Intubation granuloma | |
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Laryngoscopic view of the vocal process. An intubation granuloma is visible as a pale nodule on the left posterior laryngeal wall. |
Intubation granuloma is a benign growth of granulation tissue in the larynx or trachea, which arises from tissue trauma due to endotracheal intubation. [1] This medical condition is described as a common late complication of tracheal intubation, specifically caused by irritation to the mucosal tissue of the airway during insertion or removal of the patient's intubation tube. [1] [2]
Endotracheal intubation is a common medical procedure, performed to assist patient ventilation and protect the airway. [2] [3] However, prolonged endotracheal intubation, the use of inappropriate intubation equipment, or improper airway manipulation by the medical team may directly lead to mechanical trauma, resulting in laryngeal granuloma formation in the subglottis of the larynx. [4] Diagnosis of intubation granulomas are achieved through identifying proliferating tissues in the vocal folds via laryngoscopy. [2]
Primary treatment for intubation granulomas tends to involve surgical excision of the granuloma. However, single treatment methods alone often result in high incidences of recurrence, hence combined therapy is suggested. [5] Secondary methods involve low dose radiotherapy and corticosteroid drug treatments. [6] For extreme cases of refractory granulomas, in which the aforementioned treatment methods all prove ineffective, botulinum toxin injections and oral zinc sulfate treatments are administered. [7] [8]
Other significant risk factors are associated with intubation granuloma formation as well, such as a patient's age, sex, intubation history and pre-existing medical conditions, which indirectly predispose certain patients to intubation-related injuries. [1] [9]
Persistent sore throat, hoarseness, and vocal fatigue following intubation procedures are common symptoms of intubation granuloma, and patients may report mild discomfort associated with the sensation of a rough foreign body lodged in the back of the throat. [1] [2] [9] These symptoms often provoke observable clinical signs such as frequent coughing, throat-clearing, and hoarseness accompanied by dysphonia, reduced voice quality and restricted vocal range. [2] [10] Severe intubation granulomas cause pharyngitis and pain upon pressed phonation, coughing or throat clearing. [11] In some cases, the patient may even experience dyspnea, or shortness of breath due to airway obstruction by the granuloma. [12] [13]
However, since granulomas and other vocal cord polyps may take weeks or months to develop, intubation granulomas may sometimes be clinically evident only when the aforementioned symptoms persist for, or reappear after a longer period of time post-extubation. [14] Initial symptoms may also be overlooked as they coincide with typical side-effects of intubation. [15] Case reports of patients diagnosed and treated for intubation granulomas concur with this observation, as the diagnosis is often made weeks or months after the patient is extubated. [1] [16]
Tracheal and laryngeal trauma leading to an intubation granuloma are caused by traumas during the intubation processes, directly resulting from technical circumstances such as specifications of the breathing tube equipment, method of insertion, and intubation duration. [4] [9]
Intubation duration
Statistically, patients intubated for more than 48 hours will experience some form of laryngeal injury attributed to intubation, and approximately half of the injuries will result in the development of granulation tissue in the vocal fold. [17] While there is no consensus on the maximal permissible duration of safe endotracheal intubation, the risk of trauma-related laryngeal granuloma formation increases significantly with prolonged durations of tracheal intubation. [4] [18] However, there are also studies which have not found statistically significant correlations between prolonged intubation duration with the degree of laryngeal injury, and intubation granuloma cases have also been reported in patients who have been intubated for only a few hours. [1] [17]
Intubation tube diameter
Appropriate intubation tube sizes are defined as those small enough to minimise risks of mucosal trauma while large enough to maintain adequate ventilation. [4] This is especially important in the field of pediatrics, where the development of a child's trachea may vary according to age. [19] Age-based calculations of appropriately sized intubation tubes are conducted in accordance with the Khine formula, which are based on internal diameters. [20] Unfortunately, these formulas do not account for variances in outer diameter and cuff dimensions, which may result in varying tube sizes. [21] Alternatively, height-based calculations are also available. [22] According to PALS (2010) guidelines, the use of length-based resuscitation tapes has proven to be more accurate than age-based estimates of endotracheal intubation tubes. [4]
