A post-operative fluid restriction protocol reduces the incidence of delayed hyponatremia following trans-sphenoidal pituitary surgery.

PURPOSE: The study assessed the effect of a postoperative fluid restriction on the incidence of delayed hyponatremia (DH) following transsphenoidal pituitary surgery (TSS). The incidence of DH in the prospective cohort was compared to that of a published retrospective cohort from our centre managed according to the standard postoperative protocol without fluid restriction.

METHODS

This prospective interventional study included patients aged ≥18 years who underwent TSS for pituitary neuroendocrine tumors (PitNETs). A structured postoperative fluid restriction of ≤1.5 L/day was implemented from post-operative day 5 (POD5) to POD14, with daily intake/output monitoring. Serum sodium was measured at defined postoperative intervals. DH incidence in the prospective cohort was compared with a previously published retrospective cohort managed without fluid restriction. Patient adherence and satisfaction were assessed using a study-specific questionnaire.

RESULTS

The study included 78 patients with a mean(SD) age of 42.6(11.9) years. Seventy-two (92.3%) patients had macroadenomas and 35.9% of the tumors were invasive. Twelve (15.4%) patients developed early transient AVP deficiency. Eleven (14.1%) patients developed DH between POD 5-14, compared to 36% in the retrospective cohort (p = 0.001). None in the prospective cohort required readmission or prolonged hospitalization for hyponatremia and the hyponatremia resolved with further tighter fluid restriction. Seven patients developed mild asymptomatic hypernatremia/increased serum osmolarity which resolved with relaxation of fluid intake.

CONCLUSION

A structured fluid restriction protocol of ≤1.5 L/day in the post-operative period may be safe and effective in reducing the incidence of delayed hyponatremia and readmissions following transsphenoidal pituitary surgery for PitNETs in a tropical setting.