1. BTS/ICS Guidelines for the ventilatory management of acute hypercapnic respiratory failure in adults
British Thoracic Society
Intensive Care Society

2. Introduction
Acute Hypercapnic Respiratory Failure (AHRF) results in 50,000 admissions each year in the UK
Without ventilatory support AHRF is associated with a high mortality rate and a prolonged inpatient stay
The incidence of AHRF is similar to upper GI haemorrhage which is, quite rightly, recognised as a medical emergency and one in which delay in instituting treatment and poor coordination between clinical teams increases mortality

3. Introduction Patients with AHRF are not receiving optimal therapy:
BTS NIV audit reports
Acidosis, non-invasive ventilation and mortality in hospitalised COPD exacerbations. Thorax 2011
National COPD Audit Programme: secondary care clinical audit report: “Who Cares Matters 2014”
“provision of NIV is often poorly performed, patients not treated until acidosis severe and some patients inappropriately denied admission to the ICU”

4. Aims of Guideline
Highlight current suboptimal care for individuals with AHRF in the UK
Review the evidence base for treatment of AHRF by invasive and non invasive ventilation
Promote an integrated AHRF care pathway involving Emergency Departments, Medical Admission Units, Respiratory Wards & Critical Care
Improve patient outcome and experience

5. AHRF
May complicate a number of conditions that affect lungs and/or impair the function of respiratory pump
Airway disease : COPD, asthma, Cystic fibrosis and non-CF bronchiectasis
Respiratory pump : neuromuscular disease, chest wall deformity and morbid obesity
AHRF may be acute or acute on chronic

6. Acute exacerbations COPD
Commonest cause of AHRF : 20% AECOPD
In COPD signals advanced disease, high risk of future hospitalisations and limited long term prognosis
In COPD mortality 8% without AHRF and up to 30% with AHRF depending on the degree of acidosis

7. In all causes AHRF
Development of AHRF warrants a change in future care arrangements:
predicts future life threatening episodes
indicates need, in some, for domiciliary NIV

8. Treatment of AHRF Prior to availability of non-invasive ventilation:
intubation was required when conventional treatment failed
unclear what criteria guided recognition of this need …...intubation variably offered internationally……limited availability of intensive care beds in UK reduced access to this option

9. Prognostic indicators
Mostly investigated in AECOPD, where outcome less good in those with adverse features, especially when multiple
Medical staff infrequently use formal severity scoring and consistently under-estimate survival potential
Scoring poorly predictive on individual basis and, on its own, little help in deciding when mechanical ventilation would be futile
Important that potentially life-saving treatment, including NIV, not inappropriately withheld

10. Recommendations (1): Prevention AHRF
Oxygen should be used with care in all individuals at risk of AHRF
Use a target oxygen saturation range of 88-92% in ALL self-ventilating patients at risk of AHRF
If oxygen indicated, start at 24-28% oxygen via a Venturi mask

11. Recommendations (2): NIV
Consider starting NIV when pH < 7.35, PCO2 > 6.5 kPa and respiratory rate > 23  
Consider starting NIV in hypercapnic NMD or CWD patients in the absence acidosis  
NIV should not be used in acute hypercapnic asthma 
Do not delay starting NIV or continue with it when the patient is deteriorating as both increase mortality.

12. Recommendations (3): Invasive Ventilation
The use of NIV should not delay escalation to IMV when this is more appropriate
Intubation is indicated if NIV is failing (unless it is not desired by the patient or agreed not in his/her “best interest”)
Be aware that clinicians can underestimate survival potential in AHRF treated by IMV

13. Recommendations (4): NIV in the ICU
Patients with higher risk of NIV failure can be predicted and should be considered for direct admission to ICU
In many AHRF patients the planned use of NIV post extubation reduces the need for re-intubation
In COPD, and in many individuals with NM disease, NIV-supported extubation should be employed in preference to inserting a tracheostomy

14. Recommendations (5): Organisational aspects
Be aware:
A care environment with level 2 equivalence improves the outcome of NIV
Ward-based NIV risks greater delay in expert review and/or escalation to IMV
Coordination of care between the ICU and other patient areas improves outcome

15. Recommendations (6): Governance and risk avoidance
Care planning is needed between respiratory, emergency and acute care physicians and the ICU
A senior clinician should lead in the local production of a seamless AHRF patient pathway
Episodes of oxygen toxicity, or unexpected death whilst on NIV, should be critically reported
Rolling programmes of staff training and auditing of performance in AHRF improves outcomes

16. Figure 1 Summary for providing acute NIV

17. Figure 2 Guide to initial settings and aims with imv

18. Figure 3: The three phases of patient management in AHRF

19. Further information
The guideline can be found on the BTS website at: Contact: