British Thoracic SocietyBritish Thoracic SocietyGuideline for emergency oxygen use in adult patientsGuideline for emergency oxygen use in adult patientsEndorsed by:Association of Respiratory Nurse SpecialistsAssociation for Respiratory Technology and PhysiologyBritish Association for Emergency MedicineBritish Cardiovascular SocietyBritish Geriatric SocietyBritish Paramedic AssociationChartered Society of PhysiotherapyGeneral Practice Airways Group (GPIAG)Intensive Care SocietyJoint Royal Colleges Ambulance Liaison CommitteeResuscitation Council (UK)Royal College of AnaesthetistsRoyal College of General PractitionersRoyal College of MidwivesRoyal College of NursingRoyal College of Obstetricians and Gynaecologists (approved)Royal College of Physicians (London, Glasgow, Edinburgh)Royal Pharmaceutical Society of Great BritainSociety for Acute Medicine

O’Driscoll BR. Howard LS, Davison AG. Thorax 2008; 63 Suppl VI

British Thoracic SocietyBritish Thoracic Society Guideline for emergency Guideline for emergency oxygen use in adult patientsoxygen use in adult patients

OverviewOverview

Why have a guideline?Oximetry as the basis of the guidelineNormal range of oximetryEffects of hypoxia – sudden and gradual onsetAims of oxygen treatment and its place in resuscitation Recommended target saturations – with rationaleOxygen Alert cardsPrescribing oxygen DevicesWhat device and flow to useMonitoringGuideline and this lecture available on BTS website www.brit-thoracic.org.uk

Oxygen Oxygen -- there is a problemthere 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

Oxygen Oxygen -- there was a disagreementthere was a disagreement

• Chest Physicians

• Intensivists

• Emergency Medicine / A&E clinicians

• Ambulance teams

Time to do something!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 all aspects of emergency oxygen use in pre-hospital care and in emergency hospital care

Assessment/Measurement of Assessment/Measurement of HypoxaemiaHypoxaemia

CYANOSIS - Often not recognised, - Absent with anaemia

BLOOD GASES - PaO2

OXYGEN SATURATION - Easily measured - Widely available

Prescribing by target oxygen saturationPrescribing by target oxygen saturationBasis of the BTS guidelineBasis of the BTS guideline

Keep it normal/nearKeep it normal/near--normal for all patients except prenormal for all patients except pre--defined defined groups who are at risk from groups who are at risk from hypercapnichypercapnic respiratory failurerespiratory failure

What is normal and What is normal and what is dangerous?what is dangerous?

Normal Range for Oxygen saturationNormal Range for Oxygen saturationNormal range for healthy young adults is approximately 96-98% (Crapo AJRCCM, 1999;160:1525)

Previous literature suggested a gradual fall with advancing age

However, a recent Salford/Southend audit of 320 stable adults aged >70 found

•Mean SpO2 96.7% 2SD range 93.1-100%

What is a What is a ““normalnormal””nocturnal oxygen saturation?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: 1489-92

*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 othewisestable) as normal overnight dips are of short duration.

Clinical features of Clinical features of HypoxaemiaHypoxaemia

Often non-specificDepends 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• Death approximately 2.7 kPa

Effects of sudden hypoxiaEffects of sudden hypoxia((e.ge.g Removal of oxygen mask at altitude or in a pressure chamber)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%

Note absence of breathlessness when healthy resting subjects are exposed to sudden severe hypoxia

Also note that the mean SpO2 of airline passengers in a pressurised cabin falls from 97% to 93% (average nadir 88.6%) with no symptoms and no apparent effects

Akero A et al Eur Respir J. 2005 ;25:725-30 Cottrell JJ et al Aviat Space Environ Med. 1995 ;66:126-30Hoffman C, et al. Am J Physiol 1946, 145, 685-692

What happens at 9,000 metres What happens at 9,000 metres (approximately 29,000 feet) (approximately 29,000 feet) –– it dependsit depends

Atmospheric pO2 6.2 kPa (< 1/3 sea level pO2) PaO2 ~3.3 kPaArterial Oxygen Saturation ~70%

Passengers unconscious in <60 seconds if depressurised

Everest has been climbed without oxygen

SUDDEN ACCLIMATISATION

Why is oxygen Why is oxygen used?used?

