Endotracheal Intubation

Laryngeal granuloma is an uncommon complication arising from irritation of the laryngeal structures. We present a case where bilateral laryngeal granulomas became clinically evident 3 mo after orthognathic surgery. The patient, a 19yr-old female, developed acute dyspnea after experiencing gradual voice loss. Excision of the lesions under endotracheal general anesthesia led to an uneventful outcome. The causes, predisposing factors, diagnostic features, and treatment of laryngeal granuloma are reviewed.

Laryngeal granuloma is an uncommon complication arising from irritation of the laryngeal structures. We present a case where bilateral laryngeal granulomas became clinically evident 3 mo after orthognathic surgery. The patient, a 19yr-old female, developed acute dyspnea after experiencing gradual voice loss. Excision of the lesions under endotracheal general anesthesia led to an uneventful outcome. The causes, predisposing factors, diagnostic features, and treatment of laryngeal granuloma are reviewed. he use of endotracheal intubation in the administration of general anesthesia during oral and maxillofacial surgery, although commonplace, is associated with potential complications. In maxillofacial procedures that require prolonged intubation and involve considerable movement of the head and neck, patients are at an increased risk of certain postanesthetic sequelae.1 One complication that can result from prolonged endotracheal intubation is the postoperative development of laryngeal granuloma. This infrequent entity is postulated to occur as a result of abrasion of the vocal cords, often due to traumatic intubation, or pressure necrosis.23 This case report describes a patient who developed this problem following orthognathic surgery.

CASE REPORT
A 19-yr-old female from Guyana was admitted in February of 1989 to Kings County Hospital Center for the surgical correction of a dentofacial deformity. The patient denied any previous surgical or medical history prior to this hospitalization.
The patient was taken to the operating room and placed in the supine position. Premedication consisted of 100 /.g fentanyl (Sublimaze) and 0.2 mg glycopyrrolate (Robinul) infused intravenously and 0.25% phenylephrine (Neo-Synephrine) drops into both nares. Following a test dose of 50 mg thiopental (Pentothal), a bolus of 225 mg was administered as well as 8 mg vecuronium (Norcuron) to facilitate intubation. The patient was nasally intubated utilizing a soft 7.0 endotracheal tube (Porex Co., Keene, NH), and the cuff was inflated with a volume of air felt to occlude any leak around the cuff. The intubation was performed atraumatically on the first attempt. In addition, an esophageal stethoscope with temperature probe was placed in the other naris, and its position within the esophagus was verified. General anesthesia was maintained with fentanyl and isoflurane/nitrous oxide/oxygen, together with vecuronium for muscle relaxation. The duration of anesthesia was 6 hr and 45 min. Cuff pressure was adjusted "by feel" intraoperatively. The patient remained intubated during the postoperative period when surgical edema and maxillomandibular fixation of the obtunded patient mandated the maintenance of a secure airway. The total duration of intubation was 18 hr. The patient was weaned from controlled ventilation to spontaneous respiration, and extubation was performed uneventfully. The patient's postoperative course was without incident, and she was discharged on postoperative day 3.
The patient was seen in the outpatient clinic for postoperative evaluation during her period of maxillomandibular fixation and thereafter for further orthodontic treatment.
Almost exactly 3 mo following corrective orthognathic surgery, the patient experienced an acute onset of dyspnea with associated tightness in her chest. The patient's complaints prior to presentation to the emergency room for respiratory distress included hoarseness and gradual voice loss, which began 2 wk before this hospitalization. Stridor was evident during auscultation, and she was taken quickly to the operating room for direct laryngoscopy, excision of possible vocal cord ISSN 0003-3006/91/$5.00 polyps, and possible tracheostomy. Anesthetic management initially included intravenous sedation with direct laryngoscopy to visualize the granulomas. The sedated patient was intubated with a small tube using a fiberoptic laryngoscope.
Intraoperatively, two large vocal cord granulomas were noted obstructing her airway. The granulomas were bilateral and pedunculated, arising from the vocal processes of the arytenoid cartilages. Following excision, the patient had an improving hospital course and was discharged 2 days after surgery. The patient was followed as an outpatient for several months, and no recurrence was noted.

