Key messages from the British Thoracic Society Emergency Oxygen Guideline

1. Key messages from the British Thoracic Society Emergency Oxygen Guideline This presentation was last updated on 19-07-2010

2. Oxygen - there is a problem Published audits have shown • Doctors and nurses have a poor understanding of how oxygen should be used • Oxygen is often given without any prescription • If there is a prescription, it is unusual for the patient to receive what is specified on the prescription

3. Oxygen - there was a disagreement • Chest Physicians • Intensivists / Anaesthetists • Emergency Medicine / A&E clinicians • Ambulance teams

4. Time to do something! The British Thoracic Society, together with 21 other Societies and Colleges has produced a multi-discipline Guideline for emergency oxygen use. This Guideline covers most aspects of emergency oxygen use in pre-hospital care and in emergency hospital care for adults (excludes NIV and IPPV)

5. British Thoracic Society Guideline for emergency oxygen use in adult patients Endorsed by: Association of Respiratory Nurse Specialists Association for Respiratory Technology and Physiology British Association for Emergency Medicine British Cardiovascular Society British Geriatric Society British Paramedic Association Chartered Society of Physiotherapy General Practice Airways Group (GPIAG) Intensive Care Society Joint Royal Colleges Ambulance Liaison Committee Resuscitation Council (UK) Royal College of Anaesthetists Royal College of General Practitioners Royal College of Midwives Royal College of Nursing Royal College of Obstetricians and Gynaecologists (approved) Royal College of Physicians (London, Glasgow, Edinburgh) Royal Pharmaceutical Society of Great Britain Society for Acute Medicine O’Driscoll BR. Howard LS, Davison AG. Thorax 2008; 63 Suppl VI

6. Basis of the BTS guidelinePrescribing by target oxygen saturationKeep it normal/near-normal for all patients except pre-defined groups who are at risk from hypercapnic respiratory failure

7. What is normal and what is dangerous?

8. Normal Range for Oxygen saturation Normal range for healthy young adults is approximately 96-98%(Crapo AJRCCM, 1999;160:1525) 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: 131-136 An audit in Salford and Southend showed mean SpO2 of 96.7% with SD 1.9 in 320 stable hospital patients aged >70 O’Driscoll R et al Thorax 2008; 63(suppl Vii): A126

9. Effects of sudden hypoxia(e.g Removal of oxygen mask at altitude or in a pressure chamber) • Impaired mental function; Mean onset at SaO2 64% No evidence of impairment above 84% saturation • Loss of consciousness at mean saturation of 56% • Test Pilots in decompression chambers do not experience breathlessness when the oxygen tension is lowered Akero A et al Eur Respir J. 2005 ;25:725-30 Cottrell JJ et al Aviat Space Environ Med. 1995 ;66:126-30 Hoffman C, et al. Am J Physiol 1946, 145, 685-692

10. What happens at 9,000 metres (approximately 29,000 feet) – it depends Atmospheric pO2 5.7 kPa at 9,000m (Sea level pO2 is 20 kPa) PaO2 ~3.3 kPa and arterial oxygen saturation ~54% SaO2 34-70% at 8400m (Mean 54%, n=4) Grocott M et al NEJM 2009: 360:140-149 SUDDEN ACCLIMATISATION Passengers unconscious in <60 seconds if depressurised Everest has been climbed without oxygen

11. Why is oxygen used?

12. Aims of emergency oxygen therapy • To correct or prevent potentially harmful hypoxaemia • To alleviate breathlessness (only if hypoxaemic) Oxygen has no effect on breathlessness if the oxygen saturation is normal

13. Fallacies regarding Oxygen Therapy“Routine administration of supplemental oxygen is useful, harmless and clinically indicated” Little increase in oxygen-carrying capacity Renders pulse oximetry worthless as a measure of ventilation May prevent early diagnosis & specific treatment of hypoventilation This guideline only recommends supplemental oxygen when SpO2 is below the target range or in critical illness or CO Poisoning John B Downs MD Respiratory care 2003;48:611-20