Aims of emergency oxygen therapyAims 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

But some patients are at risk of CO2 But some patients are at risk of CO2 retention and acidosis if given high dose retention and acidosis if given high dose oxygenoxygen• Chronic hypoxic lung disease

– COPD– Severe Chronic Asthma– Bronchiectasis / CF

• Chest wall disease– Kyphoscoliosis– Thoracoplasty

• Neuromuscular disease• Obesity hypoventilation

Oxygen therapy is only one element of Oxygen therapy is only one element of resuscitation of a critically ill patientresuscitation of a critically ill patient

The oxygen carrying power of blood may be increased by • Enhancing circulating volume• Correcting severe anaemia• Enhancing cardiac output• Safeguarding the airway• 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

Defining safe lower Defining safe lower and upper limits of and upper limits of oxygen saturationoxygen saturation

What is the minimum arterial oxygen What is the minimum arterial oxygen level recommended in acute illnesslevel recommended in acute illness

Target oxygen SaturationCritical care consensus guidelines Minimum 90%

Surviving sepsis campaign aim at 88-95%

But these patients have intensive levels of nursing and monitoring

This guideline recommends a minimum of 94% for most patients – combines what is near normal and what is safe

Exposure to high concentrations of oxygenExposure to high concentrations of oxygenmay be harmfulmay be harmful

• Absorption Atelectasis even at FIO2 30-50%• Intrapulmonary shunting• Post-operative hypoxaemia• Risk to COPD patients• Coronary vasoconstriction• Increased Systemic Vascular Resistance • Reduced Cardiac Index• Possible reperfusion injury post MI• Worsens systolic myocardial performance• Oxygen therapy INCREASED mortality in non-hypoxic patients with mild-

moderate strokeRECOMMENDATION – This guideline recommends an upper limit of 98% for most

patients. This is a combination of what is normal and safeHarten JM et al J Cardiothoracic Vasc Anaesth 2005; 19: 173-5Kaneda T et al. Jpn Circ J 2001; 213-8Frobert O et al. Cardiovasc Ultrasound 2004; 2: 22Haque WA et al. J Am Coll Cardiol 1996; 2: 353-7Thomaon aj ET AL. BMJ 2002; 1406-7Ronning OM et al. Stroke 1999; 30

What is a safe lower Oxygen level in acute What is a safe lower Oxygen level in acute COPD?COPD?

pO2 above 6.7 kPaor 50 mm Hg in acute COPD will prevent death(SpO2 above about 85%)

SaO

2mmHg

PaO2

OxyHaemoglobin Dissociation Curve

This guideline recommends a minimum oxygen saturation of 88% for most patients with COPDMurphy R, Driscoll P, O’Driscoll R Emerg Med J 2001; 18:333-9

What is a safe higher oxygen level in acute What is a safe higher oxygen level in acute COPDCOPD

• 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. had been given too much oxygen

RECOMMENDATION: Keep PaO2 below 10 kPa and SpO2 < 92% in acute COPD

Plant et al Thorax 2000; 55:550

Fallacies regarding Oxygen TherapyFallacies regarding Oxygen Therapy

““Routine administration of supplemental oxygen is Routine administration of supplemental oxygen is useful, harmless and clinically indicateduseful, harmless and clinically indicated””

• Renders pulse oximetry worthless as a measure of ventilation.

• May prevent early diagnosis and specific treatment of hypoventilation.

This guideline only recommends supplemental oxygen when the patients oximetry is below the target range.

John B Downs MD Respiratory care 2003;48:611-20

Fallacies regarding Oxygen TherapyFallacies regarding Oxygen Therapy

““High FIOHigh FIO22 is Protective for individuals is Protective for individuals at risk of at risk of hypoxaemiahypoxaemia””

• Little increase in oxygen-carrying capacity

• No known clinical benefit in elevating saturation above 90%

This guideline recommends an upper limit of98% for patients not at risk of acute hypercapnic respiratory failure

John B Downs MD Respiratory Care 2003; 48:611-20

Use of target rangesUse of target ranges

Target Saturation SchemeTarget 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

Recommended target saturationsRecommended target saturations

The target ranges are a consensus agreement by the guidelines group and the endorsing colleges and

societiesRationale for the target saturations is combination of what is normal and what is safeMost patients 94 - 98%Risk of hypercapnic respiratory failure 88 – 92%*

*Or patient specific saturation on Alert Card

Safeguarding patients at risk of Safeguarding patients at risk of type 2 respiratory failuretype 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

Oxygen Alert Cards and 24% masks Oxygen Alert Cards and 24% masks (recommended in (recommended in guideline) guideline) can avoid can avoid hypercapnichypercapnic respiratory failure respiratory failure

associated with high flow oxygen masksassociated 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 A&E

Gooptu B, Ward L, Davison A et al. Oxygen alert cards and controlled oxygen masks: Emerg Med J 2006; 23:636-8

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 at 2 l/min).If compressed air not available, limit oxygen-driven nebulisers to 6 minutes.

