Pre‐hospital central venous access for major trauma: a reply

We thank Mathais et al. [1] and O'Sullivan et al. [2] for their constructive comments on our study [3]. Rapid access to definitive haemorrhage control is paramount. However, in patients in profound haemorrhagic shock or at imminent risk of traumatic cardiac arrest, obtaining large-bore intravenous access to enable effective blood resuscitation can be the single most important pre-hospital intervention, as it may prevent cardiac arrest before haemorrhage control is achieved. In non-compressible torso haemorrhage, a focused attempt at intravenous access is therefore the only procedure for which a time penalty is justified. Where technical ability is available, central access is a logical choice because peripheral access might be unachievable, repeated attempts are time-consuming and intraosseous flow rates are inadequate for meaningful transfusion in adults who are severely shocked. Mathais et al. and O'Sullivan et al. question whether this translates into meaningful outcome differences. In our cohort, patients with successful central venous access received markedly higher transfusion volumes and were twice as likely to reach hospital alive. Those in traumatic cardiac arrest were also more likely to achieve return of spontaneous circulation. Among patients who were not in cardiac arrest before team arrival, survival was higher in the central-access group (83, 35% vs. 18, 27%). That said, the numbers are small and our sample size was insufficient to determine whether this was a significant difference. Interpretation of survival to discharge requires caution because many subsequent deaths relate to non-haemorrhagic causes, including hypoxic and traumatic brain injury, and a greater proportion (13% vs. 4%) of the successful central venous access group were already in traumatic cardiac arrest on arrival. These findings should be viewed within the wider system context. It is established that most deaths from trauma occur before hospital arrival in mature trauma systems and that haemorrhage is the leading cause of preventable mortality [4]. Our recent unpublished analysis of deaths from trauma in London aligns with this: early 80% of patients who died had suffered a pre-hospital traumatic cardiac arrest, and 96% of deaths due to haemorrhage occurred in the pre-hospital phase. The greatest opportunity to prevent avoidable deaths from trauma therefore is before patients reach definitive care [5]. Early survival and successful resuscitation are appropriate outcome measures for interventions aimed at exsanguinating haemorrhagic shock [6]. Mathais et al. and O'Sullivan et al. also comment on technique, particularly the use of a landmark subclavian approach. In our system, the subclavian vein is preferred in extremis because its predictable anatomical location supports rapid landmark-guided insertion when the use of ultrasound would introduce delay. Clinicians are encouraged to use whichever site they believe can be achieved most quickly and safely, whether that be subclavian, internal jugular or femoral, and with ultrasound available when required. With regard to complications, unrecognised events among patients dying on scene cannot be excluded, and this emphasises the importance of robust governance, including focused clinical–pathological correlation review of this extremely sick group. Pre-hospital trauma line insertion is therefore a targeted intervention for a small cohort in whom peripheral access is unachievable and early blood resuscitation may prevent cardiac arrest, supporting early survival in the phase of care where most deaths from haemorrhage occur.