The Development of Novel Clinical Tests to Diagnose and Monitor Asthma in Preschool Children

Bronchodilator (Salbutamol - dose dependent on participant prescription) to wheezing subjects. 15 minutes after bronchodilator, spirometry and FOT repeated.

Child will be tested for allergies to 17 different allergens, and positive (histamine) and negative (glycerin) controls, for a total of 19 allergens.

Facemask in children 3-5 yrs, Wash-in phase: medical air inhaled during tidal breathing until steady state. Bias flow switched to 100% oxygen. Wash-out phase: patient breathes in 100% oxygen until nitrogen levels reach \~2%. Each test in duplicate and average is calculated.

Sterile mouthpiece attached to FOT device. Patient is tested seated with noseclips and mouthpiece. FOT device produces oscillations at different frequencies (from that flow into lungs. Device measures resistance and reactance in lungs.

Forced exhale manoeuvre completed by participant into flow meter, measuring forced exhale volumes and speed.

Given during bronchodilator response.

Nasal brush of 1 inferior turbinate to collect epithelial cells. Collected on either nare, choice dependent on how clear the nare is (i.e. no mucous, no nasal mucosal edema, no major structural impediments).

8mLs of venous blood collected using a butterfly needle of appropriate gauge. Blood sample used to collect CBC values, total IgE, serum, DNA, plasma, and whole blood.

Collect basophils from whole blood sample, and expose cells to food allergens in flow cytometry machine to measure allergic response, if any.

Gentle swabbing of both nasal openings to collect mucous sample for analysis of microbial contents (i.e. bacteria, virus, fungi).