Anesthesia Monitoring

Question 1

When attempting to reduce electrical skin resistance upon attaching a patient up to an ECG monitor, why is alcohol not a good option?

Answer 1

short duration of effect, skin irritation, flammability

Question 2

T or F: ECG monitoring during anesthesia can be used as a diagnostic ECG

Answer 2

False; most patient positioning and lead locations are incompatible w/ diagnostic ECG benchmarks - can only use it for electrical rate and rhythm

Question 3

What two cardiac principles can blood pressure readings give you an idea of?

Answer 3

cardiac contraction (cardiac output) and tissue perfusion

Question 4

Systolic blood pressure is an indication of what two values?

Answer 4

stroke volume and arterial compliance

Question 5

Diastolic blood pressure is dependent upon what?

Answer 5

systemic vascular resistance

Question 6

Where are various locations you can place a pulse ox monitor?

Answer 6

tongue, lips, vaginal mucosa, prepuce, base of tail, rectum

Question 7

Hypothermia does what to a patient’s anesthetic requirement and heart rate?

Answer 7

lowers them (bradycardia)

Question 8

Hyperthermia does what to a patient’s anesthetic requirement and metabolic rate?

Answer 8

increases them

Question 9

What kind of blood pressure reading will you get if the cuff is too tight? Too loose? Too narrow? Too wide?

Answer 9

• Tight: an incorrectly low BP measurement
• Loose: incorrectly high BP measurement
• Narrow: too high
• Wide: too low

Question 10

What features could decrease the accuracy of a blood pressure reading using an oscillometer?

Answer 10

patient movement, incorrect cuff placement/size, leaks, maintenance at heart level

Question 11

What are the advantages of using a mainstream capnography reader over a sidestream?

Answer 11

• less maintenance
• less disposable parts
• no scavenging
• fast response time
• no standard gas

Question 12

What are the disadvantages of using a mainstream capnography reader over a sidestream?

Answer 12

• fragile sensor
• adds weight/dead space to tube
• longer warm up time
• only for O2 and CO2

Question 13

What are the advantages of using a sidestream capnography reader over a mainstream?

Answer 13

• multi gas analyzer
• away from patient
• automatic zeroing and calibration
• inexpensive and light interface

Question 14

What are the disadvantages of using a sidestream capnography reader over a mainstream?

Answer 14

• more disposable parts
• longer response time
• calibration cylinder
• scavenging required
• water tap

Question 15

What are the benefits of using a capnography system in monitoring anesthesia?

Answer 15

Allows easy detection of:

• proper intubation
• arrest
• hypovolemia
• malfunction
• MH
• resp/circulation
• changes in metabolic rate

Question 16

What information does a pulse ox monitor provide?

Answer 16

arterial hemoglobin oxygen saturation, as well as heart rate and rhythm

Question 17

How does a pulse ox sensor detect the SpO2?

Answer 17

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

Question 18

What is the difference between SaO₂ and SpO₂?

Answer 18

SaO₂ = O₂ saturation obtained from a co-oximeter from an arterial blood sample

SpO₂ = arterial O₂ saturation obtained by the pulse oximeter

Question 19

Why should oxygen saturation continue to be monitored during recovery?

Answer 19

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

Question 20

T or F: pulse oximeters quantify available hemoglobin

Answer 20

false; thus, an anemic patient might still have a normal saturation % but tissue oyxgenation may be compromised d/t low blood volume

Question 21

What percent of O2 saturation on a pulse ox indicates a problem with oxygenation?

Answer 21

< 90% saturation; corresponds to a PaO2 of about 60 mmHg (mild hypoxemia)

Question 22

Define end tidal CO2

Answer 22

maximum CO2 concentration that is measured at the end of expiration

Question 23

What is the idea behind chemical colorimetric analysis?

Answer 23

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

Question 24

What are some downsides to using the chemical colorimetric analysis over capnography machines?

Answer 24

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

Question 25

What does the plateau portion of expiration on a capnograph waveform represent?

Answer 25

exhaled alveolar gas concentration, ending with the highest point, which is the end tidal CO2

Question 26

What are some reasons for having an EtCO2 greater than the normal range?

Answer 26

obesity, deep plane of anesthesia, opioid resp depression, position of patient impeding breathing

Question 27

What does the capnograph represent?

Answer 27

Hypoventilation (hypercapnea)

Question 28

What does this capnograph represent?

Answer 28

Rebreathing

Question 29

What does this capnograph represent?

Answer 29

Airway obstruction

Question 30

Answer 30

Mechanical ventilation (with a sampling line leak)