|Year : 2015 | Volume
| Issue : 3 | Page : 308-315
Tracheal intubation with the aid of fiberoptic bronchoscopy with or without the C-MAC device in patients with a suspected difficult airway undergoing elective uvulopalatopharyngoplasty
Khaled M Maghawry MD 1, Ayman A Rayan2
1 Department of Anesthesia, Faculty of Medicine, Ain Shams University, Cairo, Egypt
2 Department of Anesthesia, Faculty of Medicine, Menoufia University, Menoufia, Egypt
|Date of Submission||02-Jun-2015|
|Date of Acceptance||06-Jun-2015|
|Date of Web Publication||29-Jul-2015|
Khaled M Maghawry
Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain Shams University, PO Box 11591, Cairo
Source of Support: None, Conflict of Interest: None
Endotracheal intubation is considered as the definitive method of airway management. Difficulty encountered during direct laryngoscopy for the intubation process is one aspect of the overall problems in airway management. Fiberoptic bronchoscopy (FOB) represents a significant advancement in the management of patients with a difficult airway. C-MAC videolaryngoscopes present a new approach for the management of difficult laryngoscopy.
Patients and methods
Sixty patients, of both sexes, aged 20-50 years, ASA I-II, undergoing an elective uvulopalatopharyngoplasty surgery were included. Patients were allocated randomly to be intubated using FOB (F group) or FOB plus C-MAC videolaryngoscopy (F-CMAC group). Collected data included grades of the Cormack-Lehane laryngeal view, success or failure of the technique, the number of attempts, the duration of the successful attempt, and hemodynamic measurements throughout the intubation procedure. Complications (such as oxygen desaturation, patient distress, soft tissue damage, gagging/vomiting, bradycardia and hypotension, laryngospasm, and bronchospasm) were recorded.
There was a significant decrease in the duration of the successful attempt, the number of intubation trials, and Cormack-Lehane grades regarding the laryngeal view as well as a decrease in the number of patients who needed facilitating techniques in group F-CMAC compared with group F. No significant difference was found on comparing the heart rate, the mean arterial pressure, and the incidence of complications during intubation between the two groups.
The C-MAC videolaryngoscope with fiberoptic bronchoscopy allows a significantly faster intubation time, with a decrease in the duration of the successful attempt, fewer intubation trials, and a better grade of laryngeal views assessed by Cormack-Lehane grades, with a decrease in the number of patients who needed facilitating techniques and a comparable incidence of complications during intubation compared with fiberoptic alone for tracheal intubation in patients with a suspected difficult airway undergoing elective uvulopalatopharyngoplasty.
Keywords: airways, anesthetic techniques, fiberoptic, tracheal intubation, videolaryngoscopes
|How to cite this article:|
Maghawry KM, Rayan AA. Tracheal intubation with the aid of fiberoptic bronchoscopy with or without the C-MAC device in patients with a suspected difficult airway undergoing elective uvulopalatopharyngoplasty. Ain-Shams J Anaesthesiol 2015;8:308-15
|How to cite this URL:|
Maghawry KM, Rayan AA. Tracheal intubation with the aid of fiberoptic bronchoscopy with or without the C-MAC device in patients with a suspected difficult airway undergoing elective uvulopalatopharyngoplasty. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2021 Oct 22];8:308-15. Available from: http://www.asja.eg.net/text.asp?2015/8/3/308/161690
| Introduction|| |
Endotracheal intubation is considered as the definitive way for airway management  . Anesthetists perform endotracheal intubation in the operating room under controlled circumstances  ; however, the exposure with direct laryngoscopy is difficult in 6-10% of the patients  , and failed intubations occur in 0.13-0.3% of the cases  . Successful management of both expected and unexpected difficult laryngoscopy is an essential component of safe anesthesia care , .
A difficult intubation is defined as 'more than three attempts to intubate in 10 min of time'  , or whereby 'it is not possible to visualize any portion of the vocal cords with conventional laryngoscopy' or 'intubation that requires more than one attempt, a change in blade, an adjunct to direct laryngoscopy, or the use of alternative devices'  . Unfortunately, the available techniques of airway assessment are poor screening tests for difficult laryngoscopy due to their overall low positive predictive value  .
