Isoflurane's Effect on Intraoperative Systolic Left Ventricular Performance in Cardiac Valve Surgery Patients

Fig. 1. Patient recruitment and analysis diagram. Twenty-one patients were recruited and one was excluded due to the failure to align Doppler beam parallel to the axis of the lateral annular motion during the entire systolic period. LVEF = left ventricular ejection fraction, TTE = transthoracic echocardiography, TEE = transesophageal echocardiography, MAC = minimum alveolar concentration, BIS = Bispectral index, MV = mitral valve, TDI = tissue Doppler imaging, BP = blood pressure, HR = heart rate, bpm = beat per minute.

Fig. 2. Correlation and agreement of the first and second measurements of TDI parameters. Measure 1: first measurements of each variable. Measure 2: second measurements of each variable. The solid line shows the mean difference and the dash lines show the LOAs (mean difference ± 1.96 standard deviations). TDI = tissue Doppler imaging, S′ = peak velocity of the lateral mitral annulus during systole, e′ = peak velocity of tissue Doppler imaging mitral annulus during early relaxation, a′ = peak velocity of mitral annular TDI during late atrial contraction, LOA = limits of agreement, T1, T2, and T3 = after 10-minute-exposure to isoflurane 1.0, 1.5, and 2.0 MAC, respectively, MAC = minimum alveolar concentration.

Fig. 3. S′, e′, a′, and BIS during the increments of isoflurane dosage. The boxes show the 25th and 75th percentiles, and horizontal lines within the box show median values. The whiskers show the lowest and highest values in the 25th percentile minus 1.5 IQR and 75th percentile plus 1.5 IQR regions, respectively. The optimal hypnosis level for general anesthesia is a BIS value between 40 and 60. S′ = peak velocity of the lateral mitral annulus during systole, e′ = peak velocity of tissue Doppler imaging mitral annulus during early relaxation, a′ = peak velocity of tissue Doppler imaging mitral annulus during late atrial contraction, BIS = Bispectral index, IQR = interquartile range, T1, T2, and T3 = after 10-minute-exposure to isoflurane 1.0, 1.5, and 2.0 MAC, respectively, MAC = minimum alveolar concentration. aP < 0.05 vs. T1; bP < 0.05 vs. T2.