RCS Capnography Flashcards
4 Main Uses of Capnography
Severity of asthma
Monitoring head injured patients
Cardiac arrest
Tube confirmation
numeric measurement of CO2
Capnometer
a real-time waveform record of the concentration of carbon dioxide in the
respiratory gases
Capnogram
the graphical representation of the concentration or partial pressure of expired CO2
during a respiratory cycle in a “waveform” format
Capnograph
the level of (partial pressure of) carbon dioxide released at end of expiration.
End Tidal CO2 (ETCO2 or PetCO2)
Limitation of CAPNOGRAPHY
- Critically ill patients often have rapidly changing dead
space and Ventilation/perfusion mismatch - Higher rates and smaller TV can increase the amount of
dead space ventilation - High mean airway pressures and PEEP(POSITIVE END-EXPIRATORY PRESSURE) restrict alveolar perfusion,
leading to falsely decreased readings - Low cardiac output will decrease the reading
Factors that affect CO2 levels:
- INCREASE IN ETCO2
- Increased muscular activity
- Increased cardiac output
(during resuscitation) - Effective drug therapy for
bronchospasm - Hypoventilation
Factors that affect CO2 levels:
- DECREASE IN ETCO2
- Decreased muscular activity
- Decreased cardiac output
(during resuscitation) - Bronchospasm
- Hyperventilation
Normal Range of EtCO2
35-45 mmHg
ETCO2 Less Than 35 mmHg =
- pH Increases (Alkalosis)
“Hyperventilation/Hypocapnia“
ETCO2 Greater Than 45 mmHg =
- pH Decreases (Acidosis)
“Hypoventilation/Hypercapnia”
CAPNOGRAPHY: Non-Intubated Applications
Bronchospasms: Asthma, chronic obstructive
pulmonary disease, Anaphlyaxis
Hypoventilation: Drugs, Stroke, congestive heart
failure, Post-Ictal
Shock & Circulatory compromise
Hyperventilation Syndrome: Biofeedback
CAPNOGRAPHY: Intubated Applications
Verification of Endotracheal Tube placement
Endotracheal tube surveillance during transport
Control ventilations during increased ICP(increase
intracranial pressure)
Cardiopulmonary resuscitation
Disposable detector
- Color changes in the presence of CO2
- This occurs when CO2 is exhaled, causing the pH to
decrease changing the disc from purple to tan.
Colorimetric
Measures the percentage of CO2 that is present through the
third phases of expiration cycle. Based on CO2 diffusion from
pulmonary arterial blood carried to the pulmonary capillary
beds of the alveoli – where gas exchange occurs.
Infrared Monitoring
This type of infrared monitoring tech., sensor located
directly in pt.’s
breathing circuit
- Used primarily on
intubated patients
Mainstream
This type of infrared monitoring tech., Sample is removed
from pt.’s airway and
delivered to a distant
sensor.
- Can be used on
nonintubated
patients
Sidestream
Square box waveform, ETCO2 35-45 mm Hg
Normal Waveforms
Prolonged waveform
ETCO2 >45 mm Hg
Management:
Hypoventilation
- Assist ventilations or intubate as needed
Shortened waveform
ETCO2 < 35 mm Hg
Management:
Hyperventilation
- If conscious gives biofeedback. If ventilating, give slow ventilations.
During CPR sudden increase of ETCO2 above 10-15 mm Hg
Management:
ROSC (Return of Spontaneous Circulation)
- check pulse
▪ Shark fin waveform
▪ With or without prolonged expiratory phase
▪ Can be seen before actual attack
▪ Indicative of Bronchospasm
Obstructive airway
▪ Angled, sloping down stroke on the waveform
▪ In adults may mean ruptured cuff or tube too small
▪ In pediatrics tube too small
Management:
Patient breathing around ETT
- Assess patient, Oxygenate, ventilate and possible re-intubation
Absence of waveform
Absence of ETCO2
Management:
Esophageal Tube
- Re-Intubate