The technique of fiberoptic intubation [fiberoptic bronchoscopy (FOB)] was first performed using a choledoscope, by Murphy  in 1967, in a patient with Still's disease. Rosenblatt et al.  indicated that FOB intubation was then available with 99% of the surveyed ASA members in the USA. By the late 1980s, it was recognized that the use of FOB represents such a significant advancement in the management of patients with difficult airway that experts stated that no anesthesiologist can afford to be not well familiar with the technique  .
The C-MAC is a modification of the Storz Berci-Kaplan DCI videolaryngoscope (Karl Storz Endoscopy Inc., Tuttlingen, Germany)  . This portable videolaryngoscope incorporates a complementary metal oxide semiconductor video chip at the tip of the blade with a 2-mm digital camera, and a magnified image is displayed on a screen. The user's 'eye' is therefore positioned at the tip of the instrument, extending the viewing angle from the standard 15-80°  .
The C-MAC videolaryngoscope presents a new approach for the management of difficult laryngoscopy as it provides a panoramic view of the glottis, without the need to align the axis, resulting in improved glottis exposure by at least one grade in the Cormack-Lehane (C-L) scale, as compared with conventional laryngoscopy  . Also, the C-MAC displaces soft tissues in a manner similar to a classic Macintosh laryngoscope, affording room for tracheal tube insertion and consequently lesser need for intubating adjuncts, such as a stylet , .
Hence, the aim of this study was to determine whether the addition of C-MAC videolaryngoscopy to FOB during intubation will offer an ease in patients with regard to positive predictors of a difficult airway, undergoing elective uvulopalatopharyngoplasty (UPPP) regarding glottis visualization, successful first-attempt intubation, the duration of the successful attempt, hemodynamic changes, and the incidence of complications during the intubation procedure.
| Patients and methods|| |
A prospective, randomized, single-blinded clinical study was carried in Prince Salman Hospital in the Kingdom of Saudi Arabia from March 2014 to March 2015. After obtaining approval by the Hospital Ethics Committee and written informed consents from the patients, 60 patients were enrolled in the study. They were of both sexes, their age ranged from 20 to 50 years, American Society of Anesthesiologists (ASA) physical status I-II, scheduled to undergo an elective UPPP surgery. Patients were prospectively allocated randomly by a computer-generated table of random numbers to be intubated using either a fiberoptic bronchoscope (F group) or a fiberoptic bronchoscope plus C-MAC videolaryngoscopy (F-CMAC group).
Exclusion criteria included patients with ASA physical status III or IV, apparent airway abnormalities, a history of laryngopharyngeal surgery or coagulation disorders, a BMI more than 40%, a high risk of regurgitation-aspiration (previous upper-gastrointestinal-tract surgery, known hiatus hernia, esophageal reflux, peptic ulceration, or not fasted), cardiovascular system instability (uncontrolled hypertension, ischemic heart disease, hypotension), a recent respiratory-tract infection or hyperactive airway disease, hepatic or renal disorders, and anticipated impossible intubation cases.
Patients were assigned to one of the two groups using a computer-generated random number table. After recruitment, the enrolling investigator opened a sealed opaque envelop. Participants were blinded to their group allocation. All intubations were performed by experienced anesthetists with each of the devices being tested.
All patients underwent a preoperative airway evaluation to ascertain predictive indices for difficult intubation; hence, preoperative airway assessment was performed by mouth opening, the interincisor distance, the thyromental distance described by Patil et al.  , the view of the oropharynx on mouth opening described by Mallampati et al.  , and modified by Samsoon and Young  , the ability to protrude the lower jaw in front of the upper jaw  , the mentothyroid distance, and cervical extension of the head (atlanto-occipital extension according to Bellhouse)  .
