Oxygen Therapy & Nebulisers

Question 1

What is oxygen therapy

Answer 1

the administration of O2 at concentrations greater than in the ambient air with the intention of treating or preventing the symptoms and manifestations of hypoxia.

Question 2

O2 targets and monitoring

Answer 2

O2 saturations should be monitored at least every 4hrs and documented on either Scale1 or Scale two of SPO2 parameter of a NEWS2 chart.

SPO2 Scale1
- normal, not at risk of CO2 retention; 95-98%

SPO2 Scale2
- used in COPD patients/those at risk of CO2 retention; 88-92%

Only a doctor or advanced nurse practitioner (ANP) can prescribe O2; which is a drug and must always be prescribed unless it is an emergency.

Question 3

what is a nebuliser

Answer 3

a device used to reduce liquid medications to extremely fine cloud particles, and so is useful when delivering medication to deeper parts of the respiratory tract.

an example of a nebuliser medication is salbutamol.

Question 4

Oxygen delivery systems;

Answer 4

• nasal cannula
• simple face mask
• venturi mask
• non re-breather mask

Question 5

reasons for O2 therapy

Answer 5

respiratory failure
-where the circulating blood has too little O2 and too much CO2

respiratory disease
- e.g. COPD, asthma, etc. which can cause the above to happen

sepsis
-infection of the blood can cause low BP and therefore not enough circulating blood/adequate O2 perfusion of tissues

shock
-can cause same above effect

critical illness

intra-operatively and post-operatively patients

Question 6

what is O2?

Answer 6

a drug that must be prescribed out-with emergency situations

Question 7

external risks of O2 therapy

Answer 7

dried mucous membranes, e.g. dry, sore mouth

irritated skin behind the ears

pressure sores on cheeks and bridge of nose

smoking around O2 can cause a fire

CO2 retention

Question 8

what is CO2 retention and who can it happen to?

Answer 8

this occurs when not enough waste (CO2) is exhaled (excreted) from the body causing it to build up in the lungs and blood.

this is common in those with respiratory problems, such as COPD but can happen to anybody with breathing difficulties and those on O2 therapy.

Question 9

what is ventilation perfusion mismatch?

Answer 9

when we receive more O2 than we need, which throws off our gas levels.

a cause of CO2 retention. this occurs when our bodies confuse which areas of the lungs to priorities, which reduces gas exchange efficiency in the lungs.

high-flow O2 therapy, COPD patients and as a result of their symptoms can throw of the ventilation-perfusion ratio, causing the body to direct inhaled O2 to damaged areas of the lungs.

this results in hypoxaemia, hypercapnia and (dyspnoea).

Question 10

how does excessive O2 therapy cause CO2 retention?

Answer 10

too much O2 therapy can cause co2 retention in the blood (hypercapnia). this happens because as more O2 is being inhaled in the lungs, the RBCs drop their CO2 before they reach the alveolis’ to pick up the new O2. this causes the CO2 to dissolve into the blood instead of being exhaled via the lungs.

Question 11

the best way to avoid O2-therapy induced retention?

Answer 11

follow O2 prescriptions exactly and aim for the individual patient’s target range.

Question 12

difference between air outlets and O2 outlets

Answer 12

Air outlets

• often black wall outlets
• contain air; several elements including O2, nitrogen and CO2

O2 outlets

• often white
• contain pure O2

Question 13

what is an O2 flow meter/rate?

Answer 13

a flow meter is used to regulate the flow of O2 and O2 humidification. they do this by measuring the O2 delivered from 0L/min to 15L/min. there is a ball inside this meter that indicates current flow rate of O2; where the line in the middle tells us this.

Question 14

starting O2 therapy points;

Answer 14

Scale 1

• if target range is 94-98%, choose appropriate O2 device to achieve prescribed target saturation
• monitor SPO2 for the first 5minutes, then for a minimum of 4hrly intervals
• provided they stay within target range, there is no need for a ABGT

Scale 2

• if target range is 88-92%, consider a fixed-performance O2 delivery O2 device (venturi mask) to give O2 in a controlled way
• monitor with SPO2 scale
• after any increase in O2 for hyoercapnic patients, repeat ABGT should be carried out 30-60 minutes after this

Question 15

maintaining O2 sats

Answer 15

• adjust O2 delivery devices & flow rate to meet target O2 sats as quickly as possible
• ensure correct positioning (upright when awake)
• encourage to cough to clear secretions
• if changing O2 delivery device, document this & new %, ensuring after 5mins of this that patient reaches target range with it and document
• if SPO2 is higher than target range after this, decrease O2 at this point
• if there is an increase in O2 requirements, medical assessment should be arranged which may include ABGT
• is reservoir mask is required, inform senior staff

Question 16

stopping O2 therapy;

Answer 16

if O2 sats of a patient on low O2 therapy are within normal ranges for them as an individual on two consecutive obs, the patient is deemed stable and O2 therapy should stop.

O2 sats should be monitored for 5mins after stopping O2 therapy and final reading documented

provided their O2 sats remain stable, their O2 stats should be monitored at rest over the next hour while on Air. due to long periods of inactivity, their sats may drop after activity and provide inaccurate readings, rest is best for reading new off air sats.

regular obs should be carried out thereafter if they are still within their target range off O2 during the hour coming from removal

if O2 levels drop as a result of stopping O2 therapy, restart the previous level of O2 therapy %

if they experience acute deterioration or O2 sats drop below target range despite restarting O2 therapy, arrange immediate medical review

if O2 is no longer required, this should be documented along with the reason why and code for stopping of medication