Control of massive haemorrhage

Exsanguination from catastrophic haemorrhage is the leading cause of preventable death – and a significant cause of morbidity – from trauma, and must be dealt with promptly. It is classified as compressible and non-compressible. The majority of external or extremity bleeding can be controlled by methods such as compression, elevation and splinting. The mnemonic DDIT can be used to describe options for managing this type of haemorrhage: application of direct pressure to the bleeding site with a dressing, further direct pressure and superimposition of another dressing, Indirect pressure by compressing the relevant artery against a bone, and application of a tourniquet if the bleeding is from a limb. Suspected long bone fractures are reduced by splinting, and pelvic fractures by binding. Haemostatic agents are available in different forms, such as CELOX™-impregnated gauze, and can be applied to wounds to achieve haemostasis. Patients with suspected internal, non-compressible haemorrhage require rapid transfer to hospital for surgical intervention. The CRASH-2 (Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage 2) trial shows that intravenous administration of the antifibrinolytic agent tranexamic acid (TXA) is beneficial when given within 3 hours of injury occurring.

Airway/C-Spine

Once any catastrophic haemorrhage has been addressed, airway assessment and management can be undertaken. The NCEPOD ‘Trauma: who cares?’ report found ‘a high incidence’ (one in eight) of trauma patients ‘arriving at hospital with a partially or completely obstructed airway’, with management of the airway considered unsatisfactory in 7%, and of the unstable spine in 8.3%, of cases reviewed. Cervical spine problems should be suspected in patients affected by trauma involving a large transfer of energy or obvious injury to the neck. Stabilisation of the cervical spine, initially with manual in-line techniques, and subsequently with a collar (if there is no concern about the patient having raised intracranial pressure, ICP), blocks and scoop or vacuum mattress, should be done concurrently with airway management. Airway management in the pre-hospital setting is complex, and has been the subject of much debate, with little evidence available to foster standardisation of practice. Establishment of a patent airway is necessary prior to facilitating oxygenation (with supplementary oxygen) and ventilation. In a patient with a reduced conscious level, airway patency may be achieved with simple manoeuvres, such as jaw thrust and suctioning of debris from the airway, or the use of adjuncts, such as an oropharyngeal airway or supraglottic airway device. If these techniques are ineffective, endotracheal intubation may be necessary in order to secure a definitive airway. In addition to patient obtundity, other indications for advanced airway management include impending or actual airway obstruction, ventilatory compromise, severe agitation, anticipated clinical course (for example, evolving traumatic brain injury, or requirement for surgery) and humanitarian need (analgesia). Tracheal intubation does not usually improve outcome in patients who have suffered cardiac arrest. The NCEPOD ‘Trauma: who cares?’ report advocates ‘the provision of personnel with the ability to provide anaesthesia and intubation in the prehospital phase’, for which the AAGBI guideline on pre-hospital anaesthesia provides detailed guidance.

