tracheal ion - wikip

Intervention:

Tracheal intubation

Tracheal intubation being practiced on a mannequin(orotracheal technique using a laryngoscope.

ICD-10 code:

ICD-9 code: 96.04

(http://icd9cm.chrisendres.com

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srchtext=96.04&

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action=search)

MeSH D007442

(http://www.nlm.nih.gov

/cgi/mesh

/2007/MB_cgi?field=uid&

term=D007442)

Other codes:

Tracheal intubation

From Wikipedia, the free encyclopedia

(Redirected from Endotracheal intubation)

Tracheal intubation (often simply referred

to as intubation) is the placement of a

flexible plastic tube into the trachea to

protect the airway and provide a means of

mechanical ventilation. The most common

route for tracheal intubation is orotracheal

where, with the assistance of a

laryngoscope, an endotracheal tube is

passed through the oropharynx, glottis, and

larynx into the trachea. A high-volume,

low-pressure cuff is then typically inflated

near the distal tip of the tube to help secure

it in place and protect the airway from

blood, gastric contents and other

secretions. Another route for tracheal

intubation is nasotracheal, where an

endotracheal tube is passed through the

nasopharynx, glottis, and larynx into the

trachea. Other routes for intubation of the

trachea include the cricothyrotomy (used

almost exclusively in emergency

circumstances), and the tracheotomy (used

primarily in circumstances where a

prolonged need for airway support is

anticipated).

After the trachea has been intubated and

the tube has been secured to the face or

neck, the proximal end of the tube is

connected to a T-piece, anesthesia

breathing circuit, bag valve mask device, or

a mechanical ventilator. Once there is no

longer a need for ventilatory assistance

and/or protection of the airway, the

tracheal tube may be removed; this is

referred to as extubation of the trachea (or decannulation, in the case of a surgical airway such as a

cricothyrotomy or a tracheotomy).

Contents

1 History

1.1 Pre-19th century

1.2 19th century

1.3 20th century

Tracheal intubation - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Endotracheal_intubation

1 of 21 7/27/2010 1:01 PM

This portrait, though undated,

supports the view that

tracheotomy was practiced in

ancient history.

1.4 21st century

2 Indications

3 Predicting difficulty of tracheal intubation

4 Equipment

4.1 Laryngoscopes

4.2 Stylets

4.3 Tracheal tubes

4.4 Methods to confirm tube placement

5 Tracheal tube maintenance

6 Special situations

6.1 Emergency intubation

6.2 Rapid-sequence intubation

6.3 Nasotracheal intubation

6.4 Difficult intubation

6.5 Cricothyrotomy

6.6 Tracheotomy

6.7 Pediatric patients

7 Complications

8 See also

9 References

10 Bibliography

11 External links

History

Pre-19th century

See also: Tracheotomy

Tracheotomy was first depicted on Egyptian artifacts in 3600 BCE.[1]

It

was described in the Rigveda, a Hindi text, circa 2000 BCE.[1]

Homerus

of Byzantium is said to have written of Alexander the Great saving a

soldier from suffocation in 1000 BCE by making an incision with the tip

of his sword in the man's trachea.[1]

Hippocrates condemned the practice

of tracheotomy. Warning against the unacceptable risk of death from

inadvertent laceration of the carotid artery during tracheotomy, he

instead advocated the practice of tracheal intubation.[2]

Because surgical

instruments were not sterilized at that time, infections following surgery

also produced numerous complications, including dyspnea, often leading

to death.[3]

Despite the concerns of Hippocrates, it is believed that an early

tracheotomy was performed by Asclepiades of Bithynia, who lived in

Rome around 100 BCE. Galen and Aretaeus, both of whom lived in

Rome in the second century AD, credit Asclepiades as being the first

physician to perform a non-emergency tracheotomy.[citation needed]

Antyllus, another Roman physician of the second century AD, supported

tracheotomy when treating oral diseases. He refined the technique to be more similar to that used in modern

times, recommending that a transverse incision be made between the third and fourth tracheal rings for the

treatment of life-threatening airway obstruction.[2]

Antyllus (whose original writings were lost but not before


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they were preserved by the Greek historian Oribasius) wrote that tracheotomy was not effective however in

cases of severe laryngotracheobronchitis because the pathology was distal to the operative site.[3]

In AD 131,

Galen clarified the anatomy of the trachea and was the first to demonstrate that the larynx generates the

voice.[citation needed]

By AD 700, the tracheotomy was well described in Indian and Arabian literature, although it was rarely

practiced on humans.[3]

Circa AD 1020, Avicenna described tracheal intubation in The Canon of Medicine in

order to facilitate breathing.[4]

The first correct description of the tracheotomy operation for treatment of

asphyxiation was described by Ibn Zuhr in the 12th century,[5]

From 1500 to 1833 there are only 28 known reports of successful tracheotomy.[6]

