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Acute Intracranial Hypertension

89

 

Sunit Singhi

 

A 2-year-old unconscious child was brought to the emergency department following fall from the first floor of a building. Initical Glasgow coma score was 6. Both pupils were reactive, blood pressure was 95 mmHg systolic, and heart rate was 120/min. Head CT on admission revealed multiple contusions with cerebral edema. Within 30 min of admission, blood pressure shot up to 130 mmHg, heart rate dropped to 70/min, and the right pupil got dilated.

Acute intracranial hypertension is a medical emergency requiring prompt diagnosis and management. Appropriate and timely management strategies result in better patient’s outcome in an otherwise severely debilitating or fatal disease process.

Step 1: Initiate resuscitation

Airway (A): Secure airway, do rapid sequence intubation, and maintain/induce sedation with midazolam and/or diazepam.

Breathing (B): Perform hyperventilation using Ambu bag while waiting for intubation, and maintain PaCO2 of 30–35 mmHg.

Circulation (C): Assess for euvolemia, give normal saline bolus if central venous pressure is less than 8–10 or systolic blood pressure is less than 5th percentile prior to instituting osmotic therapy.

Step 2: Understand intracranial hypertension

A.Monro–Kellie doctrine

The pathophysiology and management of AIH is based on the Monro–Kellie doctrine. Intracranial pressure (ICP) is the sum total of pressure exerted by the

S. Singhi, M.D., F.C.C.M. (*)

Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India

e-mail: sunit.singhi@gmail.com

R. Chawla and S. Todi (eds.), ICU Protocols: A stepwise approach,

709

DOI 10.1007/978-81-322-0535-7_89, © Springer India 2012

 

710

S. Singhi

 

 

brain tissue (»80%), blood volume (»10%), and cerebrospinal fluid (»10%) in the noncompliant cranial vault.

B.Normal value

ICP is not a constant value but is variable with various activities such as coughing, sneezing, and age. Single measurement is not a true representation of ICP; it needs to be measured over the period (24–72 h). Usually normal limits are taken as 5–15 mmHg.

C.Acute intracranial hypertension

AIH is a clinical condition defined as the persistent elevation of ICP of more than 20 mmHg for more than 5 min in a patient who is not being stimulated and as a threshold to define intracranial hypertension requiring treatment. Sustained ICP values of more than 40 mmHg indicate severe, life-threatening intracranial hypertension.

An algorithmic approach to management of ICP (Fig. 89.1) helps put things into perspective so that all aspects of care are attended to.

Maximize oxygenation and ventilation.

In an ICP-based therapy, the primary goal is reduction of ICP to less than 20 mmHg.

In a cerebral perfusion pressure (CPP)-based therapy, systolic blood pressure and mean arterial pressure (MAP) should be maintained to keep CPP more than 60 mmHg.

CPP = MAP–ICP; MAP = one-third systolic pressure plus two-thirds diastolic pressure.

Avoid factors that aggravate or precipitate elevated ICP.

Decrease cerebral metabolic rate.

Step 3: Start general measures

Keep temperature below 38°C (around-the-clock oral acetaminophen 15 mg/kg 6 hourly).

Glucose control—keep blood glucose between 80 and 140 mg/dL.

Avoidance of jugular venous outflow obstruction (head in midline and elevated to 30°).

Normoxia (PaO2 80–120 mmHg and SpO2 >90%) and normocarbia (PaCO2 35–40 mmHg).

Preservation of adequate sedation–analgesia.

Seizure prophylaxis (Phenytoin 20 mg/kg loading, then 5–8 mg/kg/d), for patients at high risk.

Nutrition—enteral (preferred) to be started within 72 h.

Step 4: Start first-tier ICP-specific treatments

Ventilate to normocarbia (PCO2 35 mmHg).

Sedation and pharmacologic paralysis.

Hyperventilate to PaCO2 of 30–35 mmHg (moderate and transient only, do not prolong, >6 h, and prophylactic hyperventilation).

