Can Continuous Cardiac Output Monitoring Before General Anesthesia Predict Hypotension After Induction?
Can Continuous Cardiac Output Monitoring Before General Anesthesia Predict Hypotension After Induction?
Post-induction hypotension (PIH) is very common with high incidence about 9-60%. There are
 multiple factors that may cause PIH, like pre-operative fasting, bowel preparation,
 vasodilatation due to anesthetics, and reduced stimulation during preparation before
 incision. Hypotension could cause tissue hypoperfusion, ischemia and higher risk for stroke
 or myocardial infarction, which result in higher risk for prolonged hospital stay or death.
 In general surgical patients, lower pre-induction SAP, older age (>50 years old), and
 emergency surgery are independently associated with PIH. In this study, we would like to use
 a wireless continuous non-invasive sonography device to evaluate if the change of cardiac
 output during the perioperative period could predict PIH.

 Ｗe would like to enroll 80 patients of ASA class I to III who undergo abdominal surgery.
 GIS-Heartio® will be used to estimate the cardiac parameters one day before the surgery (Day
 0) and after the patient enter the operation room till wound incision. Passive leg raise test
 would be performed on day 0 and before induction. We will analyze the patient's demographic
 data and the cardiac parameters to see if continuous cardiac output monitor can predict the
 occurrence of PIH.
Post-induction hypotension (PIH) is very common with high incidence about 9-60% in every kind
 of surgeries includes general anesthesia and neuraxial anesthesia. There are multiple factors
 that may cause PIH, like pre-operative fasting, bowel preparation, vasodilatation due to
 anesthetics, sympathetic blockade and reduced stimulation during preparation before surgical
 incision. Hypotension during the surgeries could possibly cause tissue hypoperfusion, tissue
 ischemia and higher risk for acute kidney failure, stroke or myocardial infarction, which
 result in higher risk for prolonged hospital stay or death [1-4]. In general surgical
 patients, lower pre-induction systolic arterial pressure, older age (>50 years old), and
 emergent surgery are independently associated with PIH[1].

 However, nowadays heart rate variability (HRV), the inferior vena cava(IVC) ultrasound, and
 stroke volume variation were demonstrated to be able to predict the PIH event [5-7]. However,
 people with any kind of arrhythmia is not suitable for HRV analysis. Part of obese patients
 are not suitable for IVC ultrasound due to poor image quality. Stroke volume variation can
 only be monitored if the arterial catheter and Flotrac® were applied on the patient before
 anesthetic induction.

 In this study, the wireless continuous non-invasive sonography device has the benefits of
 light-weighted, short learning curve, non-invasive, continuous monitoring, and more intuitive
 collected data. It's a huge progress for non-invasive cardiac output during anesthesia with
 GIS-Heartio®. The primary endpoint is if the change of cardiac output after fasting could
 predict PIH. The second endpoint is whether the change of cardiac output during "passive leg
 test" could predict PIH. If PIH can be predicted and prevented before anesthesia, the safety
 of the surgery and prognosis of patient will be elevated!
1. >20 years old

 2. American Society of Anesthesiologists Classification(ASA) I~III

 3. patients accept major surgery under general anesthesia, and monitored with invasive
 arterial blood pressure and estimated cardiac output.