Although the Renaissance

saw significant advances in science and surgery, and surgeons became increasingly open to experimental

surgery on the trachea, nevertheless the mortality rate failed to improve.[6]

The next known report on

tracheal intubation and subsequent artificial respiration of animals was in 1543, when Andreas Vesalius

pointed out that the technique could be life-saving.[citation needed]

The next known report of human

tracheotomy was in 1546, performed on a patient suffering from complications of a peritonsillar abscess; this

patient apparently made a complete recovery.[2]

In the late 16th century, anatomist Hieronymus Fabricius

described a useful technique in his writings, although he had never actually performed a tracheotomy. He

advised using a vertical incision and a straighter, shorter cannula that would prevent the tube from advancing

too far into the trachea. He counseled that the operation should be performed only as a last option.[3]

The

first tracheotomy to be described on a pediatric patient was in 1620, after a boy began to ashyxiate on a bag

of gold he had swallowed. The object became lodged in his esophagus, obstructing his trachea. The

tracheotomy allowed the surgeon to manipulate the bag so that it passed through his alimentary tract,

apparently with no further sequelae.[3]

19th century

See also: Endoscopy

In the early 19th century, the tracheotomy finally began to be recognized as a legitimate means of treating

severe airway obstruction. In 1832, French physician Pierre Bretonneau employed it as a last resort to treat a

case of diphtheria.[7]

In 1852, Bretonneau's student Armand Trousseau reported a series of 169

tracheotomies (158 of which were for croup, and 11 for "chronic maladies of the larynx")[8]

Trousseau's

claimed 73% mortality rate was hailed as "very satisfying".[3]

If the procedure is delayed until the patient is

close to death, the body will have already incurred major damage due to anoxia. Despite this, surgeons

continued to postpone the tracheotomy until it was too late to be effective. In 1869, the German surgeon

Friedrich Trendelenburg reported the first successful elective human tracheotomy to be performed for the

purpose of administration of general anesthesia.[citation needed]

In 1878, the Scottish surgeon William

Macewen reported the first orotracheal intubation.[citation needed]

At last, in 1880 Morrell Mackenzie's book

discussed the symptoms indicating a tracheotomy and when the operation is absolutely necessary.[2]

While all these surgical advances were taking place, many important developments were also taking place in

the science of optics. Many new optical instruments with medical applications were invented during the 19th

century. In 1805, German physician Philipp von Bozzini used a device he invented and called the lichtleiter

(or light-guiding instrument) to examine the human urinary bladder, rectum, nasopharynx and

laryngopharynx.[9][10]

The practice of gastric endoscopy in humans was pioneered by United States Army

surgeon William Beaumont in 1822 with the cooperation of his patient Alexis St. Martin, a victim of an

accidental gunshot wound to the stomach.[11]

In 1853, Antoine Jean Desormeaux of France examined the

human bladder using a device he invented and called the endoscope (this was the first time this term was

applied to this practice).[citation needed]

In 1854, a singing teacher named Manuel Garcia became the first man


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to view the functioning glottis in its entirety. Garcia developed a tool that used two mirrors for which the sun

served as an external light source.[12]

Using this device, he was able to observe the function of his own

glottic apparatus and the uppermost portion of his trachea. His findings were presented at the Royal Society

of London in 1855.[10]

In 1868, Adolph Kussmaul of Germany performed the first

esophagogastroduodenoscopy on a living human. The subject was a sword-swallower, who swallowed a

metal tube with a length of 47 centimeters and a diameter of 13 millimeters.[citation needed]

On 2 October

1877, Berlin physician Maximilian Nitze and instrument maker Josef Leiter introduced the

cystourethroscope[13]

and in 1881, Polish physician Jan Mikulicz-Radecki created the first rigid gastroscope

for practical applications.[14][15][16]

All previous observations of the glottis and larynx had been performed

under indirect vision (using mirrors) until 23 April 1895, when Alfred Kirstein of Germany first described

direct visualization of the vocal cords. Kirstein performed the first direct laryngoscopy in Berlin, using an

esophagoscope he had modified for this purpose; he called this device an autoscope.[17]

It is believed that the

death in 1888 of Kaiser Frederick from laryngeal cancer motivated Kirstein to develop the autoscope. [18]

20th century

The 20th century saw the transformation of the practices of endoscopy and tracheal intubation from rarely

employed procedures to essential components of the practices of anesthesia, critical care medicine,

emergency medicine, gastroenterology, pulmonology, and surgery. Until 1913, surgery involving the mouth

and nose was performed by mask inhalation anesthesia, topical application of local anesthetics to the mucosa,

rectal anesthesia, or intravenous anesthesia. While otherwise effective, these techniques did not protect the

airway from obstruction and also exposed patients to the risk of aspiration of blood and mucus into the

tracheobronchial tree. In 1913, Chevalier Jackson, a professor of laryngology at Jefferson Medical College in