All patients prepared by keeping them fasting preoperatively. On arrival to the receiving area, all patients were premeditated with glycopyrrolate 0.2 mg intravenously 20 min before the start of anesthesia. Also, all patients, before airway manipulation, received topical anesthesia of the airway structures with local anesthetic instillation according to the spray-as-you-go (SAYGO) technique using lidocaine 10% spray and lidocaine gel 2% for the oral cavity, the tongue, and the pharynx 10 min before the induction of anesthesia. Dexmedetomidine [Precedex 200 μg/2 ml (Hospira, Lake Forest, Illinois, USA)] reconstituted to a concentration of 4 μg/ml was prepared, and intravenous infusion was started with 0.5 μg/kg as the loading dose over 10 min before the induction of anesthesia, with monitoring of hemodynamics and oxygen saturation in the receiving area.
In the operating room, before the induction of anesthesia, the following standard monitoring (Aisys; Datex-Ohmeda Inc., a General Electric Company, carrying out business as GE Health Care, Madison, Wisconsin, USA) was applied: a five-lead ECG to monitor the heart rate (HR), noninvasive blood pressure and oxygen saturation (SpO 2 ) were continuously monitored, together with the monitoring of the depth of anesthesia using the BiSpectral Index (Aspect Medical System Inc., registered in USA, EU, and other countries 194-0068 3.01). Then, intravenous lactated Ringer's solution infusion 6-8 ml/kg was started.
All patients were positioned supine on the operating table, with the head resting on a jelly doughnut. Preoxygenation was performed with high-flow oxygen for 3 min before starting the inhalational induction with sevoflurane administered through a facemask with FiO 2 100%, according to the inhaled induction regimen at the tidal volume until achieving a Guedel grade III anesthetic depth in plane I. Patients maintained spontaneous ventilation, confirmed through capnography, with oxygen saturation reading around 95-100%, stable hemodynamic data, and BiSpectral Index records of 40-55, together with intravenous ondansetron 0.1 mg/kg, dexamethasone 0.1-0.2 mg/kg, and continuous dexmedetomidine intravenous infusion at a rate of 0.3-0.6 μg/kg/h.
In group F, a suitable orotracheal tube (7-8 mm diameter in men, and 6.5-7.5 mm diameter in women; Mallinckrodt Medical, Athlone, Ireland) was guided into place with the bronchoscope. After orientation and localization of the laryngo-epiglotteal region, an epidural catheter was introduced through the working channel of the bronchoscope, for the administration of topical anesthesia to the supraglottic region, the epiglottis, the arytenoid, the glottis, and the trachea, with the administration of 10 ml of 2% lidocaine according to SAYGO. In addition, 2 ml of lidocaine 2% was administered on the vocal cords immediately before passage.
Fiberoptic intubation involves threading an endotracheal tube over the shaft of a flexible fiberoptic scope. The scope is passed through the mouth of the patient, into the pharynx, and through the vocal folds into the patient's trachea. On visual confirmation of tracheal rings and carina, the fiberoptic scope is held steady, while the endotracheal tube is advanced over the fiberoptic bundle into the patient's airway; the endotracheal tube was positioned ~3 cm above the carina. Once the endotracheal tube is in place, the scope is removed and the cuff inflated, with further confirmation of proper intubation using capnography. After insertion of the orotracheal tube, propofol 1-2 mg/kg intravenously, rocuronium 0.6 mg/kg intravenously, and fentanyl 1-2 μg/kg were administered to induce general anesthesia; the lungs were mechanically ventilated using volume-controlled mode to maintain normocapnia (end-tidal CO 2 30-35 mmHg).
In group F-CMAC, the same procedure as in the F group was performed with the use of C-MAC ((Karl Storz Endoscopy Inc.) as usual in the intubation at first, and then after adjustment of the exposure of the view; the FOP was used to complete the intubation procedure (the advantage of using a C-MAC videolaryngoscope is bypassing all airway path till the epiglottis and the glottis area) [Figure 1] and [Figure 2].
