MedSurg2 - Exam 3 Flashcards
Why would you worry if a head injury patient suddenly developed a runny nose?
Because it could be a CSF leak
Why might you see eye bruising in a head trauma patient?
It’s a sign of a skull fracture (to the orbital bone). You’d want to send them to CT/X-ray.
What action would you want to avoid with a patient who has a Basilar fracture?
Insertion of an NG tube
What is Battle’s sign? What is it indicative of?
Bruising behind the ear. Indicative of a skull fracture (basilar fracture?)
What are the two types of Focal Brain injuries?
Contusion and Coup Contrecoup
Describe a contusion. Is it visible or invisible? Microscopic or macroscopic?
A contusion is like a bruise of the brain.
Localized and deep.
Visible on a CT scan
Occurs at a macroscopic level.
Describe a coup contrecoup injury.
It’s a contusion that happens on both front and back (or side to side) of the brain.
What are two Diffuse Brain Injuries?
Concussion and Diffuse Axonal Injury
Describe a concussion. Is it macroscopic or microscopic? Visible or invisible?
A concussion is microscopic damage to the neurons of the brain.
Invisible on imagery
Widespread and diffuse
Disruptive to the physiology rather than the anatomy.
Describe a Diffuse Axonal Injury
Damage to axons that occurs from rotational acceleration. Axons stretch, shear and twist —> swelling and damage to axons —> disruption to neuronal functioning. (Very severe concussion)
Which brain injury is the #1 cause of morbidity? What happens to this patient?
Diffuse Axonal Injury - many patients don’t survive
Electrical signals can’t transmit effectively
Mood disturbances in the long run.
True or False - ALL brain injury types can lead to:
A) disruption in functioning of neurons
B) increased ICP
True to both
3 layers of meninges, from outer to inner
Dura Mater
Arachnoid Mater
Pita Mater
Epidural Hematoma - cause? Problems? Speed of progression?
Typically caused by rupture of the meningeal artery (above the dura).
Arterial bleed = fast with rapid growth (pressure against brain increases quickly).
Can go from lucid to unconscious in a few hours - very fast.
Subdural Hematoma - typical cause? Speed? Different levels?
- Rupture of the bridging vein (between the two hemispheres) in the subdural space
- Venous bleed means it’s slower to develop (s/s will be headaches and confusion)
-Levels:
Acute: takes 24-48h to develop symptoms
Subacute: takes 2-14 days to develop symptoms
Chronic: takes weeks to months to develop symptoms.
What are the components involved in the regulation of ICP?
Cerebrospinal Fluid (CSF)
Cerebral Blood Flow (CBF)
Brain Tissue
Why is it important to keep the head and neck aligned with a patient who’s at risk of increased ICP? What’s the best HOB position?
If there’s an obstruction/kink in the venous outflow, it can create a buildup of ICP, especially in heart failure patients.
Place HOB at 30-45 degrees.
What range of MAP is needed to regulate intracranial pressure effectively?
50-150mmHg
If you have a MAP below 50, what is the effect on the brain tissue?
Cerebral ischemia d/t decreased cerebral blood flow
If you have a MAP over 150, what is the effect on the brain tissue?
Increased ICP due to excess CBF
What is the effect of Acidosis on the vasculature of the brain?
Vasodilation and increased blood flow
What is the effect of Increased CO2 on the vasculature of the brain?
Vasodilation and increased blood flow
What is the effect of hypoxemia on the vasculature of the brain?
Increased blood flow and vasodilation
Why might you hyperventilate a patient with increased ICP?
To blow off excess CO2 (decrease vasodilation in brain)
Why do you have to be concerned about coughing, sneezing, vomiting and ascites in patients with increased ICP? What do we do about this?
Because increases in intra-thoracic and intra-abdominal pressure will increase ICP.
We’ll make sure to provide bowel meds, cough suppressants, anti-emetics, paracentesis (ascites)
If the body can’t compensate for increased ICP, what is the order of decompensated actions?
- Compression of Ventricles (CSF)
- Compression of Blood Vessels
- Decreased blood flow d/t blood vessel compression (tissue death and subsequent ICP increases)
- Swelling and compression of brainstem and respiratory center
- Increase in CO2, vasodilation and more blood flow/brain volume.
When does the risk for herniation occur? What directions can the brain herniate?
When tiny changes in volume leads to big changes in pressure.
Once the brain can’t compensate, brain goes from Poor compensatory reserve to Deranged compensatory reserve.
Brain will herniate Inwards, Outwards or Downwards
What is the most sensitive and earliest indicator of increased ICP?
Behavioral changes / Deteriorating LOC
Ex: restlessness, irritability, decreased attention, slowed speech, lethargy.
What are non-LOC indicators of increased ICP?
Severe Headache, Seizures, N/V Abnormal pupils Altered/irregular breathing pattern Nuchal Rigidity Posturing (decorticate/decerebrate) Cushing’s Triad Halo’s sign Deteriorating GCS
What is Cushing’s Triad?
Severe HTN with widening pulse pressure
Bradycardia
Irregular respirations
What is Halo’s sign?
Tests for CSF leakage in pt’s blood (From head). Dried blood with a “halo” around it.
