Final Exam Flashcards
What does the left brain reflect?
Logical Sequential Rational Analytical Objective Look at parts
What does the right brain reflect?
Random Intuitive Holistic Synthesizing Subjective Looks at wholes
Frontal Lobe used in…
Word Production Problem Solving Planning Behavioral Control Emotion
Temporal Lobe used in…
Memory
Emotion
Word Understanding
Occipital Lobe used in….
vision
Hypoxia
Inadequate oxygen in body tissue
Ischemia
inadequate blood supply in body tissue
Seizures
sudden attack of an illness or condition, synonyms: attack, fit, spasm, convulsion
Hypoglycemia
the medical condition of having an unusually low level of sugar in the blood (maybe more with kids)
Hyperglycemia
the medical condition of having an unusually high level of sugar in the blood (maybe more with adults)
Neurological Injury
Results from the combination of a patient chronically at risk with a variety of surgically related insults or stresses for which the vascular system is unable to compensate
What are the two types of morbid neurological outcomes?
Type I
Type II
Type I: Morbid Neurological Outcome
Cerebral Death
Non-fatal Strokes
New TIA’s
Type II: Morbid Neurological Outcome
New intellectual deterioration
New seizures upon discharge
Type I Predictors
Advanced Age (predispose to stroke) 70: 4 to 9% risk
Aortic Atherosclerosis
Hx of prior neurologic events- 15%
Carotid Stenosis
Type II Predictors
Low cardiac output states Atrial arrhythmias Systolic Hypertension Diabetes Pulmonary Disease Excessive Alcoholism
What is the prevalence of neurological impairment?
6.1 %
What are some examples of neurological impairment?
Stroke, stupor, coma, deterioration in intellectual function, memory deficit or seizures
What is the prevalence of Post-Op Delirium?
10-60% (depends on age and type of surgery)
What is the LOS of patients with Post-Op Delirium?
These patients have LOS of 20-25 days vs. 10 days for patients with no adverse outcomes
Incidence of Transient Neurologic Dysfunction
7-44%
Incidence of Permanent Complications of neurologic dysfunction
1.6 to 23%
What type of vent placement reduces neurological risk?
RSPV (LA to MV to LV); direct
What part of cardiac surgery has the highest neurological risk?
Short filling of beating heart after XC
Filling again after taking out vent
Surgical Technique addressing Atheroembolism
Epiaortic ultrasound
Single Cross Clamp
No touch techniques
Paying attention
How to perfusionists contribute to neurological dysfunction?
Hypoperfusion
Inflammation
Focal (Embolism)
Global (Complete/Incomplete)
Types of Embolism
Air Plaque Microemboli LV thrombus Fat Debris
Global Examples (Complete and Incomplete)
Complete: cardiac arrest, DHCA
Incomplete: hypotension, inadequate CPB flow
3 Examples of Inflammation
Ischemia Reperfusion Injury
Vascular Integrity
Exposure to Blood
Ischemia Reperfusion Injury
Potent triggers for: activation of leukocyte, leukocyte-endothelial or leukocyte endothelial platelet binding
Vascular Integrity
Foreign Surface
Capillary Plugging
Liberation of free radicals
Exposure to Blood
Activates platelets, monocytes and neutrophils
Factors Affecting Blood Oxygenation
Tailoring Oxygen Delivery
Tailoring Oxygen Consumption
How do you tailor oxygen delivery?
MAP CO2 CI and Pump Flow Hematocrit Mechanical Issues
How do you tailor oxygen consumption?
Anesthetic Agent and Depth
Temperature
What could you do if you want to cool a kid quickly?
Increase CO2. CO2 is huge in changing co2 metabolic delivery
Types of Brain Monitoring
Neurological exam Blood Pressure monitoring EEG- electroencephalogram BIS- Bispectral Index TCD- Transcranial Doppler ICP- Intra-cranial pressure monitoring SjVO2- Saturation of Jugular Venous Oxygen SvO2- Saturation of Venous O2 (global) rSO2-Regional Saturation of oxygen
rSO2
Regional Saturation of Oxygen
What tools can we use to help prevent brain injury?
EEG BIS Monitoring (Bispectral Index) INVOS Somanetics Cerebral Oximetry/Invivo Optical Spectroscopy
What is an EEG?
Recording from scalp of electrical activity in underlying cerebral cortex
Signal by amplifying voltage differences between pairs of electrodes (each pair constitutes a lead attached to the scalp)
Reflects correlated synaptic activity caused by post-synaptic potentials of cortical neurons
Each lead covers a surface area of 2.5 cm
Number of EEG Electrodes
21 International 10-20 electrodes are standard
OR: 2-4 lead monitoring (placed over the cerebral artery)
What hemisphere are odd numbers? (EEG)
1,3,5,7
Left Hemisphere
What hemisphere are even numbers? (EEG)
2,4,6,8
Right hemisphere
What percent of the population show abnormalities due to old injuries?
15%
How are EEG signals defined?
