Transcutaneous oxygen tension measurements during methacholine challenge of prematurity in infants with chronic lung disease.
Chronic lung disease (CLD) of prematurity may be caused by a number of insults during mechanical ventilation, including barotrauma and hyperoxia. To evaluate bronchial hyperresponsiveness (BHR) in infants with CLD of prematurity, we measured changes in transcutaneous oxygen tensions (tcPO2) during methacholine inhalation challenge. Twelve infants with CLD and 22 age-matched children without respiratory diseases were enrolled in this study (ages--5 to 36 months; mean age--16.2 months). Serial doses of methacholine were doubled until a 10% decrease in tcPO2 from baseline was reached. The cumulative dose of methacholine inhaled by the time tcPO2 had been reached (Dmin-PO2) was considered to represent the dose at which reactivity to methacholine (RO2meth) had occurred. In the CLD group, Dmin-PO2 (3.50 +/- 0.1 log x milli-units) was significantly lower than in the preterm control infant group (4.31 +/- 0.2 log x milli-units) and the term infant group (4.21 +/- 0.1 log x milli-units) (P = 0.004, P < 0.001). Dmin-PO2 in the preterm control infant group was not significantly different than in the term infant group (P > 0.5). These results suggest that infants who require additional therapeutic oxygen and mechanical ventilation during the early months of life are at risk of developing early-onset, long-lasting respiratory disease that is related to an acquired BHR.
Mochizuki
H
H
Saku Central Hospital, Department of Allergy, Usuda, Nagano, Japan.
Ohki
Y
Y
Nako
Y
Y
Morikawa
A
A
D016535:Bronchial Hyperreactivity / Q000175:diagnosis*; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D002908:Chronic Disease; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000503:physiopathology*; D016210:Methacholine Chloride; D010100:Oxygen / Q000032:analysis*; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology*
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D010100:Oxygen