GGC Medicines


Adult Therapeutics Handbook

Non-Invasive Ventilation (NIV) Protocol in COPD

Non-Invasive Ventilation (NIV) Protocol in COPD

AIM = To ensure patients are correctly and promptly identified as candidates for NIV.

Step 1

  • History
  • Examination
  • CXR
  • Arterial Blood Gases (ABGs)
  • Establish the premorbid functional status of the patient if possible as this may influence subsequent decisions regarding suitability for management in higher dependency / intensive care settings.
  • Establish what the patient’s wishes would be regarding the use of NIV or transfer to intensive care - there may be an advanced directive in place, or they may express the wish not to receive NIV / ICU ventilation in the event of deterioration if they are initially stable enough to have this conversation.

Is the patient a candidate for NIV?

  • Does the patient have a diagnosis of COPD?
  • Does the patient have an acidotic exacerbation of COPD?
  • If 'NO' to either of the above then discuss with senior medical staff suitability for NIV.
  • Physiological criteria: decompensated type 2 respiratory failure i.e. pH <7.35 (H+ >45nmol/L) and pCO2 >6kPa.
  • On maximum medical therapy (and has been for 1 hour), nebulised salbutamol when required, corticosteroids, antibiotics if appropriate, controlled FiO2 (usually 28% venturi mask - aim for O2 saturation 86-90%), and reversal of respiratory depressants.
  • Moderate to severe dyspnoea, RR >25bpm.

Step 2 - Are there any contraindications to NIV?

Absolute contraindications:

  • Respiratory arrest / need for immediate intubation
  • Facial trauma / burns / surgery / abnormalities
  • Fixed upper airway obstruction
  • Severe vomiting
  • Acute severe asthma
  • Pneumothorax (unless chest drain inserted)
  • Confirmed wish by the patient not to receive NIV in the event of a deterioration.

Relative contraindications:

  • Inability to protect airway
  • Life-threatening hypoxaemia
  • Haemodynamic instability
  • Impaired consciousness
  • Confusion / agitation
  • Bowel obstruction
  • Recent facial / upper airway or upper GI tract surgery
  • Copious respiratory secretions
  • Pneumonia

(NIV may be used despite 'relative contraindications' if this is the 'ceiling' of treatment and the patient is not for ICU / intubation.)

Step 3 - Patient for ICU / intubation?

Step 4 - Initiation of NIV

AIM = To ensure patients are correctly and safely initiated on NIV.

Arterial blood gases must be checked prior to starting NIV and whilst the patient is on controlled FiO2.

  1. Size for face mask (select the smallest mask that fits comfortably):
    • small leaks are permitted but not into the eyes.
    • assess mask fit by monitoring mask leak, aim to keep any leaks to a minimum.
    • demonstrate use of quick release strap.
    .
  2. Position the patient in bed or chair at >30Oangle.
  3. Set ventilator settings:
    • IPAP = 10cm H2O.
    • EPAP = 4cm H2O.
    • RATE = 12bpm (becomes active should patient stop breathing or have periods of apnoea).
    • EXPIRATION TRIGGER = 2.
    • INSPIRATION TRIGGER = 2.
    • RISE TIME = 1.
    • OXYGEN = if supplementary oxygen required, set at 4L/min and titrate as necessary to maintain SpO2 88-92%.
  4. Increase IPAP in increments of 2cm H2O to the maximum that patient will tolerate (usually not more than 20cm H2O).

Step 5 - Monitoring the patient on NIV

Record observations on NIV Observation Chart every 15 minutes for the first hour, evaluate thereafter:

  • SpO2 - continuous monitoring with pulse oximeter.
  • ABGs - 1 hour post commencement of NIV, thereafter evaluate as per patient's condition (if ABGs worsening after 4-6 hours then this is a poor prognostic factor for NIV).
  • Respiratory rate.
  • Heart rate.
  • Evaluate accessory muscle use.
  • Chest wall movement (to ensure adequate ventilation).
  • Synchrony with the ventilator and air leaks.

Step 6 - Treatment failure

  • Indications of failure:
    • No improvement in acidosis
    • No improvement in CO2
    • No reduction in respiratory rate
    • Patient not tolerating
    • Patient refusal
  • If patient is not tolerant of, or refuses NIV, rediscuss management with senior medical staff.
  • If ceiling of treatment and NIV fails, refer to the Palliative Care Guidelines.
  • Ensure documentation of patient and family views.

Step 7 - Weaning criteria

Is the patient ready to wean?

  • Clinically stable for >6 hours
  • RR <24bpm
  • HR <110bpm
  • H+ <45nmol/L
  • SpO2 >88% on 4L O2 whilst on NIV

If 'NO' to the above:

  • Continuous NIV (monitor as before)

If 'YES' to the above:

  • Allow breaks for meals, medication, physiotherapy etc
  • Consider nocturnal NIV only
  • Controlled O2 therapy

If worsening respiratory distress, reassess patient, review therapy and consider recommencing NIV.

Patients on home NIV

Some patients use NIV chronically at home. Typical reasons are:

  • Chronic hypercapnic respiratory failure:
    • obesity hypoventilation
    • chest bellows disease
    • neuromuscular disease
    • occasionally COPD
  • Palliation in motor neurone disease (MND / ALS)

The local respiratory unit should be involved early in the care of these patients.

 

Contents last reviewed June 2019