Nursing Chronotherapeutics: A Conceptual Framework Una E. Westfall
Nurses frequently make decisions about when treatments and actions are performed. The nursing concern driving this review is the timing of nursing activities to optimize desired and minimize untoward effects. A nursing conceptual framework is proposed that highlights individual and environmental factors, as they relate to rhythmic responses, as well as places within the framework for nursing actions based on customary and usual temporal patterns. [Keywords: clinical decision making; conceptslconstructsrelated to health] t
T
herapeutics are assisting measures taken with, or on behalf of, patients and significant others to manage and reduce effects of illness and to improve and promote health and health-relatedbehaviors (Clinical Therapeutics Task Force, 1988). Nursing therapeutics are assisting measures for which nurses have decision and action responsibilities. Determining the time for an activity often is a nursing responsibility because nurses frequently sequence, implement or ensure that actions are carried out. Thus, temporal placement or timing- of measures can be viewed as a nursing therapeutic. This paper proposes a conceptual framework for timing as a nursing clinical therapeutic by: 1) clarifying characteristics of rhythms; 2) exploring timing as a clinical therapeutic; and 3) proposing a nursing chronotherapeutic conceptual framework.
Rhythms Predictable temporal patterns are ubiquitous, as exemplified by the passage of days, the ebb and flow of tides, and the changing seasons of the year. A rhythm is "a sequence of events... that repeats (itself) through time in the same order and at the same interval" (Minors & Waterhouse, 1981, p. 321). When a rhythm originates within an organism, it is said to be endogenous or selfinitiated. IMAGE: lournal of Nursing Scholarship. Volume 24, Number 4, Winter 1992
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Peak Time Peak
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Figure 1: Schematic of rhythmic characteristics.
Rhythms have common characteristics depicted in Figure 1. They can span different periods or time intervals. A common period is close to but not exactly 24 hours. Such rhythms of -24 Una E. Westfall, RN, PhD, Beta Psi, i s Assistant Professor, School of Nursing, Oregon Health Sciences University. The author thanks Linda Felver, RN, PhD and Susan Woods, RN, PhD for their contributions to the early development of ideas expressed here. Correspondence to Department of Adult Health and Illness Nursing, L-456, School of Nursing, Oregon Health SciencesUniversity, 3181 SWSamJacksonParkRoad, Portland,OR972013098. Accepted for publication January 15, 1992.
307
Nursing Chronotherapeutics:A Conceptual Framework
hours (24+4) are called circadian (circa-about, &is-day); when less than 20 hours, ultradian; when longer than28 hours, infradian. Infradian rhythms may include such time frames as multiple days (e.g., a week), a month or a year. In addition to period length, single rhythms display features of amplitude (magnitude of peak to trough [nadir] difference), peak time (when the crest or maximum value occurs, usually given in clock hours or a reference point such as midsleep, or hours after light on); level or mean (average or midpoint value of the period) and waveform (graphic composite of peak time, period, slope of ascending and descending curves, and amplitude that depicts progression from any given point to the next point characterized by the same phase). The rhythmic quality of “phase” can be used to describe temporal relationships among two or more rhythms (Minor & Waterhouse, 1981). There may be reference to rhythms being “in phase” with one another. Internal synchronization of rhythms by the body’s timekeeping system is the usual condition. An example of such a relationship is that of circadian rhythms of rest (sleep)-activity and growth hormone in adults. Normally, growth hormone plasma levels rise sharply and peak early in the sleep portion of the sleep-activity cycle. When there is time displacement of one rhythm, there can be transient desynchronization among other rhythms. Some rhythms are able to adjust to environmentalcues more quickly than others. For example, when rest-activity,temperatureand urinary excretion of sodiumrhythms were compared in humans following a time shift, rest-activity adjusted more quickly then temperature, and temperature more quickly than urinary sodium excretion (Wever, 1979). When subjects experienced a six hour phase-advance (comparable to traveling west to east across six time zones), partial entrainment with environmental cues took -3 days for rest-activity rhythm; -4 days, temperature; and -7 days, urinary sodium excretion. More detailed presentations of rhythmic phenomena are available (Arendt,Minors & Waterhouse, 1989;Minors & Waterhouse, 1981; Moore-Ede, Sulzman & Fuller, 1982).
phase). The only difference was in the clock hour, or time, of exposure. In a study with five healthy males, Moore-Ede, Meguid, Fitzpatrick, Boyden & Ball (1978) infused the same dose of intravenous potassium at noon and at midnight. The plasma potassium concentration was found to be 40 percent higher following the midnight dose than after the noon dose. More recently, in patients with constant heparin infusion rates, activated partial thromboplastin and thrombin time values differed by as much as -50 percent and 60 percent respectively between specimens drawn at night and in the morning (Decousus et al., 1985). The role that rhythms play in health and disease has yet to be clearly determined; however, there is evidence to support the view that there are times within biological rhythmic cycles when an individual’s vulnerability and resistance fluctuate (Hrushesky, 1983; Reinberg, 1967). Conceptual Framework: Nursing ChronotherapeuticModel
To examine timing as a nursing therapeutic, a proposed nursing chronotherapeutic model has been adapted from work by Heitkemper and Shaver (1989) and presented in Figure 2.
