Monitoring Flashcards
AANA has 5 Standards for Anesthesia Monitoring
all 5 are needed for general
Temp & NMB maybe not for non-general
BP checked Q____min regardless of anesthetic
5
Temp Q
15 min
NM monitoring Q
15 min
most important monitor
Vigilance
⭐️
Monitoring FiO2 (Oxygen Sensor)
oxygen sensor is distal to the CG outlet
as close to pt as possible
determine the concentration of oxygen moving to pt
⭐️
only monitor that can detect a hypoxic mixture of gases
Oxygen Sensor
If the machine does not have a working O2 sensor…
get a new machine
do not start the case without one
All analyzers must have
low-level alarms, which are active while the machine is on
T/F
The Low O2 alarm can be temporarily silenced
False
Required at all times when the anesthesia machine is in use
Oxygen Sensor
polarographic (Clark electrode) & galvanic (fuel cell) are used to measure
Oxygen
T/F
Oxygen is diamagnetic
false
O2 = paramag
other gases = diamag
Oxygen + magnetic field
O2 molecules are attracted & agitated
Oxygen Sensor: Paramagnetic
pressure difference is ____ to O2 partial pressure
proportional
Why is O2 a magnetic gas?
2 unpaired electrons
When did Pulse Ox become a standard of care
‘86
Pulse Oximetry (SPO2)
-Pulse rate
-Estimate Oxygen (SaO2) saturation of Hgb
-time-delayed reading
Pulse Oximetry (SPO2) estimates ___.
Oxygen (SaO2)
saturation of Hgb
measures light absorbance
Spectrophotometry
solute concentrations measured by light transmitted through a solution
Lambert-Beer Law
3 assumptions made for programming all pulseox devices:
-only oxyhemoglobin & reduced Hgb absorb light
-pulsations are d/t pulsatile arterial flow
-empirical experimental oxygen dissociation calibration curve for all humans
An LVAD pt’s SpO2 will look like…
little oscillations
typically no pulse ox b/c they have no pulsatile flow
rely more on etCO2 and skin color
⭐️
Pulse Oximeter (SpO2)
2 wavelengths of light
Red light: 660 nm (unoxygenated Hgb)
Infrared light: 940 nm (oxygenated Hgb)
Pulse Oximeter (SpO2)
algorithm
compares how 660 nm & 940 nm wavelengths are absorbed by deoxyhemoglobin and oxyhemoglobin, and calculates the SpO2 value
using oxyhgb dissoc. curve
⭐️
T/F
A high SpO2 is a sign that the tissues are utilization O2 properly.
False
DOES NOT guarantee delivery of or utilization of O2 by the tissues
Can SpO2 indicate good ventilation?
No
apnea after preoxygenating with 100% FiO2 prior to induction = ___ min before SpO2 drops
6-8 min
(Exam 1 material: at least 8 mins; 10 min if healthy)
IV Dyes that mess w/ SpO2 reading
Methylene Blue, Indigo Carmine, Indocyanine Green(ICG)
Will give us false high SaO2
Carboxy & methemo hgb
Methylene blue will give us a SaO2 reading that is….
much lower than actual
Which binds greater to hgb?
O2
carboxyhgb
carboxyhgb (will push O2 off)
Cerebral Pulse Ox
-Beer–Lambert law
-balance between cerebral oxygen delivery and consumption
NR: 60-75%
⭐️
Pulse ox uses which law?
Beer Lambert
🔴
Cerebral Pulse Ox
Changes greater than __% indicate potential neurological events due to decreased cerebral oxygenation
25
Cerebral Pulse Ox
We want to see ___ between the two values
closeness
not equal
Best to detect Ischemia or Infarction
Leads II or V5
arrhythmias & inferior wall ischemia
Lead II
anterior/lateral wall ischemia
V5
____ Lead monitor both II & V5 simultaneously
5 Lead
EKG leads contain
Silver Chloride
Which mode for:
decreasing artifact?
diagnosing ischemia?
Filtering mode
Diagnostic mode
Lead V5
location
5th intercostal space at anterior axillary line
True V5 only possible with
5 Lead
can do modified V5 with 3 lead
T/F
Gases/volatiles
The % we give to the pt will be higher than the expired %.
True
some is always going to be absorbed
T/F
The inspired % we give to the pt reflects how much is going into the brain.
False
the expired % reflects this
IR Gas Analyzer is located…
on inspi & exp limbs
IR Gas Analyzer detects….
CO2, N2O & potent volatile anesthetics simultaneously
using unique light absorption of the gases
Why is an appropriate level of - pressure matter for patient safety?
