Energy Balance out of Balance after Severe Traumatic Brain Injury
Abstract: The overall aim of the research presented here was to expand the knowledge on metabolic course and nutritional outcome in patients with severe traumatic brain injury and to analyze the use and accuracy of different methods of assessment.Study I, a systematic review of 30 articles demonstrated consistent data on increased metabolic rate, of catabolism and of upper gastrointestinal intolerance in the majority of the patients during early post injury period. Data also indicated a tendency of less morbidity and mortality in early fed patients.Study II, a retrospective survey, based on medical records of 64 patients from three regions in Sweden, showed that the majority of patients regained their independence in eating within six months post injury. However, energy intake was set at a low level and 68 % of the patients developed malnutrition with 10 to 29 % loss of initial body mass during the first and second month post injury.Study III, a questionnaire based study addressed to 74 care units caring for patients with severe traumatic brain injury showed that resources in terms of qualified staff members were reportedly good, but nutritional guidelines were adopted in less than half of the units, screening for malnutrition at admission was rarely performed and surveillance of energy intake declined when oral intake began. Moreover, assessment of energy requirements relied on calculations and the profession in charge to estimate energy requirement varied depending on nutritional route and unit speciality. At transferral between units nutritional information was lost.Study IV and V, a prospective descriptive study on metabolic course, energy balance and methods of assessment in six patients showed that patients were in negative energy balance from 3rd week post injury and lost 8-19 % of their initial body weight. Concurrent nutritional problems were difficulties in retaining enteral and/or parenteral nutrition delivery routes until oral feeding was considered satisfactory. The majority of methods for predicting energy expenditure agreed poorly with measured energy expenditure. The Penn-State equation from 1998 was the only valid predictive method during mechanical ventilation.This thesis concludes that patients with moderate or severe traumatic brain injury exhibit a wide range of increased metabolic rate, catabolism and upper gastrointestinal intolerance during the early post-injury period. Most patients regain independence in eating, but develop malnutrition. Suggested explanations, other than the systemic disturbances early post injury, could be the use of inaccurate predictions of energy expenditure, deficient nutritional routines and difficulties in securing alternative nutritional routes until oral feeding is satisfactory. The impact of timing, content and ways of administration of nutritional support on neurological outcome after a severe traumatic brain injury remains to be demonstrated.
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