Impedance Cardiography to Decrease the Risk of Preeclampsia

To determine if the use of impedance cardiography can identify appropriate medications for use in treating chronic hypertensive patients to decrease the risk of preeclampsia.

Impedance cardiography helps determine whether vasoconstriction or an elevated cardiac output is occurring. The test is easy to perform and non invasive. The treatment for an elevated cardiac output in pregnancy is a beta-blocker while a vasodilator is used for vasoconstriction. If a beta-blocker is given to someone that vasoconstricted, this might make the cardiovascular parameters worse, leading to no improvement in future pregnancy issues. Likewise, if a vasoconstricting drug is given to someone with an elevated cardiac output, it could potentially make the cardiovascular parameters worse. All centers in the United States that choose to prescribe an antihypertensive medication for use in pregnancy do so by trial and error, whereas impedance cardiography can help the clinician choose the best medication from the start. Many pregnant patient patients have chronic hypertension and this population is at increased risk for superimposed preeclampsia and other pregnancy complications. The current recommendation for pregnancy is to NOT treat mild hypertension because studies have not shown any benefit. These studies, have also not shown any harm. Prior studies that have shown no benefit to treatment of mild hypertension in pregnancy may be hampered by choosing the wrong antihypertensive medication, thereby not improving the rate of superimposed preeclampsia and other pregnancy related complications.