Microcirculatory Evaluation of Crystalloids, Fresh Frozen Plasma, Hemoglobin Based Oxygen Carriers, and Pack Red Blood Cells in Trauma Hemorrhagic Shock
Authors: Martinez Jacinda , Munoz Carlos , Lucas Daniela , R. Muller Cynthia , Cabrales Pedro 
Published: May 2024

Introduction: The prehospital management of traumatic injuries has significantly evolved since the establishment of emergency medical services in the 1970s. Initially focused on using crystalloid solutions, experiences in military and civilian trauma care have shifted towards balanced blood components for immediate blood replacement, known as remote damage control resuscitation (RDCR). This shift led to the adoption of prehospital transfusion, with packed red blood cells (pRBC) showing increased survival rates upon hospital arrival but no overall increase in survival. Additionally, fresh frozen plasma (FFP) and its timing of administration remain controversial. The development of hemoglobin-based oxygen carriers (HBOCs) aims to rival blood products, offering logistical advantages and potential to replace pRBC and FFP in challenging accessibility scenarios. This study investigates HBOCs' effcacy during hemorrhagic shock, hypothesizing their comparability to crystalloids, pRBC, and FFP in microcirculatory function. Methods:. To study the effcacy of HBOCs during hemorrhagic shock, Golden Syrian hamsters were instrumented with a dorsal window chamber, and catheters in the left common carotid artery, the animals were hemorrhaged for 50% of their blood volume (estimated as 7% of body weight) and resuscitated with 25% of their blood volume with LR, FP, HBOC, or pRBC. Shock was monitored for 30 minutes while resuscitation was monitored for 1 hour. Microvascular perfusion was characterized by vessel diameter, flow, and functional capillary density. Systemic variables were characterized as mean arterial pressure (MAP), heart rate (HR), and blood chemistry. Results: Across all animals, the baseline mean arterial pressure (MAP) and heart rate (HR) averaged 112.69 ± 11.16 mmHg and 404.44 ± 45.78 beats per minute (BPM), respectively. During shock, these values decreased to 50.76±11.57 mmHg and 379.36±60.49 BPM. Post-resuscitation using LR, FP, or HBOC, the MAP showed increases of 12%, 20%, and 44%, respectively. However, there were no significant changes observed in the HR. The HBOC group notably demonstrated the most substantial increase in MAP following shock. Arteriole diameter, both less than and greater than 60 μm, did not reveal any statistically significant differences between the HBOC group, except for the pRBC group, which showed larger diameters than the HBOC group after an hour post-resuscitation in arterioles < 60 μm. The arteriole flow in the HBOC group averaged a flow rate of 2.42 nL/s, compared to LR (0.13 nL/s), FP (1.30 nL/s), and pRBC (3.64 nL/s) in arterioles > 60 after an hour post-resuscitation, showing similar statistically significant differences in the HBOC group after the 60-minute post-resuscitation period. Conclusion: HBOCs exhibit promising potential as a resuscitation fluid for immediate blood replacement, not only due to their logistical advantages over blood component therapy but also for their ability to maintain more stable MAPs and better blood flow through small arterioles compared to component therapies. Project number: R01HL159862 Project number: R01HL162120. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.