Infection-induced pathologic change in respiratory parameters in the young infant

While many aspects related to the etiology and pathogenesis of sudden infant death remain unclear, the ultimate trigger event appears to be an acute regulatory disturbance of the cardiorespiratory neurons of the reticular formation of the brain stem. Retrospective studies have demonstrated that SIDS often occurs after infection of the upper respiratory tract. We present the case history of a 10-week old infant, where the respiratory pattern demonstrated highly pathological alterations induced by a mild infection of the upper airways, as confirmed by oxycardiorespirography. Oxycardiorespirography provides continuous recording of the respiration (transthoracic impedance) extending over several hours during sleep and during the critical phase just before going to sleep and waking up in relation to heart rate, partial oxygen pressure (measured transcutaneously) and nasal flow. The presented infant is a premature infant delivered in the 34th week of gestation according to Dubowitz (artificial respiration for 7 days due to hyalin membrane syndrome stage II). During infection periodic breathing was found to be 19.3% with partly severe hypoxemia. The longest single episode of apnea was 30 seconds. On the average, 5 episodes of bradycardia occurred (less than 100/min/measuring hour). An OCRG investigation performed at the age of 5 weeks and after disappearance of the infection at the age of 12 weeks yielded normal findings. This permits the conclusion that in out patient an infection of the upper airways may have induced a pathologic respiratory pattern, which could be a major trigger mechanism for sudden infant death.