Cuff pressure
The addition of an endotracheal tube cuff decreases the likelihood of selecting oversized breathing tubes for the patient, while also preventing microaspiration and the leakage of respiratory gases during intubation. [23] However, hyperinflation of the cuff places excessive pressure on the tracheal wall, causing trauma or ischaemia to nearby tissue and hence increasing the risk of granuloma formation. [24] Cuff pressures can be monitored during endotracheal intubation via manometers to prevent nitrous oxide induced hyperinflation. [25] [26] General guidelines suggest that cuff pressure should be maintained between 20 and 30 cm to minimise risks of intubation-related trauma. [2] [27]
Intubation granulomas are most commonly presented in the form of red or pale spherical lesions in the subglottis of the larynx and may be defined as protruding, inflamed fibrovascular tissue. [10] [17] While it is possible for intubation granulomas to form in both the larynx or trachea, they are most characteristically located in the posterior third aspect of the larynx, stemming from the posterior vocal fold directly above the vocal process cartilage. [28] Diagnosis of granulomas are confirmed via videolaryngostroboscopy and the electromyography by identifying proliferating tissue originating in the vocal process. [2] Furthermore, granuloma severity can be determined using screening images of laryngoscopy and graded in accordance to Farwell's grading system. [29]
When a patient lies supine, the ventilation tube tends to rest on the posterior part of the larynx, above three major potential sites of damage: the arytenoid cartilage, posterior glottis, and cricoid cartilage. [30] Excessive pressure or friction from contact between the tube and the mucosal cell layer of the larynx, which may occur at rest or by unexpected myoclonic movement under sedation (such as coughing or swallowing), can lead to mucosal injury. [30] Under high capillary perfusion pressure, the mucosal cells of the larynx experience pressure ischemia, leading to tissue irritation, acute inflammation, congestion and edema. [30] Ischemic necrosis may occur, leading to erosion and ulcer formation in mucous membranes before progressing to the perichondrium and cartilage. [30] In other cases where granulomas are found in areas not on the posterior larynx, such tissue injury can also be accounted for by accidental lacerations from the tip of the endotracheal tube or its introducer. [30]
During prolonged intubation, constant stress on the laryngeal tissue prevents full wound recovery until the endotracheal tube is removed. [30] Although the formation of granulation tissue is part of a typical wound healing process, incomplete healing of the mucosal layer and persistent perichondritis causes the formation of chronic, rounded, localized granulation tissue over the ulceration site. [30] As the granulation tissue matures, other cells such as macrophages, fibroblasts and keratinocytes migrate to the granulation tissue to aid the healing process, causing fibrosis of the growth and the production of a protective epithelial layer. [31] Ultimately, a pedunculated globular mass consisting of immune cells, fibroblasts, myofibroblasts, keratinocytes and endothelial cells is formed. [31]
In some cases, the granuloma has been reported to regress after extubation without any medical intervention. [2] However, if the granuloma is not removed and continues to proliferate, this may pose further health risks to the patient, such as airway obstruction or stenosis. [2] In future intubations, even more caution would be required to perform the procedure while avoiding disruption of the granuloma. [13]
The main treatment of intubation-related laryngeal granulomas is microlaryngeal surgical excision, but low dose radiotherapy and other drugs such as corticosteroids, botulinum toxin and zinc sulfate are also used in support to treat related symptoms or manage granuloma recurrence. [5] [6]
Surgical excision
The main treatment of intubation-related laryngeal granulomas is microlaryngeal surgical excision of the granuloma under anesthesia. [28] [6] Excision surgeries can be performed by cold steel excision or laser ablations - Laser surgeries permit more accurate excisions and hence reduce risks of damaging surrounding tissues. [32] This method can be further accompanied by jet ventilation, which minimises intubation trauma and reduces risks of edema and barotrauma by providing ventilation over stenosis. [28] A thin cannula and catheter can be further used in place of traditional small-diameter endotracheal tubes during surgery, which enables precise visualisation of anatomical configurations within the surgical field. [28] Employing infraglottic transtracheal routes for microlaryngeal surgery is more effective than supraglottic methods as it provides ventilation under vocal cords, which causes minimal vocal cord movement. [33]
