Encephalopathy, oxygen consumption, visceral amino acid clearance, and mortality in cirrhotic surgical patients

To assess the relationship of the high mortality of coma in cirrhotic surgical patients to defects in energy metabolism, reduced utilization of amino acids by the liver and other visceral tissues, oxygen consumption, central plasma clearance rate of amino acids (CPCR of amino acids), and the plasma concentrations of plasma inducing factors were measured in a series of 59 cirrhotic patients. They were classed as alert, encephalopathic, and comatose (Groups A, E, and C, respectively). The comatose group was set apart from the other two by a significantly higher mortality of 83 percent (p < 0.005) combined with a lower whole body oxygen consumption of 103 ± 6.8 ml/min per m 2 compared with 135 ± 10 ml/min per m 2 in alert patients and 159 ± 12 ml/min per m 2 in the encephalopathic patients (p < 0.01) and CPCR of amino acids of only 120 ± 20 ml of plasma/min per m 2 compared with 240 ± 30 ml of plasma/min per m 2 in the alert patients and 300 ± 50 in the encephalopathic patients (p < 0.01). An inverse correlation of tyrosine and phenylalanine concentrations existed with both whole body oxygen consumption (r = −0.56, p < 0.01) and also with total amino acid clearance (r = −0.61, p < 0.01). Tyrosine and phenylalanine concentrations also correlated directly with the octopamine concentration (r = 0.64, p < 0.01). Thus, we conclude that coma is a symptom of hyperaminoacidemia, but that death is the result of impaired oxidative energy production and a deficiency of amino acid clearance for synthesis of proteins required for survival.