Changes in superior mesenteric artery blood flow velocity monitored by ultrasound can predict enteral nutrition intolerance in mechanically ventilated critical ill patients
Objective:To explore the predictive value of blood flow velocity changes in superior mesenteric artery (SMA) monitored by ultrasound on feeding intolerance (FI) of enteral nutrition (EN) in mechanically ventilated ICU patients. Methods:One-hundred and eight mechanically ventilated patients in Intensive Care Department of the Second People's Hospital of Nantong from February 2022 to February 2023 were enrolled. SMA blood flow parameters and enteral nutrition tolerance were monitored on the 1st,3rd,and 7th day (D1,D3,D7) after initiation of EN. Differences in SMA blood flow parameters between tolerant and intolerant group,as well as intolerant subgroups (mild,moderate,and severe) were analyzed. The predictive value of SMA blood flow parameters for FI and the risk factors of FI were also evaluated,and the relationship between SMA blood flow parameters and intestinal barrier function were preliminarily explored . Result:The SMA blood flow velocity parameters,peak systolic velocity (PSV) and end diastolic velocity (EDV),were higher at D1,D3,and D7 in the tolerant groups compared to the intolerant group (all P<0.05). Subgroup analysis showed that as the degree of intolerance increased,PSV gradually decreased. EDV at D1,D3,and D7 also gradually decreased with the increased severity of FI (all P<0.05);The AUC of PSV and EDV predicting FI in D1,D3,and D7 patients were 0.752 (95% CI:0.660~0.830) and 0.773 (95% CI:0.682~0.848),0.774 (95% CI:0.683~0.849) and 0.796 (95% CI:0.708~0.868),0.743 (95% CI:0.650~0.822) and 0.713 (95% CI:0.618~0.796). respectively. PSV,norepinephrine use,and blood phosphorus levels were independent prognostic factors for FI at D3. Patients with FI showed a negative correlation between PSV,EDV,and diamine oxidase (PSV:r=-0.857,P<0.001;EDV:r=-0.795,P<0.001). Conclusion:Changes in blood flow velocity in the superior mesenteric artery by ultrasound monitoring can effectively predict enteral nutrition intolerance in mechanically ventilated patients,it might have potential clinical application values in ICU patients.