بسم الله الرحمن الرحیم

Dr.JarahzadehIntensivist

Principals of Neurocritical Care

Introduction Successful care for the neurosurgical

patient requires excellent collaboration between neurosurgeon and intensivist.

The result of a technically perfect operation can be ruined by inadequate postoperative care, and a complicated operative procedure will necessitate expert intensive care to correct abnormalities in homeostatic mechanisms and restore brain function.

Introduction The principal goal of postoperative

neurosurgical intensive care is early detection and

treatment of post-surgery complications.

The second goal is prevent secondary insults, which may

initiate or exacerbate secondary damage in a vulnerable central nervous system

Introduction

• Specific care and monitoring of the postoperative

neurosurgical patient requires accurate knowledge of the preoperative situation and the

intraoperative procedure, including the surgery,

anesthesiology, and any surgical complications.

Introduction• The goal of cardiopulmonary and respiratory

monitoring Is to ensure accurate control of systemic

hemodynamic an respiratory function, essential for optimization of cerebral oxygenation.

Invasive arterial blood pressure monitoring is

recommended with the reference point set at the same level as

intracranial pressure measurement to allow accurate calculation of CCP

Introduction

The development of cerebral herniation (tentorial

herniation/cerebellar tonsillar herniation) constitutes a neurosurgical emergency.

A rapid intervention is required prior to furthe

investigations to determine the cause

Vasojenic edema in Glioblastoma

Introduction

Treatment of patients with spontaneous intracerebral hemorrhage in a neuro-ICUneuro-ICU is associated with reduced mortality,

when compared with patients admitted to a general ICUgeneral ICU.

GOALS OFGOALS OFPOSTOPERATIVE POSTOPERATIVE

NEUROSURGICAL CARENEUROSURGICAL CARE

• The principal goal of postoperative neuro-ICU is early detection and treatment of post-surgery complications.

• The second goal is to prevent secondary insults, which may initiate or exacerbate secondary damage in a vulnerable central nervous system

POSTOPERATIVE COMPLICATIONS

PREVENTION AND MANAGEMENT OF SYSTEMIC COMPLICATIONS AFTER

NEUROSURGERY

PREVENTION AND MANAGEMENT OF SYSTEMIC COMPLICATIONS AFTER

NEUROSURGERY Deep venous thrombosis has been reported to

occur in 18% to 50% of neurosurgical cases" and pulmonary embolism in 0% to 25%

The incidence of deep venous thrombosis and pulmonary embolism incidence is particularly high in patients with brain tumor.

Existing evidence, however, does not clearly show an increased risk of clinically significant hemorrhagic complications with anticoagulant prophylaxis but does show a beneficial effect in reducing deep venous thrombosis and pulmonary embolism.

PREVENTION AND MANAGEMENT OF SYSTEMIC COMPLICATIONS AFTER

NEUROSURGERY

• This supports the administration of anti thrombotic prophylaxis prior to neurosurgical procedures in all patients, including those with intracranial hemorrhagic lesions, those with closed TBI,and high-risk trauma patients.

• Early mobilization in the postoperative phase, whenever possible, is recommended.

PREVENTION AND MANAGEMENT O NEUROSURGICAL POSTOPERATIVE

COMPLICATIONS SUPRATENTORIAL PROCEDURESPostoperative Subgaleal Hematoma• Postoperative subgaleal hematoma can occur in up to 11% of

procedures.• These hematomas generally result from either inadvertent

damage to the superficial temporal artery with inadequate hemostasis or from hemorrhage from the temporal muscle.

• If the superficial temporal artery is damaged during the operation, ligation is preferred over coagulation.

• The occurrence of subgaleal hematomas can be minimized by routine use of postoperative wound drainage for 24 hours.

• Reoperation for subgaleal hematomas is seldom necessary unless there is a communication with the intracranial compartment resulting in secondary compression of the brain

Intracranial Hemorrhage• Intracranial postoperative hemorrhage occurs in approximately 1%

of procedures and mainly concerns intra parenchymal hematomas (43-60%), epidural hematomas (28-33%), and subdural hematomas (5-7%).

