Spontaneous Subdural Hematoma

Most acute SDH are due to trauma from laceration of bridging veins in the subdural space.  Nontraumatic cases are rare (incidence rate 3-5%) and predominantly affects adulst in 5th to 7th decade.

 

Predispoding factors to spontaneous SDH:

  1. vascular abnormalities – cerebral aneurysm, AVM, dural AVF
  2. hematological disorders
  3. anticoagulant therapy

 

Mechanisms of nontraumatic SDH:

  1. aneurysms:
    1. previous minor hemorrhages fixes an aneursym to local arachnoid adhesions –> results in bleeding directly into subdural space when arachnoid tear occurs after aneurysm rupture
    2. hemorrhage under high pressure leading to pia arachnoid rupture and extravasation into subdural space
  2. sudden increase in intravenous pressure (Valsalva) – rupture of bridging dural veins
  3. intracranial hypotension – systemic vascular hypotension after exercise

 

Diagnostics:

  • Modality of choice:  CT;  cerebral angio to exclude vascular abnormalities
  • Other investigations:  coagulation tests

 

 

References

Wang, Hui Sun, Seok Won Kim, and Sung Hoon Kim. “Spontaneous Chronic Subdural Hematoma In An Adolescent Girl”. J Korean Neurosurg Soc 53.3 (2013): 201. Web.

 

Elements of the external ventricular drain (EVD) infection control protocol for EVD placement.

  • A wide area of the patient’s hair (A) is clipped to an area large enough to eventually dress with a medium-sized transparent dressing film.
  • Chlorhexidine-alcohol is then applied in a first skin preparation (A, left).
  • Full patient draping is followed by a second chlorhexidine-alcohol skin preparation with the surgeon wearing gown, gloves, cap, and mask (A, center), and full barrier precautions are used throughout (A, right).
  • A minocycline/rifampin antibiotic-impregnated EVD catheter is tunneled 3 to 5 cm and then secured with a curvilinear line of surgical staples (B).
  • After Benzoin tincture is applied to the skin broadly and allowed to fully dry, a chlorhexidine-eluting patch is applied over the exit site (without wrapping the patch around the catheter), and a medium-sized transparent dressing film is applied (B).
  • The borders of the transparent dressing film and the catheter are further secured with adhesive strips (B).
  • Additional information on placement and dressing available at: http://www.cleanbrain.org

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Elements of the external ventricular drain (EVD) infection control protocol for EVD manipulation (cerebrospinal fluid draws or flushing). Supplies are arranged outside the sterile field (A): 70% isopropyl alcohol, a kidney basin, and several 10- mL vials of sterile, preservative-free normal saline. Supplies are then opened onto a sterile field created with a large sterile drape over the patient (B): several chlorhexidine-alcohol swabs, several sterile 10-mL syringes, a surgical sponge, and sterile Luer-fitting port caps. Before gowning and gloving, the 3-way stopcock on the EVD port is turned to 45 (“off” to all directions) and submerged in 70% isopropyl alcohol solution (C). (This step is not performed on the sterile field.) The intensive care unit (ICU) nurse holds the EVD line over the sterile field without allowing the tubing to contact the field (D), and the physician dons cap, mask, sterile gown, and sterile gloves. The physician then cleanses the entire region of the port with a chlorhexidine-alcohol swab. The old port cap is discarded; the port is inverted; and fluid in the port is shaken out onto a surgical sponge (E). The port is cleaned again and then filled with chlorhexidine-alcohol solution (F). The port is inverted, and chlorhexidine-alcohol solution is shaken out onto the surgical sponge (G). Steps F and G are repeated several times. The physician uses the sterile 10-mL syringes to draw up sterile, preservative-free normal saline in sterile fashion from the ICU nurse. The port is rinsed with sterile, preservative-free normal saline, and the port is inverted to discard (H). The rinse step is repeated several times. A sterile 10-mL syringe is then attached to the port for CSF draw or flushing (I). Additional information about EVD manipulation techniques available at: http://www.cleanbrain.org.

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External Ventricular Drain Infection Control Protocol

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References

Flint, Alexander C. et al. “A Simple Protocol To Prevent External Ventricular Drain Infections”.Neurosurgery 72.6 (2013): 993-999. Web.

