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Laryngeal edema: perioperative nursing considerations. (Best Practice).

Postoperative laryngeal edema is a relatively rare yet serious postoperative complication that can cause significant morbidity, and in severe cases, mortality (Ho, Harn, Lien, Hu, & Wang, 1996). Reports of the incidence of postoperative laryngeal edema vary from 2% to 15%, with one investigation documenting an incidence rate of 4.2% (Darmon et al., 1992). These researchers found that 75% of those patients experiencing laryngeal edema developed symptoms within 8 hours of extubation. Because this period of time extends beyond a patient's customary stay in a post-anesthesia unit, all postoperative nurses must be familiar with the signs, symptoms, and necessary treatment for laryngeal edema.

Recognizing the complications of anesthesia and following management guidelines to ensure patient safety are critically important activities for adult-health nurses working with patients who have undergone anesthesia. Protection of the airway is the fundamental priority for surgical patients following general anesthesia. Therefore, nurses must be mindful that airway compromise can result if resistance to airflow occurs due to postoperative laryngeal edema. Reviewing the mechanisms and risk factors related to laryngeal edema, as well as the nursing considerations involved in the care of patients experiencing this problem, enables nurses to identify and prevent a life-threatening occurrence.

Intubation: Why, What, How

When patients undergo general anesthesia, intubation is necessary to achieve airway control. The term endotracheal intubation correctly describes the placement of the tube into the trachea (see Figure 1). One critical benefit of isolating the airway in this procedure is preventing fluid aspiration into the lung. Nevertheless, aspiration can occur around a cuffed endotracheal tube. Once the patient is intubated, the anesthesiologist or nurse anesthetist can facilitate ventilation and oxygenation, and deliver anesthesic gases during the operative procedure.

[FIGURE 1 OMITTED]

To better understand the process of intubation, the nurse should review the anatomy of the upper airway (see Figure 2). The oropharynx is continuous with the nasopharynx and includes structures such as the palate, tongue, uvula, and palatine tonsils. The laryngopharynx occupies the area from the epiglottis to the esophagus. The role of the epiglottis is to occlude the glottic opening so that food passes safely into the esophagus. The larynx is the junction between the upper and lower airways. A skeleton to the larynx is formed by the cartilage structures of the thyroid, cricoid, and epiglottis. The cricoid cartilage is the only complete ring of cartilage in the trachea and is a common point of reference for access to the trachea in emergency airway situations.

[FIGURE 2 OMITTED]

A laryngoscope and endotracheal tube are used to intubate patients. The laryngoscope is used to observe the larynx and its adjacent structures. The scope has two parts, the handle and blade, which allow for visualization and movement of the soft tissues. The blade varies in shape and size, and its selection can influence post-extubation problems (Stoelting & Miller, 1994). The endotracheal (ET) tube is a transparent plastic device that provides an artificial airway during the delivery of anesthesia. The numerous sizes of ET tubes allow for a good fit between the tube and trachea; markings of internal diameter as well as length assist in the proper sizing and placement of the tube. The ET tube is placed via direct laryngoscopy or other maneuvers through the vocal cords during the intubation process (see Figure 1). An inflatable cuff at the distal end of the tube is filled with air to maintain a seal with the trachea once the tube is in position. This seal allows for the use of positive pressure ventilation and prevents gastric aspiration into the tracheal lumen in the majority of cases. However, use of the seal can lead to postoperative airway edema if tracheal ischemia occurs while the patient is intubated (Stoelting & Miller, 1994).

Standard procedures are used to intubate patients. Prior to intubation, the patient is positioned in the supine position with the head at the top of the bed. Unless contraindicated, the patient's head is extended and the neck is flexed into a "sniffing" position and placed on a firm headrest. The patent's jaw is opened, lips are moved away from the teeth, and the laryngoscope blade is advanced past the tonsils toward the middle of the oral cavity (see Figure 1). The tongue is swept to the side of the mouth to allow visualization of the airway structures and raising of the epiglottis. The vocal cords are then visualized and the ET tube is advanced into the trachea. After the tube is placed, the laryngoscope blade is removed. Breath sounds are auscultated bilaterally and assessed for equality. When correct placement is confirmed, the cuff is injected with air to create a seal. The tube is then taped and connected to the ventilator.

Extubation

Following the surgical procedure, the anesthesiologist or nurse anesthetist determines that the patient has adequate respiratory effort, muscle strength, level of consciousness, and intact airway reflexes. Following this assessment, the process of removing the endotracheal tube, called extubation, is begun. Thorough suctioning is done before deflating the cuff to remove secretions from the trachea, the oropharynx, and the nasopharynx. The patient is ventilated with 100% oxygen, and the cuff is deflated. The patient is asked to take a deep breath, and the tube is gently removed during inspiration. Oxygen is again administered using face mask. Oxygenation is assessed by continuous pulse oximetry and arterial blood gases if available.

