970s. By that time, immunology and the full complexity of the immune system—the body’s defense mechanism for removing foreign agents and restoring tissue structure and physiological function—was beginning to be understood.

The effect of antipyretics on body temperature had been known for decades, as had the results of treatment with penicillin and sulfonamide, but antipyretic use in clinical practice did not become common until the 1970s. During the same decade there was a significant improvement in laboratory methods, making it possible to understand in more detail the effector mechanisms used to eliminate foreign agents and protect the body from destruction, particularly the role of various cells and cytokines. In the 1990s, quality assurance and patient safety were highlighted, and today they are permanent obligations within health care. Together with the demand for evidence-based decision-making, this now forms the basis for ensuring good care. However, even though there has been tremendous development, progress has advanced along two parallel lines (Fig. 1.1).

Fig. 1.1

The development of thermometry and physiological and immunological knowledge in relation to assessment of body temperature. (Copyright Grodzinsky, E & Sund Levander, M)

This parallel development has had great impact on current practices and perceptions about body temperature. The concept of fever influences clinical assessment and evaluations of body temperature, and still has a significant impact on decisions in nursing care, medical diagnosis and treatment, and in the ordering of laboratory tests. Today, although there is a general acceptance that body temperature adopts a range of values rather than a fixed temperature, the norm arrived at in the mid-nineteenth century is still the basis for assessment and decisions about body temperature worldwide. In addition, even if the technical accuracy of measurements has become much better, clinical accuracy, meaning knowledge about physical influences on the individual’s body temperature, such as thermoregulation and hormones, immunological defense against microbes, and the development of laboratory assays, is still not considered important for body temperature assessment. For example, due to the temperature gradients between different sites of measurement, it is impossible to measure or define the ‘actual’ body temperature as no factor exists which allows accurate conversion of temperatures recorded at one site to estimate the temperature at another. Also, in addition to the temperature differences between different sites in the same individual, there are considerable differences in body temperature between individuals, and therefore we have to assess changes in body temperature as the difference between an individual baseline body temperature and the measured reading, so-called DiffTemp™, and not use a predetermined, universal cut-off value.

When we say that someone has a ‘fever’, what do we really mean? In the first instance most people think of fever as equating to an elevated body temperature because of infectious disease. In fact, it is common to ‘measure fever’ more than to measure body temperature. However, fever is essentially defined as:

a state of elevated core body temperature, which is often, but not necessarily, part of the defense of multicellular organisms (the host) against the invasion of live (microorganisms) or inanimate matter recognized as pathogenic or alien by the host. (IUPS TC. Glossary of Terms to Thermal Physiology. Pflugers Archives 1987, 410: 567–87)

Fever is thus part of a larger response in the body, in which many different cells are activated and react in what is called the acute phase response. This response does not mean that the body temperature is permanently elevated or that we experience the activity of the immune cells in the form of malaise. Immune cells may be continually active, day and night, without reaching the level of inflammation.

Taken together, a great deal is known about thermoregulation, and the factors influencing body temperature, from a technical and physiological viewpoint. It is of great importance to base the assessment and evaluation of temperature on evidence-based medicine and not on tradition or personal belief. Therefore, it is necessary to use knowledge from both of the two parallel lines and to integrate this knowledge to form a basis for evidence-based practice.

In order to use this knowledge in evidence-based practice, collaboration is necessary between professionals and between disciplines such as health care, laboratory science, and medical technology. In the clinical context, this means that health care personnel should work together to provide care which is both high quality and safe. This emphasizes the importance of teamwork and inter-professional learning (IPL), in the form of collaborative practice, inter-professional communication, and respect for one another’s competence, so that the group may use their joint expertise to achieve excellence (Fig. 1.2).

Fig. 1.2

Evidence-based practice based on integration of the two parallel lines of technique and physiological and immunological knowledge in relation to assessment of body temperature. (Copyright Grodzinsky, E & Sund Levander, M)

The pedagogical approach of this textbook is problem-based learning (PBL). PBL is based on the acquisition of knowledge by problem-solving, using self-directed learning, and a scientific and critical approach. Here, the basis of PBL is inter-professional discussions of scenarios from clinical practice. Such discussion stimulates reflection, and the problem-solving process makes the knowledge accessible and easier to apply in real situations. Our intention with this textbook is that the reader will gain insight into the importance of using knowledge from different disciplines to develop an appreciation of the different aspects of body temperature. In addition, the reader will come to understand the concept of fever in a broader perspective than that traditionally adopted. The book is based on research in the fields of physiology, immunology, laboratory science, nursing care, metrology, technological and scientific developments, and measurement with clinical thermometers related to body temperature. In some chapters, well-established knowledge is presented, along with a recommendation for a general reference source such as a reputable textbook.

However, to understand today’s ideas and concepts, we have to consider the perceptions of the past. Therefore, the book starts with two chapters (Chaps. 2 and 3) examining the historical perspective. The following chapters (Chaps. 4, 5, and 6) focus on technical measurement accuracy an...