Hyperkalaemia in bleeding trauma patients: A potential marker of disease severity - A retrospective cohort study

Abstract

Background: Hyperkalaemia is a common electrolyte abnormality seen in critically ill patients. In haemorrhagic shock, it may contribute to cardiac arrest and has been identified as a potential marker for tissue hypoxia. However, the significance of its role in haemorrhagic shock and its contribution to mortality remains unclear. This study aimed to examine the potential underlying pathophysiology and evaluate the incidence and characteristics of patients with hyperkalaemia on hospital arrival in bleeding trauma patients before transfusions and its mortality.

Methods: A retrospective cohort study was conducted on adult patients with traumatic bleeding admitted to a European Major Trauma Centre between January 2016 and December 2021. Patients were classified according to their serum potassium levels on arrival, and relevant clinical parameters between non-hyperkalaemic and hyperkalaemic patients were compared.

Results: Among the 83 patients in this study, 8 (9.6 %) presented with hyperkalaemia on arrival. The median shock index showed a higher tendency in the hyperkalaemic group. Hyperkalaemia was found to be more common among younger patients who sustained penetrating trauma. Mortality rates were higher in the hyperkalaemic group, but the difference was not statistically significant.

Conclusion: Our results suggest that hyperkalaemia occurs frequently in bleeding trauma patients on hospital arrival pre-transfusions, indicating a more severe illness. Our findings provide insights into the pathophysiology and characteristics of hyperkalaemia in bleeding trauma patients. Further studies are required to investigate the mechanisms by which hyperkalaemia contributes to mortality in haemorrhagic shock patients.

Keywords: Haemorrhage; Ischemia; Multiple trauma; Potassium; Shock.

Fig. 1

Pathophysiologic factors contributing to hyperkalaemia in haemorrhagic shock before transfusions. 1) Cellular level: increasing extracellular and intracellular hydrogen ions (H+) concentrations lead to extracellular hyperkalaemia through various cellular mechanisms. 2) Adrenergic vasoconstriction leads to end-organ damage, and renal underperfusion can significantly lead to lower potassium clearance. 3) Underperfused tissues due to insufficient perfusion lead to hypoxia-induced cell necrosis, increasing extracellular potassium concentrations—graph by Ariane Pessentheiner, licensed under CC BY-NC.

Fig. 2

Flowchart of patients included and analysed.

Fig. 3

Scatter plot with a linear regression line of potassium (mmol/L) and Lactate (mmol/L) showing a weakly positive correlation between these variables (ρ = 0.27).

Fig. 4

Raincloud plot shows the relationship between potassium (mmol/L) and Shock Index (SI). No significant difference between patients with high SI (≥1) and normal SI (<1) can be detected (p = 0.26).

Fig. 5

Kaplan-Meier curve for 24 h mortality, categorised into normo-, hyper- and hypokalaemia. Every point on x denotes 1 h.

Fig. 6

Kaplan-Meier curve for 30d mortality, categorised into normo-, hyper- and hypokalaemia. Every point on x denotes one day.