Capnography Ericksen (Exam 1) Flashcards
What organizations require capnography as a standard monitor for every patient under anesthesia?
A. FDA and CDC
B. AANA and ASA
C. WHO and AMA
D. NIH and ADA
B. AANA and ASA
Slide 2
Capnography provides information about which of the following aspects?
A. Ventilation
B. Metabolism
C. Cardiovascular function
D. All of the above
D. All of the above
Slide 2
Which of the following is an effect of hypercarbia?
A. Respiratory alkalosis
B. Respiratory acidosis
C. Decreased cerebral blood flow (CBF)
D. Decreased pulmonary vascular resistance
B. Respiratory acidosis
Slide 2
Which of the following best describes the effect of hypercarbia?
A. Hypercarbia decreases CBF and decrese ICP.
B. Hypercarbia increases CBF and increase ICP.
C. Hypercarbia has no effect on CBF and ICP.
D. Hypercarbia stabilizes CBF and increase ICP.
B. Hypercarbia increases CBF and increase ICP.
Slide 3
True or False:
Hypercarbia causes a decrease in pulmonary vascular resistance.
False
Hypercarbia causes an increase in pulmonary vascular resistance.
Slide 3
True or False:
Potassium shifts from intracellular to intravascular space in hypercarbia.
True
K+ shift INside to OUTside
Slide 3
Which of the following is an effect of hypocarbia on the respiratory system?
A. Respiratory acidosis
B. Respiratory alkalosis
C. No change in respiratory function
D. Respiratory failure
B. Respiratory alkalosis
Slide 4
How does hypocarbia affect cerebral blood flow (CBF)?
A. Increases CBF
B. Decreases CBF
C. Has no effect on CBF
D. Stabilizes CBF
B. Decreases CBF
Slide 4
What happens to potassium levels during hypocarbia?
A. Potassium shifts to the intravascular space
B. Potassium shifts to the intracellular space
C. Potassium levels remain unchanged
D. Potassium is excreted in large amounts
B. Potassium shifts to the intracellular space
Slide 4
True or False:
Hypocarbia decreases pulmonary vascular resistance
True
Slide 4
What is a potential respiratory effect of hypocarbia?
A. Enhanced urge to breathe
B. Blunted normal urge to breathe
C. No change in breathing urge
D. Increased breathing rate
B. Blunted normal urge to breathe
Slide 4
Capnography provides information primarily on which of the following? (Select all that apply-3)
A. Ventilation
B. Pulmonary blood flow
C. Aerobic metabolism
D. Blood glucose levels
A. Ventilation
B. Pulmonary blood flow
C. Aerobic metabolism
Slide 5
In addition to ventilation, capnography provides information on: (Select all that apply-3)
A. Placement of ETT/LMA
B. Integrity of breathing circuit
C. Cardiac output adequacy
D. Renal function
A. Placement of ETT/LMA
B. Integrity of breathing circuit
C. Cardiac output adequacy
Slide 5
The Bohr Equation is used to calculate
A. Physiological dead space
B. Oxygen consumption
C. Carbon dioxide production
D. Pulmonary vascular resistance
A. Physiological dead space
Slide 5
What is dead space?
A. The volume of each breath that participates in gas exchange
B. The volume of each breath that does not participate in gas exchange
C. The total lung capacity
D. The residual volume after exhalation
B. The volume of each breath that does not participate in gas exchange
Slide 6
Which of the following are part of the anatomic dead space?
A. Alveoli
B. Conducting zones of the airway (nose, trachea, bronchi)
C. Pulmonary capillaries
D. Pleural cavity
B. Conducting zones of the airway (nose, trachea, bronchi)
Slide 6
True or False:
Physiologic dead space includes both the anatomic dead space and alveolar dead space.
