A Novel, Low-Cost Mobile Metabolic Measurement (M3) System

Summary Abstract Indirect calorimetry is based on measurement of the exchange of respiratory gasesAll aerobic energy releasing reactions in the body use oxygenoxygen consumptionV Ois proportional to energy expenditureEEResearchgrade indirect calorimetry systems measure V Ocarbon dioxide productionV COand minute ventilationV Ebreath by breath and then average results over multiple breaths to obtain accurate measures of cardiorespiratory functionThe maximum attainable VOi eVO maxis the gold standard for assessing cardiorespiratory tnessIn cardiac rehabilitationCRwhich is our focus hereinpatients with coronary artery disease or chronic heart failure undergo supervised exercise training to improve heart healthMost CR is performed in outpatient settingswhere the lack of equipment and specially trained sta have precluded objective measurement of key valuessuch as peak oxygen uptakeV O peakwhich is maximum V Oattained by the patient in a particular exercise stress testwhich is not necessarily her his maximum attainable VOMeasurement of VO peak is desired for tracking CR progress and for prescribing exercise intensitiesDue to its nonavailability in most outpatient settingssuboptimalsemi quantitative substitute measurese gheart rate reserveBorg ratings of perceived exertionorminute walk testare often employedAdditionallywith measurement of VEthe e cacy of CR at improving measures of breathing e ciencye gthe ratios VE VCOand VE VOcan be computedwhich is especially important for patients with high initial valuesLike VO peakthese e ciency metrics are seldom available in CR practice due to equipment and personnel limitationsTo obtain such measurespatients have to be scheduled for a cardiopulmonary exercise testCPETwhich is expensive andbeyond an initial testgenerally not covered by insuranceThe proposed Mobile Metabolic MeasurementMsystem will overcome these limitations and can be used during CR exercise sessions to track patient progress on a frequent basisObjectively measured VO peak values can be usedalong with heart rateto optimize exercise prescriptions to enable maximum safe progressThe Msystem will o er a huge advance in quantitative CR patient monitoringThe Msystem is a novelcost e ectiveportable device for accurately and reliably measuring V OV COV EV E V COV E V Othe respiratory exchange ratioR V COV Oand EEe gMETS or kilocaloriesThe proposed Msystemandapos s \one buttonandquotturnkeycalibration free operation and order of magnitude lower price compared to existing cart or mobile indirect calorimetry systems will make it practical and a ordable for use by non experts in outpatienthospitallaboratoryeldeducationaland even home settingsIn addition to CRother areas that could bene t from the Msystem include assessing the resting metabolic rateRMRof acutely ill and critically ill hospital patients to guide enteral and parenteral nutritionmonitoring the ventilatory status of patients being weaned from mechanical ventilatorsand guiding weight loss by quantifying the impact of dietary and exercise regimensMetabolic measurement is presently infeasible in many such applications Project Narrative The proposed Msystem will address the current gap in the availability of an inexpensiveeasy to useand accurate system for measuring V O peakV E V COV E V Oand R in cardiac rehabilitationCRsettings for tracking patientsandaposphysiological responses to exercise and optimizing their exercise prescriptionsIt is well documented in the literature that the key limitations of the gold standard cardiopulmonary exercise testCPETare directly related to the expertise required to perform the test and its associated costsboth equipment and personnelEven outside of CR applicationsthe proposed Msystem represents a transformative technology that will not only compete in existing marketsbut will contribute to the creation of new marketse gteam sportshealth and wellness applicationsetcwhich will further drive down its cost