A biophysical vascular bubble model for devising decompression procedures. Issue 6 (21st March 2017)

• Record Type: Journal Article
• Authors: Arieli, Ran; Marmur, Abraham
• Is Part Of: Physiological reports. Volume 5:Issue 6(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-03-21
• Subjects: Active hydrophobic spot -- arterial bubbles -- bubble expansion -- decompression illness; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.13191
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Vascular bubble models, which present a realistic biophysical approach, hold great promise for devising suitable diver decompression procedures. Nanobubbles were found to nucleate on a flat hydrophobic surface, expanding to form bubbles after decompression. Such active hydrophobic spots (AHS) were formed from lung surfactants on the luminal aspect of ovine blood vessels. Many of the phenomena observed in these bubbling vessels correlated with those known to occur in diving. On the basis of our previous studies, which proposed a new model for the formation of arterial bubbles, we now suggest the biophysical model presented herein. There are two phases of bubble expansion after decompression. The first is an extended initiation phase, during which nanobubbles are transformed into gas micronuclei and begin to expand. The second, shorter phase is one of simple diffusion‐driven growth, the inert gas tension in the blood remaining almost constant during bubble expansion. Detachment of the bubble occurs when its buoyancy exceeds the intermembrane force. Three mechanisms underlying the appearance of arterial bubbles should be considered: patent foramen ovale, intrapulmonary arteriovenous anastomoses, and the evolution of bubbles in the distal arteries with preference for the spinal cord. Other parameters that may be quantified include age, acclimation, distribution of bubble volume, AHS, individual sensitivity, and frequency of bubble formation. We believe that the vascular bubble model we propose adheres more closely to proven physiological processes. Its predictability may therefore be higher than other models, with appropriate adjustments for decompression illness (DCI) data. Abstract : A comprehensive vascular bubble model is proposed for the construction of decompression procedures. This is based on the presence of active hydrophobic spots (AHS), composed of surfactant that has leaked from the lung, at which bubbles nucleate and expand. A new mode of distal arterial bubble formation is suggested, with the focus on the spinal cord. Data ranges are provided for bubble initiation, expansion, volume on detachment, activation of the AHS, and individual sensitivity.