3 Clinical evidence

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.

Patients undergoing surgery

3.2 Wakeling et al. (2005) reported a trial of 124 patients undergoing bowel surgery,which found that the median hospital stay after surgery was 10 days when the CardioQ-ODM was combined with central venous pressure monitoring compared with 11.5 days in the control group who had central venous pressure monitoring alone (p = 0.031). The median difference in time to fitness for discharge was 1.5 days in favour of the CardioQ-ODM (p = 0.012). Noblett et al. (2006) reported a study of 108 patients undergoing bowel surgery and found the median post-operative stay was 7 days when the CardioQ-ODM was combined with central venous pressure monitoring compared with 9 days in the control group who had central venous pressure monitoring alone (p = 0.003). The median time to fitness for discharge was 6 days for the CardioQ-ODM monitoring compared with 9 days for the control group (p = 0.003).

3.3 Mythen et al. (1995) reported a trial of 60 patients undergoing cardiac surgery,which found that the mean length of hospital stay was 6.4 days when the CardioQ-ODM was combined with central venous pressure monitoring compared with 10.1 days in the control group who had central venous pressure monitoring alone (p = 0.011). The mean length of stay in the critical care unit was also reduced by 0.7 days (1 day versus 1.7 days, p = 0.023).

3.4 Gan et al. (2002) reported a trial of 100 patients undergoing general, gynaecological or urological surgery, which found the median hospital stay was 6 days when the CardioQ-ODM was combined with central venous pressure monitoring compared with 7 days in the group with central venous pressure monitoring alone (p = 0.03). The difference in mean length of hospital stay was 2 days.

3.5 Venn et al. (2002) reported a three-arm trial of 90 patients undergoing surgery for fractured neck of femur, which compared CardioQ-ODM monitoring with central venous pressure monitoring and with conventional assessment. The mean time to fitness for discharge was 7.7 days (95% confidence interval [CI] 5.9 to 12.3 days) in the CardioQ-ODM group, 10 days (95% CI 8.1 to 12.0 days) in the central venous pressure group, and 13.9 days (95% CI 11.9 to 16.9 days) in the conventional assessment group (p = 0.035). The mean length of hospital stay was 13.5 days (95% CI 10.9 to 17.5 days) in the CardioQ-ODM group, 13.3 days (95% CI 10.3 to 19.2 days) in the central venous pressure group and 17.5 days (95% CI 13.9 to 24.4 days) in the conventional assessment group (p = 0.27). Sinclair et al. (1997) reported a study of 40 older adults undergoing surgery for fractured neck of femur, which found that mean acute hospital bed stay was 10 days in the group who had CardioQ-ODM monitoring compared with 17 days in a group who had conventional assessment (p < 0.05). A 6-day reduction in mean time to fitness for discharge (9 days versus 15 days, p < 0.05) and a 9-day reduction in mean length of hospital stay (11 days versus 20 days, p < 0.05) were also reported.

3.6 Senagore et al. (2009) reported a three-arm trial in which CardioQ-ODM monitoring with colloid fluid administration and CardioQ-ODM monitoring with crystalloid fluid administration were compared with standard fluid management in patients undergoing laparoscopic bowel surgery. The length of hospital stay was shortest with standard fluid management: 64.9 hours (21 patients) compared with 75.5 hours for CardioQ-ODM-guided colloid fluid management (22 patients) and 71.8 hours for CardioQ-ODM-guided crystalloid fluid management (21 patients, p < 0.05). The difference in hospital stay was small and the paper did not report whether hospital stay was a mean or median value. This trial included patients having lower risk surgery and used an atypical CardioQ-ODM-guided protocol for fluid management. The External Assessment Centre considered this study and concluded that, because of the differences in design, these results have little effect on the body of evidence, which largely supports monitoring with CardioQ-ODM compared with standard fluid management.

3.7 Wakeling et al. (2005) reported a study of 124 patients undergoing bowel surgery and found total complications were reduced in the group who had CardioQ-ODM monitoring combined with central venous pressure monitoring compared with the group who had central venous pressure monitoring alone (38% [24/67] versus 59% [38/67], p = 0.013). Gastrointestinal complications were also reduced in the group who had CardioQ-ODM monitoring (14% [9/67] versus 45% [29/67], p = 0.001). Other indicators of enhanced recovery from surgery favoured CardioQ-ODM monitoring over central venous pressure monitoring alone, namely the return of flatus (median 3 days versus 4 days, p = 0.085), bowel movement (median 4 days versus 5 days, p = 0.014) and the adoption of a full diet (median 6 days versus 7 days, p = 0.001). Noblett et al.(2006) reported a study of 108 patients undergoing bowel surgery, which found that intermediate or major complications were lower in a group who had CardioQ-ODM monitoring and central venous pressure monitoring compared with a group who had central venous pressure monitoring alone (2% [1/54] versus 15% [8/54], p = 0.043). Patients who had CardioQ-ODM monitoring tolerated food sooner (median 2 days versus 4 days, p value not provided), but there was no difference in the return of flatus (median 2 days versus 2 days, p = 0.9) or bowel movement (median 3 days versus 4 days, p = 0.7).