DISCUSSION
Laryngeal granuloma is a well-documented entity and can be quite upsetting when a patient presents with the often sudden and potentially life-threatening symptoms. The first reported case of laryngeal granuloma was by Clausen in 1932.4 Since that time, numerous reports and investigations of the possible etiologies, predisposing factors, pathogenesis, prophylaxis, and treatment have been discussed.
Blanc and Tremblay2 performed a comprehensive study of the complications of tracheal intubation by separating the administration of an inhalational general anesthetic into three distinct phases. These phases included the act of placing the endotracheal tube, the period of time that the tube was in place, and extubation. By distinguishing these phases, etiologic factors were then enumerated as predisposing, adjuvant, and decisive.
Predisposing factors consist of age, gender, anatomic characteristics, and fragility of the laryngotracheal mucosa. Adult females are more likely to develop granulomas, as are patients who are obese, have a short neck, or possess other congenital anomalies involving the airway.2 Of these factors, gender was the only one associated with this case report.
Barton5 similarly studied cases of laryngeal granuloma and divided decisive causes into three categories: endolaryngeal trauma, extralaryngeal trauma, or infection. The majority of these cases appear endolaryngeal in origin. One such cause is traumatic intubation, whereby the tube is forced between the adducted cords, thus causing abrasion as it passes into the subglottic region. In addition, the use of an oversized tube or excessive cuff pressure can produce trauma and possible ischemia of the tracheal wall.6 Utilizing a nasal route for intubation may offer greater stability of the endotracheal tube, as compared with oral intubation where subtle movements of the tube may transmit increased stress to the larynx and trachea. 1"7 The nasal passage and nasopharynx inhibit movements of this type, which are of particular importance in oral and maxillofacial surgery when head position is frequently changed intraoperatively.
Another decisive factor can be excessive cuff pressure, especially in the presence of nitrous oxide. It has been shown that an enclosed gas-filled cavity in the body will expand if it contains a gas (nitrogen) that is less soluble in blood than the respired gas (nitrous oxide).89 Because an air-inflated endotracheal tube cuff within the trachea represents an enclosed gas-filled cavity in the body, the cuff is therefore susceptible to overexpansion secondary to the diffusion of nitrous oxide into it. Stanley et al'0 demonstrated that a significant volume change does occur when the tube's cuff is exposed to nitrous oxide. The resultant pressure increase can be sufficient to cause glottic and subglottic trauma. These findings illustrate the importance of monitoring cuff pressure and periodically deflating the cuff in order to avoid excessive cuff volume and pressure during the administration of nitrous oxide.
Tube position in the larynx plays a significant role in the production of extralaryngeal trauma. Head position is probably the most determining factor; patients usually lie supine with the head slightly hyperextended, which tends to direct the tube anteriorly. 1 Studies indicate that lesions are principally located in the dorsolateral region of the larynx.3 Another extralaryngeal contribution involves the duration of time that the patient remains intubated. Prolonged intubation, which can range from as little as 8 hr to months, can cause trauma to the laryngeal mucosa. This is further compounded by movement of the patient, coughing, and swallowing.5 The 18 hr of intubation in the present case was probably contributory to subsequent granuloma formation.
Even following a minimally traumatic intubation, infection can result in an area where the tissue becomes abraded. Inoculation of the area by utilizing unsterile tubes or intubation equipment can result in subsequent infection and eventual granuloma formation.
Pathogenesis of laryngeal granuloma is believed to involve inflammation of the laryngeal mucosa as a sequelae to one of the aforementioned causes. This inflamed area then ulcerates secondarily and ultimately becomes a sessile granuloma. The granuloma then becomes pedunculated as the periphery fibroses. Finally, healing occurs via epithelialization after spontaneous rejection or surgical removal. 5 The principal sign of a developing laryngeal granuloma is hoarseness. Any postoperative hoarseness lasting more than a week should be investigated. A feeling of fullness in the throat is another common complaint. Dysphonia, difficulty breathing, or a persistent sore throat are other indications for further evaluation by a laryngologist."1"2 Usually these lesions manifest from a few weeks to a few months after tracheal intubation.13 Ulcers over the vocal processes and posterolateral cricoid are common autopsy findings. Such ulcers are noted as early as 7 hr after intubation. 14 Treatment consists of surgical removal under direct laryngoscopy if the lesion has reached the pedunculated stage and is causing respiratory embarrassment. The granuloma will most often be ejected at this stage during an episode of coughing. Removal at the sessile stage is contraindicated due to the high incidence of recurrence. 12,15 The recuperative phase must include vocal rest; otherwise continued adduction of the cords will lead to abrasion in the midline, which can result in bilateral ulceration and subsequent bilateral granuloma formation. Prevention primarily involves avoiding or eliminating the etiolgoic factors previously mentioned. Atraumatic intubation under direct visualization during laryngoscopy minimizes trauma to the cords. Utilization of smaller endotracheal tubes, attention to cuff pressure, prevention of excessive flexion or extension of the neck, and the use of muscle relaxants and/or adequate depth of anesthesia to avoid reflexive movements around the tube are measures that should be applied consistently to reduce the incidence of this and other complications associated with endotracheal intubation.1,5,2