Variation in metabolic demand following severe pediatric traumatic brain injury: A case review.

A traumatic brain injury (TBI) is one of the most common pediatric traumas among children in the United States. Appropriate nutrition support, including the initiation of early enteral nutrition, within the first 48 h after injury is crucial for children with a TBI. It is important that clinicians avoid both underfeeding and overfeeding, as both can lead to poor outcomes. However, the variable metabolic response to a TBI can make determining appropriate nutrition support difficult. Because of the dynamic metabolic demand, indirect calorimetry (IC) is recommended, instead of predictive equations, to measure energy requirements. Although IC is suggested and ideal, few hospitals have the technology available. This case review discusses the variable metabolic response, identified using IC, in a child with a severe TBI. The case report highlights the ability of the team to meet measured energy requirements early, even in the setting of fluid overload. It also highlights the presumed positive impact of early and appropriate nutrition provision on the patient's clinical and functional recovery. Further research is needed to investigate the metabolic response to TBIs in children and the impact optimal feedings based on the measured resting energy expenditure have on clinical, functional, and rehabilitation outcomes.

Mechanistic Understanding of High Flow Nasal Cannula Therapy and Pressure Support with an In Vitro Infant Model.

Despite the increased use of high flow nasal cannula therapy, little has been done to predict airway pressures for a full breath cycle. A 3-month-old infant in vitro model was developed, which included the entire upper airway and the first three bifurcations of the lungs. A breathing simulator was used to create a realistic breath pattern, and high flow was provided using a Vapotherm unit. Four cannulas of varying sizes were used to assess the effects of the inner diameter and nasal occlusion of the cannulas on airway pressures. At 8 L min-1, end expiratory pressures of 0.821-1.306 cm H2O and 0.828-1.133 cm H2O were produced in the nasopharynx and trachea, respectively. Correlations were developed to predict full breath cycle airway pressures, based on the gas flow rate delivered, cannula dimensions, as well as the breathing flow rate, for the nasopharynx and trachea. Pearson correlation coefficients for the nasopharynx and trachea correlations were 0.991 and 0.992, respectively. The developed correlations could be used to determine the flow rate necessary for a cannula to produce pressures similar to CPAP settings. The proposed correlations accurately predict the regional airway pressure up to and including 7 cm H2O of support for the entire breath cycle.