Critically evaluate the role of non-invasive ventilation (NIV) in critically ill patients.
Answer and interpretation
NIV provides ventilatory support for patients with respiratory failure via a sealed face-mask, nasal mask, mouthpiece, full face visor or helmet without the need for intubation. Ventilatory support may be with CPAP or bi-level modes and delivered by a range of ventilators from specifically designed devices to full-service ICU ventilators.
NIV decreases resource utilisation compared with invasive ventilation and avoids the associated complications.
Patient selection and a well-designed clinical protocol are important to avoid delaying intubation in patients who are not suitable for and/or failing NIV.
- APO – alveolar recruitment, decreased afterload, decreased work of breathing
- COPD – decrease work of breathing and unload respiratory muscles Immunosuppressed
- Planned strategy post extubation in selected patients
- OSA / Obesity hypoventilation syndrome
- Patients with not for intubation/ treatment limitation orders who may qualify for HDU admission or admission to respiratory care units
- Post-operative patients – in selected patients
- Rib fractures
- Cystic fibrosis as bridge to transplantation
Evidence for its use:
- APO – studies show decreased intubation rate and faster time to resolution of respiratory failure and reduction in mortality and hospital length of stay
- COPD – RCTs and Cochrane review (14 RCTs) showed significant improvement in intubation rates, complications, length of hospital stay and mortality rates for NIV compared with invasive ventilation
- Immunocompromised – – 2 studies, one looking at solid organ transplant recipients and one looking at patients with haematological malignancy showed benefit with NIV, i.e. fewer intubations, complications and reduced ICU and hospital mortality
- Asthma – probably beneficial but limited evidence
- Rib fractures – fewer episodes of pneumonia but no mortality benefit and limited evidence
Evidence against its use:
- Use as rescue strategy for failed extubation – delays time to re-intubation. May be of benefit as part of weaning strategy and planned intervention post extubation especially in COPD patients
- ARDS – not recommended as first line therapy
Predictors of success
- Younger age
- Unimpaired conscious state
- Moderate rather than severe hypercarbia
- Rapid improvement in physiological parameters
- Cardiac / respiratory arrest
- Cardiac instability – shock, ventricular dysrhythmias, severe acute myocardial ischaemia GI bleeding
- Intractable vomiting
- Inability to protect airway – poor cough, excessive secretions, decreased conscious state Upper airway obstruction
- Following upper GI surgery (some debate about this)
- Facial and nasal trauma and pressure sores
- Gastric distension
- Dry mucous membranes
- Aspiration of gastric contents
- Invasive ventilation
- HFNP – may provide CPAP 5mm Hg
Summary statement / My Practice
Role of NIV in critically ill includes APO and respiratory failure in COPD and immunosuppressed patients. In my practice I use NIV as a planned strategy post-extubation in selected patients and as ventilatory support for patients with respiratory failure and treatment directives limiting care. I do allow its use to delay or withhold intubation in those who need this.
- Pass rate: 60%
- Highest mark: 8.5
Examiner’s additional comments:
- NIV is a fundamental part of intensive care practice and the overall level of understanding was poor. Few candidates were able to demonstrate detailed knowledge of this core therapy.
- Candidates were not expected to include as much detail to score good marks. Essential points included indications, some mention of evidence for and against, contra-indications and complications. Candidates were given credit if they included valid points not in the answer template.
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.