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A 36 year old man presented to hospital with a Fisher grade 2 subarachnoid haemorrhage (SAH). He was shown to have an 8.5 × 12 mm right middle cerebral artery aneurysm which was clipped without complication.
Three days after craniotomy, he was alert with excellent gas exchange and was extubated. Three hours later he suddenly became cyanotic, profoundly hypoxic, and had a near respiratory arrest. He was immediately intubated and ventilated. He remained haemodynamically stable without the need for inotropic support; however, 100% oxygen and nitric oxide (20 ppm) was required to maintain the patient’s SaO2 over 90%. An urgent computed tomographic pulmonary angiogram (CTPA) showed the presence of a large “saddle embolus” extending into both left and right pulmonary arteries (panel A).
Thrombolysis was considered to be contraindicated because of his recent craniotomy, and as such he proceeded to have an open embolectomy via median sternotomy with cardiopulmonary bypass. Intraoperative transoesophageal echocardiogram revealed the presence of a patent foramen ovale (PFO) with torrential right to left shunt which accounted for his haemodynamic stability throughout. The presence of a PFO was also demonstrated on the CTPA when the images were reviewed postoperatively (panel B). During the 90 minute procedure a 25 cm intact embolus was removed from the main pulmonary trunk (panel C). Post-embolectomy and PFO closure the gaseous exchange improved dramatically, and the patient proceeded to make a satisfactory recovery.
This case demonstrates that haemodynamic instability may not be present in massive pulmonary embolism if there is a large right to left intracardiac shunt. It also demonstrates that surgical embolectomy is a viable option when thrombolysis is contraindicated, and can be safely performed three days after craniotomy.
We would like to thank Mike Das Gupta for his photograph of the pulmonary embolus.