Palatopharyngeal wall perforation during GlideScope[R] intubation.
We report a case of palatopharyngeal wall perforation during
intubation with a GlideScope[R] laryngoscope. The likely mechanism was
advancing and rotating the endotracheal tube against a taut
palatopharyngeal fold. This was missed during the initial laryngoscopy,
because there is a potential blind-spot in the oropharynx when attention
is focused on the GlideScope[R] monitor. Fortunately, there were no
sequelae other than minor bleeding and a mild sore throat and no
surgical intervention was necessary. The use of unnecessary force during
the endotracheal tube insertion, the use of too large a laryngoscope
blade and the use of a rigid stylet could possibly also have been
contributory factors to this complication.
Key Words: intubation, Glidescope, complications, pharyngeal perforation
|Article Type:||Case study|
Endoscopes (Health aspects)
Gastroscopes (Health aspects)
Uterine cancer (Diagnosis)
Uterine cancer (Care and treatment)
Uterine cancer (Patient outcomes)
Uterine cancer (Case studies)
|Publication:||Name: Anaesthesia and Intensive Care Publisher: Australian Society of Anaesthetists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2008 Australian Society of Anaesthetists ISSN: 0310-057X|
|Issue:||Date: Nov, 2008 Source Volume: 36 Source Issue: 6|
|Product:||Name: GlideScope (Radiological instrument); GlideScope (Radiological instrument) Product Code: 3841260 Endoscopes NAICS Code: 334510 Electromedical and Electrotherapeutic Apparatus Manufacturing SIC Code: 3840 Medical Instruments and Supplies|
|Geographic:||Geographic Scope: Singapore Geographic Code: 9SING Singapore|
The GlideScope[R] Videolaryngoscope (Verathon Medical, Bothell,
Washington, USA) is a new airway device introduced commercially in 2002.
It incorporates a high-resolution camera embedded within the blade and
displays the image on a seven-inch monitor. Intubation using the
GlideScope[R] system allows visualisation of the vocal cords without
alignment of the oral, pharyngeal and tracheal axes (1,2).
Its use is becoming established in cases of anticipated and unanticipated difficult intubation owing to the ease of preparation and setting-up, a relatively short duration to intubation, improved Cormack and Lehane scoring (1,3) and ease of use. Complications associated with the GlideScope[R] have only begun to emerge in the literature.
We report a case of palatopharyngeal wall perforation with the GlideScope[R]. We highlight features pertaining to patient factors, equipment selection and operator technique that may potentially increase the risk of this complication and suggest measures to reduce this complication.
Patient consent for this case report was obtained in accordance with our institutional ethics review board policy and permission to publish this case was obtained from our institutional review board.
The patient was a 45-year-old Chinese woman (57 kg, 156 cm), ASA PS I, scheduled for an elective staging laparotomy and pelvic lymph node dissection for uterine cancer. Airway assessment prior to induction showed a small mouth with limited mouth-opening (4 cm), Mallampati grade 2, normal thyromental distance and full dentition.
Our patient had been recruited for a trial involving the GlideScope[R] for management of a normal airway in one of its randomisation arms. Informed and written consent was taken from the patient with permission to publish the outcomes.
The patient was induced with propofol 2 mg/kg, fentanyl 2 [micro]g/kg and atracurium 0.5 mg/kg. A second generation GlideScope[R] (large blade) was inserted in the midline. The uvula was identified and the epiglottis and vocal cords were clearly seen on the monitor, with a Cormack and Lehane scoring of 1. A styletted endotracheal tube (ETT) was inserted into the oral cavity in the lateral position and then rotated anteriorly to be brought into view on the GlideScope[R] monitor. Slight resistance to insertion was felt during insertion of the ETT and a small pool of blood was immediately noticed collecting in the pharynx.
