Introduction
Complications in airway management causing temporary harm to individuals are common, but severe injury is rare. Most complications occur in accessible airways. These complications may sometimes prove fatal. However, such complications are rare. A noticeable amount of airway complications occur in ICUs (intensive care units) and emergency departments. Hypoxia (unavailability of oxygen to the tissues) is one of the common causes of death due to complications in airway management. Obesity increases the risk of airway complications. Pulmonary aspiration is a common cause of airway-related anesthetic deaths. Avoiding airway complications requires careful assessment, preparedness, good planning, judgment, teamwork, knowledge, various techniques and devices, and a willingness to stop performing them when they fail. Major airway complications occur in areas where the practice could be better. Research is needed to improve understanding, prevention, and management of such complications.
What Leads To Inadequate Ventilation?
Respiratory Effort - Insufficient respiratory attempt resulting from internal (intracranial hemorrhage) or external (opioid overdose) factors. Poor respiratory ventilation can be challenging to recognize as it is often silent, and detection depends on close observation of chest wall movement. The patient should be undressed and observed for the rate, pattern, and depth of breathing, use of accessory muscles, abnormal sounds, and signs of injury.
Airway Obstruction - Soft tissue airway obstruction can occur by several mechanisms. These mechanisms include the tongue falling back into the posterior part of the pharynx (the hollow tube starting at the back of the nose and ending at the top of the windpipe) and loss of muscular contraction in the soft palate area. Simple airway techniques, such as the jaw thrust with or without a head tilt, or head-tilt chin-lift, can help fix this problem quickly. Obstruction can also occur by foreign bodies, injured tissue, blood, and secretions.
Various sounds produced by the obstructed upper airway often make such obstruction easier to detect than poor respiratory effort. For example, sounds like snoring or gurgling noises can be heard when the upper airway becomes partially obstructed by soft tissue or liquid, such as blood or vomitus. Complete airway obstruction is silent but may intermittently become evident due to the retractions of the accessory muscles of respiration (suprasternal, supraclavicular, intercostal, subcostal) or bluish discoloration of the skin until a complete respiratory arrest occurs.
Why Is Establishing an Adequate Airway Important?
Establishing an adequate airway is of utmost importance in managing individuals in the operation theatre and the emergency department. Endotracheal intubation is a safe maneuver that is performed daily by healthcare personnel. However, endotracheal intubation is not risk-free and has its share of complications. Such complications might range from minor soft tissue injuries to severe, long-term, life-threatening airway complications.
Endotracheal intubation-led airway injury ranges from 0.5 to 7 percent. Such injuries can occur at the beginning of intubation or can result from prolonged intubation. It has been found that the larynx or the voice box is the most common site of injury, followed by the pharynx and the esophagus (food pipe). Intubation-related injury is also a financial burden. The length of hospital stay, repeated admissions, and hospital cost for individuals with intubation-related injuries is more than that for other individuals without intubation injuries.
Some complications or injuries, such as soft tissue hematomas, lacerations, and arytenoid dislocation, result from the initial intubation process. Other injuries might result from tissue-endotracheal tube (ETT) interactions, such as laryngotracheal stenosis and vocal fold paralysis, even if intubation was performed without direct tissue trauma.
What Are the Initial Complications of Intubation?
Nasal Cavity:
Nasotracheal intubation is carried out in individuals who require surgical access to the oral cavity, such as in otolaryngology, head-and-neck, or maxillofacial surgery cases. It is also a preferred intubation method of intubation in individuals with trismus. Epistaxis or bleeding from the nose might result from soft tissue injury, such as injury to the mucosa. The epistaxis is self-limiting and is the most common minor mild tissue injury to the nasal mucosa. Blood pooling in the oral cavity is considered a severe complication. If the blood remains trapped within the mucosal surfaces of the nose, hematomas may result, leading to structural deformity.
Oral Cavity:
During laryngoscopy, injury to the oral cavity and teeth is a common complication. Dental injuries often occur due to pressure on the upper front teeth, which are used as a fulcrum for the laryngoscope while visualizing the larynx. Laryngoscopy may also cause soft tissue injury to the lips, oral mucosa, floor of mouth, palate, and tongue. The insertion of endotracheal tubes, orogastric tubes, temperature probes, and oral airways can also cause these injuries. Oral cavity injury leads to discoloration of the mucosa, hematoma formation, blood-laden secretions, or blood oozing from scraped surfaces during suctioning.
Larynx:
The laryngeal injury occurs in most cases of endotracheal intubation. Laryngeal injuries include ulcers, vocal cord erythema, granulomas, and, less commonly, vocal cord immobility. Many individuals complain of vocal fatigue, dysphagia, sore throat, hoarseness, throat clearing, and aspiration. These injuries take longer to heal and could lead to prolonged voice problems and hoarseness.
What Are the Late Complications of Intubation?
Laryngotracheal Stenosis:
Laryngotracheal stenosis is one of the long-term consequences of intubation. Endotracheal intubationis a common cause of laryngotracheal stenosis. The duration of intubation is directly proportional to the occurrence of laryngeal pathologies, such as subglottic edema and narrowing, when intubation time exceeds seven days. Comorbidities, such as diabetes mellitus, gastroesophageal reflux, and immunosuppression, can make individuals prone to develop stenosis.
Tracheal Changes:
Cuffed endotracheal or tracheotomy tubes cause acquired tracheomalacia. Tracheomalacia occurs as a result of pressure due to necrosis secondary to the increased cuff pressures, movement of the tube, chronic inflammation, and infection leading to thinning and destruction of the tracheal cartilages. Loss of the tracheal cartilage causes weakening of the tracheal wall, leading to collapse and airway obstruction while breathing. Clinically it can lead to mild dyspnea (shortness of breath), chronic cough, and wheezing to complications, such as stridor (abnormal high-pitched music sound), airway compromise, and eventually respiratory failure. Tracheotomy and intubation may also lead to tracheoinnominate artery fistula due to pressure necrosis of the tip of the tube or cuff with the erosion of the anterior tracheal wall.
Injuries Due to Video Laryngoscopy:
The most common complication of video laryngoscope includes injury to the soft palate, teeth, larynx, tongue, and retromolar region. The video laryngoscope causes the tonsils to stretch, making them more prone to injury with tube advancement. Soft tissue damage in normal laryngoscopy is caused mainly due to the insertion of the laryngoscope, but soft tissue injury with the video laryngoscope is caused by the insertion of the endotracheal tube itself, as it is blindly inserted into the oral cavity and pharynx.
Conclusion
Endotracheal intubation is a safe and life-saving procedure. Acute or chronic injuries can occur at the time of endotracheal intubation. Difficult intubations can lead to airway injury. The skill of the personnel carrying out the intubation is also one of the factors causing complications in airway management. Soft tissue injury may occur in the nasal and oral cavities, oropharynx, and larynx. These injuries are caused mainly due to incorrect insertion of the endotracheal tubes. Most of them heal on their own without causing severe symptoms.
