Respiratory Failure Flashcards
Describe type 1 respiratory faiure
Low PaO2 (<8.0kPa) Normal/low PaCO2 (4.6-6.0kPa)
Describe type 2 respiratory (ventilatory) failure
Low PaO2 (<8.0kPa) High PaCO2 (>6.0kPa)
What are the symptoms of a high arterial PaCO2?
Headache Tachycardia Bounding pulse CO2 retention flap Papilloedema Acidosis
How can metabolic and respiratory causes of acidosis be distinguished?
High PaCO2 = respiratory
Low H2CO3 = metabolic
How can acute respiratory acidosis be distinguished from chronic respiratory acidosis?
Metabolic compensation takes a few days, level of H2CO3 is a marker of timescale
What are the common causes of Type 1 RF?
Diseases of the lung parenchyma
- Pulmonary oedema
- Pneumonia
- PE
- COPD
- ARDS
- Asthma (initially)
What are the common causes of Type II RF?
Insufficient alveolar ventilation to excrete volume of CO2
-Pulmonary disease (asthma, COPD, PF, OSA)
-Reduced resp drive (CNS pathology, sedative drugs)
-Thoracic wall disease (rib fracture, kyphoscoliosis, flail chest)
Neuromusclar disease (MG, Guillan-Barre, cord lesions, poliomyelitis)
What are the features of an acidosis?
Kussmaul resp - air hunger, deep & laboured breathing
Cardiovascular dysfunction
K abnormalities - hypo if renal funcn good, hyper if impaired
Cerebral dysfunction - confusion/coma
Peripheral vasodilation/increased permeability - oedema
What investigations are appropriate in acute ventilatory failure?
FBC, U&E, CRP
ABG
CXR
Sputum/blood cultures (if febrile)
How should T1 RF be managed?
Treat underlying cause
High flow O2 (60%) via face mask
Assisted ventilation if PaO2 <8kPa
How should T2 RF be managed?
Resp centre reliant on hypoxic drive
O2 therapy given w/ care (24% O2)
What is the effect of chest wall/spinal deformity on respiratory function?
Restrictive conditions
- Decreased lung volume
- Increased work of breathing
- Inadequate ventilation/oxygenation
