Tracheotomy

This article is about the surgical procedure called a tracheotomy. For a similar procedure, see Cricothyrotomy.

Tracheotomy
Intervention
Completed tracheotomy: 1 - Vocal folds 2 - Thyroid cartilage 3 - Cricoid cartilage 4 - Tracheal rings 5 - Balloon cuff
ICD-10-PCS	0B110F4
ICD-9-CM	31.1
MeSH	D014140

Among the oldest described surgical procedures, tracheotomy (also referred to as pharyngotomy, laryngotomy, and tracheostomy) consists of making an incision on the anterior aspect of the neck and opening a direct airway through an incision in the trachea. The resulting stoma can serve independently as an airway or as a site for a tracheostomy tube to be inserted; this tube allows a person to breathe without the use of his or her nose or mouth. Both surgical and percutaneous techniques are widely used in current surgical practice.

Etymology and terminology

The etymology of the word tracheotomy comes from two Greek words: the root tom- meaning "to cut", and the word trachea.^[1] The word tracheostomy, including the root stom- meaning "mouth," refers to the making of a semi-permanent or permanent opening, and to the opening itself. Some sources offer different definitions of the above terms. Part of the ambiguity is due to the uncertainty of the intended permanence of the stoma at the time it is created.^[2]

Indications

In the acute setting, indications for tracheotomy include such conditions as severe facial trauma, head and neck cancers, large congenital tumors of the head and neck (e.g., branchial cleft cyst), and acute angioedema and inflammation of the head and neck. In the context of failed orotracheal or nasotracheal intubation, either tracheotomy or cricothyrotomy may be performed. In the chronic setting, indications for tracheotomy include the need for long-term mechanical ventilation and tracheal toilet (e.g. comatose patients, or extensive surgery involving the head and neck). In extreme cases, the procedure may be indicated as a treatment for severe Obstructive Sleep Apnea seen in patients intolerant of Continuous Positive Airway Pressure (CPAP) therapy.

Surgical instruments

Tracheostomy tube

As with most other surgical procedures, some cases are more difficult than others. Surgery on children is more difficult because of their smaller size. Difficulties such as a short neck and bigger thyroid glands make the trachea hard to open.^[3] There are other difficulties withpatients with irregular necks, the obese, and those with a large goitre. The many possible complications include hemorrhage, loss of airway, subcutaneous emphysema, wound infections, stomal cellulites, fracture of tracheal rings, poor placement of the tracheotomy tube, and bronchospasm".^[4]

By the late 19th century, some surgeons had become proficient in performing the tracheotomy. The main instruments used were:

“Two small scalpels, one short grooved director, a tenaculum, two aneurysm needles which may be used as retractors, one pair of artery forceps, haemostatic forceps, two pairs of dissecting forceps, a pair of scissors, a sharp-pointed tenotome, a pair of tracheal forceps, a tracheal dilator, tracheotomy tubes, ligatures, sponges, a flexible catheter, and feathers”.^[3] Haemostatic forceps were used to control bleeding from separated vessels that were not ligatured because of the urgency of the operation. Generally, they were used to expose the trachea by clamping the isthmus thyroid gland on both sides. To open the trachea physically, a sharp-pointed tentome allowed the surgeon easily to place the ends into the opening of the trachea. The thin points permitted the doctor a better view of his incision. Tracheal dilators, such as the “Golding Bird”, were placed through the opening and then expanded by “turning the screw to which they are attached.” Tracheal forceps, as displayed on the right , were commonly used to extract foreign bodies from the larynx. The optimum tracheal tube at the time caused very little damage to the trachea and “mucus membrane”.^[3]

The best position for a tracheotomy was and still is one that forces the neck into the biggest prominence. Usually, the patient was laid on his back on a table with a cushion placed under his shoulders to prop him up. The arms were restrained to ensure they would not get in the way later.^[3] The tools and techniques used today in tracheotomies have come a long way. The tracheotomy tube placed into the incision through the windpipe comes in various sizes, thus allowing a more comfortable fit and the ability to remove the tube in and out of the throat without disrupting support from a breathing machine. In today’s world general anesthesia is used when performing these surgeries, which makes it much more tolerable for the patient. Special tracheostomy tube valves (such as the Passy-Muir valve^[5] ) have been created to assist people in their speech. The patient can inhale through the unidirectional tube. Upon expiration, pressure causes the valve to close, redirecting air around the tube, past the vocal folds, producing sound.^[6]

The tracheotomy underwent centuries of denial and rejection as well as much failure. Finally, in recent decades, it has become a commonly accepted, crucial, and successful surgery that has saved the lives of hundreds of thousands of patients.

