Measuring energy requirements during pulmonary exacerbations of cystic fibrosis using indirect calorimetry

OBJECTIVE

The energy demands of individuals with cystic fibrosis (CF) vary depending on pancreatic function, body composition, lung function, and clinical status. In clinical practice, predictive equations are used to determine energy requirements yet do not reliably account for these factors. Research regarding energy requirements during CF pulmonary exacerbation (CFPEx) and clinical stability is conflicting. The aim of this study was to investigate potential within-individual changes in measured resting energy expenditure (mREE) using indirect calorimetry (IC) at the commencement and completion of intravenous antibiotic treatment (IVABx) for CFPEx and during clinical stability. Secondary aims were to investigate potential differences between predicted resting energy expenditure (pREE) using Schofield equation and correlations between clinical factors with mREE.

METHODS

Body composition using bioimpedance analysis and mREE were conducted at three time points: commencement of IVABx; completion of IVABx; and clinically stable period thereafter.

RESULTS

Twenty-eight adults with CF completed at least one valid IC measurement. No significant within-person changes in mREE and body composition parameters were observed across time points. The mREE was positively correlated with fat-free mass (kg; r = 0.6; P = 0.008). The mREE was significantly higher than pREE at all time points with the mREE/pREE ratio elevated at time point 1:118% ± 19.5%; time point 2: 112% ± 13.2%; and time point 3: 122 ± 14.3%.

CONCLUSION

The mREE remained stable during CFPEx and clinical stability. The pREE underestimated mREE and application of injury factor adjustment of 110% to 130% could potentially account for this discrepancy. The potential role of IC and body composition in individualizing CF nutritional assessment and prescription requires further exploration.

Calibration and validation of accelerometry using cut-points to assess physical activity in paediatric clinical groups: A systematic review

Regular physical activity is associated with physiological and psychosocial benefits in both healthy and clinical populations. However, little is known about tailoring the analysis of physical activity using accelerometers to the specific characteristics of chronic conditions. Whilst accelerometry is broadly used to assess physical activity, recommendations on calibration in paediatric clinical groups are warranted. The aim of this systematic review was to provide a critical overview of protocols used to calibrate accelerometry in children and adolescents with clinical conditions, as well as to develop recommendations for calibration and validation of accelerometry in such populations. The search was performed between March to July 2017 using text words and subject headings in six databases. Studies had to develop moderate-to-vigorous intensity physical activity (MVPA) cut-points for paediatric clinical populations to be included. Risk of bias was assessed using a specific checklist. A total of 540,630 titles were identified, with 323 full-text articles assessed. Five studies involving 347 participants aged 9 to 15 years were included. Twenty-four MVPA cut-points were reported across seven clinical conditions, 16 of which were developed for different models of ActiGraph, seven for Actical and one for Tritrac-R3D. Statistical approaches included mixed regression, machine learning and receiver operating characteristic analyses. Disease-specific MVPA cut-points ranged from 152 to 735 counts·15 s-1, with lower cut-points found for inherited muscle disease and higher cut-points associated with intellectual disabilities. The lower MVPA cut-points for diseases characterised by both ambulatory and metabolic impairments likely reflect the higher energetic demands associated with those conditions.

Characteristics of Resting Metabolic Rate in Critically Ill, Mechanically Ventilated Adults With Cystic Fibrosis

BACKGROUND

Critically ill patients with cystic fibrosis may be especially sensitive to the negative consequences of overfeeding and underfeeding, yet there is almost no information available about the energy needs of these patients. The purpose of this study was to characterize the metabolic rate of critically ill adult patients with cystic fibrosis requiring mechanical ventilation.

METHODS

This was an observational study in which the resting metabolic rate, oxygen consumption, and carbon dioxide production of adult patients with cystic fibrosis requiring critical care, sedation, and mechanical ventilation were measured with indirect calorimetry. This group was compared with a cohort of adult critical care patients without cystic fibrosis.

RESULTS

Twelve patients with cystic fibrosis were identified and measured. These were compared with a control group of 25 critically ill patients. Both groups were underweight (body mass index, 17.4 ± 4.0 kg/m² in cystic fibrosis and 18.4 ± 2.3 kg/m² in control). Adjusting for differences in age, sex, height, and weight, there was no difference in resting metabolic rate between the cystic fibrosis and control groups (1702 ± 193 vs 1642 ± 194 kcal/d, P = .388). Measured resting metabolic rate matched predicted values 58% of the time in cystic fibrosis and 60% of the time in control.

CONCLUSIONS

The resting metabolic rate of sedated adult patients with cystic fibrosis being assisted with mechanical ventilation is not different from that of adult critical care patients without cystic fibrosis. In both these underweight groups, accurate prediction of resting metabolic rate is difficult to obtain.

