Selective Immobilization: Current Research and Practice
EMS providers make clinical decisions regarding treatments they employ every day, and cervical spine immobilization is no different. Not every 20-year-old who twists his ankle falling on the stairs comes to the ED on a board, nor does every 65-year-old who has chest pain after a minor fender-bender. Clinical decision guidelines or protocols are the foundation of care in the prehospital setting. Several EMS systems are currently performing selective spinal immobilization. Where did the protocols that are being followed come from, and how have they continued to develop?
As with most other prehospital protocols, the guidelines for selective spinal immobilization are developed from emergency department and trauma surgery practice. In the prehospital arena, EMS providers must decide whether or not a patient should be immobilized using a long spineboard, cervical collar and cervical immobilization devices to prevent exacerbation of existing injuries during transport. For an ED physician, the question becomes whether or not to obtain x-rays of the cervical spine to evaluate for fracture or other unstable injury. For both, the question is whether the risks and costs of treatments and investigation outweigh the benefits of not filming or immobilizing and the inherent risk of missing a cervical spine fracture.
In the ED, the treatment risks include the unknown effects of doses of ionizing radiation, as well as prolonged stays in the ED and significantly increased costs. For EMS, the risks include aspiration, discomfort, injuries from bumpy rides on hard boards and anxiety from loss of physical control.
Over the last five years, ED treatment of patients with presumed cervical spine injuries has changed after completion of two different scientific studies of cervical spine x-ray procedures. Prior to completion of these studies, patient evaluation was done clinically by individual practitioners with no guidelines. Each provider made his own rules for ordering x-rays, given his length of time in practice, relationship with the patient, and patient history and physical exam. Two studies changed that. In July 2000, National Emergency X-Radiography Utilization Study (NEXUS) Group published the results of its validation study of clinical guidelines, and in October 2003, The Canadian C-Spine Rule for Radiography in Alert and Stable Trauma Patients was published.
NEXUS and the Canadian C-Spine Studies
The NEXUS study, highlighted in the accompanying article on page 99, was conducted at 21 university centers with patients whose emergency physicians believed needed to have x-rays due to concern for potential cervical spine injury, regardless of mechanism, injury pattern or mental status. By collecting a wide array of information about each patient who received x-rays and then reviewing the x-ray results, the authors were able to establish a set of clinical criteria that could be used as a guide for ordering x-rays in high-risk patients. The guidelines were then validated clinically in 34,069 prospective cases.
The NEXUS guidelines showed remarkable sensitivity in picking up cervical spine injuries in all patients who presented to the emergency department. Of the 818 cervical spine injuries diagnosed in the study population, all but eight would have been discovered using the clinical decision rule. This is a missed fracture rate of less than 1%. There were no adverse outcomes among the study population.
The Canadian cervical spine evaluation guideline was developed similarly at 10 emergency departments across Canada on 8,924 patients. The patient population studied was slightly different, with all patients enrolled having trauma to the head or neck, and all with a Glasgow Coma Score of 15. These guidelines highlighted concerning mechanisms, or head and neck trauma, as well as mechanisms that were low risk. This rule had 100% sensitivity for cervical spine fracture. No fractures were missed, but not everyone was filmed.
The two guidelines were compared in December 2003 to help determine which was more accurate at identifying fractures and would result in fewer negative x-rays. There are a number of confounders that make it difficult to compare the studies—notably, using a very different patient population as subjects. There are a number of factors from this comparison article that we should probably be concerned with in a prehospital setting:
• Injury above the clavicles
If a patient has sustained a serious injury that the Canadian study identifies as an axial loading injury similar to a diving accident, a motor vehicle crash at over 60 miles per hour, or a fall from more than three feet, the first determining factor for whether or not the patient should receive radiographs is an injury above the clavicles.
• Distracting injury
There are a number of studies that attempt to create a universally derived definition of distracting injury. Clearly, this is a very patient-specific definition and cannot be defined beyond a set of minimum guidelines.
• Age >65
These patients were previously determined to be at greater risk for injury and have a higher rate of cervical fracture than younger patients with similar mechanisms of injury. The Canadian cervical spine investigative group found that patients at the extremes of age are much more likely to suffer cervical spine fractures, particularly of the high cervical spine. This is probably the most important guideline that we should take from the cervical spine immobilization group. Realize that age 65 is taken randomly, with the expectation that as patients age, they will have altered bone structure and pain reception.
In 2001, the Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons published Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries, which reviews the literature, but does not issue treatment guidelines or standards.
The document recommends that “all trauma patients with a cervical spinal column injury or with a mechanism of injury having the potential to cause cervical spinal injury, should be immobilized at the scene and during transport using one of several available methods.” This is a large group of patients.
National educational courses for prehospital providers have differing flowcharts for spinal immobilization and teach slightly different techniques. The Basic Trauma Life Support guideline has a default of immobilization concerning mechanism. PreHospital Trauma Life Support has no default for automatic immobilization and recommends management based upon physical exam, but the flowchart contains the caveat, “Use clinical judgment. If in doubt, immobilize.” Norman McSwain, MD, a PHTLS program author, says that it teaches EMTs to think and make judgments based on knowledge. The guideline for immobilization is part of that educational philosophy. This caveat is important and allows a provider’s judgment to provide an independent basis for care.
