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Objective: Immediate rescue breathing, or cardiopulmonary resuscitation, may be necessary for the cervical spine-injured football player without removal of the helmet. The purpose of our study was to compare 2 pocket-mask insertion techniques with a face-mask rotation technique to determine which allowed the quickest initiation of rescue breathing with the least cervical spine motion.
Design and Setting: In a biomechanics laboratory, 3 airway-preparation techniques were tested: chin-insertion technique (pocket mask inserted between the chin and face mask), eye-hole-insertion technique (pocket mask inserted through the face mask eye hole), and screwdriver technique (side loop straps removed using manual screwdriver followed by mask rotation).
Subjects: One athletic trainer team and 12 National Collegiate Athletic Association Division III football players.
Measurements: Time to initiate rescue breathing and induced helmet motion.
Results: Both pocket-mask techniques allowed quicker initiation of rescue breathing. Cervical spine anterior-posterior displacement was greater for the chin technique than for the screwdriver or eye-hole techniques. Lateral translation was greater for the screwdriver technique than for either pocket-mask technique. Peak displacement from initial cervical spine position was greater for the chin technique than for the eye-hole technique.
Conclusions: Both pocket-mask techniques allowed quicker initiation of rescue breathing than did rotation of the face mask via loop strap screw removal. The eye-hole insertion technique was faster and produced less cervical spine motion than the other 2 techniques. Each technique produced significantly smaller amounts of cervical spine displacement than that caused by cutting face-mask loop straps as reported earlier. We suggest a protocol for field management of cervical spine injuries in football players.
The optimal protocol for managing cervical spine injuries in helmet sports such as football, ice hockey, and lacrosse has been studied with renewed interest since 19891–4. Although writings on this subject began as early as the 1970s,5 only recently have investigators attempted to quantify the impact of various management techniques in an effort to develop protocols that offer greater assurance of being safe and effective.4,6
Cervical spine injuries, especially those accompanied by respiratory or cardiac arrest, pose one of the most serious challenges a sports medicine clinician can face. Appropriate on-field management consistent with protocols that have been demonstrated to be safe and effective is essential. Many opinions exist regarding the best way to expose the airway of a cervical spine-injured football player.1–3,7–11 Endotracheal intubation performed by a health care provider skilled in this technique is the gold standard for managing the airway of any athlete in respiratory arrest. Because paramedics trained in intubation are often not present during the first critical minutes after the onset of cervical spine injury-induced respiratory arrest, athletic trainers are forced to use other methods for managing the airways of athletes in their care. Fortunately, simply opening the airway via the modified jaw thrust is often enough to restore breathing in a spine-injured athlete. When respiratory arrest presents in the presence of a patent airway, however, the Occupational Safety and Health Administration (OSHA) requires health care providers to use a barrier device such as a pocket mask or bag-valve mask during rescue breathing.12 This factor has generally been ignored in previously published protocols, even though it has the potential to alter the way this injury is managed on the field. The purpose of our study was to compare 3 airway-preparation techniques to determine which allows the quickest initiation of rescue breathing with the least amount of extraneous cervical spine motion.
Previous work4 in this area suggests that the insertion of a pocket mask with a one-way valve under the face mask and over the mouth and nose allows quicker initiation of rescue breathing with less cervical spine motion than face-mask rotation with a cutting tool like the Trainer's Angel (Trainer's Angel, Riverside, CA). The pocket-mask insertion method studied by Ray et al4 involved sliding the pocket mask between the chin and the lowest part of the face mask and positioning it over the mouth and nose. The one-way valve was then inserted through the bars of the face mask. The efficacy of the pocket-mask insertion technique was demonstrated in the pilot study for that investigation. The authors showed that it was possible to create an effective seal and adequately ventilate the lungs of a cardiopulmonary resuscitation (CPR) manikin wearing a football helmet using the pocket-mask insertion technique in combination with the modified jaw thrust. Another portal of entry, not studied in that investigation, involves inserting the pocket mask through the eye hole of the face mask. We pose the following questions based on this research: (1) Does the eye-hole insertion method allow for quicker initiation of rescue breathing than either the chin-insertion method or rotation of the face mask via screw removal? (2) Does the eye-hole insertion method induce less cervical spine motion than the chin-insertion method or rotation of the face mask via screw removal?
