L3 ILP 1: Respiratory Failure Flashcards
What is hypoxaemia?
Inadequate oxygenation of blood PaO2 < 80mmHg
- Partial pressure of O2
PaO2 =< 60mmHg = SEVERE hypoxaemia
- May be acute or chronic
What are 6 pathological basis for hypoxaemia?
- V/Q mismatch (most common)
- Hypoventilation
- Diffusion limitation across blood-gas membrane
- ↓ FiO2 (eg, high altitude)
- Mixed causes
- Imbalance between O2 consumption & delivery
What are 5 basis for hypoxaemia?
What is hypoxia?
O2 delivery to tissues is inadequate to meet metabolic needs
What are 4 causes of hypoxia (results from)?
- Hypoxaemia- “next stage”
- ↓ cardiac output- Heart is not pumped blood (O2) out to the extremities
- ↓ Haemoglobin- No vehicle for O2 to bind to
- Increase Metabolic rate (eg burns)
What is hypercapnia?
PaCO2 >= 50mmHg (normal = 35-45mmHg)
What are 3 major clinical signs of respiratory distress?
- Respiratory compensation
- Increased sympathetic tone
- End-organ hypoxia
What are 4 clinical signs about respiratory compensation for respiratory distress?
What are 3 clinical signs about increased sympathetic tone for respiratory distress?
- Increased HR
- Increased BP
- Sweating (diaphoresis)
What are 5 clinical signs about end-organ hypoxia for respiratory distress?
- Altered mental status (Brain function)
- Confusion
- Aggression
- ↓awareness & ↓alertness
- Fitting
- ECG changes
- ST depression
- Ventricular ectopic beats
- Desaturation
- Cyanosis (Blueish tinge)
- Late signs
- Bradycardia
- Hypotension
What is respiratory failure?
“When the respiratory system is unable to provide adequate gas exchange for metabolic requirements”
What are the 2 types of respiratory failure?
- PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I
- +/- PaCO2 >= 50mmHg (6.7kPa) = Type II
What is type I respiratory failure?
PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I
Hypoxaemia without Hypercapnia
(PaO2 <60mmHg; <8kPa)
What is type II respiratory failure?
+/- PaCO2 >= 50mmHg (6.7kPa) = Type II
- Hypercapnia
Hypoxaemia with Hypercapnia
(PaO2 <60mmHg; <8kPa),
(PaCO2 >50mmHg; >6.7kPa)
What are the 3 stages of respiratory failure?
Depends on previous ABGs
- Acute
- Chronic
- Acute on chronic
What does the Oxyhaemoglobin Dissociation Curve for respiratory failure look like?
What are 10 clinical features of type I respiratory failure?
(Hypoxaemia)
Decreased PaO2 ↔PaCO2
- Restlessness
- Confusion
- Aggression
- Sweating
- Fitting, convulsions
- “Plucking”
- Increased RR, HR, BP
- ECG changes
- Blurred vision, tunnel vision
- Pallor
What are 7 clinical features of type II respiratory failure?
(Hypoxaemia + Hypercapnia)
Decreased PaO2; Increased PaCO2
- Flushed skin
- Drowsiness
- Warm peripheries
- Bounding pulse
- Headache
- Convulsions
- Coma
What are the 4 managements of Type I respiratory failure?
Improve ventilation
- Breathing exercises
- NIV = IPPB or CPAP
Mobilise & remove secretions
- ACTs
- Suction
NB: Will depend on level of co-operation
What are the 3 managements of Type II respiratory failure?
- Oxygen therapy
- NIV = BiPAP OR
- Intubation = SIMV
- Deload lungs, remove CO2
What is the problem, evidence, management and outcome measures of Type I respiratory failure?
What is the problem, evidence, management and outcome measures of Type II respiratory failure?
What are the 4 mechanisms of pulse oximetry?
“SpO2” = % of O2 carried by Haemoglobin (Hb)
- Two light emitting diodes
- Visible red spectrum
- Infrared spectrum
- Beams of light pass through tissues to photodetector
- Light absorbed by blood and soft tissues
- Amount of light absorption depends on degree of oxygenation of Hb within the tissues
What are the 2 values of the pulse oximetry? What are 5 problems that causes the pulse oximetry to be inaccurate?
- Normal SpO2 = ≥96%
- No information on PaCO2
- Low perfusion
- Hypotension
- Movement
- Skin pigmentation
- Nail polish