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Non-invasive ventilation

Up Dysynchrony e-lectures Figure 5a & 5b Modes of ventilation Non-invasive ventilation Physiological effects Specific ventilators

Charles Gomersall

Updated June 2006


Patient criteria

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

Underlying disease


  • 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


Patient interfaces

Variety of interfaces are available


  • 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 ̃ 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, April, 2014 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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