Use of intraosseous blood for repeated hematologic and biochemical analyses in healthy pigs

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.

Intraosseous blood samples for point-of-care analysis: agreement between intraosseous and arterial analyses

Background

Point-of-care (POC) testing is highly useful when treating critically ill patients. In case of difficult vascular access, the intraosseous (IO) route is commonly used, and blood is aspirated to confirm the correct position of the IO-needle. Thus, IO blood samples could be easily accessed for POC analyses in emergency situations. The aim of this study was to determine whether IO values agree sufficiently with arterial values to be used for clinical decision making.

Methods

Two samples of IO blood were drawn from 31 healthy volunteers and compared with arterial samples. The samples were analysed for sodium, potassium, ionized calcium, glucose, haemoglobin, haematocrit, pH, blood gases, base excess, bicarbonate, and lactate using the i-STAT® POC device. Agreement and reliability were estimated by using the Bland-Altman method and intraclass correlation coefficient calculations.

Results

Good agreement was evident between the IO and arterial samples for pH, glucose, and lactate. Potassium levels were clearly higher in the IO samples than those from arterial blood. Base excess and bicarbonate were slightly higher, and sodium and ionised calcium values were slightly lower, in the IO samples compared with the arterial values. The blood gases in the IO samples were between arterial and venous values. Haemoglobin and haematocrit showed remarkable variation in agreement.

Discussion

POC diagnostics of IO blood can be a useful tool to guide treatment in critical emergency care. Seeking out the reversible causes of cardiac arrest or assessing the severity of shock are examples of situations in which obtaining vascular access and blood samples can be difficult, though information about the electrolytes, acid-base balance, and lactate could guide clinical decision making.

The analysis of IO samples should though be limited to situations in which no other option is available, and the results should be interpreted with caution, because there is not yet enough scientific evidence regarding the agreement of IO and arterial results among unstable patients.

Conclusions

IO blood samples are suitable for analysis with the i-STAT® point-of-care device in emergency care. The aspirate used to confirm the correct placement of the IO needle can also be used for analysis. The results must be interpreted within a clinical context while taking the magnitude and direction of bias into account.

Analysis of thromboelastography, PT, APTT and fibrinogen in intraosseous and venous samples-an experimental study

Background

Laboratory analysis of coagulation is often important in emergencies. If vascular access is challenging, intraosseous catheterization may be necessary for treatment. We studied the analysis of coagulation parameters in intraosseous aspirate during stable conditions and after major haemorrhage in a porcine model.

Methods

Ten anesthetized pigs received central venous and intraosseous catheters and samples were taken for analysis of thromboelastography (TEG), prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen concentration. Analyses were repeated after removal of 50 % of the calculated blood volume and resuscitation with crystalloid. Intraosseous and venous values were compared.

Results

Bleeding and resuscitation resulted in haemodilution and hypotension. Median TEG reaction time was shorter in intraosseous than in venous samples before (1.6 vs 4.6 min) and after (1.6 vs 4.7 min) haemodilution. Median maximal amplitude was smaller in intraosseous samples at baseline (68.3 vs 76.4 mm). No major differences were demonstrated for the other TEG parameters. The intraosseous samples often coagulated in vitro, making analysis of PT, APTT and fibrinogen difficult. After haemodilution, TEG maximal amplitude and α-angle, and fibrinogen concentration, were decreased and PT increased.

Discussion

The intraosseous samples were clinically hypercoagulable and the TEG demonstrated a shortened reaction time. The reason for this may hypothetically be found in the composition of the IO aspirate or in the sampling technique. After 50 % haemorrhage and haemodilution, a clinically relevant decrease in fibrinogen concentration and a lower TEG maximal amplitude were observed.

Conclusions

Although the sample is small, these data indicate that intraosseous samples are hypercoagulable, which may limit their usefulness for coagulation studies. Major haemodilution only moderately affected the studied parameters.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-016-0318-0) contains supplementary material, which is available to authorized users.

Analysis of bone marrow aspiration fluid using automated blood cell counters

Cytomorphological examination of aspirate smears remains the basic method to diagnose hematologic disorders and to evaluate treatment-related changes. Last-generation hematological analyzers can count, besides cells normally circulating in peripheral blood, some types of immature and abnormal cells, such as erythroblasts and immature granulocytes. The complex nature of bone marrow fluid, however, has prevented until now the routine utilization of blood cell counters in this area. Recent studies have shown the possibility of using bone marrow fluid as a substitute for peripheral blood for clinical tests in particular situations and for repetitive cytologic examinations in specific clinical and research fields.