- Email: [email protected]
Video RIFL: a rigid flexible laryngoscope to facilitate airway management
Journal of Clinical Anesthesia (2010) 22, 642–647
Case report
Video RIFL: a rigid flexible laryngoscope to facilitate airway management☆ Harsha Setty MD, MSE (Resident)⁎, Joseph L. Rawlings MD (Resident), Stevin Dubin MD (Associate Professor) Department of Anesthesiology and Perioperative Medicine, Medical College of Georgia, Augusta, GA 30912, USA Received 29 May 2009; revised 6 October 2009; accepted 11 October 2009
Keywords: Airway management; Stylet laryngoscope; Upright intubation; Video RIFL (rigid flexible laryngoscope)
Abstract The video RIFL (rigid flexible laryngoscope) is an airway management adjunct designed to facilitate endotracheal intubation. It is a novel stylet-based laryngoscope that incorporates a complementary metal oxide sensor distal chip imaging system and real-time articulation tip. The device combines features desired in fiberoptic bronchoscopy as well as in video laryngoscopy . Four cases involving its use in difficult airway management are presented. © 2010 Elsevier Inc. All rights reserved.
1. Introduction The video RIFL (rigid flexible laryngoscope) is an airway management adjunct designed to facilitate endotracheal intubation. Manufactured by AI Medical Devices, Inc., Williamston, MI, (http://www.aimedicaldevices.com), the video RIFL was registered with the Food and Drug Administration in 2008. It is a novel stylet-based laryngoscope that incorporates a complementary metal oxide semiconductor distal chip imaging system with native qVGA resolution. The handle features both a portable inline liquid crystal display and self-contained power supply in addition to a lever that controls flexion of the distal tip with endotracheal tube (ETT) up to 135°, as shown in Fig. 1. The ☆ Disclosure: Dr. Setty is co-developer of the video RIFL® and has received compensation from the manufacturer, AI Medical Devices, Williamston, MI (http://www.aimedicaldevices.com). The other authors of this manuscript and the Department of Anesthesiology at Medical College of Georgia receive no financial support and do not have any commercial relationships with the device manufacturer. ⁎ Corresponding author. Tel.: +1 706 721 3871. E-mail address: [email protected] (H. Setty).
0952-8180/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2009.10.019
handle also has integrated composite video output access for use with an external recording device or monitor. The realtime articulating distal tip is composed of a durable articulating alloy and features stainless steel housing for the imaging system. Overall, the device combines features desired in flexible fiberoptic bronchoscopy as well as video laryngoscopy.
2. Case report 2.1. Case 1 A 51 year-old, 170 kg, 180 cm man sustained left femur and right distal radius fractures in a motor vehicle accident. He had an external fixator on the left leg and sling for the right arm, and support by an adult short collar since he was not cleared for cervical spine injury. In addition to the recent trauma, his other significant medical problems included morbid obesity, diabetes, and hypertension. Airway assessment showed a short immobilized neck, hyomental distance b 3.0 cm, and a Mallampati 3 airway.
Video RIFL® in airway management
643
Fig. 1 Video RIFL (AI Medical Devices, Inc., Williamston, MI, USA) extended (L) and flexed (R).
Consequently, intubation was anticipated to be difficult. The patient's head was maintained in neutral position with a stack of towels placed underneath each shoulder to help align the laryngeal, pharyngeal, and oral axes [1]. Anesthesia induction took place on the stretcher due to the patient's limited mobility. The anterior portion of the collar was loosened to allow facemask ventilation. He was pre-medicated with midazolam and glycopyrrolate before arrival at the operating room (OR). The patient was induced with etomidate, and mask ventilation was successful with an oral airway in place.
