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Volume 10 No. 09
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Accepted Papers





Case Reports

Upper Airway Obstruction during Noninvasive Ventilation Induced by the Use of an Oronasal Mask

Bart Vrijsen, P.T., M.Sc.; Bertien Buyse, M.D., Ph.D.; Catharina Belge, M.D., Ph.D.; Dries Testelmans, M.D., Ph.D.
Leuven University Centre for Sleep and wake Disorders, CPAP and Home Mechanical Ventilation, University Hospital Leuven, Leuven, Belgium

ABSTRACT

In patients with neuromuscular disorders, no randomized studies have been performed whether nasal or oronasal masks should be preferred. Oronasal masks are often used in acute respiratory failure, while nasal masks are preferred in patients with chronic respiratory failure. However, the use of nasal masks can result in mouth leaks with implications on sleep quality. To reduce these leaks, oronasal masks have been applied during home noninvasive ventilation (NIV). Until now, upper airway obstruction during NIV has been thought to be induced by nasal obstruction, pharyngeal collapse, and/or glottis closure. We report a case indicating another cause of upper airway obstruction: use of an oronasal mask can induce obstructive events in the upper airways, possibly resulting in sleep fragmentation and decreased efficiency of NIV.

Citation:

Vrijsen B, Buyse B, Belge C, Testelmans D. Upper airway obstruction during noninvasive ventilation induced by the use of an oronasal mask. J Clin Sleep Med 2014;10(9):1033-1035.


In patients with neuromuscular disorders, no randomized studies have been performed whether nasal or oronasal masks should be preferred. Oronasal masks are often used in acute respiratory failure, while nasal masks are preferred in patients with chronic respiratory failure.1 However, the use of nasal masks can result in mouth leaks with implications on sleep quality.2 To reduce these leaks, oronasal masks have been applied during home noninvasive ventilation (NIV).3 Until now, upper airway obstruction during NIV has been thought to be induced by nasal obstruction, pharyngeal collapse, and/ or glottis closure.4 We report a case indicating another cause of upper airway obstruction: use of an oronasal mask can induce obstructive events in the upper airways, possibly resulting in sleep fragmentation and decreased efficiency of NIV.

REPORT OF CASE

A 52-year-old Caucasian male with amyotrophic lateral sclerosis (ALS) suffering from progressive respiratory failure was transferred to our hospital in order to start NIV. ALS was diagnosed 17 months before. No bulbar involvement had been seen prior to this admission. During outpatient daycare, NIV had been suggested, but until this hospital admission, the patient had declined intervention with NIV.

On admission to the intermediate intensive care unit (iICU), the patient showed tachypnea. Blood gas analysis showed pH: 7.42, PaCO2: 67.9 mmHg, HCO3-: 38.7 mmol/L, and PaO2: 84.9 mmHg. The patient indicated complaints of orthopnea and decreased cough strength during the previous week. Blood analysis and chest radiography showed no signs of respiratory infection. At iICU, nocturnal bilevel positive airway pressure with an oronasal mask was started, with inspiratory positive airway pressure (IPAP) of 14 cmH2O and expiratory airway pressure (EPAP) of 4 cmH2O (BiPAP Vision; Respironics, Philips; Murrysville, PA, USA) to stabilize the patient.

After 3 nights in the iICU, patient arrived at the Leuven University Centre for Sleep and wake disorders (LUCS). Diurnal transcutaneous carbon dioxide5 and oxygen saturation measured, respectively, 60 mmHg and 90% to 94%. Nocturnal NIV was continued with a Trilogy 100 ventilator (Respironics, Philips; Murrysville, PA, USA). Ventilator settings of the first night are shown in Table 1. The patient used an oronasal mask, as mouth closure was difficult and the patient was already accustomed to the oronasal mask at the iICU. During the first night at the LUCS, NIV was used for 310 minutes and was interrupted during one episode of 143 minutes. Polysomnography (according to the guidelines of the American Academy of Sleep Medicine) demonstrated an apnea-hypopnea index (AHI) of 33.7/h total sleep and 46.9/h REM sleep. The arousal/awake index was 26.4/h sleep. During analysis of the synchronized digital video recording, different episodes of backward movement of the tongue were visible during inspiration, resulting in obstruction of the upper airways (Video 1). Polysomnography showed a decrease of thoracic and abdominal movement. Consequently, oxygen saturation decreased, each time resulting in an arousal or awakening (Figure 1). During the second night at the LUCS, a nasal mask (with a chin strap to restrain mouth leaks) was applied. Significant reduction in sleep fragmentation and significant improvement of AHI was observed. Although IPAP was reduced (with 4 cmH2O in comparison with the settings of the previous night), an improvement of oxygen saturation and hypercapnia occurred (Table 1). Minimal frequency and inspiratory time were adjusted to increase the minute ventilation with lower IPAP.

