Mediastinal haemorrhage mimicking tamponade during en-bloc oesophagectomy

EDITOR: Concealed mediastinal haemorrhage is rare during oesophagectomy procedures. It may occur in patients with major chest trauma following aortic injury. Occasionally patients undergoing aortic arch surgery may present with postoperative mediastinal bleeding. We report a case in which concealed mediastinal haemorrhage complicated an en-bloc oesophagectomy procedure in the early stages of the operation. The diagnosis was not clear because the bleeding was not obvious, as it involved the posterior mediastinum. The mediastinal haemorrhage mimicked cardiac tamponade and was unresponsive to fluid replacement. A 60-yr-old male, ASA III, with oesophageal cancer, was scheduled to undergo en-bloc oesoph agectomy and colon interposition. Past medical history included hypertension, chronic obstructive pulmonary disease, reflux disease and smoking. The surgical plan included initial exploration of the right chest for mobilization of the oesophagus, followed by abdominal and left-sided neck explorations for completion of en-bloc oesophagectomy. The transverse colon would then be mobilized and interposed in place of the oesophagus. Preoperative preparation included blood gas analysis and pulmonary function tests, which were within normal limits. A dobutamine stress echo was negative for cardiac disease. Following induction of anaesthesia, a 39-G double lumen tube was placed uneventfully. Proper placement was confirmed with auscultation and fibreoptic bronchoscopy. Anaesthesia was maintained with isoflurane and intermittent boluses of fentanyl. In addition to the standard anaesthesia monitors, a radial arterial line and pulmonary artery catheter were placed. Initial pulmonary artery pressures were within the normal range (30/15-32/17 mmHg, pulmonary artery occlusion pressures 12-14 mmHg, central venous pressure (CVP) 8-10 mmHg). Initial blood gases were also in the normal range and pulse oximetry showed a saturation of 100% breathing 50% oxygen. The patient was placed in the left lateral decubitus position, one-lung ventilation was initiated and a right thoracotomy was performed in order to mobilize the stomach and oesophagus. This portion of the procedure lasted for the first 3 h of surgery, during which time blood gases remained in the normal range and the patient required only 50% oxygen to maintain adequate oxygenation. After completion of the mobilization, the thoracotomy incision was closed and the patient turned supine. Blood loss at this portion of the procedure was approximately 250-300 mL. Haemodynamic parameters remained in the normal range. Shortly after turning the patient, the patient became haemodynamically unstable, accompanied by a slowly developing fall in oxygen saturation (99-88%). There was no significant change in peak inflation ventilatory pressures. Auscultation of the lungs revealed no abnormalities. The patient was given 100% oxygen. There was minimal drainage from the right-sided chest tube. The blood pressure (BP) ranged from 60/30 to 70/40 mmHg, and heart rate was 120-130 beats min−1. The oxygen saturation continued to deteriorate in spite of 100% oxygen and ventilation of both lungs. Fibreoptic bronchoscopy revealed no abnormal findings. The hypotension was treated with crystalloid and blood. The patient received 3000 mL crystalloid and albumin 5% 500 mL without any significant improvement in haemodynamics. BP was maintained in the 80/40-90/50 mmHg range with 10 μg kg−1 min−1 of dopamine. There was no evidence of any bleeding at this time, however, haemoglobin analysis revealed a decrease in haemoglobin from 14.0 to 12.0. The patient received three units of packed red blood cells but there was no response. Pulmonary artery pressures were slightly elevated despite the hypotension. There was no evidence of pericardial tamponade (CVP was 12-15 mmHg, pulmonary capillary wedge pressure was 15-17 mmHg). There was no evidence of ischaemic changes on the electrocardiogram. Cardiac output varied from 4.4 to 5.5 L min−1. The patient continued to require increasing inotropic support and fluids to maintain BP. The surgeon was asked to inspect the mediastinum for any signs of mediastinal bleeding via the upper abdominal incision, as the chest incision was already closed. Inspection of the base of the heart did not show any distension and therefore direct tamponade was excluded. An immediate intraoperative chest X-ray showed widening of the mediastinum with an enlarged upper mediastinal opacity extending to the upper zone of the lung. Initially this opacity was diagnosed as upper lobe collapse. The repeat bronchoscopy showed no abnormality with the upper lobe bronchus. A repeat haemoglobin revealed a drop from 12 to 9.5. During this time, the surgeons were exploring the left side of the neck for completion of the oesophagectomy. During the exploration of the neck, it was found that the mediastinum was distended and contained a large haematoma which was causing compression of the mediastinal structures and the upper lobe of the left lung. Approximately 2 L of blood and blood clot were evacuated. Haemodynamics and oxygenation improved shortly after the decompression allowing the dopamine to be discontinued. The site of bleeding was identified as one of the small upper branches of the aorta supplying the oesophagus. The remaining anastomoses were completed. Discussion During surgical procedures, minimal mediastinal bleeding usually does not present with haemodynamic or pulmonary problems. Excessive bleeding may present with haemodynamic compromise. Severe hypotension can be the result of compression of the left atrium, pulmonary veins and superior mediastinal structures, such as the superior vena cava (SVC). The hypoxaemia can possibly be explained by the compression of the left lung by the expanding mediastinum from expanding haemorrhage. There was a reduction in venous return due to compression of the pulmonary veins and left atrium. Reduction in pulmonary perfusion may have compounded the hypoxaemia. Mediastinal haemorrhage may not present with the typical signs of cardiac tamponade. In cardiac tamponade, there is direct compression of the atrium and ventricle from the bleed. In mediastinal haemorrhage, there is compression of the SVC, left atrium, pulmonary vein and left ventricle. Transoesophageal echocardiography can be helpful in the diagnosis but was not feasible in this instance. In the above patient, the mediastinal haematoma exceeded 2 L, which was significant enough to cause mechanical effects on the vessels and result in the above symptoms. Oesophagectomy is becoming a standard procedure for cancer of the oesophagus, achalasia and multiple oesophageal strictures. Transhiatal oesophagectomies are more commonly performed than en-bloc oesophagectomies. In transhiatal oesophagectomies, the mediastinal dissection is performed blindly. During dissection the superior mediastinum may not be visualized completely and it is possible to miss a transected arterial branch which supplies the oesophagus. During the last 10 yr, we have performed approximately 1500 oesophagectomies and have seen two cases of mediastinal haemorrhage which became significant in the postoperative period. In addition to haemodynamic instability, these patients have presented with increased output from the posterior mediastinal drains. This case was unusual in that it occurred during the early part of the dissection and was not readily diagnosed. D. Thangathurai P. Roffey M. Mogos M. Riad A. Bohorquez a1Department of Anesthesiology, University of Southern California, Los Angeles, CA, USA