Electronic letters to:

Review:
Oscar Peñuelas, MD, Fernando Frutos-Vivar, MD, and Andrés Esteban, MD PhD
Noninvasive positive-pressure ventilation in acute respiratory failure
CMAJ 2007; 177: 1211-1218 [Abstract] [Full text] [PDF]
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Electronic letters published:

[Read eLetter] Re: Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure
John Joseph   (31 December 2007)
[Read eLetter] Noninvasive ventilation and aerosol transmissible infections
Vincenzo Puro   (29 November 2007)
[Read eLetter] Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure
Akashdeep Singh   (7 November 2007)

Re: Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure 31 December 2007
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John Joseph
Cancer Institute CMC

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Re: Re: Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure

john.parmod{at}gmail.com John Joseph

The use of NIV in immuno-compromised host especially in post-bone marrow transplant as highlighted by Dr Singh is highly appreciable. In our day to day practice we have seen that the timely (early) institution of NIV prevents intubation and mechanical ventilation and also the complications associated with invasive ventilation. This indication seems to have been under utilized globally as seems from the original review by Oscar et al.

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Noninvasive ventilation and aerosol transmissible infections 29 November 2007
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Vincenzo Puro
Istituto Nazionale Malattie Infettive L. Spallanzani

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Re: Noninvasive ventilation and aerosol transmissible infections

puro{at}inmi.it Vincenzo Puro

Authors: 1. Vincenzo Puro, MD, Epidemiological Department, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy. 2. Francesco Maria Fusco, MD, Epidemiological Department, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy. 3. Silvia Pittalis, MD, Epidemiological Department, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy. 4. Simone Lanini, MD, Epidemiological Department, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy. 5. Giuseppe Ippolito, MD, Scientific Director, National Institute for Infectious Diseases "L. Spallanzani", Rome, Italy.

Text: In their in-depth review on Noninvasive Ventilation (NIV) in acute respiratory failure1, the authors did not discuss the use of NIV in patients with infections transmissible through aerosol. The efficacy of NIV in those circumstances has not been adequately tested, but anecdotic reports and observational studies showed that NIV was successfully applied in patients with acute respiratory failure due to human-adapted avian influenza, aspergillosis, and varicella.2-4 Moreover, NIV was found to be able to avoid intubation in most Severe Acute Respiratory Syndrome (SARS) patients.5-7 Moreover, when critical care capabilities are overcome, such as during an influenza pandemic, NIV may be of value as a necessary alternative to, or at least as a bridge to invasive ventilation.8 Contrasting and often methodologically flawed data are available on the risk of transmission though aerosol to healthcare workers while performing NIV.9-12 Indeed, in the recently proposed WHO Interim Guidelines on prevention and control of acute respiratory diseases in health-care, NIV has been included among those aerosol-generating procedures in which the risk of pathogen transmission is still “controversial/possible” but not documented.13 Nevertheless, experiences from the field mostly showed the use of NIV to be safe, if appropriate precautions are taken5,6,11,14, as in the other aerosol-generating procedures: infected patients should be placed in adequate facilities and recommended personal protective equipments should be worn. Moreover to further reduce the risk of pathogens diffusion, exhalation ports that generate round- the–tube airflow6 and viral-bacterial filter interposed between the mask and the exhalation port are recommended.13

References: 1. Peñuelas O, Frutos-Vivar F, Esteban A. Noninvasive positive-pressure ventilation in acute respiratory failure. CMAJ 2007;177:1211-8. 2. Tran TH, Nguyen TL, Nguyen TD et al. Avian influenza A (H5N1) in 10 patients in Vietnam. N Engl J Med 2004;350:1179-88. 3. Antonelli M, Conti G, Bufi M et al. Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation: a randomized trial. JAMA 2000;283:235-41. 4. Sadovnikoff N, Varon J. CPAP mask management of varicella-induced respiratory failure. Chest 1993;103:1894-5. 5. Zhao Z, Zhang F, Xu M et al. Description and clinical treatment of an early outbreak of severe acute respiratory syndrome (SARS) in Guangzhou, PR China. J Med Microbiol 2003;52:715-20. 6. Wu W, Wang J, Liu P et al. A hospital outbreak of severe acute respiratory syndrome in Guangzhou, China. Chin Med J 2003;116: 811-8. 7. Yam LY, Chan AY, Cheung TM et al. Non-invasive versus invasive mechanical ventilation for respiratory failure in severe acute respiratory syndrome. Chin Med J 2005;118:1413-21. 8. British Infection Society; British Thoracic Society; Health Protection Agency. Pandemic flu: clinical management of patients with an influenza- like illness during an influenza pandemic. Provisional guidelines from the British Infection Society, British Thoracic Society, and Health Protection Agency in collaboration with the Department of Health. Thorax 2007;62 Suppl 1:1-46. 9. Fowler RA, Guest CB, Lapinsky SE et al. Transmission of severe acute respiratory syndrome during intubation and mechanical ventilation. Am J Respir Crit Care Med 2004;169:1198-202. 10. Levy MM, Baylor MS, Bernard GR et al. Clinical issues and research in respiratory failure from severe acute respiratory syndrome. Am J Respir Crit Care Med 2005;171:518-26. 11. Cheung TM, Yam LY, So LK et al. Effectiveness of noninvasive positive pressure ventilation in the treatment of acute respiratory failure in severe acute respiratory syndrome. Chest 2004;126:845-50. 12. Hui DS, Hall SD, Chan MT et al. Noninvasive positive-pressure ventilation: An experimental model to assess air and particle dispersion. Chest 2006;130:730-40. 13. World Health Organization. Infection prevention and control of epidemic- and pandemic-prone acute respiratory diseases in health care. WHO Interim Guidelines. Available: http://www.who.int/csr/resources/publications/WHO_CD_EPR_2007_6/en/ (accessed 2007 Nov 28). 14. So LKY, Lau ACW, Yam LYC, et al. Development of a standard treatment protocol for severe acute respiratory syndrome. Lancet 2003;361:1615-6.

