Clinical Monitoring Flashcards
(29 cards)
EEG recording produced by
Synchronous depolarization of cell bodies and dendrites as chemical activity is converted to electrical activity
EEG pattern for anesthesia (general and deep)
General: Theta, slower, higher amplitude
Deep: Delta, wider, loopy sleep waves
General anesthesia produces _____ changes on EEG
Dose-dependent
Most common patient perceptions of awareness under anesthesia (5)
- Sounds and conversation (89-100%)
- Sensation of paralysis (85%)
- Anxiety and panic
- Helplessness and powerlessness
- Pain (39%)
Least common patient perceptions of awareness under anesthesia (3)
- Visual perceptions
- Intubation
- Feeling operation without pain
BIS number ranges (normal, general anesthesia, values more likely to have recall)
- Range from 0-100
- General anesthesia: 40-60
- More likely to have recall: >70
Anesthetic technique effect on SSEPs, how to change your anesthetic when they’re used
- IV agents have less effect than inhaled agents
- Propofol/narcotic gtt, no paralysis
- 0.5-1 MAC inhaled agent if cannot do TIVA
Normal ICP in adults
5-15 mmHg, lower in infants/children
MAP calculation
SBP + 2xDBP / 3
Upper arm BP vs down arm
Upper arm=10mmHg lower than down arm
Calf/ankle BP vs arm
Calf/ankle approximately 5mmHg lower than arm
Normal PA pressure
15-30/4-12
Normal PA Wedge pressure
4-12
PA catheter should reside where?
West Zone III of lung
- Bulk of pulmonary blood flow
- Direct communication between right heart and pulmonary pressures and left intraventricular pressures
Mixed venous O2 saturation (SvO2) measures (and normal value)
- Percentage of SaO2 after tissue extraction
- Reflects overall tissue utilization of O2, tissue perfusion, CO
- Alteration in SaO2 will cause alteration in SvO2
- Normal value 5-77%
Oxyhemoglobin dissociation curve
Relationship between plasma O2 and Hgb saturation
-Reflects changing affinity of O2 to Hgb
Right shift of oxyhgb dissociation curve
Decreased affinity so O2 is released to the tissues
-Caused by hypercapnia, fever, acidosis, elevated 2,3DPG
Left shift of oxyhgb dissociation curve
Increased affinity of O2 to Hgb = higher saturation for given PaO2
-Caused by hypocapnia, hypothermia, alkalosis, decreased 2,3DPG
SpO2 50%=PaO2 ____
SpO2 60%
SpO2 90%
50% = PaO2 27 mmHg 60% = PaO2 30 mmHg 90% = PaO2 60 mmHg
End Tidal CO2 Monitoring
Estimates PaCO2 and evaluates ventilation and dead space
Possible causes for increasing baseline on ETCO2
- Defective exhalation valve
- Rebreathing of previously exhaled CO2
- Exhausted CO2 absorber
Possible causes for gradual increase in ETCO2
- Hypoventilation
- Increased metabolism (fever, pain, shivering)
- Partial airway obstruction
- Absorption of CO2 from exogenous source (Lap surg)
Possible causes of suddenly elevated ETCO2
- Tourniquet release
- Bicarb administration
- Reperfusion during vascular grafting
- Malignant hyperthermia
Possible causes for decreasing ETCO2
- Cardiopulmonary arrest
- Pulmonary embolism
- Sudden hypotension, massive blood loss
- Cardiopulmonary bypass
