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Updated: Apr 15, 2026

Assessment of Respiratory Function in Conscious Mice by Double-chamber Plethysmography
Published on: July 10, 2018
New insights on the pathophysiology of inspiratory flow limitation during sleep
Luciana B M de Godoy1, Luciana O Palombini, Fernanda L Martinho Haddad
1Disciplina de Medicina e Biologia do Sono, Departamento de Psicobiologia, Universidade Federal de Sao Paulo, Rua Napoleao de Barros 925, Sao Paulo, 04024-002, Brazil, lu_bmg@yahoo.com.br.
Introduction:
Inspiratory flow limitation (IFL) is defined as a "flattened shape" of inspiratory airflow contour detected by nasal cannula pressure during sleep and can indicate increased upper airway resistance especially in mild sleep-related breathing disorders (SRBD). The objective of this study was to investigate the association between upper airway abnormalities and IFL in patients with mild SRBD.
Methods:
This study was derived from a general population study consisting of selected individuals with apnea-hypopnea index (AHI) below 5 events/h of sleep, ("no obstructive sleep apnea" group) and individuals with AHI between 5 and 15 events/h ("mild obstructive sleep apnea" group). A total of 754 individuals were divided into four groups: group 1: AHI <5/h and <30 % of total sleep time (TST) with IFL (515 individuals), group 2: AHI <5/h and >30 % of TST with IFL (46 individuals), group 3: AHI: 5-15/h and <30 % of TST with IFL (168 individuals), and group 4: AHI: 5-15/h and >30 % of TST with IFL (25 individuals).
Results:
Individuals with complains of oral breathing demonstrated a risk 2.7-fold larger of being group 4 compared with group 3. Abnormal nasal structure increased the chances of being in group 4 3.2-fold in comparison to group 1. Individuals with voluminous lateral wall demonstrated a risk 4.2-fold larger of being group 4 compared with group 3.
Conclusion:
More than 30 % of TST with IFL detected in sleep studies was associated with nasal and palatal anatomical abnormalities in mild SRBD patients.
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