Evaluation of laboratory critical serum potassium values and their association with clinical symptoms in Chinese Han patients

Objectives A retrospective, observational study to evaluate the association between critical potassium values and clinical symptoms, and to define critical potassium limits in hospital inpatients of Chinese Han ethnicity. Methods Adult patients (aged 18 years) of Chinese Han ethnicity admitted to the Beilun People's Hospital of Ningbo, Zhejiang University, China, were sequentially enrolled. Inpatient data recorded on admission (or at first time during hospital stay for serum potassium values) between 1 January 2011 and 31 December 2012 were used to calculate the percentage of patients with relevant clinical symptoms, the percentage of critical patients (presence of neurological symptoms and deterioration of at least two physiological systems), and the hospital prevalence of clinical symptoms. Correlations between critical serum potassium values and clinical symptoms were determined. Results Out of 3 665 included patients, 1 514 patients with a critical serum potassium value (as determined in the present study) were mainly treated in the intensive care unit or the haematology department (low serum potassium, 2.9mmol/l), and Renal and Hepatitis departments (high serum potassium, 6.0mmol/l). High critical serum potassium values (6.0mmol/l) were significantly correlated with clinical symptoms (such as neurological symptoms, loss of appetite, oliguria and hypotension). Low critical serum potassium values (2.9mmol/l) were significantly correlated with clinical symptoms (such as neurological symptoms, loss of appetite and dyspnoea). Conclusions Based on the present findings, the lower and upper critical potassium limits were defined as 2.9mmol/l and 6.0mmol/l, respectively.