3.8 Mythen et al. (1995) reported a study of 60 patients undergoing cardiac surgery, which found that gut hypoperfusion at the end of surgery and major complications after surgery were lower with the CardioQ-ODM and central venous pressure monitoring than with central venous pressure monitoring alone (gut hypoperfusion: 7% [2/30] versus 56% [17/30], p < 0.001; major complications: 0% [0/30] versus 20% [6/30], p = 0.01).

3.9 Gan et al. (2002) reported a study of 100 patients undergoing general, urological or gynaecological surgery, which found that 7 patients needed antiemetic drugs after surgery when CardioQ-ODM monitoring was combined with central venous pressure monitoring compared with 18 patients who had central venous pressure monitoring alone (p < 0.05).

3.10 The NHS Technology Adoption Centre reported audit data following the adoption of intra-operative oesophageal doppler-guided fluid management in three hospitals in England. CardioQ-ODM was used for intra-operative oesophageal doppler-guided fluid management in a total of 626 patients undergoing major intra-abdominal or orthopaedic surgery. Results from these patients were compared with an historical control group of 621 patients who received standard care. The results confirmed the potential benefit of oesophageal doppler monitoring, with reduction in mean length of hospital stay of 3 days, reduction in hospital stay after surgery of 4 days, and 23% fewer surgical patients requiring a central venous catheter to be inserted.

3.11 Evidence from a number of systematic reviews of oesophageal doppler monitoring was also considered. The most recent major review was a Health Technology Assessment performed by the UK National Institute for Health Research. The Health Technology Assessment considered ten clinical trials that included a total of 959 patients. Eight of these trials used the CardioQ-ODM (accounting for 77% of the total number of patients), whereas the other two studies used other oesophageal doppler monitoring devices. Furthermore, eight of these studies were of patients undergoing surgery whereas two investigated the impact of oesophageal doppler monitoring on patients in a critical care setting. The review reported that generic oesophageal doppler monitoring reduced the length of stay by on average 2 days, and by up to 6 days. The review also reported that complications were reduced by more than 50% when oesophageal doppler monitoring was used either during surgery or after surgery in the critical care unit. In a subgroup analysis that assumed that central venous pressure monitoring was used in both study arms, the odds ratio of complications was 0.43 for oesophageal doppler monitoring during surgery and 0.49 for oesophageal doppler monitoring after surgery in the critical care unit.

Patients in the critical care unit

3.12 McKendry et al. (2004) reported a study of 174 patients in a critical care unit after cardiac surgery, which found no statistically significant difference in mean hospital stay between patients who had CardioQ-ODM monitoring combined with central venous pressure monitoring and patients who had central venous pressure monitoring alone; although the median hospital stay was reduced to 7 days in the group who had CardioQ-ODM monitoring compared with 9 days in the group with central venous pressure monitoring alone (p = 0.02).

Committee considerations

3.13 The Committee considered that the available evidence supported a reduction in peri-operative complications and length of in-hospital stay in patients undergoing surgery when the CardioQ-ODM was used compared to outcomes for patients with central venous pressure monitoring alone. It observed that these benefits were achieved without an increase in rates of repeat surgery or re-admission.

3.14 The Committee concluded that patients most likely to benefit from the use of the CardioQ-ODM are those in whom the clinician would consider using invasive cardiovascular monitoring (such as central venous pressure or pulmonary artery catheter monitoring). This will include patients undergoing major or high-risk surgery or high-risk patients undergoing intermediate-risk surgery.

3.15 The Committee noted that although evidence of benefit with the CardioQ-ODM was particularly convincing for patients undergoing gastrointestinal surgery, benefit was also observed in patients undergoing other types of surgery.

3.16 The Committee was advised that the CardioQ-ODM cannot usually be used in patients undergoing head and neck, oesophageal or aortic surgery and is poorly tolerated by conscious patients after surgery.

3.17 The Committee received expert advice that the CardioQ-ODM may sometimes be used with, rather than as an alternative to, central venous pressure monitoring in patients undergoing surgery. It noted that this is most likely to be the case when clinicians are gaining experience with the new technology. Central venous catheters will still be needed in some cases for central venous access and for administering inotropic drugs.

3.18 The Committee recognised that monitoring cardiac output is helpful in a critical care environment. However, it concluded that there is insufficient evidence to recommend CardioQ-ODM monitoring in preference to other techniques for monitoring cardiac output in critical care.

3.19 The Committee considered that further research would be helpful to compare the CardioQ-ODM with other techniques for monitoring cardiac output, particularly in patients in the critical care environment.

3.20 The Committee recognised that trials using the CardioQ-ODM are currently ongoing in the UK and internationally. The Committee was advised on the relevance and impact of ongoing and recently published trials (such as the OPTIMISE trial and the COMPETE C study) and concluded that the available evidence supported the benefits of CardioQ-ODM.

3.21 The Committee considered that there is no evidence of adverse events which suggests that the use of the CardioQ-ODM is harmful to patients.

  • National Institute for Health and Care Excellence (NICE)