SECTION V. Intrathoracic and Extrathoracic
A Breast Biopsy
1. Introduction
Breast cancer is diagnosed by excisional breast biopsy (by needle aspiration or open excision), followed later by a more definitive surgical procedure designed to decrease tumor bulk and thus enhance effectiveness of systemic therapy (chemotherapy, hormonal therapy, or radiation). Carcinoma of the breast is an uncontrolled growth of anaplastic cells. Types include ductal, lobular, and nipple adenocarcinomas.
2. Preoperative assessment and patient preparation
a) History and physical examination
(1) The most common initial sign of carcinoma of the breast is a painless mass.
(2) Bloody discharge is more indicative of cancer than is spontaneous unilateral serous nipple discharge.
(3) Signs of advanced breast cancer include dimpling of skin, nipple retraction, change in breast contour, edema, and erythema of the breast skin.
b) Diagnostic tests
(1) Mammography, thermography, and ultrasonography are used.
(2) Metastases to bone are frequent; therefore, a bone scan and measurement of alkaline phosphatase may be indicated.
(3) Laboratory tests are as indicated by the patient’s medical condition.
c) Preoperative medications and intravenous therapy
(1) The patient may be receiving hormone therapy.
(2) Use light sedation and short-acting narcotics preoperatively because the procedure lasts less than 1 hour.
(3) One 18-gauge intravenous line with minimal fluid replacement is used.
3. Room preparation
a) Monitoring equipment
(1) Standard
(2) Noninvasive blood pressure cuff on the side opposite of surgery
b) Pharmacologic agents: Standard
c) Position: Supine; may need to tuck the surgical arm to the side
4. Anesthetic technique
a) Local infiltration and general anesthesia are used.
b) The technique of choice is general anesthesia with mask technique.
5. Perioperative management
a) Induction: Consider rapid sequence induction and endotracheal intubation with a patient who is obese or has a full stomach.
b) Maintenance: No indications are needed.
c) Emergence: If rapid sequence induction is used, perform an awake extubation.
B Bronchoscopy
1. Introduction
Bronchoscopy permits direct inspection of the larynx, trachea, and bronchi. Indications include collection of secretions for cytologic or bacteriologic examination, tissue biopsy, location of bleeding and tumors, removal of a foreign body, and implantation of radioactive gold seeds for tumor treatment. A common indication for bronchoscopy is suspicion of bronchial neoplasm.
2. Preoperative assessment
a) History and physical examination
(1) Respiratory: Evaluate for chronic lung disease, wheezing, atelectasis, hemoptysis, cough, unresolved pneumonia, diffuse lung disease, and smoking history.
(2) Cardiac: Question underlying dysrhythmias because they may arise with stimulation from the scope, or they could be a sign of hypoxemia during the procedure.
(3) Gastrointestinal: Assess the patient’s drinking history and nutritional intake.
b) Diagnostic tests
(1) Chest radiography
(2) Computed tomography
(3) Pulmonary function test with lung disease
(4) Laboratory tests including complete blood count, electrolytes, glucose, and others as indicated by the patient’s medical condition.
c) Preoperative medications and intravenous therapy
(1) The patient may already be taking sympathomimetic bronchodilators and aminophylline.
(2) Sedatives and narcotics are to be used with caution in patients with poor respiratory reserve.
(3) Cholinergic blocking agents reduce secretions.
(4) Intravenous lidocaine, 0.5 to 1.5 mg/kg, decreases airway reflexes.
(5) Topical anesthesia involves 4% lidocaine using a nebulizer to anesthetize the airway by spraying the palate, pharynx, larynx, vocal cords, and trachea.
(6) One 18-gauge peripheral intravenous line with minimal fluid replacement is used.
3. Room preparation
a) Monitoring equipment is standard: An arterial line is used if thoracotomy is planned or the patient is unstable.
b) Pharmacologic agents: Lidocaine and cardiac drugs are used.
c) Position: Supine; the table may be turned. One must manage an upper airway that is shared with the surgeon.
4. Anesthetic technique
a) Local infiltration or general anesthesia is used.
b) The technique of choice is general anesthesia. One must discuss with the surgeon whether a rigid or flexible fiberoptic bronchoscopy will be performed (see the following box).
Consideration for Rigid versus Fiberoptic Bronchoscopy
Rigid
1. Has been used extensively for removal of foreign bodies
2. In moderate or massive hemoptysis, provides better opportunity to suction
3. When airway patency is compromised by granulation tissue or tumor, instrument is able to pass the point of obstruction
4. Preferred for visualization of the carina and for the assessment of its mobility and sharpness
5. Allows the endoscopist to obtain a larger bronchoscopy specimen
6. Preferred in infants and small children
Fiberoptic
1. May require fragmentation of the aspirated object
2. Provides a better yield than rigid bronchoscopy in diagnosing bronchogenic carcinoma
3. Allows detailed visualization of the tracheobronchial tree
4. Facilitates intubation in patients who have difficult anatomic features
5. Improves patient comfort
6. Provides video imaging
c) Nerve blocks
(1) Transtracheal: 2 mL of 2% plain lidocaine through the cricothyroid membrane using a 22-gauge needle attached to a small syringe
(2) Superior laryngeal: 25-gauge needle anterior to the superior cornu of the thyroid cartilage
d) If topical anesthesia is employed, consider total dosage of local anesthetic and be prepared to treat local anesthetic toxicity.
