Physical activity and aerobic fitness in children after liver transplantation

Physical function in children and adolescents pre- and 1-year post-liver transplant

BACKGROUND

Several studies describe poorer motor developmental motor outcomes post-liver transplant (LT) in younger children. Limited studies examine physical function in older children and adolescents pre- and post-LT.

METHODS

Retrospective review of standard of care physical function outcome measures pre- and 1-year post-LT in children ≥6 years at LT. Measures include: 6-minute walk test (6MWT), grip strength, Bruininks-Oseretsky Test of Motor Proficiency-2 (BOT-2) components, Physical Activity Questionnaire (PAQ), and Paediatric Quality of Life Multidimensional Fatigue Scale. Association of medical variables with outcomes was explored.

RESULTS

The study cohort included 23 (8 male, median (interquartile range) age 11.67 (8.25, 13.92) years at LT) participants. Top two primary diagnoses included biliary atresia (30.4%) and fulminant hepatic failure (21.7%). At 1-year post-LT, over one-third (36%) were overweight or obese. Compared with healthy norms, children had significantly lower pre-LT PAQ scores (p = .002), pre- and post-6MWT scores (p < .001) and post-LT BOT-2 strength and agility scores (p < .001). Pre-LT, lower balance scores were associated with abdominal distention/ascites (p = .009) and splenomegaly (p = .017). Lower pre-LT platelet count correlated with poorer balance (r = .532, p = .017) and lower strength and agility scores (r = .446, p = .043). Significant moderate inverse correlations were found between weight/body mass index z-scores and BOT-2 components. Post-LT children continue to demonstrate decreased levels of motor proficiency and functional capacity but report less fatigue and increased physical activity.

CONCLUSIONS

Older children and adolescents undergoing LT are at risk of decreased physical function, highlighting the need for pre- and post-LT rehabilitation to optimize long term outcomes.

REPRODUCIBILITY OF PHYSIOLOGICAL VARIABLES OF THE SIX-MINUTE WALK TEST IN HEALTHY STUDENTS

OBJECTIVE

To verify the reproducibility of the six-minute walk test (6MWT) performance and its physiological variables in healthy students.

METHODS

This is as prospective cross-sectional study. The sample consisted of healthy students aged 6-12 years old from public and private schools in the region of Florianópolis City, Santa Catarina State, (Southern Brazil). The medical state was considered according to the health records and scores on the International Study of Asthma and Allergies in Childhood (ISAAC) and the spirometric values of forced expiratory volume in the first second and forced vital capacity above 80% of what was predicted. Two 6MWTs were conducted with a 30-minute interval between them, following the recommendations from the American Thoracic Society. Physiologic variables were recorded using the portable telemetric gas analyzer K4b2 (Cosmed®, Italy). For analysis, the dyspnea index, the perception of effort and performance variables identified in both 6MWT were considered. Data distribution was verified with the Shapiro-Wilk test and statistical analysis included paired t-test or Wilcoxon test, and intraclass correlation coefficient (ICC). The significance level adopted was 5%.

RESULTS

A total of 22 students with a mean age of 10.2±1.5 years participated in the study. The covered distance and the variation of oxygen consumption reproducibility between the two 6MWTs presented ICC=0.76 and ICC=0.86, respectively. There was also similar behavior of the physiological variables when comparing the two tests (p=0.001), especially the minute volume (MV), the oxygen consumption (VO2), and the carbon dioxide production (VCO2).

CONCLUSIONS

The 6MWT showed reproducible values, both in performance and physiological parameters, in the healthy students analyzed.