1. Key messages for doctors
British Thoracic Society Guideline for oxygen use in healthcare and emergency settings
Key messages for doctors
This presentation was last updated on 12/05/2017

2. BTS NURSES TRAINING SLIDES MAY 2010(V13)
BTS guideline for oxygen use in adults in healthcare and emergency settings is endorsed by
Association of British Neurologists Association of Chartered Physiotherapists in Respiratory Care Association of Palliative Medicine Association of Respiratory Nurse Specialists Association for Respiratory Technology and Physiology British Association of Stroke Physicians British Geriatric Society College of Paramedics Intensive Care Society Joint Royal Colleges Ambulance Liaison Committee Primary Care Respiratory Society UK Resuscitation Council (UK) Royal College of Anaesthetists The Royal College of Emergency Medicine Royal College of General Practitioners Royal College of Nursing (endorsement until April 2020) Royal College of Obstetricians and Gynaecologists Royal College of Physicians London Royal College of Physicians of Edinburgh Royal College of Physicians and Surgeons of Glasgow Royal Pharmaceutical Society The Society for Acute Medicine
O’Driscoll BR et al Thorax 2017; 72: Suppl 1 i1-i89
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3. BTS guideline for oxygen use in adults in healthcare and emergency settings: Overview
Why have a guideline?
Oximetry as the basis of the guideline
Normal range of oximetry
Effects of hypoxaemia – sudden onset and gradual onset
Aims of oxygen treatment and its place in resuscitation
Recommended target saturations – with rationale
Oxygen Alert cards
Prescribing oxygen
Devices
What device and flow to use
Monitoring
Guideline and this lecture available on BTS website
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4. Oxygen - there is a problem Published audits have shown that…
Doctors and nurses have a poor understanding of how oxygen should be used
Oxygen is often given without a prescription
(In the 2015 BTS audit, 42% of hospital patients using oxygen had no prescription)
If there is a prescription, patients do not always receive what is specified on the prescription
Where there is a prescription with target range, almost one third of patients are outside the range
(9.5% of SpO2 results below target range and 21.5% above target range in 2015 BTS audit)
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5. BTS guideline for oxygen use in adults in healthcare and emergency settings
The British Thoracic Society, together with 21 other Societies and Colleges produced a multi-discipline Guideline for emergency oxygen use in 2008
This Guideline covers all aspects of emergency oxygen use in pre-hospital care and in emergency hospital care
It has been updated and expanded in 2017
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6. Basis of the BTS guideline: Prescribing by target oxygen saturation
Keep the oxygen saturation normal/near-normal for all patients except pre-defined groups who are at risk from hypercapnic respiratory failure
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7. What is normal and what is dangerous?
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8. Normal Range for Oxygen saturation
Normal range for healthy young adults is approximately 96-98% (Crapo AJRCCM, 1999;160:1525)
There is a slight fall with advancing age
A study of 871 subjects showed that age > 60 was associated with minor SpO2 reduction of 0.4% (Witting MD et al Am J Emerg Med 2008: 26: )
An audit in Salford and Southend showed mean SpO2 of 96.7% with SD 1.9 in 320 stable hospital patients aged >70 without lung disease or heart failure (2 SD range 92.9 to 100%)
(O’Driscoll R et al Thorax 2008; 63(suppl Vii): A126)
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9. What is a “normal” nocturnal oxygen saturation?
Healthy subjects in all age groups routinely desaturate to an average nadir of 90.4% during the night (SD 3.1%)
Gries RE et al Chest 1996; 110:
*Therefore, be cautious in interpreting a single oximetry measurement from a sleeping patient. Watch the oximeter for a few minutes if in any doubt (if the patient is otherwise stable) because normal overnight dips are of short duration.
