[Hypernatremic alkalosis. Possible counterpart of hyperchloremic acidosis in intensive care patients?].

BACKGROUND

With broad acceptance of Stewart's acid-base model "hyperchloremic acidosis" is regarded as an independent form of metabolic disorder. It is unknown whether hypernatremia plays a corresponding role with respect to the development of alkalosis.

METHODS

A total of 201 artificially ventilated, critically ill patients were monitored for hypernatremic episodes. Inclusion criterion was a serum sodium concentration above 145 mmol/l.

RESULTS

In 20 patients a total of 78 periods of elevated plasma sodium levels lasting at least 24 h were observed. In 86% of these cases sodium and chloride concentrations were simultaneously increased. The development of alkalosis correlated with the strong ion difference (r=0.80, p<0.01) but not with the serum sodium concentration (r=-0.031, p=0.78). In cases without accompanying hyperchloremia (13%) metabolic alkalosis regularly occurred and a correlation between serum sodium concentration and base excess could be verified (r=0.66, p=0.03). Alkalosis occurred in 84.8% of cases where the strong on difference exceeded 39 mmol/l.

CONCLUSION

From the available data hypernatremic alkalosis could not be defined as an independent metabolic disorder. In would seem more appropriate to use the term "strong ion alkalosis" in this context.