Nurse Faculty Scholars - Neonatal Health

Thermoregulation and thermography in neonatal physiology and disease

kdeming — Tue, 01 Nov 2016 00:01:26 +0000

Published Date:

Tue, 2011-05-17 (All day)

Thermoregulation, or control of body temperature, has been studied as a fundamental physiological parameter defining health and disease for centuries (Ring, 2007; Ring, McEvoy, Jung, Zuber, & Machin, 2010). Multiple techniques have been used to assess thermoregulation in infants and adults, including the recent development of infrared thermography. Thermography can measure and visualize skin surface thermal patterns in the study of body temperature, and researchers have used this novel methodology to study cancer, peripheral vascular disease, trauma, and wound management (Kateb, Yamamoto, Yu, Grundfest, & Gruen, 2009; Katz et al., 2008; Mital & Scott, 2007; Nakanishi & Imai-Matsumura, 2008). We have recently developed methods to use infrared thermography to measure body temperature in neonates during their first month of life to examine relationships between control of body temperature and perfusion, as well as association between thermoregulation and clinical disease processes such as necrotizing enterocolitis. This paper will review methods for using infrared thermography, current research using this measurement tool, and use in our current neonatal research.

Exploring the association between pain intensity and facial display in term newborns

lsharp — Mon, 14 Mar 2011 13:04:26 +0000

Published Date:

Fri, 2011-01-14 (All day)

BACKGROUND: Facial expression is widely used to judge pain in neonates. However, little is known about the relationship between intensity of the painful stimulus and the nature of the expression in term neonates. OBJECTIVES: To describe differences in the movement of key facial areas between two groups of term neonates experiencing painful stimuli of different intensities. METHODS: Video recordings from two previous studies were used to select study subjects. Four term neonates undergoing circumcision without analgesia were compared with four similar male term neonates undergoing a routine heel stick. Facial movements were measured with a computer using a previously developed 'point-pair' system that focuses on movement in areas implicated in neonatal pain expression. Measurements were expressed in pixels, standardized to percentage of individual infant face width. RESULTS: Point pairs measuring eyebrow and eye movement were similar, as was the sum of change across the face (41.15 in the circumcision group versus 40.33 in the heel stick group). Point pair 4 (horizontal change of the mouth) was higher for the heel stick group at 9.09 versus 3.93 for the circumcision group, while point pair 5 (vertical change of the mouth) was higher for the circumcision group (23.32) than for the heel stick group (15.53). CONCLUSION: Little difference was noted in eye and eyebrow movement between pain intensities. The mouth opened wider (vertically) in neonates experiencing the higher pain stimulus. Qualitative differences in neonatal facial expression to pain intensity may exist, and the mouth may be an area in which to detect them. Further study of the generalizability of these findings is needed.

Heat loss prevention in the delivery room for preterm infants: a national survey of newborn intensive care units.

nfs — Tue, 28 Sep 2010 14:40:12 +0000

Published Date:

Mon, 2005-08-01 (All day)

OBJECTIVE: To describe current NICU practices with respect to wrapping preterm infants to prevent heat loss in the delivery room.

STUDY DESIGN: E-mail survey of neonatologists from national registry using a web-based survey tool.

RESULTS: Of 411 e-mails successfully delivered, 125 (30%) responded. Most (87%) represented level III NICUs. Almost one-fifth of respondents (20%) use occlusive material instead of drying preterms in the delivery room. Considerable variation exists regarding choice of wrap and duration of use. Few adverse events were reported.

CONCLUSION: "In all" was added -This implies 20% of all NICU's changed practice, 20% of level III NICUs responding have changed delivery room resuscitation practices rapidly in response to new evidence. No "gold" standard exists nationally and there is considerable variation in practice. Neonatal resuscitation guidelines for premature infants should include recommendations regarding choice occlusive wrap and application techniques.

BACKGROUND: Hypothermia incurred during delivery room resuscitation continues to cause morbidity in infants <29 weeks gestation. Three recent trials have shown that wrapping such infants instead of drying prevents heat loss, resulting in higher infant temperatures at Newborn Intensive Care Unit (NICU) admission.
OBJECTIVE: To describe current NICU practices with respect to wrapping preterm infants to prevent heat loss in the delivery room.
STUDY DESIGN: E-mail survey of neonatologists from national registry using a web-based survey tool.