Admission Criteria for NSCU

    • Neurovascular-Ischemic
      • Large hemispheric infarction defined as greater than 2/3 vascular territory and/or early signs of shift or impending herniation.
      • Cerebellar/posterior fossa infarction with threat of herniation or brainstem compromise
      • Cerebral edema requiring hyperosmolar (3% saline) therapy and/or ICP monitoring
      • Fluctuating exam suggesting of ongoing ischemia; induced hypertension
      • Status post interventional therapy
    • 2 Neurovascular-hemorrhagic
      • infra- or supra-tentorial spontaneous intracerebral hemorrhages that require ICU admission (refer to ICH Stroke Unit admission guidelines)
      • Aneurysmal/non-Aneurysmal subarachnoid hemorrhage
      • AVM post intervention/embolization and/or resection
      • Non-ruptured aneurysm coiling/clipping
    • Trauma
      • Patients with abnormal imaging and depressed GCS in setting of traumatic brain injury
      • Acute subdural/epidural hemorrhages
      • Chronic subdural hemorrhages > 10cm in thickness or <10cm in thickness in presence of neurological symptoms
    • Tumors
      • Evidence of vasogenic edema, shift with risk of herniation or neurological compromise
      • Osmotherapy/ICP monitoring for cerebral edema
      • Post-op craniotomy
    • Spine
      • Acute cord injury-trauma, malignancy
      • Post-operative cervical/thoracic fusion/lami with risk of respiratory decompensation
    • Status Epilepticus-convulsive or nonconvulsive
    • Neuromuscular disease
      • Guillain-Barre with change in VC and or NIF by 30% in a 24-hour period or a VC <20mg/kg or NIF <25cm H20 or evidence of autonomic instability
      • Myasthenic crisis
    • Other
      • Neurological patients with evidence of hemodynamic instability requiring vasopressor therapy
      • Neurological patients with evidence of respiratory compromise requiring mechanical ventilation
      • Neurological patients requiring invasive hemodynamic monitoring

REFERENCE:

NSUH Guidelines:  Neurosurgical Intensive Care Unit Admission Protocol.  11/18/2014

Craniotomies for Aneurysms

F our different tailored craniotomies are used for typical anterior circulation aneurysms:

  • pterional craniotomy for internal carotid aneurysms
  • Sylvian craniotomy for middle cerebral aneurysms
  • orbitocraniotomy for anterior communicating artery
  • anterior interhemispheric craniotomy for A2-callosomarginal artery aneurysms

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Two approaches are used for posterior circulation aneurysms:

  • lateral paracondylar for vertebral artery aneurysms
  • paramedian for peripheral aneurysms

 

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References

Steiger, Hans-Jakob, Nima Etminan, and Daniel Hänggi. Microsurgical Brain Aneurysms. Print.

SEPS

SEPS

SEPS = Subdural Evacuating Port System  (Medtronic)

“The SEPS™ Cranial Access Kit is indicated when access to the subdural space and evacuation of a cranial subacute or chronic hematoma or hygroma is necessary. The SEPS Cranial Access Kit consists of surgical instruments and accessories used for draining subdural fluid accumulations such as hygromas and liquid-state subdural hematomas to an external suction reservoir without touching the brain. Utilizing a minimally invasive technique, the SEPS Cranial Access Kit’s components are designed to promote gradual brain re-expansion by creating a low homogeneous negative pressure throughout the subdural space as fluid is drained to an external suction reservoir.”

Instructions for Putting a SEPS drain:

  1. perform SEPS under local or general anesthesia
  2. identify area of greatest subdural fluid thickness using CT scan or MRI
  3. prep and drape selcected site with Chloraprep
  4. Mark incision site with sterile marking pen
  5. make a 5 mm incision through skin, subcutaneous tissue, galea and periosteum.
  6. apply holzheimer retractor to expose skull
  7. attach safety stop collar to drill bit
  8. secure drill bit with safety stop collar to hand drill
  9. place drill into chuck, hold chuck motionless while rotating handle clockwise.
  10. create twist drill hole through outer and inner tables of the skull
  11. incise dura, remove all exposed dura and subdural membranes form twist drill hole before inserting evacuating port (use #11 scalpel blade and forceps or unipolar cautery)
  12. Do not insert evacuating port until fluid is flowing freely from twist drill hole
  13. remove self-retaining scalp retractor and insert evacuating port by twisting clockwise. (4 turns will seat port securely into skull above inner table.
  14. evacuating port should never protrude beyond inner table
  15. attach silicone tubing to evacuating port and to suction reservoir bulb
  16. apply low homogenous negative pressure with suction reservoir bulb
  17. close wound around evacuating port
  18. fluid evacuation generally completed within 24-48h.  Monitor suction reservoir blood and empty as needed with repeated reapplication of negative pressure.