Percutaneous tracheotomy

While there were some earlier false starts, the first widely accepted Percutaneous Tracheotomy technique was described by Pat Ciaglia, a New York surgeon, in 1985. This technique involves a series of sequential dilatations using a set of seven dilators of progressively larger size.^[7] The next widely used technique was developed in 1989 by Bill Griggs, an Australian intensive care specialist. This technique involves the use of a specially modified pair of forceps with a central hole enabling them to pass over a guidewire enabling the performance of the main dilation in a single step.^[8] Since then a number of other techniques have been described. A variant of the original Ciaglia technique using a single tapered dilator known as a "blue rhino" is the most commonly used of these newer techniques and has largely taken over from the early multiple dilator technique. The Griggs and Ciaglia Blue Rhino techniques are the two main techniques in current use. A number of comparison studies have been undertaken between these two techniques with no clear differences emerging ^[9]

Complications

In order to limit the risk of damage to the recurrent laryngeal nerves (the nerves that control the vocal folds), tracheotomy is performed as high in the trachea as possible.^{[citation needed]} If only one of these nerves is damaged, the patient will experience dysphonia; if both of the nerves are damaged, the patient will experience complete aphonia.

A 2000 Spanish study of bedside percutaneous tracheostomy reported overall complication rates of 10–15% and a procedural mortality of 0%,^[10] which is comparable to those of other series reported in the literature from the Netherlands^[11][12] and the United States.^[13][14]

A 2003 American cadaveric study identified multiple tracheal ring fractures with the Ciaglia Blue Rhino technique as a complication occurring in 100% of their small series of cases.^[15] The comparative study above also identified ring fractures in 9 of 30 live patients^[9] while another small series identified ring fractures in 5 of their 20 patients.^[16] The long term significance of tracheal ring fractures is unknown.

Alternatives

Biphasic Cuirass Ventilation is a form of non-invasive mechanical ventilation that can in many cases allow patients an alternative mode of respiratory support, allowing patients to avoid an invasive tracheostomy and its many complications. While this method has not been proven to help in every case, it has been shown to be an effective alternative for many.

History

This portrait, though undated, supports the view that tracheotomy was practiced in ancient history.

Prior to 16th century

Tracheotomy was first depicted on Egyptian artifacts in 3600 BCE.^[17] It was described in the Rigveda, a Sanskrit text, circa 2000 BCE.^[17] Homerus of Byzantium is said to have written of Alexander the Great saving a soldier from suffocation by making an incision with the tip of his sword in the man's trachea.^[17] Hippocrates condemned the practice of tracheotomy as incurring an unacceptable risk of damage to the carotid artery. Warning against the possibility of death from inadvertent laceration of the carotid artery during tracheotomy, he instead advocated the practice of tracheal intubation.^[4] Because surgical instruments were not sterilized at that time, infections following surgery also produced numerous complications, including dyspnea, often leading to death.^[18]

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 2nd century AD, credit Asclepiades as being the first physician to perform a non-emergency tracheotomy. Antyllus, another Roman physician of the 2nd 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.^[4] Antyllus (whose original writings were lost but not before 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.^[18] In AD 131, Galen clarified the anatomy of the trachea and was the first to demonstrate that the larynx generates the voice.