Frequencies
What do alpha and beta activity indicate
patient awake
What do theta and delta activity indicate
patinet asleep
Alpha Wave
8-13 Hz
Medium amplitude
Predominant location: Occiput
Relaxed, awake
Beta Wave
13-30 Hz
Low predominant amplitude
predominant location: frontal
Alert, awake
Theta Wave
4-8 Hz
High predominant amplitude
predominant location: diffuse
Sleeping infant, child
Delta Wave
0-4 Hz
High predominant amplitude
Predominant location: diffuse
Metabolic coma, cerebral ischemia, normal deep sleep, deep anesthesia
Main Reason for using EEGs Clinically
Epilepsy
Brain TUmors
Stroke
Focal Brain disorders
Secondary Reason for using EEGs Clinically
Diagnosis of coma
Encephalopathies
Brain death
EEGs in monitoring depth of perfusion
indirect indicator of cerebral perfusion in carotid endarterectomy
Disadvantages of the EEG in the OR
Analysis is complex distract anesthesia from patient care Electrode impedances Electrical devises in OR Electrical activity in skeletal and cardiac myofibrils (pt moving or shivering) Electromechanical devices (H/L machine)
What voltages does EEG use?
50-100 micro volts (low voltages)
Types of Electrode Impedances
Equal- interference eliminated
Different- appear as artifact
Types of Electrical devices in the OR
Pacemakers
ECG
Electrocaudary units
Increase Frequency associated with:
Hyperoxia Hypercarbia: mild Hypoxia: initial Seizure Barbiturates: small dose Diazepam: ambulatory dose N2O: 30-70% Inhalation Agents < MAC Ketamine
Decreased Frequency, increased amplitude associate with:
Hypoxia: mild Hypocarbia: moderate to extreme Hypothermia Barbiturates: moderate dose Etomidate Narcotics Inhalation agents > 1 MAC
Decreased frequency, decreased amplitude associated with:
Hypoxia: marked
Hypercarbia: severe
Barbiturates: large dose
Electrical silence associated with:
Brain death Hypoxia: severe Hypothermia: profound Barbiturates: coma dose Isoflurane:2 MAC
Bispectral Index (BIS)
- Processed EEG information as a measure of sedative effects of anesthesia meds
- Monitor was approved for use in 1996
- Information displayed every 10-15 seconds
- Most validated measure of consciousness available
- Graphical trend and numerical value
- Non-invasive, continuous, direct and real time
- Allows anesthesia the ability to access the complicated EEG information during the case
- During the signal analysis, multiple characteristics from the EEG are determined and converted to an algorithm
- Uses easy numbering system to identify depth of anesthesia
What does BIS assess?
Relationships among signal components and captures synchronization within signals like the EEG. THen it converts it to a digital number for easy interpretation
The BIS Index
The index is a number between 1 and 100
Correlates to important clinical endpoints and EEG states during anesthesia induction
100 is a fully awake patient
What does a BIS value of 100 mean?
Awake
Responds to normal voice
What does BIS value of 80 mean?
Light/Moderate Sedation
May respond to loud commands or mild prodding/shaking
What does BIS value of 60 mean?
General Anesthesia
Low probability of explicit recall
Unresponsive to verbal stimulus
What does BIS Value of 40 mean?
Deep Hypnotic State
What does BIS value of 20 mean?
Burst Suppression
What does BIS value of 10 mean?
Flat Line EEG
Significant correlation seen between decreasing brain metabolic rate (BMR) and increasing __________.
Anesthesia Effect
Target BIS Values
Tailored to each individual
Target BIS Value using opoid anesthesia
40 to 60
Target BIS Value using opoid anesthesia with supplementation with volatile gas on pump
Normally 25 to 35
Target to titrate to 45-55
Benefits of BIS?
Reduction in primary anesthetic use
Decrease incidence of intraoperative awareness and recall
Reduction in emergence and recovery time
Improved patient satisfaction
Disadvantages of BIS
It is a trending device
We can’t be responsible to treat the level of sedation
Often monitor only faces anesthesia
Two types of Cerebral Oximetry
NIRS (near infra red spectroscopy)
INVOS (invivo optical spectroscopy)
Transcranial Cerebral Oximetry
Non-invasive technique monitoring changes in cerebral oxygen metabolism, which presents additive information when the conventional key variables (as peripheral oxygenation and/or systemic hemodynamics) would not be predictive
Benefits of INVOS
Non-invasive, continuous, direct, real time
Site specific (regional) measure vs systemic; often signals earlier warning of reversible ischemia
Detect and correct oxygenation issues that can lead to complications and poor outcomes
Immediately reflects pt reactions
Not pulse, pressure, or temp dependent
Monitor vascular beds
Identifies patient unique rSO2 baselines for customized care
Enhances clinical assessment and decision making
Objective data vs subjective assessment
MOMM
Major Organ Morbidity or Mortality
What is the MOMM value?
13.4%
What is the MOMM with INVOS?
3%
MOMM is a cumulative score of:
Death within 30 days Permanent stroke >48 hours ventilation Mediastinitis/deep sternal infection Renal failure requiring dialysis Re-operation
Prevalence of Cognitive Decline
24-53%
Prevalence of Prolonged Ventilation
5.96%
What detects O2 supply issues associated with inflow obstructions?
Cerebral rSO2
What are some causes of inflow issues?
Head Position
Heart Position
Arterial Obstruction (Carotid Disease, clamp, hand)
Sponge (cannula malposition)
