Anesthesia Monitoring Flashcards
When attempting to reduce electrical skin resistance upon attaching a patient up to an ECG monitor, why is alcohol not a good option?
short duration of effect, skin irritation, flammability
T or F: ECG monitoring during anesthesia can be used as a diagnostic ECG
False; most patient positioning and lead locations are incompatible w/ diagnostic ECG benchmarks - can only use it for electrical rate and rhythm
What two cardiac principles can blood pressure readings give you an idea of?
cardiac contraction (cardiac output) and tissue perfusion
Systolic blood pressure is an indication of what two values?
stroke volume and arterial compliance
Diastolic blood pressure is dependent upon what?
systemic vascular resistance
Where are various locations you can place a pulse ox monitor?
tongue, lips, vaginal mucosa, prepuce, base of tail, rectum
Hypothermia does what to a patient’s anesthetic requirement and heart rate?
lowers them (bradycardia)
Hyperthermia does what to a patient’s anesthetic requirement and metabolic rate?
increases them
What kind of blood pressure reading will you get if the cuff is too tight? Too loose? Too narrow? Too wide?
- Tight: an incorrectly low BP measurement
- Loose: incorrectly high BP measurement
- Narrow: too high
- Wide: too low
What features could decrease the accuracy of a blood pressure reading using an oscillometer?
patient movement, incorrect cuff placement/size, leaks, maintenance at heart level
What are the advantages of using a mainstream capnography reader over a sidestream?
- less maintenance
- less disposable parts
- no scavenging
- fast response time
- no standard gas
What are the disadvantages of using a mainstream capnography reader over a sidestream?
- fragile sensor
- adds weight/dead space to tube
- longer warm up time
- only for O2 and CO2
What are the advantages of using a sidestream capnography reader over a mainstream?
- multi gas analyzer
- away from patient
- automatic zeroing and calibration
- inexpensive and light interface
What are the disadvantages of using a sidestream capnography reader over a mainstream?
- more disposable parts
- longer response time
- calibration cylinder
- scavenging required
- water tap
What are the benefits of using a capnography system in monitoring anesthesia?
Allows easy detection of:
- proper intubation
- arrest
- hypovolemia
- malfunction
- MH
- resp/circulation
- changes in metabolic rate
What information does a pulse ox monitor provide?
arterial hemoglobin oxygen saturation, as well as heart rate and rhythm
How does a pulse ox sensor detect the SpO2?
it analyzes the differential absorption spectra (920-960 nm for oxyHb; 640-660 nm for deoxyHb) of oxygenated and deoxygenated Hb, which provides a value for O2 saturation; also differentiates arterial and venous blood flow
What is the difference between SaO2 and SpO2?
SaO2 = O2 saturation obtained from a co-oximeter from an arterial blood sample
SpO2 = arterial O2 saturation obtained by the pulse oximeter
Why should oxygen saturation continue to be monitored during recovery?
a decrease in oxygenation is possible since the patient is no longer breathing a high inspired oxygen concentration (FiO2)
pulse ox sensors are unable to assess inadequacy of lung function at PaO2 values >100-120 mmHg as in the case of patients breathing 100% during GA
T or F: pulse oximeters quantify available hemoglobin
false; thus, an anemic patient might still have a normal saturation % but tissue oyxgenation may be compromised d/t low blood volume
What percent of O2 saturation on a pulse ox indicates a problem with oxygenation?
< 90% saturation; corresponds to a PaO2 of about 60 mmHg (mild hypoxemia)
Define end tidal CO2
maximum CO2 concentration that is measured at the end of expiration
What is the idea behind chemical colorimetric analysis?
it’s a pH-sensitive chemical indicator in a plastic chamger that connects to the gas stream b/t the ET tube and the anesthesia circuit - changes color when exposed to CO2 during expiration/inspiration
What are some downsides to using the chemical colorimetric analysis over capnography machines?
semi-quantitative - can’t measure accurate concentration of CO2 and can’t detect low concentrations of CO2, so can give false negatives (e.g. CPR); pH/color change can be affected by drugs, mucus, gastric contents
What does the plateau portion of expiration on a capnograph waveform represent?
exhaled alveolar gas concentration, ending with the highest point, which is the end tidal CO2
What are some reasons for having an EtCO2 greater than the normal range?
obesity, deep plane of anesthesia, opioid resp depression, position of patient impeding breathing
What does the capnograph represent?
Hypoventilation (hypercapnea)
What does this capnograph represent?
Rebreathing
What does this capnograph represent?
Airway obstruction
Mechanical ventilation (with a sampling line leak)
