VARGAS M, Esquinas A

VARGAS, MARIA

Archivio della ricerca - Università degli studi di Napoli Federico II

DownloadUnheated or NoHumidiﬁcation Bubble forLong-Term Nasal Low-FlowOxygenA Matter of Nasal Mucosa Responseor Disease ProgressionTo the Editor:We have read with great interest the paper by Franchiniet al1 published in CHEST (August 2016), whichreported on a randomized clinical trial comparing theeffects of dry nasal low-ﬂow oxygen (NLFO) and coldbubble humidiﬁed NLFO on nasal mucociliary clearance(MCC), mucus properties, inﬂammation, and symptomsin subjects with chronic hypoxemia requiring long-termdomiciliary oxygen therapy. A few issues come to mind.First, this study showed that cold bubble humidiﬁedNLFO and dry nasal NLFO had similar effects on MCC,mucus hydration, and pulmonary function.Furthermore, NLFO therapy signiﬁcantly improved thesymptoms of coughing and sleep disturbance withoutstatistical differences between the humidiﬁed and drynasal NLFO groups.Second, in this study, neither of the NLFO treatmentsreached the recommended levels of temperature andhumidity (100% relative humidity and 44 mg/L absolutehumidity [AH]).1 Humidiﬁed NLFO obtained higher AH(21 mg/L) compared with dry nasal NLFO (9 mg/L). Theoptimal conditions of AH and relative humidity help tokeep stable the rheological characteristics and volume ofairway secretions, increase the mucociliary clearance, andprevent the inﬂammatory reactions to thermal injury orﬂuid imbalance. The heated humidiﬁcation during NLFOprovides a better temperature and humidity of inspiredgas, preserving the MCC and pulmonary function. Theauthors declared that the evaluation of the clinical impactof heated humidiﬁcation during NLFO was beyond thescope of this study. This choice may be questionable. Wethink that the inclusion of a third group with heatedhumidiﬁed NLFO would have added more value to thisstudy, since it has considerable effects on the consideredend points.Third, this study included patients with chronicobstructive disease. Mucus hypersecretion andchronic productive cough are particular features ofchronic bronchitis. The primary mechanismsresponsible for excessive mucus production in COPD750 Correspondenceed From: http://journal.publications.chestnet.org/ by a Hinari User  on are the overproduction and hypersecretion by gobletcells, inﬂammatory cell activation, and mucin genetranscription.2 Furthermore, the progression of COPDis also associated with pathologic deterioration ofmucociliary clearance and lung function.3According to the Global Initiative on Obstructive LungDisease (GOLD) classiﬁcation of severity of airﬂowlimitation in COPD, at the beginning of the study theincluded patients were in GOLD 3 but they worsenedafter 24 months reaching GOLD 4.4 Since the chronicrespiratory disease exacerbated over time in this study, itis hard to say whether the worsening of nasal mucosafunctional status is due to the chronic illness progressionor to the use of NLFO. We think that further prospectivestudies should investigate this topic.Maria Vargas, MDNaples, ItalyAntonio M. Esquinas, MD, PhD, FCCPMurcia, SpainAFFILIATIONS: From University of Naples “Federico II” (Dr Vargas)and Hospital Morales Meseguer (Dr Esquinas).FINANCIAL/NONFINANCIAL DISCLOSURES: None declared.CORRESPONDENCE TO: Maria Vargas, MD, Department ofNeurosciences, Reproductive and Odonthostomatological Sciences,University of Naples “Federico II”, Naples, Italy; e-mail: vargas.maria82@gmail.comCopyright  2016 American College of Chest Physicians. Publishedby Elsevier Inc. All rights reserved.DOI: http://dx.doi.org/10.1016/j.chest.2016.05.039References1. Franchini ML, Athanazio R, Amato-Lourenço LF, et al. Oxygen withcold bubble humidiﬁcation is no better than dry oxygen in preventingmucus dehydration, decreased mucociliary clearance, and decline inpulmonary function. Chest. 2016;150(2):407-414.2. Vestbo J, Hurd SS, Agusti A, et al. Global strategy for the diagnosis,management, and prevention of chronic obstructive pulmonarydisease. Am J Respir Crit Care Med. 2013;187:347-365.3. Ramos FL, Krahnke JS, Kim V. Clinical issues of mucus accumulationin COPD. Int J Chron Obstruct Pulmon Dis. 2014;9:139-150.4. Williams R, Rankin N, Smith T, Galler D, Seakins P.Relationship between the humidity and temperature of inspiredgas and the function of the airway mucosa. Crit Care Med.1996;24:1920-1929.ResponseTo the Editor:We thank Drs Vargas and Esquinas for their interestin our manuscript.1 We fully agree that a third studyarm including heated humidiﬁcation would haveprovided a worthy comparison. Indeed, we havepreviously published that in infants receiving chronic[ 1 5 0 # 3 CHES T S E P T EM B E R 2 0 1 6 ]09/12/2016

UNHEATED OR NO HUMIDIFICATION BUBBLE FOR LONG-TERM NASAL FLOW OXYGEN. A MATTER OF NASAL MUCOSA RESPONSE OR DISEASE PROGRESSION

https://www.iris.unina.it/retrieve/handle/11588/678306/126249/Chest.%c2%a02016%20Sep%3b150%283%29_750.pdf

UNHEATED OR NO HUMIDIFICATION BUBBLE FOR LONG-TERM NASAL FLOW OXYGEN. A MATTER OF NASAL MUCOSA RESPONSE OR DISEASE PROGRESSION

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Archivio della ricerca - Università degli studi di Napoli Federico II