Mark Bloch

Haemostatic dressings in prehospital care

Massive haemorrhage still accounts for up to 40% of mortality after traumatic injury. The importance of limiting blood loss after injury in order to prevent its associated complications has led to rapid advances in the development of dressings for haemostatic control. Driven by recent military conflicts, there is increasing evidence to support their role in the civilian prehospital care environment. This review aims to summarise the key characteristics of the haemostatic dressings currently available on the market and provide an educational review of the published literature that supports their use. Medline and Embase were searched from start to January 2012. Other sources included both manufacturer and military publications. Agents not designed for use in prehospital care or that have been removed from the market due to significant safety concerns were excluded. The dressings reviewed have differing mechanisms of action. Mineral based dressings are potent activators of the intrinsic clotting cascade resulting in clot formation. Chitosan based dressings achieve haemostasis by adhering to damaged tissues and creating a physical barrier to further bleeding. Acetylated glucosamine dressings work via a combination of platelet and clotting cascade activation, agglutination of red blood cells and local vasoconstriction. Anecdotal reports strongly support the use of haemostatic dressings when bleeding cannot be controlled using pressure dressings alone; however, current research focuses on studies conducted using animal models. There is a paucity of published clinical literature that provides an evidence base for the use of one type of haemostatic dressing over another in humans.

An evaluation of a new prehospital pre-alert guidance tool

Background The requirement for guidance regarding ambulance crews pre-alerting patients into hospital emergency departments (ED) has been well established, but a clear guidance tool that supports a decision to pre-alert a receiving hospital is lacking. Aims To investigate the impact of a new pre-alert tool on current alerting practice and evaluate its ability to take the place of a prehospital early warning system. Methods Data were collected for a sample of patients brought by ambulance to the resuscitation area of Aberdeen Royal Infirmary ED over a 7-week period. Basic demographic information plus alert status and guidance prompt status was collected and compared with a pragmatic alert requirement. Analysis of ambulance crew alert decisions and the pre-alert guidance prompt advice was undertaken and compared. Results Ambulance crew decisions to alert had a sensitivity of 72% (CI 62% to 80%), specificity of 50% (CI 27% to 73%), positive predictive value (PPV) of 90% and negative predictive value (NPV) of 22%. The pre-alert guidance alert prompt had a sensitivity of 99% (CI 94% to 100%), specificity of 64% (CI 39% to 84%), PPV of 95% and NPV of 90%. 28% of patients were under-alerted by ambulance crews, mostly medical patients presenting with chest pain. Conclusions The pre-alert guidance tool shows face validity and superior ability to advise a pre-alert than ambulance crew decisions. It supplements a practitioners’ clinical decision-making and has been regarded as having a positive impact on ED triage and utilisation of resources. Further levels of validity are expected to be achieved with continued audit and ongoing use of this tool.

Prehospital spinal immobilisation: an initial consensus statement

Spinal injuries are thankfully relatively uncommon but have the potential to cause very signiEcant morbidity and mortality. It is reported that between 0.5% and 3% of patients presenting with blunt trauma suffer spinal cord injury (SCI). The incidence varies globally and time has yielded increased numbers of injuries annually. American Egures estimate an incidence in the region of 40 cases per million per year. In the UK, the majority of traumatic SCI are attributable to land transport (50%), followed by falls (43%), then sport (7%). Of those fractures causing SCI, half involve fractures of the cervical spine, with 37% due to thoracic spine injury and 11% due to lumbar spine injury. Of the C-spine, 50% occur at the C6/7 junction and a third at C2. Data show a crossover rate in the region of 10%–15% of patients with a conErmed cervical fracture also having a thoracolumbar fracture. It is well recognised that immobilisation is not without harm but the ‘number needed to treat’ in order to include one actual injury is high. SCI occurs when unstable spinal fractures (only diagnosed by imaging in hospital) cause direct mechanical damage as a result of traction and compression, following which ischaemia and cord swelling ensues. Unstable fractures are those where there is disruption of two or three vertebral columns. The anterior column is formed by the anterior longitudinal ligament and the anterior half of the vertebral body, disc and annulus, the middle column by the posterior half of the vertebral body, disc and annulus and the posterior longitudinal ligament and the posterior column by the facet joints, ligamentum Favum, the posterior elements and the interconnecting ligaments. Immobilisation is based on the logical premise that preventing movement should decrease the incidence of SCI or further deterioration of existing damage. This is undertaken by, in effect, adding external supports to the body, preventing secondary injury during extrication, resuscitation, transport and evaluation. Immobilisation is a routinely performed procedure in the prehospital environment. Its potentially serious adverse sequelae and the litigious nature of modern medicine have seen the development of an extraordinarily conservative approach to immobilisation where it is applied in many cases in which neither the mechanism of injury nor the clinical Endings would support its use. Methods vary and research has drawn together consensus opinion on immobilisation techniques. Common practice involves the use of a rigid cervical collar, head blocks with straps or tapes and a long board with straps. A number of organisations use the orthopaedic scoop stretcher or Kendrick Extrication Device. The scoop stretcher is of value in reducing the amount of handling to which victims of trauma are subjected and the Faculty of Pre-Hospital Care is shortly to issue consensus guidance regarding minimal handling protocols in trauma. The vacuum mattress is indicated in prolonged transportation to minimise the risks explained below. A pelvic sling should therefore be placed in the correct position in the vacuum mattress and the patient transferred in the scoop onto the mattress and the pelvic binder fastened appropriately. Once on a vacuum mattress, the scoop can be removed in such prolonged transfers.

The prehospital management of pelvic fractures: initial consensus statement

INTRODUCTION Serious pelvic injuries are associated with a high mortality rate, 2 which has remained persistently high even with advances in hospital care. Hypovolaemia is often a significant contributing factor to these deaths 3 If haemorrhage from pelvic injuries could be controlled or reduced in the prehospital environment, then survival rates might increase. Improved mortality has been seen with catastrophic haemorrhage from limb injuries after the introduction of the battlefield tourniquet and topical haemostatic dressings. However, compared with bleeding from pelvic injuries, external haemorrhage is simple to recognise and the success of intervention easier to observe. Pelvic binding devices provide a simple alternative to surgical fixators. These devices can be applied in the prehospital environment, potentially allowing control of unseen major haemorrhage. This article reports the finding of a consensus meeting on the prehospital management of pelvic injuries held in March 2012 and examines the evidence associated with pelvic binding devices and their application.