In both groups, the laryngeal view was assessed by the Cormack and Lehane  classification system for the grading of the laryngeal view, which had four grades. Time was recorded in seconds, from the start of insertion of FOP in the oral cavity till successful intubation, when the endotracheal tube cuff was inflated, and detection of end-tidal carbon dioxide. If it was necessary, facilitating techniques such head flexion and jaw thrusts were utilized. The inability to intubate was considered as failed intubation and excluded from the study, and the patient was then intubated using a different modality.
Data collected included grades of the Cormack-Lehane laryngeal view, success or failure of the technique, the number of attempts, the duration of the successful attempt (the interval between the time of insertion of the device and the detection of end-tidal carbon dioxide)  . Intubation success was defined as confirmation of the endotracheal tube placement by end-tidal carbon dioxide with a single trial of the technique  , whereas failure of intubation was defined as any intubation attempt of more than 120 s duration or an inability to place the endotracheal tube successfully into the trachea  . Hemodynamic measurements [HR and noninvasive mean arterial blood pressure (MAP)] were performed throughout the intubation procedure.
Complications were registered during and after the procedure, including oxygen desaturation (oxygen saturation <90%), patient distress, soft tissue damage such as bleeding, mucosal damage, and ulceration, gagging/vomiting (caused by touching the posterior pharyngeal wall with a suction catheter), vasovagal stimulation causing bradycardia and hypotension, laryngospasm, and bronchospasm  .
On the basis of the data from previous studies, it was calculated that a sample size of 25 patients per group will achieve 80% power to detect a relevant difference of 30 s in successful intubation time between the two techniques with a significance level (α) of 0.05 using a two-sided two-sample t-test; 30 patients per group were included to replace any drop outs.
The statistical analysis was performed using SPSS software package version 17 (SPSS Inc., Chicago, Illinois, USA). Data were expressed as the mean (SD), the median (interquartile range), the ratio, or numbers (%). Student's t-test was used to analyze parametric data; discrete (categorical) variables were analyzed using the χ2 -test, and nonparametric data were compared using the Mann-Whitney test, with P values less than 0.05 considered statistically significant.
| Results|| |
A total of 60 adult patients were included in this study, four patients refused consent, and another two cases were missed throughout the course of the study in group F.
There was no statistically significant difference between the two groups in the patients' demographic data with regard to their age, sex, weight, ASA classification, and duration of surgery [Table 1].
Regarding the intubation conditions, there was a highly significant difference in the duration of the successful attempt (the interval between the time of insertion of the device and the detection of end-tidal carbon dioxide) with a shorter duration in group F-CMAC compared with group F [Table 2].
Also, regarding the laryngeal view, which was assessed by Cormack-Lehane grades, there was a significant difference in the grading, with a lower grade in group F-CMAC compared with group F. Also, there was a highly significant difference in the number of intubation trails, with less trials in group F-CMAC compared with group F [Table 2].
Regarding the facilitating techniques such as jaw thrusts and head flexion, there was a nonsignificant difference regarding the number of patients who needed these techniques in group F-CMAC compared with group F [Table 2].
Regarding the changes in the HR throughout the intubation procedure, there was no significant change in the HR in group F-CMAC at the preoperative (baseline) measurement and throughout the intubation procedure from 1 up to 10 min after starting the intubation procedure when compared with group F at the same time points [Table 3].
|Table 3: Changes in the heart rate (beats/min) throughout the intubation procedure|
Click here to view
Regarding the changes in the MAP throughout the intubation procedure, there was no significant change in group F-CMAC at the preoperative (baseline) measurement and throughout the intubation procedure from 1 up to 10 min after starting the intubation procedure when compared with group F at the same time points [Table 4].
|Table 4: Changes in the mean arterial blood pressure (mmHg) throughout the intubation procedure|
Click here to view
Regarding the complications during intubation such as desaturation, hypotension, hypertension, bradycardia, or tachycardia, the number of patients who had these complications was less in group F-CMAC than in group F, but the difference was statistically nonsignificant [Table 5].