14. 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

15. Defining safe lower and upper limits of oxygen saturation

16. 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

17. Exposure to high concentrations of oxygen may be harmful Absorption Atelectasis even at FIO2 30-50% Intrapulmonary shunting Post-operative hypoxaemia (on return to room air) Risk to COPD patients Coronary vasoconstriction Increased Systemic Vascular Resistance Reduced Cardiac Index Possible reperfusion injury post MI Hyperoxaemia was associated with INCREASED mortality in survivors of cardiac arrest Oxygen therapy INCREASED mortality in non-hypoxic patients with mild-moderate stroke This guideline recommends an upper limit of 98% for most patients. Combination of what is normal and safe Downs JB. Respiratory Care 2003; 48: 611-20 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; 1406-7 Ronning OM et al. Stroke 1999; 30 : 2033-37 Kilgannon JH et al. JAMA 2010; 302: 2165-71

18. Exposure to high concentrations of oxygen may be harmful Absorption Atelectasis even at FIO2 30-50%1 Intrapulmonary shunting1 Post-operative hypoxaemia (on return to room air)1 Risk to COPD patients2 Coronary vasoconstriction3 Increased Systemic Vascular Resistance3 Reduced Cardiac Index after coronary bypass surgery4 Possible reperfusion injury post Myocardial Infarction5 Oxygen therapy increased mortality in non-hypoxic patients with mild-moderate stroke6 Hyperoxaemia was associated with increased mortality in survivors of cardiac arrest7 This guideline recommends an upper limit of 98% for most patients. Combination of what is normal and safe 1. Downs JB. Respiratory Care 2003; 48: 611-20 5. Kaneda T et al. Jpn Circ J 2001; 213-8 2. Thomson AJ et al. BMJ 2002; 1406-7 6. Ronning OM et al. Stroke 1999; 30 : 2033-37 3. Farquhar H et al. Am Heart J. 2009;158:371-7 7. Kilgannon JH et al. JAMA 2010; 302: 2165-71 4. Harten JM et al J Cardiothoracic Vasc Anaesth 2005; 19: 173-5

19. 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 • Obesity hypoventilation

20. What is a safe lower Oxygen level in acute COPD? In acute COPD pO2 above 6.7 kPa or 50 mm Hg will prevent death SaO2 above about 85% (Keep SpO2≥88% to allow for oximeter error and ensure PaO2 >85% ) OxyHaemoglobin Dissociation Curve SaO2 mmHg PaO2 Murphy R, Driscoll P, O’Driscoll R Emerg Med J 2001; 18:333-9 This guideline recommends a minimum Sp02 of 88% for most COPD patients

21. What is a safe upper limit of oxygen target range in acute COPD ? 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 Plant et al Thorax 2000; 55:550

22. 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 and what is safe Most patients 94 - 98% Risk of hypercapnic respiratory failure 88 – 92%* *Or patient specific saturation on Alert Card

23. Using Target Saturation Scheme • O2 prescribed by target saturation (like an Insulin “BM sliding-scale chart”) • Oxygen delivery device and flow administered and changed if necessary to keep the SpO2 in the target range • Target oxygen saturation prescription integrated into patient drug chart and monitoring

24. 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 • Use of oxygen alert cards • Issue of personal Venturi masks to high-risk patients

25. OXYGEN ALERT CARD Name: ______________________________ I am at risk of type II respiratory failure with a raised CO2 level. Please use my % Venturi mask to achieve an oxygen saturation of _____ % to _____ % during exacerbations Use compressed air to drive nebulisers (with nasal oxygen a 2 l/min). If compressed air not available, limit oxygen-driven nebulisers to 6 minutes.

26. Oxygen Alert Cards and Venturi masks can avoid hypercapnic respiratory failure associated with high flow oxygen masks • Oxygen alert card (and a 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 Venturi mask: 63% in Ambulance 94% in A&E Gooptu B, Ward L, Davison A et al. Oxygen alert cards and controlled oxygen masks: Emerg Med J 2006; 23:636-8

27. Danger of Rebound Hypoxaemia If you find a patient who is severely hypercapnic due to excessive oxygen therapy (e.g pH 7.23 Pa CO2 13 PaO2 35) Do NOT stop oxygen therapy abruptly. The PaCO2 is very high which causes low PAO2 due to the Alveolar Gas Equation (PAO2 ≈ PIO2 –PACO2/RER ) If suddenly changed to air -- PAO2 = 20 – 16.2 = 4 kPa ( PaO2 will be even lower) It is safest to step down to 35% oxygen if the patient is fully alert or call your Critical Care team arrive to provide mechanical ventilation if the patient is drowsy.

