Comparison of measures of physiologic stress during treadmill exercise in a patient with 20% lower extremity burn injuries and healthy matched and nonmatched individuals

Patients with burn injuries are referred for rehabilitation within days aft er the injuries to encourage early ambulation and functional training. Many of these patients are hypermetabolic at rest. Metabolic demands of activit y are added to the already hypermetabolic state and elevate total energy re quirements and some physiologic measures. Reports on the physiologic stress imposed by therapeutic activities for patients with burn injuries are limi ted to low levels of metabolic demand (less than or equal to 2 metabolic eq uivalents [METS]). The degree of stress imposed by functional activities su ch as ambulation (3 METS) and stair climbing (5 METS) is not known for adul ts with burn injuries. The purpose of this study was to report the clinical measures of myocardial and physiologic stress in a patient with 20% lower extremity total body surface area bunts during an exercise challenge equiva lent to stair climbing. Physiologic measures were assessed before and durin g a treadmill activity (5 METS) for a 40-year-old obese man 3 weeks after h e had lower extremity burn injuries. These measures were compared with mean values for 62 healthy counterparts and 6 healthy subjects matched for age, gender, and fitness level. Heart rate, systolic blood pressure, rate press ure product, and the rating of perceived exertion for the patient with burn injuries were higher at baseline and during exercise than the mean values for the 62 healthy individuals and the 6 matched subjects. The steady state exercise values for heart rate, systolic blood pressure, rate pressure pro duct, and rating of perceived exertion at 6 minutes were 189 beats per minu te, 190 mm Hg, 3591, and 17, respectively, for the patient with burn injuri es and were 111.3 beats per minute, 149 mm Hg, 1680, and 11.7, respectively , for the 6 matched subjects. Ventilation during exercise also increased fo r the patient with burn injuries more than for the matched subjects (3/4 vs 1/4). Pain experienced by the patient with burn injuries decreased with ac tivity (9.8 vs 7.3 on a 15cm scale). Treadmill walking produced near maxima l responses for most physiologic measures for this patient who was hypermet abolic at rest. We provided normative data to assist therapists who work wi th patients with similar burn injuries.