PREDICTION OF FLUID RESPONSIVENESS WITH PASSIVE LEG RISING IN PREGNANT PATIENTS WITH SEVERE PREECLAMPSIA
Condition: Pre-Eclampsia; Volume Overload; Hemodynamic Instability
MeSH terms: Pre-Eclampsia; Eclampsia
Study type: Observational [Patient Registry]

Summary: 
      BACKGROUND: A cornerstone of treatment in preeclampsia is to correct the potential
      hypovolemia with intravascular optimisation, which is usually performed as a fluid challenge.
      The prediction of fluid responsiveness in these patients, secondary to anatomical and
      physiological changes associated with pregnancy has not been established. This study aims to
      evaluate if Passive Leg Raising (PLR) protocol can predict fluid responsiveness in pregnant
      patients with severe preeclampsia.

      MATERIALS AND METHODS: in 35 pregnant women diagnosed with preeclampsia with a clinical
      indication to optimise intravascular volume, . A PLR manoeuvre and a fluid challenge will be
      performed, and hemodynamic parameters were recorded using Bioreactance technology.
      Descriptive statistical analyses, Pearson chi-square test, and mean standard deviation (SD)
      will be calculated. Analysis of proportion was used to calculate probabilistic intersections
      of the interventions. The area under curve, sensitivity, specificity, positive predictive
      value and negative predictive value were calculated for a delta of 12.

      Objective: to evaluate the if passive leg rising protocol identifies fluid responsivness in
      pregnant patients with preeclampsia
    

Detailed description: 
      INTRODUCTION The clinical manifestations of preeclampsia (PE) are the consequence of
      endothelial dysfunction. [1, 2] Different hemodynamic patterns have been described, which
      includes: high vascular resistance, cardiac output (CO) alterations, relative hypovolemia,
      and increased risk for pulmonary oedema, [3-6] which has been recognised as the most common
      final cause of death in women with complications of hypertension7. The risk of pulmonary
      oedema in preeclampsia is caused by different pathophysiological changes that follow the
      disease. It can be classified as increase preload caused by iatrogenic resuscitation and
      resolving puerperal oedema. Cardiac causes such as the presence of a myopathic ventricle,
      diastolic dysfunction, valvular heart disease, increased afterload caused by severe
      hypertension and increased vascular resistance, and other factors such as reduced oncotic
      pressure increased capillary permeability or a combination of all.

      A cornerstone of treatment to correct the potential hypovolemia in preeclampsia is
      intravascular volume optimization, which usually is performed as a fluid challenge, [8-9]
      However, the increased risk of pulmonary oedema has made us understand the need to use
      dynamic hemodynamic parameters for fluid responsiveness to guide optimal intravascular volume
      optimization in this group of patients.

      Monitoring fluid therapy upon clinical observation or the estimation of filling pressures
      using clinical markers such as blood pressure, pulse rate and urinary output as an endpoint
      of euvolemia may be inaccurate in women with severe preeclampsia. In critically ill settings
      the resolution of severe hypovolaemia is accompanied by rising blood pressure, falling of
      pulse rate and increasing the urinary output. However, in preeclamptic women, oliguria may
      develop because of intrinsic renal disease and may not respond to plasma volume expansion
      with an increase of urinary output. [20] Tachycardia commonly complicates severe
      preeclampsia, and a persistently rapid pulse rate may not be a reliable indication of
      intravascular volume depletion, especially when the systolic blood pressure is within
      reasonable limits.

      In the intensive care unit, patients with spontaneous ventilation, an increase of stroke
      volume during passive leg raising (PLR) predicts fluid responsiveness. [10-13] However,
      during pregnancy, the validity of PLR has been questioned, secondary to the known anatomical
      changes that occur from the compression of the inferior vena cava (IVC) by the gravid uterus
      and the presence of increased abdominal pressure. [14-16] However recently Brun20 published
      the first study that showed that PLR accurately predicts fluid responsiveness in the setting
      of Severe Preeclampsia.

      Thoracic bioreactance technology, [17] which is based on the analysis of thoracic voltage
      amplitude changes in response to a high-frequency injected current, and has the potential to
      be a useful noninvasive clinical tool for monitoring hemodynamics in pregnant women. However,
      the prediction of fluid responsiveness in these patients, secondary to anatomical and
      physiological changes associated with pregnancy has not been established.

      The objective of this protocol is to evaluate if PLR test can predict fluid responsiveness in
      pregnant patients with severe preeclampsia.

      MATERIALS AND METHODS The study is approved by the Institutional Review Board. Both ethic and
      research committee approved the protocol with registers number DI/17/112/03/039. Patients
      will be informed and signed consent before participation. Patients are going to be
      prospectively assessed, and consecutive measurements will be performed in an obstetric ICU of
      Mexico´s General Hospital Dr Eduardo Liceaga from December 2016 to July 2017. A sample was
      calculated for known variance P .01. Measurements for blood pressure and heart rate are made
      using bioreactance (NICOMTM Panamedical Mexico City, Mexico) technology.[18] The monitor will
      be placed at bedside, to monitor Systolic Arterial Pressure (SAP) and Diastolic Arterial
      Pressure (DAP), Stroke Volume (SV), Stroke Volume Index (IVS), Cardiac Output (CO) and
      Cardiac Index (CI).18 Because hemodynamic values may vary within a respiratory cycle,[17] an
      average of 10 consecutive cardiac cycles, over at least one respiratory cycle, was used for
      measurements of SAP, DAP, MAP, SV, and ISV.

      Moreover, we use the best dynamic index report under those 10 minutes. A PLR manoeuvre was
      performed for 3 minutes. The manoeuvre involved elevating the patient's legs and placing them
      on an inflatable leg wedge providing an angle of 45 degrees while in the supine position.
      Next, a 250 crystalloid /colloid (Hartmann + albumin 25%) bolus was given recording the same
      hemodynamic parameters to observe changes in dynamic measurements to compare both results and
      classified them as responder and non-responder. No determination or Central Venous Pressure
      or surrogate was made because of the accumulative evidence of the failure of this methods to
      detect changes in intravascular volume status. A change of 12% after PLR and bolus was used
      to consider a patient responder[20]. Finally, we used the values for ISV because it would be
      the better parameter (without the influence of heart rate and independent of the body area).

      STATISTICAL ANALYSIS Using SPSS 23 statistics Descriptive data analysis of patients will be
      performed for this purpose, a multivariable database will be constructed, and descriptive
      statistical analyses made. To evaluate the distribution between variables a Pearson
      chi-square test will be used. Mean standard deviation (SD) values, and analysis of proportion
      with the aim of knowing the probabilistic intersections. The area under the curve,
      sensitivity, specificity, negative predictive and positive predictive value will be
      calculated for 12 for ISV.
    

Intervention name(s): PASSIVE LEG RISING
Intervention type(s): Diagnostic Test
Intervention description(s): Pasive Leg Rising: In the supine method, the legs are lifted passively from the horizontal position to a 30° to 45° elevation while the head of the bed is flat.
Fluid Challenge: Fluid responsiveness is generally defined as an increase in SV or CO of 10% to 15% in response to a 250 mL crystalloid fluid bolus
Other intervention name(s): fluid challenge
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Female pregnant women with sever preeclampsia
      
Keywords: passive leg risging; Fluid challenge; Preeclampsia