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Technical practices are important to consider when assessing noninvasive ventilation failure

Pulmonary and Respiratory Intensive Care Unit, Hopital de Bois-Guillaume, Rouen University, Rouen, France

To the Editors:

In their recent publication in the European Respiratory Journal, Confalonieri et al. 1 nicely describe relevant clinical predictive factors of noninvasive ventilation (NIV) failure in chronic obstructive pulmonary disease patients hospitalised for acute hypercapnic respiratory failure. The authors provide an interesting tool that could help to quantify this risk better and, thus, shorten the delay of a possible intubation.

NIV failures are linked to the clinical severity at admission and to the location where it was performed, as confirmed by the authors, who focused their work on clinical determinants of immediate NIV failure. However, technical factors, which are more difficult to assess, may modify the results of such prognostic studies, even if they are performed by experienced personnel. Recommendations and experts' opinions concerning NIV in the acute setting 2–4 mention the fact that a proportion of patients fail NIV because of technical problems related to humidification, interfaces, ventilatory modes and patient–ventilator interactions 4.

Humidification of inspired air is a critical factor, since heat and moisture exchangers increase the work of breathing and may lead to NIV failure 5, 6. NIV failure may also be linked to a poor adaptation to nasal/facial masks, leading to asynchrony and/or unintentional leaks. In real world studies, most teams change the interface during the ventilatory course, using facial masks to reduce leaks and, as soon as possible, nasal masks to improve tolerance 7. Finally, it would be interesting to know if the pressure support mode was modified or shifted during NIV courses in this study. A shift from pressure support to assist–control ventilation is mentioned by some authors in the literature 8, and this could help to resolve some situations, avoiding endotracheal intubation.

In addition to clinical parameters at admission, technical practices obviously need to be taken into account when assessing noninvasive ventilation success or failure during an acute hypercapnic respiratory failure episode. It is, of course, extremely difficult to design clinical studies that would control all technical factors, and we do not know to what extent such control would have modified the final message from Confalonieri et al. 1. However, since a non-negligible percentage of patients with chronic obstructive pulmonary disease and acute hypercapnic respiratory failure still fail to be successfully treated by noninvasive ventilation, the important results from Confalonieri et al. 1 would need to be extended in a prospective study assessing the role of technical factors in the outcome of acute hypercapnic respiratory failure.

REFERENCES

1. Confalonieri M, Garuti G, Cattaruzza MS, et al. A chart of failure risk for noninvasive ventilation in patients with COPD exacerbation. Eur Respir J 2005;25:348–355.[Abstract/Free Full Text]
2. British Thoracic Society Standards of Care Committee. Non-invasive ventilation in acute respiratory failure. Thorax 2002;57:192–211.[Free Full Text]
3. Nava S, Ceriana P. Causes of failure of noninvasive mechanical ventilation. Respir Care 2004;49:295–303.[Medline] [Order article via Infotrieve]
4. Sinuff T, Keenan SP. Clinical practice guideline for the use of noninvasive positive pressure ventilation in COPD patients with acute respiratory failure. J Crit Care 2004;19:82–91.[Medline] [Order article via Infotrieve]
5. Lellouche F, Maggiore SM, Deye N, et al. Effect of the humidification device on the work of breathing during noninvasive ventilation. Intensive Care Med 2002;28:1582–1589.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]
6. Jaber S, Chanques G, Matecki S, et al. Comparison of the effects of heat and moisture exchangers and heated humidifiers on ventilation and gas exchange during non-invasive ventilation. Intensive Care Med 2002;28:1590–1594.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]
7. Navalesi P, Fanfulla F, Frigerio P, Gregoretti C, Nava S. Physiologic evaluation of noninvasive mechanical ventilation delivered with three types of masks in patients with chronic hypercapnic respiratory failure. Crit Care Med 2000;28:1785–1790.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]
8. Girault C, Briel A, Hellot MF, et al. Noninvasive mechanical ventilation in clinical practice: a 2-year experience in a medical intensive care unit. Crit Care Med 2003;31:552–559.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Cuvelier, A. Articles by Muir, J-F. Search for Related Content PubMed PubMed Citation Articles by Cuvelier, A. Articles by Muir, J-F.