الفهرس 
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Abstract
Direct laryngoscopy is the primary method for performing intubation in the emergency department (ED).The direct laryngoscope blade is used to compress and displace the tongue with the goal of allowing operators to obtain a direct line of sight from their eye to the laryngeal inlet. Many anatomic or pathologic factors can make direct visualization of the airway difficult and sometimes even impossible
In the last decade, multiple video laryngoscopes have been introduced into clinical practice and have become more common in ED intubations. Video laryngoscopes incorporate a micro video camera on the undersurface of the laryngoscope blade and thus bring a view of the airway out of the patient and onto a video monitor. This provides the operator with an indirect view of the airway and thus circumvents the problems associated with achieving a direct line of sight to the airway.
The C-MAC video laryngoscope (C-MAC) (Karl Storz, Tuttlingen, Germany) is a video laryngoscope that is conceptually and structurally different from other video laryngoscopes. Rather than using blades with acute angles, the C-MAC incorporates a conventional Macintosh-type blade, with the addition of a micro video camera on the distal portion of the blade. Preliminary studies of the C-MAC in the operating room and out-of-hospital setting have demonstrated promising results. However, patients in the ED frequently are more difficult to intubate because of pathologic conditions and reduced physiologic reserves.
The Bonfils Retromolar Intubation Fiberscope is a rigid, straight fiberoptic device with a 40-degree curved tip. It is 40 cm long and 5 mm in outside diameter (OD). The 40-degree angle permits targeted intubation. The 110- degree angle of view ensures the necessary overview. It has a handle on which an eyepiece is mounted at the proximal end; the eyepiece is used for direct viewing or can be attached to a camera and video monitor system. A light source or a small battery handle can be attached to the stylet handle.
The aim of this study was to compare between conventional (Macintosh) direct laryngoscope, Bonfils fiberscope, C-MAC video laryngoscope for anticipated difficult airway management in the emergency department. This was to choose the device which may achieve the best first attempt of laryngoscopy and intubation for patients indicated for urgent laryngoscopy and intubation in the Emergency Department.
This study included 200 patients admitted to Emergency Medicine Department of Alexandria Main University Hospital (AMUH) and indicated for emergency endotracheal intubation.
- All patients were rapidly and thoroughly assessed using the ABCBE approach. History of difficult intubation was recorded and considered.
- Rapid assessment of the airway looking for signs of predicted difficult airwayusing the mnemonic LEMON and this includes:
• Look externally: e.g. fascial trauma, large incisors, beard or moustache, large tongue.
• Evaluate: The ‘3-3-2 rule’ It requires that the patient be able to place 3 of his or her own fingers between the open incisors, 3 of his or her own fingers along the floor of the mandible beginning at the mentum, and 2 fingers from the laryngeal prominence to the floor of the mouth.
• Mallampati classification (if the patient condition allows).
• Obstruction: such as laryngeal tumor, Ludwig’s angina, or neck hematoma.
• Neck mobility: it was assessed by having the patient flex and extend the head and neck through a full range of motion.
All patients were preoxygenated for at least 3 minutes with high flow oxygen before intubation. Functioning suction system, Oral and nasal airways (different sizes), ETT of different sizes, stylets, gum elastic bougie, syringes, Rescue ventilation devices such as laryngeal mask airway (LMA) or laryngeal tube (various sizes) and kits for emergency cricothyroidotomy were ready for use if needed.
Patients were divided randomly using the closed envelop technique into four equal groups (50 patients each) according to the device used during intubation.
group A (M gp): Patients were intubated using the conventional (Macintosh) direct laryngoscope.
group B (B gp): Patients were intubated using Bonfils fiberscope.
group C (C-M gp): Patients were intubated using C- MAC video laryngoscopy with the Macintosh blade.
group D (C-D gp): Patients were intubated using C- MAC video-laryngoscopy with the D- blade.
The four groups were compared as regards to indications for intubation, airway assessment score (LEMON score), number of intubation attempts, duration of intubation, success rate, glottic view, complications during intubations, and degree of difficulty using the device.
In this study, there were no statistically significant difference between the four groups as regards indications for intubation, diagnosis of the patients and difficult airway characteristics.
There was a difficulty in performing the Mallampati score for unconscious patients presented in the ED. Also there was difficulty in assessment of neck mobility as patients were unconscious and unable to obey commands to perform the test or due to a neck collar in place for suspected cervical cord injury.
Statistically significant higher number of intubation attempts was required in the conventional Macintosh group relative to the Bonfils fiberscope and the C-MAC VL with the D-blade with a p value of < 0.001 for both. The same was observed in the C-MAC VL with the Macintosh blade relative to the Bonfils fiberscope and the C-MAC VL with the D-blade with a p value of0.040, 0.004 respectively. Otherwise, there was no significant difference among the other groups regarding the number of attempts required for successful intubation.
