[Maximal static respiratory pressures. The importance of the study of normal reference values]

In order to determine the validity for our population of the theoretical reference values available in the literature today, we studied respiratory muscle force by calculating maximum expiratory pressure PEmax and maximum inspiratory pressure (PImax) in 100 healthy subjects in Asturias (50 women) between 17 and 80 years-old (mean 40.4 +/- 19.3 years). We used the same methods and apparatus as Black and Hyatt and compared the results with theoretical values given by them as references corresponding to our subjects, according to age and sex. Values were significantly lower (p < 0.001) in our population for both parameters and for both men and women. In men PEmax was 69.7% and PImax was 88.5% of the theoretical values, in women PEmax was 60.9% and PImax was 82.9%. These figures indicate that the theoretical values given by Black and Hyatt are not valid for the population we studied and that normal reference values appropriate for each population, laboratory and apparatus must be obtained if valid conclusions are to be reached.