Hemodynamic Optimization During Major Urological Surgery

Correlation Between IN-TArget Time for Mean Arterial Pressure and Stroke Volume During Major Urological Surgery and Tissue Perfusion: the INTAT Observational Study

In this prospective observational study investigators aim to seek for any possible correlation between the venous to arterial carbon dioxide difference (pCO2 gap) at the end of surgery and the percentage of time spent above a predefined threshold of stroke volume (SV) andn mean arterial pressure (MAP).

During major urological surgery (i.e. cistectomy) investigators will use a minimally invasive hemodynamic monitoring system (Flotrac - Vigileo, Edwards ) to guide fluid therapy and vasopressors administration. More specifically stroke volume target will be defined as the maximum SV after a series of fluid boluses, with a 10% tolerance. MAP was considered adequate if above 65 mmHg. After the induction of anesthesia, then each hour during surgery until the end of surgical procedure investigators will assess the time of adherence to the hemodynamic protocol (in terms of both SV and MAP) and the correspondent pCO2 gap. Investigators expect to find an inverse proportionality between the two parameters explored.

Inclusion Criteria:

• patients scheduled for major urological surgery
• ASA 1-2-3

Exclusion Criteria:

• pregnancy
• obesity with a BMI > 35
• controindications to central venous catheter positioning
• end-stage renal disease