Respiratory Variation of Carotid Doppler Peak Velocity (CDPV) for Non-invasive Prediction of Fluid Responsiveness

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to assess respiratory variation of carotid doppler peak velocity (∆CDPV) for prediction of fluid responsiveness during major abdominal surgery.

Detailed Description
-----------------
Investigating hemodynamic parameters in a group of 19 ICU-patients with septic shock, respiratory variation of carotid doppler peak velocity (∆CDPV) has been shown to be able to predict fluid responsiveness. For patients receiving so called lung protective ventilation with a tidal volume of 6ml/kg ∆CDPV was superior for prediction of fluid responsiveness when compared to other well established parameters such as pulse pressure variation (∆PP). Likewise in another study ∆CDPV has been shown to be superior to stroke volume variation (∆SV) for prediction of fluid responsiveness in patients with septic shock when ventilated with a tidal volume of ≥8ml/ kg. All in all respiratory variation of carotid doppler peak velocity (∆CDPV) seems to be a promising parameter for prediction of fluid responsiveness (Yao et al., BMC Anesthesiology 2018). However, so far clinical studies have been conducted only under a small number of patients mainly in the intensive care unit and/ or under highly specific conditions (e.g. cardiac surgery). If ∆CDPV is able to predict fluid responsiveness with high accuracy intraoperatively remains unknown. The investigators are therefore conducting this prospective monocentric observational trial to evaluate the performance of ∆CDPV during major abdominal surgery and compare it to validated fluid responsiveness monitoring parameters ∆PP and corrected flow time (fTc). Following IRB-approval and written informed consent 84 patients scheduled for major abdominal surgery will be enrolled in the study. Stroke volume will be monitored by Esophageal Doppler Monitoring (CardioQ-ODM®, Deltex Medical Ltd, Chichester, UK). In case of hypovolemia a fluid bolus of 7 ml/kg ideal body weight will be administered at the discretion of the attending anesthesiologist. Respiratory variation of carotid doppler peak velocity (∆CDPV) will be monitored before and 1 minute after completion of each fluid bolus using an ultrasound device with a common linear array transducer (Philips ClearVue 350, Philips Medizin Systeme GmbH, Boeblingen, Germany).

Official Title
-----------------
Assessing Respiratory Variation of Carotid Doppler Peak Velocity (CDPV) for Non-invasive Prediction of Fluid Responsiveness During Abdominal Surgery: a Prospective Observational Trial

Conditions
-----------------
Hemodynamic Instability

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age 18-80 years written informed consent scheduled major abdominal surgery Exclusion Criteria: Age <18 or >80 years pregnancy SIRS or sepsis any kind of cardiac arrhythmia known valve disease known heart failure any kind of known carotid stenosis carotid doppler peak velocity >182 cm/s before baseline measurement (expected stenosis) missing indication for invasive arterial blood pressure monitoring (IBP) not related to the study peripheral artery disease (PAD) BMI > 35 kg/m2 intraabdominal hypertension ASA-PSC of 4 severe lung disease (e.g. COPD grade 3, fibrosis) esophageal disease of any kind participation in another clinical study

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in stroke volume following a fluid bolus. | A rise in stroke volume of ≥10% following a fluid bolus of 7ml/kg Ideal Body Weight is considered to reflect fluid responsiveness. Measurements will be assessed through esophageal doppler monitoring. | Immediately before and 1 minute after completion of each fluid bolus. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Fluid Challenge, Fluid Responsiveness, Hemodynamic Monitoring, Carotid Doppler Peak Velocity, Pulse Pressure Variation