Direct laryngoscopy with a conventional Macintosh laryngoscope was immediately performed and the ETT was seen penetrating through the right palatopharyngeal wall. A suction catheter was applied gently to remove secretions and blood. The existing ETT was replaced with a new ETT under direct vision. Intravenous dexamethasone 4 mg was given prophylactically to prevent airway oedema. As active bleeding from the wound was not observed, surgery was allowed to proceed. An otolaryngologist was consulted to evaluate the extent of the laceration at the end of surgery prior to awakening the patient. There was a through-and-through 2 cm laceration in the right palatopharyngeal wall, which had stopped bleeding. However, it was deemed that no further treatment was required.
The patient was prescribed a one week course of antibiotics and was counselled postoperatively on the complication that had occurred. She had a mild sore throat for one week and had slight pain while swallowing food. This complication did not result in a delayed discharge from hospital. The patient had no further complications during a follow-up telephone call two weeks later.
A literature search through MEDLINE[R] and the internet revealed 10 other case reports describing such an injury (Table 1). All these reports of airway injury involving the GlideScope[R] have been published within the last two years even though the GlideScope[R] has been available since 2002. Furthermore, there could potentially be other similar complications that go unreported.
We considered the factors we encountered that may have culminated in the injury to our patient, as well as those in the previous case reports, with the aim of identifying measures that may prevent or reduce the incidence of this complication. In reviewing the cases listed in the table, it is emphasised that all 11 patients sustained trauma during insertion of the ETT rather than during GlideScope[R] laryngoscopy itself.
We inserted the ETT tip laterally into the mouth and rotated the tube anteriorly to bring the tip within view. This technique was also used in another case (4) as a technique described to ease insertion of the GlideScope[R] (5-7), especially in tight oral spaces. However, advancing the ETT laterally in a direction perpendicular from the midline may potentially cause impingement of the ETT onto the airway mucosa and increase the risk of tissue perforation (8), especially if pressure is exerted. To achieve visualisation of the larynx, the GlideScope[R] blade causes an upward lifting force on the mandible and anterior pharyngeal tissue, which stretches the tonsillar pillars, making them taut and more susceptible to perforation by an advancing ETT (7). We suggest that introducing the ETT tip medially into the mouth and avoiding rotation may thus decrease the incidence of trauma.
Another possible contributory factor in our case was the tendency for the operator to watch the GlideScope[R] monitor intently after insertion of the GlideScope[R] blade. Focus is often trained on the GlideScope[R] monitor, while the ETT is manoeuvred blindly past the pharynx before coming into view of the GlideScope[R] monitor. This 'blindspot' during insertion where the ETT tip is not observed potentially may result in incorrect ETT advancement and pharyngeal trauma. This practice seems to be frequently described in the previous case reports (4,6,8-12) Instead, direct visualisation of the ETT should be maintained as it is inserted into the mouth and only after the tip of the tube has passed out of direct vision should the GlideScope[R] monitor be viewed. Alternatively, another technique that has been described involves inserting the ETT into the oral cavity first before introducing the GlideScope[R] blade. This is potentially advantageous as appropriate attention is paid during the insertion of the ETT (6,7,11), although the dangers of blind insertion of an ETT should also be considered.
Slight resistance during ETT insertion was noted in our case and several other case reports (6,8,11). There should not be undue force exerted on the ETT during insertion to prevent pharyngeal and palatal laceration (7).
Several authors (2,13) state that there is either a very short or no learning curve associated with tracheal intubation using the GlideScope[R]. However, from our review of the literature of reports that describe the experience level of the operators, only one involved an experienced GlideScope[R] user. The remainder, including our case, have involved novice operators with little experience of the GlideScope[R] (6,7,14). As emphasised by Pacey (15) in a response to a similar case report (9), proper instruction and training is required to develop the skills needed for the proper use of the GlideScope[R]. More formal hands-on practice and close supervision of novice users should be encouraged.
