Transcript Introduction

‫بسم هللا الرحمن الرحیم‬
Principals of Neurocritical Care
Dr.Jarahzadeh
Intensivist
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 postsurgery 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-ICU is associated with reduced
mortality,
when compared with patients admitted to a general ICU.
GOALS OF
POSTOPERATIVE NEUROSURGICAL
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 PROCEDURES
Postoperative 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 selflimiting 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.
INFRATENTORIAL SURGERY
• 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
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, lifethreatening complications early after surgery, and of assessing
neurologic deficits in the following hours to days that follow.
Early Evaluation
A simple check of
consciousness
pupils
Early Evaluation
GLASGOW COMA SCALE
Early Evaluation
Pupillary reactivity and size
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
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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 AND
OXYGENATION
• 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
If these methods fail, second tier
therapies for raised ICP
• 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)
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.
Neuroprotection
MAIN APPROACHES IN NEUROPROTECTION
STRATEGIES AIMED AT IMPROVING
METABOLISM 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 IMPROVING
METABOLISM AND MICROENVIRONMENT
Mannitol 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 AFFECTING
VARIOUS 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 !