By AD 700, the tracheotomy was well described in Indian and Arabian literature, although it was rarely practiced on humans.^[18] In 1000, Abu al-Qasim al-Zahrawi (936-1013), an Arab who lived in Arabic Spain, published the 30-volume Kitab al-Tasrif, the first illustrated work on surgery. He never performed a tracheotomy, but he did treat a slave girl who had cut her own throat in a suicide attempt. Al-Zahrawi (known to Europeans as Albucasis) sewed up the wound and the girl recovered, thereby proving that an incision in the larynx could heal. Circa AD 1020, Avicenna (980-1037) described tracheal intubation in The Canon of Medicine in order to facilitate breathing.^[19] The first correct description of the tracheotomy operation for treatment of asphyxiation was described by Ibn Zuhr (1091–1161) in the 12th century. Ibn Zuhr (also known as Avenzoar) successfully practiced the tracheotomy procedure on a goat, justifying Galen's approval of the operation.^[20]

16th-18th centuries

The European Renaissance brought with it significant advances in all scientific fields, particularly surgery. Increased knowledge of anatomy was a major factor in these developments. Surgeons became increasingly open to experimental surgery on the trachea. During this period, many surgeons attempted to perform tracheotomies, for various reasons and with various methods. Many suggestions were put forward, but little actual progress was made toward making the procedure more successful. The tracheotomy remained a dangerous operation with a very low success rate, and many surgeons still considered the tracheotomy to be a useless and dangerous procedure. The high mortality rate for this operation, which had not improved, supports their position.

From the period 1500 to 1832 there are only 28 known reports of tracheotomy.^[21] In 1543, Andreas Vesalius (1514–1564) wrote that tracheal intubation and subsequent artificial respiration could be life-saving. Antonio Musa Brassavola (1490–1554) of Ferrara treated a patient suffering from peritonsillar abscess by tracheotomy after the patient had been refused by barber surgeons. The patient apparently made a complete recovery, and Brassavola published his account in 1546. This operation has been identified as the first recorded successful tracheostomy, despite many ancient references to the trachea and possibly to its opening.^[21] Ambroise Paré (1510–1590) described suture of tracheal lacerations in the mid-16th century. One patient survived despite a concomitant injury to the internal jugular vein. Another sustained wounds to the trachea and esophagus and died.

Towards the end of the 16th century, anatomist and surgeon Hieronymus Fabricius (1533–1619) described a useful technique for tracheotomy in his writings, although he had never actually performed a the operation himself. He advised using a vertical incision and was the first to introduce the idea of a tracheostomy tube. This was a straight, short cannula that incorporated wings to prevent the tube from advancing too far into the trachea. He recommended the operation only as a last resort, to be used in cases of airway obstruction by foreign bodies or secretions. He counseled that the operation should be performed only as a last option.^[18] Fabricius' description of the tracheotomy procedure is similar to that used today. Julius Casserius (1561–1616) succeeded Fabricius as professor of anatomy at the University of Padua and published his own writings regarding technique and equipment for tracheotomy. Casserius recommended using a curved silver tube with several holes in it. Marco Aurelio Severino (1580–1656), a skillful surgeon and anatomist, performed multiple successful tracheotomies during a diphtheria epidemic in Naples in 1610, using the vertical incision technique recommended by Fabricius. He also developed his own version of a trocar.^[22]

In 1620 the French surgeon Nicholas Habicot (1550–1624), surgeon of the Duke of Nemours and anatomist, published a report of four successful "bronchotomies" which he had performed.^[23] One of these is the first recorded case of a tracheotomy for the removal of a foreign body, in this instance a blood clot in the larynx of a stabbing victim. He also described the first tracheotomy to be performed on a pediatric patient. A 14 year old boy swallowed a bag containing 9 gold coins in an attempt to prevent its theft by a highwayman. The object became lodged in his esophagus, obstructing his trachea. Habicot performed a tracheotomy, which allowed him to manipulate the bag so that it passed through the boy's alimentary tract, apparently with no further sequelae.^[18] Habicot suggested that the operation might also be effective for patients suffering from inflammation of the larynx. He developed equipment for this surgical procedure which displayed similarities to modern designs (except for his use of a single-tube cannula).