True
True or False:
Alveolar dead space is the portion of physiologic dead space that does not take part in gas exchange but is within the alveolar space
True
Slide 6
Which of the following conditions can increase alveolar dead space by causing ventilation-perfusion (V/Q) mismatch? (Select 4)
A. Hypovolemia
B. Pulmonary hypotension
C. Pulmonary embolus
D. Asthma
E. Overdistension of the alveoli
A. Hypovolemia
B. Pulmonary hypotension
C. Pulmonary embolus
E. Overdistension of the alveoli
Slide 6
What factors contribute to an increase in alveolar dead space? (Select all that apply-3)
A. Obstruction of the pulmonary circulation by external forces
B. Increased pulmonary blood flow
C. Ventilation of nonvascular airspaces
D. Obstruction of precapillary pulmonary vessels
A. Obstruction of the pulmonary circulation by external forces
C. Ventilation of nonvascular airspaces
D. Obstruction of precapillary pulmonary vessels
Slide 6
Which of the following statements is true about capnometry?
A. It provides a continuous graphical display.
B. It is used to measure oxygen levels.
C. It quantifies CO₂ concentrations in inhaled or exhaled air.
D. It confirms the placement of nasogastric tubes.
C. It quantifies CO₂ concentrations in inhaled or exhaled air.
Slide 7
The method of capnography provides information on: (Select all that apply-3)
A. CO₂ measurement
B. Oxygen uptake
C. Graphic display of time
D. Breath-by-breath CO₂ detection
A. CO₂ measurement
C. Graphic display of time
D. Breath-by-breath CO₂ detection
Slide 7
Capnography provides information on which of the following aspects of patient monitoring?
A. Adequacy of ventilation
B. Integrity of the breathing circuit
C. Placement of endotracheal tubes
D. Blood pressure monitoring
C. Placement of endotracheal tubes
Slide 7
What is the most common representation in time capnography?
A. Volume vs. time plot
B. Pressure vs. time plot
C. Flow vs. time plot
D. CO₂ concentration vs. volume plot
B. Pressure vs. time plot
Slide 8
How are CO₂ concentrations digitally reported in time capnography?
A. As oxygen and nitrogen levels
B. As ‘inspired’ and ‘end tidal’
C. As pH levels
D. As volume and flow
B. As ‘inspired’ and ‘end tidal’
Slide 8
What is the benefit of high-speed settings in time capnography?
A. Provides information about long-term trends
B. Allows appreciation of overall respiratory function
C. User can interpret information about each breath
D. Reduces the resolution of the capnograph
C. User can interpret information about each breath
Slide 8
In which clinical scenario might slow-speed time capnography be particularly useful?
A. During rapid sequence induction
B. For monitoring long-term ventilation trends
C. During cardiopulmonary resuscitation (CPR)
D. When adjusting ventilator settings
B. For monitoring long-term ventilation trends
Slide 8
What are the primary characteristics of side-stream capnography? (select 2)
A. Analyzes gas sample directly in the breathing circuit
B. Aspirates gas sample and analyzes away from airway at a rate of 50 to 200 mL/min
C. Has time delay and rise time
D. Measures oxygen concentration
B. Aspirates gas sample and analyzes away from airway at a rate of 50 to 200 mL/min
C. Has time delay and rise time
Also the most common
S10
Which of the following is true about main-stream capnography?
A. It has a transport time delay
B. It analyzes gas sample directly in the breathing circuit
C. It is less common than side-stream capnography
D. It aspirates gas sample away from the airway
B. It analyzes gas sample directly in the breathing circuit
Also has no time delay; rise time is faster
Slide 10
At which phase is end-tidal CO₂ measured?
A. Phase I
B. Phase II
C. Phase III
D. Phase IV
C. Phase III
Slide 11
Which of the following is NOT a possible method for manufacturers to report end-tidal CO₂?
A. Value just before inspiration
B. Smallest value during expiration
C. Largest value
D. The average at a specific time
B. Smallest value during expiration
Sometimes varies with manufacturers:
- Value just before inspiration
- Largest value
- The average at a specific time
Slide 11
Which condition is associated with increased CO2 production, leading to increased PETCO2?