Fig. 2
Neuromuscular relaxation was achieved with succinylcholine. Pre-induction vital signs were blood pressure (BP) 108/74 mmHg, heart rate (HR) 112 beats per minute (bpm), and oxygen saturation (SpO2) 100%. A wooden tongue depressor displaced the tongue to allow insertion of the curved RIFL blade, as shown in Fig. 2. The RIFL blade is a modified polycarbonate tongue blade equipped with an integrated channel to allow passage of the video RIFL and ETT. When the video RIFL was inserted into the mouth the inter-incisor distance required was less than 3.0 cm to allow passage of the ETT along the curved blade. No extension of the neck or manual inline stabization was applied to the patient, and oral secretions were not present during visualization. The RIFL blade allowed easy passage of the RIFL scope loaded with a 7.5 mm internal diameter (ID) ETT. Flexion of the scope tip enabled equivalent Grade I visualization of the vocal cords and glottic opening. The ETT was placed into the trachea, with total time from scope insertion into the mouth to ETT insertion into the glottis of approximately 20 seconds. Hemodynamic parameters inclusive of HR, SpO2, and BP were not significantly elevated post-intubation compared with pre-intubation. The cervical collar was reattached post-intubation after the ETT was adequately secured, and ventilation with end-tidal CO2 (ETCO2) waveforms and auscultation of bilateral breath sounds were confirmed.
2.2. Case 2 A 56 year-old, 93 kg, 160 cm woman presented for exploration of lumbar spinal fusion. Her medical history was significant for severe back pain caused by severe
Curved RIFL blade (L) and in-use (R).
644
H. Setty et al. 10 seconds and then returned to pre-intubation values. All other vital signs remained unchanged. Tube position was confirmed by auscultation and ETCO2. The first-year anesthesiology resident who performed the intubation did have experience with both direct laryngoscopy and flexible bronchoscopy.
2.3. Case 3
Fig. 3 Mannequin demonstration of anterior traction with tongue-chin lift.
dextroscoliosis and herniated nucleus pulposus, hypertension, moderate mitral regurgitation, gastroesophageal reflux, and breast cancer status-post-radiation and chemotherapy. Her surgical history included multilevel anterior cervical decompression and fusion, subsequent posterior exploration, as well as C2-T4 laminectomy and arthrodesis. Her airway was Mallampati class 1 with adequate oral opening and hyomental distance; however, she had significantly limited neck motion secondary to prior cervical instrumentation. Neutral neck position for this patient was approximately 10° to 20°, with severely limited extension. Given her history of gastroesophageal reflux, rapidsequence induction with cricoid pressure was elected with induction on the stretcher prior to prone repositioning for the procedure. Due to her severe discomfort and anatomical limitation, the head of the stretcher was elevated 20° and 4 folded towels were placed under her head. This action maintained her head in the neutral position, slightly flexed, for the duration of intubation. After adequate preoxygenation, she underwent anesthesia induction with fentanyl, propofol, and succinylcholine. Cricoid pressure was maintained. Baseline vital signs were BP 121/61 mmHg, HR 71 bpm, and SpO2 100%. After it was loaded with a 7.0 mm ID standard ETT, the video RIFL was inserted using anterior mandibular displacement by inserting the left thumb into the mouth with fingers on the chin and providing gentle anterior traction [2], as shown in Fig. 3. The video RIFL was advanced, a grade I equivalent view was achieved, and the ETT was placed into the trachea within 20 seconds of mask removal. The patient's HR was elevated by 10 bpm for approximately
A 53 year-old man presented for direct laryngoscopy and biopsy with a recent abnormal positron emission tomographic (PET) scan. In the previous year, he had developed progressive dysphagia for solids followed by odynophagia, and subsequent workup showed an etiology of supraglottic squamous cell carcinoma of the right base of the tongue and vallecula (T3N2M0). The patient had a history of a difficult intubation. Eight months earlier he underwent direct laryngoscopy with biopsy that required nasal fiberoptic intubation after unsuccessful oral attempts using a Macintosh Blade, Miller Blade, GlideScope portable video laryngoscopy (GVL; Verathon, Bothell, WA, USA), and Dido laryngoscope. None of these adjuncts allowed visualization of the vocal cords. The decision was made to place a tracheostomy at the end of this procedure. The patient underwent a second procedure, seven months after tracheostomy, for closure of his tracheocutaneous fistula. He had received radiation therapy in the interim and had a nonhealing tracheocutaneous fistula. During induction, oral intubation was unsuccessfully attempted using a Macintosh blade, Miller blade, portable GVL, and Anterior Commissure Scope. Retrograde intubation was successful using a bougie catheter. The patient's trachea was extubated at the end of this procedure, and he did not require a tracheostomy. He presented to us with a Mallampati class 3 airway with adequate oral opening but short thyromental distance (2.0 cm). His anterior soft tissue was less pliable during this procedure due to radiation therapy.
