A comparison of oxygen uptake and venous blood lactic acid values for normal subjects and cardiac patients while performing a modified Bruce protocol

• Main Author: Sullivan, Michael J.
• Other Authors: Getchell, Leroy H.
• Format: Others
• Published: 2011
• Subjects: Heart function tests.; Heart > Diseases > Patients > Rehabilitation.
• Online Access: http://cardinalscholar.bsu.edu/handle/handle/182614; http://liblink.bsu.edu/uhtbin/catkey/386086

Clinically, the modified Bruce protocol is widely used to predict functional capacity in cardiac patients. However, it has been suggested that cardiac patients have lower oxygen uptakes for standard workloads. In order to study this, we measured oxygen uptake (V02) and venous bloodV02 derived from lactic acid concentration during a modified Bruce treadmill protocol in 12 pest myocardial infarction (MI) and 12 normal males. During three stages of the protocol mean oxygen uptake was significantly lower (1.42 - 6.2 ml/kg.min; p < .001) for the pest MI than the normal males.However, venous blood lactic acid concentrations were not different at these stages. The MI patients' measured V02 for three stages of the protocol ranged from 1.8 - 7.3 ml/kg.min lower than the Bruce predictions for cardiacs. In addition, measured V02 (max) for cardiac patients were from 3.68 to 11.15 ml/kg.min lower than the predicted the normal subjects. These data suggest myocardial damage may slow oxygen kinetics and results in lower actual V02during treadmill testing. However, blood lactic acid concentrations failed to demonstrate an anaerobic compensation for the lower V02 in pest MI patients.