Philadelphia, Pennsylvania, was the first to report a high rate of success for the use of direct laryngoscopy in

orotracheal intubation.[19]

Jackson introduced a new laryngoscope blade that had a light source at the distal

tip, rather than the proximal light source used by Kirstein.[20]

This new blade incorporated a component that

the operator could slide out to allow room for passage of an endotracheal tube or bronchoscope.[9][20]

That same year, Henry Janeway published results he had achieved using another new laryngoscope he had

recently developed.[21]

An American anesthesiologist practicing at Bellevue Hospital in New York City,

Janeway believed that direct intratracheal insufflation of volatile anesthetics would provide improved

conditions for surgery of the nose, mouth and throat. With this in mind, he developed a laryngoscope

designed for the sole purpose of tracheal intubation. Similar to Jackson's device, Janeway's instrument

incorporated a distal light source. Unique however was the inclusion of batteries within the handle of the

laryngoscope. Additional features included a central notch for maintaining the tracheal tube in the midline of

the oropharynx during intubation, and a slight curve to the distal tip of the blade to help guide the tube

through the glottis. The success of this design led to its subsequent use in other types of surgery in addition to

surgery of the nose, mouth and throat. Janeway was instrumental in popularizing the widespread use of direct

laryngoscopy and tracheal intubation in the practice of anesthesiology.

After World War I, further advances were made in the field of intratracheal anesthesia. Perhaps most notable

among these were those made by Sir Ivan Whiteside Magill (1888–1986). Working with Sir Harold Gillies (a

surgeon) and E. Stanley Rowbotham (an anesthetist), Magill developed the technique of awake blind

nasotracheal intubation.[22][23][24][25][26][27]

In 1920, Magill devised a new type of angulated forceps (the

Magill forceps) that are still used today to facilitate nasotracheal intubation in a manner that is little changed

from Magill's original technique.[28]

Robert Macintosh also achieved significant advances in techniques for tracheal intubation when he

introduced his new curved laryngoscope blade in 1943.[29]

The Magill curve of an endotracheal tube and the

Magill forceps for positioning the tube during nasotracheal intubation are named after Magill, while the most

widely used curved laryngoscope blade is named after Macintosh.[30]

In 1932, Rudolph Schindler of


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Germany introduced the first semi-flexible gastroscope.[31]

This device had numerous lenses positioned

throughout the tube and a miniature light bulb at the distal tip. The tube of this device was 75 centimeters in

length and 11 millimeters in diameter, and the distal portion was capable of a certain degree of flexion.

Between 1945 and 1952, optical engineers (notably Karl Storz of Germany, Harold Hopkins of England, and

Mutsuo Sugiura of the Japanese Olympus Corporation) built upon this early work, leading to the development

of the first gastrocamera.[32]

In 1964, Fernando Alves Martins of Portugal applied optical fiber technology to

one of these early gastrocameras to produce the first gastrocamera with a flexible fiberscope.[33][34]

Initially

used in esophagogastroduodenoscopy, newer devices were developed in the late 1960s for use in

bronchoscopy, rhinoscopy, and laryngoscopy. The concept of using a fiberoptic endoscope for tracheal

intubation was introduced by Peter Murphy in 1967.[35]

By the mid-1980s, the flexible fiberoptic

bronchoscope had become an indispensable instrument within the pulmonology and anesthesia communities.

In the early 20th century, physicians began to use the tracheotomy in the treatment of patients afflicted with

paralytic poliomyelitis who required mechanical ventilation. The currently used surgical tracheotomy

technique was described in 1909 by Chevalier Jackson.[36]

However, surgeons continued to debate various

aspects of the tracheotomy well into the 20th century. Many techniques were described and employed, along

with many different surgical instruments and tracheal tubes. Surgeons could not seem to reach a consensus

on where or how the tracheal incision should be made, arguing whether the "high tracheotomy" or the "low

tracheotomy" was more beneficial. Ironically, the newly developed inhalational anesthetic agents and

techniques of general anesthesia actually seemed to increase the risks, with many people suffering fatal

postoperative complications. Jackson emphasised the importance of postoperative care, which dramatically

reduced the death rate. By 1965, the surgical anatomy was thoroughly and widely understood, antibiotics

were widely available and useful for treating postoperative infections, and other major complications of

tracheotomy had also become more manageable. The current perioperative mortality rate for tracheotomy is

less than 1%.[37][38]

21st century

The "digital revolution" has brought newer technology to the art and science of tracheal intubation. Several

manufacturers have developed video laryngoscopes which employ digital technology such as the CMOS

active pixel sensor (CMOS APS) to generate a view of the glottis so that the trachea may be intubated. The

Glidescope video laryngoscope is one example of such a device.[39][40]

Indications

Tracheal intubation (orotracheal, nasotracheal, cricothyrotomy, or tracheotomy) is indicated under any of the

following circumstances:[41]

Comatose or intoxicated patients with a depressed level of consciousness who are unable to protect

their airways. This is commonly defined as those subjects with a Glasgow Coma Scale ≤ 8. In such

cases, the throat muscles may lose their tone so that the hypopharynx becomes obstructed, impeding

the free flow of air into the lungs. Furthermore, protective airway reflexes such as coughing and

swallowing, which serve to protect the airways against aspiration of secretions and foreign bodies, may

be absent. With tracheal intubation, airway patency is restored and the lower airways can be protected

from aspiration.