The aim of performing a rapid sequence induction (RSI) is to facilitate rapid emergency tracheal intubation for patients with intact airway reflexes, before they become hypoxic or aspirate, but the procedure is not without risk of complications, particularly in the pre-hospital environment and in a group of patients whose already unstable physiology may be further compromised by anaesthetic drugs. Guidelines advise that pre-hospital emergency anaesthesia (PHEA) should be performed by individuals who have ‘the same level of training and competence that would enable them to perform unsupervised emergency anaesthesia and tracheal intubation in the emergency department’, and ‘to the same standards as in-hospital emergency anaesthesia’, in terms of training, tools and techniques. Prior to undergoing PHEA, the patient’s pre-induction observations should be assessed (pulse, respiratory rate, gross neurology including pupils) and peri-anaesthetic non-invasive monitoring should measure heart rate, blood pressure, oxygen saturations, continuous waveform capnography and electrocardiography. The patient should also be adequately pre-oxygenated using high-flow oxygen for 3 minutes. Although there are a number of RSI protocols, a modified technique using intravenous fentanyl, ketamine and rocuronium in a 3:2:1 (unit drug per kilogram patient weight) ratio, or (1):1:1 ratio in more haemodynamically compromised patients, has been shown to be effective in achieving suitable intubating conditions. An opioid attenuates the hypertensive response to intubation (which is of particular benefit in patients with suspected head injury) and ketamine is a haemodynamically stable induction agent. Concerns regarding the use of ketamine for sedating patients with traumatic brain injury, in whom a high mean arterial pressure could exacerbate a potentially already raised ICP, have largely been disproved. Rocuronium at a dose of 1 mg/kg is a useful muscle relaxant for pre-hospital intubation and transfer of a trauma patient, because it has a rapid onset and long duration of action, but can be reversed pharmacologically if necessary. Careful preparation for PHEA, including arrangement of 360° access to the patient, organisation of a standardised ‘kit dump’ of drugs and equipment, and execution of a verbal challenge-response checklist to confirm drugs, equipment and intubation strategy should aid team performance. Using a video laryngoscope may assist intubation. Patients for whom intubation, and the failed intubation drill, is unsuccessful, or who have suffered severe facial injury or burns resulting in disrupted airway anatomy, may require a surgical airway. Current Difficult Airway Society (DAS) guidelines recommend the use of a scalpel, gum elastic bougie and endotracheal tube for this procedure. Once airway patency has been established, high-flow oxygen therapy can be commenced.

Breathing

A look, listen, and feel structure to assessment of breathing will help to elicit any obvious life-threatening chest injury that requires immediate treatment. However, the signs may be subtle, particularly in patients with a larger body habitus, and the mechanism of injury and patient physiology should always supplement physical examination findings. Some pre-hospital services also use a handheld ultrasound device to aid diagnosis of intrathoracic pathology. An open pneumothorax should be covered with a specialised chest seal with a one-way valve to allow the lung to reinflate without further ingress of air through the wound. A simple pneumothorax should not be treated, but a tension pneumothorax causing ventilatory and/or haemodynamic compromise needs to be decompressed. Open thoracostomy is more reliably effective than needle decompression, although the latter should still be attempted as the first line treatment for a tension pneumothorax in spontaneously ventilating patients. Insertion of a chest drain should follow an open thoracostomy, although should be avoided in the pre-hospital phase if possible (which is often the case for patients undergoing positive pressure ventilation), to avoid ‘prolongation of on-scene time; risks of kinking, blocking or falling out during transfers; and long-term infection risks with non-sterile insertion techniques’. A massive haemothorax should not be drained in the pre-hospital environment unless ventilation is severely affected, as doing so will result in significant loss of circulating volume.

High-flow oxygen is delivered to the patient via a face mask with a reservoir bag to an adequately spontaneously ventilating patient, or via a bag valve mask (BVM), or portable ventilator, for patients requiring varying degrees of additional support. Patients with suspected intracranial pathology, which evidence has shown may be apparent in patients with a traumatic mechanism of head injury and a pre-hospital Glasgow Coma Scale (GCS) score as high as 13 or 14, will benefit from intubation and ventilation, to optimise cerebral perfusion pressure by means of improved oxygenation and prevention of hypercarbia.

Circulation

The degree of blood loss can be gauged in part by assessing the patient’s observations, such as heart rate, non-invasive blood pressure, respiratory rate and capillary refill time. The mnemonic ‘blood on the floor and four more’ prompts consideration of potential internal sources of haemorrhage, in addition to obvious external blood loss, secondary to long bone fractures, pelvic fractures, intra-abdominal haemorrhage and intra-thoracic haemorrhage. Portable ultrasound may be used to facilitate diagnosis of internal haemorrhage in the pre-hospital environment, although it is an operator-dependent modality and should serve as an adjunt to, not a replacement for, clinical findings and acumen. Haemorrhage control is achieved by a variety of methods, as already discussed. Treatment of blood loss begins with establishment of either intravenous (preferably a large-bore cannula) or intraosseous (in the tibia, humeral head or sternum) access.

