Anesthesia Monitoring & Record Keeping Flashcards
What are 4 ways to monitor circulation? What should be recorded?
- ECG - electrical activity of the heart
- blood pressure
- esophageal stethoscope
- pulse palpation, mm color/capillary refill (can be affected by drugs)
- HR
- BP
- pulse quality
- ECG rhythm abnormalities
What is the standard lead placement for a 3-lead ECG system? How are the 3 leads read?
white = RA; black = LA; red = LL
- RA to LA
- RA to LL
- LA to LL
(cycle through all 3 until the best trace is achieved)
How can the ECG leads be troubleshooted if there is a poor-quality ECG trace or 60-cycle interference?
- improper skin contact
- no gel (more long-term than alcohol)
- worn leads
How can the ECG leads be troubleshooted if there is a small trace size?
- increase gain
- improve lead contact
How can the ECG leads be troubleshooted if there is an isoelectric trace or double counting?
(PQRS looks the same)
- use a different lead
- move leads further apart
What should be done is there is a sudden loss of an ECG trace?
could be cardiac arrest, but…
- confirm pulse and pulse oximeter
- check is leads fell off
What does mean arterial pressure indicate?
organ inflow pressure
- remember, a normal ECG can be present with cardiac arrest
What 3 things determine systolic blood pressure? What does this indicate?
- left ventricular stroke volume
- vascular compliance
- backward reflected waves
left ventricular wall tension (afterload)
What determines pulse pressure? What does this indicate?
difference between systolic and diastolic blood pressure
stroke volume
What determines mean arterial pressure? What does this indicate?
average pressure over the cardiac cycle
inflow pressure for most organ systems
What determines diastolic blood pressure? What does this indicate?
systemic vascular resistance
pressure the left ventricle must overcome to begin ejecting blood into the aorta
Why is it so important to monitor blood pressure?
no blood flow = no oxygen delivery to organs = ischemic injury
What 3 things is intraoperative hypotension associated with?
- increase in mortality
- increase in major adverse cardiac/cerebrovascular events
- increase in perioperative mortality
What 2 things does tissue perfusion and oxygen delivery depend on? How does this relate to blood pressure?
- cardiac output
- blood oxygen content
BP is a great indicatory of perfusion and is an indirect measure (changes often and is an estimation)
How does Doppler BP work? What does it measure?
ultrasound signal hits moving RBCs in the artery, returning echoes detected and converted into a sound (continuous)
systolic BP
What 2 qualities of the sound of Doppler BP machines are affected by RBCs?
- frequency is associated with RBC velocity
- intensity is associated with the number of RBCs detected
How does oscillometric BP work? What is the most accurate measurement?
automated intermittent measurement of intracuff pressure oscillations (inflation vs. deflation) due to pulsations of the artery
MAP —> SAP and DAP are calculated based on manufacture algorithms
What is the gold standard for measuring BP?
invasive/direct BP by arterial catheters (requires special transducer and flush; more difficult than IV catheters)
- most accurate and definitive measurement of SAP, MAP, and DAP
How large should a BP cuff be? What happens when it is too large or small?
width should be 40% of limb circumference (30-50%)
- TOO LARGE = underestimate of BP
- TOO SMALL = overestimate of BP
(too loose or tight = inaccurate measurements)
What commonly causes inaccurate measurements of BP during long procedures?
Doppler gel dries out
What BP machines work best for small and large patients?
> 7 kg = oscillometric
< 7 kg = Doppler, but man underestimate SAP
What are the 3 most common errors seen in BP measurement?
- hypertension tends to be underestimated
- hypotension tends to be overestimated
- arrhythmias and profound tachycardia or bradycardia reduce the accuracy of measurements, especially in oscillometric measurements
What is a major pro and con to using esophageal stethoscopes?
easy to use on draped patients
more things down the esophagus makes regurgitation more common
What is percent oxygen saturation (SaO2) a measurement of? What should the normal arterial SaO2 and venous SvO2 be?
total number of hemoglobin binding sites occupied by oxygen molecules
- SaO2 > 97% (estimate of SpO2)
- SvO2 ~ 75%
How does pulse oximetry equipment work? What is required for it to work?
- red and infrared light are emitted from a probe, which passes through or is reflected off tissue and detected by a sensor
- SpO2 calculations are based off of the differences in light absorption between saturated and desaturated hemoglobin
pulsatile flow —> won’t work in a patent in cardiac arrest
What additional reading is achieved on a pulse oximeter?
heart rate
At which SpO2 levels does hypoxemia and dangerous hypoxemia occur?
< 95%
< 90% (PaO2 < 60 mmHg)
What which SaO2, PaO2, and PCV levels is visual detection of hypoxemia possible?
SaO2 < 85%
PaO2 < 50 mmHg
PCV > 15
What is ventilation defined by? How is it monitored?
PaCO2, which is indirectly measured by end-tidal CO2
capnometer —> measures CO2 concentration of inspired and expired air
What are the 2 forms of capnography?
- MAINSTREAM - sensor is at the patient end and immediate real-time readings are achieved breath to breath
- SIDE-STREAM - sampling port is at the patient end, which creates a lag of approximately 2-3 seconds
What does end-tidal CO2 reflect? How is it seen on a capnograph?
alveolar gas —> estimation of PaCO2
end plateau phase
What does an increase in inspired CO2 on a capnograph indicate?
should be 0 —> can indicate equipment dead space
What 3 things is end-tidal CO2 determined by?
- rate of CO2 production
- rate of CO2 transport to the lungs - hypotension, low cardiac output, and open chest surgeries can cause ETCO2 to be artificially low
- rate of CO2 elimination from the lungs - increased RR would cause an increased ETCO2
Capnographs:
How can ventilation be monitored without equipment?
- chest excursion
- rebreathing bag movement
- frequency of breathing
- quality and character or chest movements: abdominal effort, normal volume movement, panting, irregular/infrequent breathing
(all should be monitored, even if capnography and pulse oximeters are used)
How is temperature monitored during surgery?
esophageal/rectal probes = core temps
- hypothermia is most common in small patients and in long procedures
- hyperthermia is more rare, but seen with porcine malignant hyperthemia, iatrogenic, or in winter breeds
What are important aspects of a trained and attentive anesthetist?
- knowledgable about how, what, and when to monitor
- recognizes areas of concern in a timely manner
- troubleshoots problems with the team
- should not be multitasking —> no doing dentals while monitoring
- uses hands-on evaluation AND monitors
In what intervals should recorded physiological parameters be taken?
5 minutes —> any longer can cause a miss in trends
What peri-operative recordings are important to be taken?
- drugs (can help with future anesthetic events)
- fluids
- oxygen flow rates
- equipment, like breathing systems, ventilators, ET tube size
- anything regarding patient management
