Non-invasive ventilation

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Updated June 2006

• conscious, cooperative and breathing
• intact laryngeal reflexes
• haemodynamic stability

Underlying disease

COPD

• early NIV to prevent development of respiratory distress and ventilatory failure is ineffective
• acute hypercapnic respiratory failure. NIV reduces the rate of intubation, reduces complications and lowers mortality

Cardiogenic pulmonary oedema

• improves oxygenation in most patients
• recent systematic review suggests that CPAP reduces hospital mortality (relative risk of death 0.59) but bilevel positive airway pressure does not
  • may be a reflection of the low level of PEEP (≤ 5 cm H₂O) used in the studies examining the effect of BiPAP
  • same study also suggested that BiPAP is associated with a higher risk of myocardial infarction than standard therapy

Acute hypoxaemic respiratory failure

• immunocompromised patients with pulmonary infiltrates and fever and mild respiratory failure
  • decreases mortality
• pneumonia
  • appears to reduce mortality and need for intubation
  • benefit greatest in hypercapnic patients
• ARDS
  • meta-analyses suggest that NIPPV only delays need for intubation but has no beneficial effect on outcome
• severe hypoxaemic respiratory failure
  • single study in an centre with large experience demonstrated a trend to lower mortality and morbidity in NIV group compared to patients who were invasively ventilated

Weaning

• Shortens duration of mechanical ventilation in patients with chronic respiratory disorders
• Decreases risk of re-intubation in patients who successfully complete a T-piece trial but are at high risk of reintubation
• Associated with increased mortality when used as "rescue" therapy for patients who develop respiratory failure soon after extubation

Patient interfaces

Variety of interfaces are available

• nasal mask
  • tends to be better tolerated but less improvement in gas exchange
• oronasal mask
• full face mask
• helmet

• mask: leaks/mouth breathing, ulceration of bridge of nose (apply artificial skin prophylactically), mask dead space
• gastric distension: only a problem until patient learns to coordinate breathing and laryngeal movements
• dryness of nose/rhinorrhoea
• acceptance/synchronisation: rarely a problem if patient awake
• leak may Þ increase inspiratory time in flow-cycled pressure support mode. May be necessary to change to pressure preset assist control or add inspiratory time limit (eg 1.5 sec). Consider lowering pressure if leak not ¯ by adjusting or changing mask (have a variety of masks available).

Further reading

Nava S, Navalesi P, Conti G. TIme of non-invasive ventilation. Intensive Care Med, 2006, 32:361-370

Peter JV, Moran JL, Phillips-Hughes J, Graham P, Bersten AD. Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis. Lancet 2006; 367: 1155–1163.

Esteban A, Frutos-Vivar F, Ferguson ND, Arabi Y, Apezteguia C, Gonzalez M et al. Noninvasive positive-pressure ventilation for respiratory failure after extubation. N Engl J Med 2004; 350(24):2452-2460.

Keenan SP, Powers C, McCormack DG, Block G. Noninvasive positive-pressure ventilation for postextubation respiratory distress: a randomized controlled trial. JAMA 2002; 287(24):3238-3244.

Ferrer M, Valencia M, Nicolas JM, Bernadich O, Badia JR, Torres A. Early noninvasive ventilation averts extubation failure in patients at risk. A randomized trial. Am J Respir Crit Care Med 2006;173:164–170

©Charles Gomersall, October, 2009 unless otherwise stated. The author, editor and The Chinese University of Hong Kong take no responsibility for any adverse event resulting from the use of this webpage.
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