5. Perioperative management
a) Induction
(1) Flexible bronchoscopy
(a) The endotracheal tube must be large enough (8 to 8.5 mm) to permit the endoscope to pass easily.
(b) Do not administer oxygen through the suction channel of the flexible bronchoscope (to avoid gas trapping and inducing barotrauma).
(2) Rigid bronchoscopy
(a) Conventional ventilation
(i) Ventilation through the side port requires high gas flow rates and an intact glass eyepiece.
(ii) Suction, biopsy, and foreign-body manipulation require removal of the glass and loss of ventilation.
(b) Jet ventilation
(i) Give patients high inspired oxygen and hyperventilate them before apneic oxygenation.
(ii) Perform jet ventilation through the side port of a catheter alongside the bronchoscope.
(iii) Place the tracheal tube to the left side of the mouth because the surgeon will insert the scope down the right side.
(iv) The endotracheal tube must be smaller in diameter to allow surgical access.
(3) After preoxygenation, general anesthesia is induced with the insertion of an oral endotracheal tube.
(4) Succinylcholine may be contraindicated if the patient has severe muscle spasm, wasting, or complains of myalgia.
b) Maintenance
(1) General anesthesia must provide good muscle relaxation without patient movement: coughing, laryngospasm, or bronchospasm.
(2) Cardiac dysrhythmia may be a problem (i.e., supraventricular tachyarrhythmias, premature ventricular contraction, and atrial dysrhythmias). Plan appropriate treatment modalities.
(3) Volatile anesthetics are useful to provide adequate suppression of upper airway reflexes and permit high inhaled concentrations of oxygen.
(4) Air leaks around the bronchoscope may be minimized by having an assistant externally compress the patient’s hypopharynx.
(5) Spontaneous ventilation is preferred in cases of foreign body removal; positive airway pressure could push the foreign body deeper into the bronchial tree.
c) Emergence
(1) The patient should be awakened rapidly with complete return of airway reflexes before extubation.
(2) The patient needs to have a cough to clear secretions and blood from the airway.
6. Postoperative implications
a) If nerve blocks are administered, keep the patient from eating or drinking for several hours postoperatively; the blocks cause depression of airway reflexes.
b) Subglottic edema may be treated with aerosolized racemic epinephrine and intravenous dexamethasone (0.1 mg/kg).
c) Chest radiographs are obtained to detect atelectasis or pneumothorax.
7. Complications
A toxic reaction to local anesthetic is possible.
C Bullae
1. Introduction
Bullae are air-filled spaces of lung tissue resulting from the destruction of alveolar tissues and consolidation of alveoli into large pockets. They offer low resistance to inspiration and tend to increase in size with positive pressure ventilation. A valvelike mechanism may be present that causes air trapping on expiration. Enlarging bullae compress normal lung tissue and vasculature to the point of causing hypoxemia, polycythemia, and cor pulmonale. Overdistended bullae can rupture and cause pneumothorax or tension pneumothorax with cardiopulmonary collapse, requiring insertion of a chest tube. A chest tube may show a large, continuous air leak, and ventilation may be difficult.
2. Anesthetic considerations
a) A double-lumen tube (DLT) is indicated when a thoracotomy is planned to resect bullous tissue. This allows for separate ventilation of each lung and the ability to use adequate V ts on the healthy lung without risking further rupture of bullae.
b) In the event of a pneumothorax, the unaffected lung can be ventilated while a chest tube is placed or the incision is made. When the surgery is nearing completion, each lung can be separately checked for air leaks.
c) During general anesthesia for bullous disease, spontaneous ventilation is desirable until the chest is opened to reduce the risk of rupture of bullae.
Patients with severe cardiopulmonary disease may not be able to ventilate adequately under general anesthesia, however, and positive pressure ventilation may be required.
d) Small V ts, high respiratory rates, and high F io2 can be delivered by gentle manual ventilation to keep airway pressures below 10 to 20 cm H 2O.
e) An alternative to positive pressure ventilation is high-frequency jet ventilation, used to decrease the chance of barotrauma.
f) Nitrous oxide should be avoided in bullous disease because it rapidly enlarges the air-filled spaces.
g) The choice of other anesthetic agents depends on the patient’s cardiopulmonary status and the anesthesia provider’s desire to maintain spontaneous ventilation.
h) After excision of the bulla, normal lung tissue rapidly expands, and compliance and gas exchange rapidly improve. Care must still be taken with positive pressure ventilation if some unresectable bullae remain.