However, excision surgeries alone usually result in high incidences of granuloma recurrence. [5] Consequently, surgical approaches are usually accompanied by low dose radiotherapy, corticosteroids and botulinum toxin treatment. [7] [8] [34] [35]
Low dose radiotherapy
Low dose radiotherapy ranging between 800 and 3000 cGy (centigray) has been documented to have a high successful prevention and resolution of laryngeal granulomas. [35] The optimal period for radiotherapy treatment is immediately after surgical excision, preferably prior to injury-stimulated tissue proliferation. [36]
Corticosteroids
Corticosteroid drug treatments can be administered orally and through inhalation. Inhaled steroids have the greatest efficacy in resolving reducing local inflammation of the granuloma. [11] [34] [37] The most commonly prescribed inhaled steroid, budesonide, can resolve intubation granulomas within 12 months of treatment. [34]
However, due to the side effects of steroidal interventions, antibiotics have to be prescribed alongside to reduce pain and inflammation in the region of the target granuloma. [37]
Botulinum toxin and Zinc sulfate
Botulinum toxin (BOTOX) and Zinc sulfate treatments are mainly applied to cases of refractory granulomas, which are immune to previously mentioned treatment methods. [7] [8]
Intralaryngeal BOTOX injections bind specifically and non-competitively to presynaptic cholinergic neuron membranes at neuromuscular junctions which induce zinc-dependent cleavage of proteins involved in neuroexocytosis. [38] The breakdown of neuroexocytosis proteins block acetylcholine secretions which inhibit hypertonicity, strengthen antagonist muscles and restore the balance of forces. [38] Since laryngeal granuloma formations are exacerbated by repeated forceful contraction of the glottis, the combined effects of the toxin induce thyroarytenoid paresis and decreases the force of vocal fold adduction which inhibit forced contact between vocal processes, hence facilitating granuloma resolution. [39] [40]
Oral zinc sulfate treatments are advantageous due to their ability to preserve the anatomical and functional integrity of the vocal cords. [8] Similarly, this form of therapy can achieve quick relief of granuloma-related symptoms whilst avoiding invasive surgery and toxic drug effects. [8]
Intubation granuloma onset has been found to be more prevalent in certain demographics due to their associated anatomical characteristics. [9] The physiological differences due to age, gender, or inherited features may place such patients at an increased risk of intubation injury, and subsequently the occurrence of intubation granulomas. [4] [9]
Age
Pediatric and geriatric patients are at higher risk of laryngeal injury. [4] Compared to adults, newborns and young children possess a higher, more anterior larynx, a larger and stiffer epiglottis as well as a more fragile laryngotracheal mucosa, making them more vulnerable to traumatic damage by prolonged tracheal intubation. [4] [9] In addition, the fragility of the mucous larynx increases with age, leaving the patient more prone to intubation-induced tracheal and laryngeal injuries. [2] [41]
Gender
Females were found to be at greater risk of intubation granulomas as they tend to have a narrower glottis, lower glottic proportion and a thinner arytenoid mucochondrium. [1] [9] 75% to 90% of intubation granulomas found in the vocal cords are reported in female patients. [1] [34] Furthermore, females displayed greater postintubation pharyngitis, which have led to increased incidence of intubation granulomas. [42]
Anatomical characteristics
Congenital and/or acquired abnormalities of the larynx - laryngeal webs, bands, cysts and tumours - are predisposing risk factors of intubation granuloma. [9] In addition, facial and cervical anomalies, short necks, receding chins and obesity can heighten the difficulty in successful laryngoscopy, predisposing the patient to traumatic intubation as their airway becomes more challenging to navigate during the intubation process. [1] [9]
Tracheal intubation, usually simply referred to as intubation, is the placement of a flexible plastic tube into the trachea (windpipe) to maintain an open airway or to serve as a conduit through which to administer certain drugs. It is frequently performed in 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.
