PATTERNS OF HYPOXEMIA IN INFANTS WITH RESPIRATORY SYNCYTIAL VIRUS(RSV) BRONCHIOLITIS AND PNEUMONIA, MEASURED BY EAR OXIMETRY

The degree and duration of hypoxemia in babies with RSV has not been studied. We used an ear oximeter to measure dally the arterial satuation(% Sat)on 32 infants consecutively admitted with RSV bronchiolitis and pneumonia; median age 2 months. Oximetry readings compared to simultaneous arterial gases gave a correlation coefficient of 0.95, and 0.7 compared to capillary gases. On admission these infants' mean % Sat was 86%(pO2=53 mm Hg), range 75-95%(pO241-75). The lowest mean value was not until day 3 and was 85%(pO251) with a range of 53-96%(pO228-87). The severity of hypoxemia fluctuated in any given day and was prolonged. At discharge the mean % Sat=90%(pO260) range 83-98% (pO247-113); only 3 infants had values >93%(or >pO266). Mean % Sat of 9 infants 3-7 weeks after discharge was 96%(pO287), range 93-98%(pO266-113). Clinical detection of hypoxemia was difficult. Marked hypoxemia existed without cyanosis. However, severity of hypoxemia correlated with cyanosis, respiratory rate, younger age and % bands. No correlation existed with total WBC, PMNs, nor clinical severity judged by retraction and lethargy. Thus, RSV hypoxemia may be severe, prolonged, and clinically occult. Ear oximetry is a valuable and non-invasive technic in the management of infants with RSV lower respiratory tract disease.