Prescribing OxygenPrescribing Oxygen

Oxygen prescriptionOxygen prescription

Model for oxygen section in hospital prescription charts

* Saturation is indicated in almost all cases except for palliat* Saturation is indicated in almost all cases except for palliative terminal care ive terminal care

DRUG OXYGEN(Refer To Trust Oxygen Policy)

Circle target oxygen saturation

88-92% 94-98% Other___

STOP DATE

Starting device/flow rate________

PRN / Continuous PHARM

Tick if saturation not indicated(Saturation is indicated in almost all cases except for palliative terminal care)

SIGNATURE / PRINT NAME DATEddmmyy

0808

1212

1818

2222

• 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

Oxygen prescriptionOxygen prescriptionand Administrationand Administration

Oxygen use in palliative careOxygen 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

DevicesDevices

• 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.

High Concentration Reservoir MaskHigh Concentration Reservoir Mask

• 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 inspiratoryflow and pattern of breathing.

• Comfortable and easily tolerated• No re-breathing• Low cost product• Preferred by patients (Vs simple mask)

Nasal Nasal CannulaeCannulae

Simple face maskSimple face mask(Medium concentration, (Medium concentration, variable performance)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)

VenturiVenturi or Fixed Performance Masksor Fixed Performance MasksAim to deliver constant oxygen concentrationwithin and between breaths.

24-40% Venturi Masks operate accurately60% Venturi mask gives ~50% FIO2

With TACHYPNOEA (RR >30/min) the oxygensupply should be increased by 50%

Increasing flow does not increase oxygen concentration

Operation of Operation of VenturiVenturi valvevalve

O2

O2

+Air

Air

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)

Standard Oxygen Therapy 1960s-2008

Acute Patients Stable Patients

Future oxygen therapy

Criticalillness

Most patients

Patients at risk of HypercapnicRespiratory Failure

What device and What device and flow rate should you flow rate should you

use in each use in each situation?situation?

Many patients need highMany patients need high--dose oxygen to dose oxygen to normalize saturationnormalize saturation

• Severe Pneumonia• Severe LVF• Major Trauma• Sepsis and Shock• Major atelectasis• Pulmonary Embolism• Lung Fibrosis • Etc etc etc

Critical illness requiring high levels of supplemental oxygen– see Table 1 and Section 8

Serious illness requiring moderate levels of supplemental oxygen if a patient is hypoxaemic – see Table 2 and Section 8

COPD and other conditions requiring controlled or low-dose oxygen therapy – see Table 3 and Section 8

Conditions for which patients should be monitored closely but oxygen therapy is not required unless the patient is hypoxaemic – see Table 4 and Section 8

Oxygen use in specific illnessesOxygen use in specific illnessesSee Tables 1-4 and Charts 1-2 in BTS Emergency Oxygen Guideline

Handouts of these tables and charts to be provided at training sessions

Is this patient at risk of hypercapnic respiratory failure

(Type 2 Respiratory Failure)?

YESTarget saturation is 88-92% whilst awaiting blood gas results

NO

Aim for SpO2 94-98%

Chart 1Oxygen prescription for acutely hypoxaemic patients in hospital

Specific instructions are given for each category of patient depending on blood gas results etc

Is the patient critically ill or in a peri-arrest

condition?

Commence treatment with reservoir mask or bag-valve

mask and manage as advised in Table 1

Yes

No

YesCHECK ABGs

Monitor SpO2. O2may not be required or be prescribed prn

No

SpO2 ≤ 93%

PCO2 < 6.0(Normal or

low)

PCO2 >6.0or patient tiring

Seek immediate senior review

Consider invasive ventilation

Treat appropriately aiming to keep SpO2 94-98%%

Seek immediate senior review

Consider NIV or invasive ventilation

Repeat ABG’s:If Respiratory Acidosis

( pH <7.35 & PCO2>6.0)Seek immediate senior review, consider NIV/ICU.Consider reducing FiO2if PO2 > 8.0 kPa

Treat urgently. Aim for SpO2 of 94-98% until immediate senior review. Also consider COPD needing SpO2 90-92%