Tracheotomy, or tracheostomy, is a surgical airway management procedure which consists of making an incision (cut) on the anterior aspect (front) of the neck and opening a direct airway through an incision in the trachea (windpipe). The resulting stoma (hole) can serve independently as an airway or as a site for a tracheal tube or tracheostomy tube to be inserted; this tube allows a person to breathe without the use of the nose or mouth.
Laryngoscopy is endoscopy of the larynx, a part of the throat. It is a medical procedure that is used to obtain a view, for example, of the vocal folds and the glottis. Laryngoscopy may be performed to facilitate tracheal intubation during general anaesthesia or cardiopulmonary resuscitation or for surgical procedures on the larynx or other parts of the upper tracheobronchial tree.
Laryngitis is inflammation of the larynx. Symptoms often include a hoarse voice and may include fever, cough, pain in the front of the neck, and trouble swallowing. Typically, these last under two weeks.
A tracheal tube is a catheter that is inserted into the trachea for the primary purpose of establishing and maintaining a patent airway and to ensure the adequate exchange of oxygen and carbon dioxide.
A laryngeal mask airway (LMA), also known as laryngeal mask, is a medical device that keeps a patient's airway open during anaesthesia or while they are unconscious. It is a type of supraglottic airway device. They are most commonly used by anaesthetists to channel oxygen or inhalational anaesthetic to the lungs during surgery and in the pre-hospital setting for unconscious patients.
Airway management includes a set of maneuvers and medical procedures performed to prevent and relieve airway obstruction. This ensures an open pathway for gas exchange between a patient's lungs and the atmosphere. This is accomplished by either clearing a previously obstructed airway; or by preventing airway obstruction in cases such as anaphylaxis, the obtunded patient, or medical sedation. Airway obstruction can be caused by the tongue, foreign objects, the tissues of the airway itself, and bodily fluids such as blood and gastric contents (aspiration).
Respiratory arrest is a serious medical condition caused by apnea or respiratory dysfunction severe enough that it will not sustain the body. Prolonged apnea refers to a patient who has stopped breathing for a long period of time. If the heart muscle contraction is intact, the condition is known as respiratory arrest. An abrupt stop of pulmonary gas exchange lasting for more than five minutes may permanently damage vital organs, especially the brain. Lack of oxygen to the brain causes loss of consciousness. Brain injury is likely if respiratory arrest goes untreated for more than three minutes, and death is almost certain if more than five minutes.
Laryngectomy is the removal of the larynx. In a total laryngectomy, the entire larynx is removed with the separation of the airway from the mouth, nose and esophagus. In a partial laryngectomy, only a portion of the larynx is removed. Following the procedure, the person breathes through an opening in the neck known as a stoma. This procedure is usually performed by an ENT surgeon in cases of laryngeal cancer. Many cases of laryngeal cancer are treated with more conservative methods. A laryngectomy is performed when these treatments fail to conserve the larynx or when the cancer has progressed such that normal functioning would be prevented. Laryngectomies are also performed on individuals with other types of head and neck cancer. Less invasive partial laryngectomies, including tracheal shaves and feminization laryngoplasty may also be performed on transgender women and other female or non-binary identified individuals to feminize the larynx and/or voice. Post-laryngectomy rehabilitation includes voice restoration, oral feeding and more recently, smell and taste rehabilitation. An individual's quality of life can be affected post-surgery.
In anaesthesia and advanced airway management, rapid sequence induction (RSI) – also referred to as rapid sequence intubation or as rapid sequence induction and intubation (RSII) or as crash induction – is a special process for endotracheal intubation that is used where the patient is at a high risk of pulmonary aspiration. It differs from other techniques for inducing general anesthesia in that several extra precautions are taken to minimize the time between giving the induction drugs and securing the tube, during which period the patient's airway is essentially unprotected.
