Let's get physical: Aerobic capacity, muscle strength, and muscle endurance after pediatric heart transplantation.

BACKGROUND: Pediatric heart (HTx) and kidney transplant (KTx) recipients may have lower physical fitness than healthy children. This study sought to quantify fitness levels in transplant recipients, investigate associations to clinical factors and quality of life, and identify whether a quick, simple wall-sit test is feasible as a surrogate for overall fitness for longitudinal assessment. METHODS: Aerobic capacity (6-min walk test, 6MWT), normalized muscle strength, muscle endurance, physical activity questionnaire (PAQ), and quality of life (PedsQL™) were prospectively assessed in transplanted children and matched healthy controls. RESULTS: Twenty-two HTx were compared to 20 controls and 6 KTx. 6MWT %predicted was shorter in HTx (87.2 [69.9-118.6] %) than controls (99.9 [80.4-120] %), but similar to KTx (90.3 [78.6-115] %). Muscle strength was lower in HTx deltoids (6.15 [4.35-11.3] kg/m2) and KTx quadriceps (9.27 [8.65-19.1] kg/m2) versus controls. Similarly, muscle endurance was lower in HTx push-ups (28.6 [0-250] %predicted), KTx push-ups (8.35 [0-150] %predicted), HTx curl-ups (115 [0-450] %predicted), and KTx wall-sit time (18.5 [10.0-54.0] s) than controls. In contrast to HTx with only 9%, all KTx were receiving steroid therapy. The wall-sit test significantly correlated with other fitness parameters (normalized quadriceps strength R = .31, #push-ups R = .39, and #curl-ups R = .43) and PedsQL™ (R = .36). CONCLUSIONS: Compared to controls, pediatric HTx and KTx have similarly lower aerobic capacity, but different deficits in muscle strength, likely related to steroid therapy in KTx. The convenient wall-sit test correlates with fitness and reported quality of life, and thus could be a useful easy routine for longitudinal assessment.

Adverse Events During Submaximal Aerobic Exercise Testing in People With Subacute Stroke: A Scoping Review.

BACKGROUND AND PURPOSE: Concern for adverse cardiovascular events and limited guidance regarding how to conduct aerobic exercise (AEx) testing for individuals poststroke are key barriers to implementation by physical therapists in stroke rehabilitation. This study aimed to describe the nature and safety of submaximal AEx testing protocols for people with subacute stroke (PwSS) and the nature of comorbidity of PwSS who underwent submaximal AEx testing. METHODS: We conducted a scoping review and searched MEDLINE, EMBASE, PsycINFO, CINAHL, and SPORTDiscus from inception to October 29, 2020. Studies involving submaximal AEx testing with PwSS, reporting on participant comorbidity and on adverse events during testing, were eligible. Two reviewers independently conducted title and abstract and full-text screening. One reviewer extracted data; a second reviewer verified data. RESULTS: Thirteen studies involving 452 participants and 19 submaximal AEx testing protocols (10 field test, 7 incremental, and 2 constant load) were included. Hypertension (41%), diabetes (31%), and dyslipidemia (27%) were the most common comorbidities reported. No protocols resulted in a serious adverse event. The most common test termination criterion was a heart rate (HR) limit (9 protocols); a limit of 85% age-predicted maximal HR (APM-HR) most frequently reported. Average APM-HR achieved, computed using mean age and mean peak HR, ranged from 59% to 88% across 13 protocols. DISCUSSION AND CONCLUSION: Diverse submaximal AEx testing protocols with conservative test termination criteria can be safely implemented with PwSS. Results can inform clinical practice guidelines and address physical therapists' concerns with the occurrence of serious adverse events during submaximal AEx testing.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A430 ).

Intermittent neck flexion induces greater sternocleidomastoid deoxygenation than inspiratory threshold loading.

