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Rigid endoscope-assisted orotracheal intubation for vallecular cyst surgery in neonates and young infants
International Journal of Pediatric Otorhinolaryngology 110 (2018) 61–66
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Rigid endoscope-assisted orotracheal intubation for vallecular cyst surgery in neonates and young infants
T
Haoyue Tana,c,e,f,1, Qi Huangc,1, Antoine Paula,c,1, Wei Wangd, Jingjie Lib,d,∗∗, Huan Jiaa,c,e,f,∗ a
Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, No.639 Zhizaoju Road, Shanghai, 200011, China b Anesthesiology Department, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639 Zhizaoju Road, Shanghai, 200011, China c Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1665 Kongjiang Road, Shanghai, 200092, China d Anesthesiology Department, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China e Ear Institute, Shanghai Jiaotong University School of Medicine, No. 390 Yanqiao Road, Shanghai, 200125, China f Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, No. 390 Yanqiao Road, Shanghai, 200125, China
A R T I C LE I N FO
A B S T R A C T
Keywords: Intubation Endoscopes Laryngeal diseases Infant newborn Surgery Airway management
Objectives: To investigate the outcomes of rigid endoscope-assisted orotracheal intubation (REI) in neonates and young infants with difficult airway conditions as an alternative intubation technique when more specific airway instruments are not available in most developing countries, and to evaluate the safety and advantages of this method. Methods: Neonatal and young infantile patients undergoing vallecular cyst surgery with a Cormack-Lehane Grade 3 or 4 glottic view between June 2013 and June 2015 were studied. Fifteen patients were intubated using rigid endoscopic assistance. Fifteen other patients who were intubated using the conventional technique were selected from the previous consecutive cases and used as a matched control group. Results: REI was successfully performed in all 15 patients in one intubation attempt. The anesthetic preparation duration for the REI group was 6 min (interquartile range 5–7 min), which was shorter than the anesthetic preparation duration for patients intubated using the conventional technique (15 min [interquartile range 10–20 min], p < 0.001). The time required for intubation with a rigid endoscope was 66.5 s (interquartile range 58–74 s). No volume reduction of cysts or tracheotomies was needed in the REI group, and no cysts were ruptured nor did laryngeal mucosa damage occur with this technique. Among patients of conventional group, one required a tracheotomy, and four required cyst volume reduction by needle aspiration. No residual lesions or recurrence were observed during one year of postoperative follow-up in the REI group, and two recurrences were observed in the conventional group. Conclusion: REI, which used common pieces of equipment in an otolaryngology operating room, may be a safe and feasible alternative for intubation in neonatal and young infantile patients with vallecular cysts or other difficult airway conditions.
1. Introduction
death. An elective operation during the first few months of life is necessary. However, anesthetic management of the upper airways of these patients can present a great challenge because their laryngeal morphologies (e.g., supraglottic location of cysts, small laryngeal cavities, etc.) make glottic exposure much more difficult [3–5]. In addition, these patients have usually suffered from respiratory distress for several days or weeks, which results in poor compensation capacity for anoxia;
Vallecular cysts are ductal cysts caused by mucus retention at the tongue base due to obstruction of the collecting ducts. The prevalence of vallecular cysts ranges from 1.82 to 5.3 cases per 100,000 live births [1,2]. Cysts present as airway obstruction or feeding difficulty in the neonatal population and can progressively lead to failure-to-thrive or
∗
Corresponding author. Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, No 639 Zhizaoju Road, Shanghai 200011, China. Corresponding author. Anesthesiology Department, Shanghai Ninth People's Hospital, No 639 Zhizaoju Road, Shanghai 200011, China. E-mail addresses: [email protected] (H. Tan), [email protected] (Q. Huang), [email protected] (A. Paul), [email protected] (W. Wang), [email protected] (J. Li), [email protected] (H. Jia). 1 Haoyue TAN, Qi HUANG and Antoine PAUL contributed equally to this work. ∗∗
https://doi.org/10.1016/j.ijporl.2018.04.023 Received 9 March 2018; Received in revised form 16 April 2018; Accepted 19 April 2018 Available online 25 April 2018 0165-5876/ © 2018 Elsevier B.V. All rights reserved.
International Journal of Pediatric Otorhinolaryngology 110 (2018) 61–66
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Fig. 1. MRI T2-weighted axial (A) and coronal (B) views. MRI revealed a cystic mass on the epiglottic vallecula and that the upper airway was narrowed. T, tumor; H, hypopharynx; E, epiglottis.
