Relationship of AT measured as ml.min−1.kg−1to AT ml.min−1.m2. The metabolic cart is usually programmed to index as ml.min−1.kg-1 whereas the pulmonary artery catheter is programmed to index as ml.min-1.m2. Note that ml.min−1.m2 indirectly uses height in indexing. Indexing as ml.min−1.kg−1 does not use height. This graph allows direct comparison. Data from author’s laboratory.