PURPOSE: To compare deoxygenation of the sternocleidomastoid, scalenes, and diaphragm/intercostals (Dia/IC) during submaximal intermittent neck flexion (INF) versus submaximal inspiratory threshold loading (ITL) in healthy adults. METHODS: Fourteen participants performed a randomized, cross-over, repeated measures design. After evaluation of maximal inspiratory pressures (MIP) and maximum voluntary contraction (MVC) for isometric neck flexion, participants were randomly assigned to submaximal ITL or INF until task failure. At least 2 days later, they performed the submaximal exercises in the opposite order. ITL or INF targeted 50 ± 5% of the MIP or MVC, respectively, until task failure. Near-infrared spectroscopy (NIRS) was applied to evaluate changes of deoxy-hemoglobin (ΔHHb), oxy-hemoglobin (ΔO2Hb), total hemoglobin (ΔtHb), and tissue saturation of oxygen (StO2) of the sternocleidomastoid, scalenes, and Dia/IC. Breathlessness and perceived exertion were evaluated using Borg scales. RESULTS: Initially during INF, sternocleidomastoid HHb slope was greatest compared to the scalenes and Dia/IC. At isotime (6.5-7 min), ΔtHb (a marker of blood volume) and ΔO2Hb of the sternocleidomastoid were higher during INF than ITL. Sternocleidomastoid HHb, O2Hb, and tHb during INF also increased at quartile and task failure timepoints. In contrast, scalene ΔO2Hb was higher during ITL than INF at isotime. Further, Dia/IC O2Hb and tHb increased during ITL at the third quartile and at task failure. Borg scores were lower at task failure during INF compared to ITL. CONCLUSION: Intermittent INF induces significant metabolic activity of the sternocleidomastoid and a lower perception of effort, which may provide an alternative inspiratory muscle training approach for mechanically ventilated patients.

Using Physiological Markers to Assess Comfort during Neuromuscular Electrical Stimulation Induced Muscle Contraction in a Virtually Guided Environment: Pilot Study for a Path toward Combating ICU-Acquired Weakness.

We assessed the feasibility of implementing a virtually guided Neuromuscular Electrical Stimulation (NMES) protocol over the tibialis anterior (TA) muscle while collecting heart rate (HR), Numeric Pain Rating Scale (NPRS), and quality of contraction (QoC) data. We investigated if HR, NPRS, and QoC differ ON and OFF the TA motor point and explored potential relationships between heart rate variability (HRV) and the NPRS. Twelve healthy adults participated in this cross-sectional study. Three NMES trials were delivered ON and OFF the TA motor point. HR, QoC, and NPRS data were collected. There was no significant difference in HRV ON and OFF the motor point (p > 0.05). The NPRS was significantly greater OFF the motor point (p < 0.05). The QoC was significantly different between motor point configurations (p < 0.05). There was no correlation between the NPRS and HRV (p > 0.05, r = -0.129). We recommend non-electrical methods of measuring muscle activity for future studies. The NPRS and QoC can be administered virtually. Time-domain HRV measures could increase the validity of the protocol. The variables should be explored further virtually to enhance the protocol before eventual ICU studies.

Clinical implications of frailty assessed in hospitalized patients with acute-exacerbation of interstitial lung disease.

BACKGROUND: Approximately 50% of patients with interstitial lung disease (ILD) experience frailty, which remains unexplored in acute exacerbations of ILD (AE-ILD). A better understanding may help with prognostication and resource planning. We evaluated the association of frailty with clinical characteristics, physical function, hospital outcomes, and post-AE-ILD recovery. METHODS: Retrospective cohort study of AE-ILD patients (01/2015-10/2019) with frailty (proportion ≥0.25) on a 30-item cumulative-deficits index. Frail and non-frail patients were compared for pre- and post-hospitalization clinical characteristics, adjusted for age, sex, and ILD diagnosis. One-year mortality, considering transplantation as a competing risk, was analysed adjusting for age, frailty, and Charlson Comorbidity Index (CCI). RESULTS: 89 AE-ILD patients were admitted (median: 67 years, 63% idiopathic pulmonary fibrosis). 31 were frail, which was associated with older age, greater CCI, lower 6-min walk distance, and decreased independence pre-hospitalization. Frail patients had more major complications (32% vs 10%, p = .01) and required more multidisciplinary support during hospitalization. Frailty was not associated with 1-year mortality (HR: 0.97, 95%CI: [0.45-2.10]) factoring transplantation as a competing risk. CONCLUSIONS: Frailty was associated with reduced exercise capacity, increased comorbidities and hospital complications. Identifying frailty may highlight those requiring additional multidisciplinary support, but further study is needed to explore whether frailty is modifiable with AE-ILD.

Methodological and Clinimetric Evaluation of Inspiratory Respiratory Muscle Ultrasound in the Critical Care Setting: A Systematic Review and Meta-Analysis.

