Changes in selected electrolytes in adult intensive care patients at the University Teaching Hospital, Lusaka, Zambia

Background: The importance of regulating electrolyte levels is well recognized in most Intensive Care Units (ICU). Various institutions across the globe have found varying figures on the extent and causes of electrolytes derangements in ICUs. The extent of electrolyte and fluid imbalance in patients being admitted and already admitted to the Main ICU (MICU) at the University Teaching Hospital (UTH) Lusaka Zambia is unknown. This study aimed to explore the 24hour changes in sodium and potassium in adult MICU patients at the UTH, Lusaka, Zambia. Methods: This was a prospective cohort study of the patients admitted to the MICU at UTH, Lusaka, Zambia. Data was collected over a four-month period (August to November) in 2017. Only consenting patients 18 years and above admitted for at least 24 hours in the unit were enrolled. On admission, routine baseline investigations were obtained from every patient which included a full blood count and renal function tests. The second set of investigations was collected 24 hours post MICU admission. The blood samples were obtained from a peripheral vein in heparinized bottles for renal function tests. Serum electrolyte analysis was done was at UTH. Normal serum concentrations of sodium and potassium were considered as 135-145mmol/l and 3.5 - 4.5mmol/L, respectively. Comparisons between means were done with the Wilcoxon signed-rank test. Logistic regression analysis was used to investigate the relationship between dependent and independent variables. A p-value < 0.05 was considered statistically significant. Statistical analysis was performed with STATA 13 SE. Results: A total number of 100 patients were included in this study with a mean age of 36.8 years (SD = 12.1). The mean value of sodium level was 136.7 (SD = 8.9) mmol/L and 139.0 (SD = 11.6) mmol/L, on admission and 24 hours post-admission respectively. This difference in serum sodium level was shown to be statistically significant with a P-value = 0.0051. Hypernatremia was shown to be associated with an increased risk of death (p = 0.021) in the Unit with an odds ratio of 4.0 at 95% confidence interval of 1.3 to 13.8. Hyponatremia was the most prevalent electrolyte imbalance but was neither shown to be associated with mortality (P-value = 0.18) nor prolonged ICU stay (0.56) at 24 hours post-admission. The mean value of potassium level was 4.2 (SD = 1.1) mmol/L and 4.3 (SD = 1.1), on admission and 24 hours post-admission respectively. This difference was not statistically significant (P-value = 0.57). Conclusion: There was a statistically significant change in serum sodium levels after 24 hours post-admission but there was no statistically significant change in potassium. Hyponatremia was the most prevalent abnormality whilst hypernatremia had a statistically significant association with mortality. Therefore, electrolyte imbalances can occur as early as the first day of admission in ICU with fatal complications. Correcting electrolyte imbalances in MICU patients is an urgent necessity and should not be delayed.