Copenhagen, Denmark
Onsite/Online

ESTRO 2022

Session Item

Other
Poster (digital)
Interdisciplinary
Quantification of diaphragm motion with ultrasound during non-invasive high frequency ventilation
Kaylee van Duren, The Netherlands
PO-1056

Abstract

Quantification of diaphragm motion with ultrasound during non-invasive high frequency ventilation
Authors:

Kaylee van Duren1, Jeffrey Veldman1, Michael Parkes1, Zdenko van Kesteren1, Markus Stevens2, Joost van Schuppen3, Geertjan van Tienhoven1, Arjan Bel1, Irma van Dijk1

1Amsterdam UMC, Radiation Oncology, Amsterdam, The Netherlands; 2Amsterdam UMC, Anaesthesiology, Amsterdam, The Netherlands; 3Amsterdam UMC, Radiology, Amsterdam, The Netherlands

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Purpose or Objective

Breathing motion causes substantial uncertainties in tumor position during radiotherapy. High frequency ventilation with small tidal volumes reduces the amplitude of breathing motion. The aim of this study was to quantify the motion of the right diaphragm dome in conscious healthy volunteers during non-invasive mechanical ventilation without percussion at various high frequency settings, using ultrasound.

Material and Methods

Seven volunteers were mechanically ventilated with Positive End Expiratory Pressure (PEEP) at 60 breaths per minute (brpm) using a Hamilton-T1 ventilator, and at 60, 150, 250 and 400 brpm using a TwinStream jet-ventilator. During 40 s recordings, 900 consecutive sagittal images of the diaphragm were acquired using the bk3000 ultrasound system (BK Medical Benelux NV/SA, Mechelen, Belgium) with a convex ultrasound probe at 3.5 MHz and a temporal resolution of 23 frames per second. The same trained operator made all measurements. Measurements were undertaken in two separate sessions. The order of ventilation frequency settings for the TwinStream was randomized. The images from six volunteers of both measurement sessions and at all ventilation frequency settings were adequate and further analyzed semi-automatically in MATLAB (n=12). Excursions were determined based on a time motion image along the direction of movement near the anterior layer of the coronary ligament (Fig.1). From each time motion image, the diaphragm was segmented by thresh holding and the mean diaphragm excursion (peak – trough) for all inflations determined and analyzed with a Wilcoxon signed-rank test (Bonferroni adjusted α=0.05/4).

Results

The mean diaphragm excursion (8mm) at 60 brpm using the TwinStream ventilator showed a significantly larger median excursion (p=0.002) than when using any other ventilation frequency setting (Fig. 2). The smallest diaphragm excursions, with a mean of 1 mm, were found using the TwinStream ventilator at 250 and 400 brpm. At all ventilation frequencies except using the TwinStream ventilator at 60 brpm the mean inter-session variability was <1 mm.








Conclusion

Motion of the right diaphragm dome during non-invasive high frequency ventilation was successfully quantified using ultrasound. High frequency ventilation without percussion is a promising breathing regularization strategy to reduce the diaphragm motion, especially using the TwinStream ventilator at 250 or 400 brpm.