Editing Tracheal intubation (section)

===Emergencies===
Tracheal intubation in the emergency setting can be difficult with the fiberoptic bronchoscope due to blood, vomit, or [[secretion]]s in the airway and poor patient cooperation. Because of this, patients with massive facial injury, complete upper airway obstruction, severely diminished ventilation, or profuse upper airway bleeding are poor candidates for fiberoptic intubation.<ref name=Morris1994/> Fiberoptic intubation under general anesthesia typically requires two skilled individuals.<ref name=Ovassapian1991/> Success rates of only 83–87% have been reported using fiberoptic techniques in the emergency department, with significant [[epistaxis|nasal bleeding]] occurring in up to 22% of patients.<ref name=Delaney1988/><ref name=Mlinek1990/> These drawbacks limit the use of fiberoptic bronchoscopy somewhat in urgent and emergency situations.<ref name=Caplan2003/><ref name=Hagberg2007/>

Personnel experienced in direct laryngoscopy are not always immediately available in certain settings that require emergency tracheal intubation. For this reason, specialized devices have been designed to act as bridges to a definitive airway. Such devices include the laryngeal mask airway, cuffed [[Human pharynx|oropharyngeal]] airway and the esophageal-tracheal combitube ([[Combitube]]).<ref name=Foley2000/><ref name=Frass2007/> Other devices such as rigid stylets, the lightwand (a blind technique) and indirect fiberoptic rigid stylets, such as the Bullard scope, Upsher scope and the WuScope can also be used as alternatives to direct laryngoscopy. Each of these devices have its own unique set of benefits and drawbacks, and none of them is effective under all circumstances.<ref name=Hung2007/>

====Rapid-sequence induction and intubation====
[[Image:McCoy Mac Blades.jpg|thumb|400px|alt=Laryngoscopes prepared in an emergency theatre|Laryngoscopes prepared for emergency anaesthesia]]
{{main|Rapid sequence induction}}
Rapid sequence induction and intubation (RSI) is a particular method of induction of general anesthesia, commonly employed in emergency operations and other situations where patients are assumed to have a full stomach. The objective of RSI is to minimize the possibility of [[Regurgitation (digestion)|regurgitation]] and pulmonary aspiration of gastric contents during the induction of general anesthesia and subsequent tracheal intubation.<ref name=Stone2000/> RSI traditionally involves preoxygenating the lungs with a tightly fitting oxygen mask, followed by the sequential administration of an intravenous [[hypnotic|sleep-inducing]] agent and a rapidly acting neuromuscular-blocking drug, such as [[rocuronium]], [[succinylcholine]], or [[cisatracurium|cisatracurium besilate]], before intubation of the trachea.<ref name=Suresh2007/>

One important difference between RSI and routine tracheal intubation is that the practitioner does not manually assist the ventilation of the lungs after the onset of general anesthesia and [[apnea|cessation of breathing]], until the trachea has been intubated and the cuff has been inflated. Another key feature of RSI is the application of manual '[[cricoid pressure]]' to the cricoid cartilage, often referred to as the "Sellick maneuver", prior to instrumentation of the airway and intubation of the trachea.<ref name=Stone2000/>

Named for British anesthetist Brian Arthur Sellick (1918–1996) who first described the procedure in 1961,<ref name=Sellick1961/> the goal of cricoid pressure is to minimize the possibility of regurgitation and pulmonary aspiration of gastric contents. Cricoid pressure has been widely used during RSI for nearly fifty years, despite a lack of compelling evidence to support this practice.<ref name=Salem1974/> The initial article by Sellick was based on a small sample size at a time when high [[tidal volume]]s, [[Trendelenburg position|head-down positioning]] and [[barbiturate]] anesthesia were the rule.<ref name=Maltby2002/> Beginning around 2000, a significant body of evidence has accumulated which questions the effectiveness of cricoid pressure. The application of cricoid pressure may in fact displace the esophagus laterally<ref name=Smith2003/> instead of compressing it as described by Sellick. Cricoid pressure may also compress the glottis, which can obstruct the view of the laryngoscopist and actually cause a delay in securing the airway.<ref name=Haslam2005/>

