THE WuScope system (Achi Corp., Fremont, CA, and Asahi Optical Co., Pentax, Tokyo, Japan) is a fiberoptic laryngoscopy system composed of a curved, tubular, bivalved, rigid blade and a flexible fiberscope. 1The WuScope system integrates the features of both rigid and flexible laryngoscopy and eliminates the shortcomings of each. We describe two complex clinical situations in which the use of a WuScope laryngoscope resulted in successful endotracheal intubations.
A 67-yr-old, morbidly obese woman (160 cm, 125 kg) was brought to the emergency room by a paramedic unit after developing acute neck expansion at home. She had undergone left carotid endarterectomy 6 days previously. While in the ambulance, her neck swelling continued to expand despite the external compression applied by paramedic personnel. Her breathing became stridulous, resulting in severe respiratory distress, and she became unconscious. The paramedic team attempted tracheal intubation without success, and they performed mask ventilation until arrival at the emergency room. An emergency room physician attempted tracheal intubation without success; therefore, an emergency cricothyrotomy was performed, and a 6-mm endotracheal tube (ETT) was inserted into the trachea. After tube insertion, an electrocardiogram revealed asystole, and cardiopulmonary resuscitation was initiated. Two minutes later, sinus tachycardia was established, and the patient was transferred to the operating room for carotid artery repair. Throughout the entire emergency room course and transfer to the operating room, a surgical resident maintained pressure over the expanding neck and cricothyrotomy site, which also was bleeding. The patient was anesthetized with isoflurane and fentanyl, and muscle relaxation was achieved with cisatracurium. Lung ventilation through the small ETT became extremely difficult, requiring ventilation with peak inspiratory pressures of 65 cm H2O. The oxyhemoglobin saturation, assessed by pulse oximetry, ranged between 85 and 89% on fraction of inspired oxygen (Fio2) 1.0. As soon as the surgeon controlled the carotid artery bleeding, we decided to exchange the ETT. The large adult WuScope was preloaded with an 8.0-mm ETT. With uninterrupted lung ventilation, the WuScope blade was inserted through the middle of the mouth, and the vocal cords were visualized despite the fact that the posterior left pharyngeal wall was bulging toward the glottis. Under direct vision, the new ETT was placed through the glottic opening without difficulty. After confirming adequate lung ventilation, the original ETT was withdrawn. The new ETT was then advanced beyond the cricothyrotomy incision (fig. 1). Lung ventilation immediately improved, with peak pressures below 30 cm H2O, while oxyhemoglobin saturation increased to 99%. Examination of the removed ETT revealed blood clots that narrowed its internal diameter, explaining the difficulty in ventilating.
A 58-yr-old woman (162 cm, 60 kg) with a history of laryngeal papillomatosis was admitted for her third laryngeal surgery—laser tumor debulking. While sitting in the bed, her voice was hoarse, and her breathing was stridulous. After anesthesia was induced for the first surgery, the vocal cords could not be visualized with direct laryngoscopy. At that time, the ETT was placed blindly, aided by an intubating stylet, which resulted in bleeding from the traumatized tissues. For her second surgery, fiberoptic intubation was attempted, and although the fiberoptic bronchoscope was successfully placed into trachea without bleeding, the ETT could not be passed through the glottis. Attempts to forcefully insert the ETT over the fiberoptic bronchoscope resulted in massive oral bleeding, necessitating the establishment of an emergency surgical airway. For the present surgery, the plan for tracheal intubation included WuScope-assisted, awake intubation, with an otolaryngologist standing by to perform an emergency tracheostomy if needed. After sedation with 1 mg midazolam and 50 μg fentanyl, we anesthetized the oropharynx with the patient in the sitting position. Once we had achieved adequate oropharyngeal anesthesia, we lowered the bed to a semisitting position and inserted the adult WuScope blade through the middle of the mouth. The patient's glottic opening was narrow due to extensive tumor growth. We introduced an airway exchange catheter (AEC; Cook Critical Care, Bloomington, IN), first through the WuScope preloaded ETT