title: Early awareness of cerebrospinal fluid hypovolemia after craniotomy for microsurgical aneurysmal clipping.
abstract: BACKGROUND
  Mild cerebrospinal fluid (CSF) hypovolemia is a well-known clinical entity, but critical CSF hypovolemia that can cause transtentorial herniation is an unusual and rare clinical entity that occurs after craniotomy. We investigated CSF hypovolemia after microsurgical aneurysmal clipping for subarachnoid hemorrhage (SAH).
  
  
  METHODS
  This study included 144 consecutive patients with SAH. Lumbar drainage (LD) was inserted after general anesthesia or postoperatively as a standard perioperative protocol. CSF hypovolemia diagnosis was based on three criteria.
  
  
  RESULTS
  Eleven patients (7.6%) were diagnosed with CSF hypovolemia according to diagnostic criteria in a postoperative range of 0-8 days. In all patients, signs or symptoms of CSF hypovolemia improved within 24 hours by clamping LD and using the Trendelenburg position.
  
  
  CONCLUSIONS
  As a cause of acute clinical deterioration after aneurysmal clipping, CSF hypovolemia is likely under-recognized, and may actually be misdiagnosed as vasospasm or brain swelling. We should always take the etiology of CSF hypovolemia into consideration, and especially pay attention in patients with pneumocephalus and subdural fluid collection alongside brain sag on computed tomography. These patients are at higher risk developing of pressure gradients between their cranial and spinal compartments, and therefore, brain sagging after LD, than after ventricular drainage. We should be vigilant to strictly manage LD so as not to produce high pressure gradients.
authors.affiliation: Department of Neurosurgery, National Hospital Organization Nagasaki Medical Center, Kubara-2-1001-1, Omura-city, Nagasaki 856-0812, Japan. kawahara@nmc.hosp.go.jp
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawahara
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tsutsumi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsunaga
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takahata
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ono
authors.forename: Keisuke
authors.initials: K
authors.lastname: Toda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Baba
mesh_terms: D000368:Aged; D001929:Brain Edema / Q000150:complications / Q000601:surgery; D015170:Cerebrospinal Fluid Pressure / Q000502:physiology*; D003399:Craniotomy / Q000009:adverse effects*; D004322:Drainage / Q000379:methods; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D011183:Postoperative Complications / Q000601:surgery; D013345:Subarachnoid Hemorrhage / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods