Studies on the energy expenditure following surgical stress--(I. The effects of the severity of stress and the administration of nutrients).

Energy expenditure was studied in male Donryu rats, following two types of surgical stress, namely, laparotomy and burns. The rats with burns were subsequently fasted for 6 hours, by which time the resting metabolic expenditure (RME) became significantly decreased (84.3 +/- 9.5 per cent), as when compared to the pre-burn value (100 per cent), then increased 24 hours after the burn (132.9 +/- 10.1 per cent). The RME in burned rats receiving an intravenous infusion of electrolyte fluid, slightly increased 6 hours after the burn (109.0 +/- 15.8 per cent) and was almost identical to the RME in rats fed ad libitum for 24 hours after the burn. Rats with burns, that were given intravenous infusions of electrolytes and nutrients (TPN) already had a high RME value (134.6 +/- 7.0 per cent) 6 hours after the burn. In laparotomized rats fed ad libitum, no obvious changes in energy expenditure were observed 6 hours or 24 hours after the laparotomy, however, rats receiving TPN showed a moderately increased RME 6 hours after the laparotomy (113.9 +/- 3.4 per cent, p less than 0.05) which returned to the pre-stress level 24 hours post-operatively. These results confirmed that a phase of decreased RME (ebb phase), followed by a phase of increased RME were clearly observed after severe surgical stress, which indicated that appropriate treatments could shorten or extinguish the ebb phase.