Indications for nasal or Full face NIV
Hypercapnic respiratory failure during an acute exacerbation of COPD with:
- Arterial pH <7.35.
- Arterial PaCO2 >6kPa (if acute onset).
- Tachypnoea >23 breaths/min.
- Acute hypercapnoeic respiratory failure (e.g. in acute exacerbations of COPD).
- Cardiogenic pulmonary oedema.
- Respiratory failure in immunocompromised patients (e.g. pneumonia).
- Neuromuscular disorders (respiratory failure).
- Asthma (NB selected cases only - decision by Respiratory Physician).
- Facial trauma/burns.
- Recent facial, upper airway or upper GI tract surgery.
- Fixed obstruction of the airways.
- Inability to protect airways or excessive airway secretions.
- Life threatening hypoxaemia.
- Undrained pneumothorax.
- Impaired consciousness or confusion/agitation.
- Full medical assessment.
- Arterial blood gases (ABG): pH 7.25 – 7.35; high PaCO2.
- Optimal medical treatment not successful.
- Consider commencing NIV.
- Have a plan for if NIV fails.
- Good outcome predicted if improvement in pH, PaCO2 and respiratory rate after 1hr of NIV.
- ?Chance of failure – high Apache score, poor nutritional status, confusion/impaired consciousness.
- Inform ITU of decision to commence NIV.
Setting Up (Bipap Focus)
- Consultant/Senior Decision maker to commence NIV.
- NIV machine (Bipap Focus in CUH) + tube + CO2 exhalation port + mask + head-cap.
- On the Bipap focus machine, the O2 tubing can be attached into the port on the face mask or beside the exhalation port.
- Set EPAP at 4 – 5 cm H2O and IPAP at 10 cm H2O.
- Set back-up breathing frequency to 8 – 10 breaths/minute.
- Select appropriate size mask (full face in preference to nasal) to fit patient.
- Explain procedure to patient.
- Hold mask in place to allow patient to familiarize themselves.
- Attach pulse oximeter.
- Commence NIV, holding mask in place initially.
- Secure mask in place with straps/headgear to prevent leaks – do not attach too tightly!
- Reassess patient after a few minutes.
- Check for leaks and refit mask if necessary.
- Add O2 to maintain SpO2 >85%.
- Instruct patient how to remove the mask and summon help.
- Increase IPAP gradually up to about 12 - 15 cmH2O over 1 hr.
- Clinical assessment and, if appropriate, check ABG at 1 hour.
- If procedure fails, institute alternative management plan.
COPD Patients in Mercy University Hospital
In MUH, COPD (in contrast to LVF patients) can be non-invasively ventilated using the guidelines shown right.
- Commence BiPAP at IPAP 10cm H20 / EPAP 4cm H20.
- Increase FiO2 to improve O2 saturation to >90%.
- Repeat ABG after 1 hr of NIV treatment.
- Titrate IPAP
- if pH<7.35, respiratory rate >25/min, PaCO2>6 kPa or persistent use of accessory muscles.
- Titrate EPAP.
- if persistent hypoxia.
- Titrate in increments of 2cm H20 to peak IPAP 20 / EPAP 8.
- Repeat ABG after 4 hrs of NIV; titrate pressures as above.
- NIV should be used for a minimum of 16 hours / 24 hours initially, reducing to 12 hours on Day 2, and 8 hours on Day 3 as the clinical setting permits.
Full ventilation reconsidered if:
- Arterial pH<7.2.
- Arterial pH 7.2 - 7.25 on two occasions 1 hr apart.
- Hypercapnic coma GCS <8 and PaCO2>8 kPa).
- PaO2<6 kPa despite maximum tolerated FiO2.
- Cardiorespiratory arrest.
- Is medical treatment optimal?
- Is physiotherapy needed (particularly for sputum retention)?
- What complications have developed (beware PTX or aspiration etc.)
- Check the pressures actually being achieved ( visible on the screen of the Bipap Focus).
- If PaCO2 remains high
- To much O2? Maintain SpO2 between 85% to 90%
- Excessive mask leakage?
- Is circuit set up correctly?
- Is patient synchronising with ventilator – adjust breathing rate and/or inspiratory and/or expiratory trigger
- Is re-breathing occurring? - Check patency of expiratory valve (if fitted). Consider increasing EPAP
- Is ventilation adequate – ?increase IPAP (increments of 2cm H2O to alleviate resp distress)
- If PaCO2 improves but PaO2 remains low
- Increase FiO2
- Consider increasing EPAP by increments of 2cm H2O. NB keep difference betw. IPAP and EPAP ≥ 6 cmH2O - so you may need to also increase IPAP.
Aims of NIV
- Deal with acute phase of respiratory failure.
- Attempt to stabilise patient’s condition.
- Contact ITU Registrar prior to transfer to medical ward.
- Treatment failure warrants ITU admission.
- Disposable masks and exhalation ports should be disposed of.
- Headgear should be washed in a washing machine – be careful with the Velcro straps.
- Use a bacterial filter between the tube and the BiPaP machine to reduce contamination risk to machine.
- 2008 (October) BTS GUIDELINE. Non-invasive ventilation - COPD
- CUH policy on NIV (abbreviated version) April 2015
- Print copy (PDF) instructions setting up BiPAP Focus NIV machine
- Setting up Nippy 3 NIV machine (print (PDF) version)