A) Metabolic alkalosis
B) Fever
C) Hypothermia
D) Bradycardia
B) Fever
slide 12
In the context of increased PETCO2, which of the following is NOT a cause related to increased metabolic rate?
A) Sepsis
B) Seizures
C) Malignant hyperthermia
D) Hypothyroidism
D) Hypothyroidism
slide 12
Select all conditions that can cause increased PETCO2 due to increased CO2 production: (select 5)
A) Increased metabolic rate
B) Fever
C) COPD
D) Sepsis
E) Seizures
F) Malignant hyperthermia
A) Increased metabolic rate
B) Fever
D) Sepsis
E) Seizures
F) Malignant hyperthermia
slide 12
Select all conditions that can cause increased ETCO2 due to decreased alveolar ventilation: (select 4. )
A) COPD (Chronic Obstructive Pulmonary Disease)
B) High spinal anesthesia
C) Hyperventilation
D) Hypoventilation
E) Full muscle paralysis
A) COPD
B) High spinal anesthesia
D) Hypoventilation
E) Neuromuscular disease
- Respiratory center depression, partial muscle paralysis
slide 12
Which equipment issue is most likely to cause rebreathing and an increase in ETCO2 levels?
A) High fresh gas flow
B) Blocked endotracheal tube
C) Exhausted CO2 absorber
D) Increased tidal volume
C) Exhausted CO2 absorber
slide 12
A faulty inspiratory or expiratory valve can result in:
A) Decreased ETCO2
B) Rebreathing of CO2
C) Increased oxygenation
D) Reduced patient ventilation
B) Rebreathing of CO2
slide 12
Which equipment malfunctions can cause increased ETCO2 due to rebreathing? (Select all that apply - 3)
A) Exhausted CO2 absorber
B) Leak in the ventilator circuit
C) Faulty inspiratory valve
D) Increased fresh gas flow
E) Blocked endotracheal tube
A) Exhausted CO2 absorber
B) Leak in the ventilator circuit
C) Faulty inspiratory valve
- or faulty expiratory valve
slide 12
Select all conditions that can cause decreased ETCO2 due to decreased CO2 production and delivery to the lungs: (select 4.)
A) Hypothermia
B) Pulmonary hypoperfusion
C) Pulmonary embolism
D) Hyperthyroidism
E) Hemorrhage
A) Hypothermia
B) Pulmonary hypoperfusion
C) Pulmonary embolism
E) Hemorrhage
- also: cardiac arrest & hypotension
slide 13
Which equipment-related issues can lead to decreased ETCO2 levels? (Select all that apply -4)
A) Ventilator disconnect
B) Esophageal intubation
C) Complete airway obstruction
D) Proper endotracheal tube placement
E) Poor gas sampling
A) Ventilator disconnect
B) Esophageal intubation
C) Complete airway obstruction
E) Poor gas sampling
slide 13
Identify the causes of decreased ETCO2 related to incorrect or malfunctioning equipment: (Select all that apply - 3)
A) Esophageal intubation
B) Leak around the endotracheal tube cuff
C) Increased fresh gas flow rate
D) Ventilator circuit obstruction
A) Esophageal intubation
B) Leak around the endotracheal tube cuff
D) Ventilator circuit obstruction
slide 13
What is the typical difference between PaCO2 and ETCO2 under normal conditions?
A) 2 mm Hg
B) 5 mm Hg
C) 10 mm Hg
D) 15 mm Hg
B) 5 mm Hg
slide 14
Which of the following conditions can increase the difference between PaCO2 and ETCO2 due to ventilation/perfusion (V/Q) mismatch?
A) Bronchospasm
B) Pulmonary embolism
C) Hyperventilation
D) High tidal volume
B) Pulmonary embolism
* also endobronchial intubation
slide 14
Which condition is most likely to cause difficulty in delivering alveolar gas to the sampling site, leading to an increased difference between PaCO2 and ETCO2?
A) Healthy adults with regular breathing patterns
B)Hyperventilating adults
C) Children with slow respiratory rates
D) COPD patients with severe bronchi collapse
D) COPD patients with severe bronchi collapse
Which of the following scenarios can cause an increased difference between PaCO2 and true ETCO2 (alveolar gas) due problems with capnography?