(the maximum diameter in coronal, sagittal or transverse planes) were also collected (Fig. 1). Ethical approval for this study was provided by the Ethical Committee of Xinhua Hospital, which is affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China. Due to the difficulty and high risk of intubating infants with upper airway obstructions, conventional intubation was not performed after the first successful case was intubated using rigid endoscopic assistance. For comparison, a matched control group was selected from previous consecutive patients who underwent conventional intubation during the similar time frame (seventeen months) (Table 1). The criteria for the control group were as follows: patients were treated by the same medical team (senior surgeon and senior anesthetist); were less than one year of age; and had complete medical records.
therefore, temporary hypoxemia occurs more frequently during intubation, and patients recover slowly with oxygen. All of these factors make intubation of these patients a difficult and high-risk procedure. In the past, blind intubation by a senior anesthetist [6,7] or intubation after volume reduction of cysts [8–10] was performed commonly for these cases; however, these methods can induce laryngeal mucosal damage or cyst deformation and increase the difficulty of surgical resection [1,11]. Intubation performed with rigid endoscopic assistance has been reported in difficult cases of adult patients with epiglottic cysts [12] and in infants with Pierre-Robin syndrome [13]. This method had some advantages and is convenient in cases in which more specific advanced instruments are not available, generally in developing countries. Since June 2013, we have used rigid endoscopicassisted orotracheal intubation (REI) in neonates and young infants with a Cormack-Lehane (C-L) Grade 3 or 4 glottic view. This article aims to present the outcomes of this technique in these difficult airway conditions, to evaluate its safety and advantages, and to compare it with other techniques.
2.2. Endoscope system Endoscopic visualization was achieved using a general rigid otolaryngology endoscope system (Karl Storz GmbH and Co. KG, Tuttlingen, Germany) including 0°, 30° or 70° angled endoscopes (4 mm in diameter and 175 mm in length). The 0° endoscope was used first, and the 30° or 70° angled endoscopes were substituted if the glottis could not be clearly exposed. This system was also subsequently used for the surgical resection of the vallecular cysts.
2. Materials and methods 2.1. Patients Fifteen consecutive neonatal and infant patients with symptomatic vallecular cysts between June 2013 and June 2015, who were intubated using rigid endoscopic assistance, were included in the study. The transoral microsurgeries used to treat these patients' vallecular cysts were performed by the same medical team. The surgical records, discharge summaries, anesthetic records and follow-up records were collected. When available, the radiologic reports regarding the cysts sizes
2.3. Intubation procedures The airway conditions of all patients were evaluated prior to surgery, and their glottic views were assigned a C-L Grade [14]. The steps in the standard procedure for orotracheal intubation using endoscopic video visualization were as follows:
Table 1 Comparison between two techniques. Intubation technique
Case (n)
Age at Surgery (days, median, [IQR])
Sex
Cyst Size (cm, median, [IQR])
CormackLehane grading
Anesthetic preparation duration (min, median, [IQR])
Intubation duration (second, median, [IQR])
Intubation attempt (n, median, [IQR])
Volume reduction (n)
Tracheotomy (n)
Residual after 1 year (n)
REI
15
1 [0.95–1.5]a 1 [0.88–1.5]
66.5 [58.5–74.5] N/Ab
0
4
1
4
0.636
–
1 [1-1] 3 [2–3] < 0.001
0
3–4
6 [5–7] 15 [10–20] < 0.001
0
15
10 Male 5 Female 8 Male 7 Female –
3–4
Conventional technique p-value
60 [34–70] 56 [40–80] 0.881
–
–
–
–
IQR = interquartile range. REI = rigid endoscope-assisted orotracheal intubation. a 13 cases with datas of images were included. b no datas for the cases of conventional technique. 62
–
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2.3.2. Intubation period The otolaryngology surgeon stretched the mouth and pushed the tongue base up using a direct laryngoscope (Seward blade) in his left hand, then held and guided the endoscope gently but quickly with the other hand to expose the glottis. If the glottis could not be exposed well using the 0° endoscope, the 30° or 70° angled endoscope was quickly substituted. All laryngeal structures, including the epiglottis and arytenoid region, were in the endoscopic view for ease of tube insertion. Finally, the anesthetist introduced the endotracheal tube (ETT) into the hypopharyngeal cavity using the naked eye until the tips of the tube were visible on the screen, and then the tube was advanced into the trachea via video visualization (Fig. 2 and Fig. 3). If oxyhemoglobin desaturation progressively decreased to below 70%, mask ventilation with pure oxygen was administered immediately at any period during the previously described steps.
2.3.1. Induction period (pre-intubation) Patients were premedicated with atropine (0.1 mg kg−1) and dexamethasone (0.3 mg kg−1) by intravenous injection. General anesthesia was induced via inhalation of 8% sevoflurane associated with 100% oxygen at a flow rate of 5–6 L min−1, without the use of a muscle relaxant. An injection of dexmedetomidine at a dose of 2 μg kg−1 over 10 min was administered, followed by a continuous infusion at 0.4 μg kg−1 h−1 until the end of the surgery. When the patient became unconscious, the inhaled sevoflurane concentration was reduced to 4–6% based on the respiratory frequency. The tidal volume was maintained for at least 5 min to allow adequate time for alveolar and brain sevoflurane partial pressures to equilibrate before exposing the larynx. This is consistent with a previous report that stated that the minimum alveolar concentration for endotracheal intubation (MACEI) value for sevoflurane in infants of 1–6 months of age was 3.2–3.3% [5]. Lidocaine (2–4%) was applied topically around the larynx with a sprayer, sometimes blindly. The maximum dose of topical lidocaine anesthesia was 4 mg kg−1.