Damage control resuscitation (DCR) is synonymous with the concept of balanced resuscitation, and consists of permissive hypotension and haemostatic resuscitation, in order to establish survivable patient physiology before definitive injury repair can be achieved. Permissive hypotension involves maintaining a blood pressure that is low enough to reduce active haemorrhage, and the risk of clot disruption, prior to surgical control of bleeding being achieved, but high enough to preserve end-organ perfusion. A target systolic blood pressure threshold of 90 mmHg is raised for patients with suspected traumatic brain injury (TBI), to maintain cerebral perfusion pressure (CPP). A novel hybrid resuscitation strategy proposes limiting the duration of permissive hypotension to 60 minutes, to mitigate poor oxygen delivery and metabolic acidosis. In trauma, NICE recommends titration of volume resuscitation to achieve a palpable central pulse (with a less restrictive approach in a situation of suspected traumatic brain injury), using blood products in preference to any other fluid. Red cells, replacement of which will improve the oxygen-carrying capacity of the blood, and portable blood-warming devices are now carried by many pre-hospital services. Haemostatic resuscitation advocates early use of blood products in ratios similar to whole blood – red blood cells, plasma and platelets administered 1:1:1. The aim of this balanced strategy is to avoid complications associated with crystalloids, including dilution of red cell and coagulation factor concentrations, and exacerbation of acidosis, hypothermia, oedema and immune system activation causing cellular injury. RePHILL (Resuscitation with Pre-Hospital Blood Products) is a current multi-centre randomized controlled trial of pre-hospital blood product administration (red cells and lyophilized plasma) versus standard care (resuscitation with normal saline) for traumatic haemorrhage. It hypothezises an improvement in tissue perfusion and reduction in mortality in the blood product patient group. Research is also ongoing to assess the benefit of giving other products, such as cryoprecipitate (CRYOSTAT-2, Early Cryoprecipitate in Trauma 2) in the pre-hospital environment. A ‘code red’, indicating requirement for blood products, can be communicated ahead to the receiving hospital.

A pre-hospital resuscitative thoracotomy is indicated as part of the management of traumatic cardiac arrest in cases of suspected cardiac tamponade (most likely when there is penetrating chest trauma) or when proximal aortic compression may be needed to control catastrophic bleeding from subdiaphragmatic vascular injuries. The European Resuscitation Council Guidelines for Resuscitation 2015 advise that this procedure should only be performed by an appropriately skilled clinician, and that the time from loss of vital signs to commencing a resuscitative thoracotomy should not exceed 10 minutes. Resuscitative endovascular balloon occlusion of the aorta (REBOA) involves the temporary occlusion of the aorta, using a percutaneously deployed intravascular balloon which is usually inserted via the femoral artery, in order to halt non-compressible haemorrhage. The first pre-hospital REBOA procedure in the world was performed successfully by the London Air Ambulance in 2014, and the evidence base for the utility of the procedure is growing.

Disability

An assessment of the patient’s baseline neurological function, using the Alert, Voice, Pain, Unresponsive (AVPU) or GCS scales, as well as pupil size and reactivity, should be performed – particularly pre- and post-administration of anaesthetic drugs. In a patient with apparent or suspected TBI, measures taken to prevent secondary brain injury from hypoxia, hypercarbia and hypotension include intubation and ventilation, to better control oxygenation and ventilation (aiming for SaO ₂ ≥90% and PaCO ₂ 35–40 mmHg), and maintenance of an adequate blood pressure (systolic ≥100 mmHg for patients aged 50–69 years old or ≥110 mmHg for patients aged 15–49 or >70 years old), in order to counteract any (further) rise in ICP and reduction in CPP. The issue of blood pressure is more complex for patients with traumatic haemorrhage in addition to TBI. Brain Trauma Foundation guidelines state that a single pre-hospital episode of hypoxia (with SaO ₂ <90%) or hypotension (defined as systolic <90 mmHg) in a TBI patient is a statistically independent risk factor for a poor outcome. Other neuroprotective strategies for lowering ICP and maintaining CPP include taping, rather than tying, the endotracheal tube, applying head blocks without a hard collar, and positioning patients at 30° head up to assist cerebral venous drainage. Evidence has shown that intracranial pathology may be apparent in patients with a traumatic mechanism of head injury and a pre-hospital GCS as high as 13 or 14, and that these patients will benefit from being managed with the above precautions. If there are clinical signs of a raised ICP (such as a dilated pupil), infusion of intravenous hypertonic saline may help to reduce cerebral oedema by creating an osmotic gradient that draws intracerebral fluid into the systemic circulation, thereby reducing ICP and concurrently augmenting blood pressure for better CPP. Judicious sedation should reduce cerebral metabolic requirements and seizure activity. Careful management of TBI patients, including early institution of neuroprotective strategies, is crucial for preventing secondary brain injury and reducing associated morbidity and mortality. The patient’s blood glucose level and temperature should also be checked as soon as possible, and measures taken to establish normoglycaemia and prevent hyperthermia. The CRASH-3 (Clinical Randomisation of an Antifibrinolytic in Significant Head Injury 3) trial shows that intravenous TXA treatment within 3 hours of injury reduces head injury-related death.

