Urgent cardiopulmonary bypass for the management of intrabronchial descending aortic aneurysm rupture

Introduction

Mycotic thoracic aneurysms in children require prompt surgical repair.^1–3 Rupture into the airways can lead to massive haemoptysis and rapid demise. ⁴ We present a case salvaged by immediate initiation of cardiopulmonary bypass (CPB) and the use of novel perfusion techniques enabling repair via thoracotomy.

Case report

A 14-year-old female presented to a rural hospital with dyspnoea, cough and chest pain. Investigations revealed a suspicious mediastinal mass on X-ray, and high C-reactive protein and glucose levels. She was treated for suspected pneumonia and diabetic ketoacidosis before being transferred to our institution. Locally, a CT scan demonstrated a large saccular aneurysm of the proximal descending aorta with fat stranding along the lesser curvature, severe narrowing of the proximal right and mid left pulmonary arteries, occlusion of the left bronchus and oesophageal compression (Figure 1). Additional testing revealed elevated VDRL titres, suggestive of a syphilitic mycotic aneurysm. Given presence of symptoms, the patient was taken urgently to theatre for repair via a left thoracotomy.OPEN IN VIEWER

In theatre, she was intubated with a 26Fr double-lumen (DL) endotracheal tube (ETT). There were low saturations, poor chest rise and no end-tidal CO₂. Before tube placement could be confirmed, a large volume of blood was noted in the ETT, the DL ETT was replaced with a single lumed ETT to exclude the possibility of misplacement however bleeding became so brisk that it overcame the capacity to suction the ETT clear. A diagnosis of aneurysmal rupture into the airways was made, flooding the lungs and impairing ventilation. The ETT was clamped to limit blood loss, cardiopulmonary resuscitation was started, and the patient was urgently placed onto CPB via the right femoral vein and artery within 23 min of intubation. Haemodynamics were optimized on partial CPB while the remaining monitoring lines were placed.

Next, the patient was repositioned. A left thoracotomy was performed with difficult exposure of the descending aorta due to hepatisation of the lung parenchyma, which remained under arterial pressure. To control the aneurysm, a decision was made to unclamp the ETT, connect it directly to cell saver suction for processing, and re-transfuse this blood via the CPB circuit. With a reduction in intraparenchymal pressure, a clamp site was identified distally. However, it was still impossible to obtain proximal control without causing significant cardiac compression. Thus, the patient was cooled to 18°, the heart allowed to fibrillate without venting and an additional arterial limb spliced into the circuit to facilitate left carotid cannulation. With upper and lower body outflow cannula, dissection was completed, and the aneurysm was fully controlled.

A 22 mm interposition graft with a side arm was then sutured in place. Once the proximal anastomosis was complete, the carotid cannula was shifted to the side arm before resuming flow, rewarming the patient and performing the distal anastomosis. At 24°, sinus rhythm returned without ST changes. Due to difficult exposure, the aneurysm sac could not be entirely resected. The communication to the left bronchus was simply oversewn. The femoral artery was de-cannulated to avoid limb ischemia and support converted to extracorporeal membrane oxygenation (ECMO) to allow for lung rehabilitation. Haemostasis was eventually obtained after 4 h, allowing the thoracotomy to be temporarily closed, with the arterial ECMO cannula exiting through the 7^th intercostal space.

On day 2, the patient underwent chest re-exploration and washout, and bilateral lung ventilation resumed without obvious leak. On day 7, she was de-cannulated, and her thoracotomy was fully closed. On day 9, she developed a transiently blown left pupil, but head CT remained normal. A follow-up MRI showed subtle features of early Wallerian degeneration in the cerebral peduncles, but no features of a global hypoxic injury. On day 25, she was transferred to her home hospital extubated and neurologically intact, although with ongoing critical illness polyneuropathy necessitating rehabilitation.

Discussion

We present a case of intrabronchial aortic aneurysm rupture after intubation. This represents an extremely rare and catastrophic complication. Nevertheless, the preparedness of our team with everyone present in the room at the start of the case, rapid identification of the issue, and collaborative problem-solving were key to the patient’s survival.

The innovative use of the endotracheal tube as an access point for cell saver suctioning represents an extreme salvage technique. However, it was essential to mitigate ongoing blood loss and maintain CPB flows. This approach also proved lifesaving by reducing lung parenchymal pressure, facilitating surgical exposure, and limiting our use of blood products (Table 1).

Although maintaining upper and lower body perfusion isn’t compulsory at 18°, it was the best option here considering the 23-min hypoxic time pre bypass. Furthermore, the case was technically challenging and could lead to longer aortic cross-clamp times than usual. Protecting the brain at all costs seemed necessary and worth the risk of carotid cannulation. The patient’s survival and intact cognitive function postoperatively reflect the success of aggressive resuscitation and cerebral protection strategies.

Offering veno-arterial ECMO support using the side arm of the descending aortic graft brought through the thoracotomy incision and the femoral vein was quite creative. This allowed us to reduce the risk of lower limb ischemia. Ultimately, the 2 chest washouts and opportunities to visualize the lungs helped chest rehabilitation.

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Table 1.

Intraoperative transfusion requirements.

Blood product	Number of units	Volume (ml)
Packed red blood cells	23	5980
Cryoprecipitate	11	290
Fresh frozen plasma	13	3640
Platelets	2	526
Cell saver return	N/A	2560
Tranexamic acid	N/A	6245 (mg)
Prothrombin complex concentrate	N/A	1500 (IU)

Conclusion

Intrabronchial aortic aneurysm rupture represents a rare and catastrophic complication, which is best addressed with interdisciplinary collaboration and a flexible operative plan. Such cases require willingness to employ novel techniques when conventional approaches are insufficient, even in seemingly un-survivable scenarios.