2.3.3. Operation period (post-intubation period) After intubation, remifentanil at a flow rate of 0.05 μg kg−1 minute−1 and propofol at a flow rate of 8–10 mg kg−1 h−1 were used
Fig. 2. Views and steps for glottis exposure using a standard rigid endoscope. A. Visualization when the lens was at the level of the lips, similar to the view using a direct laryngoscope. The vallecular cyst can be seen, but the epiglottis cannot. B. With advancement of the endoscope to the hypopharynx, the epiglottis can be visualized. C. After adjusting the lens, the glottis can be located, and intubation can be assisted. 63
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Fig. 3. Posture for rigid endoscopic-assisted intubation. The otolaryngologist held the direct laryngoscope in his left hand and the rigid endoscope in his right hand. The anesthetist managed the endotracheal tube insertion. The rigid endoscope and direct laryngoscope could be adjusted at any time to provide a better view for intubation.
3.2. Surgical outcomes
for maintenance anesthesia until the end of surgery.
In this series, the surgeries were performed under favorable conditions, and no surgical complications occurred. No residual lesions or recurrence of cysts were observed during 1 year of postoperative follow-up in the REI group. Two recurrences were observed in the conventional intubation group.
2.3.4. Data collection One additional mask ventilation during the intubation period was noted as one additional intubation attempt. On the anesthetic records, the time at the beginning of induction period and at the end of intubation period was routinely noted, and this interval was considered as the anesthetic preparation duration in this study. In the REI group, the pure duration of intubation could be collected from the recorded endoscopic video.
4. Discussion Infants with vallecular cysts in this study were generally emaciated and thinner than same-aged individuals and commonly had associated laryngomalacia. The median age of our series was at 60 days. Consequently, the space and view for intubation was very limited. Vallecular cysts also deformed and shifted the epiglottis caudally, making the glottis more difficult to visualize (Fig. 4A). Therefore, common techniques for improving glottic exposure [15] (e.g., anteriorlateral neck pressure for moving the vocal folds caudally and ventrally) were not helpful. When visualization of the glottis is difficult, repeated and/or blind intubation attempts are usually performed [6,7], which prolongs the anesthetic duration and provokes secondary mucosal damage and cyst deformities. The unclear field of vision and the incorrect identification of tumor boundaries may make complete resection less accurate [1,11] and may be the main reason for 2 recurrent cases among patients who were intubated using the conventional technique. In our experience, REI provides satisfactory visualization of the glottis and quick intubation. Nevertheless, this technique required at least three hands (one for the endoscope, one for the direct laryngoscope, one for intubation, and another for a suction tube if needed). Therefore, collaboration between otolaryngologists and anesthetists is essential. The direct laryngoscope was used to enlarge the narrow space by opening the mouth and pushing the tongue base anteriorly to allow the rigid endoscope to move freely without damaging the mucosa and to avoid bending of the endoscope, which can result in damage to this equipment. A rigid suction tube was useful for removing local mucus and liquid because it is more easily controlled than a flexible suction tube and can also be used to drag or push the epiglottis if needed. A rigid endoscopic system, a common piece of equipment in otolaryngology surgical suites worldwide, and otolaryngology surgeons are skilled at using it, which makes REI possible and practical for most centers.
2.4. Statistical analysis Statistical analysis was performed using R (version 3.3.3, R Core Team 2017, Vienna, Austria). Data are presented as the median with the interquartile range (IQR) and 95% confidence intervals (95% CI), unless otherwise specified. The distribution of variables was investigated for normality using the one-sample Kolmogorov-Smirnov test. Chisquared and Fisher's exact probability tests were performed for categorical variables. Student's t-test was performed for continuous variables. A p-value less than 0.05 was considered statistically significant. 3. Results 3.1. Intubation outcomes REI was successfully performed in 15 infants. One intubation attempt was sufficient using this technique. The intubations were assisted using the 0° endoscope in 11 cases, the 30° endoscope in 1 case, and the 70° endoscope in 3 cases. The duration of intubation for the REI group was 66.5 s (IQR 58–74, 95% CI 59.8–72.2). Since fewer attempts were required and no repeated mask ventilation was necessary, the total anesthetic preparation duration was 6 min in the REI group (IQR 5–7, 95%CI 5.2–8.0), which was shorter than in patients intubated using conventional technique (15 min, IQR 10–20, 95% CI 12.7–20.7, p < 0.001). No volume reduction of cysts or tracheotomies were performed, and no cysts were ruptured nor did laryngeal mucosal damage occur in the REI group. In the conventional group, 1 patient required a tracheotomy, and 4 required cyst volume reduction by needle aspiration. 64
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Fig. 4. Endoscopic view before and after surgical resection. Vallecular cysts can deform the epiglottis (E) and the surrounding mucosa. When viewed with the naked eye, these anatomical structures can be confused and lead an intubation failure.
