Critical Care Challenges; Spinal cord injuries and their management on the intensive care unit

Critical Care Challenges; Spinal cord injuries and their management on the intensive care unit

Simon Hill, ST7 Anaesthetics and ICM at the Royal Surrey County Hospital, Guildford, looks at the challenges of dealing with spinal cord injuries

 

Clinical problem

A 43-year-old male motorcyclist presented to the Emergency Department following a high-speed road traffic collision, where he was ejected from his motorbike at approximately 70 miles per hour. The patient had been attended to by the Helicopter Emergency Medical Service (HEMS) and found to be comatosed with an obstructed airway, obvious right upper limb deformity and an unstable pelvis. The airway was cleared of blood and secretions and secured via rapid sequence induction and intubation with manual inline stabilisation (MILS) followed by cervical spine protection with a rigid collar and three-point immobilisation. Additional management on scene consisted of application of a pelvic binder and splints, as well as bilateral prophylactic thoracostomies.

Transfer to ED was uneventful and the patient was assessed by the trauma team, according to trauma unit protocols. Primary survey was performed followed by a CT traumagram, which revealed several bony and soft tissue injuries, including the suspected pelvic fracture but, of note, no intracranial pathology or spine injuries were noted. No acute surgical intervention was deemed necessary immediately and the patient was transferred to the intensive therapy unit (ITU) for a period of stabilisation and monitoring. The pelvic fracture was thought to require surgical fixation but this was deferred to a later date.

 

Critical care management

The patient was initially managed with a hard collar, log rolling and sedation. Due to the high velocity mechanism of injury with concurrent bony injuries, a repeat CT head was performed after a period of approximately two hours to exclude evolving evidence of raised intracranial pressure. This was also reported as normal.

A period of observation on ITU occurred over the next 72 hours, during which time the patient remained intubated and sedated while awaiting internal fixation of his “open book” pelvic fracture. During this time, sedation holds were performed daily but, as the patient was unable to follow commands, the cervical spine was deemed not suitable to be “cleared clinically” as clinical examination to exclude ligamentous injury and underlying spinal cord injury (SCI) was not possible.

The hard collar was changed to a Miami J collar under the advice of the orthopaedic team and the pelvic binder was released, but the patient remained for log rolls until pelvic fixation. Due to lack of availability of MRI facilities and ongoing reduced GCS, it was recommended that fluoroscopic imaging under anaesthesia be performed to assess C-Spine ligament stability prior to his pelvic surgery.

Plans for surgery were abandoned after transfer to theatre due to significant transient hypoxaemia and haemodynamic instability, which was, in turn, diagnosed as bilateral pulmonary emboli on CT pulmonary angiogram. Subsequently the patient was heparinised, although not thrombolysed due to the risk of catastrophic haemorrhage from his ongoing injuries. An inferior vena cava (IVC) filter was inserted to prevent further thromboembolic events.

The insertion of the IVC filtered combined with a seven-day wait for pelvic fracture internal fixation and persistently depressed GCS during repeated sedation holds resulted in a prolonged period without C-spine clearance. The decision was made that a trachestomy formation to aid weaning from sedation and ventilation would be required, however this could be difficult in the context of an uncleared C-Spine and the potential risk of Spinal Cord Injury Without Radiological Abnormality (SCIWORA), complicated further by the risks associated with the heparinisation.

Spinal neurosurgical opinion was sought and it was recommended that MRI be performed, but due to the new metallic IVC filter insertion this was deemed not to be feasible. Therefore, after multidisciplinary discussion, a decision was taken to maintain Miami J collar immobilisation until a return to theatre for a fluoroscopic imaging, pelvic fixation and tracheostomy formation.

 

Discussion

SCI is a relatively uncommon injury occurring in approximately 13 to 54 cases per million of the population in the western world (UK and USA) and the number of people in the UK living with paralysis is thought to be around 40,000 cases.[1]

The majority of SCI in the UK result from falls, road traffic accidents or sport-related injury. Male to female predisposition is 4:1 with a mean age of 33 years old. SCI can be subdivided into primary (as a direct consequence of the mechanical injury) and secondary injuries which occur after the initial trauma and are potentially avoidable [3].

