Investigating the Energy Expenditure of Acute Spinal Cord Injured Patients

Overview

It is recognised that weight gain is a common problem in patients with a spinal cord injury and can lead to an increased incidence of metabolic syndrome. Weight gain is thought to be attributed to excess calorie intake, reduction in energy requirements and / or a reduction in exercise. However, further understanding of this energy imbalance needs to be addressed. This feasibility study will initially determine if it is feasible to measure the 'actual' energy requirements of 15 paraplegic and 15 tetraplegic (ventilated and non-ventilated) in-patients during bed rest and rehabilitation following acute SCI. This preliminary data will be compared to 'predicted' energy expenditure levels. The calorie intake and body composition for each patient will be measured as well as factors indicative of metabolic syndrome. The study will initially provide statistical information in order to estimate the sample size required for a future definitive study.

Introduction: There are an estimated 40,000 people living with a Spinal Cord Injury (SCI) in the UK alone (http://www.apparelyzed.com/statistics.html). Although there have been improvements in medical care, mortality rates are still elevated compared to the able-bodied population. The most common underlying and contributing causes of death in SCI patients are diseases of the circulatory and respiratory system. It is recognised that weight gain is a common problem in patients with a SCI, typically occurring within the first year of rehabilitation and continuing life long. SCI patients have been shown to have an increased fat mass, waist circumference and altered lipid profile. Obesity in SCI patients can lead to an increased incidence of metabolic syndrome. Patient weight gain is thought to be attributed to the reduction in energy expenditure compared to pre-injury levels, the loss of voluntary muscle use below the spinal cord lesion and reduction in lean tissue mass. It has been shown that the basal metabolic rate (BMR) of SCI patients is lower than predicted, with the greatest difference being for high tetraplegics. Findings suggest there is an overestimation of energy requirements in a small population of medically stable SCI patients. In addition, SCI calorie and protein intake is high in this patient population, suggesting that patients are also exceeding their nutritional recommendations. Excess calorie intake, reduction in energy requirement and / or a reduction in exercise will predispose the SCI patient to weight gain and obesity. Further understanding of this energy imbalance needs to be addressed. This single centre feasibility study will initially determine if it is feasible to measure the 'actual' energy requirements of paraplegic and tetraplegic (ventilated and non-ventilated) in-patients during bed rest and rehabilitation following acute SCI. This preliminary data will be compared to 'predicted' energy expenditure levels. The calorie intake and body composition for each patient will be measured as well as factors indicative of metabolic syndrome. The study will initially provide statistical information in order to estimate the sample size required for a future definitive study on energy expenditure and development of metabolic syndrome in SCI patients. In addition, the feasibility study will address patient recruitment rates and reasons for withdrawal from the study and highlight any practicality issues with study conduct. Recruitment: 15 acute paraplegic and 15 acute tetraplegic (ventilated and non-ventilated) inpatients will recruited. Methodology: The following procedures will be performed at bed rest, early mobilisation and hospital discharge: Measurement of Actual Energy Expenditure Actual resting energy expenditure (REE) is determined by measuring the oxygen consumption and carbon dioxide production of a patient at rest using the GE Healthcare metabolic oxygenator. During the test, the individual is interfaced with a metabolic measurement system by means of a facemask. For ventilated patients, the monitor will be used with a cuffed tracheostomy tube. Software will be used to calculate the respiratory quotient (RQ). Calculating Predicted Energy Requirements Henry equations are used to predict the basal metabolic rate. Adjustments are made based on metabolic stress associated with illness and for obese individuals. Determining Dietary Intake The patient's dietary intake will be reported using the standard hospital food charts. These will be completed for all food and fluids taken providing an indication of portion sizes. The charts will be kept for 3 consecutive days at each time point and is based on a pragmatic approach to improve accuracy of completion over a short period of time whilst still providing daily variations in intake. Data will be collected so that it covers at least one day of a weekend. Anthropometric Measurements Anthropometric measurements will be taken to determine patient body fat and muscle. The following parameters will be measured: 1. Mid Upper Arm Circumference (MUAC) 2. Tricep Skinfold Thickness (TSF) Mid Arm Muscle Circumference (MAMC) will be calculated using the equation: MAMC = MUAC - 3.14 x TSF Metabolic Syndrome Measurements The following will be measured: 1. Weight 2. Height 3. BMI Calculation 4. Blood Pressure 5. Waist Circumference 6. Fasting glucose, HDL, triglycerides