Increased inspiratory effort in infants with a history of apparent life-threatening event.

UNLABELLED: The objective of this study was to compare the results of polysomnography between infants with a history of apparent life-threatening event (ALTE) and controls. In this case-control study, 40 full-term ALTE infants, aged 2-36 wk at the time of the event, were compared with 40 age- and sex-matched randomly selected controls. SaO2, tcpO2, tcpCO2, heart rate (HR), vector of rib cage and abdominal respiratory movements (phase angle, as an index of inspiratory effort) were recorded during natural nocturnal active and quiet sleep (AS, QS). SaO2, tcpO2, tcpCO2 were similar in ALTE and controls in both sleep states. Phase angle was increased in ALTE infants in both AS (59+/-46 vs 26+/-17 degrees) and QS (53+/-46 vs 18+/-14, p < 0.001). Eleven ALTE infants (27.5%) experienced SaO2 < 90%, with a mean decrease in SaO2 to 86+/-1.6% (mean +/- SD), compared with 10% for controls (p=0.003). In eight ALTE infants, SaO2 values <90% were linked to thoracoabdominal asynchrony. SaO2 < 90% in conjunction with HR <100 bpm were detected in three ALTE infants and one control. Periodic breathing was observed in 45% of ALTE infants and 40% of controls.

CONCLUSION

The mean values of oxygen saturation, tcpO2 and carbon dioxide levels in ALTE infants are comparable with those of healthy controls but the ALTE infants exhibit more hypoxaemic episodes and increased inspiratory effort during sleep.