D Mastectomy
1. Introduction
Total mastectomy (simple or complete mastectomy) removes only the breast; no axillary node dissection is involved. It is used for the treatment of ductal carcinoma in situ. Radical mastectomy involves removal of the breast, underlying pectoral muscles, and axillary lymph nodes. There are two major alternatives to radical mastectomy: modified radical mastectomy and wide local excision of the tumor (partial mastectomy or lumpectomy) with axillary dissection. This treatment is followed by postoperative radiation therapy to the remaining breast.
2. Preoperative assessment
Patients often have no other underlying medical problems. The anesthetic implications of metastatic spread to bone, brain, liver, lung, and other areas should be considered. Preoperative assessment should be routine, with special consideration to the following:
a) Cardiac: Cardiomyopathies may result from chemotherapeutic agents (e.g., doxorubicin at doses greater than 75 mg/m 2). Patients exposed to this type of drug may experience cardiac dysfunction, and a cardiac consultation may be needed to determine ventricular function.
b) Respiratory: If the patient has undergone radiation therapy, there may be some respiratory compromise. Drugs such as bleomycin (greater than 200 mg/m 2) can cause pulmonary toxicity and necessitate administration of a low fractional inspiration of oxygen (0.30).
c) Neurologic: Breast cancer often metastasizes to the central nervous system, and there could be signs of focal neurologic deficits, altered mental status, or increased intracranial pressure. If mental status is altered, a full medical workup should be undertaken without delay. Postpone surgery until the cause is found.
d) Hematologic: The patient may be anemic secondary to chronic disease or chemotherapeutic agents.
3. Room preparation
Monitors and equipment are standard. If the procedure is for a superficial biopsy, monitored anesthesia care with sedation can be used. Be sure to place the blood pressure cuff on the arm opposite the operative site. The patient is placed in the supine position during the procedure.
4. Perioperative management and anesthetic technique
a) Routine induction and maintenance are used.
b) Pressure dressings are often applied with the patient anesthetized and “sitting up” at the conclusion of the procedure. Communicate with the surgeon if this type of dressing will be used, to time emergence more appropriately. If there are no further considerations, the patient may be extubated in the operating room.
5. Complications
a) Deep surgical exploration may inadvertently cause a pneumothorax. The patient should be monitored for signs and symptoms of pneumothorax, which include increased peak inspiratory pressures, decreased arterial carbon dioxide pressure, asymmetric breath sounds, hemodynamic instability, and hyperresonance to percussion over the affected side.
b) Diagnosis is concluded by a chest radiograph.
c) Treatment includes placing the patient on a fractional inspired oxygen of 100% and insertion of a chest tube.
6. Postoperative implications
a) If the patient is unstable hemodynamically (which may suggest a tension pneumothorax), place a 14-gauge angiocatheter in the second intercostal space while the surgeons prepare for chest tube placement.
b) A postoperative chest radiograph may be needed if a pneumothorax is suspected.
E Mediastinal Masses
1. Introduction
Masses in the mediastinum can compress vital structures and cause changes in cardiac output, obstruction to air flow, atelectasis, or central nervous system changes. Masses can include benign or cancerous tumors, thymomas, substernal thyroid masses, vascular aneurysms, lymphomas, and neuromas. Surgical procedures for diagnosis or treatment of these masses may include thoracotomy, thoracoscopy, and mediastinoscopy.
Tumors within the anterior mediastinum can cause compression of the trachea or bronchi, increasing resistance to air flow. Changes in airway dynamics with supine positioning, induction of anesthesia, and positive pressure ventilation can cause collapse of the airway with total obstruction to flow. Manipulation of tissue intraoperatively, edema, and bleeding into masses can increase their size and effects on airways or vasculature. As a result, total airway obstruction can occur at any phase of anesthesia: positioning, induction, intubation, emergence, or recovery. Positive pressure ventilation may be impossible even with a properly placed endotracheal tube, if the mass encroaches on the airway distal to the endotracheal tube. Localization of the mass by computed tomography or bronchoscopy may facilitate placement of the endotracheal tube distal to the mass. Maintenance of spontaneous ventilation retains normal airway-distending pressure gradients and can maintain airway patency when positive pressure will not. Maintenance of spontaneous ventilation is the goal when managing these patients.
2. Clinical manifestations
Signs and symptoms of respiratory tract compression should be sought preoperatively. Many mediastinal masses are asymptomatic, or characterized by vague signs such as dyspnea, cough, hoarseness, or chest pain. The common symptoms are listed in the following box.
Symptoms of Mediastinal Mass
Sweats
Syncope
Orthopnea
Hoarseness
Inability to lie flat
Chest pain or fullness
Superior vena cava obstruction
Cough (especially when supine)
a) Wheezing may represent air flow past a mechanical obstruction rather than bronchospasm.
b) Shortness of breath at rest or with exertion and coughing are other symptoms.
Symptoms may be positional, worsening in the supine or other position.
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