This study aimed to investigate the effects of an incorrectly positioned tracheostomy tube on flow resistance. A laboratory-based model of the trachea was used with both cuffed and uncuffed tracheostomy tubes inserted to variable depths. With a constant metered flow through the model, the pressure for given depths of insertion was recorded. The model was then re-run to test the effect of different flow rates on the system. A total of 468 individual results were grouped and statistically analysed. They showed that both over-and under-insertion increase the pressure within the circuit and that a cuffed tracheostomy tube offers a degree of protection against this. These results were statistically significant with P < 0.05 demonstrating that incorrect positioning has a greater resistance to flow. These results provide an essential scientific basis for further work to assess the clinical significance of incorrect positioning as well as suggesting the need to monitor tube position.

Simple liver cysts are common, rarely causing significant morbidity or mortality. Budd–Chiari syndrome (BCS) is caused by obstruction of hepatic venous outflow and is the leading cause of postsinusoidal liver failure. We present a rare case of BCS caused by a simple hepatic cyst.A 16cm × 16cm liver cyst was found on computed tomography of a 66-year-old woman presenting with abdominal pain. The cyst had become infected, thus enlarged, exerting mass effect with almost complete compression of the inferior vena cava. Shortly after admission, the patient developed acute liver failure, with deranged clotting and hepatic encephalopathy requiring full organ support on the intensive care unit. Cardiac output studies showed a low cardiac index of 1.4l/min/m2.An emergency laparotomy with fenestration of the cyst and drainage of 2l of purulent material led to a full recovery. Intraoperative cystic fluid aspirates later confirmed no evidence of Echinococcus. Histology confirmed a simple cyst. Liver biopsies showed severe, confluent, bridging necrosis, without background parenchymal liver disease.Acute BCS due to rapid compression of all major hepatic veins leading to fulminant hepatic failure is rare. Our case highlights a clinically significant complication of a simple liver cyst of which clinicians should be aware when managing these ‘innocent’ lesions.

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