Reduced sensitivity due to the increased distance between receive coil-array and the heart, breathing problems, affecting breath-hold, resulting in variable breath-hold times, and/or ECG detachment due to sweating may place additional constraints on the application of H-MRS in this patient group.
The covariates were included in multivariable models for adjustment if they modified effect estimates for associations between the exposure variables (CO breath and tube) and the outcome variables (respiratory symptoms and lung function) by at least 5%.
The cardinal features of asthma include wheeze, shortness of breath, variable and reversible airway obstruction, airway hyperresponsiveness, mucus production and airway inflammation.
No transformation was necessary for PCE in exhaled breath variables.
Gas exchange and ventilatory variables were analysed breath by breath averaged over 10-second intervals using a computer-based system; study details are given elsewhere [ 20].
Prolonged expiration was a significant predictor for having one or more exacerbations, whereas all the chest findings variables except diminished breath sounds were significant predictors for having two or more exacerbations.
For the second winter data from observer two, the counted respiratory rates were converted into a binary variable using 40 breaths per minute as the upper limit of normal for children aged up to one year and 30 breaths per minute for children aged up to five years of age [ 14].
In the surgically treated cases the variables abdominal sounds, breath rate, CRT, PCV, haemoglobin and lactate were excluded due to high correlation to heart rate (heart rate/abdominal sounds þ = 0,52, heart rate/respiratory rate þ = 0.53, heart rate/CRT þ = 0.61, heart rate/PCV þ = 0.67, heart rate/HGB þ = 0.63 and heart rate/lactate þ = 0,59).
We did, however, observe highly variable and surprisingly low breath pH values in a majority of these student athletes.
After adjustment for demographic variables and shortness of breath, NT-proBNP ≥150 pg/mL was found to increase the risk of death by 58% (HR=1.58 (1.09–2.30)).
For exposure variables, the end-exhaled breath concentration was most sensitive to the estimated air concentration of naphthalene during work (NSC = 1.0).
