The Oesophageal Doppler Monitor (ODM+)


Measuring Central Blood Flow

The oesophageal Doppler monitor is designed to allow clinicians to assess cardiac function and guide fluid and drug administration during surgery and critical care. It is highly responsive in tracking changes in Stroke Volume and Cardiac Output during intervention using direct thoracic aortic blood velocity measurements. Only oesophageal Doppler has been shown to have the precision to drive the 10% Stroke Volume Optimisation algorithm widely acknowledged as the basis for Intraoperative Fluid Management (IOFM) and has shown benefit when used as part of an Enhanced Recovery After Surgery Programme.

Oesophageal Doppler monitoring is the only technology to measure blood flows in the central circulation; it is highly sensitive to changes in flow and measures them immediately and accurately. ODM+ is simple to use and enables hospital clinicians to precisely guide Intraoperative Fluid Management (IOFM) during surgery based on small changes in circulating blood volume and so avoid the dangers of reduced oxygen delivery.

The keys to the success of ODM+ in guiding IOFM are its ability to measure blood flow directly and its precision (low repeatability error) which allows it to recognise the small 10% changes in Stroke Volume which is the basis of published Stroke Volume Optimisation protocols.

Extensive clinical trials have demonstrated that with direct measurement of blood flow, clinicians can correct individual patient circulating blood volume. It has been reported that 70% of patients have hypovolaemia (low blood volume) when they are prepared for surgery. The hypovolaemia results from the combined effects of poor diet, dehydration, preoperative fasting, the vasodilatory effects of anaesthetic agents and blood loss during the surgical procedure

The Addition of Arterial Blood Pressure Analysis

​The ODM+ is the world’s first fluid management and cardiac output monitoring system to measure both flow and pressure directly. An exciting new upgrade to the proven Doppler technology, the monitor combines the proven ODM Doppler measurement of blood flow with Pulse Pressure Waveform Analysis (PPWA). This provides users with a proven, highly sensitive “Flow Monitoring Mode” to guide intervention and the simplest calibration of a “Pressure Monitoring Mode” for extended continuous monitoring yet devised. The ODM+ has a Pulse Pressure Waveform (PPWA) mode which is quickly and easily calibrated at any time and as often as required, from the Doppler signal and provides continuous monitoring.

Flow Monitoring Mode using the oesphageal Doppler probe.
Pressure Monitoring Mode using the arterial wave calibrated from the oesophageal Doppler cardiac output.










The PPWA algorithm can be recalibrated at any time, when there is known or suspected arterial compliance changes, from the Doppler waveform. Previous cardiac output monitors have either been ideal intervention devices, fast precise responsive flow based measurement but non-continuous or less responsive pressure based continuous monitors, requiring complex calibration and frequent recalibration to be effective.

Designed for intensive care and high risk surgical applications, the ODM+ brings together simple, minimally invasive oesophageal Doppler monitoring (ODM) flow based technology with a proven PPWA system. The ODM+ provides an unparalleled range of functional haemodynamic parameters. Patients can be continuously monitored for extended periods between intervention and calibration episodes.

​The brochure can be downloaded here.