The first generation GlideScope[R] blades were of a single adult size of 18 mm maximum blade thickness (1). The second generation scopes consists of three blade sizes: small (maximum width of 16 mm), midsize (19 mm) and large (26 mm) GlideScope[R] blades (Verathon Medical) (16). The manufacturer provides a rough guide of the appropriate size to use based solely on the patient's body weight. Other factors such as inter-incisor distance, range of neck movement or facial bone features are not taken into consideration. Most of the case reports do not mention which generation GlideScope[R] blades were used. However, it is suggested that using a smaller second generation blade may lead to an increase in safety (6). We used a large blade, which is basically an adult size blade in accordance to the manufacturer's recommendations. Nevertheless, the use of a smaller blade may have been more suitable.
The distal portion of the ETT needs to be in extreme flexion -60[degrees], making it more difficult to pass the ETT through the oropharynx (12) and thus necessitating the use of a rigid stylet. We used a standard ETT with the GlideScope[R] rigid stylet for our case. The standard ETT has a relatively sharp bevelled tip. This, together with a stylet may cause trauma to palatal or pharyngeal structures especially if unnecessary force is used (9). The rigid stylet provided together with the GlideScope[R] is much more rigid than the typical disposable stylets that are widely available (12). Furthermore, we ensured that the stylet did not protrude beyond the ETT. If it did, the hard tip of the stylet may also inflict trauma on the pharynx during insertion (14).
Some authors (9,15) suggest using a soft-edged ETT such as the G1ideRite[TM] system (Verathon Medical). These flexible-tip tubes, modelled after the Parker Flex-Tip[TM] ETT (Parker Medical) (17) have a hemispherical bevel which allows the tip to glide along the airway surfaces without scraping the tissue (18,19). We feel that design modification to the rigid stylet as well as ETT tube for use with GlideScope[R] assisted intubation may decrease the incidence of traumatic intubation.
There are cephalometric differences between Caucasians and Asians and it is suggested that Asians have a smaller hypopharyngeal space compared to that of Caucasians (20). For this reason, perhaps a smaller blade should be used in the Asian population. In our case, perhaps we used an oversized blade which decreased space in the airway in which to manipulate the ETT This may give rise to more complications and trauma to the airway tissue. Further studies need to be done to evaluate the size of the GlideScope[R] blade appropriate for an Asian population.
A possible explanation of the sudden spate in GlideScope[R] complication reporting over a short duration of 15 months could be due to the increasingly widespread use of the GlideScope[R] by anaesthetists of all experience levels for management of the airway. Fortunately, the majority of the cases had minimal sequelae with 36% of the patients requiring some otolaryngology intervention in terms of electrocautery (7,8), surgical sutures (7) or formal wound repair (6). The others did not require any surgical intervention and sustained only a mild sore throat over several days.
While experience is still being obtained, proper training and supervision as well as careful patient selection while using a new airway device is imperative. Intubation using the GlideScope[R] has several advantages over conventional direct laryngoscopy and its use should not be discouraged by the adverse events reported. Instead, through an increased awareness for potential complications, better training and supervision, appropriate equipment and patient selection, the incidence of this complication can be reduced.
(1.) Sun DA, Warriner CB, Parsons DG, Klein R, Umedaly HS, Moult M. The GlideScope Video Laryngoscope: randomized clinical trial in 200 patients. Br J Anaesth 2005; 94:381-384.
(2.) Cooper RM, Pacey JA, Bishop MJ, McCloskey SA. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anesth 2005; 52:191-198.
(3.) Rai MR, Dering A, Verghese C. The Glidescope system: a clinical assessment of performance. Anaesthesia 2005; 60:6064.
(4.) Cross P, Cytryn J, Cheng KK Perforation of the soft palate using the GlideScope videolaryngoscope. Can J Anesth 2007; 54:588-589.
(5.) Kramer DC, Osborn IP More maneuvers to facilitate tracheal intubation with the GlideScope. Can J Anesth 2006; 53:737.
(6.) Chin KJ, Arango ME, Paez AF, Turkstra TP Palatal injury associated with the GlideScope. Anaesth Intensive Care 2007; 35:449-450.
(7.) Cooper RM. Complications associated with the use of the GlideScope videolaryngoscope. Can J Anesth 2007; 54:54-57.
(8.) Chou MKF, Yeo VST, See JJ. Another complication associated with videolaryngoscopy. Can J Anesth 2007; 54:322-324.
