Oesophageal Doppler monitoring: evidence and hip surgery

Abstract

We would like to thank the authors of the editorial published in December’s Anaesthesia [1] highlighting the quality of evidence used in the National Institute for Health and Clinical Excellence (NICE) guidance on oesophageal Doppler monitoring (ODM). While we recognise that minimally-invasive cardiac output monitoring has an important role in careful fluid management in high-risk surgical patients, we too question the singling out of one particular device over a number of commercially available products, considering the quality of evidence used to support its use. A bold statement suggesting a saving of approximately £1100 per patient based on hospital stay by using the CardioQ™ over conventional central venous catheterisation is another worrying point. Venn et al. [2] found that there was a difference in the time until medically fit between patients who had goal directed fluid replacement with ODM guidance compared with the control group. However, they went on to say that they could not show a significant reduction in total hospital stay as there are a number of socio-economical factors that need to be taken into consideration. Sinclair et al. [3] studied the effects of intra-operative fluid management guided by ODM in a small number of patients and found that it corresponded to a shorter hospital stay and therefore could be shown to be cost-efficient. However, Sinclair et al. failed to mention the time lapse between admission and surgery; the pre-operative medical intervention for each patient was not standardised; and the study was conducted in 1997 with the inpatient stay data compared with an in-house audit carried out in 1990-91. We applaud those who conducted this landmark study, but with the design limitations, it is a concern that so much weight was attached to it for the NICE guidance. Patients with fractured femurs are a difficult group to study and many have regional anaesthesia for their surgery. We have found that ODM is particularly difficult to use in awake patients and especially so in those with any cognitive impairment, which accounts for approximately one third of the hip fracture population. Further work is needed on alternative methods of monitoring in this high-risk group of patients.