A systematic review of dynamometry and its role in hand trauma assessment

The dynamometer was developed by American neurologists and came into general use in the late 19th century. It is still used in various ways as a diagnostic and prognostic tool in clinical settings. In this systematic review we assessed in detail the different uses of dynamometry, its reliability, different dynamometers used and the influence of rater experience by bringing together and evaluating all published literature in this field. It was found that dynamometry is applied in a wide range of medical conditions. Furthermore, the great majority of studies reported acceptable to high reliability of dynamometry. Jamar mechanical dynamometer was used most often in the studies reviewed. There were mixed results concerning the effect of rater experience. The factors influencing the results of dynamometry were identified as age, gender, body weight, grip strength, BMI, non/dominant hand, assessing upper/lower limbs, rater and patient’s strength and the distance from the joint where the dynamometer is placed. This review provides an understanding of the relevance and significance of dynamometry which should serve as a starting point to guide its use in hand trauma assessment. On the basis of our findings, we suggest that hand dynamometry has a great potential, and could be used more often in clinical practice.

A prospective randomised study comparing oral 13C-bicarbonate tracer technique versus indirect calorimetry for measurement of energy expenditure in adults

BACKGROUND AND AIMS

Accurate assessment of energy expenditure (EE) is important in guiding nutritional therapy but current methods are unsatisfactory. This study compared the oral ¹³C-bicarbonate tracer (BT) technique using the IRIS® system (Wagner, Germany) against indirect calorimetry (IC, ventilated-hood) to measure CO₂ output (VCO₂) and thus estimate EE.

METHODS

Ten overnight-fasted healthy male volunteers were randomised to studies at rest or mild exercise in a crossover manner. During each study BT-IRIS® and IC were used simultaneously to measure VCO₂ and thus EE. Participants ingested a drink labelled with 50mg ¹³C-bicarbonate and breath samples were collected every 5 min for 180 min and analysed using IRIS®. Bland-Altman plots were used to assess agreement between the two techniques in measurements of VCO₂ (L/day) and estimates of EE (kJ/day).

RESULTS

Mean ± SE age and BMI of participants were 21.1 ± 1.1 yrs and 23.6 ± 0.6 kg/m². Both at rest and exercise, there was small bias but overall poor agreement between the two techniques as evident by the wide 95% limits of agreement in measurements of VCO₂ and EE: rest VCO₂ (bias 1.4, SD 93, 95% limits of agreement -180 to 183), rest EE (-8.3, 1830, -3595 to 3578), exercise VCO₂ (49.3, 66.1, -80.4 to 178.9) and exercise EE (1083, 1944, -2727 to 4893). Furthermore, there was also evidence of systematic error in these measurements.

CONCLUSION

Prior to clinical application, further optimisation of the BT-IRIS® system should be undertaken, given the poor agreement with IC in measuring VCO₂ and estimating EE.

[Validation of the Spanish version of the Revised Cystic Fibrosis Quality of Life Questionnaire in adolescents and adults (CFQR 14+ Spain)]

BACKGROUND

The aim of this study was to assess the validity and reliability of the Spanish version of the revised disease-specific health related quality of life questionnaire for adolescents and adults with cystic fibrosis (CFQR 14+ Spain).

METHODS

A total of 43 cystic fibrosis (CF) patients completed the CFQR 14+ Spain. Forced expiratory volume in 1 second, in percentage of predicted - FEV(1) (%)-, number of respiratory exacerbations, 6-minute walk test, Bhalla score (based on computerized tomography of the chest), fat-free mass index, body mass index (BMI), faecal fat and St George's Respiratory Questionnaire were included as measurements of health status.

RESULTS

Ten out of the twelve scales had alpha coefficients above 0.70. Test-retest correlations (Spearman) ranged from 0.49 to 0.95 and they were significant in all scales. Intraclass correlations ranged from 0.47 to 0.95 (ten out of the twelve scales were >0.70) forty out of the fifty ítems have correlations between items and scale above 0.70. All the CFQR+14 scales, except the digestive symptoms scale, discriminated significantly between patients with mild, moderate and severe disease (according to FEV(1) (%)). Other respiratory parameters also discriminated significantly between patients with mild-moderate and severe disease. Only some scales discriminated significantly between nourished and malnourished patients. All of the scales met standards for floor effects (<15% of the responders with the lowest score) but not for ceiling effects (only five out of the twelve).

CONCLUSION

The Spanish CFQR14+ (Spain) is a reliable and valid instrument for measuring the health-related quality of life in Spanish adolescents and adults with CF, though with the exception of a few of its subscales.