Sanctorius (1561–1636) is believed to be the first to use a trocar in the operation, and he recommended leaving the cannula in place for a few days following the operation.^[24] Early tracheostomy devices are illustrated in Habicot’s Question Chirurgicale^[23] and Julius Casserius' posthumous Tabulae anatomicae in 1627.^[25] Thomas Fienus (1567–1631), Professor of Medicine at the University of Louvain, was the first to use the word "tracheotomy" in 1649, but this term was not commonly used until a century later.^[26] Georg Detharding (1671–1747), professor of anatomy at the University of Rostock, treated a drowning victim with tracheostomy in 1714.^[27][28][29]

19th century

In the 1820s, the tracheotomy 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.^[30] 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")^[31] In 1858, John Snow was the first to report tracheotomy and cannulation of the trachea for the administration of chloroform anesthesia in an animal model.^[32] In 1871, the German surgeon Friedrich Trendelenburg (1844–1924) published a paper describing the first successful elective human tracheotomy to be performed for the purpose of administration of general anesthesia.^[33] In 1880, the Scottish surgeon William Macewen (1848–1924) reported on his use of orotracheal intubation as an alternative to tracheotomy to allow a patient with glottic edema to breathe, as well as in the setting of general anesthesia with chloroform.^[34][35] At last, in 1880 Morrell Mackenzie's book discussed the symptoms indicating a tracheotomy and when the operation is absolutely necessary.^[4]

20th century

In the early 20th century, physicians began to use the tracheotomy in the treatment of patients afflicted with paralytic poliomyelitis who required mechanical ventilation. 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. The currently used surgical tracheotomy technique was described in 1909 by Chevalier Jackson of Pittsburgh, Pennsylvania. 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 had also become more manageable.

