13 Original article SWISS MED WKLY 2006;136:13–18 · www.smw.ch Peer reviewed article Feasibility of mobile cardiopulmonary exercise testing Adrian Attinger a , Claudia Tüller a , Tjeu Souren b , Michael Tamm a , Christian Schindler c , Martin H. Brutsche a a Pneumology, University Hospital Basel, Basel, Switzerland b VIASYS Healthcare GmbH, Hoechberg, Germany c Institute for social and preventive medicine, University of Basel, Basel, Switzerland Questions under study: Evaluation of cardiopul- monary capacity and work ability is often done by cardiopulmonary exercise testing under laboratory conditions. Mobile CPET devices allow measure- ments under specific real-life conditions, ie at the patient’s workplace. We investigated the feasibility and validity of mobile CPET in healthy controls. Method: We compared oxygen uptake mea- sured by mobile CPET (MCPET) with that by standard CPET (LCPET), and we compared oxy- gen uptake with markers of self-reported physical exhaustion. Twenty-two healthy subjects (15 male, 21–49 years) underwent LCPET and 6 outdoors 12-min running tests (MCPETs) at different in- tensities. Physical exhaustion and the time they could continue exercising (T EX ) was reported for each level. Standard descriptive statistics were ap- plied. Results: Of 132 MCPETs, performed in 22 sub- jects, 128 (97%) were of suitable quality. The face- mask was well tolerated and nobody felt uncom- fortable at any time. On average VO 2 [peak] was 21% (SD 9%) higher with MCPET compared to LCPET (median 3.60, range [2.22, 5.14] versus median 2.63, range [1.67, 4.16] L*min –1 ), but showed a strong correlation (r 2 = 0.90). MCPET- VO 2 at steady state correlated with subjectively rated physical exhaustion, and with TEX. Conclusions: Out-of-laboratory MCPET was feasible, correlated with parameters of standard CPET, and correlated with markers of physical exhaustion. After validation in patients, MCPET could be used for a rational evaluation of cardio- pulmonary capacity and work ability in selected patients. Key words: cardiopulmonary exercise test; impair- ment; work ability; endurance; telemetry Summary Introduction For the evaluation of cardiopulmonary capac- ity, work ability and prognosis of patients with proven or suspected cardiac or pulmonary diseases, resting measurements such as pulmonary function or echocardiography are not in all cases conclusive [1–4]. Often, a maximal cardiopulmonary exercise test (CPET) is done during diagnostic work-up, and different studies document its diagnostic value and impact on clinical decision-making [3, 5, 6]. Especially in patients whose work-related com- plaints are disproportionate to the resting lung function CPET is helpful. However, CPET is usu- ally performed under laboratory conditions (in- doors, air conditioning) with either a treadmill or a cycle ergometer. This differs from real-life con- ditions experienced at work (temperature, humid- ity, dust), and the continuous type of exercise (cycling, walking) might not reflect physical activ- ity during work (on-and-off exercises, intervals of high exercise-load).Therefore, to draw direct con- clusions from CPET to work ability might not be adequate in some patients. Recently, different tele- metric mobile devices for cardiopulmonary exer- cise testing have become available. They allow per- Abbreviations CPET Cardiopulmonary exercise test MCPET Mobile cardiopulmonary exercise test LCPET Laboratory-based cardiopulmonary exercise test Er Subjectively rated respiratory exhaustion on a visual analogue scale Em Subjectively rated muscular exhaustion on a visual analogue scale Eo Subjectively rated overall exhaustion on a visual analogue scale Tex Subjectively estimated time to exhaustion for a given exercise intensity VO2 Oxygen uptake (L/min) FEV1 Forced expiratory volume in the first second ATS American Thoracic Society VAS Visual analogue scale