Fig. 4 View of awake upright intubation prior to endotracheal tube insertion, image output directly from video RIFL.
Video RIFL® in airway management
645
Fig. 5 Views of intubation through a supraglottic airway prior to (L) and during (R) endotracheal tube insertion, image output directly from video RIFL.
The decision was made to use the video RIFL as the primary intubation device in the upright sitting position, with fiberoptic bronchoscopy reserved for backup. The video RIFL was loaded with a 7.0 mm ID Parker Flex Tip ETT (Parker Medical, Bridgewater, CT, USA). While in the upright sitting position, the patient received topical anesthetic with anesthetic inclusive of cetacaine spray, 4% lidocaine mist, lidocaine ointment on nasal trumpets, and lidocaine ointment on a 9 cm oral airway placed in the patient's oropharynx. Fentanyl bolus and low-dose propofol infusion were started prior to scope insertion. Pre-intubation vital signs included BP 136/80 mmHg, HR 88 bpm, respiratory rate (RR) 10 breaths per minute (breaths/min), and SpO2 100%. Video RIFL insertion was performed by a junior resident, an equivalent grade 1 view was obtained, and the ETT was seen passing through the vocal cords. The patient's anatomy indicated that the true vocal cords were recessed relative to the aretynoids (Fig. 4). The overall intubation was atraumatic. He was awake and compliant with the entire procedure, and post-intubation vital signs were HR 96 bpm, BP 128/76 mmHg, RR 12 breaths/min, and SpO2 100%.
distance N three finger widths, oral opening N 3.0 cm, and a Mallampati class 3 airway. Managing her airway was anticipated to be challenging due to her habitus. Her head was maintained in neutral position with a stack of towels placed underneath each shoulder to help align the laryngeal, pharyngeal, and oral axes [1]. The patient received midazolam prior to arrival at the OR. Induction with propofol was followed by insertion of a 3.5 Air-Q supraglottic airway (SGA; Mercury Medical, Clearwater, FL, USA). A seal to 20 cm H2O was achieved. The video RIFL was loaded with a 6.5 mm ID standard ETT and inserted through the inner lumen of the SGA after ventilation on sevoflurane for less than three minutes. Prior to insertion into the SGA, the outer lumen of the ETT was lubricated with aqueous gel to facilitate passage. The rigid shaft of the video RIFL allowed passage of the ETT through the SGA; articulation of the distal tip enabled advancement of the ETT under direct visualization (Fig. 5). The intubation required no use of neuromuscular blocking agents. The SGA was removed over the ETT after the ETT was disconnected from the ventilation circuit, and holding a stabilizing rod to maintain positioning of the ETT.
2.4. Case 4
3. Discussion A 75 year-old, 95 kg, 162 cm woman presented for right total knee replacement secondary to severe osteoarthritis. Her airway assessment showed a short neck, hyomental
Fig. 6
Video laryngoscopy has improved the ability of clinicians to perform endotracheal intubation. It moves the visual focal
Direct alignment of optical (dash) and geometric (red) axes, as seen in direct laryngoscopy and stylet based adjuncts.
646
H. Setty et al.
Fig. 7
Indirect alignment of optical (dash) and geometric (red) axes, as seen in video laryngoscopy.
