The performance of EDM has been validated both through independently conducted, randomized controlled trials and through audited implementations into routine practice. Based on this evidence, EDM has been recommended by government entities, health payers and technology assessment bodies.
Esophageal Doppler Monitoring (EDM) has gained support from a number of clinical and regulatory bodies, both within the US and internationally, due to the robust evidence available; demonstrating reduced post-operative complications and hospital length of stay.
The Centers for Medicare and Medicaid Services (CMS) provides coverage for Esophageal Doppler Monitoring (EDM) under section 220.5 of the National Coverage Determination (NCD) Ultrasound Diagnostic Procedures. CMS determined that EDM is “reasonable and necessary” for all Medicare beneficiaries who meet the criteria for the following patient populations:
- Monitoring of cardiac output (Esophageal Doppler) for ventilated patients in the ICU; and
- Major surgery with an anticipate blood loss of greater than 500mls.
CMS’s decision was based in part on a technology assessment from the Agency for Healthcare Research and Quality (AHRQ) that concluded that in “patients undergoing surgical procedures with an expected substantial blood loss or fluid compartment shifts requiring fluid replacement” the clinical evidence for the use of EDM in the above patient populations was strong.
As part of their review of esophageal Doppler guided fluid management, CMS commissioned a technology assessment from the Agency for Healthcare Research and Quality (AHRQ). The technology assessment, published in March 2007, reviewed some 317 articles, including seven independently conducted, randomized controlled trials.
The technology assessment process grades the quality of evidence for a given technology as being ‘strong’, ‘moderate’, ‘weak’ or ‘inconclusive’. Strong evidence is defined as “evidence supporting the qualitative conclusion is convincing. It is highly unlikely that new evidence will lead to a change in this conclusion”.
The technology assessment for EDM concluded that in “patients undergoing surgical procedures with an expected substantial blood loss or fluid compartment shifts requiring fluid replacement” the clinical evidence for EDM was strong in respect of the following three statements:
- “Doppler-guided fluid replacement during surgery leads to a clinically significant reduction in major complications”;
- “Doppler-guided fluid replacement during surgery leads to a clinically significant reduction in the total number of complications”; and
- “Doppler-monitored fluid replacement leads to a reduction in hospital stay”.
As a UK company, we are proud that Deltex Medical was awarded a NICE recommendation for the CardioQ-EDM. The UK National Institute for Health and Care Excellence (NICE) published guidance on CardioQ-EDM in 2011 that considered extensive clinical and economic evidence. The guidance showed that EDM guided fluid management can reduce postoperative complications and reduce the length and costs of hospital stays. This recommendation was exclusively for the use of the EDM to guide fluid optimization during surgery.
NICE recommended that “CardioQ-EDM should be considered for use in patients undergoing major or high-risk surgery or other surgical patients for whom a clinician would consider using invasive cardiovascular monitoring” and concluded that “the case for adopting CardioQ-EDM in the NHS,…is supported by the evidence.” As a result of reducing complications and length of stay, NICE estimated savings of £1,100 ($1,750) per patient.
NICE states that ‘The “Case for Adoption” is based on the claimed advantages for introducing the specific technology compared with the current management of the condition… the technology has been found to offer advantages to patients and the NHS’. The evidence based used to form the conclusion of the NICE guidelines was based on randomized controlled trials in surgical procedures including: colorectal, cardiac and orthopedics.
The CardioQ-EDM is the only technology with a sufficient evidence base to support such extensive recommendation and guidance.
- 1.1 The case for adopting the CardioQ-ODM in the NHS, when used as described in 1.2, is supported by the evidence. There is a reduction in post-operative complications, use of central venous catheters and in-hospital stay (with no increase in the rate of re-admission or repeat surgery) compared with conventional clinical assessment with or without invasive cardiovascular monitoring. The cost saving per patient, when the CardioQ-ODM is used instead of a central venous catheter in the peri-operative period, is about £1100 based on a 7.5-day hospital stay.
- 1.2 The CardioQ-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.
- 3.1 Clinical outcomes relevant to the use of the CardioQ-ODM are mortality, peri-operative complications, reductions in the use of central venous catheters, length of critical care and in-hospital stay and re-admission rates. Full details of all clinical outcomes considered by the Committee are available in the assessment report at https://guidance.nice.org.uk/MT/80
- 6.1 The Committee concluded that the available data support a clinical benefit and a cost saving when the CardioQ-ODM is used in patients undergoing major or high-risk surgery or other surgical patients in whom a clinician would consider using invasive cardiac monitoring.
