Related Experiment Video
Updated: Oct 10, 2025
Monitoring Lung Function with Electrical Impedance Tomography in the Intensive Care Unit
Published on: September 6, 2024
Evaluation of atelectasis using electrical impedance tomography during procedural deep sedation for MRI in small
Thomas Riva1, Fabio Pascolo2, Markus Huber2
1Department of Anesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Unit for Research & Innovation in Anesthesia, Department of Pediatric Anesthesia, Istituto Giannina Gaslini, Genova, Italy.
Insights
Deep sedation increases poorly ventilated lung units in children during procedures. However, lung ventilation homogeneity fully recovers before discharge from the Post-Anesthesia Care Unit (PACU), with no lasting complications.
Area of Science:
- Pediatric Anesthesiology
- Respiratory Physiology
- Medical Imaging
Background:
- Procedural sedation is common in pediatric day-hospital settings.
- Understanding its effects on lung ventilation is crucial for patient safety.
- Poorly ventilated lung units (silent spaces) can impact gas exchange.
Purpose of the Study:
- To investigate changes in silent spaces during procedural sedation in children.
- To assess lung ventilation homogeneity throughout the sedation and recovery process.
- To determine if ventilation abnormalities persist until discharge.
Main Methods:
- Prospective observational cohort study involving 25 children (1-6 years) undergoing sedation for MRI.
- Deep sedation was induced using propofol with supplemental nasal oxygen.
- Electrical impedance tomography (EIT) was used to measure silent spaces and global inhomogeneity index at five time points.
Main Results:
- The proportion of silent spaces significantly increased during sedation, peaking after the MRI.
- No significant difference was found in silent spaces from before induction to before PACU discharge.
- Global inhomogeneity indices remained stable, and no anesthesia-related complications occurred.
Conclusions:
- Deep sedation temporarily increases poorly ventilated lung units in children.
- Ventilation homogeneity is not significantly affected and resolves by PACU discharge.
- Procedural sedation appears safe regarding lung ventilation in this pediatric cohort.
Study Objective:
To investigate the variation of poorly ventilated lung units (i.e., silent spaces) in children undergoing procedural sedation in a day-hospital setting, until discharge home from the Post-Anesthesia Care Unit (PACU).
Design:
Prospective, single-center, observational cohort trial.
Setting:
This study was conducted at the radiology department and in PACU at Bern University Hospital (Switzerland), a tertiary care hospital.
Patients:
We included 25 children (1-6 years, ASA I-III) scheduled for cerebral magnetic resonance imaging scan, spontaneously breathing under deep sedation. Children planned for tracheal intubation, supraglottic airway insertion, or with contraindication for propofol were excluded.
Intervention:
After intravenous or inhaled induction, deep sedation was performed with 10 mg/kg/h Propofol. All children received nasal oxygen 0.3 ml/kg/min.
Measurements:
The proportion of silent spaces and the global inhomogeneity index were determined at each of five procedural points, using electrical impedance tomography: before induction (T1); before (T2) and after (T3) magnetic resonance imaging; at the end of sedation before transport to the PACU (T4); and before hospital discharge (T5).
Main Results:
The median [interquartile range (IQR)] proportion of silent spaces at the five analysis points were: T1, 5% [2%-14%]; T2, 10% [7%-14%]; T3, 12% [5%-23%]; T4, 12% [7%-24%]; and T5, 3% [2%-11%]. These defined significant changes in silent spaces over the course of sedation (p = 0.009), but no differences in silent spaces from before induction to before discharge from the PACU (T1 vs. T5; p = 0.29). Median [IQR] global inhomogeneity indices were 0.57 [0.55-0.58], 0.56 [0.53-0.59], 0.56 [0.54-0.59], 0.57 [0.54-0.60] and 0.56 [0.54-0.57], respectively (p = 0.93). None of the children reported anesthesia-related complications.
Conclusion:
Deep sedation results in significantly increased poorly ventilated lung units during sedation. However, this does not significantly affect ventilation homogeneity, which was fully resolved at discharge from the PACU.
Trial Registration:
clinicaltrials.gov, identifier NCT04507581.
