Pulmonary II : Acute Respiratory Failure Flashcards
What is Acute Respitory Failure
> Inability of Respitory System to Meet Demands of :
- Oxygen
- Ventilation
- OR Metabolic Requirement (CO2 )
- CO2 high –> Fast RR
- CO2 Low —– Slow RR
Two Types of Acute Respitory Failure
**Type 1 Hypoxic Failure
Type 2 Hypercapnic Failure
W/WO Hypoxemic RR Failure
Type 1 Respitory Failure
> **Hypoxic Failure **
> **Oxygenatio Failure **
- PaO2 <60% mmHG Based on ABG
PaO2 = (partial arterial pressure )
> Hallart of Type 1 = Hypoxemia >
Type 2
Hypercapnic RF
- Ventilatio Failure
- W/WO Hypoxemic RF (can be both)
- PaCO2 > 50 mmHg
Hypoxemic Respiratory Failure
**Mechanism of Hypoxemia **
x 5
- Inadequate O2 at Alveolar Level (PAO2) **
- Alveolar Hypoventilation or Decreased FiO2
2. Ventilation Perfusion Abnormalities **
- Monst common
3.** Intracardiac /Intrapulmonary **
- Intracardiac —> PFO (R and Left )
- Intrapulmonary —- > Pulmonary AV malformation - **Diffusion Abnormality (Determin GAS EXchange )
- Low Pulmonary Arterial Oxygenatio
- Causes “
CNS > PNS > Thoracic bellow > Upper Airways > Lungs
Tissue Oxygenation
O2 Understanding
Required for
> Metabolic Processes and
> Cellular Functions
Extraction O2 from
Environmenta Air
GAses exchange
Each HAS a
> Partial Pressure When Mixed
Compnesation of
Environmental AIR
formula ?
N: Nitro 78%
O2 : 21%
Ar: 1%
Atmosphere Pressure
760mmHg
Alviolar Partial Pressure
PAO2
>** Driving Force for O2 diffusion **
- O2 moves alveolar membranes >
Pulmonary Capilary >
Arterila blood flow and Erythrocytes
Peripheral tissue s
**> Quinatifying O diffusion gradient **
- A-a gradient = PAO2 (alveoli) - PaO2
-Larger gradient indicates pathology hindering transfer of O2 to capillary
Supplemental Oxygen
21% value
FiO2 % on RA
1L /O2 increases inspires O2 by 4% /0.04
2 x 4 = 8
Bohr Effect
O2 association with HgB
Inversely Related to Acidity and PaO2 concentration
Left Shift
> Greater Affinity for O2
Alkalemia
Hypothermia
Hypometabolism
Abnormal HgB
Right Curve shift
Lesser Affinity for O 2
> Acidemia
> Hyperthermia
> Hypermetabolism
>Chronic Hypoxemia
> Hypercapnia
Acute Respitory Failure - Type 1
- Hallmark : Hypoxemia
- Hypoxemia Assessment on ABG
*Partial Pressure Of oxygen (PaO2 ) - **Approximated PaO2 = FiO2 x 5 **
EX: Vented patient with FiO2 40%
Should Have PaO2 of approximatly 200 (40 x 5)
Type 1 ARF
Oxygenation Saturation (SaO2)
- Reflection of oxyhemoglobin
*HgB bound with O2 - **Anemia does not affect SaO2 **
- If pt has FiO2 100% and HgB 6.5 ( their O2 NOT 100% )
**CO Poisoning **> Carbon Monoxide Poisoning
> Not always accurate assessment
> **Falsely Hight SaO2 level low PaO2 **
> Carbon monoxide does
Acute Respitory Failure - Type 2
Hallamark : Hypecapnea (PaCO2 >50)
- AKA Acute Ventilatory Failure
- Acute Respitory Acidosis
- pH <7.35
- PaCO2 >50
Type 2 ARF
Causes
- Increase CO2 Production
*Decreased Total tidal Ventilation - Increased dead space Ventilation
Typ 2
Increase CO2
Inrease Metabolic Demands
> Exercise
> Fever
Sepsis
Burns
Trauma
Excessive carbohydrate incatke
Hyperthyoridism
**Determining Cause of dead Space **
A-a Gradient ** ***
> normal 5 to 10 mmHg
> Increase A-a (10 to 15) Parenchymal Lungs process > Alveoli Hyperventilation
CNS Depressent
Narcontic
Sedation
Neuromuscular
Transimisison disorders
Myasthenia Gravis
Abnormal Respiratory Mechanics
Airlow obstruction or chest wall
*** Hallmark Inadequate VentilatiOn **
Elevated PaCO2 >50 w/wo Hypoxemia
**Sign and Symptosm **
Abnormal Respitory Rate
Irregular Pattern
Gasping Ventilation
Nasal flaring
Accessory muschle use
Respiratory encephalopathy (lethargy Coma tremors )