This experiment was carried out in the Biomechanics Laboratory at Hope College. Two senior-level athletic training students (M.A.F. and W.H.) performed the techniques as an athletic trainer team in the same manner on each football player participating in the study. The athletic trainer team practiced several times per week for approximately 10 weeks before data collection in order to ensure uniformity in the performance of the techniques and to eliminate learning as a possible confounding influence. Each experimental session lasted approximately 30 minutes.
Twelve National Collegiate Athletic Association Division III football players volunteered to participate (Table (Table1).1). All participants had a head size appropriate to fit a large-shell Bike Air Power (Bike Athletic Co, Knoxville, TN) football helmet. All participants provided informed consent in compliance with the college's institutional review board, which approved the study.
Helmet motion was measured using an optoelectronic motion analysis system (Optotrak 3020, Northern Digital Inc, Waterloo, Ontario, Canada). The Optotrak measures motion by tracking infrared emitting diodes (IREDs) in 3 dimensions and is accurate to 0.75 mm (for displacements) and 0.1° (for rotations).
All participants wore a helmet with an aluminum boom attached to the crown. The boom terminated in a T with 4 IREDs defining a horizontal and vertical axis (Figure (Figure1).1). The T was oriented perpendicular to the cervical spine. The distance from the IRED on the horizontal axis to the center of the ear hole was measured so that the measured boom motion could be used to estimate (assuming the head and helmet move as a rigid body) the net rotation and translations at the cervical spine necessary for the measured helmet motion (Figure (Figure2).2). (Note: Cervical spine motion was inferred from helmet motion. Tissue compliance between the scalp and skull may result in imperfect cervical spine motion estimates, but the problems associated with direct measurement in real time on living participants wearing football equipment made this a safe method for estimating cervical spine motion. Future references in this paper to cervical spine motion are inferred from helmet motion.) Data were collected at 50 Hz for 40 seconds. The time required to complete each technique was determined through videotape analysis.
Baseline measures, including signal noise, motion from breathing, applying and maintaining in-line stabilization, and rotating the face mask have already been shown to cause less cervical spine motion than airway-preparation techniques.4 Although the gold standard in the management of cervical spine injuries is no neck movement at all, even patient breathing causes some movement.4 Baseline measures, including the application of the modified jaw thrust, have been demonstrated to cause 12 to 58 times less cervical spine motion than face-mask rotation using a Trainer's Angel.4 Because of this, baseline motions were not recorded in this study.
The experimental helmet was fit to each participant according to the manufacturer's specifications. The helmet was fit with a lineman-style face mask with a center bar (JNOP, Schutt Manufacturing, Litchfield, IL). This face-mask style was used because the center bar was presumed to pose additional challenge to the athletic trainer team in inserting the pocket mask. We acknowledge that the results of our study could be different for other facemask styles. The helmet was affixed with a 4-point, hard-shelled chin strap. Participants wore shoulder pads and a jersey while lying supine on a carpeted floor. Three airway-preparation techniques were conducted on each participant: (1) insertion of a pocket mask (Laerdal Medical Corp, Armonk, NY) through the space between the chin and the lowest part of the face mask, (2) insertion of a pocket mask through the eye hole of the face mask, and (3) rotation of the face mask with a manual screwdriver. The manual screwdriver technique involved removal of the screws in the face-mask side loop-straps and rotating the face mask out of the way before placing a pocket mask over the participant's mouth and nose. Screws were replaced after every fourth trial and were tightened to a standard torque of 3 inch-pounds using a torque screw driver (Apco Mossberg Co, Attleboro, MA).
Before the initiation of each technique, one athletic trainer (W.H.) applied in-line stabilization. Another athletic trainer (M.A.F.) performed the technique when prompted by a light stimulus. Before beginning the study, we established a randomized order for the treatments and replicated this order across all participants.
Data were analyzed using MATLAB (The MathWorks Inc, Natick, MA) and SPSSX (SPSS Inc, Chicago, IL). Cervical spine motion was measured in 4 ways: (1) anterior-posterior displacement, (2) lateral displacement, (3) rotation, and (4) peak displacement from initial spine location.
