Day 1 of recruitment A blood sample (up to 20ml) and urine sample (up to 20ml) will be collected from an indwelling arterial/venous catheter and indwelling foley catheter respectively at the initiation of the study. The blood sample will be centrifuged in order to isolate the serum. The serum will either (1) be frozen at -80˚C if there is no laboratory technician able to run the ELISA assay for resistin or (2) processed per manufacturer's instructions to measure serum resistin levels via ELISA assay.