Treat with the lowest strength Venturi mask that will keep SpO2between 88-92%

pH > 7.35and PaCO2 >6kPa

(Hypercapnia)

Treat with lowest FiO2 to keep SpO2 88-92% via Venturi mask pending senior medical advice or NIV or ICU admission

pH <7.35 and PCO2 > 6.0

(Respiratory Acidosis)

or patient tiring

Obtain ABGs

Treat appropriately aiming to keep SpO2 94-98%

YES(Risk of CO2Retention)

No known Risk of CO2 Retention

PATIENTS IN A PERI ARREST SITUATION AND CRITICALLY ILL PATIENTS SHOULD BE GIVEN MAXIMAL OXYGEN 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 EPR: keep saturation at 88-92% for this sub-group of patients)

All Patients must have ABG or Earlobe Blood Gases (ELBG)

within 1 hour of requiring increased

oxygen dose

Seek Medical Advice if patient appears to

need increasing oxygen therapy

or if there is a rising mEWS or Track and

Trigger score

FLOW CHART FOR OXYGEN ADMINISTRATION ON GENERAL WARDS IN HOSPITAFLOW CHART FOR OXYGEN ADMINISTRATION ON GENERAL WARDS IN HOSPITALSLSSee 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 saturationThe 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).

Once your patient has adequate and stable saturation on minimal oxygen dose, consider discontinuation of oxygen therapy

Venturi 24% 2-4 l/min*

Venturi 28% 4-6 l/min

Venturi 35% 8-10 l/min

Nasal cannulae 1 l/min

Nasal cannulae 2 l/min

Nasal cannulae 4 l/min

Venturi 40% 10-12 l/min or Simple Face Mask at 5-6 l/min

Venturi 60% 12-15 l/min or Simple Face Mask at 7-10 l/min

Reservoir Mask at 15 l/min Oxygen flow

Blue

White

Yellow

If Reservoir mask required, seek Senior Medical Input immediately

Red

Green

Signs of Respiratory Deterioration

• Respiratory rate(especially if >30)

• SpO2• oxygen dose needed

to keep saturation intarget range

• EWS/Trigger score• CO2 Retention

• Drowsiness• Headache• Flushed face• Tremor

Seek Medical Advice

*For Venturi masks, the higher flow rate is required if the respiratory rate is >30

Monitoring patientsMonitoring 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.

Respiratory Rate, Oxygen saturation and oxygen therapyClinical review required if saturation is outside target range

Continuous Oxygen / PRN / Not on oxygen therapy Target range: 88-92% 94-98% Other_____

Respiratory Rate

Respiratory Rate

Oxygen Saturation %

OxygenSaturation %

OxygenDevice or Air

OxygenDevice or Air

Oxygen flow rate L/min

Oxygen flow rate L/min

Your Initials*

Your Initials*

Model for respiratory section of observation chartModel for respiratory section of observation chart

Codes for recording oxygen delivery on observation chartA Air. (Patient not requiring oxygen therapy)AX Measurement on air for a patient who is on PRN Oxygen therapyAW Measurement on air for a patient who is being weaned off oxygen but not yet discontinued on chartN Nasal CannulaeSM Simple maskV24 Venturi 24% V28 Venturi 28% V35 Venturi 35% V40 Venturi 40% V60 Venturi 60%H28 Humidified oxygen at 28% (“Quatro” or similar device) (also H 35, H40, H60)RM Reservoir MaskTM Tracheostomy MaskCP Patient on CPAP systemNIV Patient on NIV systemOTH Other device

*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 (unless the oxygen prescription is part of a timed protocol

From the BTS Emergency Oxygen Guideline From the BTS Emergency Oxygen Guideline to the patientto the patient

• Guideline agreed by the whole medical community (endorsed by 21 Colleges and Societies)

• Medical and Nursing Champions in every Hospital Trust

• New prescription charts and monitoring charts in every hospital

• Training packages on BTS website

• Audit tools on BTS website www.brit-thoracic.org.uk

Summary Summary

1. Prescribe oxygen to a target saturation for each group of patients • 94 - 98% for most adult patients• 88 - 92% if risk of hypercapnia (or patient-specific target on alert card)

2. Administer oxygen to achieve target saturation

3. Monitor oxygen saturation and keep in target range

4. Taper oxygen dose and stop when stable

5. Audit your practice

6. All information on www.brit-thoracic.org.uk