The Scientific World Journal

Volume 2012 (2012), Article ID 234628, 1 page

doi:10.1100/2012/234628

Letter to the Editor

Hypochloraemia and Worse Clinical Outcome in Critically Ill Patients

Rainer Gatz¹ and Paul Elbers²

¹ICU, Herlev Hospital, 2730 Herlev, Denmark

²ICU, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands

Received 1 August 2012; Accepted 30 August 2012

Copyright © 2012 Rainer Gatz and Paul Elbers. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Tani et al. recently found an association between hypochloraemia and worse clinical outcome in critically ill patients, albeit not as an independent risk factor [1].

The authors were unable to find any explanation for this association. From clinical experience we could invoke three possible causes: use of NaHCO₃, use of loop diuretics, or renal compensation for acidosis, all of which might be more prevalent in sicker patients. One of the tables presents data about the “strong ion gap” (SIG) in the three subgroups of hyper-, normo-, and hypochloraemic patients, with mean values of, respectively, 3.5 versus 4.8 versus 6.2 mEq/L. The corresponding -value is <0.0001. The authors do not mention this in their discussion section, though. While the value of SIG as an independent risk factor for poorer clinical outcome may not be proven, there are a few studies that indicate such a relation [2–6]. The link between hypochloraemia and worse clinical outcome might thus be that hypochloraemia is an indicator of higher SIG values. It would be highly interesting if the authors could contribute to this aspect of their data.

References

M. Tani, H. Morimatsu, F. Takatsu, and K. Morita, “The incidence and prognostic value of hypochloremia in critically ill patients,” The Scientific World Journal, vol. 2012, Article ID 474185, 7 pages, 2012.

A. T. Maciel and M. Park, “Differences in acid-base behavior between intensive care unit survivors and nonsurvivors using both a physicochemical and a standard base excess approach: a prospective, observational study,” Journal of Critical Care, vol. 24, no. 4, pp. 477–483, 2009.

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L. J. Kaplan and J. A. Kellum, “Initial pH, base deficit, lactate, anion gap, strong ion difference, and strong ion gap predict outcome from major vascular injury,” Critical Care Medicine, vol. 32, no. 5, pp. 1120–1124, 2004.

G. C. Funk, D. Doberer, F. Sterz et al., “The strong ion gap and outcome after cardiac arrest in patients treated with therapeutic hypothermia: a retrospective study,” Intensive Care Medicine, vol. 35, no. 2, pp. 232–239, 2009.