...correcting the link.
Thank you for that link!
It is worth reading all the way through. The following suggests that the position used by the officer may not be a cause of his death.
“Based on these findings, PMRP may result in a transient pattern of restricted pulmonary function, but the lack of evidence for hypoxia or hypoventilation suggests that factors other than body positioning appear to be more important determinants for sudden, unexpected death. Nonetheless, respiratory muscle fatigue resulting from exertion and struggle against restraints (exertion vs. position asphyxia) cannot be excluded nor can potentially fatal pre-existing problems with central cardiac output, oxygen saturation, or oxygen use.6,26,28,34”