S131 Novel model of indwelling pleural catheter in mice with malignant pleural effusion

Introduction Malignant pleural effusion (MPE) is common and indicates advanced malignancy. Indwelling pleural catheters (IPC) are used in recurrent MPE. To date, there has not yet been a reliable mouse model of MPE utilising IPC, and such model would be useful especially since intrapleural therapy for malignancy is a burgeoning area of research, and IPC provides direct access to the pleural space with the potential of testing novel treatment agents. Aim To design the first experimental mouse model with IPC. Method 250,000 Lewis lung carcinoma (LLC) cells were injected into the pleural space of anaesthetised C57BL/6 mice. 7–9 days are required for development of MPE from time of LLC intrapleural injection,1 so on day 7, the IPCs were inserted: 3 punctures were made at distal end of a polyurethane tube (PU-40) to enhance catheter flow; a small puncture was made through the 7th rib space in mid-axillary line of the mice. PU-40 was advanced 1.5 cm into the pleural space. A 16G needle was used to puncture the dorsum between scapulae, and advanced through subcutaneous tissue towards catheter insertion site. Proximal end of PU-40 tube was then passed through needle and out between the scapulae, leaving IPC tunnelled through the subcutaneous space. MPE was drained while mice were still under anaesthesia. Results Mean volume of fluid drained (n=19) was 188 ul (range 0–770 uL). Post-mortem dissection demonstrated bulky tumour with minimal residual MPE (n=17). Occasionally, IPC was enveloped by tumour, blocking MPE drainage, with resulting residual MPE within pleural space (n=2). IPC was also useful to allow intrapleural drug delivery. Potential agents could be injected through IPC using a 22G syringe by means of a syringe accessible port. A typical volume of 100 uL phosphate buffer solution was well tolerated by mice. Discussion This novel mouse model seeks to mimic MPE drainage using an IPC in humans, and allows MPE aspiration as well as drug delivery to the pleural space. This model will enable the testing of the use and effectiveness of intrapleural therapies in the treatment of MPE. Reference Stathopoulos GT, et al. AJRCMB2006;34(2):142–50.