Petruson B,

Increased nasal breathing decreases snoring and improves oxygen saturation during sleep apnoea,

Rhinology. 1994 Jun; 32(2): p.87-89.

ENT Department, Sahlgren's Hospital, University of Göteborg, Sweden.

For many years ENT-specialists have performed surgery to create a good air passage in patients with different kinds of nasal deformities. When having a blocked nose one realizes the importance of being able to breathe through the nose. By moving the nasal wings aside with the fingers, or the medical device Nozovent, most people experience that it is easier to breathe through the nose than ever before, which can also be shown with rhinomanometry. When it is easier to inhale there is less energy in the air passing the palate which means less risk for vibrations creating snoring sounds. In different studies it has been possible to show that snoring can be decreased or prevented when the nasal dilator Nozovent is used. It has also been shown to result in a decrease of the sleep apnoea index and improvement of arterial oxygen saturation during sleep apnoea.

Bushell MK, Baldock PJ, Antic R, Thornton AT, McEvoy RD,

Obligatory nasal breathing: effects on snoring and sleep apnoea,

Med J Aust. 1991 Jul 15; 155(2): p.83-85.

Department of Thoracic Medicine, Royal Adelaide Hospital, North Terrace, SA, USA.

OBJECTIVE: To test the effects on snoring and sleep disordered breathing of a dental prosthesis (Snore-No-More) which is designed to decrease snoring by preventing mouth breathing during sleep. DESIGN: A crossover controlled trial. Each subject was studied on two nights a week apart. There was a control (no treatment) night and an experimental (treatment) night. The order of control and experimental nights was randomised. SETTING: The Royal Adelaide Hospital Sleep Laboratory. PARTICIPANTS: Fourteen male volunteers (age range, 36-59 years) were studied. All had a history of chronic snoring but denied other symptoms of obstructive sleep apnoea syndrome. INTERVENTIONS: On experimental nights subjects wore the dental prosthesis for the whole study period. On control nights no device was worn. MAIN OUTCOME MEASURES: Studies were conducted overnight during the subject's normal sleep period. The following measurements were made: (i) frequency and loudness of snores; (ii) frequency of disordered breathing events (apnoeas and hypopnoeas); (iii) mean and minimum arterial oxygen saturation while asleep; and (iv) sleep stages. RESULTS: The dental prosthesis did not change the mean frequency or mean intensity of snores. The number of sleep disordered breathing events per hour of sleep decreased by approximately one-third on experimental nights (mean +/- SEM events/h: control, 24.7 +/- 5.3; experimental, 16.1 +/- 3.3, P less than 0.05). Neither sleep architecture nor arterial oxygen saturation differed between control and experimental nights. CONCLUSION: Snores using the dental prosthesis Snore-No-More to produce obligatory nasal breathing are unlikely to experience clinical benefit.

Gleeson K, Zwillich CW, Braier K, White DP,

Breathing route during sleep,

Am Rev Respir Dis 1986 Jul; 134(1): p.115-120.

Nasal obstruction has been associated with apneic episodes during sleep. However, the normal distribution of nasal and oral air flow while asleep has not been investigated. To determine the normal route of ventilation during sleep, we studied 7 healthy men and 7 healthy women using a sealed face mask that mechanically separated nasal and oral air flow. Standard sleep staging techniques were employed. The subjects slept 297 +/- 29 (SEM) min, with a mean of 197 +/- 15 min of ventilation recorded. Ventilation was decreased during sleep as has been previously demonstrated. However, during sleep, we found that men breathed a greater percentage of total ventilation through the mouth (29.0 +/- 8.2%) than did women (5.0 +/- 1.0%, p less than 0.02). The same trend applied during wakefulness but did not reach significance (p = 0.06). Although none was symptomatic, 4 subjects, all men, had more than 3 apneas per hour. These 4 men had a greater percentage of mouth ventilation (37.3 +/- 19.0%) than did the other 10 subjects with few or no apneas (8.1 +/- 2.7%, p less than 0.02). It was also noted that increasing age in men was associated with an increasing percentage of mouth ventilation (r = 0.83 p less than 0.03) but this relationship was not observed in women. We conclude that mouth breathing may be associated with apneas during sleep and that breathing through the mouth occurs commonly in men, particularly in those who are older. This suggests that nasal breathing may be important in the maintenance of ventilatory rhythmicity during sleep.

Goffart Y,

[Physiopathology of mouth breathing. Snoring and apnea][Article in French]

Acta Otorhinolaryngol Belg. 1993; 47(2): p.157-166.

Centre Hospitalier de La Citadelle, Liège, Belgique.

Oral breathing causes changes in pulmonary mechanics as well as in the pressure of arterial blood gases. In response to increased nasal obstruction oro-nasal breathing occurs. The level of oro-nasal partitioning maintains an adequate level of respiratory resistance. Sleep disordered breathing, although not only related to oral breathing, is a common disorder. When upper airway resistance is increased limitation of flow occurs. Snoring indicates a mild degree of reduced airflow. Sleep apnea occurs when upstream pressure falls below a critical pressure (Pcrit). The mechanisms are reviewed.

Bartley J,

Nasal congestion and hyperventilation syndrome,

Am J Rhinol. 2005 Nov-Dec; 19(6): p.607-611.

Waitemata District Health Board, Auckland, New Zealand.

BACKGROUND: This article evaluates the prevalence of hyperventilation syndrome (HVS) in patients who continue to complain of ongoing nasal congestion, despite an apparently adequate surgical result and appropriate medical management. METHODS: Prospective case series of 14 patients from June 2002 to October 2003 was performed. Patients, who presented complaining of nasal congestion after previous nasal surgery and who appeared to have an adequate nasal airway with no evidence of nasal valve collapse, were evaluated for HVS. When appropriate, nasal steroids and oral antihistamines also had been tested without success. Three patients had end-tidal P(CO2) levels measured and five patients underwent breathing reeducation. RESULTS: All patients had an elevated respiratory rate (>18 breaths/minute) with an upper thoracic breathing pattern. Twelve of the 14 patients complaining of nasal obstruction had an elevated Nijmegen score indicative of HVS. An average number of 2.5 procedures had been performed on each patient. End-tidal P(CO2) levels were < or = 35 mmHg in the three patients who had expired P(CO2) levels measured. Breathing retraining was successful in correcting the nasal congestion in two of five patients. CONCLUSION: HVS should be included in the differential diagnosis of patients presenting with nasal congestion, particularly after failed nasal surgery. One possible explanation is increased nasal resistance secondary to low arterial P(CO2) levels. Another possible explanation is reduced alae nasae muscle activity secondary to the reduced activity of serotonin-containing raphe neurons. Additional surgery may not necessarily be the answer in HVS patients complaining of nasal congestion.

Backon J,

Nasal breathing as a treatment for hyperventilation: relevance of hemispheric activation,

Br J Clin Pract. 1989 Apr;43(4): p.161-162.

ECKERT-MOBIUS A,

[The importance of normal nasal breathing for the physical and mental development of man and for diseases of the respiratory tract],

Munch Med Wochenschr. 1957 Sep 27; 99(39): p.1405-1408 (in German).