Table 2 Different device for intubation. Products
Features
Drawbacks
Flexible Fibroscope STORZ intubation fibroscope Light-stylets AincA
Suitable for ETT 2.5–3.5 mm
Poor image
Suitable for ETT 2.5 mm or larger
Problem of blurred scope; No suction
Videolaryngoscope STORZ C-MAC VLS
Operational with smallest mouth opening (blade height 5 mm)
Glidescope
Large field of vision (full view of glottis and surroundings)
Airtraq Truview PCD
Good view of glottis and near surrounding With oxygen insufflation
Limited field of vision (only glottis); No anti-fog mechanism Lager size (blade height 10 mm); Problem of blurred scope by saliva Bulky for narrow airways (blade height 12 mm) Lager size (blade height 8 mm); Limited field of vision (only glottis)
ETT, endotracheal tube.
Flexible fiberscopes, light-stylets, or glidescopes can also provide better visualization of the glottis in cases with difficult upper airways [16–18], but these instruments have some limitations in very young patients (Table 2) [19,20]. Flexible fiberscopes or light-stylets are generally used by mounting an ETT and then guiding it into the trachea, but ETT for neonates is too narrow to be mounted. Additionally, visualization of the glottis using a flexible fiberscope or light-stylet can easily be blurred by saliva and/or body fluids because these instruments lack a suction cannula. A flexible suction tube can be used in this situation but has limited benefits. A rigid endoscope, however, can accommodate any size of ETT and allows for the concurrent use of a suction tube, flexible or rigid, to provide a
clearer view. A good view of the laryngeal anatomy is necessary for quick and successful intubation. Sometimes, vallecular cysts deform the surrounding mucosa and can cause it to resemble the epiglottis (Fig. 4), which may be the main reason for the failure of intubation attempts made with the naked eye or a blurred scope. Glidescopes and video laryngoscopes have a built-in camera on their blades; therefore, the movement of the camera is limited by the blade, particularly in narrower pharyngolaryngeal spaces caused by poor body growth. Sometimes, forceful movements can damage the soft tissues in the pharynx or larynx and can make the surgical area difficult to visualize. Under endoscopic-assisted intubation, the field of vision under the rigid endoscope is free and directly adjustable. Furthermore, angled
Fig. 5. Laryngeal view with a 0° (A) and a 70° (B) endoscope. A 70° angled endoscope (B) can provide better visualization of the glottis in cases with massive vallecular cysts, which can make intubation more precise but requires more practice for use.
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References
endoscopes can be used to achieve better exposure of the glottis, but manipulation of angled endoscopes should be conducted only by welltrained individuals to avoid damaging the mucosa of the posterior pharyngeal wall. In this series, 30° or 70° endoscopes were used in 4 patients with a C-L Grade of 4 to best visualize the glottis (Fig. 5). Another rigid endoscope-assisted intubation technique was reported by Michaelson, also called Seldinger technique, which can be performed by one person [21]. Similarly, this technique uses a direct laryngoscope to expose the glottis, but the ETT is loaded onto the rigid endoscope; then the ETT loaded-endoscope is advanced through the glottis in order to achieve an intubation as using a light-sylet. Before this study, we had used this technique in some cases, but the limitation of the size of ETT was inevitable. Some infants with vallecular cyst were emaciated, such as premature infants or low birth weight infants. Only 2.5 or 3 mm ETT was suitable for them and could not be loaded on the regular endoscope (even the 2.7 mm one). Additionally, we prefer use a bigger endoscope (4 mm), which provides better image and possess a surely rigidity, because the fine endoscope (such as 2.7 mm or smaller) with more than 16 cm-length (the length of 3 mm ETT is about 16 cm) seems to be bent and deteriorated more easily. Furthermore, a suction tube is frequently necessary to remove local mucus and liquid, and it is helpful to push or drag the epiglottis when laryngomalacia associated. Above all, we finally decided to perform the REI technique by two persons with skilled and tacit collaboration.
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5. Conclusion While advanced intubation instruments with narrower sizes have become available in recent years, these instruments are not routinely used in medical centers, likely due to their expense, and have limited availability in developing countries. However, rigid endoscopy systems are commonly equipped in otolaryngology surgical suites worldwide, and otolaryngology surgeons who perform vallecular cyst surgery are commonly skilled in the usage of this instrument. Therefore, REI is an easily applicable technique and quick solution for intubation of neonates or infants with vallecular cysts in medical centers in developing countries. Fundings This work was supported by grants from advanced and appropriate technology promotion projects of the Shanghai Health System (2013SY025), projects of the Shanghai Science and Technology Committee (16XD1402200) and grants of the Key Laboratory (14DZ2260300). Declarations of interest None. Acknowledgements We gratefully acknowledge the figure drawing by Fangfang Wang.