Requirement for mechanical ventilation, including cardiopulmonary resuscitation and general

anesthesia. In such situations, spontaneous ventilation may be decreased or absent due to the effect of

injury, disease, anesthetic agents, opioids, or neuromuscular-blocking drugs. To enable mechanical

ventilation, a tracheal tube is often used, although there are alternative devices such as the laryngeal

mask airway[42]

or the CPAP mask.

Apnea or hypoventilation (e.g., closed head injury, intoxication or poisoning, cervical spine injury, flail

chest)


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Persistent or recurrent airway obstruction

Impending or potential compromise of the airway (e.g., sustained seizure activity, facial fractures,

expanding neck hematoma, laryngeal or tracheobronchial injury, airway burns, inhalation injury)

Inability to maintain oxygenation using face mask oxygen supplementation (severe pneumonia, acute

respiratory distress syndrome (ARDS), near-drowning, etc.)

Diagnostic or therapeutic manipulation of the airway (such as bronchoscopy, laser therapy or stenting

of the bronchi).

Predicting difficulty of tracheal intubation

All persons performing tracheal intubation must be familiar with alternative techniques of securing the

airway. Because the life of a patient can depend on the success of tracheal intubation, it is important to

assess possible obstacles beforehand. The history is helpful in this respect. The diagnosis and/or proposed

surical procedure may offer clues to a potentially difficult airway. The subject should be questioned about

any significant signs or symptoms, such as dysphonia or dyspnea. Such findings may suggest obstructing

lesions in various locations within the pharynx, larynx, or tracheobronchial tree. It is also important to elicit

any history of previous surgery (e.g., previous cervical fusion), trauma, radiation therapy, or tumors involving

the head, neck, and mediastinum, as well as any prior experiences with tracheal intubation (especially prior

tracheotomy).

A detailed physical examination is also critical to evaluation of the airway. Specifically, one should evaluate:

the range of motion of the cervical spine: the subject should be able to tilt the head back and then

forward so that the mentum touches the chest.

1.

the range of motion of the temporomandibular joint: three of the subject's fingers should be able to fit

between the upper and lower incisors.

2.

the size and shape of the maxilla and mandible, looking especially for problems such as maxillary

hypoplasia, prominent maxillary incisors or retrognathia.

3.

the thyromental distance: three of the subject's fingers should be able to fit between the thyroid

cartilage and the mentum.

4.

the size and shape of the tongue and palate relative to the size of the oral cavity:5.

the teeth, especially noting the presence of any loose or damaged teeth or crowns.6.

Besides the physical examination, many classification systems have been developed in an effort to predict

difficulty of tracheal intubation, including the Cormack-Lehane grading system,[43][44]

the Intubation

Difficulty Scale (IDS),[45]

and the Mallampati score.[46]

The Mallampati score is determined by looking at

the anatomy of the mouth and based on the visibility of the base of uvula, faucial pillars and the soft palate.

Such medical scoring systems correlate to some extent with the degree of difficulty of laryngoscopy and

tracheal intubation, and may aid in the evaluation of factors linked to difficult tracheal intubation. It should

however be noted that no single score or combination of scores can be trusted to detect all patients who are

difficult to intubate. No system has yet been devised that can claim 100% positive predictive value, or 100%

sensitivity and specificity. Furthermore, one recent study has demonstrated that even among experienced

anesthesiologists, only 25% could correctly define all four grades of the widely used Cormack–Lehane

classification system, and intra-observer reliability (reproducibility of results) was poor.[47]

While perfection

may be an unrealistic expectation from a statistical standpoint, the grave consequences of failed tracheal

intubation require the highest possible degree of certainty in predicting the difficulty of intubation.

Equipment

Laryngoscopes

Main article: Laryngoscope


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Laryngoscope handles with an assortment of

Miller blades (large adult, small adult, pediatric,

infant, and neonate).

Laryngoscope handle with an assortment of

Macintosh blades (large adult, small adult,

pediatric).

An endotracheal tube stylet, useful in facilitating

orotracheal intubation.