Select 2
A) Neonates and infants with rapid breathing
B) COPD with severe bronchi collapse
C) Calibration error in the capnograph
D) Slow response time relative to the breathing pattern
C) Calibration error in the capnograph
D) Slow response time relative to the breathing pattern
slide14
Identify the factors that can increase the difference between PaCO2 and measured ETCO2 due to issues with the capnograph: (Select all that apply - 2)
A) Properly calibrated equipment
B) Sampling catheter leaks
C) Slow response time
D) Accurate synchronization with breathing pattern
B) Sampling catheter leaks
C) Slow response time
- calibration errors, slow response time relative to breathing pattern
slide 14
Which non-invasive method can be used to monitor ETCO2 in spontaneously breathing patients using a dual-purpose device that delivers oxygen and samples exhaled air?
A) Endotracheal tube
B) Nasal Cannula
C) Laryngeal mask airway
D) Mechanical ventilator
B) Nasal Cannula
slide 15
Which device can be used to monitor ETCO2 in patients who require supplemental oxygen and is equipped with ports for a sampling line?
A) Simple Mask
B) Nasal Cannula
C) Endotracheal Tube
D) Venturi Mask
A) Simple Mask
slide 15
What is the primary principle behind the most common clinical measurement of ETCO2?
A) Colorimetric analysis
B) Infrared (IR) light absorption
C) X-ray imaging
D) Visual inspection of exhaled breath
B) Infrared (IR) light absorption
slide 16
In the context of IR light absorption techniques for ETCO2 measurement, what happens as the CO2 concentration in the sample increases?
A) More IR light reaches the detector
B) The sample becomes transparent
C) The sample’s temperature decreases
D) Less IR light reaches the detector
D) Less IR light reaches the detector
slide 16
What does a chemical indicator with a pH-sensitive paper showing a color change to yellow indicate during intubation?
A) Presence of CO2, indicating proper placement
B) No CO2 detected
C) Esophageal intubation
D) High levels of oxygen
A) Presence of CO2, indicating proper placement
limitation: can still show CO2 presence even in an esophageal intubation
slide 16
Which additional methods are recommended to accurately verify endotracheal tube placement beyond the use of a chemical indicator?
A) Checking the patient’s pulse
B) Listening for breath sounds and using X-ray imaging
C) Observing for chest rise
D) Using a thermometer
B) Listening for breath sounds and using X-ray imaging
slide 16
What is the acceptable accuracy range for CO2 readings in ETCO2 monitors as per standard requirements?
A) +/- 5% of the actual value
B) +/- 10% of the actual value
C) +/- 12% of the actual value
D) +/- 15% of the actual value
C) +/- 12% of the actual value
slide 17
Which of the following is a required feature for ETCO2 monitors to ensure patient safety?
A) A high oxygen alarm
B) An alarm for high inhaled and exhaled CO2 levels
C) A low temperature alarm
D) A heart rate monitor
B) An alarm for high inhaled and exhaled CO2 levels (rebreathing)
slide 17
Which substances’ interference must be disclosed by manufacturers of ETCO2 monitors? (Select all that apply - 3)
A) Ethanol
B) Acetone
C) Nitrogen
D) Halogenated volatiles
A) Ethanol
B) Acetone
D) Halogenated volatiles
slide 17
Which phase of the capnogram represents the expiratory upstroke where CO2 from the alveoli begins to reach the sensor?
A) Phase 0
B) Phase I
C) Phase II
D) Phase III
C) Phase II
slide 18
What does a sudden loss of exhaled CO2 in a capnogram typically suggest?
A) Increased pulmonary blood flow
B) Accidental extubation or disconnection
C) High cardiac output
D) Normal lung function
B) Accidental extubation or disconnection
slide 18
Which phase of the capnogram corresponds to the inspiratory phase?
