Critical Care, TARMS Flashcards
What are the different levels of care provided by critical care?
Level 0 - needs can be met through normal ward
Level 1 - at risk of deteriorating; needs met with support from critical care team
Level 2 - patients requiring more detailed observation/interventions; a single failing organ system; post-operative care
Level 3 - advanced respiratory support; support of at least 2 organ systems; support for multi-organ failure
What are type 1 and type 2 respiratory failure?
Type 1 = Hypoxaemia
- PO2 < 8kPa on air
- PCO2 < 6kPa
Type 2 = Hypoxaemia + hypercapnia
- PO2 < 8kPa on air
- PCO2 > 6kPa
What causes a type 1 respiratory failure?
V/Q mismatch
- Reduced ventilation but normal perfusion e.g. pulmonary oedema, bronchoconstriction
- Reduced perfusion but normal ventilation e.g. PE
Name 4 categories of causes of type 2 respiratory failure
- Increased resistance due to airway obstruction e.g. COPD
- Reduced compliance of lung tissue/chest wall e.g. rib fractures, obesity
- Reduced strength of respiratory muscles e.g. MND, Guillan-Barré
- Drugs acting on respiratory centre e.g. opiates
What are the indications for a CPAP machine?
Type 1 respiratory failure
- Pulmonary oedema
- Fluid overload
- Atelectasis
- Pneumonia
Severe obstructive sleep apnoea
What does CPAP do?
A fixed low positive pressure is delivered throughout inspiration and expiration
It assists spontaneous ventilation
It splints the airway open and so prevents airway collapse and loss of lung volume
What complications can arise from CPAP?
Pneumothorax
Hypotension
What does BiPAP stand for?
Biphasic Positive Airway Pressure
How does BiPAP work?
Delivers positive pressure throughout inspiration and expiration
The inspiratory positive airways pressure is higher than the expiratory positive airways pressure so ventilation is provided by iPAP
ePAP recruits collapsed alveoli (keeps them open for longer) for better gas exchange and removal of exhaled gas
What does positive airway pressure mean?
The pressure outside the lungs is greater than the pressure inside the lungs, which results in air being forced into the lungs (requiring less respiratory effort) and increasing the forced residual capacity of the lungs
What part of breathing requires the most energy?
Normally, bronchioles and alveoli collapse at the end of expiration
Overcoming the pressures required to re-expand collapsed parts of the lungs requires the most energy
What are the indications for BiPAP?
- Type 2 respiratory failure
- COPD with a respiratory acidosis
- Secondary to chest wall deformity
- Secondary to neuromuscular disease - Weaning of tracheal intubation
What are some contraindications to CPAP/BiPAP?
Definite contraindications:
- Facial burns/trauma
- Vomiting/excess secretions - risk of aspiration
Potential contraindications:
- Confusion/agitation
- Impaired consciousness
- Bowel obstruction
- Recent facial/upper airway surgery
- Undrained pneumothorax
What happens if the iPAP is too high on a BiPAP machine?
Hypotension due to reduced venous return
Can cause the mask to leak
Can lead to stomach inflation with risk of vomiting and aspiration
Define death
Irreversible loss of capacity for consciousness combined with irreversible loss of capacity to breathe
Where is the brainstem and what is it comprised of?
Brainstem is in the posterior part of the brain and is continuous with the spinal cord
It includes the midbrain, the pons and the medulla oblongata