CRITICAL CARE AIR METHODS EXAM PRACTICE
QUESTIONS AND ANSWERS UPDATED |VERIFIED
2025/2026
LATEST VERSION !!!
pH and ETCO2 relationship
For every change in 10 mmHG of ETCO2, the pH will change 0.08 the
opposite direction
pH and Bicarb Relationship
For every change in 0.15 of pH, the bicarb will change 10 mmol/L the
same direction
pH and Potassium relationship
For every change in 0.10 of pH, the potassium will change 0.6 mEq's in
the opposite direction
CO2 and Potassium Relationship
For every change in 10 mmHg of Co2, the Potassium will change 0.5
mEq's the same direction
Normal PaO2
80-100 mmHg
pH
7.35-7.45
Co2
35-45
ABG
confirm vent settings with this 15 minutes after change in settings or
application
,Ventilator Pearls
Check Vt first, then the rate
Pressure Support Ventilation (PSV)
- mode of mechanical ventilation in which preset positive pressure is
delivered with spontaneous breaths to decrease work of breathing
- Patient determines Vt
- patient must be able to give breaths
"DOPE"
Dislodgement/ displacement
Obstruction
Pneumothorax
Equipment failure
Dislodged
Low pressure alarm
hose pulled out or ETT comes out
Obstructed
High pressure alarm
Kinked line or suction needed
Pneumothorax (vent alarm)
High pressure alarm
Equipment (vent alarm)
machine failure
dead batteries
Patient-ventilator dyssynchrony
,A mismatch between patient's ventilation needs and the assistance
delivered by the ventilator.
Causes increased pressure, tachycardia, hypoxia
ensure proper set up, pain relief, and sedation
pulse oximetry
Gold standard for measuring oxygenation
capnography
Gold standard for measuring ventilation
Hypoxic Respiratory Failure
ARDS, pneumonia, CHF
Inability to diffuse O2
PaO2 < 60mmHg
Increased PEEP and Fio2
treatment for hypoxic respiratory failure
Hypercarbic Respiratory Failure
CNS dysfunction
inability to remove Co2
evidenced by respiratory acidosis Co2>45
Increase Vt, then rate
treatment for hypercarbic respiratory failure
Asthma
-problem breathing out
- wheezing
- bronchspasms
, - flattened diaphragm on CXR
- respiratory acidosis
Asthma/ COPD treatment
bronchodilators
steroids
iv fluids
Increase I:E ratio giving more time for exhale
0 to low PEEP initially
increase Fio2
ketamine for sedation
COPD
problem breathing out
respiratory acidosis
flattened diaphragm in CXR, large chest cavity d/t air trapping
HCO3-
22-26 mEq/L
Indications for advanced airway
- cannot manage secretions
- GCS < 8
- insufficient ventilation effort
- Need increased FiO2
- Remove blood, secretions, infection
- pH < 7.2, cO2 > 55, PaO2 < 60
Pediatric indications for advanced airway
QUESTIONS AND ANSWERS UPDATED |VERIFIED
2025/2026
LATEST VERSION !!!
pH and ETCO2 relationship
For every change in 10 mmHG of ETCO2, the pH will change 0.08 the
opposite direction
pH and Bicarb Relationship
For every change in 0.15 of pH, the bicarb will change 10 mmol/L the
same direction
pH and Potassium relationship
For every change in 0.10 of pH, the potassium will change 0.6 mEq's in
the opposite direction
CO2 and Potassium Relationship
For every change in 10 mmHg of Co2, the Potassium will change 0.5
mEq's the same direction
Normal PaO2
80-100 mmHg
pH
7.35-7.45
Co2
35-45
ABG
confirm vent settings with this 15 minutes after change in settings or
application
,Ventilator Pearls
Check Vt first, then the rate
Pressure Support Ventilation (PSV)
- mode of mechanical ventilation in which preset positive pressure is
delivered with spontaneous breaths to decrease work of breathing
- Patient determines Vt
- patient must be able to give breaths
"DOPE"
Dislodgement/ displacement
Obstruction
Pneumothorax
Equipment failure
Dislodged
Low pressure alarm
hose pulled out or ETT comes out
Obstructed
High pressure alarm
Kinked line or suction needed
Pneumothorax (vent alarm)
High pressure alarm
Equipment (vent alarm)
machine failure
dead batteries
Patient-ventilator dyssynchrony
,A mismatch between patient's ventilation needs and the assistance
delivered by the ventilator.
Causes increased pressure, tachycardia, hypoxia
ensure proper set up, pain relief, and sedation
pulse oximetry
Gold standard for measuring oxygenation
capnography
Gold standard for measuring ventilation
Hypoxic Respiratory Failure
ARDS, pneumonia, CHF
Inability to diffuse O2
PaO2 < 60mmHg
Increased PEEP and Fio2
treatment for hypoxic respiratory failure
Hypercarbic Respiratory Failure
CNS dysfunction
inability to remove Co2
evidenced by respiratory acidosis Co2>45
Increase Vt, then rate
treatment for hypercarbic respiratory failure
Asthma
-problem breathing out
- wheezing
- bronchspasms
, - flattened diaphragm on CXR
- respiratory acidosis
Asthma/ COPD treatment
bronchodilators
steroids
iv fluids
Increase I:E ratio giving more time for exhale
0 to low PEEP initially
increase Fio2
ketamine for sedation
COPD
problem breathing out
respiratory acidosis
flattened diaphragm in CXR, large chest cavity d/t air trapping
HCO3-
22-26 mEq/L
Indications for advanced airway
- cannot manage secretions
- GCS < 8
- insufficient ventilation effort
- Need increased FiO2
- Remove blood, secretions, infection
- pH < 7.2, cO2 > 55, PaO2 < 60
Pediatric indications for advanced airway