Heat Loss Prevention for Preterm Infants in the Delivery Room

nfs — Tue, 28 Sep 2010 14:37:28 +0000

Published Date:

Sat, 2005-01-01 (All day)

OBJECTIVE: Preterm infants are prone to hypothermia immediately following birth. Among other factors, excessive evaporative heat loss and the relatively cool ambient temperature of the delivery room may be important contributors. Most infants <29 weeks gestation had temperatures <36.4°C on admission to our neonatal unit (NICU). Therefore we conducted a randomized, controlled trial to evaluate the effect of placing these infants in polyurethane bags in the delivery room to prevent heat loss and reduce the occurrence of hypothermia on admission to the NICU. METHODS: After parental consent was obtained, infants expected to be <29 weeks gestation were randomized to intervention or control groups just prior to their birth. Infants randomized to the intervention group were placed in polyurethane bags up to their necks immediately after delivery before being dried. They were then resuscitated per NRP guidelines, covered with warm blankets, and transported to the NICU, where the bags were removed and rectal temperatures were recorded. Control infants were resuscitated, covered with warm blankets, and transported without being placed in polyurethane bags. Delivery room temperatures were recorded so this potentially confounding variable could be assessed. RESULTS: Intervention patients were less likely than control patients to have temperature < 36.4°C on admission , 44 vs 70% (p<0.01) and the intervention group had a higher mean admission temperature, 36.5°C vs 36.0°C (p<0.003). This effect remained significant (p<0.0001) when delivery room temperature was controlled in analysis. Warmer delivery room temperatures (26°C) were associated with higher admission temperatures in both intervention and control infants, but only the subgroup of intervention patients born in warmer delivery rooms had a mean admission temperature >36.4°C. CONCLUSIONS: Placing infants <29 weeks gestation in polyurethane bags in the delivery room reduced the occurrence of hypothermia and increased their NICU admission temperatures. Maintaining warmer delivery rooms helped but was insufficient in preventing hypothermia in most of these vulnerable patients without the adjunctive use of the polyurethane bags.

Extremely low birth weight preterm infants lack vasomotor response in relationship to cold body temperatures at birthELBW infants lack vasomotor response in cold body

nfs — Mon, 27 Sep 2010 12:20:46 +0000

Published Date:

Tue, 2009-12-01 (All day)

Study Objective: This study evaluated peripheral vasoconstriction in extremely low birth weight (ELBW) infants when body temperature decreased during the first 12 h of life. Study Design: An exploratory, within-subjects design with 10 ELBW infants. Abdominal and foot temperatures were measured every minute. Peripheral vasoconstriction (abdominal>peripheral temperature by 2 °C) and abdominal–peripheral temperature difference were also evaluated. Results:Abdominal and peripheral temperatures were significantly correlated within each infant. One 880 g infant exhibited isolated peripheral vasoconstriction; a 960-g infant had abdominal temperatures >1 °C higher than peripheral temperatures. Eight smaller infants exhibited no peripheral vasoconstriction and spent most of their observations with peripheral greater than abdominal temperatures. In eight infants, mean temperature difference was significantly higher when abdominal temperature was <36.5 °C. Conclusion: Most ELBW infants did not exhibit peripheral vasoconstriction during their first 12 h of life, despite low temperatures. ELBW infants’ vasomotor control may be immature during this period.

Study Objective: This study evaluated peripheral vasoconstriction in extremely low birth weight (ELBW) infants when body temperature decreased during the first 12 h of life.

Thyroid hormone levels in term and preterm neonates

nfs — Mon, 27 Sep 2010 12:17:06 +0000

Published Date:

Wed, 2007-08-01 (All day)

Screening for thyroid hormone levels in the first week of life is extremely important to identify infants with Congenital Hypothyroidism. Worldwide neonatal screening programs have been successful in decreasing childhood mental retardation related to CH by early detection and treatment. To successfully screen for CH, nurses must understand how to draw blood that will yield valid results on the metabolic screening filter paper. It is also important for the nurse to understand that thyroid levels are normally decreased in preterm infants and that regular follow-up of those low thyroid levels is crucial because levels may return to normal and eventual treatment is necessary. Early follow-up testing and treatment are essential. A thyroid scan or ultrasonography is optional and decided on by evaluating the risk-benefit ratio.

Screening for thyroid hormone levels in the first week of life is extremely important to identify infants with CH. Worldwide neonatal screening programs have been successful in decreasing childhood mental retardation related to CH by early detection and treatment. To successfully screen for CH, nurses must understand how to draw blood that will yield valid results on the metabolic screening filter paper.

