Disorders of Water Balance Following Sellar and Suprasellar Surgeries: Patterns, Determinants and Utility of Quantitative Analysis

BACKGROUND AND OBJECTIVE: The primary objective of this study was to evaluate the application of principles of quantitative analysis to assess disorders of water balance following surgeries for sellar and suprasellar masses and also to investigate potential factors influencing the occurrence and course of these disorders. MATERIALS AND METHODS: A total of 36 consecutive adult patients who underwent surgery for sellar and suprasellar masses between 2014 and 2015 were prospectively followed up in this observational study. Twenty-one patients had complete laboratory parameter records for quantitative analysis. Clinical parameters, daily fluid balance, and sodium balance were calculated based on the fluid chart and the estimation of sodium concentration of fluids and urine. Classical Edelman equation was used to predict the sodium values. Time course of these disorders and association with etiological and other clinical parameters were assessed. Standard institutional protocol was used in the management of patients studied. RESULTS: Comparison between predicted values of quantitative analysis and observed values of sodium showed that 80-95% of the observed readings on various days showed concordance with calculated reading, with <5% error. 77.7% manifested at least one episode of dynatremia relating to water balance disorder during the postoperative period. Postoperative diabetes insipidus (DI) observed in 58% of patients, whereas syndrome of inappropriate antidiuretic hormone secretion observed in 47% of patients. Both DI and SIADH in different time points were noticed in 28%, and classical triple phase response was seen in 2.7%. Nearly 83% manifested one episode of dynatremia relating to water balance disorder during the post-operative period. Prolonged DI was noted in 11% and no case of cerebral salt wasting was observed in any of the patients studied. CONCLUSION: We observed high degree of correlation between the predicted and observed sodium values. Quantitative analysis in the management of patients with disorders of water balance in postsurgical settings in neurosurgery has the potential for improving clinical care.