The

vast

majority of tracheal intubations involve the use of a

"scope" of one type or another. Since its introduction by

Kirstein in 1895, the most common device used for this

purpose has been the conventional laryngoscope. Today, the typical conventional laryngoscope consists of a

handle, usually containing batteries, and a set of interchangeable blades. Two basic styles of laryngoscope

blade are commercially available: the straight blade and the curved blade. The Macintosh blade is the most

widely used of the curved laryngoscope blades,[30]

while the Miller blade[48]

is the most popular style of

straight blade.[49]

There are many other styles of straight and curved blades (e.g., Phillips, Robertshaw,

Sykes, Wisconsin, Wis-Hipple, etc.) with accessories such as mirrors for enlarging the field of view and even

ports for the administration of oxygen. These specialty blades are primarily designed for use by anesthetists,

most commonly in the operating room.

Besides the conventional laryngoscopes, many other devices have been developed as alternatives to direct

laryngoscopy. These include a number of indirect fiberoptic viewing laryngoscopes such as the flexible

fiberoptic bronchoscope, Bullard scope,[50]

UpsherScope,[51][52]

and the WuScope.[53]

These devices are

widely employed for tracheal intubation, especially in the setting of the difficult intubation (see below).

Several types of video laryngoscopes are also currently available, such as the Glidescope,[39][40]

McGrath

laryngoscope,[54]

Daiken Medical Coopdech C-scope VLP-100,[55]

the Storz C-Mac,[56]

Pentax AWS[57]

[58][59][60] and the Berci DCI

[61]. Other "noninvasive" devices which are commonly employed for tracheal

intubation are the laryngeal mask airway[42]

(used as a guide for endotracheal tube placement), the lighted

stylet,[62]

and the AirTraq.[63]

Due to the widespread availability of such devices, the technique of blind

digital intubation[64]

of the trachea is rarely practiced today, though it may still be useful in emergency

situations under austere conditions such as natural or man-made disasters.

Stylets

An intubating stylet is a malleable metal wire which can

be inserted into the endotracheal tube to make the tube

conform better to the laryngopharyngeal anatomy of the

specific individual, thus facilitating its insertion. It is

commonly employed under circumstances of difficult

laryngoscopy. Just as with laryngoscope blades, there are

also several types of available stylets. The Verathon

Stylet is a rigid stylet that is curved to follow the 60°

angulation of the blade of the GlideScope® video


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Diagram of an endotracheal tube (blue, A; Cuff inflation

tube B) that has been inserted into the airway (C) of a

patient. D: Esophagus

laryngoscope.[39]

The Eschmann tracheal tube introducer (often referred to as a gum elastic bougie) is another specialized type

of stylet, which can also be used to facilitate difficult intubation.[65][66]

This flexible device is 60 cm in

length, 15 French (5 mm diameter) with a small "hockey-stick" angle at its distal tip. Unlike the stylet, the

Eschmann tracheal tube introducer is typically inserted directly into the trachea and then used as a guideover

which the endotracheal tube can be passed (in a manner analogous to the Seldinger technique). As the

Eschmann tracheal tube introducer is considerably less rigid than a conventional stylet, this technique is

considered to be a relatively atraumatic means of tracheal intubation.

The concept of using a stylet for replacing or exchanging orotracheal tubes was introduced by Finucane and

Kupshik in 1978, using a central venous catheter.[67]

The modern tracheal tube exchanger is a hollow

catheter, 56-81 cm in length, that can be used for removal and replacement of tracheal tubes without the

need for laryngoscopy.[68]

The Cook Airway Exchange Catheter (CAEC) is another example of this type of

catheter.[69]

Tracheal tubes

Tracheal tubes are commonly used for airway

management in the settings of general anesthesia,

critical care, mechanical ventilation, and

emergency medicine. They may also be used as

an alternative route for many medications, in the

event an intravenous infusion cannot be

established. The tube is inserted into the trachea

in order to ensure that the airway is not closed off

and that air is able to reach the lungs. The

tracheal tube is regarded as the most reliable

available method for protecting a patient's

airway.

Sir Ivan Whiteside Magill (1888–1986) was an

Irish born anesthetist who is famous for his

involvement in much of the innovation and

development in modern anesthesia. Originally a general practitioner, he accepted a post at the Queen's

Hospital, Sidcup in 1919 as an anesthetist. The hospital had been established for the treatment of facial

injuries sustained in the World War I. Working with plastic surgeon Harold Gillies, he was responsible for the

development of numerous items of anesthetic equipment but most particularly the single-tube technique of

endotracheal anesthesia. This was driven by the immense difficulties of administering "standard" anesthetics

such as chloroform and ether to men with severe facial injury using masks; they would cover the operative

field. Following the closure of the hospital, and the diminishing numbers of patients seen from the war era, he

continued to work with Gillies in private practice but was also appointed to the Westminster Hospital and

Brompton Hospital in London. He was Knighted by Queen Elizabeth II in 1960.

