Abstract
Whereas a normal infant should arouse from sleep and resume breathing in response to the hypoxic (↓O2) and hypercarbic (↑CO2) stimuli associated with sleep apnea, N-M SIDS infants are less likely to arouse in response to ↓O2 or↑CO2 stimuli (Hunt, ARRD 121:290, 1980). ↑CO2 and ↓O2 arousal responses (AR) were measured in 22 normal and 11 N-M SIDS infants at 7.3 ± 3.3 (SD) and 9.3 ± 4.4 weeks of age, respectively (NS). AR were performed during natural sleep by altering inspired gas concentration (FICO2, FIO2) in a headhood; end-tidal CO2 (PACO2), tcPO2, ECG and heart rate, thoracic and abdominal circumference (strain gauges) were continuously recorded. For each ↑CO2 AR, step increases in FICO2 were made at 5-minute intervals until arousal occurred. For each ↓O2 AR, step decreases in FIO2 were made at 3-minute intervals until arousal occurred or until FIO2=0.15. Behavioral criteria for arousal were agitation and eye opening and/or crying. AR to ↑ PCO2 occurred at a significantly higher mean PACO2 in N-M SIDS than control infants, 55 ± 3 (SD) versus 49 ± 6, respectively (p<.05). AR to ↓O2 occurred in 70% of normal versus only 9% of N-M SIDS infants (p < .01). In the one N-M SIDS infant in whom an ↓O2 AR occurred,↑CO2 AR did not occur until PACO2=61 mmHg. In summary, the level of respiratory chemostimulation required to produce an AR from sleep is significantly greater in N-M SIDS than in normal infants. Deficient AR may prevent N-M SIDS infants from responding appropriately to apneic asphyxia.
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Mcculloch, K., Brouillette, R., Guzzetta, A. et al. 1698 ABNORMAL HYPERCARBIC AND HYPOXIC AROUSAL RESPONSES IN NEAR-MISS (N-M) SIDS. Pediatr Res 15 (Suppl 4), 726 (1981). https://doi.org/10.1203/00006450-198104001-01717
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DOI: https://doi.org/10.1203/00006450-198104001-01717