OBJECTIVE: Significant variations exist in the use of respiratory muscle ultrasound in intensive care with no society-level consensus on the optimal methodology. This systematic review aims to evaluate, synthesize, and compare the clinimetric properties of different image acquisition and analysis methodologies. DATA SOURCES: Systematic search of five databases up to November 24, 2021. STUDY SELECTION: Studies were included if they enrolled at least 50 adult ICU patients, reported respiratory muscle (diaphragm or intercostal) ultrasound measuring either echotexture, muscle thickness, thickening fraction, or excursion, and evaluated at least one clinimetric property. Two independent reviewers assessed titles, abstracts, and full text against eligibility. DATA EXTRACTION: Study demographics, ultrasound methodologies, and clinimetric data. DATA SYNTHESIS: Sixty studies, including 5,025 patients, were included with 39 studies contributing to meta-analyses. Most commonly measured was diaphragm thickness (DT) or diaphragm thickening fraction (DTF) using a linear transducer in B-mode, or diaphragm excursion (DE) using a curvilinear transducer in M-mode. There are significant variations in imaging methodology and acquisition across all studies. Inter- and intrarater measurement reliabilities were generally excellent, with the highest reliability reported for DT (ICC, 0.98; 95% CI, 0.94-0.99). Pooled data demonstrated acceptable to excellent accuracy for DT, DTF, and DE to predicting weaning outcome after 48 to 72 hours postextubation (DTF AUC, 0.79; 95% CI, 0.73-0.85). DT imaging was responsive to change over time. Only three eligible studies were available for intercostal muscles. Intercostal thickening fraction was shown to have excellent accuracy of predicting weaning outcome after 48-hour postextubation (AUC, 0.84; 95% CI, 0.78-0.91). CONCLUSIONS: Diaphragm muscle ultrasound is reliable, valid, and responsive in ICU patients, but significant variation exists in the imaging acquisition and analysis methodologies. Future work should focus on developing standardized protocols for ultrasound imaging and consider further research into the role of intercostal muscle imaging.

European Society of Organ Transplantation (ESOT) Consensus Statement on Prehabilitation for Solid Organ Transplantation Candidates.

There is increasingly growing evidence and awareness that prehabilitation in waitlisted solid organ transplant candidates may benefit clinical transplant outcomes and improve the patient's overall health and quality of life. Lifestyle changes, consisting of physical training, dietary management, and psychosocial interventions, aim to optimize the patient's physical and mental health before undergoing surgery, so as to enhance their ability to overcome procedure-associated stress, reduce complications, and accelerate post-operative recovery. Clinical data are promising but few, and evidence-based recommendations are scarce. To address the need for clinical guidelines, The European Society of Organ Transplantation (ESOT) convened a dedicated Working Group "Prehabilitation in Solid Organ Transplant Candidates," comprising experts in physical exercise, nutrition and psychosocial interventions, to review the literature on prehabilitation in this population, and develop recommendations. These were discussed and voted upon during the Consensus Conference in Prague, 13-15 November 2022. A high degree of consensus existed amongst all stakeholders including transplant recipients and their representatives. Ten recommendations were formulated that are a balanced representation of current published evidence and real-world practice. The findings and recommendations of the Working Group on Prehabilitation for solid organ transplant candidates are presented in this article.

Glucocorticoid-induced myopathy in people with asthma: a systematic review.

OBJECTIVES: To review the current literature on the evidence and the underlying characteristics of glucocorticoids (type, dosage, and duration) associated with myopathy in asthma. DATA SOURCES: Four electronic databases were searched to October 19, 2020. STUDY SELECTION: Inclusion criteria: adults or adolescents with asthma, taking systemic glucocorticoids, and measures of muscle impairments. RESULTS: Nine studies met the eligibility criteria. The methodologic quality of most studies was fair or good. Two studies reported significantly lower inspiratory muscle function in outpatients taking daily oral glucocorticoids (≥10 mg), but one study reported no such difference. No differences was found in limb muscle strength in one study. Only 11-36% patients with acute exacerbation taking glucocorticoids intravenously suffered from limb muscle weakness during/after critical care admissions. Two studies reported significant associations between dosage of oral glucocorticoid use and inspiratory and limb muscle function, whereas seven studies did not find any significant correlations among the characteristics of systemic glucocorticoids and myopathy. Two studies comparing people with non-glucocorticoid dependent asthma taking inhaled glucocorticoid and healthy people did not find any significant differences in their inspiratory muscle strength and endurance. CONCLUSIONS: There were limited studies and inconsistent results on glucocorticoid-induced myopathy in people with asthma, and its association with the characteristics of glucocorticoids use. We recommended future studies should use a commonly accepted operational definition of myopathy, utilize a cohort study design, measure the cumulative dosage of glucocorticoids, and integrate possible confounding factors in the analysis.