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Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Rigid endoscope-assisted orotracheal intubation for vallecular cyst surgery in neonates and young infants
T
Haoyue Tana,c,e,f,1, Qi Huangc,1, Antoine Paula,c,1, Wei Wangd, Jingjie Lib,d,∗∗, Huan Jiaa,c,e,f,∗ a
Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, No.639 Zhizaoju Road, Shanghai, 200011, China b Anesthesiology Department, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639 Zhizaoju Road, Shanghai, 200011, China c Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1665 Kongjiang Road, Shanghai, 200092, China d Anesthesiology Department, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China e Ear Institute, Shanghai Jiaotong University School of Medicine, No. 390 Yanqiao Road, Shanghai, 200125, China f Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, No. 390 Yanqiao Road, Shanghai, 200125, China
A R T I C LE I N FO
A B S T R A C T
Keywords: Intubation Endoscopes Laryngeal diseases Infant newborn Surgery Airway management
Objectives: To investigate the outcomes of rigid endoscope-assisted orotracheal intubation (REI) in neonates and young infants with difficult airway conditions as an alternative intubation technique when more specific airway instruments are not available in most developing countries, and to evaluate the safety and advantages of this method. Methods: Neonatal and young infantile patients undergoing vallecular cyst surgery with a Cormack-Lehane Grade 3 or 4 glottic view between June 2013 and June 2015 were studied. Fifteen patients were intubated using rigid endoscopic assistance. Fifteen other patients who were intubated using the conventional technique were selected from the previous consecutive cases and used as a matched control group. Results: REI was successfully performed in all 15 patients in one intubation attempt. The anesthetic preparation duration for the REI group was 6 min (interquartile range 5–7 min), which was shorter than the anesthetic preparation duration for patients intubated using the conventional technique (15 min [interquartile range 10–20 min], p < 0.001). The time required for intubation with a rigid endoscope was 66.5 s (interquartile range 58–74 s). No volume reduction of cysts or tracheotomies was needed in the REI group, and no cysts were ruptured nor did laryngeal mucosa damage occur with this technique. Among patients of conventional group, one required a tracheotomy, and four required cyst volume reduction by needle aspiration. No residual lesions or recurrence were observed during one year of postoperative follow-up in the REI group, and two recurrences were observed in the conventional group. Conclusion: REI, which used common pieces of equipment in an otolaryngology operating room, may be a safe and feasible alternative for intubation in neonatal and young infantile patients with vallecular cysts or other difficult airway conditions.
1. Introduction
death. An elective operation during the first few months of life is necessary. However, anesthetic management of the upper airways of these patients can present a great challenge because their laryngeal morphologies (e.g., supraglottic location of cysts, small laryngeal cavities, etc.) make glottic exposure much more difficult [3–5]. In addition, these patients have usually suffered from respiratory distress for several days or weeks, which results in poor compensation capacity for anoxia;
Vallecular cysts are ductal cysts caused by mucus retention at the tongue base due to obstruction of the collecting ducts. The prevalence of vallecular cysts ranges from 1.82 to 5.3 cases per 100,000 live births [1,2]. Cysts present as airway obstruction or feeding difficulty in the neonatal population and can progressively lead to failure-to-thrive or
∗
Corresponding author. Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, No 639 Zhizaoju Road, Shanghai 200011, China. Corresponding author. Anesthesiology Department, Shanghai Ninth People's Hospital, No 639 Zhizaoju Road, Shanghai 200011, China. E-mail addresses: [email protected] (H. Tan), [email protected] (Q. Huang), [email protected] (A. Paul), [email protected] (W. Wang), [email protected] (J. Li), [email protected] (H. Jia). 1 Haoyue TAN, Qi HUANG and Antoine PAUL contributed equally to this work. ∗∗
https://doi.org/10.1016/j.ijporl.2018.04.023 Received 9 March 2018; Received in revised form 16 April 2018; Accepted 19 April 2018 Available online 25 April 2018 0165-5876/ © 2018 Elsevier B.V. All rights reserved.
International Journal of Pediatric Otorhinolaryngology 110 (2018) 61–66
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Fig. 1. MRI T2-weighted axial (A) and coronal (B) views. MRI revealed a cystic mass on the epiglottic vallecula and that the upper airway was narrowed. T, tumor; H, hypopharynx; E, epiglottis.
