Sleep apnoea and oxygen therapy. Flashcards
Sources of oxygen
Oxygen cylinder
Wall supply
Oxygen concentrators
Liquid oxygen
Oxygen cylinders
Supplies 100%.
Comes in various sizes and only gives O2 for a limited length of time.
Used for treatments that last for a short duration.
Wall supply of O2
Only available in the hospital
Supplies 100%.
Oxygen concentrators
Machine that has a molecular sleeve to remove nitrogen.
Concentration >90%.
Mobile use of oxygen
Liquid oxygen
Highly compressed oxygen that allows larger volume of O2.
Not in the UK.
Nasal cannulae
Delivers O2- 24-40%.
Flow rate: 1-4L/min
Uses: mild hypoxaemia
Indication for nasal cannulae
Mild hypoxaemia.
Uncontrolled re-breathe masks
- Example
- Concentration
- Flow
Example- Hudson mask.
Delivers 30-60%
Flow rate: 5-10L/min
Uncontrolled non-rebreathe masks
- Concentration
- Flow rate
- Indication
85-90%
15L/min
Indication- acutely unwell patients.
One way valve prevents room air mixing with O2 supplied.
Venturi masks
Supplies a fixed concentration of O2.
Blue- 24%, 2-4L White- 28% 4-6L Yellow- 35% 8-10L Red- 40% 10-12 L Green- 60% 12-15L
Oxygen concentrations supplied by venturi
24% (blue)
28% (white)
35% (yellow)
40% (red)
60% (green)
4 main clinical indications for O2
- Acutely hypoxaemic patients.
- Chronically hypoxaemic with acute exacerbation.
- Chronically hypoxaemic who are stable.
- Palliative use in cancer.
O2 sat targets in those at risk of hypercapnic patients
88-92%
O2 target for normal adults and most patients
Normal:
96-98%
Patients- 94-98%
Acute hypoxaemia examples
Acute pulmonary oedema.
Acute pneumonia
Acute pneumothorax
Acute asthma
MI
Sepsis
CO poisoning
Acute breathlessness with hypoxaemia
- Risk
- O2 Treatment
- Non-O2 treatment
Risk: acute cardiac arrhythmia and organ failure.
Treatment:
Max O2- high uncontrolled.
Target SpO2- 94-98%
Non-O2:
- Secure airway patency
- Avoid respiratory depressants
- Treat established reason for hypoxaemia
- Possible ventilation (IPPV)
Chronically hypoxaemic with COPD + acute exacerbation.
- Example of exacerbation.
- Treatment
Example:
Bacterial infection
Heart failure episode
Treatment:
- Fixed O2, venturi 24%
- Target SpO2 at 88-92%
- pH kept >7.35
Chronically hypoxaemic with COPD + acute exacerbation.
- Example of exacerbation.
- Treatment
Example:
Bacterial infection
Heart failure episode
Treatment:
- Fixed O2, venturi 24%
- Target SpO2 at 88-92%
- pH kept >7.35
- CO2<6
- pO2 <10
Chronically hypoxaemic patients that are stable:
- Problems if not treated
- O2 therapy
Used in COPD and some bronchiectasis.
Problems caused if not treated:
- Pulmonary artery hypertension.
- RV hypertrophy
- Cor pulmonale.
O2:
LTOT
LTOT
Long term O2 treatment.
Given to some patients with stable COPD.
Areas of the pharynx
Nasopharynx
Oropharynx
Laryngopharynx
What happens to the pharynx during sleep apnoea
The tendency of the pharynx to collapse increases due to the following factors:
- Decrease in the neuromuscular tone of the upper airway (UA).
- Decrease in the caliber of the UA.
- Increase in resistance of the UA.
- Increase in pharyngeal compliance
Sleep apnoea cycle
- Sleep.
- Relaxation of the muscles and tissues surrounding the pharyngeal airway.
- Collapse and obstruction of the airway= snoring.
- Apnoea
- Arousal
- Return of muscular tone
- Resumption of breathing.
CPAP
Continuous positive airway pressure
Used to treat sleep apnoea.
The device generates airflow by delivering positive pressure via a mask.
Keeps the pharynx open by making the intraluminal pharyngeal pressure> surrounding pressure.
Benefits of CPAP
Resolves symptoms
Decreases :
- Apnoea
- Daytime sleepiness
- Risk of road accidents.
Increases quality of life
Problems of CPAP
Mask problems: leaks and discomfort.
Life long
Can cause airway drying and irritation.
Difficult to adhere to
Behavioural changes to manage sleep apnoea
Weight loss
Avoid sleeping supine
Avoiding alcohol
Mandibular advancement devices
Equipment used to treat sleep apnoea.
Holds the soft tissue of the oropharynx forward.
Used for mild-moderate sleep apnoea.
Consequences of obstructive sleep apnoea
Increased risk of road accidents.
Associated with many conditions: T2 diabetes Hypertension IHD Heart failure Stroke Arrythmias Death
