Respiratory failure Flashcards
Define type 1 respiratory failure
PaO2 <8KPa and PaCO2 <6KPa (normal-low)
Define type 2 respiratory failure
PaO2 <8KPa and PaCO2 >6KPa
What is the physiological cause of type 1 failure?
V/Q mismatch and diffusion failure
Two causes of type 1 failure?
PE Asthma Pneumothorax Pulmonary hypertension Collapse= atelectasis
What is the physiological cause of type 2 failure?
Alveolar hypoventilation ( \+- V/Q mismatch)
Three causes of type 2 failure?
COPD asthma bronchiectasis Fibrosis NM disease- GBS, myasthenia gravis Reduced resp drive: trauma, CNS sedation
One cause of diffusion failure causing type 1 resp failure?
fluid- pulmonary oedema, pneumonia, blood, infarction
fibrosis
Two causes of obstructive lung disease?
asthma
COPD
bronchiectasis
Two causes of restrictive lung disease?
fibrosis
NM disease- GBM, MG
reduced resp drive: trauma, tumour, CNS sedation
Two signs/symptoms of hypoxia?
Dyspnoea Confusion Cyanosis Agitation Polycythaemia Cor pulmonare
Two signs/symptoms of hypercapnoea?
headache bounding pulse flap confusion- coma flushing and peripheral vasodilation
Treatment of type 1 failure?
Give O 2 to maintain SpO 2 94-98%
Assisted ventilation if PaO 2 <8KPa despite 60% O 2
Treatment of type 2 failure?
Oxygen therapy
NIV
Respiratory stimulant
What percentage of O2 for type 2 failure?
24%
SpO2 percentage in type 2 failure?
88-92%
When would you intervene with NIV in type 2 respiratory failure?
If PaCO 2 ↑>1.5KPa and pt. still hypoxic
Target oxygen percentage in patients with type 1 resp failure?
94-98% for most patients
Someone has metabolic acidosis with raised anion gap. What could be happening?
renal failure, ketoacidosis, lactic acidosis, toxins, therefore measure these
Patient with metabolic acidosis but normal anion gap. What could be a cause?
diarrhoea- excess HCO3- loss
renal tubular acidosis
What is the normal anion gap?
8-16 mmol/L
Two causes of respiratory acidosis?
Airway obstruction- COPD, asthma
CNS depression
Obstructive sleep apnoea
Two causes of resp alkalosis?
CNS stimulation: pain, fea, anxiety, brain trauma
Drugs
Pregnancy
Hypoxia
Two causes of metabolic alkalosis?
Vomiting
Diarrhoea
Renal loss of H+- cirrhosis, heart failure, nephrotic syndrome
Two causes of metabolic acidosis?
DKA Isoniazid Ethanol intoxication Uraemia Lactic acidosis- tissue ischaemia
