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Backup Respiratory Rate During Noninvasive Positive Pressure Ventilation in Obesity Hypoventilation SyndromeNoninvasive Positive Pressure Ventilation: Can This Difficult Puzzle Be Resolved? FREE TO VIEW

Antonio M. Esquinas, MD, PhD
Author and Funding Information

From the Intensive Care Unit, Hospital Morales Meseguer.

Correspondence to: Antonio M. Esquinas, MD, PhD, Intensive Care Unit, Hospital Morales Meseguer, Avenida Marques de los Velez s/n, Murcia, 30008 Spain; e-mail: antmesquinas@gmail.com


Financial/nonfinancial disclosures: The author has reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2013;143(4):1182-1183. doi:10.1378/chest.12-2408
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Published online
To the Editor:

Obesity hypoventilation syndrome (OHS) refers to sleep-related hypoventilation with repetitive episodes of complete and partial obstructions of the upper airway.1 Some finesse is required to determine the appropriate ventilator settings to prevent such episodes, which can alter the efficacy of noninvasive positive pressure ventilation (NPPV).

In a recent article in CHEST (January 2013), Contal et al2 analyzed the effects of three strategies: a spontaneous (S) mode, a low backup respiratory rate (BURR), and a high BURR. The S mode was worse than the S/T mode, and changing the BURR from an S/T mode with a high or low BURR to an S mode was associated with the occurrence of a highly significant increase in respiratory events and oxygenation desaturation index events.

It is worth highlighting some features of this study, which help place the findings in context. First, the population selected had some interesting characteristics. The prior use of NPPV for at least 42.7 months (duration of NPPV) and a baseline BURR of 14 may have influenced the results. Specifically, patients who had already been acclimated to NPPV might have adjusted more easily to a range of BURR. Second, a high BMI of 48.5 kg/m2 could also have reduced the efficacy of NPPV, making it difficult to generalize from these results to the entire spectrum of OHS.3

Third, the authors did not consider the potential effects of upper airway obstruction during sleep (obstructive apneas and hypopnea), which are common in severely obese patients and could further reduce the therapeutic efficacy,4 depending on the algorithm for setting the expiratory pressure. Fourth, it is difficult to determine the effect of the NPPV strategy on PaCO2 over the relatively short period of intervention in this study in the group that was not hypercapnic at baseline (pH, 7.44; PCO2, 41.3; bicarbonate, 28.1). Other outcomes would be required to assess the acute effects of NPPV in this group (Table 1 in Contal et al2).

Fifth, the oxygenation desaturation index was higher during periods of S-mode NPPV as compared with the S/T mode with low BURR and the S/T mode with high BURR (Table 2 in Contal et at2).4 It is possible that several factors could have accounted for these findings, including decreased lung volume and hypoventilation during sleep, especially in patients with a markedly elevated BMI.5

Finally, this study did not characterize conventional parameters describing patient/ventilatory asynchrony.6 I believe that the BURR is an important tool for treating hypoventilation in OHS. Further studies are necessary to establish best practices to maintain adequate ventilatory support and to achieve long-term outcomes.

References

Berry RB, Chediak A, Brown LK, et al;; NPPV Titration Task Force of the American Academy of Sleep Medicine NPPV Titration Task Force of the American Academy of Sleep Medicine. Best clinical practices for the sleep center adjustment of noninvasive positive pressure ventilation (NPPV) in stable chronic alveolar hypoventilation syndromes. J Clin Sleep Med. 2010;6(5):491-509. [PubMed]
 
Contal O, Adler D, Borel J-C, et al. Impact of different backup respiratory rates on the efficacy of noninvasive positive pressure ventilation in obesity hypoventilation syndrome: a randomized trial. Chest. 2013;143(1):37-46. [PubMed]
 
Janssens JP, Metzger M, Sforza E. Impact of volume targeting on efficacy of bi-level non-invasive ventilation and sleep in obesity-hypoventilation. Respir Med. 2009;103(2):165-172. [CrossRef] [PubMed]
 
Heinemann F, Budweiser S, Dobroschke J, Pfeifer M. Non-invasive positive pressure ventilation improves lung volumes in the obesity hypoventilation syndrome. Respir Med. 2007;101(6):1229-1235. [CrossRef] [PubMed]
 
Guo YF, Sforza E, Janssens JP. Respiratory patterns during sleep in obesity-hypoventilation patients treated with nocturnal pressure support: a preliminary report. Chest. 2007;131(4):1090-1099. [CrossRef] [PubMed]
 
Fanfulla F, Taurino AE, Lupo ND, Trentin R, D’Ambrosio C, Nava S. Effect of sleep on patient/ventilator asynchrony in patients undergoing chronic non-invasive mechanical ventilation. Respir Med. 2007;101(8):1702-1707. [CrossRef] [PubMed]
 

Figures

Tables

References

Berry RB, Chediak A, Brown LK, et al;; NPPV Titration Task Force of the American Academy of Sleep Medicine NPPV Titration Task Force of the American Academy of Sleep Medicine. Best clinical practices for the sleep center adjustment of noninvasive positive pressure ventilation (NPPV) in stable chronic alveolar hypoventilation syndromes. J Clin Sleep Med. 2010;6(5):491-509. [PubMed]
 
Contal O, Adler D, Borel J-C, et al. Impact of different backup respiratory rates on the efficacy of noninvasive positive pressure ventilation in obesity hypoventilation syndrome: a randomized trial. Chest. 2013;143(1):37-46. [PubMed]
 
Janssens JP, Metzger M, Sforza E. Impact of volume targeting on efficacy of bi-level non-invasive ventilation and sleep in obesity-hypoventilation. Respir Med. 2009;103(2):165-172. [CrossRef] [PubMed]
 
Heinemann F, Budweiser S, Dobroschke J, Pfeifer M. Non-invasive positive pressure ventilation improves lung volumes in the obesity hypoventilation syndrome. Respir Med. 2007;101(6):1229-1235. [CrossRef] [PubMed]
 
Guo YF, Sforza E, Janssens JP. Respiratory patterns during sleep in obesity-hypoventilation patients treated with nocturnal pressure support: a preliminary report. Chest. 2007;131(4):1090-1099. [CrossRef] [PubMed]
 
Fanfulla F, Taurino AE, Lupo ND, Trentin R, D’Ambrosio C, Nava S. Effect of sleep on patient/ventilator asynchrony in patients undergoing chronic non-invasive mechanical ventilation. Respir Med. 2007;101(8):1702-1707. [CrossRef] [PubMed]
 
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