Module 13: Capnography (Part 02)

Question 1

Capnography comes from the Greek word _________________.

Answer 1

capno, which means smoke

Question 2

This is a noninvasive, continuous measurement of exhaled carbon dioxide (C) concentration during respiration.

Answer 2

Capnography

Question 3

Capnography is used to describe the technique in which carbon dioxide concentration is displayed as a graphic waveform called a _____________.

Answer 3

Capnogram

Question 4

This is the technique in which carbon dioxide concentration is displayed as a numeric reading.

Answer 4

Capnometry

Question 5

How is capnography applied?

Answer 5

Historically, capnography helped the anesthesiologist to identify ventilation situations that can lead to hypoxia if uncorrected. Currently, capnography also helps in the swift differential diagnosis of hypoxia before hypoxia leads to irreversible brain damage. Today, the utility of capnography has been extended outside of the operating room arena to emergency rooms, endoscopic suites, X-ray rooms, on-site emergency and Sauma fields.

Question 6

They require capnography to be used to monitor ventilation during moderate to heavy sedation and recommends using capnography to judge the effectiveness of chest compression during CPR.

Answer 6

American Society of Anesthesiologists (ASA) and Association of Anesthetists of Great Britain and Ireland (AAGBI)

Question 7

Why is capnography important?

Answer 7

By monitoring CO. concentration, the clinician has an indication of subtle pathological disturbances of metabolic, cardiovascular and respiratory systems.

For example, when a patient’s ventilation and perfusion, as measured by blood pressure (BP) or cardiac output, remain constant, the level of etCO. would increase or decrease in parallel with the body metabolic temperature.

Question 8

This represents the concentration of CO. (as partial pressure in a mixed gas) at the end of expiration of a normal tidal volume, or the end- tidal breath, and thus is a measure of ventilation.

Answer 8

End-tidal carbon dioxide (etCO.)

Question 9

The normal range of etCO is what?

Answer 9

The normal range for etCO, is between 35 millimeters of mercury (mmHg) to 45 millimeters of mercury (mmHg).

Question 10

Capnography monitors what?

Answer 10

Capnography monitors CO. removal during breathing and provides a breath- by-breath assessment of the patient’s ventilatory status.

Question 11

This is a graphic tracing of the inhaled and exhaled partial pressure of CO. mmHg in each respiratory cycle plotted against time.

Answer 11

time- based waveform

Question 12

The CO. waveform changes immediately when there is what?

Answer 12

When there is a change in breathing, and this is the first sign of a respiratory problem

Question 13

This is the frequency of respiratory cycle and the volume, or amplitude of each respiratory movement, is referred to as the respiratory depth.

Answer 13

respiratory rate

Question 14

During normal breathing, these are adjusted to regulate CO. levels in the blood.

Answer 14

respiration rate and depth are adjusted to regulate CO. levels in the blood.

Question 15

Why is the respiration rate provided by capnography important?

Answer 15

because it is an airway respiration rate which is both quantified (counted) and qualified (verified by CO. cycle) measured at the airway, which can alert clinicians to changes in the patient’s ventilatory status.

Question 16

What happens when the respiration rate and depth increase?

Answer 16

when the respiration rate and depth increase, more carbon dioxide is removed (higher etCO.), which results in less CO. in the body. As respiration rate and depth decrease, less carbon dioxide is removed (lower etCO.), which results to more CO. in the body.

Question 17

Explain the relationship between etCO and respiration rate?

Answer 17

Inverse Relationship (When respiratory rate decreases, etCO increases and in early respiratory depression when respiratory rate increases, the etCO. decreases)

Question 18

This monitors oxygenation

Answer 18

Pulse Oximetry

Question 19

This monitors ventilation

Answer 19

Capnography

Question 20

This is the numerical value from the pulse oximeter, reflects the percentage of red blood cells saturated with oxygen. It does not indicate what rate the patient is breathing, and can be a late indicator of respiratory problems. Additionally, the use of supplemental oxygen can further delay the detection of airway compromise when monitoring the delayed effect of ventilation with pulse oximetry.

Answer 20

SpO

Question 21

What does SpO reflect?

Answer 21

reflects the percentage of red blood cells saturated with oxygen

Question 22

This is the the numerical value from capnography, reflects the effectiveness of ventilation and a waveform graphic of each breath in real time.

Answer 22

EtCO

Question 23

What does EtCO reflect?

Answer 23

reflects the effectiveness of ventilation and a waveform graphic of each breath in real time.

Question 24

This describes the numerical measurement of the concentration of carbon dioxide in an exhaled breathe.

Answer 24

Capnometry

Question 25

This refers to the graphical representation of the concentration of inhaled and exhaled CO. This type of graph is referred to as a waveform

Answer 25

Capnogram

Question 26

This is a surrogate of physiologic dead space, is valuable in assessing the ventilation/perfusion (V/Q) relationship.

Answer 26

PaCO. - PETCO, gradient,

Question 27

A change in gradient denotes what?

Answer 27

A change in gradient denotes unstable circulatory hemodynamics or variable alveolar ventilation as a result of dynamic changes in compliance or resistance in the lungs. If the gradient stabilizes over the course of clinical management, the assumption is that alveolar ventilation and perfusion stability have been achieved.

Question 28

What are two (2) main types of Capnogram?

Answer 28

time and volume

Question 29

This form of Capnogram displays changes in CO, during inspiratory and expiratory phases of respiration versus time. An example waveform appears on the left side of the screen. It is important to note that EtCO. is only one data point on the CO. waveform.

Answer 29

Time capnograms

Question 30

This form of Capnogram displays only expiration. This is used to evaluate the efficiency of lung ventilation by calculating dead spaces.

Answer 30

Volumetric capnograms

Question 31

With a normal waveform respiratory rate may vary, but it is generally between _____breaths per minute and _____ breaths per minute for adults.

Answer 31

12 breaths per minute and 20 breaths per minute

Question 32

The breathing pattern or rhythm is usually regular and occurs approximately once every ___ seconds to ____seconds

Answer 32

The breathing pattern or rhythm is usually regular and occurs approximately once every 3 seconds to 5 seconds

Question 33

Expired air on the other hand, contains about ___ percent to ___ percent carbon dioxide. Since capnography detects only CO. from ventilation, the baseline is normally at zero

Answer 33

Expired air on the other hand, contains about 4 percent to 6 percent carbon dioxide.

Question 34

What are the four (4) phases in capnography?

Answer 34

The capnography waveform shows four phases:
(1) exhaled gas from conducting airways,
(2) a mixture of conducting airways and alveolar air,
(3) the alveolar plateau
(4) and inspired air.

Question 35

in normal capnography there is how many waveforms?

Answer 35

there is only one normal waveform. The waveform should return to baseline, the frequency should match the patients respiratory rate (spontaneous and mechanical) and the height of the waveform or etCO. should be between 35 mmHg and 45 mmHg, which is the normal end- tidal CO. reading