The original tubes were cut from a roll of rubber industrial tubing by his assistant, hence the natural curve of

the tube. A curved metal adaptor was designed (Magill oral & nasal connectors) and a 4" black rubber

connecting hose to fit to the anesthetic circuit was adapted from an MG brake hose and named the 'catheter

mount' by Magill's theatre technician at Westminster Hospital. Originally, there was no inflatable cuff, the

tube was packed either side of the sub-glottis by two green anesthetic swabs, with ribbon gauze sewn on by

hand to aid extraction at extubation of the trachea. Anesthetic gel or ointment was used to lubricate the tube

and provide some relief for the patient's throat soreness after the procedure.


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A typical cuffed endotracheal tube, constructed

of polyvinyl chloride.

A Carlens double-lumen endotracheal tube,

commonly used for thoracic surgical operations

such as VATS lobectomy.

Portex Medical (England and France) produced the first

cuffless plastic 'Ivory' tracheal tubes, in conjunction with

Magill's design later adding a cuff as manufacturing

techniques became more viable, these were glued on by

hand to make the famous Blue-line tube copied by many

other manufacturers. Mallinckrodt GmBH developed the

disposable endotracheal tube and produced a plethora of

design variations, adding the 'Murphy Eye' to their tubes

in case of 'accidental' placement of the tube to avoid right

bronchial occlusion. David S. Sheridan was one of the

manufacturers of the American markets "disposable"

plastic endotracheal tube now used routinely in surgery.

Previously, red rubber (Rusch-Germany) tubes were

used, then sterilized for re-use.

Tracheal intubation usually requires general anesthesia

and muscle relaxation but can be achieved in the awake patient with local anesthesia or in an emergency

without any anesthesia, although this is extremely uncomfortable. It is usually performed by visualising the

glottis by means of a hand-held laryngoscope that has a variety of curved and straight blades, with a light

source. Intubation can also be performed using a flexible fiberoptic bronchoscope, video laryngoscope, or

simply with the use of the attendant's fingers (this technique is referred to as blind digital intubation). The

goal is to position the end of the tracheal tube two centimeters above the bifurcation of the lungs or the

carina. If inserted too far into the trachea it often goes into the right main bronchus (because the right main

brochus is less angled than the left.

Most tracheal tubes today are constructed of polyvinyl chloride, but specialty tubes constructed of silicone

rubber, latex rubber, or stainless steel are also widely available. Most tubes have an inflatable cuff to seal the

trachea and bronchial tree against air leakage and aspiration of gastric contents, blood, secretions, and other

fluids. Uncuffed tubes are also available, though their use is limited mostly to pediatric patients (in small

children, the cricoid cartilage, the narrowest portion of the pediatric airway, often provides an adequate seal

for mechanical ventilation).

Types of tracheal tube include oral or nasal, cuffed or

un-cuffed, preformed (e.g. RAE tube), reinforced tubes,

double-lumen tubes and tracheostomy tubes. For human

use, tubes range in size from 2-10.5 mm in internal

diameter (ID). The size is chosen based on the patient's

body size, with the smaller sizes being used for pediatric

and neonatal patients. Tubes larger than 6 mm ID usually

have an inflatable cuff. Originally made from red rubber,

most modern tubes are made from polyvinyl chloride.

Those placed in a laser field may be flexometallic.

Robertshaw (and others) developed double-lumen

endo-bronchial tubes for intra-thoracic surgery. These

allow single-lung ventilation whilst the other lung is

collapsed to make surgery easier. The deflated lung is

re-inflated as surgery finishes to check for fistulas (tears).

Another type of endotracheal tube has a small second

lumen opening above the inflatable cuff, which can be

used for suction of the nasopharngeal area and above the cuff to aid extubation (removal). This allows

suctioning of secretions which sit above the cuff which helps reduce the risk of chest infections in long-term

intubated patients. A shortened tube, a tracheostomy tube, can be inserted through an opening in the neck (a

tracheostomy) into the trachea. This is often a temporary stoma, but patients can live with them permanently.


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The "armored" endotracheal tubes are cuffed, wire-reinforced, silicone rubber tubes which are quite flexible

but yet difficult to compress or kink. This can make them useful for situations in which the trachea is

anticipated to remain intubated for a prolonged duration, or if the neck is to remain flexed during surgery.

Polyvinyl chloride tubes are relatively stiff in comparison. Preformed tubes (such as the oral and nasal RAE

tubes, named after the inventors Ring, Adair and Elwyn) are also widely available for special applications.

These may also be constructed of polyvinyl chloride or wire-reinforced silicone rubber. Other tubes (such as

the Bivona® Fome-Cuf® tube) are designed specifcally for use in laser surgery in and around the airway.

Various types of double-lumen endotracheal (actually, endobronchial) tubes have been developed

(Carlens,[70]

White, Robertshaw, etc.) for ventilating each lung independently—this is useful during

pulmonary and other thoracic operations.

A tracheostomy tube is a 2-3 inch-long curved metal or plastic tube that may be inserted into a tracheostomy

stoma to maintain patency of the lumen. Several types of tracheostomy tube are available, depending on the

requirements of the patient, including Shiley, Bivona (a silicon tube with metal rings that are good for airways

with damage to the tracheal rings or otherwise not straight), and fenestrated.

