Intrathoracic and extrathoracic
A Breast biopsy
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 the 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 Bronchoscopy
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.
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 could be a sign of hypoxemia during the procedure.
(3) Gastrointestinal: Assess the patient’s drinking history and nutritional intake.
(3) Pulmonary function test with lung disease
(4) Laboratory tests, including a complete blood count, electrolytes, glucose, and others as indicated by the patient’s medical condition
c) Preoperative medications and intravenous (IV) therapy
(1) The patient may already be taking sympathomimetic bronchodilators and aminophylline. The patient may benefit from administration of an inhaled bronchodilator preoperatively.
(2) Sedatives and narcotics are to be used with caution in patients with poor respiratory reserve.
(3) Cholinergic blocking agents reduce secretions.
(4) IV 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 IV line with minimal fluid replacement is used.
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.
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 box on pg. 350).
(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 used, consider total dosage of local anesthetic and be prepared to treat local anesthetic toxicity.
(a) The endotracheal tube (ETT) must be large enough (8–8.5 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).
(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.
(i) Give patients high fraction of 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 ETT must be smaller in diameter to allow surgical access.
(v) Consider total IV anesthesia when using jet ventilation.
(3) After preoxygenation, general anesthesia is induced with the insertion of an oral ETT.
(4) Succinylcholine may be contraindicated if the patient has severe muscle spasm, wasting, or complains of myalgia.
(1) General anesthesia must provide good muscle relaxation without patient movement such as coughing, laryngospasm, or bronchospasm. Because of the extensive sensory innervation in the trachea and bronchi, a deep plane of anesthesia must be maintained to avoid coughing, bucking, and exaggerated hemodynamic response.
(2) Cardiac dysrhythmia (i.e., supraventricular tachyarrhythmias, premature ventricular contraction, and atrial dysrhythmias) may be a problem. Plan appropriate treatment modalities.
(3) Inhalation 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.
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 2.25% (0.05 mL/kg) and IV dexamethasone (0.1 mg/kg).
c) Chest radiographs are obtained to detect atelectasis or pneumothorax.
d) Complications: A toxic reaction to local anesthetic is possible.
C Bullae
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.
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 tidal volumes (Vts) 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, and positive-pressure ventilation may be required.
d) Small Vts, high respiratory rates, and high Fio2 can be delivered by gentle manual ventilation to keep airway pressures below 10 to 20 cm H2O.
e) An alternative to positive-pressure ventilation is high-frequency jet ventilation, which is 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 bullae, 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
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.
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 such as doxorubicin (>550 mg/m2). 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 (>200 mg/m2) can cause pulmonary toxicity and necessitate administration of a low fractional of inspired oxygen (<0.30). However, a higher fraction of inspired oxygen is warranted if necessary to keep SpO2 at 88% to 92% or greater.
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. Surgery should be postponed until the cause is found.
d) Hematologic: The patient may be anemic secondary to chronic disease or chemotherapeutic agents.
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.
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) Postoperative chest radiography may be needed if a pneumothorax is suspected.
(1) 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.
(2) Diagnosis is concluded by chest radiography.
(3) Treatment includes placing the patient on a fractional inspired oxygen of 100% and insertion of a chest tube.
E Mediastinal masses
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, including during positioning, induction, intubation, emergence, or recovery. Positive pressure ventilation may be impossible even with a properly placed ETT if the mass encroaches on the airway distal to the ETT. Localization of the mass by computed tomography (CT) or bronchoscopy may facilitate placement of the ETT 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.
Signs and symptoms of respiratory tract compression should be sought preoperatively. Many patients with 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.
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.
