Correlation Between Intestinal Blood Flow and Intestinal Dysfunction in Critically Ill Patients
Currently in the field of critical care, altered intestinal blood flow in critically ill patients has been a hot research topic in recent years. However, because the gastrointestinal tract is in the abdominal cavity and the clinic lacks perfusion direct monitoring means, at present, gastrointestinal function indicators are mostly used to guide the clinic, and the treatment is often blind and lagging. Gastrointestinal perfusion Research on gastrointestinal perfusion is mostly confined to abdominal perfusion pressure (mean arterial pressure - intra-abdominal pressure). However, according to the "Darcy law" in blood flow mechanics, Q=MAP/SVR, which means pressure≠flow. The investigators may not be able to ensure adequate blood flow to the digestive organs by relying on intra-abdominal perfusion pressure alone. Direct organ flow monitoring is a more accurate means of organization. The superior mesenteric artery (SMA) supplies all of the intestinal tract (small bowel, part of the colon) and is a long vessel that can to reflect the perfusion status of the distal overall bowel. Color Doppler ultrasonography is used to evaluate intestinal vessels such as the SMA in healthy and outpatient patients. The use of color Doppler ultrasonography to assess blood flow in intestinal vessels such as the SMA in healthy and outpatient patients has been in use since the 1980s. The investigators' team showed that the resistance index of the SMA in postoperative cardiac surgery patients correlated with lactate values and lactate clearance [Front Med (Lausanne), 2021.8:p.762376.], suggesting that gastrointestinal perfusion as reflected by SMA blood flow is important for systemic resuscitation, and that Doppler indices of SMA have the potential value of reflecting intestinal hypoperfusion. The Doppler index of SMA has the potential value of reflecting intestinal hypoperfusion. Intestinal venous blood enters the portal vein and then the liver before returning to the right heart via the inferior vena cava. Right heart dysfuction, right atrial hypertension, and abdominal hypertension can cause obstruction of portal venous return, which can lead to edema and dysfunction of the bowel. This can lead to edema of the intestinal tract and dysfunction. Therefore, monitoring the venous return status of portal vein, hepatic vein and inferior vena cava is also important for the perfusion of the intestine. Therefore, monitoring the status of venous return in the portal vein, hepatic vein, inferior vena cava, etc. is also important for intestinal perfusion. Doppler ultrasound technology has been widely used in the field of cardiac critical care and craniocerebral critical care, but it is still in the exploratory stage in the field of critical care digestion, and this study is an innovative and exploratory one.