Gunnar Strandberg

Analysis of intraosseous samples using point of care technology—An experimental study in the anaesthetised pig

BACKGROUND Intraosseous access is an essential method in emergency medicine when other forms of vascular access are unavailable and there is an urgent need for fluid or drug therapy. A number of publications have discussed the suitability of using intraosseous access for laboratory testing. We aimed to further evaluate this issue and to study the accuracy and precision of intraosseous measurements. METHODS Five healthy, anaesthetised pigs were instrumented with bilateral tibial intraosseous cannulae and an arterial catheter. Samples were collected hourly for 6h and analysed for blood gases, acid base status, haemoglobin and electrolytes using an I-Stat point of care analyser. RESULTS There was no clinically relevant difference between results from left and right intraosseous sites. The variability of the intraosseous sample values, measured as the coefficient of variance (CV), was maximally 11%, and smaller than for the arterial sample values for all variables except SO2. For most variables, there seems to be some degree of systematic difference between intraosseous and arterial results. However, the direction of this difference seems to be predictable. CONCLUSION Based on our findings in this animal model, cartridge based point of care instruments appear suitable for the analysis of intraosseous samples. The agreement between intraosseous and arterial analysis seems to be good enough for the method to be clinically useful. The precision, quantified in terms of CV, is at least as good for intraosseous as for arterial analysis. There is no clinically important difference between samples from left and right tibia, indicating a good reproducibility.

Analysis of intraosseous samples in endotoxemic shock – an experimental study in the anaesthetised pig

Intraosseous (IO) access is used in emergency situations to allow rapid initiation of treatment. IO access is also sometimes used for blood sampling, although data on accuracy of such sampling in critical illness are limited. There is also a potential risk that bone marrow fragments in IO samples may damage laboratory equipment. It is ethically questionable to perform a simultaneous comparison between IO and arterial/venous sampling in critically ill humans. We have, thus, studied the analytical performance of IO sampling in a porcine septic shock model using a cartridge‐based analyser.

Intraosseous samples can be used for opioid measurements--an experimental study in the anaesthetized pig.

Abstract Aim. The intraosseous route provides access to the systemic circulation in an emergency situation when other forms of vascular access are unavailable and there is an urgent need for fluid or drug therapy. The intraosseous access has also been used for collecting samples for laboratory testing. A question that may arise in an unconscious or severely exhausted patient is whether this condition is caused by an unknown drug. We aimed to evaluate whether intraosseous samples could be used to measure opioids and to study the accuracy and precision of such measurements. Methods. Five healthy, anaesthetized pigs were treated with a continuous morphine infusion as part of the anaesthesia procedure. Samples for morphine testing were collected hourly for 6 h from two tibial intraosseous cannulae and a central venous catheter. Results. The differences in morphine concentrations between the two tibial intraosseous cannulae were less than 10% in 32/33 times. The values were also relatively stable over time. Conclusion. Our findings suggest that intraosseous samples can be used for the analysis of opioids if an IV route is not available.

Intraosseous and intravenous administration of antibiotics yields comparable plasma concentrations during experimental septic shock

We aimed to investigate whether comparable antibiotic concentrations could be reached with intraosseous and intravenous administration during septic shock.

Evaluation of intraosseous sampling for measurements of alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, creatinine kinase, gamma-glutamyl transferase and lactate dehydrogenase.

Abstract Background: Intraosseous (IO) access can be established faster than a venous or arterial access when there is an urgent need for rapid initiation of treatment. The access can also be used to draw marrow samples. The aim of the present study was to evaluate the potential use of IO samples for enzyme determinations using a porcine model. Materials and methods: Bilateral tibial intraosseous cannulae and an arterial catheter were used for blood sampling from five healthy anesthetized pigs. Samples were collected at baseline and thereafter hourly for 6 h and analyzed for alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, creatinine kinase, gamma-glutamyl transferase and lactate dehydrogenase. Results: Creatinine kinase, lactate dehydrogenase and alkaline phosphatase levels decreased over time. The differences between IO and arterial sampling were limited for all studied markers. Conclusion: The correlation between marrow and blood analysis for liver function tests and CK is sufficiently accurate in an emergency situation.

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

BackgroundLaboratory 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.MethodsTen 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.ResultsBleeding 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.DiscussionThe 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.ConclusionsAlthough 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.