Effectiveness of dietary diabetes insipidus bundle on the severity of postoperative fluid imbalance in pituitary region tumours: A randomized controlled trial

Aim: To test the effectiveness of nurse-led dietary diabetes insipidus (DI) bundle on the severity of postoperative fluid imbalance in pituitary region tumours.

Design: Blinded randomized controlled trial.

Methods: Patients aged 18-65 operated for sellar-suprasellar tumours in an Indian tertiary care centre were enrolled through total enumeration sampling and underwent randomization with allocation concealment during Sep 2018-Feb 2019. Pre-operative DI, postoperative ventilation, renal failure or decompensated diabetes mellitus were excluded. Patients in the intervention group received a nurse-led DI bundle (validated by three Delphi rounds) with four dietary components: intake of only water during thirst and avoidance of the following-added salt, high-protein foods and caffeinated drinks. Treating clinicians and the investigator assessing outcome were blinded about enrolment. Urine output, serum sodium, vasopressin requirement and hospital stay were assessed as primary outcomes. The outcome measures were monitored daily till the 6th postoperative day. Analyses were performed on 'intention-to-treat' basis, irrespective of compliance. Independent t-test and Chi-square test were used.

Results: Of the initial 63 patients, 50 fulfilling criteria were randomized to two groups and assessed over six days yielding 150 patient-days per group. There were no significant baseline differences between groups. The mean daily urine output was significantly lower in the DI bundle group than in control, both overall and among endonasal operated pituitary adenomas [3000.09(462.7) vs. 4095.71(896.4)ml & 2987.14(419.5) vs. 4064.73(1051)ml], with the greatest difference on the second postoperative day. Though hypernatraemia in controls became most prominent during days 2-3 and resolved in a week, it was significantly lower in the intervention group (12.7% vs. 30.7% overall, 11.4% vs. 29.4% endonasal adenomas). The need for vasopressin analogues and hospital stay were also significantly lower with DI bundle (p < 0.001).

Conclusion: This is probably the first ever report of dietary DI bundle among operated pituitary patients, which seem to flatten the DI trend with significant benefits in polyuria, hypernatraemia, vasopressin requirement and hospital stay.

Trial registration: CTRI/2018/07/015127 of ICMR.

Impact: The nurse-led dietary DI bundle has effectively reduced the severity of DI among operated pituitary patients with significant benefits in polyuria, hypernatraemia, vasopressin requirement and hospital stay. Its implementation is simple and easy to carry out, especially in resource-constrained institutions, where continuous monitoring and repeated serum sodium estimation are difficult.