 

 

REFERENCE:

Click to access mns-seps-ifu.pdf

ICU Liberation – the ABCDE bundle / SAT and SBT

The ABCDE Bundle: Tools for Implementation

  • “Wake Up and Breathe” Protocol
  • Confusion Assessment Method for the ICU (CAM‐ICU) Flowsheet
  • Intensive Care Delirium Screening Checklist (ICDSC)
  • Pediatric CAM‐ICU – Worksheet for Daily Delirium Assessment
  • Progressive Mobility Protocol
  • Exercise/Mobility Safety Screen and Therapy
  • Journal Club Exercises

 

“Wake Up and Breathe” Protocol Spontaneous Awakening Trials (SATs) + Spontaneous Breathing Trials (SBTs)

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CAM ICU Flowsheet:

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REFERENCES:

http://www.icudelirium.org/docs/WakeUpAndBreathe.pdf  WakeUpAndBreathe

http://www.aacn.org/WD/CETests/Media/ABCDE–Tools%20for%20Implementation.pdf  ABCDE–Tools for Implementation

Platelet Response / ARU / PRU

VerifyNow for Clopidogrel:

  • Values less than 194 PRU are specific evidence of a P2Y12 inhibitor effect

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VerifyNow for Aspirin:

  • ≤ 549: Evidence of platelet dysfunction due to aspirin
  • > 550: No evidence of aspirin-induced platelet dysfunction

 

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ASA-specific VerifyNow uses arachidonic acid as an agonist for platelet aggregation onto fibrinogen-coated beads.

VerifyNow (P2Y12) uses adenosine diphosphate and is more commonly utilized to detect platelet dysfunction due to clopidogrel.

Degree of platelet aggregation is recorded as aspirin reaction units (ARUs) or P2Y12 reaction units (PRUs).

Abnormally functiong platelets are defined as ARU <550 or PRU 208 (U of Cincinnati lab normal value, cutoff not universally defined).

 

VerifyNow Reference Guide

Clinical Value of the VerifyNow System

 

REFERENCES:

Click to access mvn0005_-_verifynow_pocket_guide_1.pdf

Click to access CLMA_Educ_Day_Presentation_-VerifyNow_2-18-14.pdf

Martin, G., Shah, D., Elson, N., Boudreau, R., Hanseman, D., Pritts, T., Makley, A., Foreman, B. and Goodman, M. (2018). Relationship of Coagulopathy and Platelet Dysfunction to Transfusion Needs After Traumatic Brain Injury. Neurocritical Care.

 

EEG Waves

  • Diffuse background slowing = seen in almost all cases of depressed level of consciousness
  • Continuous spike and wave activity in a stuporous or confused patient = nonconvulsive status epilepticus
  • Triphasic wave = hepatic encephalopathy, renal and pulmonary failure
  • PLEDS (periodic lateralizing epileptiform discharges) = herpes encephalitis and large destructive hemispheric lesions
  • Beta activity in combination with diffuse slowing = suggests overdose with barbiturates, benzodiazepines, or sedative hypnotic drugs
  • Focal spike and wave activity = a single irritative focus as in complex partial (focal) onset seizures
  • Generalized paroxysmal spike and wave activity = generalized seizures
  • Burst suppression pattern = often seen in severe hypoxicischemic brain injury with very poor prognosis
  • Electrocerebral silence = indicative of brain death

 

Reference

Rana, Abdul Qayyum, and John Anthony Morren. Neurological Emergencies In Clinical Practice. London: Springer, 2013. Print.

Gaze

  • Gaze deviation AWAY from hemiparesis : hemispheric lesion contralateral to hemiparetic side.
  • Gaze deviation TOWARD hemiparesis: pontine lesion, contralateral hemispheric seizure focus and contralateral thalamic lesion
  • Downward gaze deviation : midbrain tectum lesion. (Parinaud’s – accompanied by impaired pupillary reaction to light and convergence-retraction nystagmus)
  • Ocular bobbing : lesion of bilateral pontine horizontal gaze center (fast downward movements of both eyes with a slow return to primary position)

 

References

Rana, Abdul Qayyum, and John Anthony Morren. Neurological Emergencies In Clinical Practice. London: Springer, 2013. Print.