Pre‐hospital central venous access for major trauma

We read with interest the article by Pallavicini et al., who examined the feasibility, efficacy and safety of pre-hospital placement of a trauma line in patients with exsanguinating haemorrhagic shock [1]. We commend the authors for addressing an under-investigated yet highly relevant intervention in the pre-hospital setting. Peripheral intravenous catheter insertion may be challenging in patients with traumatic injuries [2] and central venous catheter techniques offer a solution. Their results as reported are compelling. Although successful trauma line insertion correlated with increased survival on arrival at the emergency department, no statistically significant difference in survival to hospital discharge was found. It could therefore be argued that the intervention prolongs survival to admission without altering longer term outcomes. Given the observational nature of the study, confounding and selection biases are inevitable. The London Air Ambulance team is highly skilled clinicians and these findings may not translate to other pre-hospital systems with differing levels of expertise. Experience in central venous catheter insertion varies between individuals and attempting the procedure may reflect favourable anatomy or operator confidence. Only 4% of patients had a trauma line attempted, which represents a highly selective subset. More information on patients who did not receive a trauma line attempt would strengthen external validity. The 80% success rate for pre-hospital trauma line insertion is impressive under the described conditions. While the authors reference in-hospital central venous catheter success rates of 88–93%, a recent meta-analysis showed in-hospital success rates are approximately 98% [3]. The 4% complication rate among transported patients is likewise excellent and comparable with the 3% major complication rate seen in hospital practice [3]. The relatively high failure rate of 20% likely reflects the challenges posed by the pre-hospital environment rather than operator underperformance. The high competence of the London Air Ambulance team again raises questions about broader applicability. The primary outcome of successful insertion was defined as smooth guidewire passage, catheter insertion and unobstructed aspiration. This definition is pragmatic, although cases of arterial placement could have been missed due to an absence of pulsatile flow in patients with profound shock and the unavailability of ultrasound imaging. We only know the success rate of the patients that made it to hospital. Not including patients who died on the scene may underestimate adverse events due to survivorship bias. Most patients (75%) had no intravenous access before team arrival; however, the proportion of patients in which a peripheral intravenous catheter was later achieved is not reported. In practice, large-bore peripheral access may fulfil early resuscitation needs quicker and the authors rightly conclude that trauma lines form part of a care bundle including transfusion and definitive haemorrhage control. They should be viewed as one component of advanced pre-hospital systems capable of carrying large-volume blood products, real-time monitoring and rigorous governance. The study shows that, in a high-performance, physician-led urban pre-hospital service, trauma line insertion is feasible, allows higher pre-hospital transfusion volumes and carries acceptable procedural risk. For systems with the required personnel, training and logistics, trauma lines are an alternative to a peripheral intravenous catheter in exsanguinating trauma. However, generalising this approach requires caution as the benefits must be weighed against potential delays, operator skill and system capability for transfusion logistics.