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10. Effects of sudden hypoxaemia (e
Effects of sudden hypoxaemia (e.g Removal of oxygen mask at altitude or in a pressure chamber)
Impaired mental function; Mean onset at SaO2 64% No evidence of mental impairment above SaO2 84%
Loss of consciousness at mean saturation of 56%
Test Pilots in decompression chambers do not experience breathlessness when the oxygen tension is lowered, they make mistakes and then pass out
Akero A et al Eur Respir J ;25:725-30
Cottrell JJ et al Aviat Space Environ Med ;66:126-30
Hoffman C, et al. Am J Physiol 1946, 145,
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11. Clinical features of hypoxaemia
The effects are often non-specific
Depends if onset is chronic or acute
Altered mental state
Dyspnoea, cyanosis, tachypnoea, arrhythmias, coma
Hyperventilation when PaO2 <5.3kPa (saturation <72%)
Loss of consciousness ~ 4.3 kPa (saturation ~56%)
Death approximately 2.7 kPa
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12. Assessment/Measurement of hypoxaemia
CYANOSIS - Often not recognised,
- Absent with anaemia
BLOOD GASES - PaO2 and SaO2
PaO2 = Arterial oxygen partial pressure in blood gas specimen
SaO2 =Arterial oxygen saturation measured in blood gases
OXYGEN SATURATION - Easily measured by pulse oximetry
SpO2 is widely available
SpO2 = Oxygen saturation measured by pulse oximeter
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13. What happens at 9,000 metres (approximately 29,000 feet) – it depends
Atmospheric pO kPa (< 1/3 sea level atmospheric oxygen tension)
PaO2 ~3.3 kPa Arterial Oxygen Saturation ~54%
SUDDEN
ACCLIMATISATION
Passengers unconscious in <60 seconds if depressurised
Everest has been climbed without oxygen
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14. Why is oxygen used?
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15. Aims of emergency oxygen therapy
To correct potentially harmful hypoxaemia
To alleviate breathlessness (only if hypoxaemic)
Oxygen has not been proven to have any consistent effect on the sensation of breathlessness in non-hypoxaemic patients
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16. Fallacies regarding oxygen therapy John B Downs MD Respiratory care 2003;48:611-20
THE FALLACY: “Routine administration of supplemental oxygen is useful, harmless and clinically indicated.”
THE FACTS
Little increase in oxygen-carrying capacity if SpO is normal
Renders pulse oximetry worthless as a measure of ventilation
May prevent early diagnosis & specific treatment of hypoventilation
The guideline only recommends supplemental oxygen when SpO2 is below the target range.
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17. Oxygen therapy is only one element of resuscitation of a critically ill patient
The oxygen carrying power of blood may be increased by
Safeguarding the airway
Enhancing circulating volume
Correcting severe anaemia
Enhancing cardiac output
Avoiding/Reversing Respiratory Depressants
Increasing Fraction of Inspired Oxygen (FIO2)
Establish the reason for Hypoxia and
treat the underlying cause (e.g Bronchospasm, LVF etc)
Patient may need, CPAP or NIV or Invasive ventilation
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18. Defining safe lower and upper limits of oxygen saturation
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19. What is the minimum arterial oxygen level recommended in acute illness?
Target oxygen Saturation
Critical care consensus guidelines Minimum 90%
Surviving sepsis campaign Aim at 88-95%
But these patients have intensive levels of nursing & monitoring
This guideline recommends a minimum of 94% for most patients – combines what is near normal and what is safe
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20. Exposure to high concentrations of oxygen may be harmful
Harten JM et al J Cardiothoracic Vasc Anaesth 2005; 19: 173-5
Kaneda T et al. Jpn Circ J 2001; 213-8
Frobert O et al. Cardiovasc Ultrasound 2004; 2: 22
Haque WA et al. J Am Coll Cardiol 1996; 2: 353-7
Thomaon aj ET AL. BMJ 2002;
Stub D et a;. Circulation 2015’; 131:
Helmerhorst HJ Crit Care Med 2015; 43:
Girardis M et al. JAMA 2016; 316:
Absorption Atelectasis even at FIO %
Intrapulmonary shunting
Post-operative hypoxaemia
Risk to COPD patients
Coronary vasoconstriction
Increased Systemic Vascular Resistance
Reduced Cardiac Index
Possible reperfusion injury post MI
Increased CK level in STEMI and increased infarct size on MR scan at 3 months
Worsens systolic myocardial performance
Association of hyperoxaemia with increased mortality in several ITU studies
This guideline recommends an upper limit of % for most patients
Combination of what is normal and safe
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21. Some patients are at risk of CO2 retention and acidosis if given high dose oxygen*
Chronic hypoxic lung disease
COPD
Severe Chronic Asthma
Bronchiectasis / CF
Chest wall disease
Kyphoscoliosis
Thoracoplasty
Neuromuscular disease
Morbid obesity and OHVS (Obesity Hypoventilation Syndrome)
*Blood gases should be checked for all such patients if they need oxygen
*Target saturation range is 88-92% if CO2 level is elevated (or if it was high in the past)
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22. What is a safe lower Oxygen level in acute COPD?