(the maximum diameter in coronal, sagittal or transverse planes) were also collected (Fig. 1). Ethical approval for this study was provided by the Ethical Committee of Xinhua Hospital, which is affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China. Due to the difficulty and high risk of intubating infants with upper airway obstructions, conventional intubation was not performed after the first successful case was intubated using rigid endoscopic assistance. For comparison, a matched control group was selected from previous consecutive patients who underwent conventional intubation during the similar time frame (seventeen months) (Table 1). The criteria for the control group were as follows: patients were treated by the same medical team (senior surgeon and senior anesthetist); were less than one year of age; and had complete medical records.
therefore, temporary hypoxemia occurs more frequently during intubation, and patients recover slowly with oxygen. All of these factors make intubation of these patients a difficult and high-risk procedure. In the past, blind intubation by a senior anesthetist [6,7] or intubation after volume reduction of cysts [8–10] was performed commonly for these cases; however, these methods can induce laryngeal mucosal damage or cyst deformation and increase the difficulty of surgical resection [1,11]. Intubation performed with rigid endoscopic assistance has been reported in difficult cases of adult patients with epiglottic cysts [12] and in infants with Pierre-Robin syndrome [13]. This method had some advantages and is convenient in cases in which more specific advanced instruments are not available, generally in developing countries. Since June 2013, we have used rigid endoscopicassisted orotracheal intubation (REI) in neonates and young infants with a Cormack-Lehane (C-L) Grade 3 or 4 glottic view. This article aims to present the outcomes of this technique in these difficult airway conditions, to evaluate its safety and advantages, and to compare it with other techniques.
2.2. Endoscope system Endoscopic visualization was achieved using a general rigid otolaryngology endoscope system (Karl Storz GmbH and Co. KG, Tuttlingen, Germany) including 0°, 30° or 70° angled endoscopes (4 mm in diameter and 175 mm in length). The 0° endoscope was used first, and the 30° or 70° angled endoscopes were substituted if the glottis could not be clearly exposed. This system was also subsequently used for the surgical resection of the vallecular cysts.
2. Materials and methods 2.1. Patients Fifteen consecutive neonatal and infant patients with symptomatic vallecular cysts between June 2013 and June 2015, who were intubated using rigid endoscopic assistance, were included in the study. The transoral microsurgeries used to treat these patients' vallecular cysts were performed by the same medical team. The surgical records, discharge summaries, anesthetic records and follow-up records were collected. When available, the radiologic reports regarding the cysts sizes
2.3. Intubation procedures The airway conditions of all patients were evaluated prior to surgery, and their glottic views were assigned a C-L Grade [14]. The steps in the standard procedure for orotracheal intubation using endoscopic video visualization were as follows:
Table 1 Comparison between two techniques. Intubation technique
Case (n)
Age at Surgery (days, median, [IQR])
Sex
Cyst Size (cm, median, [IQR])
CormackLehane grading
Anesthetic preparation duration (min, median, [IQR])
Intubation duration (second, median, [IQR])
Intubation attempt (n, median, [IQR])
Volume reduction (n)
Tracheotomy (n)
Residual after 1 year (n)
REI
15
1 [0.95–1.5]a 1 [0.88–1.5]
66.5 [58.5–74.5] N/Ab
0
4
1
4
0.636
–
1 [1-1] 3 [2–3] < 0.001
0
3–4
6 [5–7] 15 [10–20] < 0.001
0
15
10 Male 5 Female 8 Male 7 Female –
3–4
Conventional technique p-value
60 [34–70] 56 [40–80] 0.881
–
–
–
–
IQR = interquartile range. REI = rigid endoscope-assisted orotracheal intubation. a 13 cases with datas of images were included. b no datas for the cases of conventional technique. 62
–
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2.3.2. Intubation period The otolaryngology surgeon stretched the mouth and pushed the tongue base up using a direct laryngoscope (Seward blade) in his left hand, then held and guided the endoscope gently but quickly with the other hand to expose the glottis. If the glottis could not be exposed well using the 0° endoscope, the 30° or 70° angled endoscope was quickly substituted. All laryngeal structures, including the epiglottis and arytenoid region, were in the endoscopic view for ease of tube insertion. Finally, the anesthetist introduced the endotracheal tube (ETT) into the hypopharyngeal cavity using the naked eye until the tips of the tube were visible on the screen, and then the tube was advanced into the trachea via video visualization (Fig. 2 and Fig. 3). If oxyhemoglobin desaturation progressively decreased to below 70%, mask ventilation with pure oxygen was administered immediately at any period during the previously described steps.
2.3.1. Induction period (pre-intubation) Patients were premedicated with atropine (0.1 mg kg−1) and dexamethasone (0.3 mg kg−1) by intravenous injection. General anesthesia was induced via inhalation of 8% sevoflurane associated with 100% oxygen at a flow rate of 5–6 L min−1, without the use of a muscle relaxant. An injection of dexmedetomidine at a dose of 2 μg kg−1 over 10 min was administered, followed by a continuous infusion at 0.4 μg kg−1 h−1 until the end of the surgery. When the patient became unconscious, the inhaled sevoflurane concentration was reduced to 4–6% based on the respiratory frequency. The tidal volume was maintained for at least 5 min to allow adequate time for alveolar and brain sevoflurane partial pressures to equilibrate before exposing the larynx. This is consistent with a previous report that stated that the minimum alveolar concentration for endotracheal intubation (MACEI) value for sevoflurane in infants of 1–6 months of age was 3.2–3.3% [5]. Lidocaine (2–4%) was applied topically around the larynx with a sprayer, sometimes blindly. The maximum dose of topical lidocaine anesthesia was 4 mg kg−1.