See also

• Laryngotomy
• Cricothyrotomy

References

1. ^ Romaine F. Johnson (6 March 2003). "Adult Tracheostomy". Houston, Texas: Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine. http://www.bcm.edu/oto/grand/03_06_03.htm. ^{[dead link]}
2. ^ Jonathan P Lindman and Charles E Morgan (7 June 2010). "Tracheostomy". emedicine from WebMD. http://emedicine.medscape.com/article/865068-overview. 
3. ^ ^{a b c d} Wharton, Henry R. (January 1897). "Minor Surgery and Bandaging". American Journal of the Medical Sciences 113 (1): 104–106. doi:10.1097/00000441-189701000-00008. http://journals.lww.com/amjmedsci/Citation/1897/01000/Minor_Surgery_and_Bandaging.8.aspx. 
4. ^ ^{a b c d} Alfio Ferlito, Alessandra Rinaldo, Ashok R. Shaha, Patrick J. Bradley (December 2003). "Percutaneous Tracheotomy". Acta Otolaryngologica 123 (9): 1008–1012. doi:10.1080/00016480310000485. PMID 14710900. http://www.informaworld.com/smpp/content~db=all~content=a713714394. 
5. ^ Passy, Victor; Baydur, A., Prentice, W., & Darnell-Neal, R. (199). "Passy-muir® tracheostomy speaking valve on ventilator-dependent patients". Laryngoscope 103 (6): 653–658. 
6. ^ James H. Cullen (1 June 1963). "An Evaluation of Tracheostomy in Pulmonary Emphysema". Annals of Internal Medicine 58 (6): 953–960. PMID 14024192. http://www.annals.org/content/58/6/953.extract. 
7. ^ Pasquale Ciaglia, Rita Firsching, and Cynthia Syniec (Jun 1985). "Elective percutaneous dilatational tracheostomy. A new simple bedside procedure; preliminary report". Chest: 715–9. doi:10.1378/chest.87.6.715. PMID 3996056. 
8. ^ William M. Griggs, Lindsay I. Worthley, John E. Gilligan, Peter D. Thomas, and John A. Myburgh (Jun 1990). "A simple percutaneous tracheostomy technique". Surgery Gynecology and Obstetrics: 543–5. 
9. ^ ^{a b} Sushil P. Ambesh, Chandra K. Pandey, Shashi Srivastava, Anil Agarwal and Dinesh K. Singh (December 2002). "Percutaneous Tracheostomy with Single Dilatation Technique: A Prospective, Randomized Comparison of Ciaglia Blue Rhino Versus Griggs’ Guidewire Dilating Forceps". Anesthesia & Analgesia 95 (6): 1739–1745. doi:10.1097/00000539-200212000-00050. PMID 12456450. http://www.anesthesia-analgesia.org/content/95/6/1739.long. 
10. ^ Añón, José M; Gómez, Vicente; Escuela, Maria Paz et al. (2000). "Percutaneous tracheostomy: comparison of Ciaglia and Griggs techniques". Critical Care 4 (2): 124–8. doi:10.1186/cc667. PMC 29040. PMID 11056749. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=29040. 
11. ^ Van Heurn, LW; van Geffen, GJ; Brink, PR (1996). "Clinical experience with percutaneous dilatational tracheostomy: report of 150 cases". European Journal Surgery 162 (7): 531–5. PMID 8874159. 
12. ^ Polderman, KH; Spijkstra, Jan Jaap; de Bree, Remco et al. (2003). "Percutaneous dilatational tracheostomy in the ICU: optimal organization, low complication rates, and description of a new complication". Chest 123 (5): 1595–602. doi:10.1378/chest.123.5.1595. PMID 12740279. 
13. ^ Hill, Bradley B; Zweng, TN; Maley, RH et al. (1996). "Percutaneous dilational tracheostomy: report of 356 cases". Journal of Trauma 41 (2): 238–43. doi:10.1097/00005373-199608000-00007. PMID 8760530. 
14. ^ Powell, DM; Price, PD; Forrest, LA (1998). "Review of percutaneous tracheostomy". The Laryngoscope 108 (2): 170–7. doi:10.1097/00005537-199802000-00004. PMID 9473064. 
15. ^ Karin S. Hotchiss, Judith C. McCaffrey (January 2003). "Laryngotracheal injury after percutaneous dilational tracheostomy in cadaver specimens". Laryngoscope 113 (1): 16–20. doi:10.1097/00005537-200301000-00003. 
16. ^ C. Byhahn, V. Lischke, S. Halbig, G. Scheifler, K. Westphal (December 2002). "[Ciaglia blue rhino: a modified technique for percutaneous dilatation tracheostomy. Technique and early clinical results] Article in German". Anaesthesist 49 (3): 202–206. PMID 10788989. 
17. ^ ^{a b c} Steven E. Sittig and James E. Pringnitz (February 2001). "Tracheostomy: evolution of an airway". AARC Times: 48–51. http://www.tracheostomy.com/resources/pdf/evolution.pdf. 
18. ^ ^{a b c d e} O. Rajesh & R. Meher (2006). "Historical Review Of Tracheostomy". The Internet Journal of Otorhinolaryngology 4 (2). ISSN 1528-8420. http://www.ispub.com/journal/the_internet_journal_of_otorhinolaryngology/volume_4_number_2_33/article/historical_review_of_tracheostomy.html. 
19. ^ Patricia Skinner (2008). "Unani-tibbi". In Laurie J. Fundukian. The Gale Encyclopedia of Alternative Medicine (3rd ed.). Farmington Hills, Michigan: Gale Cengage. ISBN 9781414448725. http://findarticles.com/p/articles/mi_g2603/is_0007/ai_2603000716/. 
20. ^ Mostafa Shehata (April 2003). "The Ear, Nose and Throat in Islamic Medicine". Journal of the International Society for the History of Islamic Medicine 2 (3): 2–5. ISSN 1303-667x. http://www.ishim.net/ishimj/3/01.pdf. 
