Noradrenaline modifies arterial reflection phenomena and left ventricular efficiency in septic shock patients: A prospective observational study

Purpose To determine whether noradrenaline alters the arterial pressure reflection phenomena in septic shock patients and the effects on left ventricular (LV) efficiency. Material and methods Thirty-seven septic shock patients with a planned change in noradrenaline dose. Timing and magnitude (Reflection Magnitude and Augmentation Index) of arterial reflections were evaluated. Total, steady, and oscillatory LV power (also expressed as fraction of the total power), subendocardial viability ratio (SEVR), energy efficiency and transmission ratios were used as a marker of LV efficiency. Results An incremental change in noradrenaline increased Reflection Magnitude [0.28(0.09) to 0.31(0.1], Augmentation Index [−6.4(23.6) to 4.8(20.7)%], and LV total power [0.79(IQR:0.47–1) to 0.98(IQR:0.57–1.27)W], all p < 0.001; whereas decreased arrival time of reflected waves [from 95(87 to 121) to 83(79 to 101)ms; p < 0.001]. Variables of LV performance showed a decreased efficiency: oscillatory fraction and energy efficiency ratio increased [20.9(5.7) to 22.8(4.9)%, and 8.2(1.7) to 10.1(2) mW.min.litre−1; p < 0.001, respectively]; and energy transmission ratio and SEVR decreased [73.8(9.9) to 72(9.8)% and 146(IQR:113–188) to 143(IQR:109–172)%, p = 0.003 and p = 0.041, respectively]. Conclusions Noradrenaline increased reflection phenomena, increasing LV workload and worsening LV performance in septic shock patients. These conditions could explain the detrimental effects during long-term use of noradrenaline.