28. Prescribing Oxygen

29. Oxygen prescription Model for oxygen section in hospital prescription charts Tick if saturation not indicated

30. Oxygen prescription and Administration • Clinician (usually a doctor) prescribes oxygen by circling the desired oxygen saturation target range • Staff use appropriate device and flow rates in order to maintain saturation within the target range

31. 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 hypoxic cancer patients • Morphine and Midazolam may also relieve breathlessness

32. Devices

33. High Concentration Reservoir Mask • 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.

34. Nasal Cannulae • Recommended in the Guideline as suitable for most patients with both type I and II respiratory failure. • 2-6L/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)

35. Simple face mask(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 (although packaging may say 2-10L)

36. Venturi or Fixed Performance Masks 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 supply should be increased by 50% Increasing flow does not increase oxygen concentration

38. 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/minFor 28% Venturi mask, 4 l/min oxygen flow, gives a total gas flow of 44 l/min(Table 10.2)

39. Oxygen Flow MeterThe 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

40. What device and flow rate should you use in each situation?

41. Acute Patients Stable Patients Standard Oxygen Therapy 1960s-2008

42. Selected COPD patients Critical illness Oxygen therapy 2008 onwards Most patients

43. 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

44. BTS Recommendations Prescribe to target

45. Prior to Blood Gas Analysis Is the patient critically ill*? Yes – treat with reservoir or bag-valve mask No Is the patient at risk of hypercapnic respiratory failure? No – is SpO2 < 85%? Yes – aim for SpO2 88-92% or level on alert card pending ABG No – aim for SpO2 94-98% Start with 24 or 28% Venturi mask Start with nasal cannulae (2-6 l/min) or face mask (5-10 l/min) *Critical illness is defined as cardiopulmonary arrest, shock, major trauma & head injury, near-drowning, anaphylaxis, major pulmonary haemorrhage and carbon monoxide poisoning.

46. Yes – aim for SpO2 88-92% or level on alert card pending ABG Reduce FiO2 if SpO2 > 92% Perform Arterial Blood Gases pH < 7.35 and PaCO2 > 6.0 kPa or patient tiring Consider NIV or IPPV

47. Yes – aim for SpO2 88-92% or level on alert card pending ABG Reduce FiO2 if SpO2 > 92% Perform Arterial Blood Gases pH < 7.35 and PaCO2 > 6.0 kPa or patient tiring pH > 7.35 and PaCO2 > 6.0 kPa Consider NIV or IPPV Maintain SpO2 88-92% with lowest FiO2 Repeat ABG in 30-60 mins

48. Yes – aim for SpO2 88-92% or level on alert card pending ABG Reduce FiO2 if SpO2 > 92% Perform Arterial Blood Gases pH < 7.35 and PaCO2 > 6.0 kPa or patient tiring pH > 7.35 and PaCO2 > 6.0 kPa PaCO2 < 6.0 kPa Consider NIV or IPPV Maintain SpO2 88-92% with lowest FiO2 Maintain SpO2 94-98% with lowest FiO2 unless previous NIV or IPPV Repeat ABG in 30-60 mins

49. Titrating Oxygen up and down. This table below shows APPROXIMATE conversion values. Venturi 24% (blue) 2-4l/min OR Nasal specs 1L Venturi 28% (white) 4-6 l/min OR Nasal specs 2L Venturi 35% (yellow) 8-10l/min OR Nasal spec 4L Venturi 40%(red)10-12l/min OR Simple face mask 5-6L/min Venturi 60% (green) 15l/min OR Simple face mask 7-10L/min Reservoir mask at 15L oxygen flow seek medical advice I f reservoir mask required seek senior medical Input immediately

50. Monitoring patients • Oxygen saturation and delivery system should be recorded on the monitoring chart. • Delivery devices and/or flow rates should be adjusted to keep oxygen saturation in target range.