EXAM 2 Reading 2 (B.Ch26) Flashcards
What the optimal bispectral index range for general anesthesia?
40-60
A BIS score of 100 indicates that the patient is
awake and should respond to normal voice.
BIS score of 1-40
Deep anesthesia
BIS score of 41-60
Desired range of GA
BIS score of 61-90
Light anesthesia
BIS score of 91-100
Awake
Which of the following devices utilizes spectrophotometry to derive the values it produces?
Pulse oximetry
Pulse oximetry utilizes spectrophotometry, which is based on the what law?
Beer-Lambert law
If you pass a light with a constant intensity through tissue, the intensity of the light that passes through it is a
logarithmic function of the hemoglobin saturation.
Which arterial cannulation site provides the easiest access during low cardiac output states?
Femoral
Easy access for low-flow states for arterial cannulation and direct blood pressure monitoring
Femoral artery
Which of the following factors may lead to overestimation of the SaO2 by an SpO2 monitor?
Severe anemia
Severe anemia can result in overestimation of the SaO2, particularly at
low oxygen saturations. Non-hypoxic SaO2 values are typically normal in anemic patients, however.
Prominent venous pulsations and injection of certain dyes such as indigo carmine, lymphazurin, nitrobenzene, indocyamine green, methylene blue, and patent blue can result in
underestimation of the SaO2.
Methemoglobinemia tends to drive the pulse oximetry measurement towards _____ regardless of the actual oxygen saturation.
85%
Methemoglobinemia which can occur due to large doses of (3) what can they cause?
benzocaine, prilocaine or EMLA; skew the results of pulse oximetry.
Methemoglobin absorbs the two frequencies of light used in pulse oximetry in a
1:1 ratio, which corresponds to an oxygen saturation of 85%.
Because methemoglobin skews the result towards 85%, it will
underestimate the oxygen saturation if the true oxygen saturation is greater than 70% and will overestimate the oxygen saturation when the true hemoglobin saturation is less than 70%.
Calculate the mean arterial pressure (MAP) in mmHg for a patient with the following hemodynamics: SBP/DBP: 147/89; HR: 85. Round to the nearest whole number.
108 (Systolic + 2(DBP)]/ 3
A patient has suspected carbon monoxide poisoning. The best method for evaluating oxygen saturation in this case is
laboratory co-oximetry
In carbon monoxide poisoning,
the carbon monoxide molecule binds to hemoglobin, leaving less hemoglobin available to bind with oxygen. The patient can be hypoxic even though the oxygen saturation level is 100%.In this instance, oxygen saturation must be evaluated using a laboratory co-oximeter
The laboratory Co-oximetry uses
uses more wavelengths of light to distinguish between carboxyhemoglobin and oxyhemoglobin.
The bladder of a blood pressure cuff should have a LENGTH that is ___% of the circumference of the arm
80%
The bladder within the blood pressure cuff should have a WIDTH that is
about 40% of the circumference of the extremity
A cuff that is too small can lead to while
overestimation of the blood pressure
Cuffs that are too large can
underestimate the actual pressure.
Represents the initial stage of expiration. Gas sampled during this phase occupies
Phase A-B. anatomic dead space and is normally devoid of C02.
Types of oxygen analyzers commonly used in anesthesia
galvanic cell analyzers. paramagnetic analyzers
polarographic analyzers
The percent of hemoglobin that is saturated with oxygen is directly related to the
oxygen tension in the bloodstream
The percent of hemoglobin that is saturated with oxygen is directly related to the oxygen tension (or partial pressure of oxygen) within the bloodstream. Because of this relationship, it provides a
good way of estimating a patient’s oxygenation status.
2 Non-metabolic causes of increased end-tidal CO2?
Hypoventilation
Rebreathing
Hyperthermia, sepsis, malignant hyperthermia, shivering, and hyperthyroidism are all factors that:
increase the metabolic rate and subsequently, the amount of carbon dioxide produced.
Your anesthesia machine has a removeable oxygen sensor. You know that this device is most likely a _____ sensor
Galvanic
Galvanic analyzers measure the current produced at the
anode of an electrical circuit as oxygen diffuses across a membrane.
Have a sensor capsule that must be replaced regularly.
Galvanic analyzers
The removable oxygen sensors seen on anesthesia machines are most commonl
galvanic sensors.
Which is the most common site for central venous cannulation by anesthesia providers
Right INTERNAL JUGULAR VEIN
Central venous cannulation with the most success rate
right IJ vein
A decrease in the end-tidal carbon dioxide level could be caused by any of the following conditions except
Sepsis
Pulse oximetry uses ___ light and ___ light to evaluate the oxygen saturation.
Read; Near-infrared light
A pulse oximeter uses light of two different wavelengths to distinguish between
deoxygenated hemoglobin and oxygenated hemoglobin.
Pulse ox emits red light with a wavelength of _____and near infrared light with a wavelength of ____
660 nm;940 nm.
What is the preferred site for invasive monitoring of arterial blood pressure
Radial artery
Statement about the BIS monitoring : level of sedation and BIS relationshi
The level of sedation and the BIS score are inversely related
Which factor decreases ETCO2 during anesthesia
Hypothermia
What is the preferred position for a noninvasive blood pressure cuff in an infant with a patent ductus arteriosus
RIGHT ARM
The preferred placement of a noninvasive blood pressure cuff in pediatric patients and why ?
upper extremity because it most closely mirrors cerebral perfusion.
