EDITORIAL The Safety of Orotracheal Intubation In Patients With Suspected Cervical-Spine Injury Critically injured trauma patients may require immediate tracheal intubation to protect the airway, assure the adequacy of ventilation, or initiate controlled hyperventilation for the management of severe head injury. Although physicians generally agree on the indications for tracheal intubation, no consensus exists regarding which technique i& safest in patients with suspected cervicalspine injury. 1 Nasotracheal intubation and orotracheal intubation with manual cervical immobilization are the techniques most frequently recommended; cricothyrotomy is used when these two techniques are contraindicated or unsuccessful. See related article, p 511 Despite years of experience with these techniques, important questions remain unanswered. In patients with an unstable cervical-spine injury, will appropriate use of these techniques prevent spinal cord injury or the exacerbation of an existing spinal cord injury? Is one technique safer than the others? A recent editorial in Annals cautioned that orotracheal intubation with in-line immobilization "has little if any evidence to support its safety. ''2 In this issue of Annals, Rhee and colleagues report the results of a study to determine the safety of orotracheal intubation with "cervical immobilization" in the multiply traumatized patient. Of 237 patients who required tracheal intubation, 21 had a cervical-spine injury; some of these patients also had a concomitant cervical cord injury. Seventeen of the 21 patients with cervical-spine injuries required orotracheal intubation. Although all 17 of these patients had a cervical-spine injury, the exact number who had an unstable cervical-spine injury is less clear. In reviewing the description of cervical injuries, it appears that approximately two thirds of the 17 patients had an unstable cervical-spine injury. This small group constituted the real focus of the study. The authors indicated that orotracheal intubation did not cause cervical cord injury in any of these patients. The retrospective design makes it difficult to know whether manual cervical immobilization or some other technique was used. Another limitation of the retrospective design was the difficulty in determining whether the preintubation neurologic assessment was sufficiently comprehensive to detect a cervical cord injury given the time constraints. This problem is most apparent in patients who arrive in the emergency department with a Glasgow Coma Score of 3 and need immediate airway control. There may not be adequate time to determine whether the patient's neurological impairment is due to severe brain injury alone or a combination of brain and 19:5 May 1990
spinal cord injury. Such examples are found in the second and sixteenth patients cited in their list of patients with cervical-spine injuries. In patient 2, autopsy results would clarify whether the patient had a cervical cord injury; in patient 16 spinal cord injury apparently was not detected until after intubation. Several issues that were not formally addressed in this study deserve comment. The authors state that because of the study design they could not comment on the protective benefit of "cervical immobilization." The terms "inline immobilization," "cervical immobilization," "manual cervical immobilization," and "in-line manual cervical immobilization" are used to indicate that the usual technique of orotracheal intubation is modified to prevent cervical-spine movement. The advanced trauma life support course specifies "in-line manual cervical immobilization. ''3 The term " m a n u a l cervical i m m o b i l i z a t i o n " would seem sufficient without the word "in-line." With the variation in terminology, it is difficult to determine whether immobilization is applied in a uniform manner. If one uses the term "manual cervical immobilization," this implies that an assistant manually applies stabilization during intubation to prevent movement of the cervical-spine. The term "cervical immobilization" could indicate that a device such as a hard collar was used without intervention by an assistant. Cervical movement during intubation may be difficult to detect using only a passive immobilization device. Manual immobilization would seem intuitively more likely to detect cervical movement. In Rhee's study, it is unclear which specific technique was used; this may be a result of the retrospective design. Future studies should indicate the specific technique that is used. The authors indicate that a large prospective study is needed to determine the safety of orotracheal intubation in patients with an unstable cervical-spine injury. However, finding a large number of subjects who meet the selection criteria will prove difficult. Answering the question would require not only a large number of patients with cervical-spine injuries but, more specifically, patients with an unstable cervical-spine injury. Moreover, it would be essential to accurately determine the status of spinal cord function before and after intubation. Because many patients require intubation in the field or immediately after arrival in the ED, determination of the presence and severity of spinal cord injury may not be possible before intubation. One might limit analysis to the presence or absence of spinal cord injury. However, this would require excluding patients who are identified as having acute spinal cord injury prior to intubation. In this latter group, we would be interested in knowing whether intubation exacerbates spinal cord injury. The study reported in this issue should not be inter-
Annals of Emergency Medicine
603/157
EDITORIAL
preted as definitive evidence that orotracheal i n t u b a t i o n is safe i n p a t i e n t s w i t h an u n s t a b l e cervical-spine injury. The l i m i t a t i o n s of a retrospective s t u d y and the small n u m b e r of p a t i e n t s w i t h u n s t a b l e cervical-spine i n j u r y preclude such an interpretation. U n t i l a definitive study is reported, emergency physicians should, as the authors reco m m e n d , select a m e t h o d of airway control based on their o w n skills and experience. However, protection of the cervical spine should be e n s u r e d regardless of w h i c h procedure is used.
