The impact of temperature on neonatal resuscitation and temperature maintenance strategies C0009 NRP® Current Issues Seminar: Monumental Changes on the HorizonHenry C. Lee, MD, FAAPStanford 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

Convection EvaporationRadiation

ConductionPhotograph: "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?

• 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)

• 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

cpqcc.org

• Delivery Room Management Toolkit

Improving clinical practice through collaboration

Percent neonatal hypothermiaCPQCC Network 2006-2015

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…

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

Implementation Methods for Delivery Room Management: A Quality Improvement Comparison StudyLee H Pediatrics 2014; 134:e1378-1386

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 studiesComparison 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 temperature 23-35 oC + Radiant warmer + wrap body and head in plastic without drying + cap + thermal mattress)

Radiant warmer + Plastic wrap

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, B-NR, 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• 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.

ReferencesFor 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