Regarding the number of patients who had trauma and mucosal ulceration or bleeding, it was more in group F-CMAC compared with group F, with the difference being statistically nonsignificant [Table 5]; however, the number of patients who had gagging and vomiting, laryngeal spasm, or bronchospasm was less in group F-CMAC compared with group F, also with a nonsignificant difference [Table 5].
| Discussion|| |
Despite many recent advances in the equipment for difficult airway management, it remains the leading cause of the most serious adverse outcomes in anesthesia. Fiberoptic airway management is among the available techniques for difficult airway management. It requires more advanced skills than most other techniques. Fiberoptic is frequently used when difficult airway management is predicted, but may also be appropriate when unexpected difficulty occurs. This technique can be performed in combination with the use of the C-MAC videolaryngoscope to decrease the time and to improve the quality of the intubation technique  .
The C-MAC videolaryngoscope is a relatively new device with the unique advantage that it provides the possibility to obtain both a direct laryngoscopic view and a camera view that is displayed on the video screen, in contrast to many previous videolaryngoscopes  .
All patients, before airway manipulation, received topical anesthesia of the airway structures with local anesthetic instillation according to the SAYGO technique to avoid the use of nondepolarizing muscle relaxants in the induction of anesthesia.
Our findings in the present study demonstrated that the use of the C-MAC videolaryngoscope in combination with fiberoptic in the setting of a predicted difficult airway patient undergoing elective uvulopalatopharyngoplasty (UPPP) resulted in a higher success rate of tracheal intubation with a decrease in the duration of intubation, improvement of the laryngeal view, and less complications associated with the intubation compared with the use of fiberoptic alone. These data provide evidence for the clinical effectiveness of the C-MAC videolaryngoscope in managing difficult airways in combination with fiberoptic in anesthesia care.
Regarding the intubation conditions, there was a highly significant decrease in the duration of the successful attempt (the interval between the time of insertion of the device and the detection of end-tidal carbon dioxide) in group F-CMAC compared with group F [Table 2]. This could be explained by the fact that the C-MAC blade will lift the patient's tongue and jaw, and so could achieve a clear airway for fiberoptic view. This was tried before by Yuan et al.  in 2011 who had tried with success, the combined use of an Airtraq optical laryngoscope with an FOB in patients with a difficult airway. Also, our finding agreed with the results of Reus et al.  in 2012, who demonstrated that a combination of C‐MAC with a D‐blade with a flexible FOB, as a guide for intubation, may be an alternative for a hockey stick formed stylet. Moreover in 2011, Bradbury et al.  found that an experienced anesthetist, who uses the C-MAC for intubation, will intubate with the C-MAC faster than the Macintosh.
The laryngeal view was assessed by the Cormack and Lehane  classification system for the grading of the laryngeal view, which had four grades: grade 1, visualization of the entire laryngeal aperture; grade 2, visualization of parts of the laryngeal aperture or the arytenoids; grade 3, visualization of only the epiglottis; and grade 4, visualization of only the soft palate. Regarding the assessment of the laryngeal view by Cormack-Lehane grades, there was significant improvement in the grading in group F-CMAC compared with group F, and there was significant decrease in the number of intubation trails in group F-CMAC compared with group F [Table 2]. This was in accordance with Meininger et al.  in 2010 who found that a C-MAC videolaryngoscope enhances the laryngeal view in patients with apparently normal and anticipated difficult airways. Furthermore, Byhahn et al.  in 2010 stated that a C-MAC videolaryngoscope enhances the laryngeal view effectively in patients with limited interincisor distance. It has also been reported by Cavus et al.  in 2010 that the use of the C-MAC can improve the view of the larynx and facilitate intubation in an unanticipated difficult airway. Cavus et al.  in 2011 found that in patients with an impeded glottic view (C/L≥2a), the C-MAC size 4 may reduce the number of C/L 3 or C/L 4 views, and therefore facilitate intubation.
Regarding the facilitating techniques such as jaw thrusts and head flexion, there was a statistically nonsignificant decrease in the number of patients who needed these facilitating techniques in group F-CMAC compared with group F [Table 2], as the CMAC blade will lift the patient's tongue and jaw, and so can achieve a clear airway, which subsequently decreases the need for these facilitating techniques; this was in agreement with Jungbauer et al.  in 2009, who stated that the C-MAC videolaryngoscope has been shown to perform better in terms of a shorter intubation time, a higher success rate, and less number of optimizing maneuvers in an anticipated difficult airway.