158/604
Robert K Knopp, MD, FACEP D e p a r t m e n t of Emergency Medicine Valley Medical Center Fresno, California 1. RosenP, WolfeRE: Therapeuticlegendsof emergencymedicine.J Emerg Med 1989;7:387-389. 2. Joyce SM: Cervical immobilization during orotrachea] intubation in trauma victims (editorial).Ann Emerg Med 1988;17:88. 3. American College of Surgeons Committee on Trauma: Advanced Trauma Life Support Instructor Manual. Chicago, ACS, 1988.
Annals of Emergency Medicine
19:5 May 1990
spinal cord injury. Such examples are found in the second and sixteenth patients cited in their list of patients with cervical-spine injuries. In patient 2, autopsy results would clarify whether the patient had a cervical cord injury; in patient 16 spinal cord injury apparently was not detected until after intubation. Several issues that were not formally addressed in this study deserve comment. The authors state that because of the study design they could not comment on the protective benefit of "cervical immobilization." The terms "inline immobilization," "cervical immobilization," "manual cervical immobilization," and "in-line manual cervical immobilization" are used to indicate that the usual technique of orotracheal intubation is modified to prevent cervical-spine movement. The advanced trauma life support course specifies "in-line manual cervical immobilization. ''3 The term " m a n u a l cervical i m m o b i l i z a t i o n " would seem sufficient without the word "in-line." With the variation in terminology, it is difficult to determine whether immobilization is applied in a uniform manner. If one uses the term "manual cervical immobilization," this implies that an assistant manually applies stabilization during intubation to prevent movement of the cervical-spine. The term "cervical immobilization" could indicate that a device such as a hard collar was used without intervention by an assistant. Cervical movement during intubation may be difficult to detect using only a passive immobilization device. Manual immobilization would seem intuitively more likely to detect cervical movement. In Rhee's study, it is unclear which specific technique was used; this may be a result of the retrospective design. Future studies should indicate the specific technique that is used. The authors indicate that a large prospective study is needed to determine the safety of orotracheal intubation in patients with an unstable cervical-spine injury. However, finding a large number of subjects who meet the selection criteria will prove difficult. Answering the question would require not only a large number of patients with cervical-spine injuries but, more specifically, patients with an unstable cervical-spine injury. Moreover, it would be essential to accurately determine the status of spinal cord function before and after intubation. Because many patients require intubation in the field or immediately after arrival in the ED, determination of the presence and severity of spinal cord injury may not be possible before intubation. One might limit analysis to the presence or absence of spinal cord injury. However, this would require excluding patients who are identified as having acute spinal cord injury prior to intubation. In this latter group, we would be interested in knowing whether intubation exacerbates spinal cord injury. The study reported in this issue should not be inter-
Annals of Emergency Medicine
603/157
EDITORIAL
preted as definitive evidence that orotracheal i n t u b a t i o n is safe i n p a t i e n t s w i t h an u n s t a b l e cervical-spine injury. The l i m i t a t i o n s of a retrospective s t u d y and the small n u m b e r of p a t i e n t s w i t h u n s t a b l e cervical-spine i n j u r y preclude such an interpretation. U n t i l a definitive study is reported, emergency physicians should, as the authors reco m m e n d , select a m e t h o d of airway control based on their o w n skills and experience. However, protection of the cervical spine should be e n s u r e d regardless of w h i c h procedure is used.
158/604
Robert K Knopp, MD, FACEP D e p a r t m e n t of Emergency Medicine Valley Medical Center Fresno, California 1. RosenP, WolfeRE: Therapeuticlegendsof emergencymedicine.J Emerg Med 1989;7:387-389. 2. Joyce SM: Cervical immobilization during orotrachea] intubation in trauma victims (editorial).Ann Emerg Med 1988;17:88. 3. American College of Surgeons Committee on Trauma: Advanced Trauma Life Support Instructor Manual. Chicago, ACS, 1988.
Annals of Emergency Medicine
19:5 May 1990