21. ^ ^{a b} Goodall, E.W. (1934). "The story of tracheostomy". British Journal of Children's Diseases 31: 167–76, 253–72. 
22. ^ Armytage WHG (1960). "Giambattista Della Porta and the segreti". British Medical Journal 1 (5179): 1129–1130. doi:10.1136/bmj.1.5179.1129. PMC 1966956. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1966956. 
23. ^ ^{a b} Nicholas Habicot (1620) (in French). Question chirurgicale par laquelle il est démonstré que le Chirurgien doit assurément practiquer l'operation de la Bronchotomie, vulgairement dicte Laryngotomie, ou perforation de la fluste ou du polmon. Paris: Corrozet. pp. 108. 
24. ^ Sanctorii Sanctorii (1646) (in Latin). Sanctorii Sanctorii Commentaria in primum fen, primi libri canonis Avicennæ. Venetiis: Apud Marcum Antonium Brogiollum. pp. 1120. OCLC OL15197097M. http://openlibrary.org/works/OL5226737W/Sanctorii_Sanctorii_Commentaria_in_primum_fen_primi_libri_canonis_Auicennæ_... 
25. ^ Julius Casserius (Giulio Casserio) and Daniel Bucretius (1632) (in Latin). Tabulae anatomicae LXXIIX … Daniel Bucretius … XX. que deerant supplevit & omnium explicationes addidit. Francofurti: Impensis & coelo Matthaei Meriani. http://www.antiqbook.com/boox/gac/089233.shtml. 
26. ^ Cawthorne T, Hewlett AB, Ranger D (1959). "Tracheostomy in a Respiratory Unit at a Neurological Hospital". Procedings of the Royal Society of Medicine 52 (6): 403–405. PMC 1871130. PMID 13667911. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1871130. 
27. ^ Georges Detharding (1745). "De methodo subveniendi submersis per laryngotomiam (1714)". In Von Ernst Ludwig Rathlef, Gabriel Wilhelm Goetten, Johann Christoph Strodtmann. Geschichte jetzlebender Gelehrten, als eine Fortsetzung des Jetzlebenden. Zelle: Berlegts Joachim Undreas Deek. pp. 20. http://books.google.de/books?id=flM5AAAAMAAJ&pg=PA6#v=onepage&q&f=false. 
28. ^ Price JL (1962). "THE EVOLUTION OF BREATHING MACHINES". Medical History 6 (1): 67–72. PMC 1034674. PMID 14488739. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1034674. 
29. ^ Wischhusen HG; Schumacher, GH (1977). "Curriculum vitae of the professor of anatomy, botany and higher mathematics Georg Detharding (1671-1747) at the University of Rostock" (in German). Anat Anz 142 (1-2): 133–140. PMID 339777. http://www.ncbi.nlm.nih.gov/pubmed/339777. 
30. ^ Armand Trousseau (1833). "Mémoire sur un cas de tracheotomie pratiquée dans la période extrème de croup". Journal des connaissances médico-chirurgicales 1 (5): 41. 
31. ^ Armand Trousseau (1852). "Nouvelles recherches sur la trachéotomie pratiquée dans la période extrême du croup". In Jean Lequime and J. de Biefve. Annales de médecine belge et étrangère. Brussels: Imprimerie et Librairie Société Encyclographiques des Sciences Médicales. pp. 279–288. http://books.google.com/?id=khsUAAAAQAAJ&pg=PA279&lpg=PA279&dq=%22Nouvelles+recherches+sur+la+trach%C3%A9otomie+pratiqu%C3%A9e+dans+la+p%C3%A9riode+extr%C3%AAme+du+croup%22&q=%22Nouvelles%20recherches%20sur%20la%20trach%C3%A9otomie%20pratiqu%C3%A9e%20dans%20la%20p%C3%A9riode%20extr%C3%AAme%20du%20croup%22. 
32. ^ Snow, J (1858). "Fatal cases of inhalation of chloroform, Treatment of suspended animation from chloroform". In Richardson, BW. On chloroform and other anaesthetics:their action and administration. London: John Churchill. pp. 120–200, 251–62. http://books.google.com/books?id=yOI8AAAAcAAJ&printsec=frontcover&dq=john+snow&hl=en&ei=pjacTe6zJMal8QOv0IHfBg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDkQ6AEwAQ#v=onepage&q&f=false. 
33. ^ Trendelenburg, F (1871). "Beiträge zu den Operationen an den Luftwegen [Contributions to airways surgery]" (in German). Archiv für Klinische Chirurgie 12: 112–33. 
34. ^ Macewen, W (1880). "General observations on the introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy". British Medical Journal 2 (1021): 122–4. doi:10.1136/bmj.2.1021.122. PMC 2241154. PMID 20749630. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2241154. 
35. ^ Macewen, W (1880). "Clinical observations on the introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy". British Medical Journal 2 (1022): 163–5. doi:10.1136/bmj.2.1022.163. PMC 2241109. PMID 20749636. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2241109. 

External links

• Tracheotomy Info (A Community For Tracheotomy-wearers and the people who love them) at tracheotomy.info
• Aaron's tracheostomy page (Caring for a tracheostomy) at tracheostomy.com
• How to perform an emergency tracheotomy (This page actually depicts cricothyroidotomy, not tracheostomy)
• RT Corner (Educational Site for RT's and Nurses) at rtcorner.net
• (Pictures with video clipping) at drtbalu.com
• "Tracheotomy" at Dorland's Medical Dictionary

• Smiths Medical Tracheostomy Training Videos