Anesthesia for Esophageal Surgery

Anesthesia for Esophageal Surgery

PREOPERATIVE CONSIDERATIONS

Common indications for esophageal surgery include tumors, gastroesophageal reflux, and motility disor-ders (achalasia). Surgical procedures include simple endoscopy, esophageal dilatation, cervical esoph-agomyotomy, open or thoracoscopic distal esoph-agomyotomy, insertion or removal of esophageal stents, and esophagectomy. Squamous cell carcino-mas account for the majority of esophageal tumors; adenocarcinomas are less common, whereas benign tumors (leiomyomas) are rare. Most tumors occur in the distal esophagus. Operative treatment may be palliative or curative. Although the prognosis is generally poor, surgical therapy offers the only hope of a cure. After esophageal resection, the stomach is pulled up into the thorax, or the esopha-gus is functionally replaced with part of the colon (interposition).

Gastroesophageal reflux is treated surgi-cally when the esophagitis is refractory to medi-cal management or results in complications such as stricture, recurrent pulmonary aspiration, or Barrett’s esophagus (columnar epithelium). A variety of antireflux operations may be performed (Nissen, Belsey, Hill, or Collis–Nissen) via tho-racic or abdominal approaches, often laparoscopi-cally. They all involve wrapping part of the stomach around the esophagus. Achalasia and systemic sclerosis (scleroderma) account for the majority of surgical procedures per-formed for motility disorders. The former usually occurs as an isolated finding, whereas the latter is part of a generalized collagen–vascular disorder. Cricopharyngeal muscle dysfunction can be associ-ated with a variety of neurogenic or myogenic dis-orders and often results in a Zenker’s diverticulum.

ANESTHETIC CONSIDERATIONS

Regardless of the procedure, a common anes-thetic concern in patients with esophagealdisease is the risk of pulmonary aspiration. This may result from obstruction, altered motility, or abnormal sphincter function. In fact, most patients typically complain of dysphagia, heartburn, regurgi-tation, coughing, and/or wheezing when lying flat. Dyspnea on exertion may also be prominent when chronic aspiration results in pulmonary fibrosis. Patients with malignancies may present with ane-mia and weight loss. Esophageal cancer patients usually have a history of cigarette smoking and alcohol consumption, so patients should be evalu-ated for coexisting chronic obstructive pulmonary disease, coronary artery disease, and liver dysfunc-tion. Patients with systemic sclerosis (scleroderma) should be evaluated for involvement of other organs, particularly the kidneys, heart, and lungs; Raynaud’s phenomena is also common.

In patients with reflux, consideration should be given to administering metoclopramide, an H₂-receptor blocker, or a proton-pump inhibitor preoperatively. In such patients, a rapid-sequence induction should be used. A double-lumen tube is used for procedures involving thoracoscopy or tho-racotomy. The anesthesiologist may be asked to pass a large-diameter bougie into the esophagus as part of the surgical procedure; great caution must be exer-cised to help avoid pharyngeal or esophageal injury.

Transhiatal (blunt) and thoracic esophagec-tomies deserve special consideration. These pro-cedures often involve considerable blood loss. The former requires an upper abdominal incision and a left cervical incision, whereas the latter requires pos-terolateral thoracotomy, an abdominal incision, and, finally, a left cervical incision. Parts of the proce-dure may be performed using laparoscopy or VATS. Monitoring of arterial and central venous pressure is indicated. Multiple large-bore intravenous access, fluid warmers, and a forced-air body warmer are advisable. During the trans hiatal approach to esoph-agectomy, substernal and diaphragmatic retractors can interfere with cardiac function. Moreover, as the esophagus is freed up blindly from the poste-rior mediastinum by blunt dissection, the surgeon’s hand transiently interferes with cardiac filling and produces profound hypotension. The dissection can also induce marked vagal stimulation.

Colonic interposition involves forming a pedi-cle graft of the colon and passing it through the pos-terior mediastinum up to the neck to take the place of the esophagus. This procedure is lengthy, and maintenance of an adequate blood pressure, cardiac output, and hemoglobin concentration is necessary to ensure graft viability. Graft ischemia may be her-alded by a progressive metabolic acidosis.

Postoperative ventilation will often be used in patients undergoing esophagectomy, because so many of them will have coexisting cardiac and pul-monary disease. Postoperative surgical complica-tions include damage to the phrenic, vagus, and left recurrent laryngeal nerves.