SaO2
mmHg
PaO2
OxyHaemoglobin Dissociation Curve
In acute COPD
pO2 above 6.7 kPa
or 50 mm Hg
will prevent death
(SpO2 above about 85%)
Murphy R, Driscoll P, O’Driscoll R Emerg Med J 2001; 18:333-9
This guideline recommends a minimum saturation of 88% for most COPD patients
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23. RECOMMENDED UPPER LIMITS
What is a safe upper limit of oxygen target range in acute COPD patients who need oxygen therapy?
47% of 982 patients with exacerbation of COPD were hypercapnic on arrival in hospital
20% had Respiratory Acidosis (pH < 7.35)
5% had pH < 7.25 (and were likely to need ICU care)
Most hypercapnic patients with pO2 > 10 kPa were acidotic (equivalent to oxygen saturation of above ~ 92%) i.e. they had been given too much oxygen
RECOMMENDED UPPER LIMITS
Keep PaO2 below 10 kPa and keep SpO2 ≤ 92% in acute COPD pending blood gas results
(Maintain target range 88-92% if hypercapnic)
Plant et al Thorax 2000; 55:550
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24. High concentration oxygen may double the risk of death in acute exacerbations of COPD (AECOPD)
405 patients with presumed AECOPD were randomised to high concentration oxygen or controlled oxygen (target range 88-92%)
Mortality 9% on high concentration O2 V 4% on controlled O2
Titrated oxygen treatment reduced mortality compared with high flow oxygen by 58% for all patients (relative risk 0.42, 95% confidence interval 0.20 to 0.89; P=0.02)
Less acidosis and less hypercapnia on controlled oxygen therapy
Austin M et al BMJ 2010; 341: c5642
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25. Danger of Rebound Hypoxaemia
If you find a patient who is severely hypercapnic due to excessive oxygen therapy……
Do NOT stop oxygen therapy abruptly
The PaCO2 is very high which will cause low PAO2 as soon as oxygen is removed as demonstrated by the Alveolar Gas Equation (PAO2 ≈ PIO2 –PaCO2/RER )
It is safest to step down to 35% oxygen if the patient is fully alert or call your Critical Care team to provide mechanical ventilation if the patient is drowsy
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26. Use of target ranges
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27. Target Saturation Scheme
O2 prescribed by target saturation
Oxygen delivery device and flow are changed if necessary to keep the SpO2 in the target range
Target oxygen saturation prescription integrated into patient drug chart and monitoring
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28. Recommended target saturations
The target ranges are a consensus agreement by the guidelines group and the endorsing colleges and societies
Rationale for the target saturations is combination of what is normal or near-normal and what is safe
Most patients %
Risk of hypercapnic respiratory failure 88 – 92%*
*Or patient specific saturation on Alert Card
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29. Safeguarding patients at risk of type 2 respiratory failure
Lower target saturation range for these patients (88-92%)
Education of patients and health care workers
Use of controlled oxygen via Venturi masks or low flow nasal O2
Use of oxygen alert cards
Issue of personal Venturi masks to high-risk patients
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30. OXYGEN ALERT CARD
Name: __________________________________________________
I have a chronic respiratory condition and I am at risk of having a raised carbon dioxide level in my blood during flare-ups of my condition (exacerbations)
Please use my ______% Venturi mask to achieve an oxygen saturation of
_____ % to _____ % during exacerbations of my condition
Use compressed air to drive nebulisers (with nasal oxygen a 2 l/min)
If compressed air is not available, limit oxygen-driven nebulisers to 6 minutes
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31. Oxygen Alert Cards and 24% masks can avoid hypercapnic respiratory failure associated with high flow oxygen masks
Oxygen alert card (and a 24% Venturi mask) given to patients admitted with hypercapnic acidosis with a PO2 > 10kPa
Patients instructed to show these to ambulance and A&E staff
After introduction of alert cards
Use of 24% oxygen: 63% in Ambulance
94% in Emergency Department
Gooptu B, Ward L, Davison A et al. Oxygen alert cards and controlled oxygen masks:
Emerg Med J 2006; 23:636-8
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32. Prescribing Oxygen
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33. Oxygen prescription on paper chart
Model for oxygen section in hospital prescription charts
DRUG OXYGEN
(Refer To Trust Oxygen Policy)
Circle target oxygen saturation
88-92% % Other___
STOP DATE
Starting device/flow rate________
PHARM
(Saturation is indicated in almost all cases except for palliative terminal care)
SIGNATURE / PRINT NAME
DATE
ddmmyy
Tick if saturation not indicated
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34. Example of electronic prescription
*Electronic prescribing
can be linked to electronic
bedside observations to
calculate EWS/NEWS
automatically according
to oxygen target range.
