Chris Burtin

Early exercise in critically ill patients enhances short-term functional recovery*

Objectives:To investigate whether a daily exercise session, using a bedside cycle ergometer, is a safe and effective intervention in preventing or attenuating the decrease in functional exercise capacity, functional status, and quadriceps force that is associated with prolonged intensive care unit stay. A prolonged stay in the intensive care unit is associated with muscle dysfunction, which may contribute to an impaired functional status up to 1 yr after hospital discharge. No evidence is available concerning the effectiveness of an early exercise training intervention to prevent these detrimental complications. Design:Randomized controlled trial. Setting:Medical and surgical intensive care unit at University Hospital Gasthuisberg. Patients:Ninety critically ill patients were included as soon as their cardiorespiratory condition allowed bedside cycling exercise (starting from day 5), given they still had an expected prolonged intensive care unit stay of at least 7 more days. Interventions:Both groups received respiratory physiotherapy and a daily standardized passive or active motion session of upper and lower limbs. In addition, the treatment group performed a passive or active exercise training session for 20 mins/day, using a bedside ergometer. Measurements and Main Results:All outcome data are reflective for survivors. Quadriceps force and functional status were assessed at intensive care unit discharge and hospital discharge. Six-minute walking distance was measured at hospital discharge. No adverse events were identified during and immediately after the exercise training. At intensive care unit discharge, quadriceps force and functional status were not different between groups. At hospital discharge, 6-min walking distance, isometric quadriceps force, and the subjective feeling of functional well-being (as measured with “Physical Functioning” item of the Short Form 36 Health Survey questionnaire) were significantly higher in the treatment group (p < .05). Conclusions:Early exercise training in critically ill intensive care unit survivors enhanced recovery of functional exercise capacity, self-perceived functional status, and muscle force at hospital discharge.

Validity of Six Activity Monitors in Chronic Obstructive Pulmonary Disease: A Comparison with Indirect Calorimetry

Reduced physical activity is an important feature of Chronic Obstructive Pulmonary Disease (COPD). Various activity monitors are available but their validity is poorly established. The aim was to evaluate the validity of six monitors in patients with COPD. We hypothesized triaxial monitors to be more valid compared to uniaxial monitors. Thirty-nine patients (age 68±7years, FEV1 54±18%predicted) performed a one-hour standardized activity protocol. Patients wore 6 monitors (Kenz Lifecorder (Kenz), Actiwatch, RT3, Actigraph GT3X (Actigraph), Dynaport MiniMod (MiniMod), and SenseWear Armband (SenseWear)) as well as a portable metabolic system (Oxycon Mobile). Validity was evaluated by correlation analysis between indirect calorimetry (VO2) and the monitor outputs: Metabolic Equivalent of Task [METs] (SenseWear, MiniMod), activity counts (Actiwatch), vector magnitude units (Actigraph, RT3) and arbitrary units (Kenz) over the whole protocol and slow versus fast walking. Minute-by-minute correlations were highest for the MiniMod (r = 0.82), Actigraph (r = 0.79), SenseWear (r = 0.73) and RT3 (r = 0.73). Over the whole protocol, the mean correlations were best for the SenseWear (r = 0.76), Kenz (r = 0.52), Actigraph (r = 0.49) and MiniMod (r = 0.45). The MiniMod (r = 0.94) and Actigraph (r = 0.88) performed better in detecting different walking speeds. The Dynaport MiniMod, Actigraph GT3X and SenseWear Armband (all triaxial monitors) are the most valid monitors during standardized physical activities. The Dynaport MiniMod and Actigraph GT3X discriminate best between different walking speeds.

Validity of activity monitors in health and chronic disease: a systematic review

The assessment of physical activity in healthy populations and in those with chronic diseases is challenging. The aim of this systematic review was to identify whether available activity monitors (AM) have been appropriately validated for use in assessing physical activity in these groups. Following a systematic literature search we found 134 papers meeting the inclusion criteria; 40 conducted in a field setting (validation against doubly labelled water), 86 in a laboratory setting (validation against a metabolic cart, metabolic chamber) and 8 in a field and laboratory setting. Correlation coefficients between AM outcomes and energy expenditure (EE) by the criterion method (doubly labelled water and metabolic cart/chamber) and percentage mean differences between EE estimation from the monitor and EE measurement by the criterion method were extracted. Random-effects meta-analyses were performed to pool the results across studies where possible. Types of devices were compared using meta-regression analyses. Most validation studies had been performed in healthy adults (n = 118), with few carried out in patients with chronic diseases (n = 16). For total EE, correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices. For active EE, correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices. Uniaxial devices tended to underestimate TEE (−12.07 (95%CI; -18.28 to −5.85) %) compared to triaxial (−6.85 (95%CI; -18.20 to 4.49) %, p = 0.37) and were statistically significantly less accurate than multisensor devices (−3.64 (95%CI; -8.97 to 1.70) %, p<0.001). TEE was underestimated during slow walking speeds in 69% of the lab validation studies compared to 37%, 30% and 37% of the studies during intermediate, fast walking speed and running, respectively. The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome. Triaxial and multisensor devices tend to be more valid monitors. Since activity monitors are less accurate at slow walking speeds and information about validated activity monitors in chronic disease populations is lacking, proper validation studies in these populations are needed prior to their inclusion in clinical trials.

