Effects of Nasal Prongs on Nasal Airflow Resistance

doi:10.1378/chest.118.2.366

Chest

Volume 118, Issue 2, August 2000, Pages 366-371

https://doi.org/10.1378/chest.118.2.366 Get rights and content

Study objectives

The aim of this study was to investigate whether nasal prongs, which have been proposed to assess nasal flow during sleep, affect nasal airflow resistance (NR).

Design

NR was estimated by posterior rhinomanometry at a 0.5 L/s flow, under eight conditions: in the basal state, and with seven different nasal prongs.

Participants

The study was performed in 17 healthy supine subjects, 8 of whom had basal NR values within the normal range (≤ 2 cm H₂O·L⁻¹·s, group 1), and 9 had increased basal NR values (> 2.5 cm H₂O·L⁻¹·s, group 2), because of nare narrowness and/or deviated nasal septum.

Measurements and results

NR increased significantly while breathing with nasal prongs (p < 0.0001 in both groups). The changes in NR (ΔNR) induced by the different nasal prongs were characterized by large intersubject and intrasubject variability, with a maximum ΔNR of 24.2 cm H₂O·L⁻¹·s. Significant differences were found between the ΔNR induced by the different nasal prongs (p < 0.001 in group 1, and p < 0.0003 in group 2), and for six of them, ΔNR was significantly higher in group 1 than in group 2 (p < 0.02).

Conclusions

This study demonstrates that nasal prongs can markedly increase NR in subjects presenting with nare narrowness and/or deviated nasal septum. Further investigations that would include nocturnal polysomnography are still required to evaluate the possible influence of nasal prongs on the diagnosis of obstructive sleep apnea syndrome and its severity.

Section snippets

Subjects

The study was performed in a group of 17 asymptomatic healthy volunteers (5 men and 12 women), aged 22 to 54 years, with no upper or lower respiratory complaints. Eight subjects had normal nasal morphology and basal NR values within the normal range, ie,≤ 2 cm H₂O·L⁻¹·s (group 1); nine subjects had nasal anatomic abnormalities, such as nare narrowness and/or deviated nasal septum, and NR basal values ≥ 2.5 cm H₂O·L⁻¹·s (group 2).

NR Measurement

NR was measured by posterior rhinomanometry. The subjects breathed

Results

In the initial basal state, NR ranged from 1.2 to 1.8 cm H₂O·L⁻¹·s in group 1, with a mean value of 2.4 ± 0.1 cm H₂O·L⁻¹·s, and from 2.5 to 4.5 cm H₂O·L⁻¹·s in group 2, with a mean value of 3.0 ± 0.2 cm H₂O·L⁻¹·s. No significant difference was observed between the NR basal values obtained before and after each measurement with nasal prongs (p > 0.6).

When breathing with nasal prongs, the Ptn– $\dot{V}$ relationship became more curved (Fig 2), and NR significantly increased in both groups (p <

Discussion

Nasal prongs were demonstrated to be convenient for ventilation monitoring during sleep, even if their sensitivity and specificity for assessing the severity of flow limitation are lower than those found using a pneumotachograph.⁹ As easily usable as thermistors, they provide a semiquantitative evaluation of airflow, and thereby are more sensitive for the detection of sleep respiratory events, including inspiratory flow limitation.⁴⁵ However, the main requirement for nasal prongs to be

References (15)

AM Lorino et al.
Effects of different mechanical treatments on nasal resistance assessed by rhinometry
Chest
(1998)
R Condos et al.
Flow limitation as a noninvasive assessment of residual upper-airway resistance during continuous positive airway pressure therapy of obstructive sleep apnea
Am J Respir Crit Care Med
(1994)
JM Montserrat et al.
Time-course of stepwise CPAP titration
Am J Respir Crit Care Med
(1995)
Sleep-related
breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research
Sleep
(1999)
RG Norman et al.
Detection of respiratory events during NPSG: nasal cannula/pressure sensor versus thermistor
Sleep
(1997)
JJ Hosselet et al.
Detection of flow limitation with a nasal cannula/pressure transducer system
Am J Respir Crit Care Med
(1998)
M Gugger et al.
Accuracy of an intelligent CPAP machine with in-built diagnostic abilities in detecting apnoeas: a comparison with polysomnography
Thorax
(1995)

There are more references available in the full text version of this article.