point closer to the vocal cords, increasing magnification of the working area, and allowing others to observe the process. Technological trends facilitated transition from first-generation video laryngoscopes to solid-state sensors (ie, complementary metal oxide semiconductor). The predominant gold standard is fiberoptic bronchoscopy, offering multiple degrees of articulation but lacking both stylet rigidity and capability of articulating an ETT. However, preformed stylets offer stability for ETT placement but lack articulation. Real-time tip articulation allows accommodation for anatomical variations to avoid time-intensive repositioning and readjusting of malleable stylets during intubation, as well as additional trauma associated with increasing lifting force with blade adjuncts. The video RIFL is currently the only commercially available stylet-based video laryngoscope that offers realtime articulation of the ETT. The original Cormack-Lehane grading scale [3] relied on direct laryngoscopy, and alignment of both the optical and geometric axes provided a realistic assessment of difficulty of placing an ETT for airway management. The optical axis refers to the line of sight between the target and sensor, and the geometric axis refers to uninterrupted free-space
Fig. 8
between the target and sensor, along which the hand or ETT may move. Conventional video laryngoscopes (ie, GVL [4], McGrath (LMA North America, Inc., San Diego, CA, USA) [5], Storz DCI (Karl Storz GmbH & Co. KG, Tuttlingen, Germany) [6]) all provide Cormack-Lehane equivalent views (Grades I-IV) but the discontinuity between the optical and geometric axis does not indicate difficulty placing an ETT. In extreme cases, the practitioner is given a false sense of the true difficulty of ETT placement, particularly since advancement of the ETT is often performed blindly while the optical sensor is focused on the vocal cords. Additional effort is required to place an ETT into the mouth and navigate towards the glottic opening, and blind navigation may increase the risk of soft-tissue damage [7-9]. The additional complexity of not aligning the geometric and optical axes is readily seen with laparoscopic surgery, where the surgeon focuses on the output monitor and manipulates surgical tools with working ends outside the direct line of sight. Optical stylet laryngoscopes (ie, Shikani optical stylet (SOS; Clarus Medical LLC, Minneapolis, MN, USA) [2], Video RIFL, and the Bonfils retromolar (Karl Storz) [10]) maintain alignment of the optical and geometric axes and
Alignment of optical and geometric axes in Case #1, as seen with video RIFL before intubation (R) and during (L) intubation.
Video RIFL® in airway management would be more reliable in placing an ETT when a sufficient view is obtained. There is no discontinuity between optical and geometric axes when using optical stylets since the view to the user is the same trajectory as the ETT. The end user needs only to create a working space to obtain a view with a video stylet for ETT placement using a Macintosh Laryngoscope, by anterior mandibular displacement or hollow oral airway. There is less potential trauma with direct placement since ETT advancement around soft tissue is performed with direct visualization; however, there is a known risk of pharyngeal trauma and throat soreness with direct laryngoscopy [10]. Figs. 6-8 show the alignment of optical and geometric axes between the stylet and non-stylet based laryngoscopes.
4. Summary A rigid device with articulation allows reliable navigation around soft tissue, particularly the epiglottis. The minimal preparation of the video RIFL relative to a fiberoptic bronchoscope makes it a valuable adjunct for the unanticipated difficult airway. The video RIFL served as a valuable device in a difficult airway where prior intubation attempts were unsuccessful with the Macintosh, Miller, video laryngoscope, Dido laryngoscope, and Anterior Commissure Scope. The device also served as a useful adjunct for intubation through an SGA; the video RIFL may rapidly assist in securing an airway with an ETT when a patient's lungs may be ventilated only with an in-situ SGA. The video RIFL requires less manipulation of patient positioning, and a sole provider was able to use it for intubation without assistance with manual inline stabiliza-
647 tion or other maneuvers. The lack of high-force direct laryngoscopy reduces sympathetic stimulation and significantly reduces the risk of oral trauma [10]. Although there is a learning curve associated with real-time articulation, mastering this feature requires minimal training and practice.
