Respiratory Failure Flashcards
What is respiratory failure?
syndrome of inadequate gas exchange due to dysfunction of one or more components of the respiratory system
What failing parts of the body can cause respiratory failure?
- CNS/brainstem
- PNS
- NMJ
- diaphragm and thoracic muscles
- extra-thoracic muscles
- airways
- alveolar-capillary disease
- circulation
What is the biggest risk factor of chronic respiratory failure for men?
smoking
What is the biggest risk factor of chronic respiratory failure for women?
household air pollution from solid fuels
What is the prevalence of acute respiratory failure?
6-700 people/year
What factors can increase the mortality of acute respiratory failure?
- severity
- age
What possible diseases are classed as acute respiratory failure?
- infection
- aspiration
- primary graft dysfunction
- trauma
- pancreatitis
- sepsis
- myasthenia/GBS
What possible diseases are classed as chronic respiratory failure?
- COPD
- Lung fibrosis
- CF
- lobectomy
- muscular dystrophy
What are examples of acute on chronic respiratory failure?
- Infective exacerbation (COPD, CF)
- Myasthenic crises
- Post-operative complications
What happens in type 1 (hypoxemic) respiratory failure?
PaO2 < 60 failure of oxygen exchange - increased shunt fraction (QS/QT) - alveolar flooding - refractory to supplemental oxygen
What can cause type 1 respiratory failure?
- collapse
- aspiration
- pulmonary oedema
- fibrosis
- pulmonary embolism
- pulmonary hypertension
What happens in type 2 (hypercapnic) respiratory failure?
PaCO2 > 45
failure to exchange or remove carbon dioxide
- decreased alveolar minute ventilation
- dead space ventilation
What can cause type 2 respiratory failure?
- CNS/PNS
- muscle failure
- airway obstruction
- chest wall deformities
- reduced minute ventilation
What happens in type 3 (perioperative) respiratory failure?
- increased atelectasis (airway collapse) due to low functional residual capacity
- abnormal abdominal wall mechanics (limiting chest movement)
- hypoxaemia OR hypercapnia
How do you prevent type 3 respiratory failure?
- anethetic or operative technique
- posture
- incentive spirometry
- analgesia
- efforts to lower intra-abdominal pressure
What happens in type 4 (shock) respiratory failure?
- poor lung perfusion
patients that are intubated and ventilated during shock (septic, cardiogenic, nuerologic)
How do you prevent type 4 respiratory failure?
optimise ventilation to improve gas exchange and to unload the respiratory muscles, lowering oxygen consumption
What are the effects of ventilation on the heart?
reduced afterload (good for the LV) increased preload (bad for the RV)
What are the risk factors for chronic respiratory failure?
- COPD
- pollution
- recurrent pneumonia
- CF
- pulmonary fibrosis
- neuromuscular diseases
What are the risk factors for acute respiratory failure?
- infection (viral and bacterial)
- aspiration
- trauma
- pancreatitis
- transfusion
What are the 5 main origins of shortness of breath?
- lower respiratory tract infections
- aspiration
- trauma
- pulmonary vascular disease
- extrapulmonary: pancreatitis; new medications
What form of lower respiratory tract infection can cause shortness of breath?
- viral
- bacterial
What form of trauma can cause shortness of breath?
transfusion
What form of pulmonary vascular disease can cause shortness of breath?
- pulmonary embolus
- haemoptysis
When is ventilation used?
Type IV respiratory shock
What are the pulmonary causes of ARDS?
- aspiration
- trauma
- burns (inhalation)
- surgery
- drug toxicity
- infection
What are the extra-pulmonary causes of ARDS?
- trauma
- pancreatitis
- burns
- transfusion
- surgery
- BM transplant
- drug toxicity
what do the pulmonary causes of ARDS tend to effect?
- the alveoli
what do the extra-pulmonary causes of ARDS tend to effect?
- systemic
- cytokine release
What cytokines signal the inflammation pathway in the alveoli?
TNF-a and IL-8