Analysing blood from intraosseous access: a systematic review.

Intraosseous (IO) access is used widely as an optional vascular route for critically ill patients. It is still unclear whether the IO access can be used as a source for emergency blood samples. The aim of this study was to systematically review the existing literature on the usability of IO blood samples for analysing the parameters relevant to emergency care. We performed a data search from the Medline and Embase databases, the Cochrane Library and the Clinical trials registry. Animal studies and studies with healthy and ill adults and children were included in the search. The data were collected and reported following the PRISMA guidelines. The PROSPERO database registration number of this review is CRD42017064194. We found 27 studies comparing the blood samples from the IO space with arterial or venous samples, but only three of them followed the recommended guidelines for method comparison studies. The study populations were heterogeneous, and the sample sizes were relatively small (14, 17 and 20 individuals) in the three studies. The results of specific laboratory parameters were scarce and discordant. The evidence on the agreement between IO and arterial and venous samples is still weak. Existing studies with healthy volunteers and animal models provide important insight into the analyses of IO samples, but more evidence, especially from haemodynamically unstable patients, is needed for wider implementation of IO blood sampling in critically ill patients.