Validity of physical activity monitors during daily life in patients with COPD

Symptoms during physical activity and physical inactivity are hallmarks of chronic obstructive pulmonary disease (COPD). Our aim was to evaluate the validity and usability of six activity monitors in patients with COPD against the doubly labelled water (DLW) indirect calorimetry method. 80 COPD patients (mean±sd age 68±6 years and forced expiratory volume in 1 s 57±19% predicted) recruited in four centres each wore simultaneously three or four out of six commercially available monitors validated in chronic conditions for 14 consecutive days. A priori validity criteria were defined. These included the ability to explain total energy expenditure (TEE) variance through multiple regression analysis, using TEE as the dependent variable with total body water (TBW) plus several physical activity monitor outputs as independent variables; and correlation with activity energy expenditure (AEE) measured by DLW. The Actigraph GT3X (Actigraph LLC, Pensacola, FL, USA), and DynaPort MoveMonitor (McRoberts BV, The Hague, the Netherlands) best explained the majority of the TEE variance not explained by TBW (53% and 70%, respectively) and showed the most significant correlations with AEE (r=0.71, p<0.001 and r=0.70, p<0.0001, respectively). The results of this study should guide users in choosing valid activity monitors for research or for clinical use in patients with chronic diseases such as COPD. This study validates six activity monitors in the field against indirect calorimetry (DLW) in patients with COPD http://ow.ly/o9VIE

Daily physical activity in subjects with newly diagnosed COPD

Rationale Information about daily physical activity levels (PAL) in subjects with undiagnosed chronic obstructive pulmonary disease (COPD) is scarce. This study aims to assess PA and to investigate the associations between PA and clinical characteristics in subjects with newly diagnosed COPD. Methods Fifty-nine subjects with a new spirometry-based diagnosis of mild (n=38) and moderate (n=21) COPD (63±6 years, 68% male) were matched with 65 smoking controls (62±7 years, 75% male). PA (daily steps, time spent in moderate-to-vigorous intense physical activities (MVPA) and PAL) was measured by accelerometry. Dyspnoea, complete pulmonary function tests, peripheral muscle strength and exercise capacity served as clinical characteristics. Results PA was significantly lower in COPD versus smoking controls (7986±2648 vs 9765±3078 steps, 64 (27–120) vs 110 (55–164) min of MVPA, 1.49±0.21 vs 1.62±0.24 PAL respectively, all p<0.05). Subjects with COPD with either mild symptoms of dyspnoea (mMRC 1), those with lower diffusion capacity (TL,co), low 6 min walking distance (6MWD) or low maximal oxygen uptake (VO2 peak) had significantly lower PA. Multiple regression analysis identified 6 MWD and TL,co as independent predictors of PA in COPD. Conclusions The reduction in PA starts early in the disease, even when subjects are not yet diagnosed with COPD. Inactivity is more pronounced in subjects with mild symptoms of dyspnoea, lower levels of diffusion capacity and exercise capacity.

Validation of two activity monitors in patients with COPD

Physical activity in daily life is increasingly used as an outcome measure in chronic respiratory disease.1 Valid and user-friendly instruments are needed to quantify daily activity.1 2 The DynaPort activity monitor (McRoberts, The Hague, The Netherlands) has been validated and used in patients with chronic obstructive pulmonary disease (COPD).3 4 The device is, however, technically difficult to handle and, due to its size (12.5×9.5×3 cm, 375 g), it is always noticeable. We therefore validated two smaller activity monitors in a sample of 10 patients with COPD (mean (SD) forced expiratory volume in 1 s 49 (16)% predicted; mean (SD) age 65 (8) years) and 10 healthy elderly volunteers (mean (SD) age 65 (9) years). Detailed characteristics of the study subjects are summarised in table 1 in the online supplement. All patients simultaneously wore the DynaPort, the SenseWear Pro (SenseWear, Body Media, Pittsburgh, USA) activity monitor (8.5×5.0×1.5 cm, 85 g), …

Exercise training after lung transplantation improves participation in daily activity: a randomized controlled trial.

