Module 13: Capnography (Part 03)

Question 1

This phase is where gas is exhaled from the large conducting airways, which contain essentially no carbon dioxide. The exhalation cycle begins with air leaving the trachea, posterior pharynx, mouth and nose (dead space).

Answer 1

Phase 1 or A-B Gas

Question 2

How is dead space identified in Phase 1 or A-B Gas?

Answer 2

Dead space is identified as the first upward deviation from baseline.

Question 3

In this phase, CO. from the alveoli begins to reach the upper airway and mix with the dead space air. This causes a rapid raise in the amount of CO.

Answer 3

Phase 2 or B-C Gas (Ascending Phase)

Question 4

What happens to the levels of CO in phase 2?

Answer 4

and CO. is now detected in exhaled air, identified as the gradual upslope of the horizontal line between the end of phase I and the beginning of inhalation or phase III, the respiratory cycle.

Question 5

Does the gas large conducting airways in phase 2 contain CO2?

Answer 5

Gas exhaled from the large conducting airways contain no CO2/

Question 6

In this phase, the carbon dioxide concentration curve remains relatively constant, as primarily alveolar gas is exhaled

Answer 6

Phase 3 or C-D gas (alveolar plateau - is flat with a slight upward tilt toward the end)

Question 7

This phase shows the end of exhalation. The end of the breath cycle contains the highest concentration of CO., which is labeled the end-tidal CO.. This is the number seen on the monitor

Answer 7

Phase 3 or D

Question 8

Phase III (D) contains the highest concentration of CO which is known as ____.

Answer 8

end-tidal CO.

Question 9

In this stage, Oxygen fills the airway and CO. levels drop back to zero. Identified as the rapid descent at the end of the respiratory cycle. When inspiration does begin again, the amount of measure CO. quickly drops to zero.

Answer 9

Phase O (D-E), where inhalation will begin

Question 10

When inspiration does begin again, the amount of measure CO. quickly drops to zero. The return to baseline is called _________.

Answer 10

phase 0.1

Question 11

This phase represents the waveform baseline. There should be little or no CO. during this phase because this represents the inspiratory phase of the respiratory cycle.

Answer 11

Phase I from A to B

Question 12

This phase shows the rise in CO, as the dead space ventilation mixes with alveolar gas. This part of ventilation involves the trachea, main stem bronchus and airways.

Answer 12

Phase II is from B to C

Question 13

This phase represents the alveolar plateau. This part of ventilation involves mostly alveolar gas. D is the point at the end of expiration, just before inspiration, where etCO, is measured.

Answer 13

Phase III goes from C to D

Question 14

This phase is the end of the waveform segment, a rapid, sharp down stroke indicating a drop in CO2 levels and the beginning of inspiration.

Answer 14

phase 0 runs from D to E

Question 15

What are five (5) characteristics of a Capnogram that should be evaluated?

Answer 15

(1) Frequency
(2) Rhythm
(3) Height
(4) Baseline
(5) Shape

Question 16

If abnormal waveforms are indicated, the following steps are suggested:

Answer 16

(1) Check the patient’s status
(2) Check the patient’s sampling line system to rule out any sampling line system issues
(3) Compare the capnogram with other physiological parameters

Question 17

The standard definition of this is no breath for 10 seconds or longer. These may be central in nature with no respiratory effort, or obstructive, respiratory effort without air movement.

Answer 17

Apnea

Question 18

What are possible causes of apnea?

Answer 18

Possible causes for apnea include cardiac arrest, respiratory arrest, equipment failure, displaced airway adjunct or obstructive sleep apnea (OSA)

Question 19

This is defined as the buildup of carbon dioxide as a result of insufficient elimination of the byproduct. Respiratory rate may vary.

Answer 19

Hypoventilation

Question 20

Hypoventilation may result during normal (generally between ____ breaths per minute and ____ breaths per minute in adult) respiratory rate, slow respiratory rate (bradypnea) or insufficient tidal volume (hypopnea).

Answer 20

between 12 breaths per minute and 20 breaths per minute in adult

Question 21

Explain the capnogram of a patient with hypoventilation

Answer 21

The breathing pattern or rhythm is usually regular. The shape or
morphology of the capnogram is normal with rapid increase in phase II, gradual, smooth and possibly prolonged (effort dependent) upslope during phase III, and an abrupt decent to baseline during inhalation.

