BTS/ICS Guidelines for the ventilatory management of acute hypercapnic respiratory failure in adults British Thoracic Society Intensive Care Society
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
Introduction Patients with AHRF are not receiving optimal therapy: BTS NIV audit reports 2011-13 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 https://www.rcplondon.ac.uk/projects/nationalcopd-audit-programme provision of NIV is often poorly performed, patients not treated until acidosis severe and some patients inappropriately denied admission to the ICU
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
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
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
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
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
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
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
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.
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
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
Be aware: Recommendations (5): Organisational aspects 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
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
Figure 1 Summary for providing acute NIV
Figure 2 Guide to initial settings and aims with imv
Figure 3: The three phases of patient management in AHRF
Further information The guideline can be found on the BTS website at: https://www.brit-thoracic.org.uk/guidelines-andquality-standards/ventilatory-management-ofacute-hypercapnic-respiratory-failure-guideline/ Contact: bts@brit-thoracic.org.uk