Hemodynamic management post-cardiac surgery is crucial for optimal patient outcomes. Hemodynamic instability is common, exacerbated by hypovolemia and vasodilation. The goal is to maintain perfusion and oxygen delivery, targeting variables like heart rate, mean arterial pressure, and central venous pressure. Fluid resuscitation is vital for early instability, addressing blood loss, vascular capacitance, fluid losses, and increased preload requirements. Assessing preload dynamics is challenging, with static pressures poorly predicting fluid responsiveness. Dynamic approaches like pulse pressure and stroke volume variation have limitations.

Plethysmographic perfusion index (PI) offers a non-invasive method to assess fluid responsiveness. PI, derived from pulsatile and non-pulsatile light absorption, reflects arterial volume changes during the cardiac cycle. PI varies with changes in vascular tone, making it a potential indicator of fluid responsiveness. Studies show correlations with vascular tone changes induced by anesthesia and vasopressors.

Our study aims to validate PI for detecting fluid responsiveness in postoperative cardiac patients during warming until peripheral temperature reaches 30 C. We’ll also explore the correlation between PI changes and fluid requirements. If proven reliable, PI could revolutionize non-invasive fluid assessment, aiding cardiac care providers in optimal postoperative fluid resuscitation.

Hypothesis:

There is correlation between change in plethysmographic perfusion index and postoperative fluid responsiveness in immediate postoperative period in patients who underwent cardiothoracic surgery.