References [1] Stone D, Gal T. Airway management. In: Stoelting RK, Miller RD, editors. Basics of Anesthesia. 5th edn. Philadelphia: Churchill Livingstone; 2000. p. 1414-51. [2] Shikani AH. A new “seeing” stylet-scope and method for the management of the difficult airway. Otolaryngol Head Neck Surg 1999;120:113-6. [3] Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984;39:1105-11. [4] Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth 2005;52:191-8. [5] Shippey B, Ray D, McKeown D. Case series: the McGrath videolaryngoscope–an initial clinical evaluation. Can J Anaesth 2007;54:307-13. [6] Cavus E, Kieckhaefer J, Doerges V, Moeller T, Thee C, Wagner K. The C-MAC videolaryngoscope: first experiences with a new device for videolaryngoscopy-guided intubation. Anesth Analg 2010;110: 473-7. [7] Hsu WT, Hsu SC, Lee YL, Huang JS, Chen CL. Penetrating injury of the soft palate during GlideScope intubation. Anesth Analg 2007;104: 1609-10. [8] Williams D, Ball DR. Palatal perforation associated with McGrath videolaryngoscope. Anaesthesia 2009;64:1144-5. [9] Malik AM, Frogel JK. Anterior tonsillar pillar perforation during GlideScope video laryngoscopy. Anesth Analg 2007;104:1610-1. [10] Liem EB, Bjoraker DG, Gravenstein D. New options for airway management: intubating fibreoptic stylets. Br J Anaesth 2003;91: 408-18.
Case report
Video RIFL: a rigid flexible laryngoscope to facilitate airway management☆ Harsha Setty MD, MSE (Resident)⁎, Joseph L. Rawlings MD (Resident), Stevin Dubin MD (Associate Professor) Department of Anesthesiology and Perioperative Medicine, Medical College of Georgia, Augusta, GA 30912, USA Received 29 May 2009; revised 6 October 2009; accepted 11 October 2009
Keywords: Airway management; Stylet laryngoscope; Upright intubation; Video RIFL (rigid flexible laryngoscope)
Abstract The video RIFL (rigid flexible laryngoscope) is an airway management adjunct designed to facilitate endotracheal intubation. It is a novel stylet-based laryngoscope that incorporates a complementary metal oxide sensor distal chip imaging system and real-time articulation tip. The device combines features desired in fiberoptic bronchoscopy as well as in video laryngoscopy . Four cases involving its use in difficult airway management are presented. © 2010 Elsevier Inc. All rights reserved.
1. Introduction The video RIFL (rigid flexible laryngoscope) is an airway management adjunct designed to facilitate endotracheal intubation. Manufactured by AI Medical Devices, Inc., Williamston, MI, (http://www.aimedicaldevices.com), the video RIFL was registered with the Food and Drug Administration in 2008. It is a novel stylet-based laryngoscope that incorporates a complementary metal oxide semiconductor distal chip imaging system with native qVGA resolution. The handle features both a portable inline liquid crystal display and self-contained power supply in addition to a lever that controls flexion of the distal tip with endotracheal tube (ETT) up to 135°, as shown in Fig. 1. The ☆ Disclosure: Dr. Setty is co-developer of the video RIFL® and has received compensation from the manufacturer, AI Medical Devices, Williamston, MI (http://www.aimedicaldevices.com). The other authors of this manuscript and the Department of Anesthesiology at Medical College of Georgia receive no financial support and do not have any commercial relationships with the device manufacturer. ⁎ Corresponding author. Tel.: +1 706 721 3871. E-mail address: [email protected] (H. Setty).
0952-8180/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2009.10.019
handle also has integrated composite video output access for use with an external recording device or monitor. The realtime articulating distal tip is composed of a durable articulating alloy and features stainless steel housing for the imaging system. Overall, the device combines features desired in flexible fiberoptic bronchoscopy as well as video laryngoscopy.
2. Case report 2.1. Case 1 A 51 year-old, 170 kg, 180 cm man sustained left femur and right distal radius fractures in a motor vehicle accident. He had an external fixator on the left leg and sling for the right arm, and support by an adult short collar since he was not cleared for cervical spine injury. In addition to the recent trauma, his other significant medical problems included morbid obesity, diabetes, and hypertension. Airway assessment showed a short immobilized neck, hyomental distance b 3.0 cm, and a Mallampati 3 airway.
Video RIFL® in airway management
643
Fig. 1 Video RIFL (AI Medical Devices, Inc., Williamston, MI, USA) extended (L) and flexed (R).
Consequently, intubation was anticipated to be difficult. The patient's head was maintained in neutral position with a stack of towels placed underneath each shoulder to help align the laryngeal, pharyngeal, and oral axes [1]. Anesthesia induction took place on the stretcher due to the patient's limited mobility. The anterior portion of the collar was loosened to allow facemask ventilation. He was pre-medicated with midazolam and glycopyrrolate before arrival at the operating room (OR). The patient was induced with etomidate, and mask ventilation was successful with an oral airway in place.