Negative pressure + emerging pt biting on ETT –> negative pressure pulmonary edema
Sub-atmospheric/Negative Pressure Alarm
- Neg pressure/reverse gas flow in circuit
Negative pressure can cause…(3)
pulmonary edema
atelectasis
hypoxia
High-Pressure Alarm
causes
peak pressures > 40cm H2O
Mainstem intubation
APL valve closed with high gas flows
Continuous Pressure Alarm
obstruction or malfunctioning expiratory valve
ie: APL closed w/ gas flow & ballooning anesthesia bag
Breathing Circuit Low-Pressure Alarms
PRIMARY cause & other causes
circuit disconnect (70% of the time =Y-piece)
-Faulty/leaking circuit
-Faulty Ventilation Bag
-Leaking from Bellows housing
-Leaking ETT cuff
-Accidental Extubation
-Anesthesia Bag disconnected
-Leaking or disconnected anesthesia machine hose
most serious cause of Low-Pressure Alarm
Leaking ETT cuff
Accidental Extubation
(70% of the time, its a circuit disconnect)
measures the tidal ventilation in anesthesia breathing circuits
flowmeters (not the fresh gas ones)
Flowmeter monitors
Vt in circuit
Real-time flow metering
Ultrasonic
Flapper valves
Mini turbine spirometer
Range: 0-2.5 L/sec
Apnea Detection Alarm
is associated with ___
flowmeters (not the FGF ones)
Apnea Detection Alarm
High-level alert
must always be on
What causes the “upswing” (phase IV/terminal upswing)
-dec. compliance & FRC
preg/obese (decreased FRC) don’t ventil8 well
retained CO2 @ end expiration is pushed out by extra weight
Which part of this graph is the airway deadspace?
Which part of this graph is the alveolar deadspace?
Where can we find the etCO2?
⭐️
Which part of the etCO2 capnog. is not always present?
Phase IV terminal “upswing”
⭐️
alpha angle increase
expiratory outflow obstruction
COPD, bronchospasm, kinked ETT
⭐️
beta angle increase
rebreathing CO2 from faulty inspiratory valve
If etCO2 baseline is elevated….
breathing CO2
change absorbent canister
etCO2 waveform phases
Phase I: INSP Ends
Phase II: EXP (deadspace & Upper Alveoli)
Phase III: EXP (lower lung)
Phase IV terminal “upswing”: (if present)
Phase IV: INSP (fresh gas w/o CO2)
Phase IV should return to ___ with each new breath
0
which one detected CO2?
Right (turns yellow when exposed to CO2)
semi-quantitative device
T/F
Bicarbonate Administration can increase etCO2
True
bicarb breaks down into CO2 & expired
see slight elevation in 10-12 mins
MH will ____ etCO2
increase
(remember: unexplained etCO2 rise is first sign of MH)
Sepsis/fever ____ etCO2
increase
Pulm. Emb ____ etCO2
decreases
A circuit disconnect ___ etCO2
decreases
Hyperventilation will ___ etCO2, but hypoventilation will ___ it.
hypervent= decrease etCO2
hypovent = increase
Low CO will ___ etCO2
decrease
less blood circulation = less CO2 production
A pt will exhibit ___ etCO2 in cardiac arrest
decreased
(good compressions & circulation will produce some etCO2, but very low; so none=dead)
waz gud anesthesia?
nm, just some airway obstruction, hbu?
NIBP
Ejection of pulsatile blood flow from the left ventricle causes pulsatile arterial pressures
Systolic (SBP)
peak pressure from left ventricle during systole
Diastolic (DBP)
lowest arterial pressure during diastole
Pulse Pressure
SBP – DBP
⭐️
Mean Arterial Pressure (MAP)
time - weighted average of arterial pressures during pulse cycle
get your mind out of the gutter….sheeesh
most accurately reflects hemodynamic status
R atrium
phlebostatic axis corresponds to
the right atrium
Accurate SVV fluid responsiveness/fluid challenge
-baseline bolus 200-250 ml
-perform prior to fluid loss
-helps determine what fluid they will respond to
FloTrac
-CO & SVV using arterial waveform (also CI)
-connect to A-line
-use for intraop fluid mgmt
Central Venous Pressure Monitoring (CVP)
Monitors R side of the heart (preload)
&
vascular volume
sits above R atrium
⭐️
Must know a, c, v, x & y
CVP NR
2-6 mmHg
T/F
CVP measures blood volume directly.
False
estimate
Risks of Central Line Placement
Microshock hazard
Pneumothorax
Hemothorax
Thrombus
Thromboembolus
Arterial Puncture
Hematoma
Infection **
Knotting/Breakage of Catheter
Retained Wire
Erosion through vessel/heart
temperature maintained by
balancing heat production (metabolism) & heat loss
T/F
Anesthesia does not affect temp control mechanisms
False
inhibits many of them
types of anesthesia that impair temp control
General & neuraxial
⭐️
Temp MONITORING STANDARD
Q15 min
General Anesthesia Temp decrease (3 phases):
- rapid decrease over 30 min (0.5-1.5 ℃) – redistribution heat from core-to- peripheral tissue
- Slow linear reduction phase of 0.3 ℃ / hr from heat loss exceeding heat production
- Plateau phase (~thermo-regulatory vasoconstriction)
T/F
All volatiles and gases impair thermoregulatory control
False
N2O does not
T/F
Neuraxial anesthesia impairs temp control to the same extent as GA
True
Which monitors both sides of the brain?
sedline
BIS
sedline
BIS monitor
-monitors only 1 side of frontal lobe
-Composite analyzed EEG tracing
BIS ranges
65-85: sedation
40-65: general anesthesia
BIS limiting factors
-Variable Indexes per agent
-Age – brain maturation affects EEG
-Hypothermia (slows brain activity)
-Neurological Impairment (unreliable measuring)
-Interference from medical devices
(same for sedline)
SedLine Monitor
-4 waves of EEG
-both hemispheres of frontal lobe
SedLine Monitor general anesthesia
30-45
AMG vs EMG
AMG: hand, toe, face
EMG: better if tucked
NMB – Quantitative Monitoring
-safe extubation and prevention of residual paralysis
-Uses both:
AMG (acceleromyography) & EMG (electromyography)
