SAT619 Post-operative Fluid Restriction Prevents Hyponatremia And Readmissions After Pituitary Surgery

Disclosure: J.J. Chang: None. D. Veruttipong: None. O. Chu: None. W. Erin: None. V. Gates-Bazarbay: None. S. Kling: None. K. Vinluan: None. S. Chittum: None. M. Alhadha: None. J. Fernandez-Miranda: None. Background: Delayed hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion is the most common cause of readmission after pituitary transsphenoidal surgery (TSS). Post-operative fluid restriction (FR) after discharge may effectively reduce hyponatremia and related readmissions. Methods: Our aim was to assess the effectiveness of FR after TTS. We compared post-operative day (POD) 8 hyponatremia and related readmission rates pre- and post- FR protocol implementation at our institution. Pre-FR (July 1, 2018-March 15, 2020) post-TSS patients were instructed to drink ad lib or to thirst on discharge. Post-FR (March 16, 2020-December 31, 2020), post-TSS patients were routinely provided education and documentation on the outpatient protocol that recommended 1 liter/day FR from POD 3-5 to POD 8-10. Serum sodium was assessed at POD-8 for all patients. Patients hospitalized for more than 5 days after surgery, had untreated adrenal insufficiency, or had pre-existing AVP deficiency were excluded. Results: The average POD-8 sodium level was lower in the 115 patients in the pre-FR cohort than the 216 patients in the post-FR cohort (135.8±6.7 vs. 138.1±4.4 mEq/L; Wilcoxon-Mann-Whitney test p=0.0081). POD-8 hyponatremia (Na ≤134 mEq/L) occurred in a lower proportion of patients post-FR (15.0%; 32/214) than pre-FR (28.9%; 30/104) (Chi-Square test p=0.0033). Similarly, severe hyponatremia (Na ≤124 mEq/L) occurred in a lower proportion of patients post-FR (1.4%; 3/214) than pre-FR (8.7%; 9/104) (Fisher test p= 0.01). Only 1.4% (3/216) of patients were readmitted post-FR compared to the 8.7% (10/115) pre-FR (Fisher test p=0.0020). Conclusions: Our retrospective evaluation showed that implementation of post-TSS FR protocol significantly decreased hyponatremia by nearly 50% and readmissions by over 80% compared to the prior standard of care of drink ad lib or to thirst. FR should be considered standard-of-care for eligible patients without ongoing AVP deficiency to reduce hyponatremia and readmission burden to both patient and healthcare system. Presentation: Saturday, June 17, 2023