A) Phase I
B) Phase II
C) Phase III
D) Phase 0
D) Phase 0
slide 18
What are the potential causes of a complete loss of exhaled CO2 on a capnogram?
A) Esophageal intubation
B) Accidental extubation
C) Apnea
D) Bronchospasm
E) All of the above
E) all of the above
* disconnection or failure of the sampling line/device
* cardiac arrest
slide 18
Identify the phases of the capnogram associated with exhalation: (Select all that apply - 3)
A) Phase 0
B) Phase I
C) Phase II
D) Phase III
B) Phase I
C) Phase II
D) Phase III
slide 18
During which phase of the capnogram does the anatomical dead space (DS) appear, where no gas exchange occurs?
A) Phase I
B) Phase II
C) Phase III
D) Phase 0
A) Phase I
slide 18
What is typically represented by Phase I on a normal capnograph?
A) CO2-rich alveolar gas
B) Expiration of anatomic dead space gas with essentially no CO2
C) Inspiratory phase
D) Plateau phase with CO2 from the alveolus
B) Expiration of anatomic dead space gas with essentially no CO2
slide 20
Which phase on the capnograph begins with the expiratory upstroke and involves the sampling of CO2-rich alveolar gas?
A) Phase I
B) Phase II
C) Phase III
D) Phase 0
B) Phase II
slide 20
What is the characteristic feature of Phase III on a capnograph?
A) Baseline with no CO2
B) Steep expiratory upstroke
C) Plateau phase, often with a slight increasing slope
D) Downstroke to baseline
C) Plateau phase, often with a slight increasing slope
- represents CO2 in the alveolus
- slight increase = ventilation heterogeneity (alveoli closing @ different times)
slide 21
Which phase on the capnograph is sometimes referred to as Phase IV and involves the inspiration of fresh gas?
A) Phase I
B) Phase II
C) Phase III
D) Phase 0
D) Phase 0
- remaining CO2 washed out
- downstroke returns to baseline
slide 21
Which characteristics are true for Phase I on a normal capnograph? (Select all that apply - 3)
A) Represents the baseline of CO2
B) Involves the exhalation of anatomic dead space air
C) Contains CO2-rich alveolar gas
D) Typically starts at 0 mm Hg unless rebreathing has occurred
A) Represents the baseline of CO2
B) Involves the exhalation of anatomic dead space air
D) Typically starts at 0 mm Hg unless rebreathing has occurred
slide 20
In which scenarios might the baseline of Phase I not start at 0 mm Hg on a capnograph? (Select all that apply - 2)
A) During normal breathing without rebreathing
B) When rebreathing CO2 is occurring
C) When the patient is hyperventilating
D) If the sampling device is malfunctioning
B) When rebreathing CO2 is occurring
D) If the sampling device is malfunctioning
slide 20
What is the occasional Phase IV’ in a capnograph characterized by?
A) A sharp downstroke in PCO2 at the beginning of Phase III
B) A sharp upstroke in PCO2 at the very end of Phase III
C) A flat plateau in PCO2 levels
D) A return to baseline CO2 levels
B) A sharp upstroke in PCO2 at the very end of Phase III
slide 22
What likely causes the sharp upstroke in PCO2 seen during the occasional Phase IV’ of a capnograph?
A) Sudden closure of all lung units
B) The closure of lung units with lower PCO2, allowing regions with higher PCO2 to contribute more to the exhaled gas sample
C) Complete alveolar ventilation
D) Increased respiratory rate
B) The closure of lung units with lower PCO2, allowing regions with higher PCO2 to contribute more to the exhaled gas sample
slide 22
In which patient populations is the occasional Phase IV’ more likely to be observed?
A) Patients with asthma
B) Pregnant and obese patients
C) Patients with COPD
D) Pediatric patients
B) Pregnant and obese patients
slide 22
What physiological changes contribute to the occurrence of the occasional Phase IV’ in pregnant and obese patients?
