A feasibility study comparing two metabolic monitors in hospitalised patients following an ischaemic stroke

Abstract

Background: Data on the energy requirements of patients following acute ischaemic stroke are scarce. A recent draft report highlighted the lack of data on physical activity levels during and following acute illness (SACN, 2009). The aims of this study were to establish if two metabolic monitors (CCM Express™ and the Sensewear™ armband) were feasible for use in hospitalised stroke patients and to determine the relative contributions of resting energy expenditure (REE) and physical activity to total energy expenditure (TEE). Methods: Eleven medically stable patients (seven male; four female) were recruited within 7 days of ischaemic stroke. Exclusion criteria: unable to give informed consent, receiving renal replacement therapy, body mass index (BMI) ≥ 50 kg m−2, known nickel allergy or receiving end-of-life care. All subjects were fasted from midnight and REE was measured early in the morning using the CCM Express™ for a period of up to 1 h (including establishment of steady-state (i.e. <10% difference in minute to minute VO2 and VCO2 measurements over 5 min). Concurrently, TEE was measured using the Sensewear™ armband for a period of 24 h. Assessments of patient acceptability and tolerance of both metabolic monitors were conducted by direct observation, completion of a checklist and, where clinically appropriate, a brief patient questionnaire. REE was compared with predicted basal metabolic rate (BMR) (Henry, 2005) and physical activity was estimated using the Metabolic Equivalent Task (MET) method, where 1.0 MET is equivalent to the energy expended at rest. Results: Mean age was 69.8 years (range 42–84 years) and mean (SD) BMI was 25.4 (5.2) kg m−2. All subjects were able to tolerate measurement of REE using the CCM Express™, although the facemask caused some discomfort to one subject with facial abrasions. Mean (SD) REE was 1257 (357) kcal day−1 and, perhaps unexpectedly, was lower than predicted BMR [1503 (226) kcal day−1; t-test, P = 0.07]. It was, however, difficult to achieve steady-state in four patients; thus, these REE measurements were unreliable. All subjects were able to tolerate measurement of TEE using the Sensewear™ armband. Mean (SD) TEE was 1663 (303) kcal day−1. Physical activity on the ward was very low, with subjects expending very little more energy than would be expected at rest [METS = 1.01 (SD 0.15)]. Discussion: Both metabolic monitors were well tolerated by the subjects; however, the unreliable REE measurements in some patients made it impossible to determine the relative contribution of REE to TEE. The results obtained regarding TEE and the low activity level in this study were comparable to results reported in other metabolic studies of patients who have had a stroke (Weekes & Elia, 1992; Finestone et al., 2003; Leone & Pencharz, 2010). Conclusions: Both metabolic monitors were feasible for use in patients following ischaemic stroke; however, some measurements of REE using the CCM Express™ were unreliable because of difficulties in establishing steady-state and the reasons for this merit further investigation. In this group of patients, physical activity on the ward was very low following a stroke.