Execution by lethal injection: Autopsy findings of pulmonary edema

Lethal injection is the common method of capital punishment in the United States (US), but problematic executions feed controversy centered on the 8th amendment of the US constitution that proscribes cruel punishment.[1][1] However, the definition of cruelty is contentious, and lethal injection displays few signs of the hidden course of a potentially cruel death. Few survive and those who die cannot give witness. In this study, we reviewed autopsy reports of prisoners executed by intravenous midazolam (usually followed by a neuromuscular blocking agent and potassium chloride) or pentobarbital as a single drug. Autopsy reports for 43 inmates obtained from eight states were reviewed to identify any abnormal findings. Pulmonary edema (often fulminant with froth filling airways) emerged as a consistent and unexpected abnormality in 33/43 autopsies (76.74%), 23/28 midazolam executions (82.14%), and 10/15 (66.66%) pentobarbital executions. Injecting heavy overdoses of either acidic or basic solutions into the bloodstream may be directly toxic to pulmonary capillary endothelial cells. The injury manifests by the sudden escape of edema fluid into normally air-filled lungs, resulting in pulmonary edema. These findings explain witnessed respiratory distress during executions and increase concern about an inability of an execution witness to observe such a finding when a paralytic is added. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The study received no funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The source of data are publicly available autopsy reports. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors. [1]: #ref-1