2.3.3. Operation period (post-intubation period) After intubation, remifentanil at a flow rate of 0.05 μg kg−1 minute−1 and propofol at a flow rate of 8–10 mg kg−1 h−1 were used
Fig. 2. Views and steps for glottis exposure using a standard rigid endoscope. A. Visualization when the lens was at the level of the lips, similar to the view using a direct laryngoscope. The vallecular cyst can be seen, but the epiglottis cannot. B. With advancement of the endoscope to the hypopharynx, the epiglottis can be visualized. C. After adjusting the lens, the glottis can be located, and intubation can be assisted. 63
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Fig. 3. Posture for rigid endoscopic-assisted intubation. The otolaryngologist held the direct laryngoscope in his left hand and the rigid endoscope in his right hand. The anesthetist managed the endotracheal tube insertion. The rigid endoscope and direct laryngoscope could be adjusted at any time to provide a better view for intubation.
3.2. Surgical outcomes
for maintenance anesthesia until the end of surgery.
In this series, the surgeries were performed under favorable conditions, and no surgical complications occurred. No residual lesions or recurrence of cysts were observed during 1 year of postoperative follow-up in the REI group. Two recurrences were observed in the conventional intubation group.
2.3.4. Data collection One additional mask ventilation during the intubation period was noted as one additional intubation attempt. On the anesthetic records, the time at the beginning of induction period and at the end of intubation period was routinely noted, and this interval was considered as the anesthetic preparation duration in this study. In the REI group, the pure duration of intubation could be collected from the recorded endoscopic video.
4. Discussion Infants with vallecular cysts in this study were generally emaciated and thinner than same-aged individuals and commonly had associated laryngomalacia. The median age of our series was at 60 days. Consequently, the space and view for intubation was very limited. Vallecular cysts also deformed and shifted the epiglottis caudally, making the glottis more difficult to visualize (Fig. 4A). Therefore, common techniques for improving glottic exposure [15] (e.g., anteriorlateral neck pressure for moving the vocal folds caudally and ventrally) were not helpful. When visualization of the glottis is difficult, repeated and/or blind intubation attempts are usually performed [6,7], which prolongs the anesthetic duration and provokes secondary mucosal damage and cyst deformities. The unclear field of vision and the incorrect identification of tumor boundaries may make complete resection less accurate [1,11] and may be the main reason for 2 recurrent cases among patients who were intubated using the conventional technique. In our experience, REI provides satisfactory visualization of the glottis and quick intubation. Nevertheless, this technique required at least three hands (one for the endoscope, one for the direct laryngoscope, one for intubation, and another for a suction tube if needed). Therefore, collaboration between otolaryngologists and anesthetists is essential. The direct laryngoscope was used to enlarge the narrow space by opening the mouth and pushing the tongue base anteriorly to allow the rigid endoscope to move freely without damaging the mucosa and to avoid bending of the endoscope, which can result in damage to this equipment. A rigid suction tube was useful for removing local mucus and liquid because it is more easily controlled than a flexible suction tube and can also be used to drag or push the epiglottis if needed. A rigid endoscopic system, a common piece of equipment in otolaryngology surgical suites worldwide, and otolaryngology surgeons are skilled at using it, which makes REI possible and practical for most centers.
2.4. Statistical analysis Statistical analysis was performed using R (version 3.3.3, R Core Team 2017, Vienna, Austria). Data are presented as the median with the interquartile range (IQR) and 95% confidence intervals (95% CI), unless otherwise specified. The distribution of variables was investigated for normality using the one-sample Kolmogorov-Smirnov test. Chisquared and Fisher's exact probability tests were performed for categorical variables. Student's t-test was performed for continuous variables. A p-value less than 0.05 was considered statistically significant. 3. Results 3.1. Intubation outcomes REI was successfully performed in 15 infants. One intubation attempt was sufficient using this technique. The intubations were assisted using the 0° endoscope in 11 cases, the 30° endoscope in 1 case, and the 70° endoscope in 3 cases. The duration of intubation for the REI group was 66.5 s (IQR 58–74, 95% CI 59.8–72.2). Since fewer attempts were required and no repeated mask ventilation was necessary, the total anesthetic preparation duration was 6 min in the REI group (IQR 5–7, 95%CI 5.2–8.0), which was shorter than in patients intubated using conventional technique (15 min, IQR 10–20, 95% CI 12.7–20.7, p < 0.001). No volume reduction of cysts or tracheotomies were performed, and no cysts were ruptured nor did laryngeal mucosal damage occur in the REI group. In the conventional group, 1 patient required a tracheotomy, and 4 required cyst volume reduction by needle aspiration. 64
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Fig. 4. Endoscopic view before and after surgical resection. Vallecular cysts can deform the epiglottis (E) and the surrounding mucosa. When viewed with the naked eye, these anatomical structures can be confused and lead an intubation failure.