Fig. 2
Neuromuscular relaxation was achieved with succinylcholine. Pre-induction vital signs were blood pressure (BP) 108/74 mmHg, heart rate (HR) 112 beats per minute (bpm), and oxygen saturation (SpO2) 100%. A wooden tongue depressor displaced the tongue to allow insertion of the curved RIFL blade, as shown in Fig. 2. The RIFL blade is a modified polycarbonate tongue blade equipped with an integrated channel to allow passage of the video RIFL and ETT. When the video RIFL was inserted into the mouth the inter-incisor distance required was less than 3.0 cm to allow passage of the ETT along the curved blade. No extension of the neck or manual inline stabization was applied to the patient, and oral secretions were not present during visualization. The RIFL blade allowed easy passage of the RIFL scope loaded with a 7.5 mm internal diameter (ID) ETT. Flexion of the scope tip enabled equivalent Grade I visualization of the vocal cords and glottic opening. The ETT was placed into the trachea, with total time from scope insertion into the mouth to ETT insertion into the glottis of approximately 20 seconds. Hemodynamic parameters inclusive of HR, SpO2, and BP were not significantly elevated post-intubation compared with pre-intubation. The cervical collar was reattached post-intubation after the ETT was adequately secured, and ventilation with end-tidal CO2 (ETCO2) waveforms and auscultation of bilateral breath sounds were confirmed.
2.2. Case 2 A 56 year-old, 93 kg, 160 cm woman presented for exploration of lumbar spinal fusion. Her medical history was significant for severe back pain caused by severe
Curved RIFL blade (L) and in-use (R).
644
H. Setty et al. 10 seconds and then returned to pre-intubation values. All other vital signs remained unchanged. Tube position was confirmed by auscultation and ETCO2. The first-year anesthesiology resident who performed the intubation did have experience with both direct laryngoscopy and flexible bronchoscopy.
2.3. Case 3
Fig. 3 Mannequin demonstration of anterior traction with tongue-chin lift.
dextroscoliosis and herniated nucleus pulposus, hypertension, moderate mitral regurgitation, gastroesophageal reflux, and breast cancer status-post-radiation and chemotherapy. Her surgical history included multilevel anterior cervical decompression and fusion, subsequent posterior exploration, as well as C2-T4 laminectomy and arthrodesis. Her airway was Mallampati class 1 with adequate oral opening and hyomental distance; however, she had significantly limited neck motion secondary to prior cervical instrumentation. Neutral neck position for this patient was approximately 10° to 20°, with severely limited extension. Given her history of gastroesophageal reflux, rapidsequence induction with cricoid pressure was elected with induction on the stretcher prior to prone repositioning for the procedure. Due to her severe discomfort and anatomical limitation, the head of the stretcher was elevated 20° and 4 folded towels were placed under her head. This action maintained her head in the neutral position, slightly flexed, for the duration of intubation. After adequate preoxygenation, she underwent anesthesia induction with fentanyl, propofol, and succinylcholine. Cricoid pressure was maintained. Baseline vital signs were BP 121/61 mmHg, HR 71 bpm, and SpO2 100%. After it was loaded with a 7.0 mm ID standard ETT, the video RIFL was inserted using anterior mandibular displacement by inserting the left thumb into the mouth with fingers on the chin and providing gentle anterior traction [2], as shown in Fig. 3. The video RIFL was advanced, a grade I equivalent view was achieved, and the ETT was placed into the trachea within 20 seconds of mask removal. The patient's HR was elevated by 10 bpm for approximately
A 53 year-old man presented for direct laryngoscopy and biopsy with a recent abnormal positron emission tomographic (PET) scan. In the previous year, he had developed progressive dysphagia for solids followed by odynophagia, and subsequent workup showed an etiology of supraglottic squamous cell carcinoma of the right base of the tongue and vallecula (T3N2M0). The patient had a history of a difficult intubation. Eight months earlier he underwent direct laryngoscopy with biopsy that required nasal fiberoptic intubation after unsuccessful oral attempts using a Macintosh Blade, Miller Blade, GlideScope portable video laryngoscopy (GVL; Verathon, Bothell, WA, USA), and Dido laryngoscope. None of these adjuncts allowed visualization of the vocal cords. The decision was made to place a tracheostomy at the end of this procedure. The patient underwent a second procedure, seven months after tracheostomy, for closure of his tracheocutaneous fistula. He had received radiation therapy in the interim and had a nonhealing tracheocutaneous fistula. During induction, oral intubation was unsuccessfully attempted using a Macintosh blade, Miller blade, portable GVL, and Anterior Commissure Scope. Retrograde intubation was successful using a bougie catheter. The patient's trachea was extubated at the end of this procedure, and he did not require a tracheostomy. He presented to us with a Mallampati class 3 airway with adequate oral opening but short thyromental distance (2.0 cm). His anterior soft tissue was less pliable during this procedure due to radiation therapy.
