Metabolic Intervention in Surgical Patients

Abstract

We have assessed the effect of a variety of forms of metabolic intervention on both energy and protein metabolism in 44 severely ill surgical patients. The patients were studied either in the basal state or while receiving total parental nutrition (TPN), and the metabolic effects were assessed using the primed-constant infusion of a combination of stable isotopes and radioisotopes. Somatostatin infusion, either in the basal state or in the TPN, did not change glucose kinetics, but there was a significant decrease in the rate of net protein catabolism (NPC). In the basal studies the rate of NPC decreased from 3.4 .+-. 0.7 g/kg/d to 2.9 .+-. 0.7 g/kg/d (p < 0.002), while in the TPN patients the corresponding values were 1.48 .+-. 0.61 g/kg/d and 1.10 .+-. 0.50 g/kg/d, respectively (p < 0.005). Histamine type 2 blockade with ranitidine did not significantly alter glucose kinetics, but in both the TPN patients and in the basal state ranitidine was associated with a significant decrease in the rate of NPC. In the basal state rate of NPC was 2.44 .+-. 0.53 g/kg/d and during ranitidine infusion the value was 2.08 .+-. 0.42 g/kg/d (p < 0.04). Naloxone infusion did not alter glucose kinetics, but there was a significant decrease in the rate of NPC from a basal value of 2.6 .+-. 0.6 g/kg/d to 2.3 .+-. 0.5 g/kg/d (p < 0.04). The infusion of the prostaglandin antagonists diclofenac or dypyridamole resulted in increases in the plasma insulin level, and as a result glucose turnover decreased in both groups. In the diclofenac group the rate of glucose turnover decreased from 14.4 .+-. 1.7 .mu.mol/kg/min to 12.6 .+-. 1.3 .mu.mol/kg/min (p < 0.02). Neither prostaglandin antagonist resulted in any significant change in the rate of NPC. Beta-adrenergic stimulation with salbutamol resulted in a significant increase in glucose turnover from 12.1 .+-. 1.1 .mu.mol/kg/min to 13.4 .+-. 0.9 .mu.mol/kg/min (p < 0.02), and the rates of appearance (Ra) of both alanine and free fatty acids (FFAs) also increased. Alanine Ra increased from 11.7 .+-. 2.5 .mu.mol/kg/min to 12.8 .+-. 3.0 .mu.mol/kg/min, and the corresponding values for FFA turnover were 7.6 .+-. 1.1 .mu.mol/kg/min and 10.3 .+-. 2.1 .mu.mol/kg/min (p < 0.03), respectively. Salbutamol infusion did not result in any significant change in the rate of NPC. We conclude from these studies the following 1) The infusion of somatostatin, ranitidine, or naloxone results in a significant decrease in the rate of NPC in severely ill surgical patients both in the basal state and during TPN. (2) The aforementioned three agents do not influence glucose kinetics in any major way. (3) The infusion of prostaglandin antagonists does not result in any significant decrease in the rate of NPC, but insulin and cortisol levels change and glucose production decreases. (4) The infusion of the beta-agonist salbutamol results in the mobilization of both glucose and FFA, but there is no associated conservation of protein.