Diagnosis of anesthetic-induced upper airway obstruction in children using respiratory inductance plethysmography.
OBJECTIVE
Upper airway obstruction is the most rapid and clinically relevant cause of hypoxia during sedation and anesthesia. This study was designed to determine if respiratory inductance plethysmography (RIP) could quantify the degree of upper airway obstruction caused by induction of general anesthesia.


METHODS
RIP tracings were obtained during induction of general anesthesia in healthy children. Three sets of measurements were obtained during: (1) a 3 minute control period without anesthetics, (2) 3 minutes of 50% nitrous oxide, and (3) halothane administration to complete the induction of general anesthesia. Clinical impression of upper airway obstruction (none, partial, or complete) was correlated with two separate RIP analysis techniques.


RESULTS
Three hundred ninety-five breathing epochs from 20 children (ages 3-10 years) were analyzed by both phase shift and phase inversion techniques. Although both techniques had good general correlation with severity of airway obstruction, neither was sufficiently reliable for accurate prediction of severity of airway obstruction.


CONCLUSIONS
We investigated two methods for analyzing RIP tracings during varying degrees of upper airway obstruction in anesthetized children. We found that neither technique was sufficiently accurate for predicting the severity of upper airway obstruction and would not be useful as a predictor of upper airway obstruction in the clinical or research settings.
Litman
Ronald S
RS
Department of Anesthesiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. Litmanr@email.chop.edu
Kottra
Jennifer A
JA
Gallagher
Paul R
PR
Ward
Denham S
DS
D000402:Airway Obstruction / Q000175:diagnosis* / Q000209:etiology; D000768:Anesthesia, General / Q000009:adverse effects*; D018685:Anesthetics, Inhalation; D002648:Child; D002675:Child, Preschool; D005260:Female; D006221:Halothane; D006801:Humans; D008297:Male; D009609:Nitrous Oxide; D010991:Plethysmography / Q000379:methods; D012815:Signal Processing, Computer-Assisted; D013909:Thorax
D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide; D006221:Halothane