Fig. 4 View of awake upright intubation prior to endotracheal tube insertion, image output directly from video RIFL.
Video RIFL® in airway management
645
Fig. 5 Views of intubation through a supraglottic airway prior to (L) and during (R) endotracheal tube insertion, image output directly from video RIFL.
The decision was made to use the video RIFL as the primary intubation device in the upright sitting position, with fiberoptic bronchoscopy reserved for backup. The video RIFL was loaded with a 7.0 mm ID Parker Flex Tip ETT (Parker Medical, Bridgewater, CT, USA). While in the upright sitting position, the patient received topical anesthetic with anesthetic inclusive of cetacaine spray, 4% lidocaine mist, lidocaine ointment on nasal trumpets, and lidocaine ointment on a 9 cm oral airway placed in the patient's oropharynx. Fentanyl bolus and low-dose propofol infusion were started prior to scope insertion. Pre-intubation vital signs included BP 136/80 mmHg, HR 88 bpm, respiratory rate (RR) 10 breaths per minute (breaths/min), and SpO2 100%. Video RIFL insertion was performed by a junior resident, an equivalent grade 1 view was obtained, and the ETT was seen passing through the vocal cords. The patient's anatomy indicated that the true vocal cords were recessed relative to the aretynoids (Fig. 4). The overall intubation was atraumatic. He was awake and compliant with the entire procedure, and post-intubation vital signs were HR 96 bpm, BP 128/76 mmHg, RR 12 breaths/min, and SpO2 100%.
distance N three finger widths, oral opening N 3.0 cm, and a Mallampati class 3 airway. Managing her airway was anticipated to be challenging due to her habitus. Her head was maintained in neutral position with a stack of towels placed underneath each shoulder to help align the laryngeal, pharyngeal, and oral axes [1]. The patient received midazolam prior to arrival at the OR. Induction with propofol was followed by insertion of a 3.5 Air-Q supraglottic airway (SGA; Mercury Medical, Clearwater, FL, USA). A seal to 20 cm H2O was achieved. The video RIFL was loaded with a 6.5 mm ID standard ETT and inserted through the inner lumen of the SGA after ventilation on sevoflurane for less than three minutes. Prior to insertion into the SGA, the outer lumen of the ETT was lubricated with aqueous gel to facilitate passage. The rigid shaft of the video RIFL allowed passage of the ETT through the SGA; articulation of the distal tip enabled advancement of the ETT under direct visualization (Fig. 5). The intubation required no use of neuromuscular blocking agents. The SGA was removed over the ETT after the ETT was disconnected from the ventilation circuit, and holding a stabilizing rod to maintain positioning of the ETT.
2.4. Case 4
3. Discussion A 75 year-old, 95 kg, 162 cm woman presented for right total knee replacement secondary to severe osteoarthritis. Her airway assessment showed a short neck, hyomental
Fig. 6
Video laryngoscopy has improved the ability of clinicians to perform endotracheal intubation. It moves the visual focal
Direct alignment of optical (dash) and geometric (red) axes, as seen in direct laryngoscopy and stylet based adjuncts.