Increase MAP.

89 Acute Intracranial Hypertension

711

 

 

Neurological examination

Signs and symptoms suggestive of raised ICP or GCS <8

Care of airway, breathing, circulation

 

If resectable

Endotracheal intubation

 

mass/hydrocephalous/bleed

CT scan/MR imaging

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Insertion of ICP catheter and ICP

 

 

 

 

Surgical resection/

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ventriculostomy/CSF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

monitoring

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

diversion/evacuation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Normocarbia

 

 

 

 

 

 

 

 

 

 

 

 

 

Head midline elevated

 

 

Minimum stimulation

 

 

 

PaCO2≈35 mmHg

 

 

 

Normovolemia

 

Prevent or treat fever

20–30°

 

 

Adequate sedation and

 

 

 

Normoxia

 

 

 

 

 

 

& seizures

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

analgesia

 

 

 

 

 

 

 

PaO2>60 mmHg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SpO2>92%

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ICP>20 mmHg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Heavy sedation

 

 

 

Osmotherapy:

 

 

 

 

 

Mild hyperventilation

 

 

 

 

 

 

 

± NM Blockade

 

 

 

Mannitol/HTS

 

 

 

 

 

PaCO2 30–35 mmHg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ICP >20 mmHg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Refractory intracranial hypertension

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Barbiturate therapy

 

 

Moderate hypothermia

 

 

Hyperventilation

 

 

 

Decompressive craniectomy

 

 

 

 

 

 

 

(32-33 C)

 

 

PaCO2 <30mmHg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 89.1 An approach to the management of intracranial hypertension. ICP Intracranial pressure, GCS Glasgow coma score, HTS hypertonic saline

Mannitol (0.25–2 g/kg IV bolus every 4–6 h; serum osmolality not >320 mOsmol/kg).

Saline infusion (3%) (loading 10 mL/kg; 0.1–1 mL/kg/h infusion; serum osmolality not >360 mOsmol/kg).

Consider ventriculostomy—drain 3–5 mL cerebrospinal fluid.

Step 5: Consider second-tier therapy if ICP is persistently high

Barbiturates coma (thiopental loading 1–5 mg/kg IV; if complete response [ICP <20 mmHg], return to first-tier agents or repeat bolus doses as necessary; if incomplete response [ICP >20 mmHg but reduction <25%], start IV 1–5 mg/ kg/h infusion or until burst suppression EEG pattern at 1–2 bursts/min).

712

S. Singhi

 

 

Moderate hypothermia (32–34°C with surface or endovascular cooling method for 24–72 h, followed by passive rewarming over 12–24 h).

Step 6: Consider third-tier therapy

Decompressive craniectomy or temporal lobectomy (if medical AIH management has failed but the patient does not have overt herniation syndrome yet).

Hyperventilation for acutely symptomatic patients may be lifesaving.

Two osmotic agents are currently in use: mannitol and hypertonic saline (3%).

Induced hypothermia is effective in reducing ICP by suppressing all cerebral metabolic activities.

Suggested Reading

1.Meyer MJ, Megyesi J, Meythaler J, Murie-Fernandez M, Aubut JA, Foley N, Salter K, Bayley M, Marshall S, Teasell R. Acute management of acquired brain injury part I: an evidence-based review of non-pharmacological interventions. Brain Inj. 2010;24(5):694–705.

There is a paucity of information regarding nonpharmacological acute management of patients with ABI. This review found strong levels of evidence for only four interventions (decompressive craniectomy, cerebrospinal fluid drainage, hypothermia, and hyperbaric oxygen).

2.Singhi SC, Tiwari L. Management of intracranial hypertension. Indian J Pediatr. 2009;76(5): 519–29.

A review article on the management of acute intracranial hypertension.

3.Latorre JG, Greer DM. Management of acute intracranial hypertension. Neurologist. 2009;15: 193–207.

The clinical manifestation and principles of management of acute intracranial hypertension are discussed and reviewed.

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