A) Increased functional residual capacity (FRC)
B) Increased lung capacity
C) Decreased functional residual capacity (FRC) and lung capacity
D) Enhanced alveolar ventilation
C) Decreased functional residual capacity (FRC) and lung capacity
slide 22
What does the alpha angle in capnography represent?
A) The separation between Phase I and Phase II
B) The separation between Phase II and Phase III
C) The separation between Phase III and Phase 0
D) The baseline of the capnogram
B) The separation between Phase II and Phase III
slide 23
What is the normal range for the alpha angle in capnography?
A) 80-90 degrees
B) 90-100 degrees
C) 100-110 degrees
D) 120-130 degrees
C) 100-110 degrees
slide 23
An increase in the alpha angle, often described as a “shark fin” pattern, is indicative of which condition?
A) Hyperventilation
B) Expiratory airflow obstruction
C) Normal lung function
D) Hypoventilation
B) Expiratory airflow obstruction
- alveoli close before completely emptying out
- Ex: COPD, bronchospasm, kinked ETT
slide 23
Which phase transition is indicated by the beta angle in capnography?
A) Phase I to Phase II
B) Phase II to Phase III
C) Phase III to Phase 0
D) Phase 0 to Phase I
C) Phase III to Phase 0
slide 23
Identify the scenarios that could lead to an increased beta angle on a capnogram: (Select all that apply - 3)
A) Malfunctioning inspiratory unidirectional valves
B) Rebreathing of CO2
C) Low tidal volume with rapid respiratory rate
D) Hypoventilation with deep breaths
A) Malfunctioning inspiratory unidirectional valves
B) Rebreathing of CO2
C) Low tidal volume with rapid respiratory rate
slide 23
What does this capnograph represent?
Mechanical Ventilation
slide 24
What does this capnograph represent?
Spontaneous Ventilation
slide 24
What is this capnograph showing?
Inadequate seal around ETT
* Beta angle opens & widens
* phase III cut short b/c the CO2 is going out and is lost around the seal
slide 25
What is the capnograph showing?
Faulty Inspiratory Valve
* thin disc gets stuck
* causes rebreathing of CO2
* Phase I starts @ 5-8mmHg instead of 0mmHg - there is NO return to baseline
* “the step up - indicative of faulty inspiratory valve
slide 26
What is this capnograph showing?
Sample Line Leak
- room air aspirated into broken sample line
- dilutes ETCO2 & decreases the value
- the “peak” is not phase IV’ - phase III would still get up to 40mmHg w/ phase IV’
slide 27
What is this capnograph showing?
Hyperventilation
- 3 capnographs that are decreasing in size
- trend is going down
- causes: decreased anesthesia, metabolic acidosis
slide 28
What is this capnograph showing?
Hypoventilation
- increased ETCO2
- trend is going up
- causes: hypoventilation, fever (increased production), narcotics
slide 29
What is this capnograph showing?
Airway obstruction
- phase II & III are connected
- alpha angle pretty much gone
- “shark fin” appearance
slide 30
What is this capnograph showing?
Cardiac Oscillations
- Seen in peds - the HR is close to trachea = vibrations
- @ the end of exhalation as flow decreases to 0 - beating of heart causes the lung regions to empty at different times
- usually goes away around 8-10yr old depending on size of kid
slide 31
What is this capnograph showing?
Re-breathing/Soda Lime Exhaustion
- phase 0 does not change - but the baseline gets higher and higher
- no step-up in phase 0
slide 32
What is this capnograph showing?
NMBD wearing off
* Curare Cleft - little dip @ the end of phase III * tells us if pt is coming back from paralysis * Can let them breathe on their own w/ PS or they need re-paralyzed
slide 33
What is this capnograph showing?
Over-breathing
- getting mechanical breath & taking spont. breath
- Can tell weaker vs. stronger spontaneous breaths
- Can allow pt to breathe spontaneously and titrate their narcotics to the RR (12-20)
slide 34
What is this capnograph showing?
Esophageal Intubation
- spontaneous looking waveform that disappears
- if they are mechanically ventilated & it goes away = accidental extubation/kinked tube/self-extubation
slide 35