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Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure 7 November 2007
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Akashdeep Singh
Christian Medical College and Hospital Ludhiana,India

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Re: Another Look at Noninvasive Positive-Pressure Ventilation in acute respiratory failure

drsinghakashdeep{at}gmail.com Akashdeep Singh

Oscar Peñuelas and colleagues, in this month’s issue of CMAJ, have nicely reviewed the acute applications of noninvasive positive-pressure ventilation (NPPV)1. However, the discussants do not mention about the role of NPPV in immunocompromised patients with acute respiratory failure, cystic fibrosis, upper airway obstruction and acute neuromuscular respiratory failure.

Immunosuppressed patients are at greater risk of developing serious nosocomial infections when ventilated through an invasive route. In a randomized trial of 40 solid organ transplants patient with HRF, Antonelli et al2compared NIV with facemask to standard treatment and found a significant reduction in rate of endotracheal intubation, fatal complications, length of stay in the ICU of survivors and ICU mortality. However, there was no difference in-hospital mortality. In another prospective RCT, by Hilbert and colleagues,3 52 immuno-suppressed patients (30 patients with hematological malignancies and neutropenia, 18 who received immunosuppression to prevent rejection of solid organ transplantation and four with HIV syndrome), were randomized to receive conventional medical treatment or NIV plus conventional treatment. Patients were recruited at an early stage of HRF. NIV significantly reduced the rate of intubation and serious complications. Both ICU and hospital mortality were significantly reduced. In this prospective RCT on immunocomprmised patients treated with NIV, authors obtained impressive results in the sub group of patients with hematological malignancies and neutropenia. With use of NIV Azoulay et al have shown improved survival in cancer patients. 4 Several studies support the use of NPPV therapy in patients with acute exacerbations of cystic fibrosis. Madden and collegues reported 5 their experience using NPPV in 113 cystic fibrosis patients who had experienced acute deteriorations. Of the 90 patients (median FEV1/FVC ratio, 0.5 L) who were either on or being evaluated for the lung transplant waiting list, 28 patients had successfully received lung transplantation and 10 others were still on the list. The authors noted that NPPV improved hypoxia but not hypercapnia. These case series suggest that NPPV is helpful as a rescue therapy in supporting acutely deteriorating cystic fibrosis patients, providing a bridge to transplantation. NPPV can be used to treat patients with upper airway obstructions such as that caused by glottic edema following extubation. In this situation, NPPV can be combined with aerosolized medication and/or heliox If therapy with NPPV is considered, patients should be selected with great caution and monitored closely because upper airway obstruction can lead to precipitous deteriorations. The inappropriate use of NPPV in patients with tight, fixed upper airway obstruction should be avoided so as not to delay the institution of definitive therapy. NIV has been successfully used in patients with acute on chronic respiratory failure and has been shown to decrease the need for invasive ventilation.6 The decision to use NIV in acute neuromuscular failure depends upon the severity of the ventilatory failure, the presence or absence of bulbar involvement, and the availability of other effective treatments—for example, in myasthenia gravis and Guillain-Barré syndrome. Patients with severe gas exchange abnormalities, bulbar involvement severe enough to compromise airway management are obvious contraindications; however, there is sparse clinical evidence on the choice of patients who are likely to benefit from NIV. BiPAP can be tried first in selected patients with acute respiratory failure especially due to myasthenic crisis and Guillain-Barré syndrome, while awaiting improvement from other specific therapies.

References

1. Oscar Peñuelas MD, Fernando Frutos-Vivar MD, Andrés Esteban MD PhD Noninvasive positive-pressure ventilation in acute respiratory failure. CMAJ 2007;177(10):1211-8

2. Antonelli M, Conti G, Bufi M, Costa MG, Lappa A, Rocco M, et al. Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation: A randomized trial. JAMA 2000;283:235-41.

3. Hilbert G, Gruson D, Vargas F, Valentino R, Gbikpi-Benissan G, Dupon M, et al. Noninvasive ventilation in immunosuppressed patients with pulmonary infiltrates, fever and acute respiratory failure. N Eng J Med 2001;344:481-7.

4. Azoulay E, Alberti C, Bornstsin C, Leleu G, Moreau D, Recher C, et al. Improved survival in cancer patients requiring mechanical ventilatory support: Impact of noninvasive mechanical ventilatory support. Crit Care Med 2001;29:519-25.

5. Madden BP, Kariyawasam H, Siddiqi AJ, et al. Noninvasive ventilation in cystic fibrosis patients with acute or chronic respiratory failure. Eur Respir J 2002; 19:310–313

6. Mayer SA. Intensive care of the myasthenic patient. Neurology 1997;48 (Suppl 5) :S70–75.

Conflict of Interest:

None declared