Type A lactic acidosis in occupational heat exhaustion.
BACKGROUND
This paper presents a further analysis of biochemical data collected during a 1 year prospective study of 106 cases of heat exhaustion at a deep underground metalliferous mine.


RESULTS
Multiple regression analysis results indicate that the haemoglobin, serum creatinine and plasma lactate concentrations are statistically significant predictors of the anion gap. Together, they explain 65% of the variance in the anion gap (R(2) = 0.650). Spearman's rho correlation results also confirm that haemoglobin, creatinine and lactate are each statistically significantly correlated with the anion gap (P < 0.001).


CONCLUSIONS
These results indicate that dehydration and lactate are important determinants of the metabolic acidosis previously observed in occupational heat exhaustion. It is likely that dehydration in these workers has resulted in poor muscle perfusion, anaerobic conditions and elevated lactate. This constitutes Type A lactic acidosis. Creatine kinase is not a statistically significant predictor of the anion gap in multiple regression (P = 0.956). Furthermore, the Spearman's rho correlation coefficient for creatine kinase versus the anion gap is weak (r(s) = 0.175) and is not statistically significant (P = 0.073). These results suggest that there was no rhabdomyolysis contributing to the metabolic acidosis.
Donoghue
A M
AM
The School of Public Health, Queensland University of Technology, Victoria Park Road, Kelvin Grove, Brisbane, QLD 4059, Australia. amdonoghhue@bigpond.com
D000136:Acid-Base Equilibrium; D000140:Acidosis, Lactic / Q000097:blood / Q000150:complications*; D003402:Creatine Kinase / Q000097:blood; D003404:Creatinine / Q000097:blood; D006359:Heat Exhaustion / Q000150:complications*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007773:Lactates / Q000097:blood; D008669:Metallurgy; D008906:Mining; D009784:Occupational Diseases / Q000097:blood / Q000150:complications*; D011446:Prospective Studies; D012044:Regression Analysis
D006454:Hemoglobins; D007773:Lactates; D003404:Creatinine; D003402:Creatine Kinase