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 parts of the nervous system are in the respiratory system?
- CNS/Brainstem
- Peripheral nervous system
- Neuro-muscular junction (e.g. myasthenia gravis)
What parts of the respiratory muscle are in the respiratory system?
•Diaphragm & thoracic muscles
•Extra-thoracic muscles
e.g. msucular underlying disease
What parts of the pulmonary are in the respiratory system?
- Airway disease
- Alveolar-capillary e.g. fibrosis or vascular disease
- Circulation e.g. pulmonary hypertension
Why is chronic respiratory disease important?
Chronic respiratory disease 3rd leading cause of death* (2017) 39.8% rise from 1990
What is the biggest risk factor for males and females for chronic respiratory disease?
- Males: Smoking biggest risk factor
- Women: Household air pollution from solid fuels
How expensive is it to treat chronic respiratory disease?
- Costs: EU 380m Euro’s annually (2019) care for chronic respiratory disorders
- Accounts for: Inpatient care, lost productivity
- Despite extensive costs: limited granular data
How has chronic respiratory disease change from 1990 to 2017?
From 1990 to 2017, the prevalence, mortality, and DALY rates per 100k dropped by 14·3%, 42·6%, and 38·2%,
Why is acute respiratory disease hard to monitor?
- Present in different ways and different times
- Heterogenous disease, down to pneumonia or COPD or cystic fibrosis or pulmonary hypertension
- So look at acute respiratory distress syndrome (ARDS)
How common is ARDS?
-Prevalence: 6-7 per 100,000 = 6-700 people/yr in UK
-30 to 40% Mortality (ALIEN/Esteban)
35, 40 and 46% (Severity dependent. Bellani)
-Severity and advance age
-> increase mortality
How do you classify ARDS?
- Timing
- Chest imaging
- Origin of oedema
- Oxygenation / PF ratio
What is needed to classify acute?
- Pulmonary: Infection, aspiration, Primary graft dysfunction (Lung Tx)
- Extra-pulmonary: Trauma, pancreatitis, sepsis,
- Neuro-muscular: Myasthenia/GBS
What is needed to classify chronic?
- Pulmonary/Airways: COPD, Lung fibrosis, CF, lobectomy
2. Musculoskeletal: Muscular dystrophy
What is needed to classify acute and chronic?
- Infective exacerbation: COPD, CF
- Myasthenic crises
3 Post operative
What is Type 1 respiratory failure?
- Failure of oxygen exchange
- Increased shunt fraction (Q S /QT )
- Due to alveolar flooding (usually heart failure)
- Hypoxemia refractory to supplemental oxygen
What is another word for Type 1 respiratory failure?
Hypoxemic (PaO2 <60 at sea level)
Why might you have Type 1 respiratory failure?
- Collapse (of lobe)
- Aspiration
- Pulmonary oedema
- Fibrosis
- Pulmonary embolism
- Pulmonary hypertension
What is Type 2 respiratory failure?
-Failure to
exchange or remove carbon dioxide
-Decreased alveolar minute ventilation (V A )
-Dead space ventilation
What is another word for Type 2 respiratory failure?
Hypercapnic (PaCO2 >45)
Why might you have Type 2 respiratory failure?
- Nervous system disease
- Neuromuscular disease
- Muscle failure
- Airway obstruction e.g. COPD
- Chest wall deformity
- Muscle weak so cannot drive adequate tidal volumes or respiratory rates as very tired or muscle fatigue or progressive weakness
What is type 3 respiratory failure?
- Perioperative respiratory
Failure - Increased atelectasis due to low functional residual capacity
(FRC) with abnormal abdominal wall mechanics - Hypoxaemia or hypercapnoea
How do you prevent type 3 respiratory failure?
Prevention:
- anesthetic or operative technique
- posture
- incentive spirometry
- analgesia
- attempts to lower intra- abdominal pressure
What is type 4 respiratory failure?
- Shock
- patients who are intubated and ventilated
- During shock (Septic/cardiogenic/neurologic)
- gas doesn’t meet blood, poor perfusion of lungs
How do you get positive pressure ventilation?
using ventilator
How does ventilation affect the heart?
- Push air into chest get positive pressure
1. Good for LV as reduces afterload so stress on heart muscle reduced, so work heart muscle has to do is reduced as pressure differential between LV and thorax is lower
2. Bad for RV as increased pre-load
What are the chronic risk factors?
- COPD
- Pollution
- Recurrent pneumonia
- Cystic fibrosis
- Pulmonary fibrosis
- Neuro-muscular diseases