Basic Hemodynamics in Correlation With Noninvasive Cardiac Output: A Diagnostic Reliability Issue During Percutaneous Nephrolithotomy Bleeding Under Spinal Anesthesia

Hypothesis: On the concept of patient safety, using basic noninvasive monitoring tools (Blood pressure, HR, pulse oximetry O2 Saturation) are late and deceiving and non-reliable hemodynamic measuring tools in diagnosing the progression of the silent hidden bleeding during percutaneous nephrolithotomy surgery (PCNL) operations and necessitate adding noninvasive COP (bioimpedance based) monitor for minute to minute detection of the hemodynamic changes during (PCNL) surgery (necessitates high level spinal anesthesia and prolonged prone position with its hemodynamic burden, carries high risk of inaccessible uncontrollable bleeding).

The aim of the work:

Targeting more intraoperative patient safety by determination of the credibility of basic hemodynamic monitors in reflecting the real cardiopulmonary functions during PCNL operation (high risk is hidden bleeding) under prone position spinal anesthesia.

Achieved by using correlation between intraoperative noninvasive thoracic bioimpedance [COP -oxygenation] monitor and the usually used basic intraoperative [hemodynamic-oxygenation] monitoring systems; two outcome categories will be correlated; a)-Circulatory category: thoracic bioimpedance based COP hemodynamic parameters including (cardiac output COP-stroke volume SV -stroke index SI- cardiac index CI-cardiac performance index CPI-stroke volume variability SVV, systemic vascular resistance SVR, systemic vascular resistance index SVRI) correlation with the usual basic hemodynamic monitoring dependent parameters noninvasive blood pressure NIBP (systolic SBP and mean MAP) and the heart rate HR. b)- Oxygenation category: (Oxygen delivery (Do2), Oxygen delivery index (Do2I), correlation with the basic monitor pulse oximeter oxygen saturation (Sao2).

Correlation will be done at 3 times first basal (just after prone position adjustment and before PCNL puncture, after 60 min then after 120 minutes of prone position adjustment.