We analyzed participant and athletic trainer team learning from trial 1 to trial 2 using t tests for each method. Athletic trainer team learning over the course of the study was evaluated by comparing the time and motion parameters of the first 6 participants with those of the last 6 participants using t tests. Time and cervical spine motion differences among the 3 methods were analyzed using a one-way analysis of variance with a post hoc least-squares difference test. The cervical spine motion data for one participant were corrupted and were not included in the analyses.
Significant differences were observed in the time required to perform the techniques. Exposing the airway by rotating the face mask with a manual screwdriver took significantly more time than either of the pocket-mask insertion techniques (Table (Table2).2). It is important to point out that each technique introduced some cervical spine movement. The pocket-mask insertion technique using the eye hole as an entry portal produced the smallest amount of extraneous cervical spine motion; however, there was no statistical difference in the amount of cervical spine rotation among the 3 techniques. Anterior-posterior translation (movement of the cervical spine in the sagittal plane) was significantly greater for the pocket-mask insertion technique using the chin space as the entry portal than for the other 2 techniques. Lateral translation (movement of the cervical spine in the frontal plane) was greater for the manual screwdriver than for either of the 2 pocket-mask insertion techniques. Peak displacement (the greatest distance the cervical spine moved from the beginning to the end of the maneuver, regardless of the direction of the movement) was greater for the chin insertion method than for the eye-hole insertion method.
The effect of learning by the athletic trainer team and the participants was evaluated by comparing the time and motion means for trial 1 and trial 2. Trial 2 dependent variable means were lower than those for trial 1 in every case. Five of 15 differences were statistically significant (t11 > 2.80, P < .02 for each variable). In subsequent data analyses, we used only trial 1 for the following 3 reasons: (1) trial 1 data were more conservative in every case, (2) there is some evidence to support the hypothesis that athletic trainer team and participant learning occurred from trial 1 to trial 2, and (3) health care professionals using these techniques under actual field conditions must perform them in an optimal manner on their first attempt in order to maximize the outcome for the patient.
Because the results could also be skewed by improvements in athletic trainer team technique over the course of the study, we compared the means for each variable for each technique for the first 6 participants with those of the second 6 participants using t tests. No differences were observed, indicating that the athletic trainer team applied the techniques in a similar fashion for both the first and second half of the participants.
Although the incidence of cervical spine injuries in football is low,13 the potential for life-threatening complications arising from such injuries makes their management one of the most important skills that sports medicine clinicians must have. The incidence of secondary injury to the spinal cord caused by poor prehospital treatment in the field is high: 10% of patients in one study14 and 25% in another.15 Because the football helmet with its face mask presents obstacles not normally seen in victims of other types of accidents, the need for consensus protocols for cervical spine injury management in football is critical. Recently an interassociation task force comprising members from 26 emergency and sports medicine organizations promulgated guidelines for appropriate care of the spine-injured athlete.16 This consensus statement has helped decrease the disparity of opinions among various health care professionals—particularly certified athletic trainers,9 emergency medical technicians,2 and physicians17–19—regarding helmet removal. The need to leave the helmet in place in all but the most unusual situations is, we hope, being recognized and resolved. Recent policy statements by the National Athletic Trainers' Association and the American College of Sports Medicine call for leaving the helmet on until cervical spine fracture or dislocation can be ruled out by x-ray in the hospital.6 Recent researchers3,20 have confirmed what Schneider5 suspected nearly 30 years ago, that helmet removal causes significant cervical lordosis and is the single greatest cause of extraneous cervical spine motion after serious neck injury.21,22
The need for absolute spinal immobilization23 in the context of the athlete with the still-affixed football helmet is the area of greatest consensus among the health care practitioners who typically provide care for football players with cervical spine injuries.24 The issue of how to most effectively expose the airway in a timely manner remains controversial.1,2,4,6,8–11,25 The modern football helmet is equipped with a face mask affixed by 4 loop straps screwed to the helmet. These loop straps have rendered bolt cutters—and the significant cervical rebound associated with their use26—obsolete for face-mask removal. Several authors8,9,11 have offered their opinions regarding the best way to remove the face mask and thereby expose the airway, and more is now known about the effects of these techniques on cervical spine motion than through the mid 1990s.27 The OSHA requirement that health care providers use a barrier device such as a pocket mask or a bag-valve mask during rescue breathing further complicates the issue of safe airway management in spine-injured athletes and makes it essential that this element is incorporated into standard airway-management protocols.12,28
