A Descriptive Analysis of Supermassive Transfusion Recipients Among US and Coalition Forces During Combat Operations in Afghanistan and Iraq

ABSTRACT Introduction Hemorrhage is the leading cause of potentially preventable death on the battlefield. Resuscitation with blood products is essential to restore circulating volume, repay the oxygen debt, and prevent coagulopathy. Massive transfusion (MT) occurs frequently after major trauma; a subset of casualties requires a supermassive transfusion (SMT), and thus, mobilization of additional resources remains unclear. Materials and Methods This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry. In this analysis, we isolated U.S. and Coalition casualties that received at least 1 unit of packed red blood cells (PRBCs) or whole blood (WB). Given a lack of consensus on the definition of SMT recipients, we included those patients receiving the top quartile of PRBC and WB administered within the first 24 hours following arrival to a military treatment facility. Results We identified 25,897 adult casualties from January 1, 2007 to March 17, 2020. Within this dataset, 2,608 (9.0%) met inclusion for this analysis. The median number of total products administered within the first 24 hours was 8 units of PRBC or WB. The upper quartile was 18 units (n = 666). Compared to all other blood product recipients, patients in the SMT cohort had a higher median injury severity score (27 vs 18, P < 0.001), were most frequently injured by explosives (84.9% vs 68.6%, P < 0.001), had a higher mean emergency department (ED) pulse (128 vs 111, P < 0.001), a lower mean systolic blood pressure (122 vs 132 mm Hg, P < 0.001), and a higher mean international normalized ratio (1.68 vs 1.38, P < 0.001). SMT patients experienced lower survival to hospital discharge (85.8% vs 93.3%, P < 0.001). Conclusions Compared to all other PRBC and WB recipients, SMT patients experienced more injury by explosives, severe injury patterns, ED vital sign derangements, and mortality. These findings may help identify those casualties who may require earlier aggressive resuscitation. However, more data is needed to define this population early in their clinical course for early identification to facilitate rapid resource mobilization. Identifying casualties who are likely to die within 24 hours compared to those who are likely to survive, may assist in determining a threshold for a SMT.

Peri-operative fluid management during neurosurgical procedures

The management of fluids and electrolytes in neurosurgical patients aims to reduce the risk of cerebral oedema, reduce ICP and at the same time maintain haemodynamic stability and cerebral perfusion. Neurosurgical patients commonly receive diuretics (mannitol and furosemide), developing complications such as bleeding and diabetes insipidus. These patients may require large volumes of intravenous fluids and even blood transfusions for volume resuscitation, treatment of cerebral vasospasm, correction of preoperative dehydration or maintenance of haemodynamic stability. Goal-oriented therapy is recommended in neurological patients, with the aim of maintaining circulating volume and tolerating the changes induced by anaesthesia (vasodilation and myocardial depression).

Acute and critical care echocardiography

This chapter covers the role of echocardiography in acute and critical care. This includes ‘front door’ echocardiography, the safeguarding of patient care, cardiopulmonary resuscitation, and acute diagnostics. The chapter then examines the circulating volume, fluid responsiveness, advanced haemodynamics, and special circumstances in the critically ill patient.

The Great Ormond Street Hospital immunoadsorption method for ABO-incompatible heart transplantation: a practical technique

Traditionally, ABO-incompatible heart transplantation was accomplished using a plasma exchange technique to remove recipient plasma containing donor-incompatible anti-A/B isohaemagglutinins. However, this technique exposed patients to large volumes of allogeneic blood and blood products (up to three times the patient’s circulating volume). In 2018, we published the first reported case of an ABO-incompatible heart transplant using an intraoperative immunoadsorption technique which minimises the exposure to blood products by specifically targeting anti-A/B isohaemagglutinins. We have subsequently used this technique in all children undergoing ABO-incompatible heart transplantation and become convinced of its efficacy in this population while observing no adverse effects. This article outlines the practical details required to perform the technique in order to avoid hyperacute rejection.

Water homeostasis

Under normal circumstances, the maintenance of water balance is a question of balancing urine output against oral water intake, after allowance for the largely unregulated loss of water through other routes (respiratory, transcutaneous, and via the gastrointestinal tract). Normally, this is managed by the feedback mechanisms controlling thirst and diuresis, but in a medical context it is important to allow for other forms of administration that may not be under the control of the patient, and other routes of fluid loss, such as haemorrhage and drains. Electrolyte and water homeostasis are closely interrelated: the major trigger for both antidiuretic hormone (vasopressin) release (and hence renal water retention) and thirst is plasma osmolality. Sodium and chloride are the major solutes in extracellular fluid so are major determinants of body water content and circulating volume.

Nontraumatic Intracranial Hemorrhage

Nontraumatic subarachnoid, intraventricular, or intraparenchymal hemorrhage can be caused by either rupture of an aneurysm or arteriovenous malformation or by coagulopathy, hypertension, or vasculitis. Pituitary apoplexy results from spontaneous hemorrhage or infarction into a pituitary tumor. Additionally, anesthesiologists must be prepared to manage intraoperative bleeding during craniotomies. Successful management of nontraumatic intracranial hemorrhage requires (1) careful preoperative evaluation and preparation considering extracranial manifestations of intracranial bleeding; (2) administration of balanced anesthesia to facilitate surgical exposure and neurophysiological monitoring; (3) maintenance of cerebral perfusion by preserving circulating volume, judicious use of blood product transfusion and vasopressors, and avoidance of excessive hyperventilation; and, when possible, (4) providing timely emergence from anesthesia to allow neurological assessment. Close communication between the surgical and anesthesia teams is critical for optimizing the potential for good patient outcomes.

Colloids in critical illness

Colloid solutions are homogenous mixtures of large molecules suspended in a crystalloid solution. The efficacy of colloids as volume substitutes or expanders, and length of effect are determined by their physicochemical properties. Smaller volumes of colloid than crystalloid are required for resuscitation. The primary use of colloids is in the correction of circulating volume. Rather than using fixed haemodynamic endpoints, fluid can be given in small aliquots with assessment of the dynamic haemodynamic response to each aliquot. The aim of a fluid challenge is to produce a small, but significant (200 mL) and rapid increase in plasma volume with changes in central venous pressure or stroke volume used to judge fluid responsiveness. Colloid fluids give a reliable increase in plasma volume to judge fluid responsiveness.