Effects of body position on thermal, cardiorespiratory and metabolic activity in low birth weight infants

Abstract

IntroductionCare takers have long noted that low birth weight (LBW) infants seem more comfortable when cared for in the prone position. They also spend more time in quiet sleep (1-3) and often have improvements in ventilation (4) as compared to supine position. These perceptions attracted further interest with the recognition that sudden infant death syndrome (SIDS) was related to prone body positioning during sleep [5][6][7][8][9][10] and decreased with the introduction of public health measures designed to reduce the incidence of prone sleeping [11]. The very fact that supine position protects against SIDS is counterintuitive, but nonetheless true. Numerous physiological differences related to body position have been reported [1][2][3][4][12][13][14][15][16][17][18][19][20][21][22][23] and reviewed [24], and several hypotheses have been formulated to explain how these differences might render infants more vulnerable to SIDS. One prominent hypothesis relates SIDS to relative increases in body temperature [25][26][27][28][29][30][31][32][33][34], thought to be caused by less efficient heat dissipation in the prone position.Evidence consistent with this hypothesis includes the observation that the victims of SIDS are commonly found in unusually warm environments, often feel warm and/or diaphoretic when discovered, and exhibit higher than expected rectal temperatures at examination or autopsy [32,33]. In addition, SIDS victims have often been wrapped tightly in clothing/bedding and/ or a history of a recent febrile illness is often elicited [34].A detailed study of the interactions among body position, sleep states, heat production, surface temperature profiles and surface temperature gradients, and cardiorespiratory activity in LBW infants may provide important information concerning physiological disturbances that predispose to SIDS, a condition to which LBW infants are especially susceptible as they grow to infancy [6]. The primary objective of this study was to test the hypothesis that despite lower metabolic rate (heat production), prone body position during sleep is associated with systematic Send correspondence to: Rakesh Sahni, M.D. Department of Pediatrics, College of Physicians and Surgeons, Columbia University, 630 W. 168th Street, New York, NY 10032, Tel. (212) 305-8500, Fax: (212) 305-8796, E-mail: E-mail: rs62@columbia.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptEarly Hum Dev. Author manuscript; available in PMC 2010 August 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript increases in ab...

Prone positioning decreases cardiac output and increases systemic vascular resistance in neonates

“…A slight increase in HR during prone sleep has been reported in preterm and low-birth weight infants 19,20 and term infants at 2-3 months of age. 21,22 However, keeping in line with our findings, term neonates at 2-4 weeks of age showed no significant change in HR when asleep in prone position.…”

Effects of prone and supine positioning on gastric residuals in preterm infants: A time series with cross-over study

“…and hypoxia, and better thoracoabdominal synchrony (Oliveira et al, 2009). Infants sleeping in the prone position also have higher surface temperatures and narrower central to peripheral temperature gradients (Ammari et al, 2009), and can sleep for longer, as well as experience fewer awakenings and arousals per hour, with a greater sleep efficiency (Myers et al, 1998). In previous studies, compared with preterm infants sleeping in the supine position, those in the prone position were found to exhibit earlier motor milestones (Davis et al, 1998), a lower energy expenditure, more gastric emptying and less gastro-oesophageal reflux (Blumenthal and Lealman, 1982;Ewer et al, 1999;Monterosso et al, 2002).…”

SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment

“…[54][55][56][57] The prone position also increases the risk of overheating by decreasing the rate of heat loss and increasing body temperature compared with infants sleeping supine. 58,59 Recent evidence suggests that prone sleeping alters the autonomic control of the infant cardiovascular system during sleep, particularly at 2 to 3 months of age, 60 and can result in decreased cerebral oxygenation. 61 The prone position places infants at high risk of SIDS (odds ratio [OR]: 2.3-13.1).…”