Changes in pH and electrolytes during therapeutic plasma exchange in patients with liver diseases and factors predictive of these changes.

Therapeutic plasma exchange (TPE) disturbs the pH and electrolyte status. This study aimed to analyze the changes in pH, ionized calcium (iCa), sodium (Na), potassium (K), and bicarbonate (HCO3 ) of patients undergoing TPE and factors affecting these changes. The study included patients (age > 16 years) undergoing TPE from July 2016 to August 2017. Data on patient demographics, TPE procedures, pre-, and immediate post-TPE blood gas analysis values and adverse events during TPE were collected. A statistical analysis of the data was done to determine changes in pH and electrolytes and the factors affecting them. The changes in iCa, Na, and K due to the procedure were found to be statistically significant (P < .001). The changes in systolic (P = .010) and diastolic (P = .001) blood pressure during the procedure were significant. The predictors for the change in iCa were pre-procedure iCa (P < .001), age of the patient (P < .001), and the pre-procedure pH (P = .002). Complications related to hypocalcemia occurred in 12% of the TPE procedures. Hypocalcemic manifestations did not show any significant association with pre-procedure iCa levels, change in iCa levels during the procedure and age or gender of the patient. TPE induces marked changes in electrolytes but these changes are transient and do not warrant any intervention. The correction of iCa levels pre-TPE and continuous infusion of calcium during the procedure helps prevent marked fluctuations in iCa levels. This does not eliminate risks of hypocalcemia. Vigilance and preparedness to deal with complications related to hypocalcemia is the best strategy.