(ShareCast News) - Investors were left unimpressed after Deltex Medical said its 2015 sales were pretty much flat on the year, with revenue in the UK on the slide.The company said sales for the year ended 31 December came in at £6.4m, down from £6.5m in 2014, as strong growth in the US and other export markets was offset by a 21% slump in UK probe revenue and a £0.3m drop in UK monitor revenues due to NHS funding issues.Deltex, which makes oesophageal Doppler monitoring technology, said US probe revenues were up 31% to £1.3m thanks to the addition of 11 new platform accounts, while the number of probes sold in its international markets grew 41%.Total monitor revenues were down £0.5m and the company's cash position at the end of December was £0.6m.Also on Wednesday, Deltex said it has added a further new account to its platform programme in the US.The new hospital is the flagship hospital of a seven hospital system and is the third new platform programme account in the company's Great Lakes sales territory since it was established in the first quarter of last year.The addition brings the total number of US platform accounts to 18 and the company said it was on track to reach its target of 30 platform accounts by mid 2016.Chairman Nigel Keen said: "Deltex Medical enters 2016 with growing traction in the US and other export markets driving overall momentum and reducing its exposure to the challenging UK market."In addition to the returns we are beginning to see from our investment in the US market, we are expecting to see increasing returns over the next twelve months from investments we have made in product development and further operational improvements which start to roll-out in the first quarter of 2016."At 0955 GMT, Deltex shares were down 12% to 4.98p.