A tracheal button is a rigid plastic cannula about 1 inch in length that can be placed into the tracheostomy

after removal of a tracheostomy tube, to maintain patency of the lumen. It is generally used in people with

obstructive sleep apnea, who wear it during during waking hours and remove it while sleeping to ensure a

patent airway and reduce the risk of asphyxiation. Since the tube does not extend far into the trachea, it is

easy to breathe and speak with the device in place.

Methods to confirm tube placement

No single method for confirming tracheal tube placement has been shown to be 100% reliable. Accordingly,

the use of multiple methods for confirmation of correct tube placement is now widely considered to be the

standard of care. Such methods include direct visualization of the tip of the tube as it passes through the

glottis. Additionally, one should be able to hear equal bilateral breath sounds on auscultation of the chest, and

no sound upon auscultation of the epigastrium. Equal bilateral rise and fall of the chest wall should be evident

with ventilatory excursions. A small amount of water vapor should also be evident within the lumen of the

tube with each exhalation, and there should be no gastric contents in the tube at any time.

Ideally, at least one of the methods utilized for confirming tracheal tube placement should be an instrument.

Waveform capnography has emerged as the gold standard for the confirmation of tube placement within the

trachea. Other methods relying on instruments include the use of a colorimetric end-tidal carbon dioxide

detector, a self-inflating esophageal bulb, or an esophageal detection device.[71]

Pulse oximetry is also widely

used as a tertiary confirmation measure, but this technique has important limitations, most notably a

significant delay in the decrease in oxygen saturation, especially if the subject has been pre-oxygenated.

Tracheal tube maintenance

The tube is secured in place with tape or a tracheal tube holder. A cervical collar is sometimes used to

prevent motion of the airway. Tube placement should be confirmed after each physical move of the patient

and after any unexplained change in his/her clinical status. Continuous pulse oximetry and continuous

waveform capnography are often used to monitor the tube's correct placement.

An excessive leak can sometimes be corrected through the placement of a larger (0.5 mm larger in internal

diameter) tracheal tube, and in difficult-to-ventilate pediatric patients children it is often necessary to use

cuffed tubes to allow for high pressure ventilation if the leak is too great to overcome with the ventilator.[72]

Special situations


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Emergency intubation

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 oropharyngeal airway,

and the Combitube.[73]

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.

Rapid-sequence intubation

Rapid-sequence intubation (RSI) refers to the method of sedation and paralysis prior to tracheal intubation.

This technique is quicker than the process normally used to induce a state of general anesthesia. One

important difference between RSI and routine tracheal intubation is that the practitoner does not ventilate the

lungs after administration of a rapid-acting neuromuscular blocking agent. Another key feature of RSI is the

application of manual pressure to the cricoid cartilage (this is referred to as the Sellick maneuver) prior to

instrumentation of the airway and intubation of the trachea.

RSI involves pre-oxygenating the patient with a tightly-fitting oxygen mask, followed by the sequential

administration of pre-determined doses of a hypnotic drug and a rapid-acting neuromuscular blocker.

Hypnotics used include thiopental, propofol and etomidate. Neuromuscular-blocking drugs used include

suxamethonium (sometimes with a defasciculating dose of vecuronium) and rocuronium.[1] Other drugs may

be used in a "modified" RSI. When performing endotracheal intubation, there are several adjunct medications

available. No adjunctive medications, when given for their respective indications, have been proven to

improve outcomes.[2] Opioids such as alfentanil or fentanyl may be given to attenuate the responses to the

intubation process (tachycardia and raised intracranial pressure). This is supposed to have advantages in

patients with ischemic heart disease and those with intra-cerebral hemorrhage (e.g. after traumatic head

injury or stroke). Lidocaine is also theorized to blunt a rise in intracranial pressure during laryngoscopy,

although this remains controversial and its use varies greatly. Atropine may be used to prevent a reflex

bradycardia from vagal stimulation during laryngoscopy, especially in young children and infants.

Nasotracheal intubation


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Nasotracheal intubation

Difficult intubation

Many individuals have unusual airway anatomy, such as those who have

limited range of motion of the cervical spine or temporomandibular joint,

or who have oropharyngeal tumors, hematomas, angioedema,

micrognathia, retrognathia, or excess adipose tissue of the face and neck.

Using conventional laryngoscopic techniques, intubation of the trachea

can be difficult in such people. Use of the flexible fiberoptic

bronchoscope and similar devices has become among the preferred

techniques in the management of such cases. Among the drawbacks of

these devices are their high cost of purchase, maintenance and repair.[74][75]

Another drawback is that intubation with one of these devices

can take considerably longer than that achieved using conventional

laryngoscopy; this limits their use somewhat in urgent and emergent

situations.

