Association between Doppler ultrasound of the superior mesenteric artery and different types of shock in critically ill patients

Abstract Background Reduced effective circulating blood volume and impaired peripheral perfusion are significant factors in the development of shock. we investigated the differences in superior mesenteric artery (SMA) Doppler ultrasound parameters among different types of shock. Additionally, we evaluated Whether SMA Doppler ultrasound is associated with lactate levels and the ability to predict hyperlactatemia in patients with shock. Methods This prospective observational study was conducted at a tertiary general and teaching hospital in China. From January 2023 to August 2023, 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 We evaluated a total of 85 patients, including 63 patients with different types of shock and 22 in the control group. In the cardiogenic 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. Lactate levels was correlation with SMA RI and PI. Based on the lactate level at the time of measurement, we divided the patients into the normal and hyperlactatemia groups. The hyperlactatemia group had lower SMA RI (0.72 ± 0.09 vs. 0.81 ± 0.05, P < 0.0001) and SMA PI (1.60 ± 0.48 vs. 2.22 ± 0.49, P < 0.0001) compared to the lactate normal group. The cut-off value of SMA RI for predicting hyperlactatemia was ≤ 0.78 with a sensitivity of 0.81 and a specificity of 0.79. Similarly, the cut-off value of SMA PI for predicting hyperlactatemia was ≤ 1.79 with a sensitivity of 0.87 and a specificity of 0.74. Conclusions SMA Doppler ultrasound plays a significant role in identifying various types of shock, particularly cardiogenic shock. The measurements of SMA RI and PI are correlated with lactate levels, have a positive predictive value for hyperlactatemia and provide guidance for fluid resuscitation in patients with shock in the future.