PFTs & ABGs Flashcards
(79 cards)
Describes amt of O2 bound to hemoglobin in arterial blood
Normal value =
SaO2 (saturation)
Normal = 95-100%
Amt of O2 dissolved in arterial blood plasma
Partial pressure of O2 in arterial blood
Normal value =
PaO2
Normal = 80-100mmHg
Blood oxygen saturation level
Normal =
Mild respiratory disease =
Supplementary O2 should be used if falls below ________
SpO2
Normal = 94-99%
Mild respiratory disease > 90%
Supplemental O2 if falls below 90%
2 conditions of respiratory failure
Hypercarbia
Hypoxemia
What is hypercarbia?
Condition of abnormally elevated levels of CO2 levels in blood
Ex: COPD with acute exacerbation
What is hypoxemia?
Low O2 in blood
Ex: severe bilateral pneumonia
What type of receptor detects too much O2 or too little CO2?
Chemoreceptors (detect changes in chemical concentrations)
Where does O2 diffuse from alveoli to arterial blood and CO2 exits?
Alveolar-Capillary Membrane (AC membrane)
What is the partial pressure of CO2 called?
(Ventilation & ________)
Normal =
PaCO2 (in artery)
“Little a = artery, big A = alveolar”
Normal = 35-45 mmHg
If bulk of O2 is carried bound to hemoglobin, _________ (larger/smaller) amount is what is dissolved in plasma.
What is this called?
Smaller
PaO2
Patient not ventilating enough- not blowing off enough CO2
Respiratory acidosis (CO2 goes up, pH goes down)
Pt hyperventilating because of pain or anxiety, blowing off too much CO2
Respiratory alkalosis (pH goes up)
Too little blood =
Too little oxygen =
Hypoxemia
Hypoxia
Carotid arteries and aorta are ___________receptors that respond to changes in blood __________ in normal breathing
Chemoreceptors
Blood chemicals
Signals are sent to ________ as PaCO2 and PaO2 change in normal breathing
Medulla
Medulla sends signal to respiratory muscles to contract with the _________ nerve in normal breathing
C3-5 phrenic nerve (innervated diaphragm)
As thorax expands, the diaphragm ___________ in normal breathing
Contracts
Basic pulmonary abnormalities of ventilation (2)
Restrictive defect (neuromuscular, morbid obesity, circumferential burns) Obstructive defect (asthma, copd)
Basic pulmonary abnormalities of oxygenation (2)
Diffusion deficit (pulmonary fibrosis- idiopathic) Shunt (atelectasis, ARDS)
Indications for PFT (5)
- Measuring lung volumes/capacities/flows (vs baseline and normal values)
- Quantify level of lung dysfunction
- Pt response to treatment protocols
- Pre-op screening
- Disability evaluation
Lung volumes and capacities are a measure of A/W and lung ___________
RESTRICTION
Two or more volumes = capacity
What are the 4 volume measures?
- Tidal volume (VT)
- Inspiratory reserve volume (IRV)
- Expiratory reserve volume (ERV)
- Residual volume (RV)
What is tidal volume
normal breath = 500 mls
What is inspiratory reserve volume
Volume above normal inhalation = approx 3 L