Studies have indicated that acute pain in trauma is undertreated, even though early and effective treatment of pain will improve long-term outcomes, including reducing the incidence of chronic pain issues. Pain scores should be elicited and appropriately treated. Commonly used agents in the pre-hospital setting include ketamine, which has the advantage of not depressing cardiovascular or laryngeal reflexes as much as other sedative medication, opioids and the use of local anaesthetic nerve blocks. In the absence of intravenous or intraosseous access it is possible to administer intranasal diamorphine or ketamine or intramuscular ketamine. An inhalational agent, methoxyflurane, is a well-established analgesic in Antipodean pre-hospital practice, but is not currently widely used in the UK.

Exposure/everything else

A full secondary survey will not be performed until the patient is in hospital. Prior to transfer, the patient should be packaged appropriately, and covered in such a way as to prevent further heat loss, while allowing clinicians easy access to the patient for en route assessment and treatment. If indicated, and not already given, intravenous antibiotics should be administered.

An alert to the destination hospital prior to arrival will expedite preparation of the receiving clinical team and equipment (including blood products and access to imaging and/or operating room facilities). On arrival at hospital, the pre-hospital physician should provide a succinct handover, in the form of an AT-MIST report (age of patient, time of injury, mechanism of injury, injuries sustained/suspected, signs and symptoms, treatment given).

Future developments

Pre-hospital care is a rapidly evolving medical subspecialty. This is reflected by the ongoing research and guidance that is emerging in this field. A consensus report from a European research collaboration identified the top five research priorities in physician-provided pre-hospital critical care:

• 1
  

  Pre-hospital critical care: staffing, training and effect.

  
  
• 2
  

  Advanced airway management in pre-hospital care: what is best for the patient?

  
  
• 3
  

  Time-critical interventions: what are the time windows for critical care interventions, whether pre- or in-hospital?

  
  
• 4
  

  Pre-hospital ultrasound.

  
  
• 5
  

  Dispatch/activation criteria.

Other areas of particular interest in pre-hospital practice include the delivery of blood products other than just red cells (CRYOSTAT-2 trial), utilisation of REBOA, human factors and crew resource management training and creation of more Standard Operating Procedures (SOPs).

Summary

Pre-hospital trauma care is a developing, challenging and rewarding area of clinical practice. The gradual professionalisation of pre-hospital medicine has brought both recognition and scrutiny to the subspecialty. As advances in knowledge and technology enable more complex interventions to be carried out at the roadside, so we, as responsible clinicians, must be able to rationalise and justify the risk/benefit of everything we do that might delay delivery of the patient to definitive care. There has been increasingly evidence-based standardisation of pre-hospital care. The introduction of SOPs, to facilitate best practice and reduce the clinical decision-making burden, as well as more rigorous audit and governance, to appraise and improve current practice, demonstrate both the value and vulnerability of this area of work. It is paramount that safety and innovation are coexistent in the provision of the right treatment, for the right patient, at the right time.