Table 2. Estimated cost of adverse events (1999 values) Specialty No of patients with adverse events Mean (SD) extra bed days for all adverse events Daily cost of bed (£) Total cost of additional bed days for study sample (£1000s) General medicine 25 4.87 (5.67) 171 20.8 General surgery 47  6.07 (12.52) 282 80.4 Obstetrics 7 3.57 (2.88) 305 7.6 Orthopaedics 40 14.58 (17.87) 311 181.4 Total 119  8.54 (13.55)   290.2