The role of intraoperative stroke volume variation on bleeding during functional endoscopic sinus surgery.

BACKGROUND: Functional endoscopic sinus surgery (FESS) is a minimally-invasive surgical technique for patients with paranasal sinus pathology. Surgical bleeding reduces operative field visibility and increases the incidence of serious complications. Epinephrine injection into the nasal mucosa and controlled hypotension are used to minimize bleeding. Hypotension carries risks and sometimes does not reduce surgical bleeding. The goal of this study is to discover which hemodynamic parameter better correlates with surgical bleeding.

METHODS: We enrolled 55 patients undergoing FESS. Inclusion criteria: male or female with chronic rhinosinusitis (CRS), older than 18 years, ASA I to III and primary surgery. Exclusion criteria: ASA>III, cerebrovascular and cardiac disorders, supraventricular tachycardia, renal or hepatic diseases, non-treated arterial hypertension, beta-blocking agent therapy, platelet-inhibiting agent or anticoagulant therapy, coagulopathy, pregnancy, clotting disorders, presence of neoplastic lesions and history of cranio-facial surgery. We used standard ASA plus ClearSight to assess hemodynamic parameters. Surgical procedures were performed by one surgeon and divided in ten surgical times (from T0 to T9). Intraoperative bleeding was assessed using the Fromme-Boezaart Scale.

RESULTS: Analysis between all the hemodynamic parameters registered and the Fromme-Boezaart Score showed a negative correlation between surgical bleeding and stroke volume variation (SVV) only. When dichotomizing according to Fromme-Boezaart Score (above or below 2), SVV was the only parameter which showed significant differences between groups. A cut-off of 12.5% in SVV is optimal to distinguish the group with the better surgical visibility from the group with the worst one.

CONCLUSIONS: Targeting SVV larger than 12% achieves a possible reduction of the intraoperative bleeding in patients undergoing FESS.