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Volume 3 Supplement 1

ESICM LIVES 2015

  • Poster presentation
  • Open Access

Chloride administration in the intensive care unit, an independent predictor of mortality

  • 1,
  • 2 and
  • 2
Intensive Care Medicine Experimental20153 (Suppl 1) :A975

https://doi.org/10.1186/2197-425X-3-S1-A975

  • Published:

Keywords

  • Independent Predictor
  • Hospital Mortality
  • Metabolic Acidosis
  • Chronic Health Evaluation
  • Retrospective Observational Study

Introduction

Chloride is the body's most important extracellular anion, important in many physiologic processes including acid base balance and osmotic pressure [1]. Hyperchloremic metabolic acidosis is a common finding in critically ill patients and may be associated with renal failure and even increased mortality [2].

Objectives

The objective of our study was to determine if chloride administration in a critically ill population is associated with hospital mortality.

Methods

We performed a retrospective observational study in a 24 bed tertiary mixed medical surgical ICU in a teaching hospital in the Netherlands. Patients admitted to the ICU in the period between January 1th 2008 and November 1th 2014 were screened for eligibility. Inclusion criteria were: 1. ≥ 18 years. 2. Length of stay (LOS) of ≥ 72 hours. Readmissions to the ICU were excluded. The primary end points for our analysis was hospital mortality. Univariate analysis was performed with Wilcoxon rank sum test for nonparametric data. Multivariate analysis was performed with predictors of ICU and hospital mortality (age, Acute Physiology and Chronic Health Evaluation IV predicted mortality) as well as factors associated with (hyper)chloremia, metabolic acidosis and fluid resuscitation. Chloride administration was defined as the total amount of chloride in mmol/l administered to a patient in a given time period.

Results

We studied 1471 patients. Mean age at admission was 67 years, APACHE II score 24, the average stay 10,5 days (table 1, baseline characteristics). In univariate analysis chloride levels at 72 hours were predictors of hospital mortality as were pH, chloride administration and total fluid administration (table 2). A multivariate analysis was performed to determine whether chloride, chloride administration, fluid administration and pH are independent predictors of mortality. This models shows that chloride levels are not an independent predictor of hospital mortality, chloride administration however is an independent predictor (OR 1.005; 95% CI 1.003-1.007 at 72 hours) as is pH, total fluid administration and age (table 3).
Table 1

Baseline characteristics.

 

Whole population Mean

Hospital survivors Mean

Non survivors Mean

Age (years)

67 ± 12

67 ± 13

69 ± 12

Sex (male)

64,9%

65,7%

62,6%

APACHE II Score

24 ± 7

22 ± 7

28 ± 7

Admission type medical

59%

53,1%

74,3%

Admission type surgical

41%

46,9%

25.7%

Length of stay at ICU (hours)

254

224

329

Acute renal failure

22.9%

20,4%

29,3%

CPR before admission

12.3%

9,9%

18,6%

Renal replacement therapy during ICU stay

30.6%

25,9%

42,8%

Table 2

Univariate analysis

 

Hospital survivors Mean

Non-survivors Mean

P

Chloride at admission (mmol/l)

106,6 ± 6,3

106,8 ± 6,5

0,986

Chloride at 72 hours (mmol/l)

106,3 ± 5,1

107,6 ± 5,1

0,000

pH at admission

7,33 ± 0,09

7,30 ± 0,10

0.000

pH at 72 hours

7,44 ± 0,06

7,41 ± 0,07

0.000

Total fluid administered at 24 hours (liters)

4,04 ± 2,6

4,41 ± 2,8

0.027

Total fluid administered at 72 hours (liters)

6,27 ± 3,5

7,58 ± 4,1

0.000

Chloride administered at 24 hours (mmol)

507 ± 306

566 ± 341

0.006

Chloride administered at 72 hours (mmol)

809 ± 425

809 ± 425

0.000

Table 3

Multivariate analysis

 

Hospital mortality

 

24 Hour

48 Hour

72 Hour

 

Odd ratio

Confidence interval

P value

Odd ratio

Confidence interval

P value

Odd ratio

Confidence interval

P value

Variable

         

APACHE 4 predicted mortality

14.352

8.84-23.31

0.000

14.6

8.88-24.31

0.000

11.74

7.51-18.35

0.000

Age

1.023

1.010-1.035

0.000

1.022

1.009-1.035

0.001

1.026

1.014-0.782

0.000

Total fluid administration

0.635

0.443-0.908

0.013

0.654

0.486-0.881

0.005

0.613

0.480-0.782

0.000

Chloride loading

1.004

1.001-1.007

0.013

1.004

1.001-1.006

0.003

1.005

1.003-1.007

0.000

pH

0.072

0.009-0.579

0.013

0.018

0.002-0.167

0.000

0.006

0.001-0.047

0.000

Chloride

1.004

0.977-1.032

0.763

1.020

0.990-1.051

0.188

1.003

0.998-1.052

0.071

Conclusions

In conclusion, chloride administration in a critically ill population is an independent risk factor for mortality, even when corrected for total fluid administration, pH and chloride levels. Further studies the optimal resuscitation fluid with regard to chloride levels are needed.

Authors’ Affiliations

(1)
Onze Lieve Vrouwe Gasthuis, Pediatric Intensive Care Unit, Amsterdam, Netherlands
(2)
Onze Lieve Vrouwe Gasthuis, Intensive Care Unit, Amsterdam, Netherlands

References

  1. Powers F: The role of chloride in acid-base balance. J Intraven Nurs. 1999, 22: 286-91.PubMedGoogle Scholar
  2. Berend K, et al: Chloride: The queen of electrolytes?. European Journal of Internal Medicine. 2012, 23: 203-211. 10.1016/j.ejim.2011.11.013.PubMedView ArticleGoogle Scholar

Copyright

© Smolders et al.; 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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