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Title: The use of non-invasive cardiac output monitors in pregnancy to assess maternal haemodynamics in uncomplicated and pathological pregnancies
Author: Vinayagam, Dimuthu Chakinda
ISNI:       0000 0004 7972 1811
Awarding Body: St George's, University of London
Current Institution: St George's, University of London
Date of Award: 2018
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This thesis aims to examine the use of non-invasive cardiac output monitors pregnancy. The non-invasive monitors will be examined through the following objectives: 1. Assess the repeatability and reproducibility 2. Assess the accuracy and precision against a reference method 3. Assess the correlation, accuracy and precision between the non -invasive methodologies. The non-invasive monitors will be used to assess maternal haemodynamics through the following objectives: 1. Construct reference ranges, centiles and changes in haemodynamics throughout pregnancy 2. Examine the effect of maternal characteristics on haemodynamics 3. Investigate maternal haemodynamics in morbid obesity Methods USCOM® and NICOM® will be the non-invasive devices utilised during this research study. Statistical analysis includes correlation analysis, Bland Altman analysis, independent samples t-test and Kruskall Wallis test with a post hoc test for comparison. Results Both USCOM® and NICOM® show excellent repeatability and reproducibility. In the third trimester, USCOM® exceeds the clinical benchmark of 30% mean percentage difference (MPD) for acceptance of a new methodology; NICOM® has a 32% MPD in late pregnancy. There is moderate correlation between the two methodologies in the assessment of cardiac output. There is a significant effect of maternal age, height and weight on haemodynamic variables. An aberrant haemodynamic profile is exhibited in pregnancies complicated by obesity. Conclusion Published data regarding maternal haemodynamics obtained using non-invasive cardiac output monitors must be interpreted with caution in the absence of validation studies. USCOM® and NiCOM® have a mean percentage difference of around 30% in the third trimester of pregnancy, thereby suggesting that they can be used to investigate maternal haemodynamics at advanced gestations. Aberrant haemodynamics have been found in morbid maternal obesity. Reference ranges for common haemodynamic parameters obtained using USCOM®, as well as their interaction with maternal demographics are demonstrated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available