In a previous study,4 we compared, in a controlled setting, the effects of 3 common and 1 new method to quantify the time required and the motion induced with the most common methods for airway exposure. We discovered that opening the airway by using a modified jaw thrust after inserting a pocket mask with a one-way valve through the space between the chin and the still-affixed face mask allowed quicker initiation of rescue breathing than face-mask rotation using a manual or power screwdriver or a Trainer's Angel cutting device. The Trainer's Angel was associated with significantly greater cervical spine motion than the other 3 techniques. As do all cutting tools, it leaves an anterior remnant of the face mask loop strap that the face mask bar must pass over before it can be rotated. This induces an unacceptable amount of mechanical rebound, resulting in cervical spine motions that can approach 10 mm, nearly 25% of the width of the vertebral foramen at its widest point. This is not meant to suggest that cutting the loop straps should never be attempted. Cases will exist where this method is the only practical alternative for face-mask removal: when the loop strap screws are rusted or stripped, for example. Data from our previous study4 do suggest, however, that face-mask removal after loop-strap cutting is a less benign treatment option than may be widely assumed.
The pocket-mask insertion technique using the eye hole shows some promise of being a safe and effective method for managing the airway of a cervical spine-injured football player. Previous work4 has demonstrated the practicality and efficacy of ventilating a patient wearing a football helmet using the pocket-mask insertion technique. Both pocket-mask insertion techniques (chin and eye hole) offer speed advantages over face-mask rotation via screw removal. The 18-second difference could potentially allow for slightly more than 3 cycles of rescue breathing. For an injury in which every second counts, this time savings could be important. The cervical spine motion induced when the pocket mask is inserted through the eye hole is less than that for any other method studied in a controlled setting. Indeed, when compared with methods that employ a cutting device to sever the side face-mask loop-straps, the eye-hole insertion method reduces motion by a factor of 4 to 5.4
The question of which technique-induced cervical spine movement is most clinically significant is difficult to answer. The answer probably depends on the type, location, and severity of the cervical lesion. We reported 4 types of motion (rotation, anterior-posterior displacement, lateral displacement, and peak displacement) in an effort to provide clinicians with as complete a picture as possible for how the cervical spine is affected during airway-preparation maneuvers. Because the gold standard for management of cervical spine injury is complete immobilization, we cautiously recommend that clinicians take all necessary steps to minimize peak displacement (since this represents the maximum distance the spine travels during the airway-preparation maneuvers) while recognizing that other extraneous motions can also result in poor outcomes.
Although the results of our study confirm the utility of the pocket-mask insertion techniques in terms of both the time they require and the motion they induce, the question of which entry portal is optimal poses a clinical decision that can probably only be made on the field. The evidence to support the commonsense notion that athletes with “bigger” faces have less room in which to insert and position the pocket mask prior to jaw thrust and rescue breathing is inconsistent. Our previous study demonstrated moderate to high correlations (−.67 to −.78) between chin-to-face-mask distance and cervical spine motion induced during the chin-insertion method. Correlations for these measures were much weaker in this study (−.08 to −.34). Similarly, the correlation between nose-to-face-mask distance and cervical spine motion using the eye-hole insertion method ranged from −.26 to −.54. The correlation between the time required to complete the eye-hole insertion method and the nose-to-face-mask distance in this study was −.65. Because no clear pattern has been demonstrated across both studies, we recommend that clinicians choosing to use one of the pocket-mask insertion techniques make a rapid assessment of the 2 entry portal sizes and choose the largest through which to insert the pocket mask. Since a pocket mask with the tube folded for insertion under the face mask is approximately 5.08 cm (2 in) tall, a face mask portal of at least 5.08 cm would, in theory, provide the least resistance to proper insertion of the pocket mask.
