The impact of temperature on neonatal resuscitation
and temperature maintenance strategies
C0009 NRP® Current Issues Seminar: Monumental
Changes on the Horizon
Henry C. Lee, MD, FAAP
Stanford University School of Medicine
(Palo Alto, CA)
• @hcleestanford
Faculty Disclosure Information
In the past 12 months, I have no relevant financial
relationships with the manufacturer(s) of any commercial
product(s) and/or provider(s) of commercial services
discussed in this CME activity.
I do not intend to discuss an unapproved/investigative
use of a commercial product/device in my presentation.
Outline
• Physiology and relationship of hypothermia to
preterm neonatal outcomes
• Practices to prevent hypothermia in preterm
neonates
• Implications for research and clinical practice
Physiology of thermal
regulation in neonates
Radiation
Convection
Evaporation
Conduction
Photograph: "HumanNewborn" by Ernest F - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons http://commons.wikimedia.org/wiki/File:HumanNewborn.JPG#/media/File:HumanNewborn.JPG
What is the normal (goal) temperature
for a preterm newborn infant?
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35.5–37.0 oC
36.0–37.0 oC
36.5–37.5 oC
36.0–37.9 oC
Temperature categories
(World Health Organization)
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Normal 36.5–37.5 oC
Mild hypothermia (cold stress) 36-36.5 oC
Moderate hypothermia 32–36 oC
Severe hypothermia < 32 oC
Hypothermia in very low birth weight infants:
distribution, risk factors and outcomes.
S Miller et al. Journal of Perinatology 2011; 31(S49-S56).
• California – 127 hospitals – 2006-2007
• 8,782 VLBW infants (birth weight < 1500 gm)
• Mean temperature 36.3oC
0.1% severe, 25.6% moderate, 30.5% mild hypothermia
Do you think that thermal regulation during
neonatal resuscitation matters for preterm infants?
• Yes - I think it is important as it may prevent
mortality and serious morbidities.
• Sort of – it might be helpful in some babies for
some minor morbidities.
• Not really sure – but probably doesn’t hurt to try.
• No – it probably doesn’t make any difference and
might even be harmful.
Association Between Admission Temperature and Mortality and
Major Morbidity in Preterm Infants Born at Fewer Than 33
Weeks’ Gestation. Y Lyu et al. JAMA Pediatrics 2015;169(4)
• Canadian Neonatal Network 2010-2012
• 29 NICUs
• Composite outcome: mortality, severe neurologic
injury, severe retinopathy, necrotizing
enterocolitis, bronchopulmonary dysplasia,
nosocomial infection
• 9,833 infants < 33 weeks
“optimal temperature” between 36.5 and 37.2°C
Improving clinical practice through collaboration
cpqcc.org
• Delivery Room Management Toolkit
Percent neonatal hypothermia
CPQCC Network 2006-2015
1
Infant Stays with Hypothermia, CPQCC Network, 2006-2015
40
Percent
30
20
10
0
2006
2007
2008
2009
2010
2011
2012
Birth Year
The band outlined in the chart is based on the unweighted lower and upper quartile across CPQCC centers.
The chart is preliminary for years with incomplete data (after 2014).
2013
2014
2015
VLBW Infants
• Ensure person assigned to monitor
temperature.
• Ensure resuscitation room ambient
temperature at least 26oC (79oF).
• Utilize chemically activated heat packs
• …plastic wrap, cap…
Implementation Methods for Delivery
Room Management: A Quality
Improvement Comparison Study
Lee H Pediatrics 2014; 134:e1378-1386
A reduction in intraventricular
hemorrhage (any grade) after
intervention in collaborative group
– odds ratio 0.80 (0.66-0.97)
No difference in severe IVH
ILCOR 2015
What is the optimal strategy for maintaining normal
temperature for a newborn preterm (< 32 weeks) infant?
• Radiant warmer and plastic wrap and cap
• Radiant warmer, plastic wrap, increased room
temperature
• Radiant warmer, plastic wrap, thermal mattress
• Radiant warmer, plastic wrap, warmed humidified
gas
ILCOR Review on warming adjunct studies
Comparison group 1
Group 2 (control)
Thermal mattress + Plastic wrap + Radiant warmer
Plastic wrap + Radiant warmer
Environmental temperature >=26 oC + Plastic wrap +
Radiant warmer
Plastic wrap + Radiant warmer
Heated and humidified gases + Plastic wrap + Radiant
warmer
Plastic wrap + Radiant warmer
Plastic cap + wrap + Radiant warmer
Plastic wrap + Radian warmer
Combination of interventions (Environmental
Radiant warmer + Plastic wrap
temperature 23-35 oC + Radiant warmer + wrap body and
head in plastic without drying + cap + thermal mattress)
Interventions to Maintain Newborn
Temperature in the Delivery Room
• The use of radiant warmers and plastic wrap with
a cap has improved but not eliminated the risk of
hypothermia in preterm infants in the delivery
room. Other strategies have been introduced,
which include increased room temperature,
thermal mattresses, and the use of warmed
humidified resuscitation gases.
Interventions to Maintain Newborn
Temperature in the Delivery Room
• Various combinations of these strategies may be
reasonable to prevent hypothermia in infants born at
less than 32 weeks of gestation (Class IIb, LOE B-R, BNR, C-LD). Compared with plastic wrap and radiant
warmer, the addition of a thermal mattress,66–70
warmed humidified gases,71,72 and increased room
temperature plus cap plus thermal mattress55,57,59,73
were all effective in reducing hypothermia.
Interventions to Maintain Newborn
Temperature in the Delivery Room
• For all the studies, hyperthermia was a
concern, but harm was not shown.
Hyperthermia (greater than 38.0°C) should be
avoided due to the potential associated risks
(Class III—Harm, LOE C-EO).
What is your priority on more research
/ implementation?
• Does prevention of hypothermia matter?
• How can we more effectively prevent
hypothermia?
• Are there potential harms in current methods to
prevent hypothermia?
• We know enough about this now; let’s move on!
Gaps in knowledge
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Do interventions decrease mortality?
Interventions to affect maternal temperature?
Rate of rewarming?
Most effective combination of strategies?
Harm from too much warming?
Will delayed cord clamping impact hypothermia
prevention strategies?
Changes You May Wish to Make in Practice
1. Evaluate rates of newborn hypothermia in
your unit.
2. Implement strategies to prevent hypothermia
and continue to monitor temperature.
References
For more information on this subject, see the following
publications:
Association Between Admission Temperature and Mortality and Major Morbidity
in Preterm Infants Born at Fewer Than 33 Weeks’ Gestation. Y Lyu et al. JAMA
Pediatrics 2015;169(4)
Hypothermia in very low birth weight infants: distribution, risk factors and
outcomes. S Miller et al. Journal of Perinatology 2011; 31(S49-S56)
Implementation Methods for Delivery Room Management: A Quality
Improvement Comparison Study. H Lee Pediatrics 2014; 134:e1378-1386