Validation of High-Resolution peripheral Quantitative Computed Tomography-Derived Achilles Tendon Properties Against Diagnostic Ultrasound.

OBJECTIVES: 1) To assess the precision of high resolution peripheral quantitative computed tomography (HR-pQCT)-derived Achilles tendon (AT) cross-sectional area (HR AT-CSA) and density, and 2) to validate HR AT-CSA against ultrasound-derived AT-CSA (US AT-CSA). METHODS: Women and men (≥50 years) had HR-pQCT (0.082mm isotropic) and US scans (B-mode) performed on the non-dominant ankle. Linear regression and Bland-Altman analyses assessed systematic differences between HR-pQCT and US-derived AT-CSA. Precision measured by % root mean square coefficients of variation (%RMSCV) and agreement by type 2,1 intraclass correlation coefficients (ICC2,1), were determined for test-retest US AT-CSA scans, and analysis-reanalysis of 30 HR-pQCT and US images. RESULTS: Among 44 participants, HR and US AT-CSA were strongly correlated (R2=0.84, p<0.01, B=1.05[0.90-1.19]), with no differences between modalities (p=0.37). Bland-Altman analysis revealed minimal systematic bias (-0.7mm2[-10.7-9.3]; 1.3%) between HR-pQCT and US-derived AT-CSA with smaller AT-CSA values showing larger inter-modality differences (R2=0.098, B=-0.137 [-0.268--0.008], p=0.039). US AT-CSA demonstrated excellent test-retest precision (ICC2,1=0.998, %RMSCV=1.04%). Analysis-reanalysis of HR-pQCT AT-density and both HR-pQCT and US AT-CSA displayed ICC2,1 above 0.95 and %RMSCV within 3%. CONCLUSION: HR-pQCT can examine AT-morphometry with acceptable analytical precision. Future studies should explore these metrics' association with functional outcomes and ankle-bone structural and mechanical properties.

Comparison of quadriceps muscle size and quality in adults with cystic fibrosis with different severities of cystic fibrosis transmembrane conductance regulator protein dysfunction.

BACKGROUND: Cystic fibrosis (CF) is characterized by CF transmembrane conductance regulator (CFTR) dysfunction. CFTR protein is expressed in human skeletal muscle; however, its impact on skeletal muscle is unknown. The objectives of this study were to compare quadriceps muscle size and quality between adults with various severities of CFTR protein dysfunction. METHODS: We conducted a prospective, cross-sectional study comparing 34 adults with severe versus 18 with mild CFTR protein dysfunction, recruited from a specialized CF centre. Ultrasound images of rectus femoris cross-sectional area (RF-CSA) and quadriceps layer thickness for muscle size, and rectus femoris echogenicity (RF-ECHO) (muscle quality) were obtained. Multivariable linear regression models were developed using purposeful selection technique. RESULTS: People with severe CFTR protein dysfunction had larger RF-CSA by 3.22 cm2, 95% CI (1.03, 5.41) cm2, p=.0049], after adjusting for oral corticosteroid use and Pseudomonas aeruginosa colonization. However, a sensitivity analysis indicated that the result was influenced by the specific confounders being adjusted for in the model. We did not find any significant differences in quadriceps layer thickness or RF-ECHO between the two groups. CONCLUSION: We found no differential impact of the extent of diminished CFTR protein activity on quadriceps muscle size or quality in our study cohort. Based on these findings, CFTR mutation status cannot be used differentiate leg muscle size or quality in people with CF.

Computed tomography-based body composition measures in COPD and their association with clinical outcomes: A systematic review.

