Abstract
Tonsillectomy, with or without adenoidectomy, is one of the most frequently performed surgical procedures in the United States, with more than 700,000 cases completed per year. Many patients have medical comorbidities that must be optimized preoperatively, and the potential for perioperative complications must be thoroughly under Complications can be serious and at times life-threatening. The proper selection of patients and attention to anesthetic risk and technique can reduce this risk and complications. Complications are most frequently encountered in children younger than 3 years of age and those with documented sleep disordered breathing.
Keywords
obstructive sleep apnea syndrome, Post tonsillectomy hemorrhage, post tonsillectomy inpatient admission, postoperative pain management, postoperative pulmonary edema
Case Synopsis
An obese 3-year-old boy (body mass index 30) with obstructive sleep apnea (apnea hypopnea index 10) presents for tonsillectomy and adenoidectomy. In the postanesthesia care unit, his respiratory rate is 10 breaths per minute with significant respiratory pauses, and his heart rate is 140 beats per minute. A small amount of blood is noted in the oropharynx, and he has bilateral rales on auscultation. Oxygen saturation by pulse oximetry is 86%.
Problem Analysis
Definition
Tonsillectomy, with or without adenoidectomy, is one of the most frequently performed surgical procedures in the United States, with more than 700,000 cases completed per year. Many patients have medical comorbidities that must be optimized preoperatively, and the potential for perioperative complications must be thoroughly understood. The vast majority of children do well after surgery; however, complications can be serious and at times life threatening. The risk of death after tonsillectomy in all patients is 1:10,000. The proper selection of patients and attention to anesthetic risk and technique can reduce this risk and complications related to the following factors:
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Bleeding
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Young age
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Postoperative pulmonary edema
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Postoperative pain
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Obstructive sleep apnea
Recognition
Bleeding
Postoperative hemorrhage occurs in 0.1% to 8.1% of patients. In 75% of cases, bleeding occurs within 6 hours of surgery and is usually the result of surgical technique; in the remaining 25%, it can occur as late as the eighth postoperative day and is related to sloughing of the postoperative eschar. Most bleeding is noted by blood-stained sputum or the vomiting of “coffee grounds” material.
Young Age
In the past, all children were admitted to the hospital postoperatively after tonsillectomy for management of vomiting, dehydration, bleeding, pain, and apnea. The advent of cost containment, along with a trend toward ambulatory surgery, has changed this practice. Recent guidelines suggest that only children age 3 years or younger are routinely admitted to the hospital after tonsillectomy, in addition to those who have severe obstructive sleep apnea syndrome (OSAS) (apnea-hypopnea index of 10 or more obstructive events per hour), oxygen saturation nadir less than 80%, or both.
Pulmonary Edema
Pulmonary edema may present as frothy pink fluid in the endotracheal tube, decreased oxygen saturation, wheezing, dyspnea, or increased respiratory rate after tracheal extubation. The differential diagnosis of postobstruction pulmonary edema includes aspiration of gastric contents, respiratory distress syndrome, congestive heart failure, volume overload, and anaphylaxis. A chest radiograph illustrating diffuse, usually bilateral, interstitial pulmonary infiltrates, combined with an appropriate clinical history, confirms the diagnosis.
Postoperative Pain
Pain is minimal after adenoidectomy but often severe after tonsillectomy. The combined effects of irritant blood in the stomach, interference with the gag reflex caused by edema, and stimulation of receptors in the chemoreceptor trigger zone contribute to postoperative vomiting, which can occur in up to 70% of tonsillectomy patients who do not receive prophylactic antiemetic therapy.
Obstructive Sleep Apnea
Hypertrophied tonsils may obstruct the upper airway during sleep, causing OSAS in approximately 3% to 12% of children. The highest incidence is in children younger than 5 years of age. The definitive diagnosis of OSAS is confirmed by polysomnography, which is a graphic record of respiratory activity during natural sleep; however, it is not feasible to test every child suspected of OSAS and sleep-disordered breathing. For this reason many authors have attempted to design a pediatric preoperative questionnaire to facilitate the diagnosis of OSAS in the same way the STOP-BANG questionnaire has been validated in the adult population. A positive sleep study is an indication for tonsillectomy, especially if related systemic abnormalities are present. The clinical presentation of OSAS is quite varied. Some patients have significant limitations, whereas others are minimally affected ( Box 30.1 ).
