Intensive care after Neurosurgery
Fink Ch 58
The principle goal of post-operative Neuro ICU is the detection oand treatment of
postoperative complications
The second goal is to prevent secondary insults
Postoperative Complications
Systemic Complications
o Thromboembolic (DVT, PE, MI)
o Infection (Pneumonia, UTI, line sepsis)
o Hypovolemia (Blood Loss)
o Coagulation (Blood Loss, DIC)
o Air Embolism (Sitting Position, Large
cerebral vein opening during OR)
o Pulmonary (atelectasis, pneumothorax)
o Metabolic (hyperglycemia, DI, ↓Na)
o Pressure sores and Decubitus Ulcers
(Intraoperative positioning, cervical
traction, paraplegia)
Neurosurgical Complications
o Postoperative Hematoma (subgaleal,
epidural, subdural, intraparenchymal)
o Brain Edema (edema, vasodilation)
o Cerebral Ischemia (SAH, vasospasm)
o Infection (Meningitis, cerebral abscess)
o Seizures
o Hydrocephalus (obstruction/resorption)
o Tension Pneumocephalus
o CSF Fistula
o Inverse cerebellar herniation
o Cranial nerve lesions
Secondary insults
Event
Hypoxemia
Hypotension
Anemia
Hypocapnia
Hypercapnia
Hyperthermia
Hypothermia
Hyperglycemia
Hypoglycemia
Hyponatremia
Hypernatremia
Main Causes
Hypoventillation
Aspiration/Atelectasis
Pneumonia
Anemia
Hypovolemia
Cardiac failure
Sepsis
Neurogenic shock
Blood loss
Hyperventilation (spontaneous
or induced)
Respiratory depression
Stress response
Infection
Central dysregulation
Exposure
Central dysregulation
Hypothermia, steroids
Inadequate nutrition, pituitary
insufficiency
Hypotonic fluids
Cerebral salt wasting
SAIDH
DI
Osmotic agents (3% NaCl)
Adverse event
Decreased O2 delivery and increased risk of ischemic
damage
Decreased CPP, decreased CBF, increased risk of
ischemia
Decreased O2 delivery, increased risk of ischemia
Cerebral vasoconstriction with risk of ischemic damage
Increased Cerebral Blood Volume, ↑ICP
Metabolic requirements>delivery
Significant coagulaopathy, ↑ infection risk
Acidosis, electrolyte disturbance, ↑ infection risk
Energy depletion, seizures
Increased edema, seizures
Lethargy, coma
PREVENTION AND MANAGEMENT OF NEUROSURGICAL POSTOP COMPLICATIONS
Supratentorial Surgery
1.
2.
3.
4.
5.
Postop subgaleal hematoma
a. 11% of procedures, usually from damage to superficial temporal artery or the temporalis
muscle
b. Minimize by routine post op wound drainage
c. Reoperation is seldom necessary
Intracranial hemorrhage
a. 1% of procedures, intraparenchymal (43-60%), epidural hematomas (28-33%), subdural
(5%)
b. Neurologic deterioration may necessitate reoperation
c. Parenchymal are more common in partial resection of a tumour
post op brain swelling
a. predisposing factors = hypercapnia, arterial hypertension, obstruction of venous drainage
b. if brain swellin goccured during procedure consider deep hematoma and do immedoiate
post op CT
c. if secondary to vasodilation – hyperventilate and sedate
d. if secondary to edema – osmotic agents and mild hyperventilation until settled
Tension Pneumocephalus
a. Rewarming of normally present air post op or continuous air leakage from CSF fistula at
the skull base
b. ↓LOC, ↑ ICP, seizures
c. Usually self limited and do not require reop
Seizures
a. Serious complication – may cause vasodilation, increased CMRO2, and increased edema
b. Prophylactic antiseizure mnedications controversial but at least for high risk patients
i. Cerebrovasular surgery
ii. Cerebral abscess and subdural empyema
iii. Convexity and parafalcial meningiomas
iv. Penetrating brain injury
v. Compound depressed skull fracture
Infratentorial surgery
Essentially the same problems as above
However, given the relatively smaller volume complications happen faster and the close proximity to the
brainstem and cranial nerves can make small issues devastating
There is an increased risk of hydrocephalus due to obstruction at the level of the fourth ventricle
This may lead to increased pressure in the posterior fossa and in rare instances cause upward (inverse)
herniation
Lesions of the cranial nerves can lead to absent gag and aspiration
Some patients develop aseptic meningitis
Infrequently there is a complication know as cerebellar mutism it is transient and its cause is poorly
understood but a vascular cause has been hypothesized
MONITORING
o
ABP monitoring is recommended in all post op patients zeroed at the level of the ICP monitor for
more accurate CPP calculations
o
Temperature monitoring
o
ICP monitoring is indicated in trauma patients if:
1. GCS < 8
2. abnormal admission CT scan
3. normal CT scan with 2 or more of the following
a. age > 40
b. uni or bilateral motor posturing
c. sBP < 90
otherwise up to surgeon and intraoperative findings
Increased ICP and Cerebral herniation
o medical emergency
o Causes (intracranial)
o Mass lesions (hematoma)
o Edema
o Increased cerebral blood volume (vasodilation)
o Disturbance of CSF flow (hydrocephalus)
o Causes (extracranial)
o Airway obstruction
o Hypoxemia
o Hypercapnia
o Hypertension
o Fever
o Seizures
o Hypo-osmolality
o Posture – neck rotation/trndellenberg – impairing venous drainage
o Monroe-Kellie hypothesis
o 3 things in the head – blood, CSF and Brain. If one increases in volume one of the others
must decrease
o
Treatment
o Ventricular CSF drainage - if there is a drain in place
o Hyperventilation
o Mannitol 0.5-1g/kg
o Hypertonic Saline
o Propofol
o Paralysis
o Lasix
o ?elevate the head of the bed (controversial)
o If these fail then
 More aggressive hyperventilation
 Barbiturates
 Mild hypothermia
 Decompressive surgery
HEMODYNAMIC/RESPIRATORY ISSUES
Neurogenic Pulmonary edema
o Reported after many neurosurgical procedures including:
o Brain tumour resection
o Cysts
o Hydrocephalus
o Intracranial hemorrhage
o Brainstem lesions
o Attributable mortality of 9%
o Generally occurs in the first 4 hours after the neurologic event
o More common in women than men
o Mechanism
o Thought to be related to central sympathetic discharge causing massive pulmonary
venoconstriction although reports have shown both high and low protein in the alveolar
fluid
o Most commonly associated with ↑ ICP and therapy is directed at decreasing ICP, otherwise mostly
supportive
o Give O2 and PEEP
o No data on NO
Disturbed Autoregulation
o Increased CPP may increase ICP and cerebral edema