What are the levels of Glasgow Coma Scale?
Mild: 13-15
Moderate: 9-12
Severe: 3-8
Vegetative: less than 3
Range for normal ICP? At what level does it get treated?
5-15 mmHg
Gets treated at 20mmHg
What is a ventriculostomy (intraventricular catheter)? What are the pros and cons?
-Probe through the skull and into the ventricles (not the brain tissue)
-Measures ventricular pressure
-Allows for therapeutic drainage of CSF
-Allows for delivery of drugs into intraventricular space
Most accurate and Most common.
Cons: HUGE infection risk, risk of bleeding and overdrainage.
What is a fiber optic catheter for? What are the pros and cons?
Catheter that’s placed in the brain tissue (not as deep as a ventriculostomy).
Provides monitoring only. (Second most accurate method) Lower risk of brain infection or bleed.
What is a subarachnoid bolt/screw? Pros/cons?
Screws in just below the arachnoid layer (not the brain tissue).
Easier insertion, faster measurement, lower risk of bleed or infection.
Monitoring only, less accuracy.
Risk of obstruction.
Can be done in the ED.
What is an epidural catheter? Pros/cons?
Placed between the dura and the skull to measure ICP.
Least invasive but least accurate method.
Can be done in the ED.
What are the indications for ICP monitoring?
1) A moderate head injury (9-12 GCS) and some reason the patient can’t be adequately assessed (sedated) OR they have an abnormal CT scan.
2) . A severe head injury (less than 8 GCS) with an abnormal CT
3) A severe head injury (less than 8 GCS) and over 40 y/o OR abnormal posturing.
What two parts of the body do you want to be certain to align with a pt with a head injury?
Neck and Hips
What is the most effective way to administer Mannitol to someone with increased ICP?
IV boluses (not a slow drip)
What electrolyte is important to know about when administering Mannitol?
Sodium - you cannot give mannitol if sodium is over 145
What medication is often given alongside Mannitol?
Lasix
Which IV fluid acts like Mannitol?
Hypertonic Saline (3% NS)
How would you decide whether to give 3% NS or Isotonic fluids (NS, LR) to a head injury patient?
If there is cerebral edema and increased ICP, give 3% NS
If brain ischemia is happening due to decreased volume (or if you need to maintain adequate volume), give NS or LR
In what situation would you give Hypotonic fluids to a patient with a brain injury?
You wouldn’t - EVER
What does the P-wave represent?
Firing of the SA node in the R atrium
What does the flat line after the p-wave (in an ECG) represent?
The contraction of both atria
What does the Q-wave (in an ECG) represent?
The electrical impulse traveling through the bundle of His and the L&R bundle branches (center of the ventricles)
What does the portion from Q to R (in an ECG) represent?
The impulse moving around the outside of the ventricles via the Purkjinke fibers
What does the portion between R and S (in an ECG) represent?
The impulse traveling across and through the ventricles from the Purjinke fibers
What does the flat part after the QRS complex (in an ECG) represent?
Contraction of the left and right ventricles
What does the T-wave represent (in an ECG)
Repolarization of the ventricles
What does the flat part after the T wave (in an ECG) represent?
Resting polarized period before the SA node fires again.
What is the distribution of electrolytes at polarization?
K is inside the cell, Na and C are outside
Depolarization and Repolarization - which is contraction and which is relaxation?
Depolarization is contraction
Repolarization is relaxation
How long should the p-wave last?
This is the time it takes for _____
0.06-0.12s
… firing of the SA note to depolarization & atrial contraction
The PR interval should take ______ to _____ seconds
This is the time it takes for __________
It’s measured from P to _______
0.12-0.20s
…the impulse to spread through the atria, the AV node, the bundle of His and the bundle branches to the Purjinke fibers
The QRS complex should last _____
This represents….
Less than 0.12s
…the time from depolarization of the ventricles to ventricular contraction
The ST segment should last _____
What shape is it?
This represents….
0.12s
It should be flat (isoelectric)
It represents the time between ventricular depolarization and repolarization (refractory period)
The T wave should last _____
It represents….
0.16s
…repolarization of the ventricles
The QT interval should last _______
It’s measured from_____
It represents_____
0.34-0.43s
measured from the start of Q to the end of T
Represents the TOTAL time for depolarization and repolarization of the ventricles.
Which interval (in an ECG) is most likely to be affected by antipsychotics, antiepileptics, antibiotics, etc?
What two medications combined with antibiotics will increase this risk further?
QT interval
Warfarin and Methadone combined with antibiotics increase the risk
A thick fuzzy isoelectric line on an ECG likely has what problem?
Problem with the ground lead
An ECG that is all over the place with shaky artifacts likely has what problem?
Poor electrode contact with the skin (dry them, shave, change electrodes)
How many seconds does each “tab” at the top of an ECG strip represent?
How do you use this to determine heart rate?
3 seconds.
Count the beats in two of them and multiply by ten
What are the dimensions of a large box in an ECG (height in millivolts, length in seconds)?
- 5 millivolt high
0. 2 seconds long
What are the dimensions of a small box in an ECG (height in millivolts, length in seconds)?
- 04s long
0. 1 millivolts high