Hypoxaemia
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35. Oxygen prescription and Administration
Clinician (usually a doctor) prescribes oxygen by circling the desired oxygen saturation target range (or by selecting a range in electronic prescribing)
Nurses and PAMs* use appropriate devices and flow rates to maintain saturation within the target range
*PAMs = Professions allied to medicine
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36. Oxygen use in palliative care
Most breathlessness in cancer patients is caused by specific issues such as airflow obstruction, infections or pleural effusions and the main issue is to treat the cause
Oxygen has been shown to relieve dyspnoea in hypoxaemic cancer patients but not if PaO2 is >7.3 kPa (saturation above about 90%)
Morphine and Midazolam also relieve breathlessness and are probably more effective
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37. Devices
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38. High Concentration Reservoir Mask (RM)
Non re-breathing Reservoir Mask
Critical illness / Trauma patients
Post-cardiac or respiratory arrest
Delivers O2 concentrations between 60 & 80% or above
Effective for short term treatment
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39. Nasal Cannulae (N)
Recommended in the Guideline as suitable for most patients with both type I and II respiratory failure.
1-6L/min gives approx 24-50% FIO2
FIO2 depends on oxygen flow rate and patient’s minute volume and inspiratory flow and pattern of breathing.
Comfortable and easily tolerated
No re-breathing
Low cost product
Preferred by patients (vs simple mask)
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40. Venturi or Fixed Performance Masks (V)
Aim to deliver constant oxygen concentration within and between breaths.
24-40% Venturi Masks operate accurately A 60% Venturi mask gives ~50% FIO2
With TACHYPNOEA (RR >30/min) the oxygen flow rate should be increased by above the minimum flow rate shown on the packaging - see next slide
Increasing flow does not increase oxygen concentration because it is a fixed dose device
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41. 24% Venturi - 2 L/min - Use 3 l/min if RR >30
60% Venturi - 15 L/min - Change to RM if 60% Venturi is not sufficient
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42. Operation of Venturi valve
Air O2 +
Air O2
Air
For 24% Venturi mask, the typical oxygen flow of 2 l/min gives a total gas flow of 51 l/min For 28% Venturi mask, 4 l/min oxygen flow, gives a total gas flow of 44 l/min(Table 10.2)
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43. Simple face mask (SM) (Medium concentration, variable performance)
Used for patients with type I respiratory failure.
Delivers variable O2 concentration between 35% & 60%.
Low cost product.
Flow 5-10 L/min
Flow must be at least 5 L/min to avoid CO2 build up and resistance to breathing
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44. Humidified Oxygen (H) Tracheostomy Bronchiectasis
Cystic Fibrosis patients
Physiotherapists may advise humidification
Patients on High flow whisper CPAP
Humidification may be provided by cold or warm humidifiers
( H24, H28, H35 etc )
The illustration shows a cold humidifier delivering 28% oxygen at 5 l/min flow
N.B. There is little evidence for humidification in routine oxygen therapy
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45. Tracheostomy Mask (TM)
“Neck breathing patients”
Adjust oxygen flow to maintain target saturation
Prolonged oxygen use requires humidification
Patients may also need suction to remove airway mucus
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46. High flow humidified nasal oxygen (HFN)
High flow nasal oxygen using specialised equipment may be used as an alternative to reservoir mask treatment in patients with acute respiratory failure without hypercapnia
It is mostly used in Intensive Care Units, High Dependency Units and other specialised areas
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47. Oxygen Flow Meter
The centre of the ball indicates the correct flow rate.
