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Chapter: Clinical Anesthesiology: Anesthetic Management: Anesthesia for Thoracic Surgery

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Special Considerations for Patients Undergoing Lung Resection

Massive hemoptysis is usually defined as >500–600 mL of blood loss from the tracheo-bronchial tree within 24 hr.

\SPECIAL CONSIDERATIONS FOR PATIENTS UNDERGOING LUNG RESECTION

Massive Pulmonary Hemorrhage

Massive hemoptysis is usually defined as >500–600 mL of blood loss from the tracheo-bronchial tree within 24 hr. The etiology is usu-ally tuberculosis, bronchiectasis, or a neoplasm, or complication of transbronchial biopsies. Emergency surgical management with lung resection is reserved for “potentially lethal” massive hemoptysis. In most cases, surgery is usually carried out on an urgent rather than on a true emergent basis whenever pos-sible; even then, operative mortality may exceed 20% (compared with > 50% for medical manage-ment). Embolization of the involved bronchial arter-ies may be attempted. The most common cause of death is asphyxia secondary to blood in the airway. Patients may be brought to the operating room for rigid bronchoscopy when localization is not possible with fiberoptic flexible bronchoscopy. A bronchial blocker or Fogarty catheter (above) may be placed to tamponade the bleeding, or laser coagulation may be attempted.

Multiple large-bore intravenous catheters should be placed. Sedating drugs should not be given to awake, nonintubated, spontaneously ven-tilating patients because they are usually already hypoxic; 100% oxygen should be given continu-ously. If the patient is already intubated and has bronchial blockers in place, sedation is helpful to prevent coughing. The bronchial blocker should be left in position until the lung is resected. When the patient is not intubated, a rapid sequence induc-tion (ketamine or etomidate with succinylcholine) is used. Patients usually swallow a large amount of blood and should be considered to have a full stom-ach. A large double-lumen bronchial tube is ideal for protecting the normal lung from blood and for suctioning each lung separately. If any difficulty is encountered in placing the double-lumen tube, or its relatively small lumens occlude easily, a large (>8.0-inner diameter) single-lumen tube may be used with a bronchial blocker to provide lung isolation.

Pulmonary Cyst & Bulla

Pulmonary cysts or bullae may be congenital or acquired as a result of emphysema. Large bullae can impair ventilation by compressing the surrounding lung. These air cavities often behave as if they have a one-way valve, predisposing them to progressively enlarge. Lung resection may be undertaken for pro-gressive dyspnea or recurrent pneumothorax. The greatest risk of anesthesia is rupture of the air cavity during positive-pressure ventilation, resulting in tension pneumothorax; the latter may occur on either side prior to thoracotomy or on the nonopera-tive side during the lung resection. Induction of anesthesia with maintenance of spontaneous venti-lation is desirable until the side with the cyst or bul-lae is isolated with a double-lumen tube, or until a chest tube is placed; most patients have a large increase in dead space, so assisted ventilation is nec-essary to avoid excessive hypercarbia. The use of N2O is contraindicated in patients withcysts or bullae because it can expand the air space and cause rupture. The latter may be signaled by sudden hypotension, bronchospasm, or an abrupt rise in peak inflation pressure and requires immedi-ate placement of a chest tube.

Lung Abscess

Lung abscesses result from primary pulmonary infections, obstructing pulmonary neoplasms (above), or, rarely, hematogenous spread of sys-temic infections. The two lungs should be isolated to prevent contamination of the healthy lung. A rapid-sequence intravenous induction with tracheal intu-bation with a double-lumen tube is generally recommended, with the affected lung in a depen-dent position. As soon as the double-lumen tube is placed, both bronchial and tracheal cuffs should be inflated. The bronchial cuff should make a tight seal before the patient is turned into the lateral decubitus position, with the diseased lung in a nondependent position. The diseased lung should be frequently suctioned during the procedure to decrease the like-lihood of contaminating the healthy lung.

Bronchopleural Fistula

Bronchopleural fistulas occur following lung resec-tion (usually pneumonectomy), rupture of a pul-monary abscess into a pleural cavity, pulmonary barotrauma, or spontaneous rupture of bullae. The majority of patients are treated (and cured) conser-vatively; patients come to surgery when chest tube drainage has failed. Anesthetic management maybe complicated by the inability to effectively ven-tilate the patient with positive pressure because of a large air leak, the potential for a tension pneu-mothorax, and the risk of contaminating the other lung if an empyema is present. T he empyema isusually drained, prior to closure of the fistula. correctly placed double-lumen tube greatly simplifies anesthetic management by isolating the fistula and allowing one-lung ventilation to the nor-mal lung. The patient should be extubated as soon as possible after the repair.

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