Post-Operative Water Load Following Transsphenoidal Pituitary Surgery
Condition: Hyponatremia; Pituitary Adenoma
MeSH terms: Adenoma; Pituitary Neoplasms; Pituitary Diseases; Hyponatremia
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      Current standards are for screening of all post-operative transsphenoidal pituitary patients
      for sodium abnormalities in the POD(post-operative day)7-14 window. At the Barrow
      Neurological Institute, physicians have instituted a universal screening protocol for all
      post-operative patients wherein all patients have a serum sodium level drawn on POD5-7 and
      attempts are made to manage mild to moderate hyponatremia on an outpatient basis.This
      screening protocol has effectively identified delayed post-operative hyponatremia, however,
      it has yet to reduce readmissions for hyponatremia in these patients. The researchers propose
      that implementing a water load test on POD1 may facilitate outpatient screening in three
      ways: 1) The water load may identify a subset of patients who have appropriate water and
      sodium regulation after surgery and do not require close monitoring of outpatient sodium
      levels. 2) The water load may identify a subset of patients who are at risk for delayed
      hyponatremia and would benefit from strict counseling and closer outpatient monitoring. 3)
      The water load may identify a subset of patients with a moderate to severe reduction in serum
      sodium in response to the water load, and these patients may benefit from further monitoring
      in the hospital prior to discharge. If any of these scenarios hold true, this may change the
      way physicians monitor and treat patients following transsphenoidal surgery in the future.
      Furthermore, this protocol could be readily expanded to other neurosurgery practices and
      could facilitate care for future patients undergoing transsphenoidal pituitary surgery.
    

Intervention name(s): Water Load (WL) Post-Operative Day 1
Intervention type(s): Other
Intervention description(s): Patient will have normonatremic 0600 hr sodium level (Serum Sodium = 135 - 145 mmol/L), ability to safely take water by mouth, and cleared to continue by treating surgeon. WL will be calculated (20 mL/kg body weight) and supplied at the bedside. Vasopressin level will be determined. Patient will have 30 minutes to consume WL, or will be excluded. Included patients will have data collected as follows: 1 hour - serum sodium, urine output; 2 hour - serum sodium, urine output, vasopressin level; 6 hours - serum sodium, urine output.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Supportive Care
Keywords: transsphenoidal pituitary surgery