Management of trauma patients with suspected C-Spine injuries has generally been dictated in recent years by the principles of the American College of Surgeons Advanced Trauma Life Support (ATLS), which teaches airway and C-Spine protection with hard collar immobilisation to present secondary SCI [4].

The level of consciousness, distracting injuries and mechanism of injury dictate whether clinical screening tools for SCI or Cervical Spine Injury (CSI) like the Canadian C-Spine rules, or the NEXUS rules, can be used, or whether imaging is required [5].

Trauma patients with suppressed GCS rendering clinical assessment challenging if not impossible can present a management conundrum on the ITU. Due to the lack of clarity that exists regarding C-Spine clearance in this situation, patients can, in some cases, end up undergoing significant periods of ventilation with full C-Spine immobilisation. This, in turn, leads to risks such as pressure sores, difficult airway assess, difficult central venous access and difficult mouth care, not to mention raised intracranial pressure and risk of thromboembolism [6].

The evidence for CSI in the unconscious patient is based around radiological imaging with:

  1. Plain cervical spine radiographs – anteroposterior, lateral and open mouth.
  2. Multislice CT cervical spine with 3D saggital and coronal reconstruction.
  3. Dynamic fluoroscopy – for ligamentous instability.
  4. MRI – for soft tissue/ligamentous damage.

A comprehensive review in 2004 by Morris et al looked at clearing the C-Spine in an unconscious trauma patient and the effectiveness of each of the aforementioned imaging modalities. This review essentially concludes that in the polytrauma patient with a depressed level of consciousness for a period of >48-72hrs, three cervical radiographs along with an expertly interpreted high-resolution CT scan with saggital reconstruction will exclude 99.5 per cent of cervical spine injury.

The reticence of some clinicians to expose their patients to the risk, however small, of the potentially severe complications of CSI, namely tetraplegia, is understandable. However, given the low likelihood of such an eventuality compared to the significant and well-documented morbidity and mortality burden related to prolonged immobilisation may suggest that a more pragmatic risk-benefit approach should be taken.

Many trauma units and major trauma centres in the UK now take such a pragmatic approach. Removal of rigid collars and cessation of spinal precautions in patients who are intubated and sedated on the ITU and who cannot be clinically cleared of C-Spine injury, but who are radiologically cleared on CT scanning is becoming increasingly common practice.

 

Lessons Learnt

  • SCI/CSI are relatively uncommon injuries, but the serious potential consequences of missed SCI/CSI means that clinicians may be cautious in assessing the risk of prolonged spinal immobilisation.
  • UK practice is changing to reflect the strong evidence base for complications resulting from prolonged immobilisation.
  • Many UK units now remove rigid collars and cease full immobilisation in ventilated patients on the ITU when patients are “radiologically cleared” by CT scanning reported by appropriately trained staff.

 

References

  1. https://www.nscisc.uab.edu/Public/Facts%202016.pdf
  2. http://www.apparelyzed.com/statistics.html
  3. Bonner et Smith (2013) Initial management of acute spinal cord injury Contin Educ Anaesth Crit Care Pain (2013) 13 (6): 224-231.
  4. American College of Surgeons Committee on Trauma. ATLS–9th Edition 2012, American College of Surgeons, Chicago
  5. Cowie et Andrews (2013)The Unstable Cervical Spine ATOTW 292 http://www.frca.co.uk/Documents/ 292%20The%20Unstable%20Cervical%20Spine.pdf
  6. Harrison et Cairns (2008) Clearing the cervical spine in the unconscious patient Contin Educ Anaesth Crit Care Pain (2008) 8 (4): 117-120.
  7. Morris et McCoy (2004) ‘Clearing the cervical spine in unconscious polytrauma victims, balancing risks
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