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Hyperosmolar coma due to exclusive glucose accumulation: Recognition and computations
Author(s) -
BARTOLI ETTORE,
SAINAGHI PIER PAOLO,
BERGAMASCO LUCA,
CASTELLO LUIGI
Publication year - 2009
Publication title -
nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 61
eISSN - 1440-1797
pISSN - 1320-5358
DOI - 10.1111/j.1440-1797.2008.01054.x
Subject(s) - concomitant , extracellular fluid , medicine , coma (optics) , plasma glucose , computation , extracellular , endocrinology , algorithm , physics , chemistry , mathematics , biochemistry , insulin , optics
SUMMARY Aim: To avoid electrolyte derangements during correction of hyperosmolar coma (HC), PNa PREDICTED at the end of correction is presently estimated from plasma glucose (P G , mM/L). When the rise in plasma osmolality (Posm) is entirely due to glucose addition (G A , mM) to the extracellular volume (ECV), this PNa prediction can be improved by correctly estimating G A and any associated water loss (ΔV), while excluding any concomitant Na loss (ΔNa). Methods: Indicating with 0 the normal conditions, with 1 the HC, establishes an exclusive G A accumulation. We derived the equations for computing G A , ΔV and PNa PREDICTED . Computer simulations of HC were performed by adding the known G A while subtracting the known ΔV and ΔNa in different combinations, obtaining exact values of PNa 1 and . Applying our formulas, we recognized and discarded all cases with concomitant ΔNa, and we computed G A , ΔV and PNa PREDICTED from PNa 1 and , as if they had been measured in patients. We extended these same calculation algorithms to 68 patients with HC. Results: In computer simulations, true and calculated G A , ΔV and PNa PREDICTED were identical, such that regression and correlation coefficients were 1 ( P < 0.0001). Out of the 68 patients recruited, 13 fulfilled the boundary conditions of an exclusive G A addition. The true values, obtained by balance studies performed on these patients, were not different from and significantly correlated with the calculated data ( R 2 = 0.99, P < 0.001). Conclusion: Our new model system for HC and the new formulas improve to near exactness the accuracy in estimating PNa PREDICTED , helping the physician to avoid unwanted electrolyte derangements during treatment.