However, Hodgetts et al.  in 2011 found the patients in the C-MAC group to have a higher number of maneuvers even though the laryngoscopic views were almost identical in the two groups, but this did not reach statistical significance, and they were comparing with a Macintosh laryngoscope for tracheal intubation. However, Aziz et al.  in 2012 studied the comparative effectiveness of the C-MAC videolaryngoscope and the direct laryngoscope in the setting of the predicted difficult airway and found that tracheal intubation with the C-MAC required less external laryngeal manipulation or the use of a gum-elastic bougie, and they suggested that a better laryngeal view and familiar blade curvature of the C-MAC blades eased intubation difficulty.
Regarding the hemodynamic changes, there was a statistically nonsignificant change in HR and MAP on comparing group F-CMAC with group F at preoperative (baseline) measurements and throughout the intubation procedure from 1 to 10 min after starting the intubation procedure [Table 3] and [Table 4].
This was in agreement with the randomized controlled trial study of Ng et al.  in 2012, which compared the McGrath videolaryngoscope with the C-MAC videolaryngoscope in the intubation of adult patients with potential difficult airways. They found that in both groups, patients showed significant changes in the HR and the arterial pressure from baseline to after intubation. However, there was no statistically significant difference in the changes between the two groups. In addition, McElwain and Laffey  in 2011 described the effects of laryngoscopy and tracheal intubation on the MAP and the HR, which was found to be relatively modest. The HR increased significantly in all groups after tracheal intubation, but had returned to baseline within 5 min in all groups, with no significant difference observed between groups. The MAP decreased significantly in all groups after induction of anesthesia, but no significant difference was observed between groups at any time point.
Regarding the number of patients who had complications during intubation (such as desaturation, hypotension, hypertension, bradycardia or tachycardia, gagging and vomiting, laryngeal spasm, or bronchospasm), the number was nonsignificantly lesser in group F-CMAC compared with group F. However, the number of patients who had trauma and mucosal ulceration or bleeding complications was nonsignificantly more in group F-CMAC compared with group F [Table 5].
The C-MAC videolaryngoscope has an original British Macintosh blade with a low profile that facilitates insertion in patients with limited mouth opening. Besides video-assisted laryngoscopy, direct laryngoscopy is also possible. Even if the laryngeal view is poor with direct laryngoscopy, some straight line between the mouth and the larynx still exists in most cases. This line allows for advancing the endotracheal tube through the upper airway under satisfying direct vision, thereby reducing the risk of injury to oral and pharyngeal structures  .
This was correlated with the data of McElwain and Laffey  in 2011, who found a nonsignificant difference in the incidence of complications between the groups when compared Airtraq, Macintosh, and C-MAC groups. In addition, there was no incidence of dental or other airway trauma observed in any group; arterial hemoglobin oxygen saturations showed no significant difference between the three groups, but were maintained best in patients intubated with the Airtraq group.
Furthermore, Aziz et al.  in 2012 stated that the incidence of complications, such as lip trauma, dental trauma, pharyngeal injury, tracheal injury, or sore throat, was not significantly different after the use of either the C-MAC device or direct laryngoscopy.
Further studies to compare different videolaryngoscope types in association with fiberoptic to be used in patients with different types of airway problems will be useful to assist anesthetists in selecting the most appropriate device in each individual clinical scenario.
| Conclusion|| |
The C-MAC videolaryngoscope with fiberoptic bronchoscopy allows a significantly faster intubation time with a decrease in the duration of the successful attempt, fewer intubation trials, a better Cormack-Lehane grade of laryngeal views, a smaller number of patients needing facilitating techniques, and comparable incidence of complications during intubation compared with fiberoptic alone for tracheal intubation in patients with suspected difficult airway undergoing elective UPPP surgery.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]