Wauters Joost, Claus Piet, Brosens Nathalie, McLaughlin Myles, Malbrain Manu, Wilmer Alexander
Medical Intensive Care Unit, University Hospital Gasthuisberg, Leuven, Belgium.
J Trauma. 2009 Mar;66(3):713-9. doi: 10.1097/TA.0b013e31817c5594.
Elevated intra-abdominal pressure (IAP) has been shown to impair renal perfusion and renal function. This study was designed to further investigate the effects of elevated IAP on renal venous hemodynamics and renal perfusion pressure (RPP). Another aim was to evaluate the renal cortical microcirculation by sidestream dark field (SDF) imaging in a porcine model of elevated IAP.
In 11 pigs, IAP was increased stepwise while renal hemodynamics and urinary output were recorded. RPP (RPP = mean arterial pressure minus IAP) and renal filtration gradient (RFG = mean arterial pressure minus 2xIAP) were calculated. Renal cortical microcirculatory perfusion was assessed by calculating the microvascular flow index (MFI) based on SDF data.
With IAP elevated to 30 mm Hg, renal arterial and venous flow decreased in parallel by 34% (p < 0.05) and RPP decreased by 12% (p < 0.05). With increasing IAP, renal vascular resistance increased and MFI decreased significantly. RFG showed a moderate correlation with renal blood flow (r = 0.39, p < 0.05) and MFI (r = 0.46, p < 0.005), whereas RPP did not.
In a porcine model of IAP-induced renal impairment, we observed a parallel decrease in renal venous and arterial blood flow together with blood flow redistribution away from the kidney. SDF imaging was used for the first time to assess renal cortical microcirculation and MFI was found to decrease with increasing IAP. RFG, as a clinical estimator of renal perfusion, correlated moderately with renal blood flow and microcirculatory perfusion, whereas RPP did not. Increased renal vascular resistance with elevated IAP might account for this.
腹腔内压力（IAP）升高已被证明会损害肾灌注和肾功能。本研究旨在进一步探讨IAP升高对肾静脉血流动力学和肾灌注压（RPP）的影响。另一个目的是通过侧流暗场（SDF）成像评估IAP升高的猪模型中的肾皮质微循环。
对11头猪逐步升高IAP，同时记录肾血流动力学和尿量。计算RPP（RPP = 平均动脉压减去IAP）和肾滤过梯度（RFG = 平均动脉压减去2×IAP）。根据SDF数据计算微血管血流指数（MFI），评估肾皮质微循环灌注。
当IAP升高至30 mmHg时，肾动脉和静脉血流平行下降34%（p < 0.05），RPP下降12%（p < 0.05）。随着IAP升高，肾血管阻力增加，MFI显著降低。RFG与肾血流量（r = 0.39，p < 0.05）和MFI（r = 0.46，p < 0.005）呈中度相关，而RPP则不然。
在IAP诱导的肾损伤猪模型中，我们观察到肾静脉和动脉血流平行下降，同时血流从肾脏重新分布。首次使用SDF成像评估肾皮质微循环，发现MFI随着IAP升高而降低。RFG作为肾灌注的临床评估指标，与肾血流量和微循环灌注呈中度相关，而RPP则不然。IAP升高导致肾血管阻力增加可能是其原因。
