Old Standards Threaten Infant Life

The way that newborns are cared for in hospitals may see drastic revision after a startling study by the Duke University and the University of North Carolina’s Schools of Nursing shows that abdominal temperatures considered “normal” may be fatal to many infants. Neonates, in the first hours of life, often cannot regulate their body temperatures on their own and require external heating from nursing heaters called “servos”. The study concludes that “the traditional cut point of hypothermia (97.5 °F) may not be enough to minimize abnormalities in heart rate” and that because of this, there should be widespread reform to have nurses raise infant servo temperatures from the dangerously low 97.5 °F to between 98.24 °F and 98.42 °F. What may seem as a small difference in temperature (1.8 °F or 1°C) is the difference between life and death for preemies.

The study’s main focus was on the first 12 hours of life of extremely low birth weight infants (ELBW) in the Neonatal Intensive Care Unit (NICU). These infants weigh between 14.1 and 35.3 ounces, or from 0.88 to 2.21 pounds, and have dangerously thin skin making them susceptible to heat loss. ELBW infants are usually only 28 to 29 weeks gestational age. Prior research has established that hypothermia during the first 12 hours is especially harmful to premature infants and can lead to increased mortality and morbidity. A study by Deussen in 2007 reported that “Once the body temperature falls below 93.4 °F, cardiac output reduces due to bradycardia” (a heart rate under 100 bpm). Infants are unable to self-regulate body temperature until around week 32 gestational age. According to National Vital Statistics reports, there were roughly 33,000 ELBW infants born in 2003, which was about 0.8% of the total children born that year (Matthews and MacDorman).

Approximately 66% to 93% of ELBW infants are admitted to the NICU with hypothermic temperatures. Additionally, ELBW deaths accounted for almost 49% of all infant deaths in 2003. The U.S. Census Bureau found in 2006 that approximately 4.3 million babies were born in the U.S. According to a study by Dr. Bennett of the University of Washington School of Medicine, “Of the approximately 4 million annual live births in the United States, 7.5% are classified as low birth weight (LBW, < 5.51 lbs)

Reforms in nursing practice have been suggested by Dr. Knobel et al. and include the raising of incubator (servo) temperatures, using polyethylene bags for heat insulation, and the pre-heating of intravenous fluids, bedding, and delivery rooms. Anything that an infant may come into contact with during these critical first 12 hours must be warmed, even the air. Only 20% of 125 NICUs surveyed by Knobel in 2005 adhered to the American Academy of Pediatrics and American Heart Association recommendation to use polyethylene bags for heat loss prevention during delivery room resuscitation.

Admitted limitations of the study include a small sample size (10 ELBW infants) and an insufficient demographic. Reforms must be enacted quickly to help protect the 33,000 ELBW infants born each year.

By: Jim Allen

Original articles:

"Optimal Body Temperature in Transitional Extremely Low Birth Weight Infants Using Heart Rate and Temperature as Indicators." Journal of Obstetric Gynecologic and Neonatal Nursing 39.1 (2010): 3-14.

"Thermoregulation and Heat Loss Prevention After Birth and During Neonatal Intensive-Care Unit Stabilization of Extremely Low-Birthweight Infants." Journal of Obstetric, Gynecologic, & Neonatal Nursing 36.3 (2007): 280-287.

"Hyperthermia and hypothermia. Effects on the cardiovascular system." Anaesthesist, 56, 907-911.

Infant mortality statistics from the 2003 period linked birth/infant death dataset. National Vital Statistics Reports, 54, 1-30.