BACKGROUND: Computed tomography (CT) is commonly utilized in chronic obstructive pulmonary disease (COPD) for lung cancer screening and emphysema characterization. Computed tomography-morphometric analysis of body composition (muscle mass and adiposity) has gained increased recognition as a marker of disease severity and prognosis. This systematic review aimed to describe the CT-methodology used to assess body composition and identify the association of body composition measures and disease severity, health-related quality of life (HRQL), cardiometabolic risk factors, respiratory exacerbations, and survival in patients with COPD. METHODS: Six databases were searched (inception-September 2021) for studies evaluating adult COPD patients using thoracic or abdominal CT-muscle or adiposity body composition measures. The systematic review was conducted in accordance with the PRISMA guidelines. RESULTS: Twenty eight articles were included with 15,431 COPD patients, across all GOLD stages with 77% males, age range (mean/median 59-78 years), and BMI range 19.8-29.3 kg/m2. There was heterogeneity in assessment of muscle mass and adiposity using thoracic (n = 22) and abdominal (n = 8) CT-scans, capturing different muscle groups, anatomic locations, and adiposity compartments (visceral, subcutaneous, and epicardial). Low muscle mass and increased adiposity were associated with increased COPD severity measures (lung function, exercise capacity, dyspnea) and lower HRQL, but were not consistent across studies. Increased visceral adiposity (n = 6) was associated with cardiovascular disease or risk factors (hypertension, hyperlipidemia, and diabetes). Low muscle CSA was prognostic of respiratory exacerbations or mortality in three of six studies, whereas the relationship with increased intermuscular adiposity and greater mortality was only observed in one of three studies. CONCLUSION: There was significant variability in CT-body composition measures. In several studies, low muscle mass was associated with increased disease severity and lower HRQL, whereas adiposity with cardiovascular disease/risk factors. Given the heterogeneity in body composition measures and clinical outcomes, the prognostic utility of CT-body composition in COPD requires further study.

Associations Between Lower Limb Isometric Torque, Isokinetic Torque, and Explosive Force With Phases of Reactive Stepping in Young, Healthy Adults.

This study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate-derived timing measures of reactive stepping. Nineteen young, healthy adults responded to 6 perturbations using an anterior lean-and-release system. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = -.582, P = .009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = -.459, P = .048); however, this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (P > .025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.

User-centered design features for digital health applications to support physical activity behaviors in solid organ transplant recipients: A qualitative study.

INTRODUCTION: Digital health tools may be effective in engaging solid organ transplant (SOT) recipients in physical activity (PA). This study examined the perspectives of SOT recipients regarding PA, and desired features for digital health tools. METHODS: Semi-structured interviews were used to explore perspectives of SOT recipients about barriers and motivators to physical activity, and core features of a digital health tool to support PA. Interviews were analyzed via thematic analysis. RESULTS: Participants included 21 SOT recipients (11 men, 10 women, 21-78 years, 1.5-16 years post-transplant) from various organ groups (four heart, five kidney, five liver, three lung, and four multi-organ). Barriers to PA included risk aversion, managing non-linear health trajectories, physical limitations and lack of access to appropriate fitness training. Facilitators of PA included desire to live long and healthy lives, renewed physical capabilities, access to appropriate fitness guidelines and facilities. Desired features of a digital health tool included a reward system, affordability, integration of multiple functions, and the ability to selectively share information with healthcare professionals and peers. CONCLUSIONS: SOT recipients identified the desired features of a digital health tool, which may be incorporated into future designs of digital and mobile health applications to support PA in SOT recipients.

The effects of exercise training in adult solid organ transplant recipients: A systematic review and meta-analysis.

Reduced exercise capacity can predispose solid organ transplant (SOT) recipients to higher risk of diabetes, cardiovascular complications, and mortality and impact their quality of life. This systematic review and meta-analysis investigated the effects of exercise training (versus no training) in adult SOT recipients. We conducted an electronic search of randomized controlled trials reporting on exercise interventions in SOT recipients. Primary outcomes were exercise capacity, quadriceps muscle strength, and health-related quality of life (HRQoL). Twenty-nine articles met the inclusion criteria. In 24 studies, there were either high risk of bias or some concerns about the potential risk of bias. There was an increase in exercise capacity (VO2 peak) (SMD: 0.40; 95%CI 0.22-0.57; P = 0.0) and quadriceps muscle strength (SMD: 0.38; 95%CI 0.16-0.60; P = 0.001) in the exercise vs control groups. There were also improvements in several domains of the SF-36. Diastolic blood pressure improved in the exercise group compared to controls (SMD: -0.22; 95%CI -0.41-0.03; P = 0.02). Despite the considerable variation in exercise training characteristics and high risk of bias in the included studies, exercise training improved maximal exercise capacity, quadriceps muscle strength, HRQoL, and diastolic blood pressure and should be an essential part of the post-transplant care.

