Effect of different shock conditions on mesenteric hemodynamics

Background: Reduced effective circulating blood volume and impaired peripheral tissue perfusion play an important role in the pathophysiology of shock. However, there have been no studies examining the relationship between Doppler ultrasound of the superior mesenteric artery (SMA) under different shock conditions.Methods: We evaluated a total of 85 patients, including 63 patients with different types of shock and 22 in the control group. we included patients who were diagnosed with shock upon admission or developed shock during their hospital stay. At the same time, patients with stable hemodynamics, no use of vasoactive drugs and normal lactate levels were used as a control group. We collected SMA Doppler ultrasound parameters, including Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Resistance Index (RI), pulsatility index (PI), Time-Averaged Mean Velocity (TAMV), and Blood Flow (BF).Results: In the cardiac shock group, SMA PSV, TAMV, and BF were lower compared to the other groups. There was no significant difference in SMA RI and PI between the different types of shock groups, but both were significantly lower than the control group. Cardiac index (CI) is correlated with SMA PSV (r = 0.487, P = 0.000) and TAMV (r = 0.538, P = 0.000), whereas SVRI is not correlated with SMA RI and PI. Lactate levels was correlation with SMA RI (r = -0.307, P = 0.000) and PI (r = -0.287, P = 0.000). The area under the ROC curve of SMA RI and PI to predict hyperlactatemia was 0.85[0.78-0.91] and 0.83[0.76–0.90].Conclusions: The velocity parameters of SMA Doppler ultrasound such as TAMV and PSV can reflect cardiac function. The measurements of SMA RI and PI are correlated with lactate levels, having a positive predictive value for hyperlactatemia and provide guidance for fluid resuscitation in patients with shock in the future.