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Prolonged partial obstruction during sleep is a NREM phenomenon
2018, Respiratory Physiology and Neurobiology
Citation Excerpt :
Evaluating flow limitation measured by nasal pressure transducer signal, which is considered as a marker of partial collapse in upper airways, is a more common method to quantify partial obstruction than the Emfit signal that is used in our study (Hernandez et al., 2001; Bao and Guilleminault, 2004; Johnson et al., 2005; Sabil et al., 2004; Condos et al., 1994). Measuring flow limitation is, however, problematic since nasal prongs may even increase upper airway resistance (Lorino et al., 2000), and obstruction may prevail without flow limitation (Tenhunen et al., 2011). Moreover, flow limitation is not always caused by upper airway obstruction (Condos et al., 1994), but instead may indicate a decrease in breathing effort (Arora et al., 2015).
Prolonged partial obstruction (PPO) is a common finding in sleep studies. Although not verified, it seems to emerge in deep sleep. We study the effect of PPO on sleep architecture or sleep electroencephalography (EEG) frequency.
Fifteen OSA patients, 15 PPO + OSA patients and 15 healthy subjects underwent a polysomnography. PPO was detected from Emfit mattress signal. Visual sleep parameters and median NREM sleep frequency of the EEG channels were evaluated.
The amount of deep sleep (N3) did not differ between the PPO + OSA and control groups (medians 11.8% and 13.8%). PPO + OSA-patients’ N3 consisted mostly of PPO. PPO + OSA patients had lighter sleep than healthy controls in three brain areas (Fp2-A1, C4-A1, O1-A2, p-values < 0.05).
PPO evolved in NREM sleep and especially in N3 indicating that upper airway obstruction does not always ameliorate in deep sleep but changes the type. Even if PPO + OSA-patients had N3, their NREM sleep was lighter in three EEG locations. This might reflect impaired recovery function of sleep.
The relationship between partial upper-airway obstruction and inter-breath transition period during sleep
2017, Respiratory Physiology and Neurobiology
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While this makes the outcomes of our work clinically generalizable and easily comparable to other research (Hosselet et al., 1998; Series and Marc, 1999), it also has some limitations. It is not a true amplitude-calibrated proxy for flow, and it is recognized that nasal prongs themselves may increase upper airway resistance (Lorino et al., 2000). The lack of calibrated flow means that while we can identify within-patient changes in resistance, we do not have absolute measures of resistance that can be compared between patients.
Short pauses or “transition-periods” at the end of expiration and prior to subsequent inspiration are commonly observed during sleep in humans. However, the role of transition periods in regulating ventilation during physiological challenges such as partial airway obstruction (PAO) has not been investigated. Twenty-nine obstructive sleep apnea patients and eight controls underwent overnight polysomnography with an epiglottic catheter. Sustained-PAO segments (increased epiglottic pressure over ≥5 breaths without increased peak inspiratory flow) and unobstructed reference segments were manually scored during apnea-free non-REM sleep. Nasal pressure data was computationally segmented into inspiratory (T_I, shortest period achieving 95% inspiratory volume), expiratory (T_E, shortest period achieving 95% expiratory volume), and inter-breath transition period (T_Trans, period between T_E and subsequent T_I). Compared with reference segments, sustained-PAO segments had a mean relative reduction in T_Trans (−24.7 ± 17.6%, P < 0.001), elevated T_I (11.8 ± 10.5%, P < 0.001), and a small reduction in T_E (−3.9 ± 8.0, P ≤ 0.05). Compensatory increases in inspiratory period during PAO are primarily explained by reduced transition period and not by reduced expiratory period.
Heart rate variability evaluation of Emfit sleep mattress breathing categories in NREM sleep
2015, Clinical Neurophysiology
Heart rate variability (HRV) analysis of obstructive sleep apnea patients reveals an increase in sympathetic activity. Sleep disordered breathing (SDB) can be also assessed with sleep mattress sensors, as the Emfit sensor, by dividing the signal into different breathing categories. In addition to normal breathing (NB) and periodic apneas/hypopneas (POB), the sleep mattress unveils a breathing category consisting of sustained partial obstruction (increased respiratory resistance, IRR). The aim of our study was to evaluate HRV during these three breathing categories in NREM sleep.
53 patients with suspected SDB underwent an overnight polysomnography with an Emfit mattress. The Emfit signal was scored in 3-min epochs according to the established rules. The NB, POB, and IRR epochs were combined to as long NB, POB and IRR periods as possible and HRV was calculated from at least 6-min epochs.
The meanHR did not differ between the breathing categories. HRV parameters revealed an increase in sympathetic activity during POB. The mean LF/HF ratio was highest during POB (3.0) and lowest during IRR (1.3). During NB it was 1.7 (all p-values ⩽ 0.001). Interestingly sympathetic activity decreased and parasympathetic activity increased during IRR as compared to NB (the mean HF power was 1113.8 ms² during IRR and 928.4 ms² during NB).
The HRV findings during POB resembled HRV results of sleep apnea patients but during sustained prolonged partial obstruction a shift towards parasympathetic activity was achieved.
The findings encourage the use of sleep mattresses in SDB diagnostics. In addition the findings suggest that sustained partial obstruction represents its own SDB entity.
Compressed tracheal sound analysis in screening of sleep-disordered breathing
2008, Clinical Neurophysiology
Citation Excerpt :
