Could chest wall rigidity be a factor in rapid death from illicit fentanyl abuse?

Abstract

BACKGROUND: There has been a significant spike in fentanyl-related deaths from illicit fentanyl supplied via the heroin trade. Past fentanyl access was primarily oral or dermal via prescription fentanyl patch diversion. One factor potentially driving this increase in fatalities is the change in route of administration. Rapid intravenous (IV) fentanyl can produce chest wall rigidity. We evaluated post-mortem fentanyl and norfentanyl concentrations in a recent surge of lethal fentanyl intoxications. METHODS: Fentanyl related deaths from the Franklin County coroner's office from January to September 2015 were identified. Presumptive positive fentanyl results were confirmed by quantitative analysis using liquid chromatography tandem mass spectrometry (LC/MS/MS) and were able to quantify fentanyl, norfentanyl, alfentanyl, and sufentanyl. RESULTS: 48 fentanyl deaths were identified. Mean fentanyl concentrations were 12.5 ng/ml, (range 0.5 ng/ml to >40 ng/ml). Mean norfentanyl concentrations were 1.9 ng/ml (range none detected to 8.3 ng/ml). No appreciable concentrations of norfentanyl could be detected in 20 of 48 cases (42%) and were less than 1 ng/ml in 25 cases (52%). Elevated fentanyl concentrations did not correlate with rises in norfentanyl levels. In several cases fentanyl concentrations were strikingly high (22 ng/ml and 20 ng/ml) with no norfentanyl detected. DISCUSSION: The lack of any measurable norfentanyl in half of our cases suggests a very rapid death, consistent with acute chest rigidity. An alternate explanation could be a dose-related rapid onset of respiratory arrest. Deaths occurred with low levels of fentanyl in the therapeutic range (1-2 ng/ml) in apparent non-naïve opiate abusers. Acute chest wall rigidity is a well-recognized complication in the medical community but unknown within the drug abuse community. The average abuser of illicit opioids may be unaware of the increasing fentanyl content of their illicit opioid purchase. CONCLUSION: In summary we believe sudden onset chest wall rigidity may be a significant and previously unreported factor leading to an increased mortality, from illicit IV fentanyl use. Fentanyl and norfentanyl ratios and concentrations suggest a more rapid onset of death given the finding of fentanyl without norfentanyl in many of the fatalities. Chest wall rigidity may help explain the cause of death in these instances, in contrast to the typical opioid-related overdose deaths. Intravenous heroin users should be educated regarding this potentially fatal complication given the increasingly common substitution and combination with heroin of fentanyl.