Peripheral Vasoconstriction in Transitional ELBW Infants

nfs — Mon, 27 Sep 2010 12:11:15 +0000

Published Date:

Tue, 2008-07-01 (All day)

Objective: This study evaluated the ability of ELBW infants weighing 400–1000 grams to exhibit peripheral vasoconstriction when body temperatures decreased.

Design/Methods: A within subject, multiple case design was used to explore the relationships between body temperature and peripheral vasoconstriction in 10 ELBW infants over their first 12 hours in the NICU. Abdominal temperature (AT) and peripheral temperature (PT) were measured in 1-min. intervals. Peripheral vasoconstriction is defined as AT 2°C above PT as established by Lyon et al. Each infant was evaluated for length of time spent with peripheral vasoconstriction.

Results: PT and AT were significantly correlated in each infant. One infant (BW: 880 gms) exhibited peripheral vasoconstriction and one infant (BW 960 gms) had AT 1°C greater than PT. Eight infants (BW: 510–720 gms) did not exhibit peripheral vasoconstriction. Seven infants spent at least 15% of their observations with PT > AT and these infants were most likely to have PT 1–2°C>AT. The peripheral-abdominal temperature difference increased during stressful procedures in some infants.

Conclusions: ELBW infants have little ability to vasoconstrict in response to NST. PT were more often > AT and this difference often increased during stressful clinical events. Vasomotor control appears immature at birth in infants <800 grams.

Background: ELBW infants are vulnerable to cold stress during the transition from delivery room to intensive care. Infants produce heat by non-shivering thermogenesis (NST) and should exhibit peripheral vasoconstriction when cold, but little empirical evidence confirms that ELBW infants are capable of peripheral vasoconstriction.
Objective: This study evaluated the ability of ELBW infants weighing 400–1000 grams to exhibit peripheral vasoconstriction when body temperatures decreased.

Optimal Body Temperature in Transitional Extremely Low Birth Weight Infants Using Heart Rate and Temperature as Indicators

nfs — Mon, 27 Sep 2010 12:06:06 +0000

Published Date:

Thu, 2010-01-07 (All day)

Objective: To explore body temperature in relationship to heart rate in extremely low birth weight (ELBW) infants during their first 12 hours to help identify the ideal set point for incubator control of body temperature. Design: Within subject, multiple-case design. Setting: A tertiary neonatal intensive care unit (NICU) in North Carolina. Participants: Ten infants born at fewer than 29 weeks gestation and weighing 400 to 1,000 g. Methods: Heart rate and abdominal body temperature were measured at 1-minute intervals for 12 hours. Heart rates were considered normal if they were between the 25th and 75th percentile for each infant. Results: Abdominal temperatures were low throughout the 12-hour study period (mean 35.17-36.68 1C). Seven of 10 infants had significant correlations between abdominal temperature and heart rate. Heart rates above the 75th percentile were associated with low and high abdominal temperatures; heart rates less than the 25th percentile were associated with very low abdominal temperatures. The extent to which abdominal temperature was abnormally low was related to the extent to which the heart rate trended away from normal in 6 of the 10 infants. Optimal temperature control point that maximized normal heart rate observations for each infant was between 36.8 1C and 37 1C. Conclusions: Hypothermia was associated with abnormal heart rates in transitional ELBW infants. We suggest nurses set incubator servo between 36.8 1C and 36.9 1C to optimally control body temperature for ELBW infants.

Thermoregulation and Heat Loss Prevention After Birth and During Neonatal Intensive-Care Unit Stabilization of Extremely Low-Birthweight Infants

nfs — Mon, 27 Sep 2010 12:01:26 +0000

Published Date:

Mon, 2007-05-07 (All day)

Extremely low-birthweight infants have inefficient thermoregulation due to immaturity and may exhibit cold body temperatures after birth and during their first 12 hours of life. Hypothermia in these infants can lead to increased morbidity and mortality. Anecdotal notes made during our recent study revealed extremely low-birthweight infants’ temperatures decreased with caregiver procedures such as umbilical line insertion, intubations, obtaining chest x-rays, manipulating intravenous lines, repositioning, suctioning, and taking vital signs during the first 12 hours of life. Therefore, nursing interventions should be undertaken to prevent heat loss during these caregiver procedures. Nurses can improve the thermal environment for extremely low-birthweight infants by prewarming the delivery room and placing the infant in a plastic bag up to the neck during delivery room stabilization to prevent heat loss.