Monitoring - Quiz 2 Flashcards
In the AANA standard of care, what does it say in regards to the alarm sounds in the OR?
When any physiological monitoring device is used, variable pitch and threshold alarms shall be turned on and audible.
Is a pulse ox a standard of care?
YES
Is EtCO2 mandatory?
Yes in the hospital, not mandatory in office based settings
Is an EKG a standard of care?
YES
Is temperature measurement a standard of care?
NO
Is checking twitches a standard of care?
Yes if using neuromuscular blocking agents
Name some things you can see with inspection
Adequacy of oxygenation CO2 high – pt turns red/cherry red lips Fluid requirements Positioning/alignments of body structures IV infiltrations Arms/legs off table Surgeon leaning of pt Blood in suction canaster Edema
What are some things you can monitor with auscultation
Placement of airway devices Heart sounds Blood pressure You can hear the monitor for changes in heart rate and pulse Ox Surgeon “oh shit” Listen to suction Know where you are in the procedure
What are some things you can monitor with palpation?
Quality of pulse
Degree of skeletal relaxation
Locate vascular structures and anatomic structures with line placement
Pulse ox is a reliable monitor that provides early
warning of arterial hypoxia
Despite adequate oxygenation on the pulse ox, what could still be happening?
Hypoventilation, hypercapnia and impending respiratory arrest can occur despite adequate oxygenation
What is something you can do to help flow to improve pulse ox reading?
Nerve block - blocks sympathetic constriction and allows for vasodilation and better blood flow
What are the 2 wavelengths that flow though a pulse ox?
Red light - 660nm - deoxygenated blood absorbs more
Infrared light - 940nm - oxygenated blood absorbs more
What law is the pulse ox based off of?
Beer Lambert law
What are some reasons for inaccurate pulse Ox readings
Hypo perfusion (vasoconstriction, hypothermia, hypotension)
Artifact motion artifact
Methalyne blue and indigo carmen
Anemia
Cautery interference
Abnormal HGB (sickle cell, methemoglobin, carboxyhemoglobin)
methemoglobin has a 1:1 absorption ratio read at 85%, it falsely underestimates SpO2 if sats is
greater than 85%
methemoglobin has a 1:1 absorption ratio read at 85%, it falsely overestimates SpO2 if sats is
less than 85%
How do you treat methemoglobin?
Give methalyne blue - causes HGB to alter back to normal
What will the pulse Ox look like on a pt with carbon monoxide poisoning (carboxyhemoglobin)
will look the same as if pulse ox was reading O2
What can a co-oximetry do?
can differentiate between carboxyhemaglobin, methomoglobin, and oxyhemaglobin
Which dyes can effect the reading of an SpO2 when in circulation?
methalyne blue, indigeno carmen, inocyanine green.
when in circulation, it blocks light and drops pulse ox for a while but will return to normal (bladder surgery/cystoscopy)
A PaO2 of 40,50, 60 equals
Sats of 70, 80, 90
What color nail polish can effect O2 sats
blue, black, green
After placement of artificial airway device, how do you confirm placement?
auscultation, chest excursion, and confirmation of expired carbon dioxide.
Where is the best place to look for retractions?
right above sternum
Condensation in mask does not show adequacy of ventilation, it only show
that air is moving
Does chest movement confirm ventilation?
NO, chest movement does not confirm ventilation. An obstructed pt will still have chest movement.
Failure to intubate is problematic, but failure to recognize misplacement is
catastrophic
What does a pericardial stethoscope provide?
continuous auditory confirmation of ventilation, quality of breath sounds, regularity of heart rate, and quality of heart tones
most often used in peds cases
When using a pericardial stethoscope, what does hearing muffled heart tones mean?
associated with decreased cardiac output
What is a contraindication to esophageal stethoscopes?
Instrumentation of the esophagus should be avoided if there is a history of esophageal varices or strictures, bariatric surgery
In a pericardial stethoscope, where is the bell placed on the patient?
Heavy bell-shaped piece of metal placed over the chest or suprasternal notch
What is a complication of esophageal stethoscopes?
If the stethoscope slides into the trachea vs. the esophagus a gas leak will occur around the endotracheal tube.
EtCo2 provides
information on adequacy of ventilation and confirms placement of endotracheal tube in the respiratory tract.
Is EtCo2 accurate in sedation patients, such as GI lab?
NO, it is accurate in intubated patients
The absence of an EtCo2 waveform could mean
esophageal intubation
circuit disconnect
cardiac arrest
What is the measured difference between an EtCO2 measurement and an arterial CO2
EtCO2 lower by 2-5 torr is normal
> 10 something else going on (shunt??)
Advantages of a mainstream (inline) CO2 detector?
