Transcutaneous and arterial blood gas monitoring during acute asthmatic symptoms in older children.

Abstract

The relationship between transcutaneous and arterial blood gases was investigated in 14 children with asthmatic symptoms, aged 7-15 years, before and after the inhalation of salbutamol. The degree of bronchial obstruction was assessed by forced expiratory volume in one second (FEV1) and maximum expiratory flow when 25% of FVC remained to be expelled (MEF25). On average the transcutaneous PO2 (tcPO2) was 1.3 kPa (range, 2.6-0 kPa) lower and the transcutaneous PCO2 was 0.6 kPa (range, 0-1.5 kPa) higher than the corresponding arterial values (P less than 0.01). The difference between arterial and transcutaneous PO2 was the same over the whole range of values studied (7.5-14 kPa). After the inhalation of salbutamol, the relationship between transcutaneous and arterial blood gases was not significantly changed. Changes in transcutaneous PO2 correlated to changes in MEF25 (P less than 0.05), indicating a common denominator, probably the conditions in the peripheral airways. We conclude that the close relationship between transcutaneous and arterial blood gases, even after the inhalation of a beta-2 agonist, indicates that the transcutaneous technique can be used for monitoring acute bronchial obstruction and for evaluating the effects of treatment in children of different ages.