Rapid non-invasive mechanical ventilation appears superior to non-invasive high-frequency jet ventilation in reducing respiratory motion for radiotherapy

Résumé fourni par la source

Different non-invasive ventilation techniques have been investigated in conscious subjects for respiratory motion reduction for radiotherapy instead of anesthesia and neuromuscular relaxation. However, those different techniques have not been compared within a single cohort. Here we compared the effect of non-invasive pressure-controlled mechanical ventilation (NIMV) and non-invasive high-frequency jet ventilation (HFJV) on diaphragm motion. Twenty-two healthy, conscious, unmedicated volunteers with no prior experience of non-invasive ventilation, and complying with appropriate in- and exclusion criteria for non-invasive ventilation and magnetic resonance imaging (MRI) participated. All volunteers practiced NIMV at a frequency of 60 min −1 with PEEP of 15 cm H 2 O and HFJV at frequencies of 60, 150, 250 and 400 min −1 . Ultrasound movies of 40s were acquired during NIMV and HFJV. We determined overall maximum diaphragm motion as the distance between its maximum end-inspiration and end-expiration position, sonographically. MR images were made during free breathing (FB) and NIMV. We monitored oxygen saturation (SpO 2 ), heart rate, blood pressure and end-tidal CO 2 . Finally, we assessed subjects' comfort with questionnaires (0, not comfortable; 4, highly comfortable). NIMV results in smallest overall maximum motion with median 9.7 mm compared to 34.9 mm during FB. HFJV maximally reduced diaphragm motion to 13.6 mm at 400 min −1 . Hemodynamic and respiratory variables showed significant but clinically irrelevant differences in SpO 2 between FB, NIMV 60 , and HFJV, and in end-tidal CO 2 and blood pressure between FB and NIMV 60 . Comfort scores were not significantly different between all sessions (median, 3; p = 0.156). HFJV reduces diaphragm motion, but NIMV results in smallest overall maximum motion, shows no relevant changes to hemodynamic and respiratory variables and is comfortable. Therefore, NIMV appears superior over HFJV for respiratory motion reduction for radiotherapy. These ventilation techniques can be applied without anesthesia, but anesthesiologic expertise is required to implement those techniques safely into clinical radiotherapy practice. • Non-invasive mechanical and jet ventilation in 22 conscious volunteers • Compared different ventilation techniques on motion reduction for radiotherapy. • Pressure-controlled ventilation at 60 min −1 with a high PEEP reduced motion most. • Mechanical ventilation and jet ventilation were rated as comfortable. • Anesthesia expertise is required to improve ventilation strategies for radiotherapy.

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