(9.) Malik AM, Frogel JK. Anterior tonsillar pillar perforation during Glidescope video laryngoscopy. Anesth Analg 2007; 104:1610-1611.
(10.) Hsu W-T, Hsu S-C, Lee Y-L, Huang J-S, Chen C-L. Penetrating injury of the soft palate during GlideScope intubation. Anesth Analg 2007; 104:1609-1610.
(11.) Hirabayashi Y. Pharyngeal injury related to GlideScope videolaryngoscope. Otolaryngol Head Neck Surg 2007; 137:175-176.
(12.) Vincent RW, MP, Brockwell R, Magnuson J. Soft palate perforation during orotracheal intubation facilitated by the GlideScope videolaryngoscope. J Clin Anesth 2007; 19:619-621.
(13.) Huang W-T, Huang C-Y, Chung Y -T. Clinical comparisons between GlideScope video laryngoscope and Trachlight in simulated cervical spine instability. J Clin Anesth 2007; 19:110-114.
(14.) Krasser K. Injuries Associated with GlideScope video laryngoscopy-assisted tracheal intubation. Internet Journal of Airway Management 4:2006-2007. From http://www.adair.at/ijam/volume04/correspondence04/default.htm Accessed May 2008.
(15.) Pacey JA. In response to anterior tonsillar pillar perforation during Glidescope video laryngoscopy. Anesth Analg 2007; 104:1611.
(16.) Verathon Medical. GlideScope Videolaryngoscopes. From http://www.Vrathon.com/PDFs/0900-1223-03-86.pdf Accessed May 2008.
(17.) Parker Medical. Parker Flex-Tip[TM] Tracheal Tube, Tube. From http://www.parkermedical.com/PDF/Parker_Tube.pdfAccessed May 2008.
(18.) Makino H, Katoh T, Kobayashi S, Bito H, Sato S. The effects of tracheal tube tip design and tube thickness on laryngeal pass ability during oral tube exchange with an introducer. Anesth Analg 2003; 97:285-288.
(19.) Kristensen MS. The Parker Flex-Tip tube versus a standard tube for fiberoptic orotracheal intubation: a randomized double-blind study. Anesthesiology 2003; 98:354-358.
(20.) Tan SM, Sim YY, Koay CK The ProSeal laryngeal mask airway size selection in male and female patients in an Asian population. Anaesth Intensive Care 2005; 33:239-242.
W. L. LEONG *, Y. LIM [[dagger]], A. T. H. SIA [[double dagger]]
Department of Women's Anaesthesia, KK Women's and Children's Hospital, Singapore
* M.B., B.S., Medical Officer.
[[dagger]] M.Med.(Anaesthesia), Consultant.
[[double dagger]] M.Med.(Anaesthesia), Head of Department, Senior Consultant.
Address for reprints: Dr W L. Leong, Department of Women's Anaesthesia, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899.
Accepted for publication on June 24, 2008.