Faster response time
No water trap or pump mechanism
Disadvantage: increase apparatus dead space
Disadvantages of a side stream (diverting) CO2 detector?
Response time slower
requires a water trap
Does NOT increase apparatus dead space
(Always has some suction to pull CO2 to analyzer)
In a CO2 waveform, what is A-B
Exhalation of atomic dead space (no CO2)
In a CO2 waveform, what is B-C
Exhalation of atomic dead space and alveolar gas (measurable CO2)
In a CO2 waveform, what is C-D
Exhalation of alveolar gas (best correlates to V/Q status)
In a CO2 waveform, what is D-E
Inspiration of fresh gas that does not contain CO2 - return to baseline
Where is EtCO2 measured and what is normal range?
measured at point D
Normal is 35-40 mmHg
If the alpha angle is increase, what does that mean?
airflow obstruction (COPD, bronchospasm, kinket ETT, asthma)
If the beta angle is increased, what does that mean?
rebreathing (faulty unidirectional valve or exhausted CO2 absorbant)
Asthma, bronchospasm, COPD, foreign body in upper airway, kinked ETT will have what distinct shape on CO2 waveform?
sharkfin, as pt tries to breath out - creates slow upstroke
Hypoventilation, decreased RR, decreased TV, insufflation can cause what on the CO2 waveform?
increasing EtCO2
If you have malignant hyperthermia, what will you see in the EtCO2
Waveform gets taller and taller (very distant) CO2 will rise very quickly and in a short amount of time.
Decreasing EtCO2
Hyperventilation, increased RR, increased TV, metabolic acidosis, fall in body temp
What will rebreathing CO2 look like?
Staircase step up, not returning back to baseline
What can be some causes of rebreathing CO2
Faulty expiratory valve Inadequate inspiratory flow Partial rebreathing inadequate expiratory time exhausted CO2 absorbant
How does a curare cleft happen
happens when pt is mechanically ventilated and paralytic starte to wear off, diaphrams jumps
What is mass spectrometry
tubing from up to 32 rooms where brought to 1 unit, particles separated by mass, got a reading at a later time
What is monochromatic infrared spectroscopy?
Infrared wavelength passed through at 3.3um, monitor MUST be programed with agent selected
What is polychromatic infrared spectroscopy?
Infrared light beam is passed through at 7-13um. The monitor can automatically identify the inhaled anesthetic agent.
Should the SRNA change from one inhalation agent to another, the monitor can measure the concentrations of both drugs simultaneously.
What we see today**
What is Raman Scatter Spectrometry?
Uses high power argon laser to produce photons
Respirometer/Ventimeter where used on old ventilator machines on the exhalation limb. What did they measure
tidal volume and minute ventilation
When the PIP low pressure sounds alarms, what could that mean?
inspiratory pressure did not achieve predetermined level
Disconnect in circuit
Leak in breathing system
When the PIP high pressure sounds alarms, what could that mean?
positive airway pressure exceeded a predetermined value. Usually set at 40cm H2O pressure.
may indicate low pulmonary compliance.
check for obstruction
How often do you record BP and HR
at least every 5 minutes
ECG reflects electrical activity
in the heart
Is ECG a measure of heart function?
NO, You may have normal ECG complexes on the monitor with no effective cardiac output.
For ST segment monitoring, standardized 1 mV signal change indicates a deflection of ______ on a paper monitor strip.
10 mm
ECGs provide continuous analyzes of ST segments for early detection of
myocardial ischemia
On ECG, the audible beep for each QRS complex should be set loud enough to detect _____ and ______ changes when visual attention is directed to other clinical tasks.
rate and rhythm changes
Normal
PR interval
QRS duration
QT interval
PR interval - .12-.20
QRS interval - .06- .12
QT interval - < or equal to .40
When performing a TE, where does the probe lay and what part of the heart is it looking at?
the transducer lies in the lower esophagus in close direct fluid contact with the posterior of the heart (the images are superb since there is no interference by lung tissue)
From a clinical viewpoint CVP parallels right atrial pressure, which is a major determinant of
RV end diastolic volume
In healthy hearts, right and left ventricular performance is parallel, so left ventricular filling can also be assessed by CVP measurement.
A BP cuff that is too small
overestimates SBP
Cuff pressure to occlude the artery is _______ when cuff is too small
higher
A BP cuff that is too large
underestimates SBP
Cuff pressure to occlude the artery is _______ when cuff is too large
lower
At aortic root,
SBP is
DBP is
PP is
SBP is lowest
DBP is highest
PP is narrowest
At dorsalis pedis
SBP is
DBP is
PP is
SBP is highest
DBP is lowest
PP is widest
Underdamped A line
overestimates SBP
underestimate DBP
map accurate
Overdamped A line
underestimates SBP
Overestimates DBP
map accurate
causes: bubble or clot in tubing, pressure bag low
In CVP, what does A wave represent
Right atrial contraction
In CVP, what does C wave represent
Right ventricle contraction (tricuspid valve bulging into right atrium)
In CVP, what does V wave represent
Passive filling of RA
In CVP, what does X descent represent
Right atrial relaxation
In CVP, what does Y descent represent
Right atrium empties through open TV
Where should CVP be interpreted?
