Risk of respiratory failure among hospitalized patients with various admission serum potassium levels

ABSTRACT

Background

The objective of this study was to assess the relationship between admission serum potassium and the risk of respiratory failure requiring mechanical ventilation in all hospitalized patients.

Methods

All non-dialysis and non-mechanically ventilated patients who had serum potassium measurement at admission from 2011 to 2013 were studied. Serum potassium levels were stratified into five groups; ≤3.4, 3.5 to 3.9, 4.0 to 4.4, 4.5 to 4.9, 5.0 to 5.4, and ≥5.5 mEq/L. The outcome of interest was the respiratory failure requiring mechanical ventilation during hospitalization. Logistic regression analysis was performed to assess the independent risk of in-hospital respiratory failure requiring mechanical ventilation based on various admission serum potassium, using serum potassium of 4.0 to 4.4 mEq/L as the reference group.

Results

Of 67,034 eligible patients, with the mean admission serum potassium of 4.2 ± 0.5 mEq/L, 2,886 (4.3%) patients developed respiratory failure requiring mechanical ventilation during hospitalization. As demonstrated by U-shaped association, increased risk of in-hospital respiratory failure was significantly associated with low admission serum potassium ≤ 3.4 mEq/L (odds ratio 1.36, p-value <0.001) and high admission serum potassium ≥5.5 mEq/L (odds ratio 1.37, p-value = 0.01).

Conclusion

Increased risk of in-hospital respiratory failure requiring mechanical ventilation was noted when serum potassium was below 3.5 mEq/L or above 5.4 mEq/L at the time of hospital admission. Patients with either hypokalemia or hyperkalemia are at risk of respiratory failure requiring mechanical ventilation.

KEYWORDS:

• Potassium
• hypokalemia
• hyperkalemia
• respiratory failure
• electrolytes

Authors’ contributions

All authors had access to the data and a role in writing the manuscript.

Declaration of funding

The contents of the paper and the opinions expressed within are those of the authors, and it was the decision of the authors to submit the manuscript for publication.

Declaration of interest

All authors declare no conflict of interest.

Declaration of financial/other relationships

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.