Pre-transplant short physical performance battery: Response to pre-habilitation and relationship to pre- and early post-lung-transplant outcomes.

PURPOSE: To evaluate whether the short physical performance battery (SPPB) pre-lung transplant (LTx) was responsive to pre-habilitation and predicted pre- and early post-transplant outcomes. METHODS: A retrospective study of LTx candidates accepted for transplant between 2016 and 2017. SPPB was categorized as frail/pre-frail (≤9/12) and non-frail (≥10/12). RESULTS: 150 patients had LTx assessment SPPB data (53% male, 61 [52-67] years, 59% had interstitial lung disease (ILD), 26% frail/pre-frail). 131 (87%) underwent transplant by December 31, 2018. Adjusting for age, sex, diagnosis and Canadian transplant listing urgency, and frailty/pre-frailty at LTx assessment was associated with a lower 6MWD pre-transplant [-89 meters 95%CI (-125 to -53), P < .0001]. 62 patients underwent six weeks of pre-habilitation. SPPB increased (11 [10-12) vs. 12 [11-12], P = .01) reflected in the chair stand component (11.4 ± 4.4 vs. 9.8 ± 2.8 seconds, P = .007), with larger improvements in the frail/pre-frail group. A frail/pre-frail SPPB closest to the time of transplant was associated with a lower 6MWD [-77 m 95%CI (-128 to -25), P = .004] but not with hospital length of stay or gait aid use three months post-transplant. CONCLUSIONS: Frailty/pre-frailty was associated with a decreased 6MWD pre- and post-transplant. The SPPB increased following pre-habilitation, which may reflect increased lower extremity strength.

Clinical outcomes associated with computed tomography-based body composition measures in lung transplantation: a systematic review.

Computed tomography (CT) is gaining increased recognition in the assessment of body composition in lung transplant (LTx) candidates as a prognostic marker of post-transplant outcomes. This systematic review was conducted to describe the methodology of CT measures of body composition used in LTx patients and its association with post-transplant outcomes. Six databases were searched (inception-April 2020) for studies of adult LTx patients with thoracic or abdominal CT measures [muscle cross-sectional area (CSA) and/or adiposity]. Thirteen articles were included with 1911 LTx candidates, 58% males, mean age range (48-61 years) and body mass index of 21.0-26.1 kg/m2 . Several methods were utilized using thoracic or abdominal CT scans to assess skeletal muscle (n = 11) and adiposity (n = 4) at various anatomic locations (carina, thoracic, and lumbar vertebrae), differing muscle groups, and adipose tissue compartments. Low muscle mass was associated with adverse outcomes in 6/11 studies, including longer mechanical ventilation days (n = 2), intensive care (n = 2) and hospital stay (n = 2), and mortality (n = 4). Greater subcutaneous and mediastinal fat were associated with increased risk of primary graft dysfunction (n = 2), but implications of adiposity on survival were variable across four studies. Further standardization of CT body composition assessments is needed to assess the prognostic utility of these measures on LTx outcomes.

The effect of bed rest on balance control in healthy adults: A systematic scoping review.

The objective of this study was to determine the effect of bed rest on balance control and the mechanisms responsible for these changes. Searches were conducted in six databases. Studies had to be conducted on healthy adults who were subjected to bed rest (≥5 days), with balance control measures obtained before and after bed rest in order to be included. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After screening 9,785 articles, 18 were included for qualitative synthesis. Fifteen studies found decrements in at least one balance control measure following bed rest, either compared to baseline or controls, with eight studies observing impairments in >50% of their balance control measures. Of the 14 studies that included an intervention, four (mechanical stimuli, lower-body negative pressure, and training targeting strength, balance and/or aerobic capacity) successfully offset the majority of balance control deficits and targeted the musculoskeletal and cardiovascular systems. The findings of this review support bed rest negatively affecting balance control in healthy individuals. In clinical populations, these deficits may be further accentuated due to various comorbidities that impact balance control systems. PROSPERO Registration: CRD42018098887.