Innovation Health & Wealth
EDM guided fluid management is one of six High Impact Innovations listed in Innovation Health & Wealth, based on comprehensive evidence, proving that EDM guided fluid management can reduce postoperative complications and reduce length of hospital stay.
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 EDM and Fluid Management and received the highest possible rating of GRADE1+.
The guidelines state that during ‘high-risk surgery it is recommended to guide this filling, following the response obtained from the patient’s heart during surgery, in a continuous measurement’.
The guidelines are divided into 15 recommendations regarding fluid management. The first three recommendations are directly relevant to the use of EDM and Fluid Management.
Each recommendation made within the document is graded in a binary system:
High: You must do or not do (GRADE1+ or GRADE1-)
Low: It is possible to do or not do (GRADE2+ or GRADE2-)
All three recommendations relating directly to ODM fluid management received a GRADE1+ rating. This means that they must all be carried out in the case of high-risk patients, as the evidence level is high. It has been assessed by the SFAR that future evidence is unlikely to change any conclusions drawn from current evidence.
Q1: Filling guided by the measurement of the systolic ejection volume of (SV) reduces post-operative morbidity and duration of stay.
A1: Fluid titration for high-risk surgical patients should be guided by stroke volume to reduce post-operative morbidity, get earlier return to oral feeding and reduce length of stay. GRADE1+
High-risk surgical patients have an increased risk of post-operative complications due to the patient’s condition and/or the surgical procedure being carried out. Various evidence is supplied to support the grading of this recommendation, based primarily on the EDM evidence base. SFAR make the vital point that an increase in the Stroke Volume in response to filling confirms that guiding and managing SV was reevant and should be continued. SFAR also state that fluid challenges should be in volumes of 200ml ±50ml.
Q2: Should we interrupt the filling in the absence of the SV increase?
A2: It is recommended to discontinue filling if SV does not increase. GRADE1+
The recommendation is describing the requirement of the clinician to prevent overfilling, which can be just as concerning as the underfilling of a patient.
Q3: Should we regularly reassess the SV?
A3: Reassess SV regularly and the SV response to a fluid challenge, especially during periods of haemodynamic instability. GRADE1+
This recommendation is largely based on studies involving fluid monitoring by ODM. Within the appendix, there is an algorithm which is very similar to that of the ODM 10% fluid management algorithm. It does state that, in order to improve the prognosis of the patient, the method of fluid challenges and monitoring the SV response is beneficial when compared to the traditional method of fluid administration, which can sometimes lead to insufficient or excessive fluid volumes.
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.
The NTAC results clearly showed that Doppler-guided fluid management was able to:
- Reduce post-operative stay by 3.5 days
- Reduce Level 3 ICU stay by 5 days
- Reduce central venous catheter use by 23%
- Reduce readmission rates by 29%
- Reduce reoperations by 30%.
Following these findings, EDM has since been adopted as a standard of care in these hospitals.
See the ‘How to why to’ Guide for more information.
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.
The guidelines were developed on behalf of BAPEN Medical, the Association for Clinical Biochemistry, the Association of Surgeons of Great Britain and Ireland, the Society of Academic and Research Surgery, the Renal Association and the Intensive Care Society. A total of 28 recommendations were made. Three recommendations relate directly to individualized fluid management, monitored using the flow-based parameters of the CardioQ-EDM monitor.
Each recommendation has been given an evidence level grade from 1-5, in accordance with the Oxford Centre for Evidence-Based Medicine, levels of evidence. A score of 1A represents the highest possible level of supporting clinical evidence.
Recommendation 12: When the diagnosis of hypovolaemia is in doubt and the central venous pressure is not raised, the response to a bolus infusion of 200 ml of a suitable colloid or crystalloid should be tested. The response should be assessed using the patient’s cardiac output and stroke volume measured by flow-based technology if available. Alternatively, the clinical response may be monitored by measurement/estimation of the pulse, capillary refill, CVP and blood pressure before and 15 minutes after receiving the infusion. This procedure should be repeated until there is no further increase in stroke volume and improvement in the clinical parameters.
Evidence Level 1B – Flow-Based Measurements
Recommendation 13: In patients undergoing some forms of orthopaedic and abdominal surgery, intraoperative treatment with intravenous fluid to achieve an optimal value of stroke volume should be used where possible as this may reduce postoperative complication rates and duration of hospital stay.
Evidence Level 1A – Abdominal Surgery
Evidence Level 1B – Orthopaedic Surgery
Recommendation 14: Patients undergoing non-elective major abdominal or orthopaedic surgery should receive intravenous fluid to achieve an optimal value of stroke volume during and for the first eight hours after surgery. This may be supplemented by a low dose of dopexamine infusion.
Evidence Level 1B