Page 543 - Encyclopedia of Nursing Research

510 n THERMAL BALANCE

Situations that promote heat loss or inter- linked disorder occurring when suscepti-
fere with heat generation put patients at risk ble persons receive anesthetic agents, led
T for hypothermia. The neonatal nurse must be to closer surveillance of perioperative body
extremely sensitive to the low-birthweight temperature. This precaution reduced mor-
infant’s need for external heat source. unable tality from hyperthermia in this uncommon
to shiver, the neonate expends oxygen to condition, but also brought to awareness the
metabolize brown fat and can easily become high incidence of low body temperatures in
hypoxic from cold exposure. Declining met- most surgical patients. Increased survival of
abolic and vasomotor activity makes older preterm infants in the 1970s created increased
persons particularly susceptible to heat loss concern for thermal balance of vulnerable
during surgery, trauma, or outdoor exposure. infants. Studies of environmental influences,
Hypothermic states can destabilize thermo- warming devices, and skin-to-skin contact
regulatory function further, eventually lead- were made possible by sophisticated contin-
ing to death. uous skin temperature monitors.
Since early times, fever patterns have Temperature measurement issues con-
provided a key indicator for detecting the tinue to dominate clinical nursing research,
onset and progress of infections. Concern stimulated by the commercial development of
that high temperatures could cause irrevers- new technologies in thermometers. Erickson
ible brain damage led nurses to routinely cool (1999) and McKenzie and Erickson (1996)
patients with rising body temperature using were among the first to compare oral, skin,
ice packs, cooling sponge baths, or circulating rectal, and tympanic membrane measure-
fans, regardless of the temperature elevation’s ment sites as well as methods of thermome-
cause. In the 1970s, nurses used conductive try in children and adults. Findings reassure
cooling blankets with refrigerated circulat- nurses that oral measurement provided reli-
ing coolant to appropriately treat refractory able intermittent thermal assessment in afe-
hyperthermia in which thermoregulatory brile patients. Newer research studies have
cooling responses are impaired. However, reaffirmed this in community-dwelling older
in treating fever, in which thermoregulation adults (Lu, Dai, & Yen, 2009). Although place-
remains intact, sharp gradients between skin ment site and method of insertion yield statis-
and core temperatures stimulated vigorous tically significant differences, they are of less
and distressful shivering. Interventions to importance clinically. Erickson’s work was
prevent shivering were among the earliest to set apart from other contemporary studies by
be tested by nurses. Interest in and awareness her appropriate statistical treatment beyond
of temperature variations became more acute simple correlations and by meaningful inter-
among nurse researchers when advanced pretation of device reliability, accuracy, and
technology in thermometry was introduced linearity. In the past decade, nurse research-
to clinical settings. Hemodynamic monitor- ers began drawing inferences from observed
ing systems with thermistor probes first made relationships between thermal changes and
pulmonary artery temperature measurement other variables. gradients between skin
possible in critical care settings in the 1970s. and core temperatures initiate thermoreg-
The availability of clinically made bladder, ulatory responses (see entry on Shivering).
tympanic membrane, and skin temperature Studies have shown the importance of ther-
probes led to numerous studies of gradients mal gradients and rate of cooling in initiating
between body regions and measurement shivering in a comparison of cooling blan-
sites. Variation in quality and precision of ket temperatures (Caruso, Hadley, Shukla,
instruments made studies of reliability and Frame, & Khoury, 1992; Sund-Levander &
accuracy important. Recognition of malig- Wahren, 2000). Nursing research has also
nant hyperthermia, a rare but lethal genetically tested methods to alleviate adverse effects of