Blood-Gas Analysis Flashcards
Respiratory acidosis and alkalosis
PaCO2, HCO3-
Acidosis: both increased
Alkalosis: both decreased
Metabolic acidosis and alkalosis
PaCO2, HCO3-
Acidosis: both decreased
Alkalosis: both increased
Explain Base Excess
- refers to an excess or deficit in the amount of base present in the blood
- defines the metabolic component of acid-base disturbances
What is indicated by a positive BE?
By a negative BE?
Pos: metabolic alkalosis
Neg: metabolic acidosis
What is the normal value for PaO2/FiO2 ratio?
> 500 mmHg
What are the 5 causes of hypoxemia?
- Low FiO2
- Hypoventilation
- Diffusion impairment
- V/Q mismatch
- right to left shunt
What can cause V/Q mismatch?
Atelectasis: collapse lung fields
- blood in lungs do not oxygenate
Lung diseases:
- asthma, pulmonary edema, ARDS, pneumonia
What is the normal range for PaCO2?
35-45 mmHg
What is IPPV?
- Intermittent Positive Pressure Ventilation
- positive pressure is maintained only during inspiration
What is IMV?
- Intermittent Mandatory Ventilation
- operator sets a predetermined number of positive breaths, but patient can also breath freely between mechanical breaths
What is CPAP?
- Continuous Positive Airway Pressure
- spontaneous breathing with positive pressure during both inspiratory and expiratory phases
What is PIP?
- Peak Inspiratory Pressure
- highest pressure during inspiration
- this pressure inflates alveoli, opens alectasis, or causes barotrauma
What is PEEP?
- Positive End Expiratory Pressure
- positive pressure that is maintained during expiration
- this pressure keeps the alveoli open
What are possible side effects of mechanical ventilation?
- hypotension
- pneumothorax
- lung injury
How is manual ventilation performed?
- close the pop-off valve
- squeeze reservoir bag until desired pressure
- release bag so patient can expire
- open pop-off valve to avoid over-inflation
