Central diabetes insipidus (CDI),a disease caused by the decrease of AVP (a hormone involved in the control of water-electrolyte balance ) secretion and characerized by polyuria, is a common complication after neurosurgerical intervention and there is a lack of diagnostic criteria.Since the surgry casuses damage to patients' AVP-secreting neuronal cells, transient CDI (t-CDI) usually occurs 24-48h postoperatively and gradually resolves in about 10 days.However,permanent CDI (p-CDI) occurs in a small percentage of patients.Copeptin is a fragment of AVP, which has been shown to response the secretion of AVP.Multiple international studies have identified clinical applications for the use of copeptin to differentially diagnose adults with CDI , to assess electrolyte disturbances associated with AVP regulation, and to predict postoperative CDI after pituitary surgery.This study aims to investigate the trend of serum copeptin levels and its clinical value for postoperative CDI in pediatric patients after neurosurgerical intervention in ICU.

In children and adolescents, the concentration distribution of copeptin has been gradually explored in recent years,but International studies have not yet shown the trend of copeptin levels in pediatric patients after neurosurgical intervention and its value in predicting CDI.

The primary objective of this study is to investigate the trend of serum copetin levels in ICU children after neurosurgerical intervention and compare differences of copeptide levels in children with CDI (t-CDI, p-CDI) and non-CDI. The secondary objective is to evaluate the optimal detection time and CUT OFF of copeptin in predicting the postoperative secondary CDI .

Blood sampling time points of serum copeptin levels are listed as follow:

presurgery(T0), 1h (T1), 1 day (T2), 2 days (T3), 3 days (T4), 4 days (T5), 5 day (T6) after surgury.

Inclusion Criteria:

• Male and female,age ≥29 days and <18 years
• After neurosurgical intervention
• The patient agrees to comply with the requirements of the program, including follow-up visits and other related matters

Exclusion Criteria:

• Structural diseases of the genitourinary system (with the possibility of nephrogenic diabetes insipidus)
• Preoperative symptoms of diabetes insipidus
• Diabetes mellitus (HbA1c >8.5%)
• Drugs causing excessive drinking and urination (e.g., sodium-glucose cotransporter-2 inhibitors and diuretics)
• Lack of follow-up data after 3 months

Pediatric patients after neurosurgical intervention in ICU