In the National Association of EMS Physicians’ position paper on Indications for Spinal Immobilization, altered mental status and evidence of intoxication are the first two criteria for immobilization following blunt trauma. Mental status, appropriateness and alertness are all components for determining reliability. An interesting part of BTLS and PHTLS is the location of reliability assessment in their algorithms. A careful review demonstrates that the physical exam precedes assessment of the patient’s reliability. In clinical practice, the patient’s reliability would be central to the findings on exam and would be continually re-evaluated.
Existing Selective Spinal Immobilization Programs
What about agencies that are already employing selective spinal immobilization? Those with the greatest experience are in the state of Maine. Initially employed in the early 1990s, the selective spinal immobilization program in Maine has undergone continual development, as well as continuous quality assurance, since its inception. The protocol was most recently updated in 2002. During the time Maine has employed selective spinal immobilization, there have been no reports of patients sustaining additional injury as a result of selective spinal immobilization guidelines being employed in the field.
Researchers in Maine examined results from one year. Of more than 200,000 EMS encounters, 36,719 patients were transported from the scene of trauma-related mechanisms. Hospital discharge data identified 159 fractures, or an incidence of 0.4% of traumatic patient encounters. Locations of the fractures were evenly distributed: 30% were cervical, 28% were thoracic and the remainder were lumbar. Of the 159 fractures, 28, or 17.6%, were not immobilized by EMS for transport to the emergency department. Only one patient with an unstable fracture was transported without immobilization. She was an elderly woman who had persisting back pain for a week after falling from her couch and was found to have an unstable thoracic fracture. Interestingly, close review of the trip sheets demonstrated that 19 of the 28 fractures, or 68%, were in patients older than 65. The study’s lead investigator believes that some of these patients may not have been immobilized by EMS because the provider felt it would be more traumatic for the patient. Clearly, this needs additional research, both to discover etiology of the protocol deviation and to continue to review whether there has been any harm to patients.
Retrospective quality assurance, continuous quality improvement and follow-up are important parts of any new protocol. From this study, we know that the selective spinal immobilization program in Maine is allowing nonimmobilized patients to be transported to the hospital with fractures, although EMS personnel have documented that they applied the protocol. Investigators, medical directors and EMS management in Maine must now decide if the providers are poorly applying an appropriate protocol, whether the protocol should be rewritten, or if the providers’ education needs to be improved. Particularly, will Maine decide if the protocol should apply to patients over age 65? These are difficult questions, but they need to be asked any time we discover protocol deviations. The contributions of this work are extremely important to selective spinal immobilization programs everywhere, and, as this program, with its remarkable oversight continues, investigators will continue to raise difficult questions and improve the level of care for all patients.
One question that remains unanswered is whether or not cervical spine immobilization makes a difference in patient outcomes. Since trauma education of ambulance personnel began, we have heard that cervical spine immobilization is paramount to trauma care. On the other hand, in the awake and alert patient, we have no data to suggest whether it is beneficial or not. A number of authors claim that no negative outcomes have been reported as a result of patients not being immobilized. In fact, some authors believe that it is extremely rare, if not implausible, that a patient who arrives into EMS care without any neurological deficits will sustain neurological deficit as a result of their care by EMS.
Due to the litigious nature of the U.S. medical environment and the difficulty in changing standards of care, it is extremely unlikely that we will see a randomized controlled study of cervical spinal immobilization against normal immobilization for all patients in the field. At the same time, however, the only study that has been performed to do this was a matched patient control study, which, while having many imperfections, did not demonstrate any worse outcome for patients who did not receive cervical spinal immobilization.
What can we take from all of these studies? First, NEXUS shows us that mechanisms should serve as a guide for care and evaluation, but not a firm rule for treatment in a prehospital environment. The Canadian c-spine rules teach that mechanism associated with injuries above the clavicles puts a patient at risk for cervical spine fracture. Information from Maine, combined with the Canadian rules, suggests that patients who are >65 years old are at greater risk for missed cervical spine fractures, yet NEXUS found no association between age and missed injury. As protocols develop, this result may drive systems in two separate ways: Some services may elect to immobilize older patients, while others may address EMS physical exam skills of the older patients through increased education. Either is clearly appropriate and can be supported by evidence.
Not everyone with blunt trauma needs to be on a backboard or in a collar. EMS medical direction and educators must provide field personnel with the tools to identify those persons who need immobilization because they are at high risk of injury. It is important for EMS providers to remember that there is a big difference between immobilization when indicated and attempting to “clear” the c-spine in the field. EMTs should do the former, but not the latter. Clearing the c-spine is a physician responsibility in the ED. While appearing to be a minor semantic difference, this is a major difference in medical thought and responsibility. Prehospital providers are not trained to clear or rule out disease processes.
Selective spinal immobilization is part of the important clinical judgment and decision-making that EMS providers do every day. Research must continue to drive the development and revision of protocols that assist caregivers and improve care for patients. Adherence to protocols, good quality assurance mechanisms and aggressive research will allow EMS to offer evidence based on continually developing care to our patients.
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