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Effects of sleeping position on development of infant cardiovascular control
S R Yiallourou1, A M Walker, R S C Horne
1Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia.
Insights
Prone sleeping may impair infant blood pressure regulation during sleep, especially at 2-3 months, increasing SIDS risk. Heart rate compensation is insufficient at this critical age, potentially leading to circulatory failure.
Area of Science:
- Neonatal physiology
- Cardiovascular regulation
- Sudden Infant Death Syndrome (SIDS) research
Background:
- Sudden Infant Death Syndrome (SIDS) is linked to prone sleeping.
- Circulatory failure is a hypothesized factor in SIDS.
- Understanding infant cardiovascular responses to sleep position is crucial.
Purpose of the Study:
- To investigate the impact of prone sleeping on heart rate (HR) and blood pressure (BP) control in infants.
- To assess cardiovascular adjustments during sleep in supine versus prone positions.
- To determine if these effects change during the first 6 months of life.
Main Methods:
- Longitudinal study of 20 term infants from 2-4 weeks to 5-6 months.
- Daytime polysomnography utilized to monitor sleep states (quiet sleep and active sleep).
- Photoplethysmographic cuff measured arterial pressure (MAP, SAP, DAP) and HR in supine and prone positions.
Main Results:
- Blood pressure was lower in quiet sleep compared to active sleep across all ages and positions.
- At 2-3 months, prone sleeping in quiet sleep led to decreased systolic arterial pressure and increased heart rate.
- Postnatal age influenced blood pressure, with lower MAP and DAP observed at 2-3 months.
Conclusions:
- Infant blood pressure is modulated by sleep state and sleeping position.
- Prone sleeping may cause a blood pressure drop, compensated by heart rate increases at 2-4 weeks and 5-6 months.
- This compensation is absent at 2-3 months, coinciding with peak SIDS risk, potentially increasing circulatory failure risk.
Objective:
Sudden Infant Death Syndrome (SIDS) is associated with prone sleeping, and circulatory failure has been hypothesised to be a factor in the fatal event. We aimed to determine the effect of prone sleeping on heart rate (HR) and blood pressure (BP) control over the first 6 months of life.
Subjects:
Term infants (n = 20) were studied longitudinally at 2-4 weeks, 2-3 months and 5-6 months with daytime polysomnography.
Main Outcome Measures:
A photoplethysmographic cuff (Finometer, FMS, Finapres Medical Systems, Amsterdam, The Netherlands) on the infant's wrist measured mean, systolic, and diastolic arterial pressure (MAP, SAP, DAP) and HR during quiet sleep (QS) and active sleep (AS) in both the supine and prone positions.
Results:
BP in QS was lower compared to AS (by 3-9 mmHg) in both positions and at all three ages (p<0.05). At 2-3 months, a change from supine to prone in QS induced a fall in SAP (6 mmHg, p<0.05) and a rise in HR (4 bpm, p<0.05). An overall effect of postnatal age (PNA) on BP was identified (ANOVA) with MAP and DAP consistently averaging less (by 1-9 mmHg) at 2-3 months in both sleep states and sleeping positions compared with both other ages.
Conclusions:
Infant BP is modified by sleep state and sleeping position. A tendency for BP to fall in the prone position appears to be prevented by elevated HR at 2-4 weeks and 5-6 months, but not at 2-3 months, coincident with the age of greatest risk for SIDS. An uncompensated fall in BP in the prone position at this age could increase the possibility of circulatory failure and SIDS in vulnerable infants.
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