Increased Intracranial Pressure Mary Ann Reilly BSN, MS, CRRN Santa Clara Valley Medical Center, Rehab Nurse Manager
In 2004 the SJ Mercury wrote: "As he was giving his speech he stumbled slightly and then he started to perspire a bit. I thought almost immediately that something is not right.“ • His repeated vomiting prompted paramedics to treat him with oxygen and monitor his heart for half an hour -- routine care for a sudden food-borne illness
The initial suspicion that Mayor Ron Gonzales had food poisoning Wednesday night shows just how difficult some strokes are to detect -- and experts say it offers a warning to people who might find themselves with similar symptoms.
Gonzales' type of stroke is called an intraventricular hemorrhage. • This means that a blood vessel had broken and was leaking into the ventricle, which carries spinal fluid.
So what’s the big deal? • Skull
Components of Cranial Vault • Meninges • Dura • Arachnoid • Pia • Brain • Brain tissue 80-88% • Blood • Blood 2-11% • CSF • CSF 9-10%
Blood • 15-20 of the cardiac output • 20-25% of all oxygen inspired • 750cc/min • 80% from carotid arteries • 20% from vertebral • Circle of Willis is collateral circulation • No sugar/fat/oxygen storage
Autoregulation • When intra-cranial pressure begins to rise, the body’s own compensatory mechanisms include decreasing the production of CSF and restricting the blood flow to the brain(by vasoconstriction).
Autoregulation • Self Regulated • PCO2 (carbon dioxide) vasodilator • For every 1mmHg change in PCO2 there is a 1-2cc change in blood flow per 100 GMs of brain • (1300-1400Gms avg. wt.) =s [750 +65] or [750 + 130] • Diameter of vessels • Hypercapnia: Increases CBF • Hypocapnia: Decreases CBF
Intercrainial Pressure Regulation • When BP increases, cerebral arterioles constrict to keep blood entering brain at steady rate. • When BP falls, cerebral arterioles dilate to increase blood flow to brain
Intercrainial Pressure Regulation • Metabolic regulation—changes in O2 and CO2: Low O2 and increased CO2 cause vasodilation CSF regulation—decreased production or increased reabsorption decreases ICP.
Factors Affecting CBF • Viscosity of the blood • Seizures • Anemia • Drugs
CSF • 125-150 cc clear fluid • 500cc produced per day • 20cc per hour • Replaced 4-7 times per day • Function • Protection, cushions • Waster disposal • Nutritional support (2/3 bodies BS)
CSF Pressure • Norm • 1-15 mmHg or <200mm H2O • Low pressure • Dehydration • Increased pressure • Val Salva,Tumor, Subdural Hematoma, Subarachnoid Hemorrhage, Infections, Hydrocephalus
Symptoms of Increasing ICP • Headache • Visual changes • Nausea • Vomiting • Behavior changes • Changes in LOC • Seizures
Symptoms • Aniscoria • Hemiparesis • Vital sign changes • Cushing Triad
Cushing’s Triad • Vital Sign Changes in ICP— • Systolic pressure increases (widened pulse pressure results). • Slowing of heart occurs—bradycardia (occurs as result of reflexive slowing in response to increased systolic pressure) • Respiration changes—becomes slowed
Could it be? • Difficulty speaking • Blurred vision • Hypertension • Shallow rapid breathing • Visual disturbances • Paresthesia • Hypoglycemia
OR? - Confusion • Lethargy • Nausea & Vomiting • Coma • Seizures • Syndrome of Inappropriate ADH
OR? • Changes in LOC • Nausea & Vomiting • Irritability • Disorientation • Personality changes • Seizures • Fluid Overload
OR? • Street drug • Alcohol withdrawal • Over dose • Diabetic ketoacidosis • Hypervitiaminosis A • Drug • www.merck.com/mrkshared/mmanual/section1/chapter3/3c.jsp
Diagnosis of Increased Intracranial Pressure • Overt symptoms • Papilledema • Nuchal rigidity • Lumbar Puncture***
Lumbar Puncture • Contraindicated • Focal signs • Intracranial mass • Papilledema • Cardiorespiratory compromise • Infection of skin
Rational for Contraindication • A simple analogy Performing a LP in the presence of I-ICP, may result in herniation
Herniation • Tentorium • Midbrain and diencephalon through the tentorium • Uncal • Tonsillar • Cerebellar tonsils through the foramen magnum
Diencephalic Stage • Confused and drowsy • Constricted pupils • Gaze palsies
Mesencephalic Stage: • Unconscious • Decerebrate posturing • Dilated pupils • Hyperventilation
Pontine Stage • Unconscious • Decerebrate posturing • Constricted pupils • Irregular breathing
Decorticate posture • Indicated by rigidity, flexion of the arms, clenched fists, and extended legs. The arms are bent inward toward the body with the wrists and fingers bent and held on the chest. Presence of this type of posturing implies severe damage to the brain with immediate need for medical attention.
Decerebrate Posturing • Internal rotation and extension of the arms & lower limb extension • Due to midbrain compression as the brainstem is further compressed
Medullary Stage • Unconscious • Flaccid • Loss of homeostatic control: • Increase heart rate • Decrease blood pressure • Hyperthermia • Cheyne-Stokes breathing
Cheyne-Stokes • Breathing describes a waxing and waning ventilation, sometimes with periods of apnea, that occur in cycles. • It is due to a delay in the medullary chemoreceptor response to blood gas changes
Common Causes of I-ICP • Vascular abnormalities • AV malformations, aneurisms, stroke • Diffuse cerebral ischemia • Closed head trauma, shaken baby, vasospasm • CNS infections • Tumors • Trauma • Obstruction of CSF flow
Intra Cerebral Hemorrhage
Crainial defect with midline shift
The Monroe-Kelle Hypothesis states that an increase in the volume of one component (blood, brain tissue, CSF) must be accompanied by a decrease in another component if intracranial pressure is to remain constant. The CSF and blood volume are the compartments that most easily change to accommodate changes in pressure. Interventions to prevent secondary brain injury follows these principles and focuses primarily on cerebral blood flow and drainage.
Management / Trauma • Rapid transportation • Early intubation • Aggressive resuscitation • Immediate CT • ICP monitoring
CAT Scans • Sensitivity for visualizing blood approximately 96% • Visualizes • Fractures • Hematomas
Operative Management • Burr holes • Intra-operative ultra sound • Surgical evacuation of mass lesion • Craniotomy • Craniectomy • Ventricular drainage http://www.trauma.org/neuro/neuromonitor.html