Non-invasive Ventilation

1. Non-invasive Ventilation Dr Liam Doherty, Consultant Respiratory Physician, Bon Secours, Cork

3. Positive Airway Pressure CPAP = continuous positive airway pressure BiPAP= Bilevel positive airway pressure = Inspiratory pressure (IPAP) and expiratory pressure (EPAP)

4. Why?

5. Invasive ventilation • Sedated • Can’t speak • Can’t eat • High infection risk • Increased bleeding risk • Barotrauma • Limited ICU beds Non-invasive ventilation • Not sedated • Can speak • Can eat • Low infection risk • Available on well-supervised medical wards

6. How does it work?

9. In summary • Stents airway • Recruitment of alveoli • Decreases right to left intrapulmonary shunting • Decreases work of breathing • Overcomes PEEPi • Lowers left ventricular transmural pressure reducing afterload and increasing cardiac output

10. Who gets NIV? • Acute Type 2 Respiratory failure • COPD, pH <7.35 despite maximum Rx on controlled O2 • Cardiogenic pulmonary oedema with hypoxia. • Decompensated obstructive sleep apnoea. • Chest wall trauma who remain hypoxic. (CPAP) • Diffuse pneumonia who remain hypoxic despite maximum Rx (CPAP) • Weaning from invasive ventilation.

11. Who can’t have NIV? • Recent facial or upper airway/upper GI surgery, • Facial burns or trauma, • Fixed obstruction of the upper airway, • Vomiting. • Inability to protect the airway, • Copious respiratory secretions • Life threatening hypoxaemia, • Severe co-morbidity, • Confusion/agitation, • Bowel obstruction.

12. ? Which ventilator

13. Types of NIV • Negative pressure ventilation • e.g. “iron-lung”, tank, shell, cuirass, rocking bed, pneumo-belt • Positive pressure ventilation • Pressure limited (CPAP, Bilevel PAP) • Volume limited N.B. Diaphragm-pacing, glosso-pharyngeal breathing, cough insufflator-exsufflator

14. ? Which interface

15. How do you commence NIV?

17. Monitoring progress • Oximetry • Respiratory rate • Patient comfort • PCO2 • Patient-ventilator synchronisation Give breaks for drinks/food Keep on for as long as possible (2 days+)

18. When things go wrong!

19. Is ventilation inadequate? • Observe chest expansion • Increase target pressure (or IPAP) or volume • Consider increasing inspiratory time • Consider increasing respiratory rate (to increase minute ventilation) • Consider a different mode of ventilation/ventilator, if available

20. Is the patient synchronising with the ventilator? • Observe patient • Adjust rate and/or IE ratio (with assist/control) • Check inspiratory trigger (if adjustable) • Check expiratory trigger (if adjustable) • Consider increasing EPAP (with bi-level pressure support in COPD)

21. Downside to NIV • Horrendous to wear • Can’t talk • Can’t eat/drink • Can’t sleep • Agitation, claustrophobia • Poor synchrony • Delays intubation

22. Final messages • Give appropriate oxygen! • Non-invasive ventilators just blow air • Try to synchronise ventilator to patient i.e. ventilator should support normal ventilation • When in doubt use CPAP • NIV doesn’t work for everyone (30% failure rate) • Never forget need for intubation!