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Evidence Base

Evidence Base

Oesophageal Doppler Monitoring (ODM) has gained support from a number of clinical and regulatory bodies, both within the UK and Internationally, due to the robust evidence available, demonstrating reduced post-operative complications and hospital length of stay;

Evidence Table


Enhanced Recovery Recommendations



NHS Standard Contract




Meta-analysis of IOFM Outcome Benefit

This meta-analysis has been prepared rigorously and objectively by Deltex Medical’s lead scientist. It is designed to be a valuable resource to everyone interested in the evidence for Intraoperative Fluid Management (IOFM) and may be downloaded and used without any need for permission.

Click here to download the full Meta-analysis

This meta-analysis of published outcome evidence of IOFM using a Stroke Volume Optimisation (‘SVO’) strategy confirms that ODM is the only technology that can reduce both the incidence of complications and the length of hospital stay during surgery.

Studies of ODM-guided SVO for IOFM demonstrate a reduction in the incidence of postoperative complications, whereas studies using an arterial pressure based device (PPWA) to guide SVO for IOFM did not:

Comp 11.12

ODM-guided IOFM demonstrated a 1.1-day reduction in length of hospital stay, an outcome not obtained with PPWA technologies.

Deltex Medical plans to update the meta-analysis as it becomes aware of further studies newly published in peer reviewed journals to create a ‘living’ up to date meta-analysis.

LOS 11.12

Visitors to this page are invited to contact the author by email, should you wish to highlight any new or published studies which may merit inclusion:

There is a large body of evidence to support the use of Deltex Medical’s technology. This includes a NICE recommendation, Randomised Controlled Trials (RCTs), published Audit studies, Reviews and Meta-analyses, Health Technology Assessments, and Case Histories. Click here for a pdf version of the Deltex Medical Bibliography.

Clinical Evidence

For any enquiries or requests regarding clinical papers on ODM or IOFM, please email


A number of Randomised Controlled Trials (RCTs) have been conducted using the ODM to guide fluid management during surgery. See below for a summary of each, or the Bibliography for a list of references.

St Thomas’ RCT, July 2016


Spanish RCT, May 2016

  • 72% reduction in total number of complications from 198 to 56 (p<0.01)
  • 45% reduction in number of patients suffering one or more complications, meaning Doppler use saved 28 additional patients from suffering any complication (15% v 28%: p<0.01)
  • 2 day reduction in median length of stay (p<0.01)

Results from a 450 patient Spanish Government funded multi-centre RCT were presented at Euroanaesthesia 2016. Patients undergoing major gastrointestinal, urological, gynaecological and orthopaedic surgery were managed using oesophageal Doppler to maintain an optimal Stroke Volume (SV), Mean Arterial Pressure (MAP) >70mmHg and Cardiac Index (CI) ≥2.5l/min/m2, when compared to conventional care.


This is the largest ever intra-operative fluid management RCT and the 12th RCT to show substantial improvements in patient outcomes from use of the 10% Stroke Volume Optimization algorithm guided by oesophageal Doppler.


ODM has since been recommended as the preferred monitor for use within the Spanish National Enhanced Recovery guidelines.


The authors concluded:

Fluid management using ODM guided SV, CI and MAP as “the key parameters, leads to a decrease in postoperative complications in patients undergoing major surgery”.

Oesophageal Doppler Monitoring has gained support from a number of clinical and regulatory bodies, both within the UK and internationally. Robust evidence demonstrates reduced post-operative complications and hospital length of stay.

March 2011 saw the publication of the NICE Medical Technology Guidance for CardioQ-ODM Oesophageal Doppler Monitor (MTG3). The recommendation is specifically for the use of the CardioQ-ODM Oesophageal Doppler Monitor to guide fluid optimisation during surgery in over 800,000 procedures in England annually. The CardioQ-ODM is the only technology with sufficient evidence-base to support such extensive recommendation and guidance. Read More

The British Consensus Guidelines on Intravenous Therapy for Adult Surgery (GIFTASUP) were released in 2008, for dissemination to members of participating professional bodies. GIFTASUP states that a response in SV should be assessed using flow-based technology, intraoperative treatment can reduce complication rates and length of hospital stay and that postoperative monitoring should be carried out in non-elective abdominal and orthopaedic surgery. Read More

The NHS Technology Adoption Centre (NTAC) conducted an audit in over 1300 patients, undergoing a range of surgical procedures in three NHS hospitals. Following the comprehensive evidence from the RCTs, NTAC wanted to determine whether clinicians could be trained to use ODM in ‘real world’ hospital settings and gain the same benefits observed in the tightly controlled clinical studies. Read More

The Société Francais d’Anesthésie et de Réanimation (SFAR) have recently released a set of guidelines entitled ‘Stratégie du remplissage vasculaire périopératoire’ (Guidelines for perioperative haemodynamic optimisation), which are SFAR Board approved. The objective is to ‘highlight perioperative vascular filling practices (VF) as a benefit for patients, for use in daily practice’. The first three recommendations relate directly to ODM and Fluid Management and received the highest possible rating of GRADE1+. Read More


The Introduction of Intraoperative Fluid Management to the NHS Standard Contract

NHS England remains firmly committed to the continuation of a full implementation of the recommendations set out in Innovation, Health and Wealth: Accelerating Adoption and Diffusion in the NHS. As part of this, providers should “demonstrate to commissioners that “trajectories for the intra-operative fluid management (IOFM) technologies are in place, which are consistent with National Technology Adoption Centre (NTAC)”.  

As part of the NHS Standard Contract’s Updated Technical Guidance, “Each provider which has not yet completed implementation of the high-impact innovations set out in Innovation, Health and Wealth, Accelerating Adoption and Diffusion in the NHS must agree within an SDIP action that it will take during 2014/15 to complete full implementation of all the innovations relevant to its services”

The OPCS-4 classification has recently been updated, to accurately reflect current NHS clinical practice. The use of Intraoperative Fluid Management (IOFM) in the NHS has increased significantly in the last five years and is predicted to continue to do so.

Y73.6  Intraoperative Fluid Monitoring

NHS England has commissioned NICE to take over the work of the NHS Technology Adoption Centre (NTAC). NICE Guidance (MTG3) on the CardioQ-ODM states “ODM should be considered for use in patients undergoing major or high risk surgery or other surgical patients in whom a clinician would consider using invasive cardiovascular monitoring”. The NICE recommendation states substantial available cost-savings of £1,100 per patient and recommends the CardioQ-ODM Oesophageal Doppler Monitor to guide fluid optimisation during surgery in over 800,000 surgical procedures in England annually.

Kent, Surrey & Sussex Academic Health Science Network commissioned The Cedar Report on IOFM. The report describes ‘the technologies currently available to the NHS, and indicated for IOFM, and summarises the evidence from published randomised trials (RCTs) for their efficacy regarding changes in hospital length of stay and post-operative complications, compared to standard care.’ The report demonstrates the large volume of clinical evidence available for ODM. Cedar produced this document as part of a contract with NICE for evidence preparation and assessment services.

Ensure that all procedures using IOFM are properly coded, using OPCS4 code: Y73.6, to demonstrate compliance with your local Service Development and Improvement Plan (SDIP).


  1. NHS Standard Contract 2014/15 – Updated Technical Guidance, NHS England, 24/02/2014 NHS Standard Contract
  2. Summary of Changes OPCS-4.6 – OPCS-4.7, Clinical Classifications Service, 07/11/2013 OPCS 4.6 – 4.7