Acute Respiratory Failure/ Acute Respiratory Distress Syndrome (ARDS) Flashcards
FiO2
Fraction of inspired oxygen (as percentage %).
PaO2
Partial Pressure of Arterial Oxygen (in mmHg)
- PaO2 stands for partial pressure of oxygen in arterial blood. It is a measure of the pressure exerted by oxygen molecules dissolved in the blood. PaO2 levels are an important indicator of how well the lungs are able to oxygenate the blood.
hypoxemia
decrease in oxygen tension in the arterial blood
- decreased PaO2
hypoxia
decrease in oxygen supply to the tissues and cells
acute lung injury
an umbrella term for hypoxemic respiratory failure; equivalent to mild acute respiratory distress syndrome (ARDS)
acute respiratory distress syndrome (ARDS):
nonspecific pulmonary response to a variety of pulmonary and nonpulmonary insults to the lung; characterized by interstitial infiltrates, alveolar hemorrhage, atelectasis, refractory hypoxemia, and, with the exception of some patients with coronavirus disease 2019 (COVID-19) and ARDS, decreased compliance
positive end-expiratory pressure (PEEP):
positive pressure maintained at the end of exhalation (instead of a normal zero pressure) to increase functional residual capacity (FRC) and open collapsed alveoli
Tidal Volume (Vt)
Volume of air inspired with each breath (in mL), individualized in mechanical ventilation.
Acute Respiratory Failure
- Acute disease process or mechanism that causes decreased serum O2 levels in blood.
- Pt is hypoxemic from:
— Failure to Ventilate ~ circulation of O2 adequate, air movement compromised
— Failure to Oxygenate ~ air movement adequate, O2 circulation (delivery) compromised.
— Combination of both
Acute Respiratory Failure CAUSES
- Ventilatory failure:
— Impaired CNS function
— Neuromuscular dysfunction
— Musculoskeletal dysfunction
— Pulmonary dysfunction
— Post- effects of above - Oxygenation failure:
— Pneumonia
— ARDS
— HF
— COPD
— PE
— Restrictive lung disease
Acute Respiratory Failure S/S
Early Signs:
- Restlessness
- Fatigue
- HA
- Dyspnea
- Tachycardia
- Increased BP
Acute Respiratory Failure S/S As hypoxemia progresses:
- Confusion
- Lethargy
- Tachycardia
- Central cyanosis (circumoral)
- Diaphoresis
- Respiratory arrest!
Acute Respiratory Failure 2
- Decreased PaO2 (arterial oxygenation <60 mmHg, oxygenation failure)
- ~and~
- Increased PaCo2 arterial carbon dioxide >45mmHg with arterial Ph <7.35
- Management: ET intubation & mechanical vent
Acute resp failure recap
- Pt is hypoxemic & Co2 retained
— From ventilatory failure (decreased air movement)
— Oxygenation failure (gas exchange)
— Combo of both ventilator & oxygenation failure - Arterial carbon dioxide >45 mm Hg with Arterial ph <7.35 (Resp. acidosis)
— s/s may occur in seconds or over hrs- depending on pt.
— If acidic (increased K); s/s hyperkalemia
Acute Respiratory Failure Treatment
- Correct the underlying cause and restore adequate gas exchange
- Mechanical ventilators may be required to maintain adequate ventilation/oxygenation while the underlying issue is being resolved
ARDS Acute Respiratory Distress Syndrome
- Inflammation triggers release of cellular and chemical mediators that cause damage to alveolar capillary membrane and other structural lung damage
— Alveoli collapse
— Small airways narrowed
— Decreases lung compliance - Severe inflammatory process
- causing diffuse alveolar damage that results in:
— sudden and progressive pulmonary edema
— increasing bilateral infiltrates on CXR
— hypoxemia unresponsive to supplemental oxygen
ARDS Acute Respiratory Distress Syndrome S/S
- tachycardia
- Dyspnea
- Retractions
- Hypoxia
- tachypnea
- Decreased pulmonary compliance
- Decreased PO2
- pt not getting better even with increased FiO2
- Rapid onset of severe dyspnea
- Arterial hypoxemia (that does not respond to supplemental O2)
- CXR- shows bilat infiltrates that quickly worsen
— increased alveolar dead space (ventilation to alveoli occur but poor perfusion) and decreased pulmonary compliance (“stiff lungs” difficult to ventilate)
Prone positioning
ROTO-PRONE
