s / International Journal of Surgery 9 (2011) 495–546 525 ABSTRACTS 0316 IS IT COST EFFECTIVE TO INTRODUCE INTRA-OPERATIVE MOLECULAR ANALYSIS OF SENTINEL LYMPH NODES USING ONE STEP NUCLEIC ACID AMPLIFICATION (OSNA)? Amber Holmes, Ross Elledge, Michelle Mullan, Rachel Bright-Thomas, Steven Thrush. Worcestershire Acute Hospitals Trust, Worcester, UK Introduction: Axillary ultrasound is reported as having a sensitivity of 6072.7% in detecting metastatic lymph nodes, while intra-operative molecular analysis with OSNA has a reported sensitivity of 91.7-100%. The purpose of this audit was to assess the sensitivity of ultrasound within our unit, thereby ascertaining cost effectiveness of introducing OSNA. Methods: Patient records were audited retrospectively for all breast cancer patients who underwent axillary lymph node dissection (ALND) between December 2009 and November 2010 inclusive. Results: A total of 184 sentinel lymph node biopsies (SLNB) and 75 ALNDs were carried out during the audit period. Eighty-four per cent (n1⁄463) of patients who underwent ALND had an ultrasound scan prior to surgery. Ultrasound demonstrated a sensitivity of 41%, resulting in a return to theatre for a completion axillary lymph node dissection (CALND) in 39 patients, incurring estimated additional costs of between £69,303 and £100,386 and inpatient occupancy of between 62.01 and 140.4 inpatientdays. Conclusions: The sensitivity of axillary ultrasound was poorer than in the literature. OSNA has been calculated to cost an additional £300 per procedure, meaning additional costs of £55,200 for our department. This would represent potential gains of up to £45,186, rendering the introduction of OSNA highly cost effective. 0321 THE IMPACT AND APPROPRIATENESS OF PATIENT PLACEMENT IN ACUTE SURGICAL ADMISSIONS – A CLINICAL AUDIT Eleanor King, Adam Peckham-Cooper. Leeds General Infirmary, Leeds, West