If a patent ductus arteriosus is present, the pressure should be taken in the right arm to provide the most accurate representation of
cerebral perfusion.
The ETCO2 waveform suddenly drops to near zero and the waveform disappears. What are the potential causes you must immediately consider? (select four
a. Malposition of the endotracheal tube
b. Cardiac arrest
c. Obstruction of the sample line
d. Circuit disconnection.
Where is the oxygen analyzer located
INSPIRED LIMB of circuit
Is there a delay in the pulse ox reading?
Yeah about 15-30 seconds
Pulse ox and HR and BP
Plethysmotraphic waveform measurement of HR and crude estimation of BP, DAMPENED WITH HYPOTENSION
The best monitor for determining the adequacy of ventilation
Measurement of Exhaled CO2.
Shape of capnograph provides important information including presence of
Bronchospasm
Sudden loss or decrease ETCO2
Misplaced ETT
Reduction in lung perfusion from PE, anaphylaxis and cardiac arrest.
Cardiac ischemia is best detected by monitoring
Leads II and V5
BP at the very least should be measured
Every 5 minutes.
BP use what method to measure BP
Oscillometric method
Temperature probes preferred during anesthesia
Nasopharyngeal or ESOPHAGEAL TEMPERATURE.
Surrogate marker for adequate perfusion to the rest of the body?
Urine output
Target UO
0.5 ml/kg/hr
NMB most commonly used pattern is the
TOF
EACTH Train consists of
four stimuli applied at 2 Hz.
What happens to TOF height as NMB increases?
With increasing NDNMB height of twitch response decrease, each twitch in the TOF sequence has a smaller height than the one before it.
For NMB to be considered fully reversed, T4/T1 should be
> 0.9
What are potential site for monitoring neuromuscular blockade?
Ulder
Tibilis posterior
Facial nerve
Ulnar nerve NMB monitor which muscle:
Adductor pollicis
Tibialis Posterior nerve NMB monitor which muscle:
Flexor hallucis brevis
Facial nerve NMB monitor which muscle:
Orbicularis occuli
Corrugator supercilii
Where should esophateal probe be placed?
Lower third of esophagus
Where should pressure transducers be placed?
Level with upper border of the heart, 5 cm below the sternal border in a supine patient.
Measurement components of A-line
Systolic BP at the peak of the upstroke, diastolic blood pressure at the nadir, and mean arterial pressure.
Where do you see the dicrotic notch?
After systolic peak, during the down stroke, REPRESENTS the pressure reflection form closure of the aortic valve.
Overdamping of the waveform is caused by
Air bubbles
Blood clots in the catheter’or tubing.
Overdamping and BP estimation
UNDERESTIMATION
Underdamping of the waveform and BP
Overestimation of true systolic pressure.
The ______is the most reliable measurement for most monitoring purposes
MAP.
What are component of the CVP?
Consists 3 peaks (a, c, v)
and 2 descents (x, y)
Atrial contraction waveform component
a-wave
c wave
Isovolumetric ventricular contraction, closure of tricuspid valve
V wave is the
venous filling of the right atrium, tricuspid valve.
y-descent is
Blood flow from the right atrium to right ventricle after tricuspid valve opens.
A wave happens at phase of the cardiac phase
End diastole.
c wave happens at phase of the cardiac phase
Early systole
v wave happens at phase of the cardiac phase
Late systole
y descent happens at phase of the cardiac phase
Early diastole
x-descent is
Atrial relaxation and descent of the base of the heart.
Afib changes with CVP
A wave disappears
C wave becomes more prominent
Tall cannon a wave is associated with
Junctional rhythm
Cannon a wave caused by
Atrium contracting against a closed tricuspid valve as during AV dissociation,
Large v waves caused by
Regurgitant flow during ventricular contraction, as with TR
Wave seen with tricuspid bulging
C wave
Analysis of CVP; decrease in CVP with increase BP without changes in SVR
The CVP has fallen because of increased cardiac performance.
Analysis of CVP; decrease in CVP with decrease BP without changes in SVR
Decrease CVP is due to increase intravascular volume or venous return.
Analysis of CVP; increase in CVP with increase BP without changes in SVR
The cause of the increased CVP is an increase in volume or venous return
Analysis of CVP; increase in CVP with decrease BP without changes in SVR
the increased CVP is due to decreased cardiac performance.
PPV and CVP
PPV affect both CO and VR.
The transmural pressure is the
Difference between atrial pressure and the extracardiac pressure.
AT low levels of PEEP , the CVP
increases with increased PEEP.
AT high levels of PEEP , the CVP
High PEEP is >15 cm H2O ; CVP increases as the CO is depressed because of impaired RV output.
Advancing the balloon-tip PAC into the pulmonary artery will allow the catheter to wedge and record the
PAWP or PAOP
The pulmonary artery wedge pressure provides an indirect measurement of
Left atrial pressure.
Noninvasive CO and volume assessment use which fundamental technologies:
Ultrasound
Indicator dilution
Pulse contour analysis
Echocardiography used to evaluate
ventricular function
Assess valvular pathology
such as new valve murmur.