This diagram illustrates the correct setting of the flow meter to deliver a flow of 2 litres per minute
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48. Beware of air outlets They may be mistaken for oxygen outlets
Use a cover for air outlets or else remove the flow meter for air when not in use
Oxygen outlet
(Usually white)
Air outlet
(usually black)
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49. What device and flow rate should you use in each situation?
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50. Many patients need high-dose oxygen to normalize saturation
Severe Pneumonia
Severe LVF
Major Trauma
Sepsis and Shock
Major atelectasis
Pulmonary Embolism
Lung Fibrosis
Etc etc etc
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51. Oxygen use in specific illnesses 4 Major groups of patients See Tables 1-4 and Charts 1-2 in BTS Emergency Oxygen Guideline
Critical illness requiring high levels of supplemental oxygen
Serious illness requiring moderate levels of supplemental oxygen if a patient is hypoxaemic
COPD and other conditions requiring controlled or low-dose oxygen therapy
Conditions for which patients should be monitored closely but oxygen therapy is not required unless the patient is hypoxaemic (This group includes most cases of chest pain, heart attacks, stroke etc)
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52. Chart 1 Oxygen prescription for acutely hypoxaemic patients in hospital
Is the patient critically ill (see Table 1 and section in Guideline)
Commence treatment with reservoir mask or bag-valve mask and manage as advised in Table 1
Yes No
Is this patient at risk of hypercapnic respiratory failure
(Type 2 Respiratory Failure)?
YES
Target saturation is 88-92% whilst awaiting blood gas results NO
Aim for SpO %
Specific instructions are given for each category of patient depending on blood gas results etc
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53. YES No known Risk (Risk of CO2 Retention) of CO2 Retention SpO2 ≤ 93%
Obtain ABGs
Yes
CHECK ABGs No
pH <7.35
and PCO2 > 6.0
(Respiratory Acidosis)
or patient tiring
pH > 7.35
and PaCO2 >6kPa
(Hypercapnia)
PCO2 < 6.0
(Normal or low)
PCO2 >6.0
or patient tiring
Monitor SpO2
Oxygen may not be required
Prescribe target range in case SpO2 falls
Seek immediate senior review
Consider invasive ventilation
Seek immediate senior review
Consider NIV or invasive ventilation
Treat with low flow nasal oxygen or lowest strength Venturi mask
that will keep SpO2 between 88-92%
Treat with lowest FiO2 via Venturi mask or 1-2 l/ min nasal oxygen to keep SpO % pending senior medical advice or NIV or ICU admission
Repeat ABG’s:
If Respiratory Acidosis
( pH <7.35 & PCO2>6.0) Seek immediate senior review, consider NIV/ICU.
Consider reducing FiO2
if PO2 > 8.0 kPa
Treat appropriately aiming to keep SpO %
and repeat gases in minutes
Treat urgently. Aim for SpO2 of % until immediate senior review.
Also consider COPD needing SpO %
Treat appropriately aiming to keep SpO %
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54. Titrating Oxygen up and down
This table below shows APPROXIMATE conversion values.
Venturi 24% (blue) 2-3 l/min OR
Nasal cannulae 1L
Venturi 28% (white) 4-6 l/min
Nasal cannulae 2L
Venturi 35% (yellow) 8-12 l/min
Nasal cannulae 4L
Venturi 40% (red) l/min
Nasal cannulae or Simple face mask 5-6L/min
Venturi 60% (green) 15 l/min
Simple face mask 7-10L/min
Reservoir mask at 15L oxygen flow
Seek medical advice
If reservoir mask required
seek senior medical input immediately
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55. FLOW CHART FOR OXYGEN ADMINISTRATION ON GENERAL WARDS IN HOSPITALS
See target saturation in the patient’s drug chart. Choose the most suitable delivery system and flow rate
Titrate oxygen up or down to maintain the target oxygen saturation
The table below shows available options for stepping dosage up or down.
