Correlation between measured (NOMEAS) and calculated (NOCALC) inspiratory tracheal concentrations of NO during sequential administration. The x-axis represents inspiratory tracheal NO concentration measured by fast-response chemiluminescence apparatus. The y-axis represents the difference between the measured and calculated inspiratory tracheal NO concentrations. The dark horizontal line represent the mean error and the two dotted lines on either side represent the precision (± 2 SD). Calculated inspiratory tracheal concentrations are very close to the measured inspiratory tracheal concentrations as indicated by a low bias and high precision. Published with permission .