• Inadequate hemostasis of meningeal arteries, blood loss from the temporal muscle, or blood loss from the bone may, however, induce a larger postoperative epidural hematoma.

• Postoperative subdural hematomas occur less frequently and may result from delayed rupture of bridging veins after a large intracerebral decompression.

• On occasion, such subdural hematomas can occur distant from the primary site of operation.• Parenchymal hemorrhages are the most frequent cause of

hematomas after supratentorial procedures and generally occur at the site of operation, particularly following partial tumor resection.

• An increase in systemic blood pressure at the end of surgery is another factor that may increase the risk of parenchymal hemorrhage.

Postoperative Brain Swelling

• Modern neuroanesthesiology techniques have diminished the incidence of peri- and postoperative brain swelling.

• Predisposing factors are hypercapnia, arterial hypertension,and obstruction of venous drainage.

• In any patient with brain swelling during the surgical procedure, the possibility of a deep hematoma should be considered and urgent postoperative computed tomography (CT) should be performed.

• Brain swelling due to vasodilation can be corrected by hyperventilation and barbiturate administration.

• Brain swelling due to cerebral edema should be preferentially treated by osmotic agents and mild hyperventilation.

Tension Pneumocephalus

• On postoperative CT scans, some air collection is generally observed.

• In rare circumstances, the postoperative rewarming of air in the intracranial compartment or continuous air leakage, due to a cerebrospinal fluid fistula of the skull base, may lead to a tension pneumocephalus, with clinical symptomatology including

A decreasing level of consciousness, signs of raised ICP, and occasionally seizures.

• Generally, postoperative air accumulations are self-limiting and do not require specific treatment.

Seizures• An epileptic seizure in the immediate postoperative period should be

considered a serious complication that may cause significant deterioration due to vasodilation, increased cerebral oxygen consumption, and increased brain edema. .

• The benefits of prophylactic anti seizure medication should be balanced against risks. In some centers, routine prophylaxis is prescribed in all patients undergoing supratentorial brain surgery.

• In others, the indications are restricted to • Cerebrovascular surgery (arteriovenous malformation,

aneurysm) • Cerebral abscess and subdural empyema • Convexity and para falcial meningiomas • Penetrating brain injury • Compound depressed skull fracture • Opinions vary on the duration of prophylactic antiseizure therapy, with

some centers recommending a treatment duration of 2 weeks and others continuing for at least 3 months

INFRATENTORIAL SURGERY

• Postoperative complications in the posterior fossa can lead to rapid deterioration due to the relatively small infra tentorial reserve capacity and the immediate compression of the brainstem,resulting in respiratory insufficiency and acute herniation.

• Irritation of the brain stem may induce large swings in arterial blood pressure, increasing the risk of postoperative hemorrhage during hypertensive episodes.

• Cranial nerves are more susceptible to damage due to surgical manipulation than peripheral nerves Lesions of the lower cranial nerves may lead to a diminished gag reflex with increased risk of aspiration and pneumonia.

• After any infra tentorial procedure, the risk of acute hydrocephalus due to obstruction at the level of the fourth ventricle is increased

• After posterior fossa surgery, some patients develop a syndrome of aseptic meningitis.

• This is characterized by meningeal symptoms:• Headaches, and an inflammatory response in the

cerebrospinal fluid in the absence of evidence for infection.

• The origin of this syndrome has not been fully clarified, but symptoms may resolve sooner with intermittent cerebrospinal fluid drainage

INFRATENTORIAL SURGERY

Intracranial pressure

ADMISSION EXAMINATION AND MONITORING IN THE INTENSIVE CARE UNIT

POSTOPERATIVE MONITORING AFTER INTRACRANIAL PROCEDURES

CLINICAL SURVEILLANCE

• Even in this era of sophisticated monitoring procedures, routine clinical examinations are essential.