Table 2 Different device for intubation. Products
Features
Drawbacks
Flexible Fibroscope STORZ intubation fibroscope Light-stylets AincA
Suitable for ETT 2.5–3.5 mm
Poor image
Suitable for ETT 2.5 mm or larger
Problem of blurred scope; No suction
Videolaryngoscope STORZ C-MAC VLS
Operational with smallest mouth opening (blade height 5 mm)
Glidescope
Large field of vision (full view of glottis and surroundings)
Airtraq Truview PCD
Good view of glottis and near surrounding With oxygen insufflation
Limited field of vision (only glottis); No anti-fog mechanism Lager size (blade height 10 mm); Problem of blurred scope by saliva Bulky for narrow airways (blade height 12 mm) Lager size (blade height 8 mm); Limited field of vision (only glottis)
ETT, endotracheal tube.
Flexible fiberscopes, light-stylets, or glidescopes can also provide better visualization of the glottis in cases with difficult upper airways [16–18], but these instruments have some limitations in very young patients (Table 2) [19,20]. Flexible fiberscopes or light-stylets are generally used by mounting an ETT and then guiding it into the trachea, but ETT for neonates is too narrow to be mounted. Additionally, visualization of the glottis using a flexible fiberscope or light-stylet can easily be blurred by saliva and/or body fluids because these instruments lack a suction cannula. A flexible suction tube can be used in this situation but has limited benefits. A rigid endoscope, however, can accommodate any size of ETT and allows for the concurrent use of a suction tube, flexible or rigid, to provide a
clearer view. A good view of the laryngeal anatomy is necessary for quick and successful intubation. Sometimes, vallecular cysts deform the surrounding mucosa and can cause it to resemble the epiglottis (Fig. 4), which may be the main reason for the failure of intubation attempts made with the naked eye or a blurred scope. Glidescopes and video laryngoscopes have a built-in camera on their blades; therefore, the movement of the camera is limited by the blade, particularly in narrower pharyngolaryngeal spaces caused by poor body growth. Sometimes, forceful movements can damage the soft tissues in the pharynx or larynx and can make the surgical area difficult to visualize. Under endoscopic-assisted intubation, the field of vision under the rigid endoscope is free and directly adjustable. Furthermore, angled
Fig. 5. Laryngeal view with a 0° (A) and a 70° (B) endoscope. A 70° angled endoscope (B) can provide better visualization of the glottis in cases with massive vallecular cysts, which can make intubation more precise but requires more practice for use.
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References
endoscopes can be used to achieve better exposure of the glottis, but manipulation of angled endoscopes should be conducted only by welltrained individuals to avoid damaging the mucosa of the posterior pharyngeal wall. In this series, 30° or 70° endoscopes were used in 4 patients with a C-L Grade of 4 to best visualize the glottis (Fig. 5). Another rigid endoscope-assisted intubation technique was reported by Michaelson, also called Seldinger technique, which can be performed by one person [21]. Similarly, this technique uses a direct laryngoscope to expose the glottis, but the ETT is loaded onto the rigid endoscope; then the ETT loaded-endoscope is advanced through the glottis in order to achieve an intubation as using a light-sylet. Before this study, we had used this technique in some cases, but the limitation of the size of ETT was inevitable. Some infants with vallecular cyst were emaciated, such as premature infants or low birth weight infants. Only 2.5 or 3 mm ETT was suitable for them and could not be loaded on the regular endoscope (even the 2.7 mm one). Additionally, we prefer use a bigger endoscope (4 mm), which provides better image and possess a surely rigidity, because the fine endoscope (such as 2.7 mm or smaller) with more than 16 cm-length (the length of 3 mm ETT is about 16 cm) seems to be bent and deteriorated more easily. Furthermore, a suction tube is frequently necessary to remove local mucus and liquid, and it is helpful to push or drag the epiglottis when laryngomalacia associated. Above all, we finally decided to perform the REI technique by two persons with skilled and tacit collaboration.
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5. Conclusion While advanced intubation instruments with narrower sizes have become available in recent years, these instruments are not routinely used in medical centers, likely due to their expense, and have limited availability in developing countries. However, rigid endoscopy systems are commonly equipped in otolaryngology surgical suites worldwide, and otolaryngology surgeons who perform vallecular cyst surgery are commonly skilled in the usage of this instrument. Therefore, REI is an easily applicable technique and quick solution for intubation of neonates or infants with vallecular cysts in medical centers in developing countries. Fundings This work was supported by grants from advanced and appropriate technology promotion projects of the Shanghai Health System (2013SY025), projects of the Shanghai Science and Technology Committee (16XD1402200) and grants of the Key Laboratory (14DZ2260300). Declarations of interest None. Acknowledgements We gratefully acknowledge the figure drawing by Fangfang Wang.
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