The hemodynamic effects of CO2-induced pressure on the kidney in an isolated perfused rat kidney model.

Division of General Surgery B, Tel Aviv Sourasky Medical Center, The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Surgical laparoscopy, endoscopy & percutaneous techniques (Impact Factor: 0.88). 12/2008; 18(6):573-8. DOI: 10.1097/SLE.0b013e3181875ba4
Source: PubMed

ABSTRACT Variable mechanisms were suggested to mediate the changes in renal hemodynamics during pneumoperitoneum. To assess whether it can be pressure dependent only, we conduct a study in an isolated, pressurized, and perfused organ model.
Seventy Wistar rat kidneys were perfused with oxygenated, 3% albumin-contained Krebs-Henseleit solution. Experiments took place within Plexiglass chamber that provided conditions for perfusion of organs, humidity, and maintenance of intracameral CO2 pressures [0 (control), 3, 5, 8, 12, 15, and 18 mm Hg]. All kidneys (10/group) were perfused for 60 minutes. One-half of the groups were perfused for an additional 30 minutes, during which the perfusion pressures were reduced to 0 mm Hg. pH of the perfusate was measured as well.
The perfusion pressure increased and the kidney flow decreased slightly, in proportion with the intrachamber pressure. Urine output decreased to a minimum of 40% in >or=8 mm Hg pressure conditions, compared with the control group. The pH values were below normal, during experimental pneumoperitoneum.
Pneumoperitoneal conditions are a direct cause of changes in renal urinary output. The increase in pCO2 pressure and consequently low intraorgan pH may contribute to a mild transient renal damage during pneumoperitoneum.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Aiming the principles of open partial nephrectomy, warm ischemia time is the limiting factor especially in case of central or complex tumors in laparoscopy. We demonstrate a novel solely laparoscopic technique for in situ cold perfusion of kidneys with direct catheterization of the renal artery to increase the tolerance of renal parenchyma for ischemia. In two patients with hilus compromising tumors, renal artery was clamped; a small incision in the artery was used to place a 5Fr centrally open angiographic balloon catheter and blocked with 1 ml NaCl. The kidney was perfused with 4°C Ringer solution. After tumor excision, the kidney was subsequently reconstructed by mattress bolster sutures and fibrin glue. The arterial incision was closed by a 4/0 Prolene suture. Both patients had an uneventful follow-up without neither intraoperative nor postoperative complications. No intraoperative body temperature drop occurred. Cold ischemia time was 66 (men, 65a) and 60 min (women, 43a), respectively. Hemoglobin drop was 4.1 and 1.9 g/dl; no transfusion was necessary. Preoperative and postoperative creatinine levels were 0.90 and 0.76 mg/dl, and 1.3 and 0.9 mg/dl, respectively. Patients were discharged on day 12 and day 8. Histology revealed clear cell RCC (pT1b pNx pMx G2 R0) in the first patient and oncocytoma in the second patient. Postoperative CT angiograpy demonstrated no sign of arterial insufficiency. Intraarterial renal cooling could expand the ischemia time and therefore the indication of laparoscopic partial nephrectomy in complex exposition. Furthermore, the identification of tumor borders and injured vessels is facilitated by the outflow of the cooling solution. Further investigations into this promising method could proof its feasibility in everyday clinical routine.
    World Journal of Urology 10/2010; 29(3):337-42. · 2.89 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pneumoperitoneum-associated ischemia-reperfusion (IR) may initiate renal dysfunction. Whether oxidants are responsible for renal structural damage, such as cell apoptosis, has not yet been evaluated. We investigated such eventuality in an isolated rat kidney model. Thirty-five rat kidneys with their vessels and ureter were harvested and perfused within a closed environment at flow of 15 ml min(-1). After stabilization, kidneys were assigned to one of five groups (n = 7 per group): CO(2)-induced intrachamber pressure of 8, 12, or 0 mmHg (control), and 8 or 12 mmHg pressure applied to kidneys from rats treated pre-experimentally with tungsten for 14 days. Pressurization lasted 60 min. Organ perfusion pressure raised as intrachamber pressure increased. Urinary output decreased in the two pressurized nonpretreated groups. Intrachamber pressure was directly associated with an increase in postexperimental xanthine oxidase tissue levels. Twofold apoptosis was documented (p < 0.05) in cortex of nonpretreated kidney in the 12 mmHg group compared with the 8 or 0 mmHg groups. Tungsten pretreatment significantly (p < 0.05) attenuated the abnormalities documented in the 12 mmHg group, but less so in the 8 mmHg pressurized nontreated counterparts. Pneumoperitoneal pressure applied to isolated perfused kidney is associated with renal apoptosis. This rapidly induced structural renal damage is oxidant dependent and can be attenuated by antioxidants. Further studies may shed more light on the role of antioxidants in preventing pneumoperitoneum-induced kidney dysfunction.
    Surgical Endoscopy 12/2011; 26(5):1417-24. · 3.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Molecular dynamics (MD) simulations have been used to study the adsorption of dodecylamine (DDA) on iron surfaces in aqueous solution in this paper. In strong acidic solution the protonated form of DDA, DDAH, can adsorb on the iron surface preferentially, while in weak acidic solution containing chloride ions the adsorption of DDA and DDAH forms can occur simultaneously. Different results were obtained when different simulation factors were considered. In order to obtain the correct results, a model close to the realistic inhibition system was fabricated.
    Corrosion Science - CORROS SCI. 01/2011; 53(5):2046-2049.