Management of Increased ICP

1. Management of Increased ICP PICU Resident Talk Stanford School of Medicine Pediatric Critical Care Medicine June 2010

2. Objectives After this lesson, the participant will be able to: • Describe the principles of the Monro-Kellie Doctrine • Calculate cerebral perfusion pressure using MAP and ICP • List key management strategies for increased ICP

3. Basic Principles • Monro-Kellie Doctrine • The skull has a fixed volume • The skull contains • Brain matter • Cerebrospinal fluid • Blood • Therefore: An increase in the volume of one must be compensated by a decrease in the volume of the others or an increase in ICP will occur • Cerebral Perfusion Pressure • CPP = MAP - ICP

4. A mass will eventually cause an increase in ICP An ICP > 20 is associated with icreased morbidity and mortality

5. Aims of Management • Maintain cerebral perfusion pressure and support blood pressure • Decrease brain metabolism • Decrease the pressure!!

6. Hypotension is Associated with Worse Outcomes Kokoska. J Pediatr Surg. 1998 Feb;33(2):333-8.

7. Maintaining Adequate Brain Oxygenation • Maintain cerebral perfusion • Minimum CPP > 40 mmHg (PCCM guidelines) • Target CPP > 45-50 mmHg • Adult goal CPP > 65 mmHg • Decrease cerebral metabolism • Keep patient adequately sedated and analgesed • In extreme cases, use a pentobarbital induced coma

8. 5 Ways to Decrease Intracranial Pressure Using the Monro-Kellie Doctrine • Enhance venous drainage • Elevate head 30° • If in a cervical collar, check fit • Hyperosmolar therapy • Hyperventilation • CSF Drainage • Decompression

9. Hyperosmolar Therapy • Goal is to increase serum osmolality to draw water out of brain parenchyma • Mannitol • 0.5 - 1g/kg • 3% Saline • Every 1.5 cc/kg will increase Na by ≈ 1 mEq/L • Known to have a longer lasting effect • In general, check Na2+ and osmolality q6h • Target Na2+ 150-160 • Target osmolality > 300

10. Hyperventilation Causes a Decrease in Cerebral Blood Flow PCO2 30 pCO2 45 Skippen. Crit Care Med. 1997 Aug;25(8):1402-9

11. Use of Hyperventilation • Worse long-term outcome • Target normocapnea • Works for acute spikes in ICP • Target pCO2 of about 35 • Avoid hypercapnea

12. CSF Drainage • Neurosurgical Procedure • Always push for an EVD, not just an ICP monitor • Therapeutic AND diagnostic • Can stay in long-term (no drift) • Requires INR < 1.5 and PLTS > 100K

13. Decompressive Craniectomy • Done infrequently • Usually done at an OSH prior to transfer OR in conjunction with hematoma evacuation • Remember to save the bone flap for reimplantation later http://www.rescueicp.com/Image533554-copy.jpg

14. Avoid the Bad “H”s • Hypotension • Hypoxia • Hyponatremia • Hypervolemia • Hyperglycemia • Hyperthermia • Hypermetabolism (seizures, agitation)

15. Summary of Key Points • Many of the goals of increased ICP management are based using the Monro-Kellie Doctrine to our advantage • Goal ICP < 20 mmHg • Hyperventilation is not a long-term strategy • CPP = MAP – ICP; Maintain CPP > 40 mmHg • Goal Na2+ 150-160 • Avoid the bad “H’s”