and then through the narrow glottic opening. The placement of the AEC through the glottis was achieved without bleeding, and the patient tolerated it well. Then we used a well-lubricated, 5.5-mm laser ETT and passed it with some difficulty through the narrow vocal cords (fig. 2). This was followed by administration of propofol. The glottic bleeding, present after the placement of the ETT, was controlled with laser coagulation. During a 60-min laser surgery, total intravenous anesthesia was maintained with propofol–alfentanil infusion and an air–oxygen mixture (Fio2= 0.25). At the completion of the surgery and prior to tracheal extubation, we instilled 2% lidocaine through the ETT and allowed the patient to awaken. With the patient fully awake, we deflated the tracheal cuff and tested her ability to breathe around the occluded ETT. Then we reintroduced the AEC through the ETT into the trachea. The ETT was taken out, with the AEC left in the trachea and taped to the face with a depth marker showing 23 cm at the lip, and the patient was sent to the recovery room. The AEC was removed 1 h later, when there were no signs of breathing difficulty. The patient was discharged to home the next day.
The WuScope system is a fiberoptic intubating device that combines a fiberoptic scope with a rigid laryngoscope. 1It allows tracheal intubation without the need for head extension, tongue lifting, or forceful jaw opening, because a 110° handle-to-blade angle allows easy visualization of the glottis in many difficult clinical situations. 2–5The WuScope is typically inserted in the midline of the mouth. The handle is then rotated toward the laryngoscopist, with the blade gently advanced across the convexity of the tongue. Once the larynx is visualized, the ETT may be advanced between the cords under direct vision, as we did in our first patient. Manipulating the scope side to side or back and forth may be needed to optimize the laryngeal view and to facilitate direction of the ETT toward the glottis. Alternatively, a suction catheter or AEC may be advanced through the ETT into the trachea. This catheter serves as a stylet, which directs the ETT through the glottis.
Expanding neck hematoma after carotid endarterectomy represents one of the most emergent and difficult situations for tracheal intubation. Attempts to intubate the trachea by direct laryngoscopy may be impossible when the airway anatomy is distorted. ETT exchange in these cases may pose substantial risk for the patient. We were unable to perform adequate ventilation through the small and obstructed (because of blood clots) ETT inserted through the cricothyroidotomy; therefore, we needed to replace the ETT. Bleeding around the cricothyroidotomy incision and low oxyhemoglobin saturations were viewed as risks for the ETT exchange through the same incision, as even a short period of interrupted ventilation could have had catastrophic consequences for this patient. We decided to exchange the ETT by using WuScope rigid laryngoscopy. In this case, tracheal intubation was performed without the use of stylet guidance. The design of the WuScope overcomes some complex anatomic obstacles, and the blade design offers both easy entrance into the oropharynx and visualization of the anteriorly positioned glottic opening. At the same time, the tubular blade protects the fiberscope lens from secretions, blood, or redundant tissues better than during flexible fiberoptic intubation.
In our second patient, conventional fiberoptic intubation and attempts to place the ETT resulted in massive glottic hemorrhage during her previous surgery. We opted to use the WuScope system for intubation. The WuScope allowed direct visualization of the tumorous glottis and atraumatic insertion of the jet–endotracheal tube exchanger. Once passed beyond the glottis, this exchanger would have allowed the use of jet ventilation if difficulties had occurred. We consequently successfully intubated the trachea with minimal trauma. Because laser surgery can result in delayed swelling with consequent airway compromise, 6,7we monitored the patient for 24 h before her uneventful discharge.
In conclusion, WuScope rigid laryngoscopy may be used in some very complex clinical situations. However, as with any other technique, failure to intubate may occur even with this technique. Experience with the WuScope system should be acquired first on uncomplicated airways before attempting its use on difficult airways.