Advanced airway management is the subset of airway management that involves advanced training, skill, and invasiveness. It encompasses various techniques performed to create an open or patent airway – a clear path between a patient's lungs and the outside world. These techniques are used when a patient is unable to maintain airway patency, protect the airway from aspiration, or achieve adequate oxygenation and ventilation on their own.
This is accomplished by clearing or preventing obstructions of airways. There are multiple causes of potential airway obstructions, including the patient's own tongue or other anatomical components of the airway, foreign bodies, excessive amounts of blood and body fluids, or aspiration of food particles.
Unlike basic airway management, such as the head tilt/chin lift or jaw-thrust maneuver, advanced airway management relies on the use of medical equipment and advanced training in anesthesiology, emergency medicine, or critical care medicine. Certain invasive airway management techniques can be performed with visualization of the glottis or "blind" – without direct visualization of the glottis. Visualization of the glottis can be accomplished either directly by using a laryngoscope blade or by utilizing newer video technology options.
Supraglottic airways in increasing order of invasiveness are nasopharyngeal (NPA), oropharyngeal (OPA), and laryngeal mask airways (LMA). Laryngeal mask airways can even be used to deliver general anesthesia or intubate a patient through the device. These are followed by infraglottic techniques, such as tracheal intubation and finally surgical techniques.
Advanced airway management is a key component in cardiopulmonary resuscitation, anesthesia, emergency medicine, and intensive care medicine. Within Advanced Cardiac Life Support (ACLS) algorithms, advanced airway placement may be considered to optimize oxygenation and ventilation while minimizing interruptions in chest compressions. The "A" in the ABC mnemonic for dealing with critically ill patients stands for airway management. Many airways are straightforward to manage. However, some can be challenging. Such difficulties can be predicted to some extent by a physical exam. Common methods of assessing difficult airways include a Mallampati score, Cormack-Lehane classification, thyromental distance, degree of mouth opening, neck range of motion, body habitus, and malocclusion (underbite or overbite). A recent Cochrane systematic review examines the sensitivity and specificity of the various bedside tests commonly used to predict difficulty in airway management.
Pharyngeal airways Pharyngeal airway devices are used in spontaneously breathing patients to move the tongue away from the back of the throat to restore airway patency. Obstruction of the upper airway caused by the tongue most commonly occurs during decreased levels of consciousness. Pharyngeal airway devices include oropharyngeal airways (OPAs) and nasopharyngeal airways (NPAs). These devices are the simplest artificial airways.
Oropharyngeal airways
An oropharyngeal airway (OPA) is a rigid tube that is inserted into the mouth through the oropharynx and placed above the tongue to move it away from the back of the throat. They are more commonly used than nasopharyngeal airways (NPAs). OPAs should only be used in profoundly unresponsive or unconscious patients without a gag reflex. Placement of the device may stimulate the gag reflex and cause vomiting, aspiration, and laryngospasm. Complications from OPA placement include damage to the teeth and the lingual nerve, which may cause changes in taste and sensation of the tongue.
Nasopharyngeal airways
A nasopharyngeal airway (NPA) is a flexible tube that is passed through the nose into the back of the throat. They are the artificial airways of choice in patients who are conscious and have intact gag reflexes because they are less likely to stimulate the gag reflex than oropharyngeal airways (OPAs). NPAs can also be used in other situations where OPAs cannot, such as in patients with restricted mouth opening or oral trauma. NPAs are generally not recommended if there is suspicion of a fracture to the base of the skull due to the risk of the tube entering the skull. They are also contraindicated in the presence of significant facial trauma. Nosebleeds are a complication of NPAs that may result from the use of excessive force or a lack of lubrication during placement.
Extraglottic airways Extraglottic airway devices (EGDs) create a patent airway without entering the trachea. These devices are highly effective for providing oxygenation and ventilation. They can be used as primary airway devices, such as during CPR, or as rescue devices in situations where securing an airway using other devices has failed. EGDs are especially effective rescue devices for obese patients and patients with significant facial trauma. EGDs do not protect the trachea from obstruction or aspiration. They may be used for several hours until a definitive airway can be secured.
Each type of EGD has different features, including the ability to remove air from the stomach (gastric decompression) and perform tracheal intubation. All EGDs can be placed without directly seeing the glottis (also called "blind" placement). EGDs can be classified into supraglottic airways and retroglottic airways.
Supraglottic airways Supraglottic airway devices (SGAs) create a seal over the glottic opening to route oxygen directly into the trachea. The SGAs consist entirely of laryngeal masks. Several manufacturers produce these devices, the most well known being the laryngeal mask airway (LMA). Success rates of SGAs in securing airways are similar between the different models, and these devices provide effective ventilation in more than 98% of patients. SGAs can be placed in under 30 seconds, making them advantageous for emergency use. Serious complications are rare and usually result from nerve and soft tissue trauma in the pharynx during placement.