Young age (<6 years old)
Snoring during sleep
Failure to thrive
Recurrent respiratory tract infections
Craniofacial dysmorphism
Cardiac arrhythmias
Apnea during sleep
Somnolence while awake
Developmental delay
Obesity
Behavioral difficulty
Cor pulmonale
Risk Analysis
Bleeding
The tonsillar fossa, nasopharynx, or both are the sites for 67%, 27%, or 6% of postoperative bleeding, respectively.
Young Age
Age younger than 3 years is the most significant risk factor for the development of respiratory compromise after adenotonsillectomy. Respiratory compromise is defined as oxygen saturation less than 90%, with an obstructive breathing pattern or acute respiratory distress requiring intervention.
Pulmonary Edema
Factors that increase venous return and preload in either ventricle, or those that reduce the ability of the pulmonary lymphatic system to acutely remove large amounts of fluid, increase the risk of postobstruction pulmonary edema. Postoperative laryngospasm and breathing against a closed glottis cause negative transpulmonary pressures, leading to an increased hydrostatic gradient and subsequent pulmonary edema.
Postoperative Pain and Vomiting
Significant differences in the degree of postoperative pain are related to the surgical technique of tonsil removal. Increased pain medication requirements, otalgia, and irritability have been observed in patients undergoing tonsillectomy with electrocautery and laser excision compared with sharp dissection. Tonsillotomy, or partial tonsillectomy, is being increasingly used as an alternative therapy due to evidence suggesting lower rates of postsurgical hemorrhage and decreased pain compared with tonsillectomy. Vomiting is multifactorial and may be due in part to the stimulation of vagal mediators in the hypopharynx, as well as systemic serotonin release.
Obstructive Sleep Apnea
The degree of tonsillar hypertrophy does not correlate with the severity of upper airway obstruction in patients with OSAS. Children with only slightly enlarged tonsils may have severe OSAS, whereas those with very enlarged tonsils may not have OSAS at all. The risk for OSAS increases with changes in the nasopharyngeal airway and obesity. Children with OSAS have a narrowed aperture of the nasopharyngeal airway, so posterior displacement of the tongue causes hypopharyngeal obstruction. Up to 60% of children affected with OSAS are obese, and it has been suggested that there is a need to develop a specific OSAS screening questionnaire for obese children. Fatty infiltration of the neck, along with relaxation of the pharyngeal muscles, compounds obstruction, because the collapsing force of negative inspiratory pressure exceeds the expanding force of pharyngeal muscular contraction. These children are at risk for respiratory related adverse events, as well as being more sensitive to the respiratory depressant effects of opioids.
Implications
Bleeding
Posttonsillectomy bleeding may be controlled by the application of topical agents to promote coagulation. However, most episodes require surgical exploration and treatment. Large volumes of blood may be swallowed but not appreciated by the patient, parents, or surgeon. Therefore all posttonsillectomy patients with tonsillar hemorrhage are considered to have a full stomach, and appropriate anesthetic precautions must be taken. Because the amount of swallowed blood is usually underappreciated, examination for orthostatic hypotension as a measure of intravascular volume adequacy is required.
Young Age
Children younger than 3 years are at increased risk for inadequate oral intake and subsequent dehydration immediately following surgery. They are also at increased risk for postoperative respiratory compromise.
Pulmonary Edema
Pulmonary edema can occur when airway obstruction is relieved by tonsillectomy. It has been suggested that increased negative inspiratory pressure consequent to airway obstruction increases venous return and pulmonary blood volume ( Fig. 30.1 ). Peak negative inspiratory intrapleural pressure, which is normally 2.5 to 10 cm H 2 O, increases to 30 cm H 2 O with airway obstruction. A negative transpulmonary pressure gradient of this magnitude can disrupt the integrity of the pulmonary capillary walls. Concurrently, increased pulmonary blood flow and hydrostatic pressure facilitate transudation of fluid into the alveolar space. To counteract this, positive intrapleural and alveolar pressure is generated during exhalation (similar to the expiratory grunt or Valsalva maneuver). This reduces pulmonary venous return and blood volume. Relief of airway obstruction after tonsillectomy reduces airway pressure, but it also increases venous return and pulmonary hydrostatic pressure. This can lead to hyperemia and ultimately pulmonary edema. Bear in mind that the counterbalancing effect of the expiratory grunt to limit pulmonary venous return is lost with relief of airway obstruction.
