Direct laryngoscopy was introduced in 1895 by Afred Kirstein. Since that time, physicians have developed instruments to improve visualization of the larynx while limiting tissue trauma. The Macintosh and Miller laryngoscope blades were developed in the 1940s and have been the primary tool for endotracheal (ET) intubation.1 Although they have been effectively used for most ET intubations, there are limitations to their ability to allow direct visualization of the glottis and surrounding structures. Numerous adjuncts have since been developed to assist in ET intubation.1
The recent development of video laryngoscopy marks a new era in airway management. Traditional direct laryngoscopy requires alignment of the oral, pharyngeal, and laryngeal axes to visualize the glottis (Figure 6-5). Despite mechanical manipulation, it is not always possible to align these three axes. The major advantage of video laryngoscopy is that it does not require the Emergency Physician to align the three airway axes, reducing the need for manipulation and potential traumatic forces on the airway.2 Through the use of a video camera, video laryngoscopes provide a superior view of the glottis when compared to traditional direct laryngoscopy. The eye of the video laryngoscope camera is within centimeters of the glottis and provides a wider angle of vision than the 15° of traditional direct laryngoscopy. The video monitor magnifies the view of the airway making structures easier to visualize. This chapter reviews a representative number and types of devices currently available and used in Emergency Departments.
The Pentax Airway Scope (Pentax Medical CO., Montvale, NJ), also known as the Pentax AWS or the AWS, is a rigid video laryngoscope (Figure 13-1). It incorporates the blade, camera, and an ET tube targeting mechanism into one device. It is designed for use in the prehospital setting, Emergency Department, and operating room.3,4
The Pentax AWS (Photo courtesy of Pentax Medical Co., Montvale, NJ).
Indications and Contraindications
The AWS can be used for elective and emergent intubations. Patients with their head and neck immobilized can benefit from intubation with this device. It provides better visualization of the glottis, decreased cervical movement, and a higher success rate in comparison to traditional direct laryngoscopy.5,6 Intubation with the AWS produces less airway stimulation than either the Glidescope or traditional laryngoscopes, thus minimizing the hemodynamic changes associated with intubation.6,7 There are no contraindications to the use of the AWS.
The AWS incorporates an imaging system and a targeting system into one portable tool. It is ergonomically designed to minimize tissue trauma. Its use does not require the alignment of the three airway axes. The imaging system provides an illuminated 90° field of view.3 The AWS produces better glottic visualization than traditional direct laryngoscopy.32 The ...