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* Alter c ti
Nurses frequently make decisions about when treatments and actions are performed. The nursing concern driving this review is the timing of nursing activities to optimize desired and minimize untoward effects. A nursing conceptual framework is proposed that highlights individual and environmental factors, as they relate to rhythmic responses, as well as places within the framework for nursing actions based on customary and usual temporal patterns. [Keywords: clinical decision making; conceptslconstructsrelated to health] t
T
herapeutics are assisting measures taken with, or on behalf of, patients and significant others to manage and reduce effects of illness and to improve and promote health and health-relatedbehaviors (Clinical Therapeutics Task Force, 1988). Nursing therapeutics are assisting measures for which nurses have decision and action responsibilities. Determining the time for an activity often is a nursing responsibility because nurses frequently sequence, implement or ensure that actions are carried out. Thus, temporal placement or timing- of measures can be viewed as a nursing therapeutic. This paper proposes a conceptual framework for timing as a nursing clinical therapeutic by: 1) clarifying characteristics of rhythms; 2) exploring timing as a clinical therapeutic; and 3) proposing a nursing chronotherapeutic conceptual framework.
Rhythms Predictable temporal patterns are ubiquitous, as exemplified by the passage of days, the ebb and flow of tides, and the changing seasons of the year. A rhythm is "a sequence of events... that repeats (itself) through time in the same order and at the same interval" (Minors & Waterhouse, 1981, p. 321). When a rhythm originates within an organism, it is said to be endogenous or selfinitiated. IMAGE: lournal of Nursing Scholarship. Volume 24, Number 4, Winter 1992
*
*
Peak Time Peak
~-
Figure 1: Schematic of rhythmic characteristics.
Rhythms have common characteristics depicted in Figure 1. They can span different periods or time intervals. A common period is close to but not exactly 24 hours. Such rhythms of -24 Una E. Westfall, RN, PhD, Beta Psi, i s Assistant Professor, School of Nursing, Oregon Health Sciences University. The author thanks Linda Felver, RN, PhD and Susan Woods, RN, PhD for their contributions to the early development of ideas expressed here. Correspondence to Department of Adult Health and Illness Nursing, L-456, School of Nursing, Oregon Health SciencesUniversity, 3181 SWSamJacksonParkRoad, Portland,OR972013098. Accepted for publication January 15, 1992.
307
Nursing Chronotherapeutics:A Conceptual Framework
hours (24+4) are called circadian (circa-about, &is-day); when less than 20 hours, ultradian; when longer than28 hours, infradian. Infradian rhythms may include such time frames as multiple days (e.g., a week), a month or a year. In addition to period length, single rhythms display features of amplitude (magnitude of peak to trough [nadir] difference), peak time (when the crest or maximum value occurs, usually given in clock hours or a reference point such as midsleep, or hours after light on); level or mean (average or midpoint value of the period) and waveform (graphic composite of peak time, period, slope of ascending and descending curves, and amplitude that depicts progression from any given point to the next point characterized by the same phase). The rhythmic quality of “phase” can be used to describe temporal relationships among two or more rhythms (Minor & Waterhouse, 1981). There may be reference to rhythms being “in phase” with one another. Internal synchronization of rhythms by the body’s timekeeping system is the usual condition. An example of such a relationship is that of circadian rhythms of rest (sleep)-activity and growth hormone in adults. Normally, growth hormone plasma levels rise sharply and peak early in the sleep portion of the sleep-activity cycle. When there is time displacement of one rhythm, there can be transient desynchronization among other rhythms. Some rhythms are able to adjust to environmentalcues more quickly than others. For example, when rest-activity,temperatureand urinary excretion of sodiumrhythms were compared in humans following a time shift, rest-activity adjusted more quickly then temperature, and temperature more quickly than urinary sodium excretion (Wever, 1979). When subjects experienced a six hour phase-advance (comparable to traveling west to east across six time zones), partial entrainment with environmental cues took -3 days for rest-activity rhythm; -4 days, temperature; and -7 days, urinary sodium excretion. More detailed presentations of rhythmic phenomena are available (Arendt,Minors & Waterhouse, 1989;Minors & Waterhouse, 1981; Moore-Ede, Sulzman & Fuller, 1982).
phase). The only difference was in the clock hour, or time, of exposure. In a study with five healthy males, Moore-Ede, Meguid, Fitzpatrick, Boyden & Ball (1978) infused the same dose of intravenous potassium at noon and at midnight. The plasma potassium concentration was found to be 40 percent higher following the midnight dose than after the noon dose. More recently, in patients with constant heparin infusion rates, activated partial thromboplastin and thrombin time values differed by as much as -50 percent and 60 percent respectively between specimens drawn at night and in the morning (Decousus et al., 1985). The role that rhythms play in health and disease has yet to be clearly determined; however, there is evidence to support the view that there are times within biological rhythmic cycles when an individual’s vulnerability and resistance fluctuate (Hrushesky, 1983; Reinberg, 1967). Conceptual Framework: Nursing ChronotherapeuticModel
To examine timing as a nursing therapeutic, a proposed nursing chronotherapeutic model has been adapted from work by Heitkemper and Shaver (1989) and presented in Figure 2.
0 Nur,infi.2rlt(inito:
* Alter c ti
