Effect of pneumoperitoneum and steep reverse-Trendelenburg position on mean systemic filling pressure, venous return, and microcirculation during esophagectomy

Abstract

Background: Keeping adequate tissue perfusion during high-risk abdominal surgery is of utmost importance to decrease postoperative complications. The objective was to investigate the alteration in mean systemic filling pressure (MSFP), venous return (VR) and sublingual microcirculation during pneumoperitoneum and steep reverse-Trendelenburg position during thoracolaparoscopic esophagectomy.

Methods: This is a single-center prospective observational study in operating room at a university hospital. Eleven consecutive patients undergoing minimally invasive esophagectomy. Intraoperative hemodynamic and sublingual microcirculatory variables were simultaneously measured within 5 minutes at the following time points: T1, baseline supine position before the start of surgery; T2, pneumoperitoneum in supine position; T3, steep reverse-Trendelenburg position after the pneumoperitoneum. The cardiac output (CO) was obtained with continuous pulse contour waveform-derived measurements, and the MSFP was estimated with the analogue method.

Results: The pneumoperitoneum and reverse-Trendelenburg caused an increase in stroke volume variation (SVV), MSFP and central venous pressure (CVP), and a decrease in the microcirculatory perfusion index (MFI, <0.05). However, changes in CO, pressure gradient of VR, resistance of VR and blood pressure were not consistent and did not differ significantly across timepoints. Moreover, MFI is significantly related to CVP and MSFP but not to CO and blood pressure (BP). Measurements with MFI ≤2 have a higher CVP and MSFP compared to those with MFI >2. Using a CVP ≥23 mmHg to detect MFI ≤2 results in a sensitivity of 61.54% and a specificity of 100%.

Conclusions: A high CVP is related to poor microcirculatory flow perfusion even if the macrocirculation has been maintained during pneumoperitoneum.

Keywords: Microcirculation; central venous pressure (CVP); esophageal surgery; minimally-invasive laparoscopy.

Figure 1

Fluid optimization protocol. If stable and hemodynamic conditions were reached, the filling status of the patient was optimized: one or more boluses of 250 mL tetraspan 6% were given to determine optimal SV. Optimal SV was defined as the SV that no longer increased by more than 10% after a fluid bolus. During the operation, further colloid boluses were given only when the determined optimal SV declined more than 10% (the trigger SV). Baseline fluid maintenance (to correct for insensible loss) infusion was 1 mL/kg/h crystalloids (sterofundin, Braun). Other hemodynamic goals were: MAP >65 mmHg or <20% from baseline MAP, heart rate <100 bmp. SV, stroke volume; MAP, mean arterial pressure.

Figure 2

The change of CVP (A), MSFP (B), MFI (C) and PVR (D) over different time points. There was a significantly higher CVP and MSFP, and lower MFI at T3 when compared to T1. T1 = baseline position, T2 = pneumoperitoneum in supine position, T3 = pneumoperitoneum reverse-Trendelenburg. *, P<0.05 vs. T1. CVP, central venous pressure; MSFP, mean systemic filling pressure; MFI, microcirculatory perfusion index; PVR, pressure gradient for venous return.

Figure 3

The different values of MSFP (A) and CVP (B) during MFI ≤2 and MFI >2 measurements. There was a significantly higher MSFP and CVP during MFI ≤2 measurements. *, P<0.05. MSFP, mean systemic filling pressure; CVP, central venous pressure; MFI, microcirculatory perfusion index.

Figure 4

ROC cures comparing the ability of CO, MAP, CVP and MSFP to discriminate MFI ≤2. ROC, receiver operating characteristic curve; CO, cardiac output; MAP, mean arterial pressure; CVP, central venous pressure; MSFP, mean systemic filling pressure; MFI, microcirculatory perfusion index.