Neuromonitoring in Head Trauma Flashcards
Monro–Kellie doctrine states that the sum of the intracranial volumes (CBV, brain, CSF, and other constituents like tumor or hematoma) is constant and that an increase in any one of these must be offset by an equal decrease in another as these volumes are contained in an inelastic and completely closed container (skull). The increased ICP will act to force one or more of the other constituents out through the foramen magnum.
Which of the following will be displaced first?
● A. Cerebrospinal fluid (total volume is 150 mL in brain and spinal canal)
● B. Intravenous blood (total cerebral blood volume is 150 mL)
● C. Arterial blood
● D. Brain parenchyma (total volume is 1,400 mL)
● E. Hematoma or any tumor which is causing the increase in ICP
A. Cerebrospinal fluid (total volume is 150 mL in brain and spinal canal)
A patient after head trauma presents with hypertension, bradycardia, and respiratory irregularity (Cushing’s triad). His intracranial pressure is 25 mmHg (normal intracranial pressure
is 10–15 mmHg in adults or older children, 3–7 mmHg in young children, and 1.5–6 mmHg in term infants), while his cerebral perfusion pressure (CPP) is 60 mmHg (normal CPP is more than 50 mmHg). His plain CT of the brain is normal. What are the risk factors for intracranial hypertension with a normal brain CT?
● A. Age more than 40 years
● B. Systolic blood pressure less than 90 mmHg
● C. Decerebrate posturing on motor examination
● D. Decorticate posturing on motor examination
● E. All of the above
E. All of the above
Following are the indications for ICP monitoring except?
● A. Patients who cannot follow command (patients with GCS less than equal to 8) or patients who do not localize
● B. Patients with multiple systems injuries with altered level of consciousness (especially where therapies for other injuries may have deleterious effects on ICP like high levels of PEEP or the need for large volumes of IV fluids or the need for heavy sedation)
● C. Patients with coagulopathy in which coagulopathy cannot be corrected
● D. Patients with traumatic intracranial mass like EDH, SDH, or depressed skull fracture
● E. Patients with fulminant liver failure with INR more than 1.5 and grade 3 or 4 coma; a subarachnoid bolt is inserted after administration of factor seven 40 μg/kg IV over 1 to 2 minutes
C. Patients with coagulopathy in which coagulopathy cannot be corrected
Complications of ICP monitors include infection, hemorrhage, malfunction or obstruction, and malposition. Identified risk factors for infection include which of the following?
● A. ICH or SDH or IVH or ICP more than 20 mmHg
● B. Neurosurgical operation or irrigation of system
● C. Leakage around IVCs or open skull fractures
● D. Other infections like septicemia or pneumonia OR duration of monitoring more than 5 days
● E. All of the above
E. All of the above
Which of the following is the most accurate method of monitoring ICP?
● A. Intraventricular catheter
● B. Intraparenchymal monitor
● C. Subarachnoid screw (bolt)
● D. Subdural bolt
● E. Epidural bolt
A. Intraventricular catheter
Normal ICP waveforms are due to arterial pulsations and respirations. Arterial systolic blood pressure wave is a 1 to 2 mmHg peak with a small dicrotic notch which is followed by smaller less distinct peaks and it is followed by a peak corresponding to the central venous A wave from the right atrium.
ICP elevations of more than or equal to 50 mmHg for 5 to 20 minutes cause a pathological waveform which is called as what?
● A. Lundberg A waves or plateau waves
● B. Lundberg B waves
● C. Pressure pulses
● D. Lundberg C waves
● E. Traube-Hering waves
A. Lundberg A waves or plateau waves
Indications for jugular venous oxygen monitoring (SjVOs) and brain oxygen tension monitoring (PbtO2) include the need for augmented hyperventilation (pCO2 equal to 20–25 mmHg).
Normal value of jugular venous oxygen saturation is more than 60% (less than 50% suggest ischemia) or arterial jugular venous oxygen content difference of more than 9 mL/dL indicates global cerebral ischemia while its value less than 4 mL/dL indicate
cerebral hyperemia. Normal value for brain oxygen content is more than 25 mmHg while values less than 15 mmHg demonstrates ischemia and increases the likelihood of death. What is
the management suggestion for brain tissue oxygen content value less than 15 to 20 mmHg?