Cricothyrotomy

Main article: Cricothyrotomy

A cricothyrotomy is an incision made through the skin and 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. 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.[76]

However, while

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. In practice, it is little better than apneic

oxygenation inasmuch as the small diameter of these devices allows for adequate oxygenation but not for

elimination of carbon dioxide (ventilation). After one hour of apneic oxygenation through a cricothyrotomy,

one can expect a PaCO2 of greater than 250 millimeters of mercury and an arterial pH of less than 6.72,

despite an oxygen saturation of 98% or greater.[77]

Tracheotomy

Main article: Tracheotomy

Pediatric patients

Most of the general principles of anesthesia can be applied to children, but there are some significant

anatomical and physiological differences between children and adults that can cause problems, especially in

neonates and children weighing less than 15 kg. For infants and young children, oral intubation is easier than

nasal. Nasal route carries risk of dislodgement of adenoid tissue and epistaxis, but advantages include good

fixation of tube. Because of good fixation, nasal route is preferable to oral route in children undergoing

intensive care and requiring prolonged intubation. The position of the tube is checked by auscultation (equal

air entry on each side and, in long-term intubation, by chest X-ray). Because the airway of a child is narrow,

a small amount of oedema can produce severe obstruction. Edema can easily be caused by forcing in a

tracheal tube that is too tight. (If length of the tube is suspected to be large, immediate changing it to the

smaller size is suggestible.)

The appropriate length for the endotracheal tube can be estimated by doubling the distance from the corner

of the child's mouth to the ear canal. The tip of the tube should be at midtrachea, between the clavicles on an


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AP chest X-ray. The correct diameter of the tube is that which results in a small leak at a pressure of about

25 cm of water. The appropriate inner diameter for the endotracheal tube is roughly the same diameter as the

child's little finger. For normally nourished children 2 years of age and older, the internal diameter of the tube

can be calculated using the following formula:

Internal diameter of tube (mm) = (patient's age in years + 16) / 4

For neonates, 3 mm internal diameter is accepted while for premature infants 2.5 mm internal diameter is

more appropriate.

Complications

Tracheal intubation is an invasive procedure that requires a great deal of clinical experience to master.[78]

When performed improperly (e.g., unrecognized esophageal intubation), the associated complications may be

rapidly fatal.[79]

Consequently, in recent editions of its Guidelines for Cardiopulmonary Resuscitation the

American Heart Association has de-emphasized the role of tracheal intubation in advanced airway

maintenance, in favor of more basic techniques like bag-valve-mask ventilation.[80]

Despite these concerns,

tracheal intubation is still considered the definitive technique for airway management, as it allows the most

reliable means of oxygenation and ventilation, while providing the highest level of protection against vomitus

and regurgitation.

Although the conventional laryngoscope has proven effective across a wide variety of settings and patients,

its use and misuse can result in serious complications (e.g., trauma to oropharyngeal and dental structures).

Newer technologies such as flexible fiberoptic laryngoscopy have fared better in reducing the incidence of

such complications, though the most common cause of intubation trauma remains a lack of skill on the part of

the laryngoscopist.

Even when properly performed, significant complications may result as a result of tracheal intubation,

especially for prolonged duration. Such complications include dental trauma, vocal cord paresis,

tracheoinnominate fistula, tracheomalacia, tracheoesophageal fistula, or even frank rupture of the trachea.

The cuff pressure must be monitored carefully in order to avoid complications from over-inflation, many of

which can be traced to excessive cuff pressure causing ischemia of the tracheal mucosa.[81]

See also

Jet ventilation

Positive end-expiratory pressure

Positive pressure ventilation

References

^ a b c Steven E. Sittig and James E. Pringnitz (February 2001). "Tracheostomy: evolution of an airway"

(http://www.tracheostomy.com/resources/pdf/evolution.pdf) . AARC Times: 48–51.

http://www.tracheostomy.com/resources/pdf/evolution.pdf . Retrieved 25 July 2010.

1.

^ a b c d Alfio Ferlito, Alessandra Rinaldo, Ashok R. Shaha, Patrick J. Bradley (December 2003). "Percutaneous

Tracheotomy" (http://www.informaworld.com/smpp/content~db=all~content=a713714394) . Acta

Otolaryngologica 123 (9): 1008–1012. doi:10.1080/00016480310000485 (http://dx.doi.org

/10.1080%2F00016480310000485) . PMID 14710900 (http://www.ncbi.nlm.nih.gov/pubmed/14710900)

. http://www.informaworld.com/smpp/content~db=all~content=a713714394 . Retrieved 25 July 2010.

2.

^ a b c d e f O. Rajesh & R. Meher (2006). "Historical Review Of Tracheostomy" (http://www.ispub.com/journal

/the_internet_journal_of_otorhinolaryngology/volume_4_number_2_33/article

/historical_review_of_tracheostomy.html) . The Internet Journal of Otorhinolaryngology 4 (2).

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