Relationship between the individual mean bronchodilatory response of airway resistance (Rint, percentage decrease from baseline) when (a) 200 μg (n =8) and (b) 600 μg (n =10) salbutamol were given with volume control (RintVC) and pressure control (RintPC). The mean bronchodilatory response in each patient was obtained by averaging the Rint response at 15, 30 and 60min after salbutamol. For clarity of presentation, the mean bronchodilatory response was used instead of data at various time intervals after drug administration. The significant linear relationships did not change by pooling all data. Note that significant bronchodilatation was observed both with 200 and 600 μg salbutamol. Note also that the magnitude of bronchodilatation was not affected by the mode of ventilatory support. The continuous line is the regression line, and the dashed line represents the line of identity. From Mouloudi et al [41**].