Comparison of 2‐channel and 4‐channel pneumograms

To determine whether the addition of air flow and O₂ saturation (Sa O 2) channels improves sensitivity of the pneumogram in identifying cardiorespiratory pattern abnormalities, 2‐and 4‐channel pneumograms (PG‐2 and PG‐4) were simultaneously recorded in 91 consecutive infants. Forty‐one infants (45%) had cardiorespiratory symptoms, and 50 were asymptomatic. Pneumograms were considered abnormal for any of the following: apnea ≧ 20 seconds, heart rate < 80 bpm for gt; 5 seconds in preterm and < 60 bpm in full‐term infants (bradycardia), shorter apnea with bradycardia or desaturation, periodic breathing gt; 7% of total sleep time in preterm and gt; 4% in full‐term infants, or Sa O 2 < 85% for gt; 5 seconds. Both recordings were normal in 72% of infants and abnormal in 24%. In only 4% were the PG‐4 abnormal when the PG‐2 were normal, in all instances due to minimum Sa O 2 levels of 77–84% for 5–19 seconds associated with central apnea of intermediate duration (three infants) or with mixed apnea. The difference in frequency of abnormal results between the PG‐2 and PG‐4 recordings was not statistically significant (X²). In conclusion, although PG‐4 do increase the scope of physiological information obtained in infants with cardiorespiratory events, this short‐term study does not establish whether this increase results in any long‐term benefits. Further, at least in this number and these types of at‐risk infants, PG‐4 do not improve the sensitivity of cardiorespiratory recordings for detecting abnormalities. © 1992 Wiley‐Liss, Inc.