Settings of Trilogy 100, sleep architecture, oxygen saturation, and transcutaneous CO2.

jcsm.10.9.1033.t01.jpg

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Table 1

Settings of Trilogy 100, sleep architecture, oxygen saturation, and transcutaneous CO2.

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Polysomnography measurement during 10 minutes of the pressure (PCPAP), the thoracic (VTH) and abdominal (VAB) belts and the oxygen saturation (SaO2). Several oxygen desaturations followed by an arousal (arsl) or awakening (W) are present after obstruction due to backward movement of the tongue. Polysomnography has been measured during different sleep stages: REM sleep (R), stage 1 sleep (N1), and stage 2 sleep (N2). The small figure shows the electroencephalogram measurement (30 sec) during an arousal.

jcsm.10.9.1033a.jpg

jcsm.10.9.1033a.jpg
Figure 1

Polysomnography measurement during 10 minutes of the pressure (PCPAP), the thoracic (VTH) and abdominal (VAB) belts and the oxygen saturation (SaO2). Several oxygen desaturations followed by an arousal (arsl) or awakening (W) are present after obstruction due to backward movement of the tongue. Polysomnography has been measured during different sleep...

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DISCUSSION

Oronasal masks can be used when sleep architecture during nasal NIV is disrupted by leaks. However, this case report in an ALS patient suggests that oronasal masks should be used with caution. Because air is blown into the mouth, a backward movement of the tongue was induced. This could cause obstructive events and lead to decreased oxygen saturation, a disrupted sleep architecture, and persistent hypercapnia. These obstructive events could not be attributed to upper airway instability as these events were not present during treatment with nasal NIV with even lower pressures. Also the possibility of glottic closure due to relative hyperventilation could be eliminated,6 as the transcutaneous carbon dioxide during the night with nasal mask is even more decreased and clinically significant less obstructive events are observed.

If backward movement of the tongue is observed, few solutions can be proposed. During nasal NIV, a chin strap could be applied, although this does not always resolve the problem of mouth leaks.7 If mouth leaks persist, and frequent arousals or awakenings are observed, decreasing IPAP should be considered to ensure sleep quality. Decreasing IPAP during nasal NIV can possibly decrease the risk of mouth leaks, while decrease of IPAP during oronasal application could decrease the possibility of backward movement of the tongue.

As result of progressive neuromuscular weakness, airway obstruction, caused by backward movement of the tongue, could begin even in successful NIV users. Therefore, careful clinical questioning for symptoms such as interrupted sleep is of major importance. In case of uncertainty, nocturnal oximetry and/or poly(somno)graphy could give additional information.

Further research on the effects of different interfaces on the efficacy of positive airway pressure therapy is necessary in patients with neuromuscular disorders and also in large numbers of patients with obstructive sleep apnea.

DISCLOSURE STATEMENT

This was not an industry supported study. The authors have indicated no financial conflicts of interest. The ethical committee of University Hospitals Leuven has given approval to use patient data obtained at the LUCS of the University Hospitals Leuven. Approval number: B322201213466.

REFERENCES

1 

Schönhofer B, Sortor-Leger S, authors. Equipment needs for noninvasive mechanical ventilation. Eur Respir J. 2002;20:1029–36. [PubMed]

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Teschler H, Stampa J, Ragette R, Konietzko N, Berthon-Jones M, authors. Effect of mouth leak on effectiveness of nasal bilevel ventilatory assistance and sleep architecture. Eur Respir J. 1999;14:1251–7. [PubMed]

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Hess DR, author. Noninvasive ventilation in neuromuscular disease: equipment and application. Respir Care. 2006;51:896–911. [PubMed]

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Gonzalez-Bermejo J, Perrin C, Jannsens JP, et al., authors. Proposal for a systematic analysis of polygraphy or polysomnography for identifying and scoring abnormal events occurring during non-invasive ventilation. Thorax. 2012;67:546–52. [PubMed]

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Hazenberg A, Zijlstra J, Kersjens H, Wijkstra P, authors. Validation of a transcutaneous CO2 monitor in adult patients with chronic respiratory failure. Respiration. 2011;81:242–6. [PubMed]

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Jounieaux V, Aubert G, Dury M, Delguste P, Rodenstein DO, authors. Effects of nasal positive-pressure hyperventilation on the glottis in normal sleeping subjects. J Appl Physiol. 1995;79:186–93. [PubMed]

7 

Gonzalez J, Sharshar T, Hart N, Chadda K, Raphaël J, Lofaso F, authors. Air leaks during mechanical ventilation as a cause of persistent hypercapnia in neuromuscular disorders. Intensive Care Med. 2003;29:596–602. [PubMed]