• The clinical assessment has the purpose of disclosing major, life-threatening complications early after surgery, and of assessing neurologic deficits in the following hours to days that follow.

Early Evaluation

A simple check of consciousnessconsciousness

pupilspupils

Early Evaluation

GLASGOW COMA SCALE

Early Evaluation

Pupillary reactivity and Pupillary reactivity and sizesize

SYSTEMIC MONITORING:CARDIOPULMONARY , RESPIRATORY

TEMPERATURE

The goal of cardiopulmonary and respiratory monitoring • To ensure accurate control of systemic hemodynamic and respiratory function,

essential for optimization of cerebral oxygenation. • Invasive arterial blood pressure monitoring is recommended with the reference point

set at the same level as ICP measurement to allow accurate calculation of cerebral perfusion pressure (CPP).

• Hypovolemic shock is common in the setting of multisystem injury or intraoperative blood loss with inadequate replacement. • It is important to recognize that tachycardia and signs of peripheral vasoconstriction• such as skin pallor and poor capillary refill can precede a drop in blood pressure. • Treatment is rapid fluid resuscitation using isotonic crystalloid fluids, volume

expanders, small volume resuscitation (hypertonic saline),and blood transfusions.

SYSTEMIC MONITORING:CARDIOPULMONARY , RESPIRATORY

TEMPERATURE

The goal of cardiopulmonary and respiratory monitoring

• Central venous pressure monitoring can be used to guide volume resuscitation. After initial volume resuscitation, we suggest a hematocrit of approximately 30% to 33% as optimal in the acute postoperative period in patients in the neuro-ICU.

• After intracranial or spinal cord• procedures we would advocate a more liberal use of blood transfusions than generally recommended in intensive care medicine, to

promote adequate oxygenation of the central nervous system. • Cardiogenic shock due to primary loss of cardiac function is less

common in neurosurgical patients but occurs in the elderly patient with either secondary cardiac ischemia or arrhythmias.

SYSTEMIC MONITORING:CARDIOPULMONARY , RESPIRATORY

TEMPERATURE

The goal of cardiopulmonary and respiratory monitoring

• In patients with spinal distributive shock, typically the hypotension is associated with bradycardia with a pulse 35 to 50.

• These patients should not be managed with excessive volume resuscitation but rather with vasopressors to restore alpha-adrenergic peripheral vasomotor tone.

• Central venous pressure monitoring or preferably pulmonary artery catheterization can guide the use of intravenous fluids and vasopressor therapy, with a goal of attaining a pulmonary artery wedge pressure of 12 to 14 mm Hg.

SYSTEMIC MONITORING: TEMPERATURE

The goal of temperature monitoring • Temperature monitoring is also important in the neuro- ICU,

since hypothermia can depress neurologic function to the point of obtundation or coma.

• Conversely, fever, by increasing metabolic requirements, may exacerbate secondary injury.

• Core temperature should be kept lower than 38.0°C, using medications (e.g., acetaminophen, paracetamol, diclofenac) and external or intravascular cooling.

• Hypothermia may be due to adrenal or pituitary insufficiency, hypothalamic disorders.

• The possible benefits of hypothermia should be carefully balanced against potential risks (coagulation disorders, electrolyte shifts, fluid overload).

Brain specific monitoring

• Brain specific monitoring, including * ICP monitoring * cerebral blood flow (CBF) * Cerebral oxygenation (using either a

jugular venous bulb catheter or an oxygen sensitive electrode)

* Electroencephalographic (EEG) monitoring can be helpful in postoperative patients in the neuro-ICU.

Brain specific monitoring

• Monitoring of ICP is indicated in * Trauma patients with severe brain injury (GCS score < 8), *Abnormalities on the initial CT scan *further in patients with a normal admission CT scan if two or more of

the following features are present: Age greater than 40 years, Unilateral or bilateral motor posturing, Systolic blood pressure less than 90 mm Hg.