Stridor is an extra-thoracic high-pitched breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree. It is different from a stertor, which is a noise originating in the pharynx.
Contact granuloma is a condition that develops due to persistent tissue irritation in the posterior larynx. Benign granulomas, not to be confused with other types of granulomas, occur on the vocal process of the vocal folds, where the vocal ligament attaches. Signs and symptoms may include hoarseness of the voice, or a sensation of having a lump in the throat, but contact granulomas may also be without symptoms. There are two common causes associated with contact granulomas; the first common cause is sustained periods of increased pressure on the vocal folds, and is commonly seen in people who use their voice excessively, such as singers. Treatment typically includes voice therapy and changes to lifestyle factors. The second common cause of granulomas is gastroesophageal reflux and is controlled primarily through the use of anti-reflux medication. Other associated causes are discussed below.
The Combitube—also known as the esophageal tracheal airway or esophageal tracheal double-lumen airway—is a blind insertion airway device (BIAD) used in the pre-hospital and emergency setting. It is designed to provide an airway to facilitate the mechanical ventilation of a patient in respiratory distress.
Subglottic stenosis is a congenital or acquired narrowing of the subglottic airway. It can be congenital, acquired, iatrogenic, or very rarely, idiopathic. It is defined as the narrowing of the portion of the airway that lies between the vocal cords and the lower part of the cricoid cartilage. In a normal infant, the subglottic airway is 4.5-5.5 millimeters wide, while in a premature infant, the normal width is 3.5 millimeters. Subglottic stenosis is defined as a diameter of under 4 millimeters in an infant. Acquired cases are more common than congenital cases due to prolonged intubation being introduced in the 1960s. It is most frequently caused by certain medical procedures or external trauma, although infections and systemic diseases can also cause it.
Tracheobronchial injury is damage to the tracheobronchial tree. It can result from blunt or penetrating trauma to the neck or chest, inhalation of harmful fumes or smoke, or aspiration of liquids or objects.
Tracheal intubation, an invasive medical procedure, is the placement of a flexible plastic catheter into the trachea. For millennia, tracheotomy was considered the most reliable method of tracheal intubation. By the late 19th century, advances in the sciences of anatomy and physiology, as well as the beginnings of an appreciation of the germ theory of disease, had reduced the morbidity and mortality of this operation to a more acceptable rate. Also in the late 19th century, advances in endoscopic instrumentation had improved to such a degree that direct laryngoscopy had finally become a viable means to secure the airway by the non-surgical orotracheal route. Nasotracheal intubation was not widely practiced until the early 20th century. The 20th century saw the transformation of the practices of tracheotomy, endoscopy and non-surgical tracheal intubation from rarely employed procedures to essential components of the practices of anesthesia, critical care medicine, emergency medicine, gastroenterology, pulmonology and surgery.
The laryngeal tube is an airway management device designed as an alternative to other airway management techniques such as mask ventilation, laryngeal mask airway, and tracheal intubation. This device can be inserted blindly through the oropharynx into the hypopharynx to create an airway during anaesthesia and cardiopulmonary resuscitation so as to enable mechanical ventilation of the lungs.
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.
Endoscopic laser cordectomy, also known as Kashima operation, is an endoscopic laser surgical procedure performed for treating the respiratory difficulty caused as a result of bilateral abductor vocal fold paralysis. Bilateral vocal fold paralysis is basically a result of abnormal nerve input to the laryngeal muscles, resulting in weak or total loss of movement of the laryngeal muscles. Most commonly associated nerve is the vagus nerve or in some cases its distal branch, the recurrent laryngeal nerve. Paralysis of the vocal fold may also result from mechanical breakdown of the cricoarytenoid joint. It was first described in by Kashima in 1989.
Tracheoinnominate fistula is an abnormal connection (fistula) between the innominate artery and the trachea. A TIF is a rare but life-threatening iatrogenic injury, usually the sequela of a tracheotomy.
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