Predictive clinical utility of pre-hospital point of care lactate for transfusion of blood product in patients with suspected traumatic haemorrhage: derivation of a decision-support tool

Abstract

Introduction Pre-hospital emergency medical teams can transfuse blood products to patients with suspected major traumatic haemorrhage. Common transfusion triggers based on physiological parameters have several disadvantages and are largely unvalidated in guiding pre-hospital transfusion. The addition of pre-hospital lactate (P-LACT) may overcome these challenges. To date, the clinical utility of P-LACT to guide pre-hospital blood transfusion is unclear. Methods A retrospective analysis of patients with suspected major traumatic haemorrhage attended by Air Ambulance Charity Kent Surrey Sussex (KSS) between 8 July 2017 and 31 December 2019. The primary endpoint was the accuracy of P-LACT to predict the requirement for any in-hospital (continued) transfusion of blood product. Results During the study period, 306 patients with suspected major traumatic haemorrhage were attended by KSS. P-LACT was obtained in 194 patients. In the cohort 103 (34%) patients were declared Code Red. A pre-hospital transfusion was commenced in 124 patients (41%) and in-hospital transfusion was continued in 100 (81%) of these patients, in 24 (19%) patients it was ceased. Predictive probabilities of various lactate cut-off points for requirement of in-hospital transfusion are documented. The highest overall proportion correctly classified patients were found for a P-LACT cut-point of 5.4 mmol/L (76.50% correctly classified). Based on the calculated predictive probabilities, optimal cut-off points were derived for both the exclusion- and inclusion of the need for in-hospital transfusion. A P-LACT < 2.5 mmol/L had a sensitivity of 80.28% and a negative likelihood ratio [LR−] of 0.37 for the prediction of in-hospital transfusion requirement, whereas a P-LACT of 6.0 mmol/L had a specificity of 99.22%, [LR−] = 0.78. Conclusion Pre-hospital lactate measurements can be used to predict the need for (continued) in-hospital blood products in addition to current physiological parameters. A simple decision support tool derived in this study can help the clinician interpret pre-hospital lactate results and guide pre-hospital interventions in the major trauma patient.

Identifying Trigger Cues for Hospital Blood Transfusions Based on Ensemble Learning Methods

“…This is consistent with recent study by Griggs et al who also predicted in hospital transfusion using prehospital lactate concentration. 15 Administration of prehospital blood products to patients in hemorrhagic shock reduces mortality. 4 A systematic review and meta-analysis by Rijnhout et al describes the administration of prehospital blood products as feasible and safe but describes the evidence as low quality and di cult to compare because there are no standard indication for transfusion.…”

Low‐titer group O whole blood in military ground ambulances: Lessons from the Israel Defense Forces initial experience

“…Balancing the risks and benefits of whole blood administration could be informed by research evaluating the sensitivity and specificity of prehospital signs dictating hemorrhagic shock, and investigations of additional measures to reliably assess volume status such as point-of-care ultrasound or point of care lactate measurement. 43,44 The thresholds for storage time and Anti-A and Anti-B titers utilised in this deployment were stringent, as to reduce the risk of adverse events or potentially diminishing efficacy of LTOWB during this preliminary rollout. Although use of these thresholds was implemented as to reduce the likelihood of adverse transfusion-related reactions or reduced hemostatic activity, 45 the low antibody (<1:100 titer) and storage-time (14-days from receipt by the ICU ambulances) thresholds may be currently unsuitable for larger-scale operational use.…”

“…Importantly, administration of whole blood by paramedic‐led teams requires policy change, 20 and we thus instituted several stopgaps to ensure proper and indicated administration. Balancing the risks and benefits of whole blood administration could be informed by research evaluating the sensitivity and specificity of prehospital signs dictating hemorrhagic shock, and investigations of additional measures to reliably assess volume status such as point‐of‐care ultrasound or point of care lactate measurement 43,44 …”

Adopting a culture of remote damage control resuscitation in the military: Insights from the Israel defense forces decade of experience

“…51 Looking ahead, there is a need to develop and validate simple, non-invasive methods for assessing tissue perfusion in the field, thus optimizing the balance of maintaining tissue oxygenation while minimizing the risk for rebleeding before proper hemorrhage control has been achieved. 38 Decision support tools, such as point-ofcare ultrasound 52 or lactate measurments 53 and field monitoring of measures, such as pulse pressure variation, 54 may assist providers in triaging casualties more objectively and identify casualties most urgently requiring volume resuscitation.…”