The effects of exercise training after lung transplantation have not been studied in a randomized controlled trial so far. We investigated whether 3 months of supervised training, initiated immediately after hospital discharge, improve functional recovery and cardiovascular morbidity of patients up to 1 year after lung transplantation. Patients older than 40 years, who experienced an uncomplicated postoperative period, were eligible for this single blind, parallel group study. Sealed envelopes were used to randomly allocate patients to 3 months of exercise training (n = 21) or a control intervention (n = 19). Minutes of daily walking time (primary outcome), physical fitness, quality of life and cardiovascular morbidity were compared between groups adjusting for baseline assessments in a mixed models analysis. After 1 year daily walking time in the treated patients (n = 18) was 85 ± 27 min and in the control group (n = 16) 54 ± 30 min (adjusted difference 26 min [95%CI 8–45 min, p = 0.006]). Quadriceps force (p = 0.001), 6‐minute walking distance (p = 0.002) and self‐reported physical functioning (p = 0.039) were significantly higher in the intervention group. Average 24 h ambulatory blood pressures were significantly lower in the treated patients (p ≤ 0.01). Based on these results patients should be strongly encouraged to participate in an exercise training intervention after lung transplantation.

Effectiveness of exercise training in patients with COPD: the role of muscle fatigue

The improvement in exercise performance in response to exercise training varies greatly from one patient with chronic obstructive pulmonary disease to another. It is possible that in a portion of patients the muscle stimulus applied during exercise training is insufficient to elicit training effects. We investigated whether patients presenting quadriceps contractile fatigue after training have more favourable effects of a rehabilitation programme. 46 patients followed a 3-month high-intensity exercise training programme. Exercise capacity, quadriceps force and quality of life were measured before and after the programme. Exercise training-induced quadriceps contractile fatigue was assessed after 1 month of rehabilitation with magnetic stimulation. A fall in quadriceps force of ≥15%, 15 min after training was considered as significant fatigue. 29 (63%) out of 46 patients developed significant fatigue. Patients with fatigue had a higher increase in 6-min walk distance (median (interquartile range) 57 (47–103) m versus 17 (-7–46) m; p=0.0023) and Chronic Respiratory Disease Questionnaire score (mean±sd 22±12 points versus 14±12 points; p=0.028) after the training programme compared with patients without fatigue. Improvements in quadriceps force and maximal exercise capacity were similar in both subgroups. Patients who develop quadriceps contractile fatigue during exercise training show greater training effects in terms of functional exercise capacity and health-related quality of life.

Standardizing the Analysis of Physical Activity in Patients With COPD Following a Pulmonary Rehabilitation Program

BACKGROUND: There is a wide variability in measurement methodology of physical activity. This study investigated the effect of different analysis techniques on the statistical power of physical activity outcomes after pulmonary rehabilitation. METHODS: Physical activity was measured with an activity monitor armband in 57 patients with COPD (mean ± SD age, 66 ± 7 years; FEV1, 46 ± 17% predicted) before and after 3 months of pulmonary rehabilitation. The choice of the outcome (daily number of steps [STEPS], time spent in at least moderate physical activity [TMA], mean metabolic equivalents of task level [METS], and activity time [ACT]), impact of weekends, number of days of assessment, postprocessing techniques, and influence of duration of daylight time (DT) on the sample size to achieve a power of 0.8 were investigated. RESULTS: The STEPS and ACT (1.6-2.3 metabolic equivalents of task) were the most sensitive outcomes. Excluding weekends decreased the sample size for STEPS (83 vs 56), TMA (160 vs 148), and METS (251 vs 207). Using 4 weekdays (STEPS and TMA) or 5 weekdays (METS) rendered the lowest sample size. Excluding days with < 8 h wearing time reduced the sample size for STEPS (56 vs 51). Differences in DT were an important confounder. CONCLUSIONS: Changes in physical activity following pulmonary rehabilitation are best measured for 4 weekdays, including only days with at least 8 h of wearing time (during waking hours) and considering the difference in DT as a covariate in the analysis. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00948623; URL: www.clinicaltrials.gov

Physical activity in daily life 1 year after lung transplantation.

BACKGROUND Reduced physical fitness has been reported to occur after lung transplantation. Pre- and post-transplant factors, including an inactive lifestyle, have been proposed as possible causes. However, daily physical activity has not been objectively assessed so far in lung recipients. The purpose of this study was to objectively measure daily physical activity in lung recipients. METHODS Twenty-two clinically stable patients with single (n = 7) and bilateral lung grafts (n = 15) underwent measurements of physical activity with activity monitors at least 12 months after surgery. Results were compared with findings from 22 healthy, age- and gender-matched control subjects. RESULTS Substantial and statistically significant differences in daily activity were observed. Steps, standing time and moderate-intensity activity of lung recipients were reduced by 42%, 29% and 66%, respectively, relative to controls. Daily sedentary time was increased by 30%. Daily steps correlated with self-reported physical functioning (r = 0.81), 6-minute walk distance (r = 0.68), quadriceps force (r = 0.66) and maximum workload (r = 0.63). CONCLUSIONS This study has shown for the first time that daily activity is substantially reduced after lung transplantation and related to measures of physical fitness and health-related quality of life. Future studies need to examine whether physical activity can be modified to improve functional recovery after lung transplantation.