Clearsight™ use for haemodynamic monitoring during the third trimester of pregnancy - a validation study.

BACKGROUND: We assessed the validity of Clearsight™ as a non-invasive cardiac output and stroke volume monitoring device, comparing it with transthoracic echocardiography measurements during the third trimester of pregnancy. METHODS: Measurements obtained from Clearsight™ were compared with those from echocardiography as the gold standard. The precision and accuracy of the Clearsight™ was measured using the Bland and Altman method. Clinical agreement with echocardiography was assessed using the agreement tolerability index. RESULTS: Measurements were recorded from 44 pregnant women with a median [IQR range] gestational age of 33 [30-37] weeks. We found that Clearsight™ measurements presented a systematic overestimation of cardiac output, with mean bias [CI 95%] of 2.7 [2.3-3.0] L/min, with limits of agreement of  -0.1 to 5.4 L/min. It overestimated stroke volume, with a bias of 29.5 [25.0-33.4] mL and a limit of agreement of -1.6 to 60.1 mL. In addition, the analysis of cardiac output showed a percentage of error of 41% and intra-class correlation [CI 95%] of 0.37 [0.17 to 0.53, P <0.001]. For stroke volume, the percentage of error was 40% and intra-class correlation 0.16 [-0.1 to 0.34; P=0.27]. We found that agreement tolerability index scores were unacceptable. We evaluated the ability of the device to track changes in cardiac output by inducing a left lateral decubitus position, but the analysis was inconclusive. CONCLUSION: The agreement between Clearsight™ and the echocardiography measurements of cardiac output and stroke volume were not within an acceptable range in the third trimester of pregnancy.

Can point-of-care ultrasound predict spinal hypotension during caesarean section? A prospective observational study.

Spinal anaesthesia for elective caesarean section is associated with maternal hypotension, secondary to alteration of sympathetic tone and hypovolemia, in up to 70% of cases. Measurement of the subaortic variation in the velocity time integral (VTI) after passive leg raising allows prediction of fluid responsiveness. Our objective, in this prospective single-centre observational study, was to assess the ability of change in VTI after 45° passive leg raising to predict hypotension after spinal anaesthesia. Ultrasound measurements were performed just before elective caesarean section. Anaesthesia, intravenous coloading and prophylactic vasopressor treatment were standardised according to current guidelines. We studied 40 women. Hypotension occurred in 17 (45%) women. The area (95%CI) under the receiver operating characteristics (ROC) curve for the prediction of spinal hypotension was 0.8 (0.6-0.9; p = 0.0001). Seventeen women had a change in VTI with leg elevation ≤ 8%, which was predictive for not developing hypotension, and 11 had a change ≥ 21%, predictive for hypotension. The grey zone between 8% and 21%, with inconclusive values, included 12 women. We suggest that cardiac ultrasound provides characterisation of the risk of hypotension following spinal anaesthesia at elective caesarean section, and therefore may allow individualised strategies for prevention and management.

Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost.

OBJECTIVE: To determine the effect of implementing a daily lung ultrasound round on the number of chest radiographs and chest computed tomography (CT) scans in a polyvalent intensive care unit (ICU). STUDY DESIGN: Retrospective study comparing two consecutive periods. PATIENTS: All patients hospitalized for longer than 48 hours in a polyvalent ICU. METHODS: Implementation of a daily lung ultrasound round after a short educational program. The number of chest radiographs and chest CT scans and the patient outcome were measured before (group PRE) and after (group POST) the implementation of a daily lung ultrasound round. RESULTS: No demographic difference was found between the two groups, with the exception of a higher severity score in the group POST. For each ICU stay, the number of chest radiographs was 10.3 ± 12.4 in the group PRE and 7.7 ± 10.3 in the group POST, respectively (P<0.005) The number of chest CT scans was not reduced in the group POST, as compared with the group PRE (0.5 ± 0.7 CT scan/patient/ICU stay versus 0.4 ± 0.6 CT scan/patient/ICU stay, P=0.01). The ICU mortality was similar in both groups (21% versus 22%, P=0.75) CONCLUSION: The implementation of a daily lung ultrasound round was associated with a reduction in radiation exposure and medical cost without altering patient outcome.