646
H. Setty et al.
Fig. 7
Indirect alignment of optical (dash) and geometric (red) axes, as seen in video laryngoscopy.
point closer to the vocal cords, increasing magnification of the working area, and allowing others to observe the process. Technological trends facilitated transition from first-generation video laryngoscopes to solid-state sensors (ie, complementary metal oxide semiconductor). The predominant gold standard is fiberoptic bronchoscopy, offering multiple degrees of articulation but lacking both stylet rigidity and capability of articulating an ETT. However, preformed stylets offer stability for ETT placement but lack articulation. Real-time tip articulation allows accommodation for anatomical variations to avoid time-intensive repositioning and readjusting of malleable stylets during intubation, as well as additional trauma associated with increasing lifting force with blade adjuncts. The video RIFL is currently the only commercially available stylet-based video laryngoscope that offers realtime articulation of the ETT. The original Cormack-Lehane grading scale [3] relied on direct laryngoscopy, and alignment of both the optical and geometric axes provided a realistic assessment of difficulty of placing an ETT for airway management. The optical axis refers to the line of sight between the target and sensor, and the geometric axis refers to uninterrupted free-space
Fig. 8
between the target and sensor, along which the hand or ETT may move. Conventional video laryngoscopes (ie, GVL [4], McGrath (LMA North America, Inc., San Diego, CA, USA) [5], Storz DCI (Karl Storz GmbH & Co. KG, Tuttlingen, Germany) [6]) all provide Cormack-Lehane equivalent views (Grades I-IV) but the discontinuity between the optical and geometric axis does not indicate difficulty placing an ETT. In extreme cases, the practitioner is given a false sense of the true difficulty of ETT placement, particularly since advancement of the ETT is often performed blindly while the optical sensor is focused on the vocal cords. Additional effort is required to place an ETT into the mouth and navigate towards the glottic opening, and blind navigation may increase the risk of soft-tissue damage [7-9]. The additional complexity of not aligning the geometric and optical axes is readily seen with laparoscopic surgery, where the surgeon focuses on the output monitor and manipulates surgical tools with working ends outside the direct line of sight. Optical stylet laryngoscopes (ie, Shikani optical stylet (SOS; Clarus Medical LLC, Minneapolis, MN, USA) [2], Video RIFL, and the Bonfils retromolar (Karl Storz) [10]) maintain alignment of the optical and geometric axes and
Alignment of optical and geometric axes in Case #1, as seen with video RIFL before intubation (R) and during (L) intubation.
Video RIFL® in airway management would be more reliable in placing an ETT when a sufficient view is obtained. There is no discontinuity between optical and geometric axes when using optical stylets since the view to the user is the same trajectory as the ETT. The end user needs only to create a working space to obtain a view with a video stylet for ETT placement using a Macintosh Laryngoscope, by anterior mandibular displacement or hollow oral airway. There is less potential trauma with direct placement since ETT advancement around soft tissue is performed with direct visualization; however, there is a known risk of pharyngeal trauma and throat soreness with direct laryngoscopy [10]. Figs. 6-8 show the alignment of optical and geometric axes between the stylet and non-stylet based laryngoscopes.
4. Summary A rigid device with articulation allows reliable navigation around soft tissue, particularly the epiglottis. The minimal preparation of the video RIFL relative to a fiberoptic bronchoscope makes it a valuable adjunct for the unanticipated difficult airway. The video RIFL served as a valuable device in a difficult airway where prior intubation attempts were unsuccessful with the Macintosh, Miller, video laryngoscope, Dido laryngoscope, and Anterior Commissure Scope. The device also served as a useful adjunct for intubation through an SGA; the video RIFL may rapidly assist in securing an airway with an ETT when a patient's lungs may be ventilated only with an in-situ SGA. The video RIFL requires less manipulation of patient positioning, and a sole provider was able to use it for intubation without assistance with manual inline stabiliza-
647 tion or other maneuvers. The lack of high-force direct laryngoscopy reduces sympathetic stimulation and significantly reduces the risk of oral trauma [10]. Although there is a learning curve associated with real-time articulation, mastering this feature requires minimal training and practice.
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