Interesting to me as I’ve never heard that named event.
This phenomenon of fentanyl-induced respiratory muscle rigidity (FIRMR) and laryngospasm is clinically known as wooden chest syndrome (WCS), which occurs within 1 to 2 minutes after injection and lasts ∼8–15 minutes (Grell et al., 1970; Scamman, 1983; Streisand et al., 1993).
Noradrenergic Mechanisms in Fentanyl-Mediated Rapid Death ...
nih.gov
https://www.ncbi.nlm.nih.gov › articles › PMC6863461
longer term non-injected fentanyl dosing/non-clearance of metabolites leads to a form of induced pulmonary edema (lungs flood with non-filtered/excreted water/solubles) result being that pronounced anoxia (a-oxygenation) aggravates the already contracted cardiac blood supply (with poorly oxygenated blood resulting from the non-absorption of oxygen from outside air/lungs to the blood).
Some analysis (non-court) of audio states that rales— rattling gurgling sounds from the lungs can be heard from the individual. If the build up of fluid continues to within the pericardial sac— death is rather rapidly to follow without a pericardial syringe draw off of the fluid constraining the heart motion.