TABLE 1 Summary of case reports Author Current case Vincent (12) Patient 45-year-old female 55-year-old male Co-morbidities 156 cm Large exophytic right 57 kg supraglottic mass Operation/ Staging laparotomy for Direct laryngoscopy and procedure uterine carcinoma biopsy of supraglottic mass Relevant Mallampati 2. Known supraglottic mass airway Interincisor distance established on assessment 4 cm. Normal thyromental videoscopic stroboscopic distance. Full dentition. examination Equipment Styletted #7.0 ETT Styletted #6.5 ETT (60[degrees] angle) (60[degrees] angle) Operator Novice Not stated experience Method of ETT tip introduced into Firm pressure and gentle insertion. mouth in a lateral manipulation Difficulty position then rotated encountered anteriorly. Slight resistance on passing the laryngeal inlet. Perforation Right palatopharyngeal Right lateral soft palate fold Otolaryngology Not required Not required intervention Sequelae Sore throat for 7 days. Nil. Pain on swallowing. Palatal defect had closed 9 days after. Author Hirabayashi (11) Cross (4) Patient 57-year-old female 31-year-old male Co-morbidities 148 cm Gunshot wound to 46 kg anterior mandible Operation/ Not stated Repair of mandible procedure and oesophagus Relevant Narrow mouth Mallampati 1. airway Adequate thyromental assessment distance, mouth-opening and dentition. Equipment Hockey stick shaped Styletted ETT stylet (90[degrees] angle) Operator Not stated Experienced experience Method of Moderate difficulty ETT tip introduced insertion. encountered in directing into the mouth in Difficulty the ETT into the glottis. a lateral position encountered Manipulation of the ETT 3 and then rotated times. anteriorly Perforation Palatoglossal arch Soft palate Otolaryngology Not required Not required intervention Sequelae Not stated Swallowing difficulties Author Hsu (10) Malik (9) Patient 29-year-old male 72-year-old male Co-morbidities Previous Myotonia congenita. polypectomy Hiatus hernia with reflux. Operation/ Rhinoplasty Resection of thoracic procedure spinal cord arterio-venous malformation Relevant Not stated Mallampati 2. airway Limited mouth opening. assessment Cervical spine--normal range of movement. Previous C&L grade 3 with direct laryngoscopy. C&L grade 1 with GlideScope[R]. Equipment Styletted ETT Rigid stylet #8.0 ETT (60[degrees] angle) Operator Not stated Not stated experience Method of Not stated Not stated insertion. Difficulty encountered Perforation Right soft palate Right anterior tonsillar pillar Otolaryngology Not required Not required intervention Sequelae Nil Sore throat for 1 day Author Chin (6) Krasser (14) Patient 46-year-old female Not stated Co-morbidities BMI 40 Not stated Operation/ Elective craniotomy and Elective thyroid procedure tumour resection surgery Relevant Mallampati 3. Not stated airway Narrow mouth. assessment Large tongue. Complete dentition. Inter-incisor distance 4 cm. Prominent faucial pillars and soft palate. C&L grade 2 on direct laryngoscopy. Equipment Styletted #7.5 ETT Not stated (90[degrees] angle) Operator Novice Novice experience Method of Resistance on inserting Multiple attempts insertion. ETT (2 attempts). to insert the ETT Difficulty Subsequently intubated by Stylet protruded encountered direct laryngoscopy. beyond distal end of the ETT Perforation Right soft palate Soft palate Otolaryngology Surgically repaired Not stated intervention Sequelae Well healed at post Postpone surgery operative day 5 due to bleeding Author Choo (8) Cooper (7) Patient 62-year-old female 57-year-old female Co-morbidities Not stated Not stated Operation/ Ureteroscopy Facial scar revision procedure Relevant Not stated Hemifacial airway microsomia. assessment Small mouth. Limited cervical extension. C&L grade 4 on direct laryngoscopy. Equipment Styletted #7.5 ETT Styletted ETT Operator Not stated Not stated experience Method of Slight resistance on Difficulty directing insertion. passing the ETT into larynx. Difficulty laryngeal inlet 2 unsuccessful encountered attempts by anaesthetists. Otolaryngologist intubated using GlideScope[R]. Perforation Right Right palatopharyngeal palatopharyngeal fold arch Otolaryngology Electrocautery Sutures intervention Sequelae Sore throat. Discharged home Overnight the following day observation. Author Cooper (7) Patient 72-year-old female Co-morbidities Severe aortic stenosis, triple vessel disease, acute myocardial infarction, diabetes mellitus, hypertension, mild renal insufficiency Operation/ Aortic valve replacement procedure and coronary artery bypass surgery Relevant Edentulous. airway Mallampati 3. assessment C&L grade 1 on GlideScope[R]. Equipment Styletted ETT Operator Novice experience Method of 2 attempts required to insertion. bring ETT into view on Difficulty the monitor encountered Perforation Right pal atopharyngeal arch Otolaryngology Electrocautery intervention Sequelae Died from unrelated causes ETT = endotracheal tube, C&L = Cormack and Lehane, BMI = Body Mass Index.
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