High serum lactic acid concentration after laparotomy and peritonitis in iron stores depletion. An experimental study on the rat.

Total depletion of iron stores with a moderately decreased blood hemoglobin concentration (114 x 10 vs. 155 x 12 g/l in controls, n = 28) was produced in rats (n = 28) by rearing them for six weeks on an iron free diet, in iron free cages, starting at two weeks of age. The controls were treated at the same time in same conditions, except that they were given a normal supply of dietary iron. In all rats laparotomy and peritonitis by ligation and puncture of the caecum were carried out with ether anesthesia. Postoperative mortality and blood lactic acid concentration were followed for 120 minutes after the procedure. Postoperative mortality (8 of 28, 29% vs. 1 of 28, 4%) and blood lactic acid concentration (3.3 x 0.3 to 3.6 x 0.5 vs. 1.4 x 0.1 to 1.8 x 0.2 mmol/l) were higher (p less than 0.001) in the experimental group than in the control animals. The surviving rats (2.0 x 0.1 to 2.1 x 0.2 mmol/l) had a lower (p less than 0.001) blood lactic acid concentration than those who died (5.6 x 0.5 to 6.1 x 1.1). The results suggest that total lack of iron producing a moderate decrease of blood hemoglobin concentration creates a significant risk in abdominal surgery and focus the activation of the anaerobic energy yielding process.