Abstract
Pheochromocytomas and paragangliomas are uncommon neuroendocrine tumors that present notable anesthetic challenges, especially in controlling blood pressure. The Hypotension Prediction Index (HPI) can be used for intraoperative hemodynamic monitoring and management. Here, we report the case of a 46-year-old woman diagnosed with paraganglioma who underwent laparoscopic retroperitoneal resection guided by a monitoring system with HPI. Overall, mean arterial pressure (MAP) and HPI displayed an inverted relationship during the anesthesia induction period and subsequent phases of the procedure. Her MAP, initially around 90 mmHg, reached 120-150 mmHg while intubated and during tumor manipulation, and thus intermittent doses of phentolamine were necessary to control hypertensive events. MAP then declined following ligation of the tumor's feeding vessels, accompanied by a corresponding rise in HPI values. Intraoperative hypotension was managed by HPI-based protocols, resulting in a very low time-weighted average-MAP (TWA-MAP) below 65 mmHg of 0.007 mmHg. While the minimum cross-correlation value between HPI and MAP occurred at a time lag of zero, indicating no delay between HPI and MAP, we found HPI alerted 3 to 17 minutes before MAP reached below 65 mmHg. We could add a new insight into the interpretation of cross-correlation analysis, that no time delay between HPI and MAP might not necessarily mean the predictive ability of HPI was low. Whereas this case highlights the potential of the HPI in mitigating intraoperative hypotension, future research is necessary to evaluate its predictive accuracy during paragangliomas resection.