Hyponatremia and dehydration due to natriuresis after subarachnoid hemorrhage are related to symptomatic vasospasm. Therefore, most institutions are currently targeting euvolemia and eunatremia in subarachnoid hemorrhage patients to avoid complications 1).
1)
Uozumi Y, Mizobe T, Miyamoto H, Ashida N, Katsube T, Tatsumi S, Nakamura M,
Kohmura E. Decreased serum sodium levels predict symptomatic vasospasm in
patients with subarachnoid hemorrhage. J Clin Neurosci. 2017 Dec;46:118-123. doi:
10.1016/j.jocn.2017.08.037. Epub 2017 Sep 5. PubMed PMID: 28887070.