Numbers
- 20% of SAH
- With 30–60% of these showing no impairment of consciousness
- 3% without initial hydrocephalus develops it within 1 week
Acute HCP: Obs(x) HCP
Pathophysiology
- Blood interfering with CSF flow through the
- Sylvian aqueduct
- Fourth ventricle outlet
- Subarachnoid space
- Blood interfering with reabsorption at the arachnoid granulations.
Risk factors
2018 Paisan et al
- Older age (P = .001)
- IVH (P = .004)
- Higher WFNS grade (P < .001)
- Surgical aneurysm treatment (P = .002)
- Angiographic vasospasm (P = .005)
Adams et al 2016:
- Recursive partitioning analysis of shunt risk in aneurysmal subarachnoid hemorrhage patients
Keong et al. 2012 (Silver study)
- Patient who had EVD infection had 2x risk of Shunting
- 45.7% vs 19.7%
Rao et al 2019
- Early removal of EVD can
- Reduce LOS
- Reduce complications
- Non functioning
- Infection rates
- Reduce CSF diversion rates (shunting rates)
- Theory is if it is too low you reduce CSF reabsorption through arachnoid villi and making it easier to block.
Greenbergs
- Old age
- CT:
- Increased risk
- Intraventricular blood
- Diffuse subarachnoid blood
- Thick focal accumulation of subarachnoid blood
- Not associated with it
- Intraparenchymal blood did not correlate with chronic HCP
- Patients with a normal CT had a low incidence
- HTN
- On admission
- Prior to admission (by history), OR
- Post-op
- By location:
- Post circulation aneurysm: higher association
- MCA aneurysm: lower association
- Miscellaneous:
- Hyponatremia
- Patients whowere not alert on admission
- Use of preoperative antifibrinolytic agent
- Low Glasgow outcome score
Treatment
- 50% improve spontaneously
- EVD
- Indication:
- Poor Hunter and Hess grade (Grade 4/5)
- Large ventricles may be symptomatic from the HCP
- Caused 80% of improvement in patient whom it was used.
- Olson et al 2013
- RCT: EVD complications higher in comparing continuous 53% versus intermittent 23% CSF drainage
- The study was stopped early because of the superiority of intermittent drainage without any difference in the risk of DCI.
- Keep ICP at 15-20mmHg to avoid rapid rise in transmural pressure (systolic BP - ICP)
- There may be an increased risk of aneurysmal rebleeding in patients undergoing ventriculostomy shortly after SAH especially if performed early and if ICP is lowered precipitously.
Chronic HCP: Communicating HCP
- Due to
- Pia-arachnoid adhesions
- Permanent impairment of arachnoid granulation
- 50% Acute HCP → Chronic HCP
- 8–45% of all ruptured aneurysm patients
History associated
- Intraventricular bleed
- Unsure whether ventriculostomy inc or dec risk of shunt
- Positive association between Fisher grade and the likelihood of requiring CSF diversion for chronic hydrocephalus.
- Age (2% increase/year),
- Comorbidity score (presence of DM, HTN, or alcohol abuse)
- Admission type
- Hospital aneurysm volume (high > low)
- Treatment type (clip versus coil) has also been studied with no clear advantage for one modality over the other
Weaning of EVD: Klopfenstein et al 2004
- There was no difference in the rate of shunt placement between those who underwent rapid weaning (< 24 hrs) versus gradual weaning (96 hrs) of the EVD (63.4% rapid versus 62.5% gradual).
Treatment: Permanent CSF diversion
- Subjective
- Lack of improvement from a neurological plateau
- Deterioration in the presence of ventricular dilation, often with periventricular lucencies, rounding of the frontal horns, and obliteration of the cortical sulci.
- Endoscopic third ventriculostomy is an alternative to permanent shunting that requires further investigation
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