The first intubation attempt success rate was statistically significantly higher in the Bonfils fiberscope group, the C-MAC VL with the Macintosh blade and the C-MAC VL with the D-blade relative to the conventional Macintosh. The same was observed in the Bonfils fiberscope group, the C-MAC VL with the D-blade relative to the C-MAC VL with the Macintosh blade. There was no statistically significant difference among the other groups as regards the first intubation attempt success rate.
The success rate of intubation was statistically significantly higher in the Bonfils fiberscope group, the C-MAC VL with either the Macintosh blade or the D-blade relative to the conventional Macintosh with a p value <0.001, 0.037, < 0.001 respectively. While there was no statistically significant difference among the other groups as regards the success rate for intubation.
Statistically significantly higher number of patients was judged to be easier regarding the technique of using the device in the conventional Macintosh relative to the Bonfils fiberscope with a p value of < 0.001. The same was observed in the C-M gp and C-D gp relative to the M gp with a p value of 0.037 and 0.017 respectively and also in the C-M gp and C-D gp relative to the B gp with a p value of < 0.001 in both. Otherwise there was no statistically significant difference between the C-M gp and C-D gp regarding the same parameter.
In addition, statistically significantly better glottic view was observed in the Bonfils fiberscope and the C-MAC VL with the D-blade relative to the conventional Macintosh group with a p value of < 0.001 for all. Otherwise, there was no significant difference among the other groups regarding the glottic view of the patient during intubation.
The duration for intubation was statistically significant higher in the conventional Macintosh group relative to the C-MAC VL with the Macintosh blade or D-blade with a p value of 0.002, < 0.001 respectively. The same was observed in Bonfils fiberscope group relative to the C-MAC VL with the Macintosh blade or D-blade with a p value of 0.005, < 0.001 respectively. Otherwise, there was no significant difference among the other groups regarding the duration of intubation.
There was no statistically significant difference between the four groups as regards complications during intubation. But there was statistically significant increase in the incidence of complications associated with intubation was observed with more intubation attempts in the four groups of patients.
Statistically significantly higher number of patients was judged to be easier regarding the technique of using the device in the conventional Macintosh relative to the Bonfils fiberscope with a p value of < 0.001. The same was observed in the C-M gp and C-D gp relative to the M gp with a p value of 0.037 and 0.017 respectively and also in the C-M gp and C-D gp relative to the B gp with a p value of < 0.001 in both. Otherwise there was no statistically significant difference between the C-M gp and C-D gp regarding the same parameter.
Also, statistically significant relation between LEMON score and success rate of intubation in M gp and C-M gp. The less LEMON score of the patient, the more was the success rate of intubation using the same device.
In this study, statistically significant relation between LEMON score and glottic view using Cormack and Lehane score was observed in the four groups using the different devices. As LEMON score of the patient was getting higher, the Cormack score was higher with less visualization of the glottic structures.
There was statistically significant relation between number of intubation attempts and glottic view of the patient in the 4 groups. As the glottic view of the patient was higher (Cormack 2-4) the more number on intubation attempts was observed.
In this study, there was no statistically significant difference between the four groups as regards complications during intubation. But there was statistically significant increase in the incidence of complications associated with intubation was observed with more intubation attempts in the four groups of patients.
In conclusion, the present study validates that: for patients in the emergency department with predicted difficult airway (based on the LEMON criteria) Bonfils fiberscope and C-MAC videolaryngoscopy with the D-blade reduced the number of intubating attempts and achieved high success rate (the best first attempt for endotracheal intubation). Also, Bonfils fiberscope and C-MAC videolaryngoscopy improves the glottic view visualization during endotracheal intubation. The study also validates that LEMON score is a good predictor of the glottic view of the patients, and subsequently the number of intubation attempts and the success rate for endotracheal intubation and it determined that the number of intubation attempts increases the incidence of complications during endotracheal intubation.
Thus in light of previous conclusion, one could recommend;
1. LEMON score is recommended to be used in the emergency department as a predictor for difficult airway.
2. Bonfils fiberscope and C-MAC videolaryngoscopy is recommended to be used safely in the emergency department to achieve the best first attempt for endotracheal intubation in patients with predicted difficult airway (based on the LEMON criteria).
3. Further clinical studies to compare and establish the role of C-MAC videolaryngoscopy (Macintosh blade and D-Blade) and Bonfils fiberscope in emergency department are recommended.
4. Training of every physician dealing with airway management on the use of C-MAC video-laryngoscopy (with its different blades) and Bonfils fiberscope is highly recommended.
5. Further studies on large number of cases and meta-analysis studies are recommended to develop evidence based recommendations for the use of video-laryngoscopy and Bonfils fiberscope during routine laryngoscopy