|The CardioQ utilises descending aortic flow to provide an immediate assessment of left ventricular performance. The technology uses a thin latex-free silicone probe; about 6 mm in diameter with an internal spring coil to ensure flexibility and rigidity. The probe contains crystal which produces a continuous ultrasound wave of 4 MHz.
The lubricated oesophageal probe is inserted with the bevel of the tip facing up at the back of the patient's throat. The probe is inserted down to the 40 cm marker, rotated and slowly pulled back while listening to the audible signal. The ideal probe tip location is at the level between the fifth and sixth thoracic vertebrae because at that level the aorta is adjacent and parallel to the oesophagus.
This location is achieved by superficially landmarking the distance to the third sternocostal junction anteriorly. Because of the mild discomfort associated with placing the probe and maintaining it in a fixed position, patients require adequate sedation. Insertion of the oesophageal Doppler ultrasound probe has been described in the awake patient. This would extend the use of this device to include patients not heavily sedated or anaesthetised. The technique described involves using local anaesthetic to the nasal mucosa and posterior oropharynx and application of nasal vasoconstrictors.
Once inserted, the oesophageal probe is connected to the CardioQ monitoring system via a smart connector which stores patient data.
All of the probes are sleeved in a non-toxic latex free silicon rubber. The highly flexible nature of the probe allows it to be inserted through either the nose or mouth. The lateral stiffness created by the design of the probe, allows the probe to be positioned easily through rotating precisely without twisting the sleeve.
All of the probes are single use design, therefore any cross contamination risks associated with the cleaning of probes due to multiple use is removed.