Fig. 4. Bias and precision of pulmonary capillary wedge pressure (PCWP) estimated from conventional Doppler, color M-mode Doppler, and Doppler tissue imaging in the test population. (Left ) Differences between PCWP measured from the pulmonary artery catheter and PCWP estimated from color M-mode Doppler (PCWP^Vp). According to the correlation shown in figure 2, PCWP^Vpwas calculated using the following formula: PCWP^Vp= 3.91 E/Vp + 4.92. The mean bias was 0.1 mmHg. The dotted lines represents 2 SDs (precision of the bias, according to the Bland-Altman method). (Right ) Differences between PCWP measured from the pulmonary artery catheter and PCWP estimated from Doppler tissue imaging (PCWP^Ea). According to the correlation shown in figure 2, PCWP^Eawas calculated using the following formula: PCWP^Ea= 0.97 E/Ea + 4.34. The mean bias was 0.4 mmHg. The dotted lines represents 2 SDs (precision of the bias, according to the Bland-Altman method).