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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
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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 12/05/2017 2
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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 12/05/2017 3
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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What is normal and what is dangerous?
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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) 12/05/2017
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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. 12/05/2017
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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, 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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Why is oxygen used? 12/05/2017
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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 12/05/2017
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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. 12/05/2017
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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 12/05/2017
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Defining safe lower and upper limits of oxygen saturation
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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 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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Use of target ranges 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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Prescribing Oxygen 12/05/2017
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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 12/05/2017
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Example of electronic prescription
*Electronic prescribing can be linked to electronic bedside observations to calculate EWS/NEWS automatically according to oxygen target range. Hypoxaemia 12/05/2017
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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 12/05/2017
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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 12/05/2017
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Devices 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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What device and flow rate should you use in each situation?
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 % 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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Example of 2017 NEWS chart when available
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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 12/05/2017
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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 12/05/2017
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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) 12/05/2017
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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 12/05/2017
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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 12/05/2017
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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.
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