Oxygenation Monitoring Flashcards
(25 cards)
Arterial Content
17-20 mlO2/dL
Venous content
12-15 mL O2/dL
A-v content difference
4-6 mLO2/dL
Normal Oxygenation Delivery
950-1150mL O2/min
Index 550-650 mLO2/min/m^2
Normal Oxygenation consumption
200-250 mLO2/min
120-160 mLO2/min/m^2
Normal Oxygen reserve
700-800 mLO2/min
450 mLO2/min/m^2
Shivering
50-100% increase in consumption
Sepsis
50-100% increase in consumption
Ischemic hypoxia
Low blood flow caused by:
Obstruction of Vessels
Coronary/cerebral thrombosis or spasms
Peripheral vascular disease
Hypoxemic hypoxia
Inadequate transfer of oxygen from lungs to hemoglobin
Causes:
Hypoxemia pO2 <60mmHg
Carbon monoxide poisoning
Methemoglobin (Fe 2+ to Fe 3+)
Anemic hypoxia
Lack of hemoglobin
Hemorrhage
Nutritional deficiencies
Hematopoietic problems
Dilution
Toxic hypoxia
Inability of cells to uptake oxygen
Causes:
Sepsis
Cyanide toxicity
Ethanol toxicity
Excessive tissue requirements
Oxygen demand higher than the system can supply
Causes:
Hypermetabolism Systemic inflammatory response syndrome Sepsis Delirium Tremens(alcohol withdrawals) Status seizures Thyroid storm Extreme fevers Malignant hyperthermia
Impaired Oxygen unloading
Capillary level causes:
Alkalemia
Hypocarbia
Large dose of prbc
Bohr shift left
Increase oxygen demand
- patient conditions
- medication
Sympathetic agonist
-procedure
Decrease oxygen consumption
-hypothermia 7 degree rule 50% decrease -morphine -anesthesia -assist/control ventilation -neuromuscular blocking agents
Compensation mechanism for impaired tissue Oxygenation
- Increase co
- Take from venous reserve 75-32%
- Polycythemia (long)
Monitoring oxygen transport
- Arterial and mixed venous sample via lab
- Point of care blood has
- Non invasive pulse oximetry
- Invasive mixed venous saturation
- Continuous indwelling arterial blood gas
- Transcutaneous measurement of local tissue saturation
Spo2 ranges
96-99% normal
85-90% mild tissue hypoxia
75-85% significant tissue hypoxia
Morbid neurological outcomes type 1
- Cerebral death
- non fatal stroke
- new tia
Greater than 70 4-9% chance
Aortic artherosclerosis
History of neurological events 15%
Carotid stenosis
# of gme
Morbid neurological outcomes type 2
New intellectual deterioration
New seizures post op
Predictors:
Low co or hypotension Gme Atrial arrhythmias Systolic hypertension Diabetes Pulmonary disease Alcoholism
Affecting blood Oxygenation
-Delivery Increase map Increase co2 -increase flow via ci Increase hematocrit -adjust head position
- consumption
- increase anesthetics
- decrease temperature
EEG
Superficial electrical monitoring of brain
Voltage difference between electrodes
Synaptic activity of post synaptic potentials
10-20 electrodes
Alpha-relaxed and awake
Beta-alert and awake
Theta-child infant sleeping
Delta- coma deep sleep, deep anesthesia, cerebral ischemia(BAD)
Used for epilepsy!
Need tech to read!
Bispectral index
Processed eeg info to a number and graph
Every 10-15 sec
How?
Reads and calculates
- EEG
- High frequency power spectrum 14-30
- Low frequency bispectrum 1-2
- Suppression of eeg near and total
Number and graph given
1-100 scale. 100 awake
40-60 good anesthesia
Benefit Less anesthetic Decrease awareness Good recovery time Patient satisfaction
Disadvantage
Trending only
Can only treat when on bypass
Monitor screen