Nothing in our findings should be construed as suggesting that either of the pocket-mask insertion techniques are “stand-alone” therapies for cervical spine-injured football players in respiratory arrest. Rapid intubation is still the gold standard. Because intubation presumably requires the rotation of the face mask and most injured athletes will not have ready access to intubation immediately after on-field assessment of their airway patency, we recommend use of one of the pocket-mask insertion techniques as a preliminary measure only. The rapid employment of this technique will allow the athlete to receive life-saving rescue breathing from one health care provider while another rescuer carefully removes the screws that attach the face mask to the helmet. When paramedics arrive on the scene, the athlete will be ready for immediate intubation. It is important to note that neither the screwdriver nor the screws failed throughout this study. Screwdriver failure (even with new hardware) is a problem associated with the screwdriver technique.
The question of which is more important, to minimize the time or minimize the induced cervical spine motion during airway preparation, is an important but difficult question to answer. Unfortunately, our study was not designed to answer this question, nor should the data be used for this purpose. To minimize the potential damage due to the lack of oxygen, the athletic trainer's goal should be to minimize the time to initiation of rescue breathing. On the other hand, in the presence of an unknown cervical spine injury, the athletic trainer has the confounding goal to minimize cervical spine motion while implementing the chosen airway-preparation technique. Therefore, the study conclusions regarding the fastest airway-preparation technique that introduces the smallest cervical spine motion should be used by the athletic trainer to make the best on-site decision possible.
A discussion of the effect of practice on learning these techniques is important. We demonstrated in our previous work that practice does decrease the time it takes to perform these techniques.4 This finding has been confirmed in other studies as well.29 Practice also tends to decrease the amount of extraneous motion induced at the cervical spine, regardless of the technique being used. In this study, we found improvements in time and motion variables from one trial to another within participants but no differences between participants from the beginning to the end of the study. The improvement within participants was probably due to small adjustments in the athletic trainer team's technique from one trial to the next based on individual participant characteristics, such as face size and shape. Although no long-term learning was demonstrated in this study, the fact that the athletic trainer team had practiced the techniques for approximately 20 hours over the course of the 10 weeks before the study suggests that these skills must be practiced in order to be mastered. Anecdotally, we observed significant improvement in our technique from the beginning to the end of the 10-week practice period. Although the effect of practice on the learning of these skills was not the primary focus of either this or the previous study, our findings suggest that clinicians must devote more time to practicing these skills than they are currently devoting.
An important limitation of this study regarding variability needs to be discussed. The design of this study was a single athletic trainer team performing the airway-preparation techniques on a group of football players. Thus, the design used here included only the variability of the characteristics of the football player on the study variables (time and motion). Another source of variability affecting the study parameters was the variability across athletic trainer teams, which we did not address. Therefore, a future study design should include the effect of athletic trainer team variability on the study measures.
An additional limitation concerns the net rotations and translations reported here as cervical spine motion. We have not directly measured spine motion, which would require x-ray methods or the attachment of markers rigidly to the vertebrae. As already mentioned in the Methods section, the measured boom motion with rigid body mechanics was used to estimate the net rotation and translations at the cervical spine necessary for the measured helmet motion to occur. Future researchers should consider the error in estimating net rotations and translations about the cervical spine based on tracking targets affixed to the helmet.
We also recommend the following areas for additional study:
Under ideal conditions, the pocket-mask insertion technique using either the chin or eye hole as an entry portal allows for quicker initiation of rescue breathing than rotation of the face mask using a manual screwdriver. Although not always statistically significant, the eye-hole pocket-mask insertion technique consistently produced less extraneous cervical spine motion than the other 2 techniques. All 3 methods induced less cervical spine motion than techniques that involved cutting the face-mask loop-straps, as reported in other investigations.
Therefore, when the athlete is breathing, do not attempt to rotate the face mask, because all face-mask rotation methods result in cervical spine motion. The data from this study and our previous work in this area4 support the fact that face-mask rotation techniques can induce significant cervical spine motion, even under controlled laboratory conditions.
If the athlete is not breathing, log roll the player into position and open the airway using the modified jaw thrust. If the athlete does not begin breathing after the airway has been opened, determine which entry portal through the face mask offers the greatest access—the chin or the eye hole—and perform the pocket-mask insertion technique and begin rescue breathing or CPR.
We gratefully acknowledge Dr John Shaghnessey, from Hope College, for his assistance with the statistical analysis.