Module 13: Capnography (Part 03) Flashcards
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).
Phase 1 or A-B Gas
How is dead space identified in Phase 1 or A-B Gas?
Dead space is identified as the first upward deviation from baseline.
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.
Phase 2 or B-C Gas (Ascending Phase)
What happens to the levels of CO in phase 2?
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.
Does the gas large conducting airways in phase 2 contain CO2?
Gas exhaled from the large conducting airways contain no CO2/
In this phase, the carbon dioxide concentration curve remains relatively constant, as primarily alveolar gas is exhaled
Phase 3 or C-D gas (alveolar plateau - is flat with a slight upward tilt toward the end)
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
Phase 3 or D
Phase III (D) contains the highest concentration of CO which is known as ____.
end-tidal CO.
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.
Phase O (D-E), where inhalation will begin
When inspiration does begin again, the amount of measure CO. quickly drops to zero. The return to baseline is called _________.
phase 0.1
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.
Phase I from A to B
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.
Phase II is from B to C
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.
Phase III goes from C to D
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.
phase 0 runs from D to E
What are five (5) characteristics of a Capnogram that should be evaluated?
(1) Frequency
(2) Rhythm
(3) Height
(4) Baseline
(5) Shape
If abnormal waveforms are indicated, the following steps are suggested:
(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
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.
Apnea
What are possible causes of apnea?
Possible causes for apnea include cardiac arrest, respiratory arrest, equipment failure, displaced airway adjunct or obstructive sleep apnea (OSA)
This is defined as the buildup of carbon dioxide as a result of insufficient elimination of the byproduct. Respiratory rate may vary.
Hypoventilation
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).
between 12 breaths per minute and 20 breaths per minute in adult
Explain the capnogram of a patient with hypoventilation
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.
The hallmark sign of hypoventilation is a CO. level_________________ in the presence of normal perfusion/circulation and metabolism
elevated above 45 mmHg
Possible causes for hypoventilation
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.