Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
2 main types of respiratory failure
|
hypoxemic - inadequate O2 delivery
hypercapnic - respiratory acidosis |
|
|
Cause of hypoxemic failure
|
lung structure
|
|
|
Cause of hypercapnic failure
|
ventilation failure
|
|
|
5 physiological causes of hypoxemic failure (oxygen in blood)
|
dec PiO2
Dec Va V/Q mismatch R->L shunt diffusion limitation |
|
|
Most common presentation of dec PiO2
|
high altitude (plane travel)
|
|
|
Which is corrected by supplemental O2, V/Q mismatch or shunt?
|
V/Q mismatch
|
|
|
Underlying problem with diffusion limitation
|
inc transit time (like during exercise), so hypoxemia only occurs during exercise
-think pulmonary fibrosis |
|
|
Alveolar ventilation equation
|
=minute ventilation - dead space ventilation
OR =minute ventilation(1-dead space vent/tidal volume) |
|
|
Underlying physiology with hypercapnic failure
|
produce more CO2 or clearing out less
|
|
|
2 normal or inc causes of minute ventilation
|
Inc Ve secondary to inc VCO2
inc Ve secondary to inc Vd/Vt (PE, emphysema) |
|
|
Causes of dec respiratory drive
|
central drive (narcotic)
nerve conduction neuromuscular changes chest wall problems lung disease (COPD) Upper airway obstruction |
|
|
order of blood gas discussion
|
pH/pCO2/pO2/HCO3
|
|
|
Describe findings of pH, pCO2, HCO3 in acute respiratory failure.
|
pH <7.4, pCO2 elevated, HCO3 close to normal
|
|
|
Describe findings of pH, pCO2, HCO3 in compensated respiratory failure.
|
closer to normal pH, higher pCO2, high HCO3
|
|
|
Describe findings of pH, pCO2, HCO3 in acute and chronic respiratory failure.
|
low pH, high pCO2, elevated HCO3
|
|
|
In severe COPD pts, why is 100% O2 a problem in some?
|
too much O2, suppresses respiratory drive bc of shift in carotid body receptors to O2 sensors rather than CO2 sensors like normal.
Should keep levels in low 90s to keep pts stable |
|
|
Major etiology of respiratory muscle weakness
|
deconditioning (malnutrition, immobility, long-duration mech ventilation)
|
|
|
Clinical signs of respiratory muscle weakness
|
tachypnea
dec VC dec maximum inspiratory force ineffective cough hypercapnea is more of a late sign. |
|
|
Hypercapnic failure tx
|
dx and treat underlying cause
respiratory stim assist devices threshold for trach intubation and + pressure vent. Mech ventilation techniques |
|
|
4 main assist devices
|
negative pressure (iron lung, Cuirass ventilator)
Nasal/face mask CPAP Cycled CPAP (BiPAP) Positive pressure ventilation (normal mech vent today) |
|
|
Which component of mechanical ventilation occurs largely passively?
|
expiration
|
|
|
PEEP (Positive End Expiratory Pressure) is mainly for what purpose?
|
keeps alveoli open, encourages gas exchange
|
|
|
What is controlled with mechanical ventilation?
|
volume, pressure, pt regulated (can)
Can have hybrids as well -SIMV/P support -PRVC |
|
|
Adverse effects of PEEP
|
barotrauma
dec venous return -> dec CO |
|
|
Tx for mech ventilatory for hypoxemic resp failure
|
add FIO2, PEEP, inc inspiration:expiration ratio
|
