The study conducted by Arnaud Robitaille et al is aimed at comparing cervical spine movement during GlideScope videolaryngoscopy (GVL) and direct laryngoscopy (DL) by means of continuous cinefluoroscopy. The authors argue that videolaryngoscopy can bring the advantages of intubation and direct lanyngoscopy especially over flexible bronchoscope because it gives an indirect view of a patient’s glottis and this can diminish the movement of cervical spine (Robitaille et al, 2008, p 936). They hypothesize that GVL will produce less movement of C-spine than DL. The ultimate goal of this study is to determine which of these methods can be more suitable for the patients with C-spine injury.
This research was conducted on twenty patients who did not have any pathology of C-spine. GVL and DL were performed at every patient after general anesthesia and in random order. With the help of continuous cinefluoroscopy the researchers measured the movement of C-spine at different stages, namely: 1)before any manipulation of the airways; 2) glottis visualization, 3) tracheal intubation, and 4) insertion of endotracheal tube into the glottis (Robitaille et al, 2008 p 936). The scholars performed such statistical tests as analysis of variance to compare the motion of every spine segment during GVL and DL. Additionally, they applied Man-Whitney Test to measure the degree of visualization in each method.
The study indicates that DVL and DL produce similar motions of cervical spine. Furthermore, the motion of C-spine at different stages of DVL and DL was the same. If they were some differences they were statistically insignificant. Yet, their findings also suggest that DVL provides better opportunities for glottic visualization and this can be viewed as an advantage of this technique. Overall, the authors believe that their findings are similar to those of other researchers, for example, Turkstra et al (2005).
The scholars conclude that both DL and GVL can be equally successful for orotracheal intubation. As it has been said before GVL can yield a more superior degree of visualization. Yet, the researchers also point out that the findings of this study cannot be regarded as conclusive since these results cannot be applied to the patients who do have a certain C-spine pathology or injury (Robitaille et al, 2008, 940). This is the main limitation of this research. Another problem that scholars identify is the possibility that the degree of C-spine movement was determined by the order in which two procedures were performed. These limitations do not undermine the validity of the findings but they do suggest more extensive research should be done. Moreover, we should take into account the sample size of the study, in particular, only twenty patients. It is not quite sufficient for this clinical trial.
At the beginning, the authors say that there is no consensus among physicians as to which tracheal intubation method is most suitable for the patients with C-spine injury. In order better to evaluate the efficiency of GlideScope videolaryngoscopy and direct laryngoscopy, one should take into account those circumstances which can lead to the failure of these procedures. For instance, if we are speaking about GlideScope videolaryngoscopy, we should mention that patients with a shorter thyromental distance, neck pathologies, scars, or radiation changes are more likely to have a failed videolaryngoscopy (Aziz et al, 2011, p 34). Other researchers such as Michael Aziz et al argue that GVL does provide better laryngeal views but it does not mean that the success rate of this procedure is much higher especially if it is used on the patients requiring neck immobilization. Additionally, researchers need to consider that the efficiency of these methods may depend upon a specific type of C-spine injury, for instance, intervertebral disk injuries, acute cervical strains, dislocations, or fractures. These are the factors that anesthesiologists need to consider. The authors of the study admit that their research has some very significant limitations, for instance, they did not set a threshold for dangerous movement of C-spine. Moreover, they could not apply their findings to the actual C-spine injuries. Despite these limitations, one can argue that GVL can be used a good alternative to DL. Its overall, success rate is 97 per cent and it is often used in those cases when DL failed (Aziz et al, 2011, p 39). This is the main reason why is so widely used even despite the increased cost of this technique. Now glidescope is considered to be the gold standards or the most preferred form of cervical spine surgery in patients who need to be invasively ventilated (Denaro & D’Avella, 2009, p 64).
Currently, medical workers have yet to identify the most effective technique of tracheal intubation. Although GlideScope videolaryngoscopy has been widely adopted by anesthesiologists and surgeons; it still induces the motion of cervical spine which can be dangerous for a patient. The study which has been discussed, can be viewed a good attempt to compare direct laryngoscopy and videolaryngoscope; yet, it requires further research and verification of results.
Aziz M., Healy D., Kheperpal S., Fu R, et al. (2011). Routine Clinical Practice Effectiveness of the Glidescope in Difficult Airway Management: An Analysis of 2,004 Glidescope Intubations, Complications, and Failures from Two Institutions. Anasthesiology. 114 (1) 34 – 41.
Denaro V. D. (2009). Pitfalls in Cervical Spine Surgery: Avoidance and Management of Complications. NY Springer.
Robitaille A, Williams SR, Tremblay MH, Guilbert F, Thériault M, Drolet P. (2008).
Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus GlideScope videolaryngoscopy. Anesthesia & Analgesia, 106(3):935-41.
Turkstra T, Craen R, Pelz D, Gelb A. (2005) Cervical spine motion: a fluoroscopic comparison during intubation with lighted stylet, GlideScope, and Macintosh laryngoscope. Anesthesia & Analgesia 101:910–5.