Question 22

The hallmark sign of hypoventilation is a CO. level_________________ in the presence of normal perfusion/circulation and metabolism

Answer 22

elevated above 45 mmHg

Question 23

Possible causes for hypoventilation

Answer 23

decrease in respiratory rate, decrease in tidal volume, chest compressions during CPR, obesity hypoventilation syndrome (OHS) or use of central nervous system (CNS) depressant drugs.

Question 24

This is defined as a low carbon dioxide level resulting from excessive elimination through rapid or deep breathing or from metabolic acidosis. Respiratory rate may vary.

Answer 24

Hyperventilation

Question 25

Explain the capnogram of a patient with hyperventilation.

Answer 25

The breathing pattern or rhythm is usually regular. The shape or morphology of the capnogram is normal with a rapid increase in phase II, gradual, smooth and possibly shortened or peaked upslope during phase III, and an abrupt descent to baseline during inhalation.

Question 26

The hallmark sign of hyperventilation is a __________________in the presence of normal perfusion/circulation and metabolism.

Answer 26

decreased CO. Level below 35 mmHg

Question 27

What are the possible causes for hyperventilation?

Answer 27

Possible causes for hyperventilation include anxiety/panic disorder, excessive exercise beyond VO. max, increase in respiratory rate or increase in tidal volume.

Question 28

During CPR, a measurable amount of carbon dioxide is produced during the delivery of effective (proper rate, depth and recoil) chest compressions. Manual compressions have been shown to deliver what?

Answer 28

20 percent of normal systemic blood flow when performed according to current American Heart Associations (AHA) guidelines for resuscitation.

Question 29

What happens during cardiorespiratory arrest?

Answer 29

However, levels should remain consistent with effective compressions. During cardiorespiratory arrest, there is a massive systemic buildup of carbon dioxide. Return of spontaneous circulation (ROSC) results in a rapid and abrupt influx of CO.

Question 30

In this case, respiratory rate may vary but is generally rapid and above a rate of 20 breaths per minute. The breathing pattern or rhythm is usually regular and occurs at least once every three seconds. The shape or morphology of the capnogram is normal with a rapid increase in phase II, gradual and smooth upslope during phase III, and an abrupt descent during phase 0 back to baseline during inhalation.

Answer 30

Tachypnea with hypocarbia,

Question 31

How much are the etCO levels of Tachypnea with hypocarbia?

Answer 31

EtCO. levels are generally lower than normal.

Question 32

What are the causes of tachypnea with hypocarbia?

Answer 32

Possible causes for tachypnea with hypocarbia include pulmonary embolism, diabetic ketoacidosis, hyperosmolar hyperglycemic nonketonic coma (HHNC) or pain

Question 33

This is a form of hypoventilation.

Answer 33

Bradypnea and Hypercapnia

Question 34

This is defined as the presence of an abnormally high level of carbon dioxide in the circulating blood.

Answer 34

Hypercapnia

Question 35

During hypercapnia, respiratory rate may vary but is generally slow and below a rate of ________________, representing bradypnea.

Answer 35

12 breaths per minute

Question 36

Explain the capnogram of Bradypnea and Hypercapnia

Answer 36

On the capnogram, the increased levels of carbon dioxide being exhaled result in an enlarged waveform with a rapid increase in phase II, gradual and smooth upslope during phase III, and an abrupt descent during phase 0 back to baseline during inhalation.

Question 37

How are the end tidal volume of a patient with Bradypnea and Hypercapnia

Answer 37

End- tidal carbon dioxide levels are generally elevated above normal. The breathing pattern, or rhythm, is usually regular and occurs less often than once every five seconds.

Question 38

In rebreathing, respiratory rate may vary but is generally between what?

Answer 38

12 breaths per minute and 20 breaths per minute in the adult patient. The breathing pattern or rhythm is usually normal and occurs approximately once every three to five seconds. (etCO may vary due to hyperventilation)

Question 39

Explain the capnography of Rebreathing CO2.

Answer 39

The shape or morphology of the capnogram is normal with a rapid increase in phase II, gradual and smooth upslope during phase III, and an abrupt descent to baseline during inhalation. The characteristic pattern for rebreathing CO. is an increase or rise in phase I or baseline.

Question 40

Possible causes of Rebreathing CO2.