• Routine ICP monitoring is not generally indicated in patients with mild or moderate head injury but may be considered

• When other severe extracranial injuries are present,• Necessitating anesthesia for surgery, • When the initial CT scan shows traumatic lesions with space-occupying

effects.

• ICP monitoring is further indicated in poor grade patients with subarachnoid aneurysmal hemorrhage.

CEREBRAL BLOOD FLOW ANDOXYGENATION

• Intermittent measurements of CBF can be obtained with stable Xenon CT scanning or positron emission tomography studies. Transcranial Doppler echography provides a noninvasive assessment of blood flow velocity through the basal cerebral arteries.

• Global cerebral oxygenation can be assessed using jugular oximetry.

• A decrease in jugular venous saturation of oxygen (Sjvo,) indicates that the brain is extracting more oxygen, suggesting that the J oxygen supply is not adequate for metabolic demands.

• Interpretation of results of jugular oximetry require that systemic

• information, • such as hemoglobin concentration and arterial saturation,

and intracranial data, such as CPP

ELECTRICAL MONITORING

• Continuous EEG monitoring has the potential for detecting nonconvulsive status epilepticus in ICU patients.

• The value of this monitoring has been shown most often in the setting of stroke and TBI.

• As primary monitor of brain function, continuous EEG can be used to titrate continuous infusion of sedative agents,

and the technique can further alert the physician to development of focal or global ischemia

SPECIFIC THERAPEUTIC APPROACHES

TREATMENT OF CEREBRAL HERNIATION AND ELEVATED ICP

• According to the concept of the volume pressure curve ,a small reduction in intracranial volume will already significantly decrease raised intracranial pressure and reverse herniation.

Neurology, Mar 2008; 70: 1023 - 1029

TREATMENT OF CEREBRAL HERNIATION AND ELEVATED ICP

• Ventricular cerebrospinal fluid drainage (if access is available)

• Administration of mannitol, 1 g/kg body weight• Rapid sequence intubation with a neuroprotective

strategy****Lumbar cerebrospinal fluid drainage should

never attempted, as this may increase herniation.• Emergency head CT scan should be performed to

detect the cause of raised ICP and permit targeted treatment,

The main intracranial causes of raised postoperative ICP are:• Mass lesions (hematoma)• Edema (vasogenic, cytotoxic, osmotic, hydrostatic)• Increased cerebral blood volume (vasodilation)• Disturbance of cerebrospinal fluid flow (hydrocephalus, benign intracranial hypertension)

REMEDIABLE EXTRACRANIAL CAUSES

OF INTRACRANIAL HYPERTENSION• Calibration errors• Airway obstruction (kinked endotracheal tube,

tongue, sputum retention, pneumothorax)• Hypoxia (FIO2 ,lung disease/collapse)• Hypercapnia (hypoventilation)• Hypertension (pain, sedation, coughing/straining)• Hypotension (hypovolemia, sedation, cardiac)• Posture (Trendelenburg position, neck rotation)• Hyperpyrexia• Seizures• Hypo-osmolality (sodium, protein)

Conservative therapy of raised ICP

• Sedation, analgesia, and mild to moderate hyperventilation

(Paco2 [30-40 mm Hg])• Osmotic therapy: preferably mannitol given

repeatedly in bolus infusions (dose: 0.25-0.5 glkg body weight, or as indicated by monitoring).

Serum osmolarity should be maintained at less than 315 mOsm/L. If osmotherapy has insufficient effect, furosemide (Lasix) can also be administered.

• Cerebrospinal fluid drainage• Volume expansion and inotropes or

vasopressors when arterial blood pressure is insufficient to maintain CPP and CBF in a normovolemic patient

• More intensive hyperventilation which should be used only with monitoring

of cerebral oxygenation to detect cerebral ischemia.

