The goal of this observational study is to learn about the effects of anemia on sublingual microcirculation in patients undergoing goal-directed fluid therapy (GDFT) during surgery. The main question it aims to answer is: Does anemia, under the condition of goal-directed fluid therapy, lead to significant changes in sublingual microcirculatory parameters (such as microvascular density and perfusion)? Participants will include 54 patients scheduled for elective open radical gastrectomy (27 anemic vs. 27 non-anemic). Sublingual microcirculation will be assessed using a side-stream dark field imaging device at four time points: before anesthesia induction (T0), after induction (T1), after specimen removal (T2), and after anastomosis completion (T3). All patients will receive intraoperative GDFT guided by pulse pressure variation (PPV) and cardiac output (CO) via the Vigileo-FloTrac system.
Study Type
OBSERVATIONAL
Enrollment
54
This is an observational study. Participants are assigned to groups based on their preoperative anemia status (hemoglobin ≤10 g/dL vs. \>10 g/dL). No experimental intervention is administered. All patients receive standardized clinical care including goal-directed fluid therapy and open radical gastrectomy as per routine practice.
Shanghai Cancer Center, Fudan University
Shanghai, Shanghai Municipality, China
Total Vessel Density (TVD)
Total vessel density is defined as total vessel length (mm) per unit area (mm²), calculated as: TVD = total vessel length / area of the field of view. Sublingual microcirculation videos are acquired using a side-stream dark field imaging device (MicroScan, MicroVision Medical). Vessels with diameter \<20 μm are analyzed using MicroSee image management software. Three videos are recorded at each measurement time point, and the average value is reported.
Time frame: before anesthesia induction (T0), after anesthesia induction (T1), after specimen removal (T2), and after anastomosis completion (T3).
Perfused Vessel Density (PVD)
Perfused vessel density is defined as perfused vessel length (mm) per unit area (mm²), calculated as: PVD = perfused vessel length / area of the field of view. Perfusion is defined as continuous or sluggish flow (score ≥2 on the microvascular flow scale). Sublingual microcirculation videos are acquired using a side-stream dark field imaging device. Vessels with diameter \<20 μm are analyzed using MicroSee software. Three videos are recorded at this time point, and the average PVD value is reported.
Time frame: before anesthesia induction (T0), after anesthesia induction (T1), after specimen removal (T2), and after anastomosis completion (T3).
Proportion of Perfused Vessels (PPV)
Proportion of perfused vessels is defined as the percentage of total vessel length that is perfused, calculated as: PPV (%) = (perfused vessel length / total vessel length) × 100%. Perfusion is defined as continuous or sluggish flow (score ≥2 on the microvascular flow scale). Sublingual microcirculation videos are acquired using a side-stream dark field imaging device. Vessels with diameter \<20 μm are analyzed using MicroSee software. Three videos are recorded at this time point, and the average PPV is reported.
Time frame: before anesthesia induction (T0), after anesthesia induction (T1), after specimen removal (T2), and after anastomosis completion (T3).
Microvascular Flow Index (MFI)
Microvascular flow index is a semi-quantitative measure of microvascular flow velocity. The field of view is divided into four quadrants. Flow in each quadrant is scored as: 0 = no flow, 1 = intermittent flow, 2 = sluggish flow, 3 = continuous flow. MFI is calculated as the average score across the four quadrants (range 0-3, with higher scores indicating better microvascular flow). Sublingual microcirculation videos are acquired using a side-stream dark field imaging device. Vessels with diameter \<20 μm are analyzed. Three videos are recorded at this time point, and the average MFI is reported.
Time frame: before anesthesia induction (T0), after anesthesia induction (T1), after specimen removal (T2), and after anastomosis completion (T3).
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