Cricoid pressure is often confused with the "BURP" (Backwards Upwards Rightwards Pressure) maneuver.<ref name=Knill1993/> While both of these involve digital pressure to the anterior aspect (front) of the laryngeal apparatus, the purpose of the latter is to improve the view of the glottis during laryngoscopy and tracheal intubation, rather than to prevent regurgitation.<ref name=Takahata1997/> Both cricoid pressure and the BURP maneuver have the potential to worsen laryngoscopy.<ref name="pmid16713784">{{cite journal | vauthors = Levitan RM, Kinkle WC, Levin WJ, Everett WW | title = Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy | journal = Ann Emerg Med | volume = 47 | issue = 6 | pages = 548–55 | date = June 2006 | pmid = 16713784 | doi = 10.1016/j.annemergmed.2006.01.013 }}</ref>

RSI may also be used in prehospital emergency situations when a patient is conscious but respiratory failure is imminent (such as in extreme trauma). This procedure is commonly performed by flight paramedics. Flight paramedics often use RSI to intubate before transport because intubation in a moving fixed-wing or rotary-wing aircraft is extremely difficult to perform due to environmental factors. The patient will be paralyzed and intubated on the ground before transport by aircraft.

====Cricothyrotomy====
{{Main|Cricothyrotomy}}
[[File:Larynx external en.svg|thumb|375px|alt=In cricothyrotomy, the incision or puncture is made through the cricothyroid membrane in between the thyroid cartilage and the cricoid cartilage|In cricothyrotomy, the incision or puncture is made through the [[Cricothyroid ligament|cricothyroid membrane]] in between the [[thyroid cartilage]] and the [[cricoid cartilage]]]]
[[File:Kit de Cricothyroïdotomie.JPG|thumb|alt=Cricothyrotomy kit|[[Cricothyrotomy]] kit]]

A cricothyrotomy is an incision made through the skin and [[Cricothyroid ligament|cricothyroid membrane]] to establish a patent airway during certain life-threatening situations, such as airway obstruction by a foreign body, angioedema, or massive facial trauma.<ref name=Mohan2009/> A cricothyrotomy is nearly always performed as a last resort in cases where orotracheal and nasotracheal intubation are impossible or contraindicated. Cricothyrotomy is easier and quicker to perform than tracheotomy, does not require manipulation of the cervical spine and is associated with fewer complications.<ref name=Katos2007/>

The easiest method to perform this technique is the needle cricothyrotomy (also referred to as a [[percutaneous]] dilational cricothyrotomy), in which a large-bore (12–14 [[Needle gauge comparison chart|gauge]]) [[Peripheral venous catheter|intravenous catheter]] is used to puncture the cricothyroid membrane.<ref name=Melker2007/> Oxygen can then be administered through this catheter via [[Jet ventilation|jet insufflation]]. However, while needle cricothyrotomy may be life-saving in extreme circumstances, this technique is only intended to be a temporizing measure until a definitive airway can be established.<ref name=ATLS2004CH2/> While needle cricothyrotomy can provide adequate oxygenation, the small diameter of the cricothyrotomy catheter is insufficient for elimination of carbon dioxide (ventilation). After one hour of [[Apnea#Apneic oxygenation|apneic oxygenation]] through a needle cricothyrotomy, one can expect a [[Arterial blood gas|PaCO<sub>2</sub>]] of greater than 250&nbsp;mm Hg and an arterial [[pH]] of less than 6.72, despite an oxygen saturation of 98% or greater.<ref name=Frumin1959/> A more definitive airway can be established by performing a surgical cricothyrotomy, in which a {{convert|5|to|6|mm|in|2|abbr=on}} endotracheal tube or tracheostomy tube can be inserted through a larger incision.<ref name=Gibbs2007/>

Several manufacturers market prepackaged cricothyrotomy kits, which enable one to use either a wire-guided percutaneous dilational (Seldinger) technique, or the classic surgical technique to insert a polyvinylchloride catheter through the cricothyroid membrane. The kits may be stocked in hospital emergency departments and operating suites, as well as ambulances and other selected [[Emergency medical services|pre-hospital]] settings.<ref name=Benkhadra2008/>