Ultrasound Meal Accommodation Test to Predict Enteral Feeding Tolerance of Enteral Feeding in Critically Ill Patients

Within the context of intensive care units (ICU), enteral nutrition is an essential tool in the management of critical patients, because it preserves the structure and function of the gastrointestinal mucosa, decreases the catabolic response to injury when it is administered early, and could also reduce the incidence of bacterial translocation. These factors could play an important role in reducing infectious complications, compared with parenteral nutrition. Current clinical practice guidelines, have agreed on the need to implement early enteral nutrition in the critically ill patient. Moreover, today it is considered one of the quality standards in the intensive care units. However, it is often not feasible to initiate early enteral nutrition , due to the high incidence of gastrointestinal complications that act as a limiting factor. Within the gastrointestinal complications seen in the critically ill patient, gastroparesis is usually the most frequent caused in general by the delay of gastric emptying in the absence of mechanical obstruction, and is manifested by a high volume of gastric residue. It is a frequent problem and difficult to manage in ICUs, with a reported incidence of up to 50-60% in critical patients in mechanical ventilation (MV). Gastroparesis causes significant difficulties in implementing enteral nutrition, and constitutes one of the main medical or non-avoidable causes of its suspension; it can also cause hydroelectrolytic and acid-base disorders if the volume of gastric residue is of great magnitude. In addition, gastroparesis may favor gastroesophageal reflux and bacterial overgrowth, with increased risk of pulmonary aspiration, pneumonia and sepsis. Several factors have been implicated in the deterioration of gastrointestinal motility in critical patients. The most important are mechanical ventilation, the use of opioids, catecholamines (mainly dopamine), the presence of brain injury, sepsis, hyperglycemia, supine position, among others. However, there are aspects not yet defined with respect to their diagnostic criteria and their management.

Gastric ultrasound is a validated tool to non-invasively evaluate gastric volume and content and predict the risk of pulmonary aspiration. It has a high sensitivity and specificity that makes it a gold standard. Its implementation in the preoperative evaluation of emergency surgery has proven to be a cost-effective test, that allows reducing the morbidity and mortality of patients, establishing preventive measures and intubation techniques that limit or eliminate the risk of pulmonary aspiration, reducing the days of stay Hospital and mortality.

Based on the knowledge generated by gastric ultrasonography, the concept of "risk stomach" was coined. Bouvet defines "stomach of risk" when the gastric volume exceeds 0.8 mL / kg of weight, measured by transverse ultrasound at the level of the gastric antrum.

This model can predict volumes from 0 to 500 mL and is applicable to adult patients with a body mass index of less than 40 kg / m2. The sensitivity and specificity of this model is 100%, which makes it the "gold standard" for non-invasive assessment of the stomach risk of lung gastric aspiration. The margin of error of the measurement is ± 6 mL.

In patients with dyspepsia, the Gastric Accommodation Test guided by ultrasound has given good results as a diagnostic method for gastrointestinal disorders.