PMID- 2718973
OWN - NLM
STAT- MEDLINE
DCOM- 19890613
LR  - 20190903
IS  - 0889-5406 (Print)
IS  - 0889-5406 (Linking)
VI  - 95
IP  - 5
DP  - 1989 May
TI  - Partitioning of ventilation between nose and mouth: the role of nasal resistance.
PG  - 432-8
AB  - We have examined the relationship between nasal resistance (Rna) and the 
      distribution of ventilation between the nose and mouth in 10 normal breathing 
      children and 15 children who met clinical criteria of mouth breathing. We studied 
      Rna by posterior rhinometry. We used a face mask divided into separate oral and 
      nasal chambers to measure oral and nasal components of ventilation. Each chamber 
      of the mask was connected to a separate pneumotachograph. We measured oral and 
      nasal tidal volumes (VTna) by integration of the oral and nasal flow, and 
      calculated the total tidal volume (VTtot) by summing the oral and nasal 
      components. The nasal fraction of ventilation (F-VTna) was calculated by dividing 
      VTna by VTtot. We found a weak inverse correlation between Rna and F-VTna, but 
      eight of 25 children did not breathe as one might predict on the basis of Rna, 
      and eight of 15 children who appeared to be mouth breathers actually breathed 
      through the nose. We administered a vasoconstricting nasal spray and a placebo 
      nasal spray to the children and, although Rna changed significantly, we observed 
      no change in the distribution of flow between the nose and mouth. In summary we 
      found that clinical criteria of mouth breathing do not accurately identify 
      children who actually breathe mainly through the mouth. Moreover Rna is only a 
      weak predictor of the pattern of breathing; hence other factors may be important 
      determinants of the distribution of flow between the nose and mouth.(ABSTRACT 
      TRUNCATED AT 250 WORDS)
FAU - Leiter, J C
AU  - Leiter JC
AD  - Department of Physiology, Dartmouth Medical School, Hanover, N.H.
FAU - Baker, G L
AU  - Baker GL
LA  - eng
GR  - HL-01998-01/HL/NHLBI NIH HHS/United States
PT  - Clinical Trial
PT  - Controlled Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Orthod Dentofacial Orthop
JT  - American journal of orthodontics and dentofacial orthopedics : official 
      publication of the American Association of Orthodontists, its constituent 
      societies, and the American Board of Orthodontics
JID - 8610224
SB  - IM
MH  - *Airway Resistance
MH  - Child
MH  - Child, Preschool
MH  - Female
MH  - Humans
MH  - Male
MH  - Maxillofacial Development
MH  - Mouth Breathing/*etiology
MH  - Nose/*physiopathology
MH  - Random Allocation
MH  - Reproducibility of Results
MH  - *Respiration
EDAT- 1989/05/01 00:00
MHDA- 1989/05/01 00:01
CRDT- 1989/05/01 00:00
PHST- 1989/05/01 00:00 [pubmed]
PHST- 1989/05/01 00:01 [medline]
PHST- 1989/05/01 00:00 [entrez]
AID - 0889-5406(89)90305-3 [pii]
AID - 10.1016/0889-5406(89)90305-3 [doi]
PST - ppublish
SO  - Am J Orthod Dentofacial Orthop. 1989 May;95(5):432-8. doi: 
      10.1016/0889-5406(89)90305-3.