Retroglottic airways Retroglottic airway devices (RGAs) pass behind the glottis and into the esophagus to create a seal allowing oxygen to be delivered directly to the trachea. The RGAs are designed as laryngeal tubes. Examples of RGAs include the Combitube and the King LT. Studies comparing the effectiveness between the RGAs are lacking. Like SGAs, most complications from RGAs result from trauma to the pharynx during placement.
Tracheal intubation
Tracheal intubation, often simply referred to as intubation, is the placement of a flexible plastic or rubber endotracheal tube (ETT) into the trachea to maintain an open airway, allow for effective ventilation, protect the airway from aspiration (when a cuffed ETT is used), and to serve as a conduit through which to administer inhaled anesthetics. It is frequently performed in surgery, critically injured, ill or anesthetized patients to facilitate ventilation of the lungs, including mechanical ventilation, and to prevent the possibility of asphyxiation or airway obstruction. The most widely used route is orotracheal intubation, in which an endotracheal tube is passed through the mouth, through the vocal cords, and into the trachea. In a nasotracheal intubation, a nasotracheal tube (NTT) is passed through the nose, through the vocal cords, and into the trachea.
Indications There are specific indications or guidelines for deciding a more invasive and more secure airway is worth the associated risk: respiratory failure apnea or the suspension of breathing decreased or altered level of consciousness, rapid mental status change, Glasgow Coma Scale score less than 8 (GCS<8). major trauma, such as penetrating injury to the abdomen or chest direct airway injury or facial burns high risk of aspiration
Methods Direct Laryngoscopy Classically, tracheal intubation has been performed utilizing direct laryngoscopy to obtain direct visualization of the vocal cords. There are multiple different laryngoscope blade styles, shapes, and lengths from which to choose based on patient anatomy and clinician preference. In North America, the Macintosh blade is the most commonly used curved blade while the Miller blade is the most common straight blade. Many modern laryngoscopes are equipped with a fiberoptic light source to aid in visualization. Regardless of blade shape, direct laryngoscopy technique involves passage of the laryngoscope through the mouth and into the back of the throat. Manipulation of the neck and lifting of the tongue allows for direct visualization of the larynx and vocal cords by the operator. Following visualization, the endotracheal tube can be passed along the blade, through the vocal cords, and into the trachea. Adjuncts such as a bougie (tracheal introducer) or stylet may be used to assist with endotracheal tube placement, particularly in cases where visualization of the vocal cords is limited. A bougie can be advanced into the trachea first, with the endotracheal tube subsequently railroaded over it.
Rapid Sequence Induction (RSI)
Rapid sequence induction (RSI) is a technique used to facilitate tracheal intubation in patients at high risk of aspiration or with respiratory failure. RSI involves the administration of a rapid-acting sedative (induction agent) followed immediately by a neuromuscular blocking agent to induce unconsciousness and paralysis, allowing prompt placement of an endotracheal tube while minimizing the risk of gastric aspiration. Bag-mask ventilation is often limited prior to intubation to reduce gastric insufflation. RSI is commonly performed in emergency medicine, critical care, and trauma settings.
Video Laryngoscopy Multiple intubation tools are now available with built-in video technology, also known as video laryngoscopy. The GlideScope model utilizes a curved laryngoscopic blade with an integrated camera connected to a large external monitor. The McGrath model has a compact design with a small display directly attached to the laryngoscopic blade. The operator introduces the video laryngoscope through the mouth with a technique similar to direct laryngoscopy. The larynx and vocal cords are visualized via the camera and the operator is able to pass the endotracheal tube through the vocal cords and into the trachea under direct visualization on the video monitor. Studies have shown that when compared to direct laryngoscopy, video laryngoscopy resulted in fewer failed intubation attempts, especially in patients with known difficult airways.Lewis SR, Butler AR, Parker J, Cook TM, Smith AF. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database of Systematic Reviews 2016, Issue 11. Art. No: CD011136 DOI: 10.1002/14651858.CD011136.pub2. Limitations of video laryngoscopy exist and prevent the exclusive use of this method over direct laryngoscopy. Excessive blood and saliva in the airway can cover the camera lens on the video laryngoscope and obscure effective visualization of the anatomy, preventing effective intubation attempts. This is of importance in patients with trauma to their airway, increasing the amount of blood present, and patients taking sialogogues, or drugs that increase the flow of saliva.
Fiberoptic Intubation