End expiration
If transducer is above zero point, it will_________ CVP. If transducer below zero point, it will ________ CVP
underestimate
Overestimate
Name some examples that decrease SVO2
Stress, pain, thyroid storm, shivering, fever, seizure, decreased PaO2/HGB/CO
Name some examples that increase SVO2
hypothermia, cyanide toxicity (from Na nitroprusside), Sepsis, increased PaO2/HBG/CO, wedged PAC, L to R heart shunt
When does temp need to be continuously monitored?
on all pediatric cases receiving general anesthesia
During general anesthesia the body cannot compensate for hypothermia because anesthetics inhibit
central thermoregulation by interfering with hypothalamic function.
What is the best thing to do in order to prevent heat loss?
STAY ahead, keep them warm from the start
To check a TOF you place it where there is a ______ and ______ near the nerve
nerve and muscle
When checking a TOF on the ulnar nerve, what is stimulated?
adductor pollicis muscle
When checking a TOF on the facial nerve, what is stimulated?
obiqularis oculi muscle
On a nerve stimulator, the red is ______ and the black is _____. The ______ should be placed closer to the heart.
red is positive
Black is negative
red should be closer to heart
The nerve stimulater sends an impulse down the ___________, and __________ is released to produce a stimulus
neuromuscular junction
acetylcholine
Succs is a __________ neuromuscular blocking agent. How does it work?
Depolarizing.
goes to receptor and “sticks” it open so it can’t depolarize again. Will see fascinations.
Vec/rec are __________ neuromuscular blocking agent. How does it work?
Non-depolarizing neuromuscular blocking agents.
Hit receptors and block them– you get paralysis
A single twitch provides
1 twitch at 0.2 msec duration
.1-1 hert
TOF provides
4 twitches 0.2 msec duration at 500 msec apart
2 hertz
Describe Tetany
As long as button is held down, it will deliver continuous stimulation (do it for a period of 5 seconds)
50-100htz
When doing tetany and they can hold the contraction for more than 5 seconds, what does that mean?
there is not enough paralytic
if fades out - paralytic still around
Double Burst stimulation is
2 Burts further apart
.2 msec in duration and 750 ms apart
50htz
possibly more accurate
What is post tetanic facilitation?
Checking a TOF after tetany
When paralyzing a patient, the more receptors blocker, the
more paralyzed the pt
When you get to 70-75% if receptors being blocked,
twitches will still be the same (strong)
When you hit 75% and beyond of receptors being blocked, the twitches
get weaker
Fading means difference between twitch 1 and twitch 4. This ONLY happens with what paralytics?
Non-depolarizing (Roc/Vec)
When 90% of receptors blocked, how many twitches will you get
1
I can get 4 twitches on my TOF (or have 75% of receptors blocked) and the patient may
STILL BE PARALYZED
can have respiratory problems in pacu. Give reversal
If I check a TOF on a pt the I gave Succs (depolarizing) to, how will the twitches look?
They will be the same 1-4 (NO FADING)
Oliguria is defined as
UOP < 0.5 ml/hr
EEGs can provide early evidence of
cerebral ischemia
When monitoring the depth of anesthesia, EEG activity will
decrease in amplitude and frequency while under general anesthesia
What is an evoked potential
is an electrical manifestation of the brain’s response to an external stimulus
electrophysiologists read these
When evoked potentials are used during a surgical procedure, it increases
potential of neurologic injury
How to measure Somatosensory evoked potentials (SSEP)
looking at sensory side of spinal cord – Afferent, start signal at feet and monitor it at the head
(afferent is toward brain)
How to measure Motor evoked potential (MEP)
monitor Efferent, stimulate from head, monitor at periphery
E for exit
What will general anesthesia do to evoked potential?
depress signals
What will propofol do to evokes potentials?
nothing
On a BIS 0 means 20 means 40 means 60 means 80 mean 100 means
0 mean flat line 20 means burst suppression 40 means deep hypnotic sleep 60 mean general anesthesia 80 means light sedation 100 means fully awake
What is the range we try to keep BIS numbers?
40-60
What is cerebral oximetry monitoring?
Provided real time changes in regional oxygenation
Cerebral oximetry measures non pulsatile flow, so what blood is it measuring in the brain?
venous blood
What percent change in baseline would suggest a reduction in cerebral oxygenation?
a change of 25% from baseline