● A. Cerebral blood flow study should be done to determine generalizability of brain oxygen content monitor reading
● B. Tier one includes keeping body temperature less than 37.5°C while increasing CPP to more than 60 mmHg
● C. Tier two includes increasing FiO2 to 60%, increasing paCO2 to 45 to 50 mmHg, and transfusion of PRBCs until Hgb is more than 10 g/dL
● D. Tier three is increasing FiO2 to 100%, increasing PEEP and decreasing ICP to less than 10 mmHg by draining CSF, and giving mannitol and sedatives
● E. All of the above
E. All of the above
Normal white matter blood flow is 18 to 25 mL/100 g-mint (values less than 15 may indicate vasospasm or ischemia while values less than 10 may indicate infarction), while normal gray matter blood is 67 to 80 mL/100 g-mint. K value of probe tip less than 4.9 indicates which of the following?
● A. Probe tip is probably out of the brain
● B. Probe tip is probably too deep
● C. Probe tip is in abnormal position
● D. Probe tip damage to some brain tissue
● E. All of the above
A. Probe tip is probably out of the brain
Goal of IC hypertension include keeping ICP less than 22 mmHg and CPP more than 60 to 70 mmHg. What are the general measures which should be utilized routinely for ICP control?
● A. Elevation of head of bed to 30 to 45 degrees, keeping neck straight and avoiding neck constrictions, avoiding arterial hypotension (as hypotension reduces CBF), controlling hypertension (by using nicardipine if not tachycardic and beta
blocker if tachycardic), avoiding hypoxia (PaO2 less than 60 mmHg or O2 set less than 90%), ventilation to normocarbia (PaCO2 35–40 mmHg), light sedation (codeine 30–60 mg IM every 4 hours), plain CT of brain
● B. Heavy sedation (fentanyl 1–2 mL or MSO4 2–4 mg IV every 1 hour), draining 3 to 5 mL CSF if IVC is present, hyperventilation (PaCO2 30–35 mmHg), mannitol 0.25 to 1 g/kg, bolus of 10 to 20 mL of 23.4% of hypertonic saline, augmented hyperventilation (PaCO2 to 25–30 mmHg)
● C. Be sure the patient is sedated and paralyzed, draining of 3 to 5 mL CSF, mannitol 1 g/kg IV bolus, hyperventilate (PaCO2 less than 25 mmHg), pentobarbital 100 mg slow IV or thiopental 2.5 mg/kg IV over 10 minutes
● D. Decompressive craniectomy
● E. All of the above
A. Elevation of head of bed to 30 to 45 degrees, keeping neck straight and avoiding neck constrictions, avoiding arterial hypotension (as hypotension reduces CBF), controlling hypertension (by using nicardipine if not tachycardic and beta
blocker if tachycardic), avoiding hypoxia (PaO2 less than 60 mmHg or O2 set less than 90%), ventilation to normocarbia (PaCO2 35–40 mmHg), light sedation (codeine 30–60 mg IM every 4 hours), plain CT of brain
Longer periods of hyperventilation are needed in patients with documented intracranial hypertension unresponsive to sedation and paralysis and for intracranial hypertension that results from hyperemia. Which of the following are the caveats
of hyperventilation?
● A. It is avoided during the first 5 days of injury if possible
● B. It is not used prophylactically without proper indications
● C. If documented IC HTN is unresponsive to other therapies, hyperventilate PaCO2 only to 30 to 35 mmHg
● D. If PaCO2 of 25 to 30 mmHg is necessary, then monitoring of jugular venous oxygen content or cerebral blood flow should be done
● E. PaCO2 should not be reduced below 25 mmHg
● F. All of the above
F. All of the above
Rapidly developing hyperemia following head injury is due to loss of autoregulation. What is the mortality associated with malignant cerebral edema?
● A. 50%
● B. 70%
● C. 80%
● D. 90%
● E. Almost 100%
E. Almost 100%
Of the following methods for ICP monitoring, which is both diagnostic and offers a benefit in treatment for intracranial hypertension?
● A. Intraventricular
● B. Dural
● C. Subdural
● D. Subarachnoid bolt
● E. Parenchymal
A. Intraventricular
Of the following methods for ICP monitoring, which is the most accurate?
● A. Intraventricular
● B. Dural
● C. Subdural
● D. Subarachnoid bolt
● E. Parenchymal
A. Intraventricular
Which of the following is not a risk factor for intracranial hypertension (IC-HTN) with a normal CT?
● A. Age > 40 years
● B. SBP > 90 mmHg
● C. SBP < 90 mmHg
● D. Decerebrate posturing
● E. Decorticate posturing
B. SBP > 90 mmHg
ICP monitoring can be discontinued how many hours after cessation of ICP therapy?
● A. 6 to 12 hours
● B. 12 to 18 hours
● C. 18 to 24 hours
● D. 24 to 48 hours
● E. 48 to 72 hours
E. 48 to 72 hours
