Physiological Responses to Maximal Exercise Testing and the Modified Incremental Shuttle Walk Test in Adults After Thermal Injury

Kellie Anne Stockton, Mark John Davis, Michael Graeme Brown, Robert Boots, Jennifer Davida Paratz

The ongoing hypermetabolic response associated with burn injury contributes significantly to loss of function, morbidity, and mortality. Exercise is strongly recommended to assist recovery and overall functional outcome. To date, there have been limited studies investigating the validity and practicality of both maximal laboratory and field tests in adult burns survivors. The objective of this study was to determine the metabolic and ventilatory response to cardiopulmonary maximal exercise testing (CPET) and the modified shuttle walk test (MSWT) in adult burns patients. Fifteen people (13 male) with a mean TBSA of 38.5% (16.0%) underwent both MSWT and CPET within a 5-day period in random order. The majority of participants demonstrated a normal response to CPET. Two participants with a history of inhalation burns demonstrated a respiratory limitation to exercise with desaturation (91 and 89%) at the end of the CPET, which returned to normal within 2 minutes after exercise. The correlation between VO(2peak) as measured via CPET and distance as measured in MSWT was 0.7. Mean results measured in MSWT for maximal heart rate and perceived exertion scores were lower than those achieved with CPET results: 91 and 88%, respectively. There were no adverse events during both the MSWT and CPET. This study demonstrates that after burn injury, CPET and MSWT can be performed safely in the majority of patients early in the postdischarge rehabilitation period. MSWT is likely to be submaximal at 80 to 90% of CPET results but is easy to replicate and cost-effective, thus a viable mechanism for monitoring aerobic capacity.