Trophic Nutrition in Patients Submitted to High Flow Oxygen Therapy and / or Non Invasive Mechanical Ventilation

Overview

The decision about the initiation of enteral nutrition therapy in critically ill patients with oxygen therapy needs with HFC and / or NIMV is a matter of debate at present. Despite the benefits associated with this practice in critically ill patients, the scarcity of clinical studies in patients with sufficient methodological quality, as well as the absence of specific recommendations on enteral nutrition therapy in this type of patient, generates controversy in the professionals involved in critical patient care.

Ventilation and oxygenation of patients, even more in Intensive Care Units (ICUs), are in continuous development. The characteristics of patients, pathologies and diagnostic methods are constantly evolving. Among the main methods of ventilation and oxygenation that the investigators have are Non-invasive mechanical ventilation (NIMV) with face mask and high-flow cannula (HFC). NIMV has represented an alternative in patients with failure to extubate, as an option before proposing a new reintubation. The ventilation with high flow has supposed an advance in the oxygenation of patients in situation of respiratory insufficiency, avoiding the intubation, and also has been a resource that allows the disconnection of the mechanical ventilator, reducing with it the time of mechanical support of the ventilation, There is a great amount of bibliography and a broad consensus on this aspect. Among the side effects widely studied, include bronchoaspiration, gastric insufflation, aerophagia and sialorrhea, which are usually well controlled with medical treatment. The high flow ventilation consists of increasing the gas mixture, by releasing high oxygen and air flows, approximately up to 60 l/min, in modifiable proportions, so that positive pressures are achieved in the airway, facilitating the entry of this gas in the lung under spontaneous ventilation, with better oxygenation figures than conventional oxygen therapy methods. This positive pressure increase could be a facilitator of digestive intolerance either by air swallowing and gastric distension, or by promoting incontinence of the esophageal sphincters and thereby facilitating regurgitation and bronchoaspiration of the gastric contents. NIMV consists of a ventilatory support applied without placement of endotracheal or pharyngeal devices, achieving increased alveolar ventilation by applying positive pressures throughout the airway through an interface (acting on the pressure gradient of the airway, to maintain an adequate gas exchange, impossible to achieve with spontaneous physiological ventilation). This positive pressure increase, as in ventilation with HFC, could also be an element that promotes digestive intolerance. Patients in respiratory failure have a high level of metabolic stress that leads to a hypercatabolic situation and can not feed themselves for days, thus increasing the risk of malnutrition or worsening pre-existing malnutrition. This situation, as well as the development of negative energy balances in the critically ill patient, is associated with several complications, thus increasing morbidity and mortality, hospital stay and costs. The nutritional risk that this situation determines is high, which is why artificial nutrition therapy is justified. This nutritional therapy in spontaneous ventilation is usually attempted to be supplemented by oral feeding, but in patients who require artificial supports to aid in ventilation and oxygenation, it is not so easy to receive and tolerate adequate levels of caloric and protein intake. Enteral nutrition through the gastric route is frequently the method chosen for artificial nutritional therapy in patients with nutritional risk. This is due the advantages that the maintenance of the digestive tract in functional state will determine in the health of the patient, since the lack of nutrients in the lumen of the intestine can trigger a loss of the anatomical and functional integrity of the intestinal epithelium, with a rupture of the intestinal barrier that can favor, through a pro-inflammatory immune response, the evolution towards the multiple organ dysfunction syndrome.