tom bleck - subarachnoid hemorrhage: what matters?

SNACC 2015:Subarachnoid Hemorrhage:

What Matters?

Thomas P. Bleck MD MCCM FNCSProfessor of Neurological Sciences, Neurological Surgery, Internal Medicine, and Anesthesiology, Rush Medical College; and

Director, Clinical Neurophysiology, Rush University Medical Center

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Disclosures• I am a current member of the ABIM Critical Care Subspecialty

Exam Committee.– To protect the integrity of Board Certification, ABIM enforces strict

confidentiality and ownership of exam content.– As a member of an ABIM exam committee, I agree to keep exam

information confidential.– As is true for any ABIM candidate who has taken an exam for

Certification, I have signed the Pledge of Honesty in which I have agreed not to share ABIM exam questions with others.

– No exam questions will be disclosed in my presentation.

Standard disclosures • Research support from NINDS, AHA, Zoll• Consultant for USAMRICD (nerve agent protection)• DSMB chair for Sage phase 3 trial of allopregnenolone in

RSE• DSMB member for a trial of ketogenic diet in RSE• DSMB chair for a trial of intraventricular nimodipine in

SAH

• Many of the treatments discussed are not approved by the FDA

SAH: What matters?

1. Rapidly identify patients with aneurysmal SAH and secure their aneurysm(s) quickly

2. Lower MAP before securing the aneurysm but not afterwards

3. Detect and manage early complicationsa. Stress cardiomyopathyb. Neurogenic pulmonary edemac. Cerebral salt wasting

SAH: what matters?

4. Detect vasospasm early a. Clinicalb. Electrophysiologic c. Sonographicd. Radiologic

5. Manage clinical vasospasm aggressivelya. Augment pressure and flowb. Angioplasty and IA vasodilators

Critical care issues: rebleeding

• Unsecured aneurysms:– 9% – 17% rebleed on day 0, then– 1.5%/day for next 13 days [ up to 36% for 2 weeks]

• Antifibrinolytic therapy (e.g., aminocaproic acid)– may be useful between presentation and early surgery

• Blood pressure management– labetalol, hydralazine, nicardipine

• Analgesia• Minimal or no sedation to allow examination

Radiographic diagnosis of vasospasm• Only half of patients with angiographic vasospasm

have clinical findings related to the arteries involved• DSA is currently the standard method

– Good definition of large and medium vessels– Allows angioplasty and intra-arterial therapy

• CTA for the diagnosis of vasospasm is increasing in use– Distal spasm may be more difficult to detect by

CTA• What about ‘microvasospasm?’

Critical care issues: vasospasm and delayed ischemic damage

• Prophylaxis– clot removal– volume repletion

• prophylactic volume expansion not useful– nimodipine 60 mg q4h x 14 days

• relative risk of stroke reduced 0.69 (0.58-0.84)– Probably neuroprotection rather than a vascular effect

• nicardipine 0.075 mg/kg/hr is probably equivalent

Stroke 2000

Critical care issues: vasospasm and delayed ischemic damage

• Management– volume expansion

• rarely achieved– induced hypertension– cardiac output augmentation

• dobutamine or milrinone• intra-aortic balloon pump

– angioplasty– verapamil or nicardipine (no longer use papaverine)– intrathecal or intraventricular NO donors

Lancet 2012

Cerebral salt wasting: pathophysiology

• volume depletion puts SAH patients at risk for stroke from vasospasm– Wijdicks et al (1985) showed that volume restriction

(as one would do for patients with SIADH) doubled the rates of stroke and death attributable to vasospasm

Critical care issues: neurogenic pulmonary edema

• Symptomatic pulmonary edema occurs in about 20% of SAH patients– detectable oxygenation abnormalities occur in 80%

• Potential mechanisms:– hypersympathetic state– cardiogenic pulmonary edema– neurogenic pulmonary edema

• Management

Seizures in SAH patients

• about 6% of patients suffer a seizure at the time of the hemorrhage– distinction between a convulsion and decerebrate posturing may be

difficult • postoperative seizures occur in about 1.5% of patients

despite anticonvulsant prophylaxis • remember to consider other causes of seizures (e.g.,

alcohol withdrawal)

Seizures in SAH patients

• patients developing delayed ischemia may seize following reperfusion by angioplasty

• late seizures occur in about 3% of patients

SAH prognosis

• Sudden death prior to medical attention in about 20%

• Of the remainder, with early surgery– 58% regained premorbid level of function

• as high as 67% in some centers– 9% moderately disabled– 2% vegetative– 26% dead

For slides email

tbleck@gmail.com