Response of Normal Infants to Inhaled Histamine

Abstract

The age at which nonspecific bronchial hyperresponsiveness (BHR) is first seen in humans is unknown, though both genetic and environmental factors have been implicated in its development. The current study aimed to establish whether BHR to histamine can be demonstrated in normal infants. Twelve infants, mean age of 7.8 months (range, 3 to 18 months), were studied. None had any history of a previous significant respiratory illness. Respiratory function was monitored using the maximal flow at function residual capacity (VmaxFRC) obtained with the forced expiratory flow-volume technique. Histamine was inhaled in doubling concentrations from 0.125 to 8 g.L-1. A greater than 30% fall in VmaxFRC was considered a response. All infants responded to histamine, the geometric mean concentration for their response being 1.4 g.L-1. Associated transient changes for the group were an increase in respiratory rate (p less than 0.02) and a fall in SaO2 (p less than 0.001). Forced expiratory flow-volume curves were concave in all infants after the last dose of histamine. We speculate that humans are born with "bronchial hyperresponsiveness" and that genetic or environmental factors determine which infants lose it thereafter.

Histamine challenges discriminate between symptomatic and asymptomatic children

“…In a study using oxygen saturation as a monitoring parameter, histamine challenges were performed in newborns and infants at 4 and 26 weeks, showing a marked decrease in Sa,O 2 in most of these healthy infants [40]. Similar results were obtained with histamine [37], methacholine [38] and cold, dry air challenges [36] in healthy infants.…”

Transcutaneous oxygen tension measurements during methacholine challenge of prematurity in infants with chronic lung disease

“…Abnormalities of airway resistance, dynamic pulmonary compliance, and lung volumes were reported. 21,22 Also, some techniques have been proposed for the evaluation of bronchial reactivity in infants by measuring the maximal flow at function residual capacity (VЈmaxFRC) 23 or the maximal expiratory flow-volume curves by forced compression of the thorax in babies with a face mask 24 or in intubated infants. 6 However, most of these techniques are complicated and performed relatively easily only in intubated infants.…”

Longitudinal assessment of airway responsiveness from 1 month to 18 years in the PIAF birth cohort

“…We recently published data from this birth cohort on lung function measurements from 1 month to 18 years [5]. We have previously shown that 1-month-old infants respond to histamine [6] and that the level of response is influenced by a family history of asthma and maternal smoking during pregnancy [7]. With follow-up of the cohort, we observed that the level of response in early infancy was the strongest early determinant of respiratory status at 6 years of age [8], but only the level of response in late infancy was linked to wheeze at 12 years [9].…”