Answer 40

with a history of asthma or chronic obstructive pulmonary disease (COPD), rebreathing exhaled gas (tent effect), or malfunction in the exhalation valve of the bag valve mask (BVM) or ventilator.

Question 41

This is the spasmodic closure of the larynx. Respiratory rate may vary but is generally between 12 breaths per minute and 20 breaths per minute in the adult patient. The breathing pattern or rhythm is usually regular and occurs approximately once every three to five seconds

Answer 41

Laryngospasm

Question 42

Explain the capnography of a patient with Partial Airway Obstruction - Laryngospasm

Answer 42

The shape or morphology of the capnogram is normal with a rapid increase in phase II, gradual and smooth upslope during phase III, and an abrupt descent during phase 0 back to baseline during inhalation. In some cases of partial airway obstruction, there is the presence of noisy respirations or inspiratory stridor. The waveform becomes erratic as the changes occur in the airflow. As the obstruction progresses, the waveform will become progressively more dampened.

Question 43

Possible causes of Partial Airway Obstruction - Laryngospasm

Answer 43

Possible causes of partial airway obstruction include relaxation of the upper airway or secretions in the airway.

Question 44

In this case, the respiratory rate may vary but is generally greater than 20 breaths per minute (tachypnea) in the adult patient and is often accompanied by a reduced tidal volume. Additionally, wheezes or rhonchi may be present. The breathing pattern or rhythm is usually regular and occurs once every three seconds or less in the compromised patient.

Answer 44

Lower Airway Obstruction - Bronchospasm

Question 45

Explain the capnography of a patient with Lower Airway Obstruction - Bronchospasm

Answer 45

The typical shape or morphology of the capnogram is abnormal with a marked phase II to phase III curve with a shark fin appearance, and an abrupt descent during phase 0 back to baseline during inhalation.

Question 46

This is seen in more severe bronchospasm.

Answer 46

Shark Fin

Question 47

Possible causes of Lower Airway Obstruction - Bronchospasm

Answer 47

Possible causes for lower airway obstruction (bronchospasm) include asthma, allergy or chronic obstructive pulmonary disease (COPD), i.e., emphysema/bronchitis or pulmonary edema.

Question 48

This is the shallow breathing, is considered less than 0.5 liters in an adult patient.

Answer 48

Hypopnea

Question 49

This is the low respiratory rate, may vary but is generally less than 12 breaths per minute

Answer 49

Bradypnea

Question 50

Explain the capnography of a patient with Hypopnea with Bradypnea

Answer 50

The shape or morphology of the capnogram is abnormal with short, non- plateauing waveform and slow respiratory rate. Often, this is followed by a higher concentration of CO, when a deep breath is taken.

Question 51

This is often seen during procedural sedation or with use of opioids.

Answer 51

Hypopnea with Bradypnea

Question 52

Possible causes of Hypopnea with Bradypnea

Answer 52

Possible causes for hypopnea with bradypnea include narcotic overdose, central nervous system (CNS) depression, heavy sedation or stroke.

Question 53

This case in an adult patient and often accompanied by a reduced tidal volume and wheezes or rhonchi may be present. The breathing pattern or rhythm is usually regular and occurs once every three seconds or less in the compromised patient. The shape or morphology of the capnogram is abnormal with a marked phase Il to phase III curve with a shark fin appearance, and an abrupt descent during phase 0 back to baseline during inhalation.

Answer 53

asthma, emphysema, or COPD

Question 54

Explain the capnogram of a patient with asthma, emphysema, or COPD

Answer 54

However, the loss of the alpha angle between the termination of phase II and the onset of phase III is the hallmark of bronchospasm.

Question 55

These are used when a patient’s heart has stopped. The goal of these are to provide blood flow to the brain and vital organs, such as the heart and lungs.

Answer 55

chest compressions

Question 56

The rate and depth of chest compressions determines what?

Answer 56

the perfusion, or blood flow to the lungs, also known as pulmonary perfusion

Question 57

Pulmonary perfusion determines what?

Answer 57

Pulmonary perfusion determines the amount of CO. that is delivered to the lungs for removal when the ventilation is provided.

Question 58

Why is monitoring capnography during CPR important?

Answer 58

Monitoring capnography during CPR can alert the clinician that compressions are ineffective due to rescuer fatigue or technique. A decrease in the etCO, parameter and waveform trends can provide objective data indicating a need to reevaluate clinician technique.