Intensive Care Unit-Acquired Weakness: Not just Another Muscle Atrophying Condition.

Intensive care unit-acquired weakness (ICUAW) occurs in critically ill patients stemming from the critical illness itself, and results in sustained disability long after the ICU stay. Weakness can be attributed to muscle wasting, impaired contractility, neuropathy, and major pathways associated with muscle protein degradation such as the ubiquitin proteasome system and dysregulated autophagy. Furthermore, it is characterized by the preferential loss of myosin, a distinct feature of the condition. While many risk factors for ICUAW have been identified, effective interventions to offset these changes remain elusive. In addition, our understanding of the mechanisms underlying the long-term, sustained weakness observed in a subset of patients after discharge is minimal. Herein, we discuss the various proposed pathways involved in the pathophysiology of ICUAW, with a focus on the mechanisms underpinning skeletal muscle wasting and impaired contractility, and the animal models used to study them. Furthermore, we will explore the contributions of inflammation, steroid use, and paralysis to the development of ICUAW and how it pertains to those with the corona virus disease of 2019 (COVID-19). We then elaborate on interventions tested as a means to offset these decrements in muscle function that occur as a result of critical illness, and we propose new strategies to explore the molecular mechanisms of ICUAW, including serum-related biomarkers and 3D human skeletal muscle culture models.

One-Year Outcomes in Caregivers of Critically Ill Patients.

BACKGROUND: Few resources are available to support caregivers of patients who have survived critical illness; consequently, the caregivers' own health may suffer. We studied caregiver and patient characteristics to determine which characteristics were associated with caregivers' health outcomes during the first year after patient discharge from an intensive care unit (ICU). METHODS: We prospectively enrolled 280 caregivers of patients who had received 7 or more days of mechanical ventilation in an ICU. Using hospital data and self-administered questionnaires, we collected information on caregiver and patient characteristics, including caregiver depressive symptoms, psychological well-being, health-related quality of life, sense of control over life, and effect of providing care on other activities. Assessments occurred 7 days and 3, 6, and 12 months after ICU discharge. RESULTS: The caregivers' mean age was 53 years, 70% were women, and 61% were caring for a spouse. A large percentage of caregivers (67% initially and 43% at 1 year) reported high levels of depressive symptoms. Depressive symptoms decreased at least partially with time in 84% of the caregivers but did not in 16%. Variables that were significantly associated with worse mental health outcomes in caregivers were younger age, greater effect of patient care on other activities, less social support, less sense of control over life, and less personal growth. No patient variables were consistently associated with caregiver outcomes over time. CONCLUSIONS: In this study, most caregivers of critically ill patients reported high levels of depressive symptoms, which commonly persisted up to 1 year and did not decrease in some caregivers. (Funded by the Canadian Institutes of Health Research and others; ClinicalTrials.gov number, NCT00896220.).

Impaired cardiac autonomic response in lung transplant patients: A retrospective cohort study.

BACKGROUND: Cardiac autonomic dysfunction (AD) is associated with adverse prognosis in lung disease; however, its implications in lung transplantation have not been previously described. This study evaluated the prevalence of AD in lung transplant (LTx) candidates, its determinants, prognostic implications, and prevalence post-transplant. METHODS: Retrospective one-year study of 103 LTx candidates with AD assessed using heart rate (HR) from the six-minute walk test (6MWT). Impaired chronotropic response index (CRI) was defined as <80% age-adjusted HR during 6MWT. Abnormal HR recovery (HRR) was categorized as reduction in HR ≤ 12 beats/minute after the first minute of 6MWT cessation. RESULTS: Abnormal CRI and HRR were observed in 94% and 76% of patients, respectively. A lower CRI was associated with obstructive lung disease and lower estimated aerobic capacity. CRI was independently associated with 6MW distance [12 m per 10% CRI, P = 0.03], but not with post-transplant cardiovascular events, hospital stay, or one-year mortality. At 3 months post-transplant, no improvement was observed in CRI (99%, n = 66/67, P = 0.25) or HRR (88%, n = 36/41, P = 0.12). CONCLUSION: Cardiac AD was prevalent in LTx candidates and recipients, with chronotropic incompetence a modest contributor to exercise intolerance pretransplant. Further study may help determine whether direct autonomic measures such as HR variability may be more prognostic of LTx outcomes.