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Thoracoabdominal asynchrony in acute upper airway obstruction in small children
Y Sivan1, T W Deakers, C J Newth
1Division of Pediatric Intensive Care, Children's Hospital of Los Angeles, University of Southern California School of Medicine 90027.
Insights
Objective assessment of acute upper airway obstruction (UAO) in children is now possible. Researchers used respiratory inductance plethysmography (RIP) to measure chest wall asynchrony, finding it a reliable indicator of UAO severity and treatment response.
Area of Science:
- Pediatric Pulmonology
- Biomedical Engineering
- Respiratory Physiology
Background:
- Assessing acute upper airway obstruction (UAO) severity and treatment response in young children typically relies on subjective clinical observations.
- Objective, quantifiable methods are needed to improve diagnostic accuracy and therapeutic monitoring in pediatric UAO.
Purpose of the Study:
- To objectively quantitate rib cage (RC) to abdominal (AB) asynchrony using the phase angle from respiratory inductance plethysmography (RIP) signals in children with acute UAO.
- To evaluate the efficacy of the phase angle measurement in assessing UAO severity and response to inhalation therapy.
Main Methods:
- Respiratory inductance plethysmography (RIP) was used to record RC and AB movements in 17 children with acute UAO and 30 healthy controls.
- The phase angle between RC and AB signals was calculated to quantify chest wall asynchrony.
- Phase angles were measured before and after inhalation treatment with racemic epinephrine.
Main Results:
- Children with acute UAO exhibited significantly higher phase angles (mean = 83.6°) compared to controls (mean = 11.5°), indicating increased RC-AB asynchrony.
- Following racemic epinephrine treatment, the mean phase angle in the UAO group significantly decreased (mean = 38.3°).
- The phase angle showed a strong correlation with the clinical severity of stridor, with changes in phase angle agreeing with clinical improvement in 90% of cases.
Conclusions:
- Phase angle measurement from a noncalibrated RIP provides an objective method to quantitate RC-AB asynchrony in infants and small children with acute UAO.
- This objective measurement is suitable for clinical use and can effectively assess the response to therapy for UAO.
- The phase angle serves as a valuable tool for objective assessment of UAO severity and therapeutic efficacy in pediatric patients.
Abstract:
The assessment of the severity and response to therapy of acute upper airway obstruction (UAO) in small children relies on subjective parameters. Using a noncalibrated respiratory inductance plethysmograph (RIP), we quantitated the rib cage (RC) to abdominal (AB) asynchrony and the lag phase in chest wall expansion by the phase angle from the RC versus AB signal curve. Phase angles were obtained in 17 children aged 1 to 50 months with acute UAO and 30 normal control subjects. The phase angle in UAO (16 to 165 degrees; mean = 83.6 degrees) was significantly higher than in control subjects (3 to 25 degrees; mean = 11.5 degrees), p less than 0.001. Following 29 episodes of inhalation treatment with 0.03 ml/kg of racemic epinephrine, the phase angle in the UAO group decreased to 7 to 160 degrees (mean = 38.3; p = 0.001) as the shape of the RC versus AB loop became narrower. In response to the treatment, the clinical severity of UAO decreased and the tidal breathing flow-volume loop improved. A high association was observed between the phase angle and the degree of stridor (p less than 0.005 Fisher's exact test), and in 90% (26 of 29) the changes in the phase angle and in the degree of stridor were in agreement. We conclude that the RC-AB asynchrony in acute UAO can be objectively quantitated by phase-angle measurement from a noncalibrated RIP and is thus suitable for use in infants and small children. The phase angle may be used to assess objectively the response of UAO to therapy.