Common experience is, however, that the nasal pressure transducer can detach during the night. Nasal cannulas can markedly increase the nasal airflow resistance in subjects presented with nare narrowness and/or deviated nasal septum (Lorino et al., 2000). Although subjective nasal obstruction does not necessarily impair the accuracy of nasal pressure monitoring (Thurnheer et al., 2001), it is possible that impaired nasal ventilation prevents adequate measurements of nasal pressure in some subjects (Series and Marc, 1999).
To evaluate the suitability of compressed tracheal sound signal for screening sleep-disordered breathing.
Thirty-three consecutive patients underwent a polysomnography with a tracheal sound analysis. Nineteen patients were healthy except for the sleep complaint, 9 were hypertonic and 3 were hypertonic and had elevated cholesterol. Minimum and maximum values of each consecutive, non-overlapping segment of 15 s of original sound data were extracted. All these compressed tracheal sound traces were divided into plain, thin and thick signal periods. Also pure, 10-min episodes of plain, thin and thick tracheal sound periods were selected and the nasal pressure flow shapes during these pure sound periods were examined.
There was a significant positive correlation between the total nocturnal amount of thick periods and AHI. Apneas and hypopneas were most common during the 10-min episodes of thick sound periods. The proportion of round (normal, non-flattened) inspiratory flow shape was highest during the pure plain periods.
Breathing consisting of apneas and hypopneas can quite reliably be visualised with compressed tracheal sound analysis. The other interesting outcome of the study is that even prolonged flow limitation might be revealed with the method.
Compressed tracheal sound analysis might provide a promising screening method for obstructive apneas and hypopneas.
Sleep, breathing and the nose
2005, Sleep Medicine Reviews
During sleep there is a discrete fall in minute ventilation and an associated increase in upper airway resistance. In normal subjects, the nasal part of the upper airway contributes only little to the elevation of the total resistance, which is mainly the consequence of pharyngeal narrowing. Yet, swelling of the nasal mucosa due to congestion of the submucosal capacitance vessels may significantly affect nasal airflow. In many healthy subjects an alternating pattern of congestion and decongestion of the nasal passages is observed. Some individuals demonstrate congestion of the ipsilateral half of the nasal cavity when lying down on the side. Nasal diseases, including structural anomalies and various forms of rhinitis, tend to increase nasal resistance, which typically impairs breathing via the nasal route in recumbency and during sleep. A role of nasal obstruction in the pathogenesis of sleep-disordered breathing has been implicated by many authors. While it proves difficult to show a relationship between the degree of nasal obstruction and the number of disturbed breathing events, the presence of nasal obstruction will most likely have an impact on the severity of sleep-disordered breathing. Identification of nasal obstruction is important in the diagnostic work-up of patients suffering from snoring and sleep apnea.
Nasal cannula: Importance and limits
2004, Medecine du Sommeil
L’évaluation de la ventilation et donc du débit aérien est un élément clé de l’évaluation des troubles respiratoires nocturnes par des enregistrements polysomnographiques ou polygraphiques ventilatoires. La mesure de la pression nasale par des lunettes nasales connectées à un capteur de pression est maintenant considérée comme un bon outil pour évaluer de façon semi-quantitative le débit nasal et permettre la quantification des apnées, hypopnées et détecter les limitations de débit inspiratoire. Elles sont d’utilisation plus facile et plus confortable que le pneumotachographe. Elles sont plus performantes que les thermistances pour mettre en évidence les apnées et surtout les hypopnées. Elles permettent également d’objectiver les épisodes de limitations du débit inspiratoire reflétant l’augmentation des efforts respiratoires et responsables de micro-éveils. La principale limite de la méthode est la respiration buccale et l’obstruction nasale et donc la détection d’évènements en excès. Ceci justifie l’utilisation d’un capteur complémentaire aux lunettes nasales pour détecter le flux aérien buccal.
Assessment of breathing flow is a key feature for the evaluation of respiratory sleep disturbances during nocturnal polysomnographic or ventilatory recordings. Measurement of nasal pressure using nasal prongs connected to a pressure transducer is now considered as a suitable tool for semi-quantitative assessment of nasal flow, quantification of apnea and hypopnea and detection of inspiratory flow limitation. The use of nasal prongs is easier and more confortable for the patients than a pneumotachograph. Nasal prongs allow a more accurate assessment of apneas and hypopneas than thermistors or thermocouples. They allow the detection of inspiratory flow limitations which indicate increased respiratory efforts and cause sleep disruption. The main limit of the technic is mouth breathing and nasal obstruction. The use of and additional sensor to detect buccal airflow is therefore recommanded.

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Chest

Clinical Investigations: Sleep and BreathingEffects of Nasal Prongs on Nasal Airflow Resistance

Study objectives

Design

Participants

Measurements and results

Conclusions

Section snippets

Subjects

NR Measurement

Results

Discussion

Chest

Flow limitation as a noninvasive assessment of residual upper-airway resistance during continuous positive airway pressure therapy of obstructive sleep apnea

Am J Respir Crit Care Med

Time-course of stepwise CPAP titration

Am J Respir Crit Care Med

breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research

Sleep

Detection of respiratory events during NPSG: nasal cannula/pressure sensor versus thermistor

Sleep

Detection of flow limitation with a nasal cannula/pressure transducer system

Am J Respir Crit Care Med

Accuracy of an intelligent CPAP machine with in-built diagnostic abilities in detecting apnoeas: a comparison with polysomnography

Thorax

Clinical Investigations: Sleep and Breathing
Effects of Nasal Prongs on Nasal Airflow Resistance