Post-Operative Water Load Following Transsphenoidal Pituitary Surgery

Delayed post-operative hyponatremia occurs in 5-20% of patients following pituitary surgery and typically occurs on post-operative day 5-10.This decline in sodium can occur rapidly and have serious consequences such as altered mental status, seizures, coma, and even death. Despite significant research into patient demographics and risk factors, the investigators have not been able to predict which patients will suffer from delayed post-operative hyponatremia to date. At the Barrow Neurological Institute, physicians currently utilize an outpatient screening protocol to monitor patients' sodium levels after surgery, but this has yet to be effective for reducing readmissions following pituitary surgery. The etiology of delayed post-operative hyponatremia has been linked to water and sodium dysregulation in the post-operative period. It has been shown that post-operative day 1-2 sodium levels are statistically lower in patients who develop delayed hyponatremia, however, the numerical differences are not large enough to guide clinical management. The investigators propose that a water load on post-operative day 1 may expose underlying sodium/water dysregulation in the early post-operative period. This would improve physicians' understanding of the pathophysiology of post-operative hyponatremia, and it may help to serve as a screening tool for these patients in the future.