The chart does NOT imply any equivalence of dose between Venturi masks and nasal cannulae.
Allow at least 5 minutes at each dose before adjusting further upwards or downwards
(except with major and sudden fall in saturation – falls ≥3% also require clinical review)
Once your patient has adequate and stable saturation on minimal oxygen dose, consider discontinuation of oxygen therapy.
Patients in a peri-arrest situation and critically ill patients should be given oxygen therapy at 15 l/min via reservoir mask or bag-valve mask whilst immediate medical help is arriving.
(Except for patients with COPD with known oxygen sensitivity recorded in patient’s case notes and drug chart or in the Electronic Patient Record (EPR): keep saturation at 88-92% for this sub-group of patients)
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56. Monitoring patients
Oxygen saturation and delivery system should be recorded on the bedside monitoring chart or EPR
Delivery devices and/or flow rates should be adjusted to keep oxygen saturation in target range
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57. Key elements of an oxygen observation chart
*It is recommended that the 2017 NEWS chart should be used*
Respiratory Rate, Oxygen saturation and oxygen therapy
Clinical review required if saturation is outside target range
Target range: % % Other________
Respiratory
Rate
Oxygen
Saturation %
Device or Air
Oxygen flow rate L/min
Your
Initials*
*All changes to oxygen delivery systems must be initialled by a registered nurse or equivalent
If the patient is medically stable and in the target range on two consecutive rounds, report to a registered nurse to consider weaning off oxygen
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58. Example of 2017 NEWS chart when available
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59. Standard abbreviations for oxygen delivery devices
A Air
N Nasal Cannulae
HFN High Flow Humidified Nasal Cannulae
V24 Venturi Mask 24%
V Venturi Mask 28%
V35 Venturi Mask 35%
V40 Venturi Mask 40%
V Venturi Mask 60%
H28 Humidified O2 28%
H Humidified O2 40%
H Humidified O2 60%
RM Reservoir Mask
SM Simple Face Mask
TM Tracheostomy Mask
CPAP Continuous Positive
Airway Pressure
NIV Non-Invasive
Ventilation
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60. From the BTS Emergency Oxygen Guideline To the patient
Guideline agreed by the whole UK medical, nursing and AHP community (endorsed by 23 Colleges and Societies)
Medical and Nurse/Physio Champions in every Hospital Trust
Clear prescription charts and monitoring charts in every hospital
Training packages on BTS website
Audit tools on BTS website: audits.brit-thoracic.org.uk
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61. National BTS audits of oxygen use 2008-2016 14% of UK hospital patients were using oxygen
Percent of patients using oxygen who had an oxygen prescription during BTS audits:
32% in 2008 (99 Hospitals) Prior to publication of 2008 Guideline
48% in (156 Hospitals)
55.1% in (151 Hospitals)
57.5% in (181 Hospitals)
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62. 2015 BTS Oxygen Audit 4083 patients on oxygen with prescribed target range
69% of SpO2 observations were within the target range
21.5% of SpO2 observations were above the target range
9.5% of SpO2 observations were below the target range
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63. Summary
Prescribe oxygen to a target saturation for each group of patients
% for most adult patients
% if risk of hypercapnia (or patient-specific target on alert card)
Administer oxygen to achieve target saturation
Monitor oxygen saturation and keep in target range
Taper oxygen dose and stop when stable
Audit your practice
All information on
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64. These slides are provided for use on a local basis – permission is not request to use these and additional material may be added depending on local circumstances. The BTS Guidelines for oxygen use in adults in healthcare and emergency settings should be acknowledged and referenced as follows: O’Driscoll BR et al Thorax 2017; 72: Suppl 1 i1-i89
Healthcare providers need to use clinical judgement, knowledge and expertise when deciding whether it is appropriate to apply recommendations for the management of patients. The recommendations cited here are a guide and may not be appropriate for use in all situations. The guidance provided does not override the responsibility of healthcare professionals to make decisions appropriate to the circumstances of each patient, in consultation with the patient and/or their guardian or carer.