Aalternative ccriteria oof nnormality.
Abnormal rv tlc ratio.
A positive correlation was observed between rv to age r 0 4 and height r 0 3.
8 racial adjustment of predicted value most studies for normal values in us looked at caucasian populations of normals not apppp p g propriate for other ethnic groups if used in african american population more likely to seem abnormal 12 higher controversial.
A significant bronchodilator response was observed in 32 of the patients.
Furthermore a recent study has reported abnormal rv tlc ratios even in presence of normal fev1 fvc ratios in patient with mild to moderate persistent asthma.
Fifty two and fifty seven percent of the patients had abnormal residual volume and abnormal rv tlc ratio respectively.
Abnormal rv tlc ratio was a superior criterion for diagnosing obstruction in asthma.
Then taking the ratio of observed and predicted intro duces an age related bias an undesirable feature.
Abnormal rv tlc ratio was a superior criterion for diagnosing obstruction in asthma.
Agreement and bias normal abnormal kappa bias p value plethysmography actual 40 40 79 5 yes 0 0006.
While fev1 improvement with bronchodilator may be a function of large airway reversibility lack of significant rv reversibility may indicate small airway closure that is non reversible.