Interactions among peripheral perfusion, cardiac activity, oxygen saturation, thermal profile and body position in growing low birth weight infants

Abstract

Aims To investigate the correlation between the ‘perfusion index’ (PI) and other commonly used estimates of cutaneous blood flow [heart rate (HR), surface temperatures (ST) and central-to-peripheral thermal gradients (C-P grad)] and to use this new non-invasive tool to compare differences between prone and supine sleep position in low birth weight (LBW) infants. Methods Six-hour continuous recordings of pulse oximetry, cardiac activity and absolute ST from three sites (flank, forearm and leg), along with minute-to-minute assessment of behavioural states were performed in 31 LBW infants. Infants were randomly assigned to the prone or supine position for the first 3 h and then reversed for the second 3 h. PI data were correlated with HR and C-P grad, and compared across sleep positions during quiet sleep (QS) and active sleep (AS). Results Perfusion index correlated significantly with HR (r2 = 0.40) and flank-to-forearm thermal gradient (r2 = 0.28). In the prone position during QS, infants exhibited higher PI (3.7 ± 0.9 vs. 3.1 ± 0.7), HR (158.4 ± 8.9 vs. 154.1 ± 8.8 bpm), SpO2 (95.8 ± 2.6 vs. 95.2 ± 2.6%), flank (36.7 ± 0.4 vs. 36.5 ± 0.4°C), forearm (36.1 ± 0.6 vs. 35.5 ± 0.4°C) and leg (35.4 ± 0.7 vs. 34.7 ± 0.7°C) temperatures and narrower flank-to-forearm (0.6 ± 0.4 vs. 0.9 ± 0.3°C) and flank-to-leg (1.3 ± 0.6 vs. 1.8 ± 0.7°C) gradients, compared to those of the supine position. Similar differences were observed during AS. Conclusion Perfusion index is a good non-invasive estimate of tissue perfusion. Prone sleeping position is associated with a higher PI, possibly reflecting thermoregulatory adjustments in cardiovascular control. The effects of these position-related changes may have important implications for the increased risk for sudden infant death syndrome in prone position.

Cerebral Oxygenation in Preterm Infants

“…It is well established that prone sleeping is associated with an increase in temperature and peripheral vasodilation in infancy. 20,45,46 This reduction in peripheral vascular resistance stimulates a baroreflex-mediated increase in HR to maintain MAP. 19,45 This reflex response is consistent with our observations at 2 to 4 weeks and 5 to 6 months CA, where HR and temperature were increased in the prone position and MAP was maintained.…”

Pulse Oximetry Monitoring of Infants Who Require Prone Position For Sleep – Is There Evidence That This Practice Reduces SIDS?

“…The search strategy: 'infant AND prone AND pulse oximetry monitoring AND SIDS' yielded two clinical studies results. 30,31 Removing infant from the search but still including: 'pulse oximetry monitoring AND prone AND SIDS' yielded only the same two papers as before. 30,31 The second search: 'infant AND prone AND pulse oximet* AND SIDS' resulted in three papers.…”

“…30,31 Removing infant from the search but still including: 'pulse oximetry monitoring AND prone AND SIDS' yielded only the same two papers as before. 30,31 The second search: 'infant AND prone AND pulse oximet* AND SIDS' resulted in three papers. 30,32,33 Removing infant from the search for 'prone AND pulse oximet* AND SIDS' yielded the same three results.…”

“…30,31 The second search: 'infant AND prone AND pulse oximet* AND SIDS' resulted in three papers. 30,32,33 Removing infant from the search for 'prone AND pulse oximet* AND SIDS' yielded the same three results. 30,32,33 Expanding the search to the general PubMed database (not limited to the Clinical Queries section) with the limit of infant (age birth -23 months) and the search strategy: 'pulse oximetry AND prone AND SIDS' yielded five papers.…”

“…30,32,33 Expanding the search to the general PubMed database (not limited to the Clinical Queries section) with the limit of infant (age birth -23 months) and the search strategy: 'pulse oximetry AND prone AND SIDS' yielded five papers. 30,31,[33][34][35] In summary, a total of six unique papers were identified [30][31][32][33][34][35] from the literature search which could possibly address the question.…”