• Administration of barbiturates• Mild or moderate hypothermia• Decompressive

surgery(lobectomy)

If these methods fail, If these methods fail, second tier therapies for second tier therapies for

raised ICPraised ICP

HEMODYNAMIC AND CEREBRAL PERFUSION

MANAGEMENT

• Neurogenic Pulmonary Edema• Generally, this complication appears in the

initial 4 hours after the neurologic event and is more common in women than in men, possibly related to the preponderance of cases in patients with subarachnoid hemorrhage

• Mechanism Central sympathetic discharge with

pulmonary venoconstriction,

Neurogenic Pulmonary Edema

Treatment• Therapeutic measures are mostly supportive. • Supplemental oxygen is uniformly required and

endotracheal intubation with mechanical ventilation and the application of positive end-expiratory pressure (PEEP) has been reported in about

75% of patients VASOPRESSORS COMMONLY USED IN THE NEONATAL INTENSIVE

CARE UNIT

Neuroprotection

• The original concept of neuroprotection depended on the initiation of treatment before the onset of an event leading to brain damage.

NeuroprotectionMAIN APPROACHES IN

NEUROPROTECTION

STRATEGIES AIMED AT IMPROVINGMETABOLISM AND

MICROENVIRONMENT

THAM tris(hydroxymethyl)amino-methane

Is a biologically inert amino alcohol that buffers carbon dioxide and acids in vitro and in vivo

Mannitol Is widely used in neurosurgery to treat raised ICP

and to decrease brain bulk during intracranial operations and to treat cerebral ischemia.

STRATEGIESAIMED AT IMPROVINGMETABOLISM AND

MICROENVIRONMENTMannitol is considered to exert beneficial effects by two mechanisms:

• 1. An immediate plasma expanding effect, reducing hematocrit and blood viscosity and consequently increasing CBF and cerebral oxygen delivery.

• 2. An osmotic effect, which is delayed for 15 to 30 minutes, while gradients are established between plasma and cells.

• Mannitol can be given in acute emergency situations such as cerebral herniation or as part of a conservative approach to treatment of raised ICP.

• Mannitol is thought to be more effective when given in small, frequent doses rather than by continuous infusion.

• Given in high doses, mannitol may induce hypernatremia, decrease hematocrit, and increase osmolarity. • A serious potential side effect is acute renal failure, which can occur if

serum osmolarity increases above 320 mmol/L.

PLURIPOTENT AGENTS AFFECTING

VARIOUS MECHANISMS• Corticosteroids are widely used within neurosurgery

to treat edema associated with brain tumors and to

prevent brain edema associated with operative procedures.

The presumed mechanisms of action include • Reduction of vascular permeability• Reduction of cerebrospinal fluid production,• Attenuation of free radical production, inhibition of lipid peroxidation, reversal of intracellular calcium

accumulation, and an anti-inflammatory effect.

PLURIPOTENT AGENTS AFFECTING

VARIOUS MECHANISMS• Barbiturates are commonly used as second tier

therapy for the treatment of raised ICP refractory to other

treatment modalities. • The main mechanisms by which barbiturates are 1- The most important effects may relate to the coupling

of CBF to regional metabolic demands, resulting in a decrease in CBF and related cerebral blood volume as a result of decreased metabolic requirements.

2-Other possibilities include scavenging of oxygen free radicals and stabilization of cell membranes.

Barbiturates• The main complication of the use of barbiturates

is • Arterial hypotension, which occurs in up to 58% of

patients.• The decline in blood pressure may be greater than the

reduction in ICP, risking a decrease in CPP, especially in patients with hypovolemia or Cardiac disease.

• Other complications include hypoglycemia, hyper natremia, an increased risk of

infection, liver and renal dysfunction, and cardiac failure

PLURIPOTENT AGENTS AFFECTINGVARIOUS MECHANISMS

• Dexanabinol, erythropoietin, and magnesium are agents with neuroprotective potential currently undergoing further clinical evaluation.

STRATEGIES PROMOTING CELL SURVIVAL AND REGENERATION

• Strategies to promote cell survival and regeneration include cellular replacement, gene therapy, and administration of trophic factors.

• These futuristic approaches are aimed at promoting regeneration and neuroplasticity and may ultimately lead to improved functional recovery

Questions?

Thank you for attention !