Risk Factors for Laryngeal Edema

A number of risk factors contribute to the development of laryngeal edema (Faust, 1991) (see Table 1). As would be expected, a higher incidence of laryngeal edema occurs after multiple intubation attempts or a difficult intubation in which there is excessive airway manipulation or trauma to the tissues. Difficulty with ET tube insertion can occur for a variety of reasons, including the patient's anatomy as well as practitioner and situational factors. Surgery performed on an emergency basis can increase the risk of post-extubation problems if there is related difficulty with intubation. The selection of endotracheal tube size is of utmost importance, because edema can occur if the tube is too large. Overinflation of the cuff can reduce blood flow and cause mucosal ischemia, which also contributes to airway swelling and irritation. Patient coughing, bucking, or swallowing should be prevented during the intubation because these actions can also contribute to edema formation.

Duration of intubation is another factor which increases the risk of postoperative laryngeal edema. Patients undergoing procedures less than an hour in length have a lower incidence of airway obstruction from edema (Benumof & Saidman, 1999). Surgical positioning in the prone position can lead to dependent edema in the airway and oral structures. Procedures frequently performed in this position include those involving the lumbar spine, burn cases receiving exposure to posterior tissues, and a number of plastic surgery approaches. Certain procedures are more likely to cause laryngeal edema because of trauma caused to the surrounding tissue. These include procedures involving the larynx such as head and neck surgery, vocal cord surgery, and resection of airway tumors. During dental procedures and those involving the oral cavity, the ET tube may be manipulated in a way that contributes to a greater likelihood of laryngeal irritation. Any procedure that necessitates large volumes of fluid or blood replacement places the patient at risk of generalized edema, including airway edema. This is more likely to occur in trauma or burn procedures. In rare cases, edema can occur as a systemic allergic response to the tube, lubricant, or other medications given during the operative course. Manifestations of an allergic reaction may not be evident until the case is complete and the patient is recovering postoperatively.

Some evidence suggests that specific patient populations are at a higher risk for laryngeal edema. Older, less-rigorous studies identified obesity, diabetes, and age of 60 years and older as factors which increase risk. In one prospective, randomized, controlled study of post-extubation laryngeal edema (Darmon et al., 1992), duration of intubation and gender were the only definitive risk factors. The incidence of laryngeal edema was significantly greater in patients with longer duration of anesthesia. Seventy percent of the study patients experiencing laryngeal edema were females. Women are presumed to be at greater risk because of a smaller larynx and mucosa that is less resistant to trauma.

Nursing Considerations: Postoperative Assessment

Relatively small changes that result from airway edema can cause large alterations in airway flow. Poiseuille's law states that airflow in a tube-like structure, such as the trachea, is proportional to the radius of the tube (Faust, 1991). When the radius of the trachea is decreased because of swelling, resistance to airway flow increases markedly and adequate spontaneous ventilation becomes much more difficult.

With this understanding, nurses must continuously assess the airway and breathing of every patient who has been intubated when the patient is moved to the post-anesthesia care unit. Breath sounds are auscultated, the patient's appearance is documented, and respiratory rate and quality are noted. In the post-anesthesia unit, it is standard practice to administer oxygen to all patients who have been intubated. They are also placed in the Fowler's position if not contraindicated.

Symptoms of airway edema range from difficulty breathing to stridor. Dyspnea is often accompanied by pulse oximetry and arterial blood gas values demonstrating poor oxygenation and ventilation. It is important to differentiate laryngeal edema and laryngospasm because the treatment for these disorders is different. Laryngeal muscle spasm occurs as a protective reflex to prevent aspiration; it typically occurs from vocal cord manipulation or increased secretions (Waugaman, Foster, & Rigor, 1999). Laryngospasm can cause postoperative airway obstruction due to partial or complete closure of the vocal cords and can mimic laryngeal edema. Although both complications can occur postoperatively, laryngospasm is treated and typically improved with positive pressure ventilation with a bag valve mask device and 100% oxygen. However, patients with laryngeal edema who are treated in this manner will progressively get worse (Waugaman et al., 1999).

Several early signs are indicative of laryngeal edema: decreased breath sounds, a barking or brassy cough, dysphagia, tachycardia, dysphonia, tachypnea, hoarseness, suprasternal retractions, and inspiratory stridor (Marley, 1998). When the nurse assesses the patient and identifies these symptoms, the health care team should act quickly because the edema may continue to progress to a full obstruction.

Nursing Considerations: Postoperative Interventions

Prevention is the first line of defense in post-extubation airway complications. Identifying at-risk patients prior to extubation and at the onset of any difficulty is the primary goal for the health care team. Vigilant monitoring of these and all other patients by the nursing staff enables the early identification of the signs of ensuing laryngeal edema. If laryngeal edema does occur, nurses must attempt to keep the patient calm. Anxiety and restlessness lead to greater oxygen consumption, which increases respiratory rate and causes turbulent airflow that can worsen an obstruction. Unless contraindicated, the patient is placed in the upright position to facilitate ventilation and prevent dependent edema. The administration of humidified oxygen is standard procedure (Waugaman et al., 1999). Racemic epinephrine inhalation treatments are provided to reduce laryngeal mucosal swelling by causing vasoconstriction. This treatment is intended to enlarge the upper airway and facilitate secretion removal. Intravenous steroids may be administered to decrease laryngeal inflammation (Benumof & Saidman, 1999).

