High VS Low Flow Nasal O2 for Acute Hypercapnic Respiratory Failure

High Flow Nasal Cannula Therapy for Initial Oxygen Administration in Acute Hypercapnic Respiratory Failure - A Comparison Study of Two Current Standards of Care

Chronic lung conditions such as smoking related lung damage lead to breathing fail. This results in accumulation of gases such as carbon-di-oxide in the body especially during periods of illness known as exacerbation.

Current management of carbon-di-oxide accumulation is administration of oxygen, nebulisers, antibiotics etc and if necessary, provide a tight fitting mask around the face to provide breathing support. If this fails, then a patient is placed on a mechanical ventilator. The tight fitting mask therapy is also called non-invasive ventilation and is used widely but patients acceptability of the therapy is limited.

Providing a high flow of air with some oxygen could potentially provide the same benefit of the non-invasive ventilation and may also be better accepted by patients.

Currently the knowledge and evidence from studies suggest a beneficial role for this high flow therapy but this has not been investigated in well designed studies.

In the proposed study we aim to investigate whether use of the high flow therapy reduces the need for non-invasive ventilation in patients who present with a recent onset accumulation of carbon-di-oxide in their body due to long-term lung disease. If this shows benefit, it will lead to a bigger trial with patient benefiting by reduction in the non-invasive ventilation or indeed a need for an invasive breathing machine.

Inclusion Criteria:

1. Adult patients > 18 years of age
2. Acute Hypercapnic respiratory failure with pH < 7.35 and pCO2 > 6 KPa

Exclusion Criteria:

1. Age < 18 years
2. Pregnant or Breast-Feeding
3. Patient cannot read and understand English
4. Hypercapnia secondary to a drug toxicity or non-pulmonary aetiology
5. Hypercapnia secondary to exacerbation of asthma
6. Contraindication to NIV
7. Contraindication to HFNC
8. Not for escalation to NIV
9. pH < 7.15
10. GCS 8 or less
11. Shock defined as systolic < 90 mmHg or a reduction by 20mmHg from usual systolic BP despite volume resuscitation
12. Respiratory or cardio-respiratory arrest
13. Any other indication that requires immediate invasive/non-invasive mechanical ventilation