General anaesthesia vs. conscious sedation for transfemoral aortic valve implantation: a single UK centre before-and-after study.

Reported data suggest that 99% of transfemoral, transcatheter aortic valve implantations in the UK are performed under general anaesthesia. This before-and-after study is the first UK comparison of conscious sedation vs. general anaesthesia for this procedure. Patients who underwent general anaesthesia received tracheal intubation, positive pressure ventilation, radial arterial and central venous access and urinary catheterisation. Anaesthesia was maintained with propofol or sevoflurane. Patients who received conscious sedation had a fascia iliaca and ilioinguinal nerve block and low-dose remifentanil infusion, without invasive monitoring or urinary catheterisation. Recruitment took place between August 2012 and July 2015, with a 6-month crossover period between November 2013 and June 2014. A total of 88 patients were analysed, evenly divided between the two groups. Patients receiving conscious sedation had a shorter anaesthetic time (mean (SD) 121 (28) min vs. 145 (41) min; p < 0.001) and recovery room time (110 (50) min vs. 155 (48) min; p = 0.001), lower requirement for inotropes (4.6% vs 81.8%; OR (95% CI) 0.1 (0.002-0.050); p < 0.001) and a lower incidence of malignant dysrhythmia (0% vs 11.4%; p = 0.020). Conscious sedation appears a feasible alternative to general anaesthesia for this procedure and is associated with a reduced requirement for inotropic support and improved efficiency.

A technique for insertion of self-expanding tracheal and bronchial stents.

We describe the use of skin markers, placed under radiologic control, to identify the limits of airway strictures as a reliable technique for the accurate placement of self-expanding stents. The technique has been used successfully in 14 patients with extrinsic airway compression or bronchomalacia.

A new porcine model of reperfusion injury after lung transplantation.

Rodent models have been described to investigate lung preservation and reperfusion injury but have significant disadvantages. In large animals single lung transplant studies are probably optimal but problems remain over the ability to rigorously separate the lungs for assessment while promoting medium to long-term animal survival for meaningful investigation. Our aim was to develop a novel and refined large animal model to assess reperfusion injury in the transplanted lung, overcoming the difficulties associated with existing models. Specifically, small animal models of lung transplantation usually have short perfusion times (often one hour) and include extracorporeal circuits while larger animal models often require the contralateral lung to be excluded after transplantation-an unphysiological situation under which to evaluate the graft. A porcine model of left lung allotransplantation was developed in which native and donor lungs are individually ventilated. Sampling catheters placed within the graft lung allowed specimen withdrawal without mixing of blood from the contralateral lung after reimplantation. The model permits a variety of clinical scenarios to be simulated with the native lung supporting the animal irrespective of function in the graft. This model has been used in over 60 transplant procedures with a postoperative survival time of 12 h being readily achieved. The mean operating time was 2.6 h. The mortality rate is 4% in our series. We have found the model to be reliable, reproducible and flexible. We propose this model as an adaptable investigation for evaluating lung reperfusion injury and preservation.