If laryngeal edema progresses to impending respiratory failure, positive pressure ventilation is used to minimize airway collapse. A bag-valve mask system is used to perform this procedure. A bag-valve mask system has an oxygen reservoir bag attached to an oxygen source. When the mask is placed over the patient's nose and mouth, the valve system allows the patient to inspire through one valve and expire through another (Davis, Parbrook, & Kenny, 1995). If the airway obstruction progresses in spite of this approach and respiratory failure is impending, reintubation may be attempted. A previously uncomplicated intubation can become impossible if visualization of airway structures is inhibited by edema and patient decompensation.

If the obstruction is near complete edema or if initial supportive efforts to improve ventilation are unsuccessful, emergency transtracheal jet ventilation or cricothyroidotomy may be performed (Benumof & Saidman, 1999). In transtracheal jet ventilation, a 12 to 14-gauge IV catheter is placed into the cricothyroid membrane and high-pressure oxygen is delivered to the patient. Complications of this procedure include subcutaneous emphysema, barotrauma, and blood in the airway (Butterworth, 1992). The cricothyroidotomy involves making a horizontal incision through the cricothyroid membrane and placing an ET tube through the incision into the trachea for ventilation. With either method of securing the airway, verification of placement should be determined by the visualization of the rise and fall of the chest and the auscultation of breath sounds in the lungs and absence of air in the stomach on auscultation (Waugaman et al., 1999).

In cases of severe laryngeal edema, mechanical ventilation may be necessary for a length of 2 to 3 days to allow for edema reduction. Laryngeal healing is indicated by an air leak around the cuff. When laryngeal edema is resolved, continued nursing interventions will support the patient's full recovery. The nurse continues careful assessment of the respiratory system. The patient should be maintained in the Fowler's position with cool humidity. Fluids should be encouraged, and smoke or smoke-filled rooms must be avoided.

Conclusion

Understanding the anatomy of the airway and the processes of intubation and extubation is essential for adult-health nurses caring for patients who will receive or have undergone general anesthesia. If nurses are aware of risk factors that may predispose patients to the development of laryngeal edema, they can be even more alert to the occurrence of symptoms indicating this rare yet serious problem. Maintenance of airway and breathing are always the first priority of patient care, and nurses must be ready to act if laryngeal edema occurs and a patient's airway is compromised.
Table 1.
Postoperative Laryngeal Edema:
Contributory Factors

* Difficult ET tube insertion

* Insertion of an oversized ET
tube

* Overinflation of ET tube cuff

* Long operative procedure

* Procedure performed in the
prone position

* Trauma from resection of
swallowing tissue

* Generalized body edema

* Overagressive fluid
management

* Hematoma formation

* Allergic response


References

Benumof, J., & Saidman, L. (1999). Anesthesia and perioperative complications (2nd ed.). St. Louis: Mosby-Yearbook, Inc.

Butterworth, J. (1992). Atlas of procedures in anesthesia and critical care. Philadelphia: W.B. Saunders Company.

Darmon, J., Rauss, A., Dreyfuss, D., Bleichner, G., Elkharrat, D., Schlemmer, B., Tenaillon, A., Brun-Buisson, C., & Huet, Y. (1992). Evaluation of risk factors for laryngeal edema after tracheal extubation in adults and its prevention by dexamethasone. Anesthesiology, 77, 245-251.

Davis, P., Parbrook, G., & Kenny, G. (1995). Basic physics and measurement in anesthesia (4th ed.). Boston: Butterworth-Heinemann Ltd.

Faust, R. (1991). Anesthesiology review. Mayo Foundation.

Ho, L., Harn, H., Lien, T., Hu, P., & Wang, J. (1996). Postextubation laryngeal edema in adults. Intensive Care Medicine, 22, 933-936.

Marley, R. (1998). Postextubation laryngeal edema: A review with consideration for home discharge. Journal of Perianesthesia Nursing, 13(1), 39-53.

Stoelting, R., & Miller, R. (1994). Basics of anesthesia (3rd ed.). New York: Churchill Livingstone, Inc.

Waugaman, W., Foster, S., & Rigor, B. (1999). Principles and practice of nurse anesthesia (3rd ed.). Stanford: Appleton & Lange.

Marijo Letizia, PhD, RN,C, APN, is an Associate Professor, Loyola University, Chicago, IL.

Jennifer O'Leary, BSN, RN, is a Surgical Staff Nurse, Northwestern Memorial Hospital, Chicago, IL.

Jane Vodvarka, RN, CRNA, is a Nurse Anesthetist, Loyola University Medical Center, Maywood, IL.
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Title Annotation:advice on nursing for postoperative laryngeal edema
Author:Letizia, Marijo; O'Leary, Jennifer; Vodvarka, Jane
Publication:MedSurg Nursing
Date:Apr 1, 2003
Words:2541
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