Oral Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Prophylactic fluid restriction prevents moderate-severe delayed hyponatraemia following pituitary surgery (#206)

Emily Brooks 1 2 , Christina Jang 1 3 , Tanya Thompson 4 , Mauli Govinna 4 5 , Annabelle Hayes 4 5 , Warrick Inder 2 , Ann McCormack 4 5
  1. Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
  2. Department of Endocrinology, Princess Alexandra Hospital, Brisbane, QLD, Australia
  3. Endocrinology, Royal Brisbane and Women's Hospital, Brisbane
  4. Garvan Institute of Medical Research, Sydney
  5. St Vincent's Hospital, Darlinghurst, NSW, Australia

Aims: Delayed hyponatraemia due to the syndrome of inappropriate antidiuretic hormone (SIAD) is the most frequent reason for readmission following transsphenoidal (TSS) pituitary surgery1. This study assessed the effectiveness and safety of prophylactic fluid restriction to prevent postoperative SIAD.

Methods: A multicentre, prospective, randomised controlled trial of adults undergoing TSS pituitary surgery between February 2021-June 2024 at St Vincent’s Hospitals, Sydney and Princess Alexandra Hospital and Royal Brisbane and Women’s Hospital, Brisbane, was performed. Participants were randomised to 1 litre/day fluid restriction from postoperative days 4-9, or control. Plasma sodium, urea and creatinine were monitored on day 7-8 and 9-10 post-operatively. Participants were asked to complete a fluid intake record and thirst scale. The primary outcome was the development of SIAD day 4-11 post-operatively. Secondary outcomes included readmission for hyponatraemia, plasma sodium 7-11 days post-operatively, adverse effects and adherence.

Results: 122 participants were randomised to fluid restriction (66) or control (56). The mean plasma sodium on day 7-8 was 136.6 mmol/L in the control group and 138.8 mmol/L in the fluid restriction group (p = 0.013) and on day 9-10 was 137.6 mmol/L in the control group and 138.8 mmol/L in the fluid restriction group (p = 0.066). 27 participants developed hyponatraemia (22.1%); 17 (25.8%) in the control group and 10 (17.8%) in the fluid restriction group (p=0.14). In the control group, 10 participants had mild hyponatraemia (Na+ 130-134 mmol/L), 5 had moderate hyponatraemia (Na+ 125–129 mmol/L) and 2 had severe hyponatraemia (Na+ <125 mmol/L). In the fluid restriction group, 9, 1 and 0 participants had mild, moderate, and severe hyponatraemia respectively. The incidence of moderate and severe hyponatraemia was significantly lower in the fluid restriction group (p = 0.049).

Conclusion: Prophylactic fluid restriction of 1 litre/day from days 4-9 post-TSS pituitary surgery reduces the occurrence of moderate-severe hyponatraemia.

  1. 1. Bohl MA, Ahmad S, Jahnke H, et al. Delayed hyponatremia is the most common cause of 30-day unplanned readmission after transsphenoidal surgery for pituitary tumors. Neurosurgery. 2016;78(1):84–90