Microcirculatory changes during goal-directed or mean arterial pressure-guided fluid therapy in abdominal surgery
KeywordsMean Arterial Pressure Cardiac Index Fluid Therapy Pulse Pressure Variation Microvascular Perfusion
This study compared the effect of pulse pressure variation (PPV) and cardiac index (CI)-guided fluid therapy versus mean arterial pressure (MAP)-guided fluid therapy on microcirculatory perfusion in patients undergoing abdominal surgery.
Patients undergoing elective abdominal surgery were randomized into a PPV/CI-guided group (n = 11) or a MAP-guided (n = 12) group. PPV, CI and MAP were measured using the non-invasive finger arterial blood pressure measurement device ccNexfin (Edwards Lifesciences BMEYE, Amsterdam, the Netherlands). Tidal volumes were ≥8 ml/kg with PEEP ≥8 mmHg. In both groups, MAP of 70 mmHg was maintained. In the PPV/CI group, an intraoperative algorithm was used keeping the PPV under 12% and CI above 2.5 l/minute/ m2 using fluid therapy and dobutamine and noradrenaline infusion, respectively. Sublingual microvascular perfusion was measured after anesthesia induction, and every subsequent hour using sidestream dark-field imaging (Microscan; Microvision Medical, Amsterdam, the Netherlands). The perfused small vessel density (PVD) values were offline quantified.
The first hour during surgery, the PPV/CI-guided group tended to receive more fluids than the MAP-guided group (1,014 ± 501 ml vs. 629 ± 463 ml; P = 0.07). At this time point, the PVD was slightly lower in the PPV/CI-guided group (16.7 ± 3.1 mm/mm2) when compared with the MAP-guided group (17.9 ± 3.9 mm/mm2; P = 0.41). In both groups the PVD remained stable during the first 2 hours of surgery. However, 2 hours after the start of surgery, the PVD in the PPV/CI group restored and tended to be higher than in the MAP-guided group (21.1 ± 1.9 vs. 18.1 ± 3.4 mm/mm2; P = 0.09). After 1 hour of surgery, the administered fluid volume correlated inversely with PVD (r = -0.59, P = 0.011).
Goal-directed fluid management resulted in a higher administered fluid volume in the beginning of surgery, and this was associated with a slightly reduced microcirculatory perfusion when compared with MAP-guided fluid management. Microcirculatory perfusion tended to improve as surgery progressed in the goal-directed fluid therapy group. Our findings suggest that goal-directed and MAP-guided fluid management are associated with distinct patterns in fluid resuscitation, which may be of consequence for microvascular perfusion.
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