The structure of the gastrointestinal tract is complex, with many physiological functions. When the balance of Systemic Inflammatory Response Syndrome and Compensatory Anti-inflammatory Response Syndrome (SIRS/CARS) was broken, gastrointestinal function is often impaired. In a study of 242 patients who underwent mechanical ventilation for longer than 48 hours, the incidence of gastrointestinal bleeding was 46.7%, most of which occurred within 48 hours postoperatively. Proper mechanical ventilation Settings can protect gastrointestinal function[9, 10].The use of high pressure ventilator, renal failure, decreased platelet count were important risk factors for gastrointestinal bleeding, while enteral nutrition was an independent protective factor.
Successful enteral nutrition therapy for severely ill patients can promote the repair of gastrointestinal mucosa, promote the recovery of gastrointestinal function, and reduce the rate of endogenous infections. Nevertheless, some patients are feeding-intolerant, characterized by gastric retention, vomiting, diarrhea, and abdominal distention.Therefore, it is extremely important to effectively and comprehensively assess the status of gastrointestinal function, and then to guide the timing of initiation of enteral nutrition treatment [15, 16] .
In previous studies of our team , it was found that intra-abdominal pressure could not reflect the absorption function state of intestinal function;Successful enteral nutrition treatment can promote the improvement of gastrointestinal function indicators such as gastric antrum cross-sectional area, colon diameter and peristalsis frequency [18, 19]. In IAP similar states, although circulation is stable, some patients do not have synchronous recovery of intestinal function.This phenomenon is not reflected by abdominal examination and IAP. It indicates that gastrointestinal ultrasound can better evaluate the damage state of gastrointestinal function, and enteral nutrition therapy can be carried out earlier.
Continuous feeding of short peptide nutritional preparations can achieve the target calorie.There were fewer feeding complications. When enteral nutrition is absorbed, it promotes intestinal mucosal repair and contributes to the recovery of humoral and cellular immune function in the early post-traumatic period .
Comparison of the gastrointestinal assessment results of the successful and failed groups at the initiation of enteral nutrition showed no significant difference in IAP at the initiation of EN.There were statistical differences in the start time of EN, CSA, D and F, suggesting that the successful group may have a better basis of gastrointestinal function and less gastrointestinal function injury, which means we can start enteral nutrition therapy earlier.
We found that IAP ≤ 16mmHg, AUC 0.502, IAP does not reflect gastrointestinal function;CSA ≤ 9cm2, AUC 0.896;D ≤ 2.9cm, AUC 0.92;F > 3 BPM, AUC0.845;The results indicated that the three indexes could reflect the recovery of gastrointestinal function.When CSA, D and F were combined, the positive predictive value and AUC of CSA, D and F were higher than those of single index, the difference was statistically significant (P < 0.001), except for D + F combination (P > 0.05).When the patients met the combination of the above three indicators, namely CSA ≤ 9cm2, D ≤ 2.9cm, F > 3bpm, and AUC 0.95, enteral nutrition therapy was initiated, with a successful measurement value of 93.7%, suggesting a more complete assessment of gastrointestinal function.
The disadvantage of this study is that the single-center study has a small number of cases, which needs to be confirmed by more studies.