Influence of breathing pattern on transcutaneous oxygen and carbon dioxide tension during histamine provocation in children with bronchial asthma

Abstract

The influence of the breathing pattern on transcutaneous blood gases was evaluated in 18 boys and 8 girls 7-18 years of age, with bronchial asthma, during bronchial provocation with histamine-HCl. Transcutaneous oxygen tension (tcPO2), carbon dioxide tension (tcPCO2) and the breathing pattern assessed by the transthoracic impedance technique were continuously monitored during the provocation. At reaction, when the fall in the forced expiratory volume in 1 s (FEV1) was 20% or more, the tcPO2 fell by 15% or more below the baseline in 22/26 and by 20% or more in 14/26 children. In some children, a marked fall in the tcPO2 was already noted after the saline inhalation and the first histamine dose steps without simultaneous changes in the FEV1. This early fall in the tcPO2 correlated to changes in the breathing pattern and was interpreted as a sign of compensatory hypoventilation secondary to the hyperventilation observed during the inhalations. We conclude that transcutaneous oxygen tension can be used as an indicator of a bronchial reaction during bronchial provocation tests in children only if one takes account of the fact that the breathing pattern during the inhalation of the challenge compound per se has an effect on the oxygen tension.

Histamine provocation in young, awake children with bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction

“…Whether these conditions existed or not could not be concluded clearly from the data presented in the studies in question. A fall of 20% or more in tcPO 2 has been found to occur at about the same dose stage of histamine, which causes a fall of 20% or more in FEV 1 in older children (6,9). The same fall in the tcPO 2 also appeared to be a safe cut-off point for a significant bronchial reaction in young children, as judged by the fact that no child experienced any harmful symptoms during the provocation procedure in the present study.…”

“…ACTA PAEDIATR 88 (1999) indirect measurement of airway function both during acute asthmatic symptoms (15,16) and during bronchial provocation in children (1)(2)(3)(4)(5)(6)(7). When using a fall in oxygenation as the only measurement of the airway response, however, one must take account of the fact that variations in the breathing pattern per se may affect the oxygenation (9). This is especially important during investigations in young, awake children, where variations in the breathing pattern may cause significant changes in the baseline tcPO 2 values (10).…”

“…This is especially important during investigations in young, awake children, where variations in the breathing pattern may cause significant changes in the baseline tcPO 2 values (10). Furthermore, hyperventilation during the inhalation of saline or histamine may result in a compensatory period of hypoventilation after the inhalation which may lead per se to a fall in oxygenation (9). In order to avoid such "early, false-positive" reactions, children with evident signs of hyperventilation verified by a decrease in tcPCO 2 and/or a fall in oxygen tension of more than 15% after the inhalation of NaCl were considered to have too "unstable" a breathing pattern for reliable measurements during the provocation.…”

“…However, only one previous study has so far been reported in which a fall in oxygenation was the only indicator of a significant bronchial reaction during bronchial provocation in young, awake children (8). The reason for the hesitation about using the tcPO 2 as the only indicator of a bronchial reaction may be explained by methodological problems, such as difficulty creating "stable" baseline values in the transcutaneous blood gases due to the fact that the oxygenation may be affected by changes in the breathing pattern (9) and by the state of activity in the awake, young child (10).…”

Postoperative assessment of free skin flap viability by transcutaneous pO2 measurement using dynamic phosphorescence imaging

“…Due to pre-existing diseases like diabetic disease, venous or arterial hypertension, pulmonal diseases or different anatomic conditions [23][24][25][26] the mean tissue oxygen tension of each patient differs a lot (e.g. Pat.…”