Related Experiment Video
Updated: Sep 22, 2026

Evaluation of Respiratory System Mechanics in Mice using the Forced Oscillation Technique
Published on: May 15, 2013
Assessment of Pulmonary Functions in Adenotonsillar Hypertrophy Patients Using a Newer Modality of Forced Oscillation
Vidya Shekar1, Krishnaswamy Kothandapani Shyamala2, Ashwini Shastry1
1Department of ENT, Dr B R Ambedkar Medical College, Bengaluru, India.
Introduction:
Adenotonsillar hypertrophy (ATH) is a common cause of upper airway obstruction in the paediatric population, resulting in sleep disturbances, chronic airway obstruction, and potential cardiopulmonary complications. The Forced Oscillation Technique (FOT) is a sensitive, non-invasive method for assessing pulmonary function and detecting abnormalities of the peripheral airways.
Materials And Methods:
This prospective pre-post cohort study included 35 patients aged 5-20 years with ATH who underwent FOT assessment before and six weeks after adenotonsillectomy. The parameters evaluated included total airway resistance (R5), central airway resistance (R20), peripheral airway resistance (R5-R20), reactance (X5), area of reactance (Ax), and resonant frequency (Fres).
Results:
Significant postoperative improvements were observed in R5 (0.46±0.25 to 0.41±0.25 kPa/L/s; p = 0.001), R20 (0.35±0.19 to 0.30±0.18 kPa/L/s; p = 0.001), X5 (-0.24±0.16 to -0.12±0.13 kPa/L/s; p < 0.001), Ax (2.93±2.30 to 2.08±1.71 kPa/L/s; p < 0.001), and Fres (24.89±6.75 to 22.30±6.00 Hz; p < 0.001). Although R5-R20 improved (0.10±0.10 to 0.09±0.10 kPa/L/s), the change was not statistically significant (p = 0.427). As R5-R20, X5, and Ax reflect peripheral airway function, improvements in these parameters suggest enhanced peripheral airway function following adenotonsillectomy. No significant association was found between pulmonary function and the degree of adenoid or tonsillar hypertrophy.
Conclusion:
FOT effectively detected improvements in pulmonary function following adenotonsillectomy and may be a valuable tool for evaluating respiratory changes in patients with ATH. Larger studies are warranted to better define its clinical utility.
Related Concept Videos
Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
Physical Assessment of the Respiratory Tract II: Palpation
Thoracic Palpation
Thoracic palpation detects tenderness, masses, lesions, respiratory excursions, and vocal fremitus. The nurse assesses...
Physical Assessment of the Respiratory Tract III: Percussion
Percussion in Respiratory Assessment
Percussion evaluates underlying tissue composition with audible and tactile vibrations,...
Physical Assessment of the Respiratory Tract IV: Auscultation
Breath Sounds
Breath sounds are categorized into vesicular, bronchovesicular, and bronchial.
Respiratory System Abnormal Finding II: Palpation and Auscultation
Palpation Findings
During a respiratory assessment, palpation can reveal several vital abnormalities:
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History

