Time to reconsider saline as the ideal rinsing solution during abdominal surgery

Peritoneal mesothelial cells lining the peritoneal cavity play a primary role in prevention of formation of peritoneal adhesions, which depends mainly on their fibrinolytic activity. During surgical procedures, the abdominal cavity is in most cases rinsed with normal saline solution, which may modify the fibrinolytic activity of the peritoneal mesothelium and predispose to formation of adhesions. The goal of our experiments was to evaluate how normal saline and other solutions affect the fibrinolytic properties of the peritoneal mesothelial cells.

Experiments were performed on in vitro cultures of human peritoneal mesothelial cells. Mesothelial monolayers were exposed during 6 hours to the following solutions: culture medium (control), .9% NaCl, Hanks solution, Earles solution, new peritoneal dialysis fluid with low glucose degradation products (GDP) concentration (PDF), and peritoneal dialysis fluid with high concentration of GDP (PDF-GDP). Afterwards, morphology of the cells as well as leakage of lactate dehydrogenase (LDH) from their cytosol were evaluated. During the next 24 hours when the cells were cultured in standard medium synthesis of interleukin-6 (IL-6), tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) were studied.

Mesothelial monolayers exposed to .9% NaCl or to PDF-GDP showed destruction of their morphology after 6 hours incubation and in case of PDF-GDP release of LDH from the cytosol was increased by 275% versus the control (P<.05). During subsequent culture of all cells in standard medium, the release of IL-6 was decreased in cases of cells pretreated with .9% NaCl (-58%, P<.05) or PDF-GDP (-93%, P<.001). The release of t-PA was also reduced from cells pretreated with .9% NaCl (-71%, P<.01) or with PDF-GDP (-74%, P<.01) but increased after exposure of these cells to PDF (+35%, P<.05). Statistically significant decrease of PAI-1 synthesis was observed in cells preexposed to .9% NaCl (-69%, P<.01) or to PDF-GDP (-82%, P<.05). When changes in the PAI-1/t-PA ratio were calculated, a strong tendency for increase of that value was seen in cells pretreated with .9% NaCl or Earles salts solution but not with PDF. However, in cases of Hanks solution, a significant increase in the PAI-1/t-PA ratio was observed (+104%, P<.01).

Exposure of the peritoneal mesothelial cells to .9% NaCl, Hanks, Earles salts solution, or PDF-GDP results either in reduction of their viability or in loss of their fibrinolytic activity. Peritoneal dialysis fluid with a low content of glucose degradation products appears to be the optimal solution causing the least damage to mesothelial cells and therefore may be the ideal solution for rinsing the abdominal cavity with low risk of inducing deterioration of the mesothelial cells fibrinolytic activity and formation of adhesions. We postulate therefore that such hypertonic peritoneal dialysis fluids should be used not only during peritoneal dialysis but also for rinsing the abdominal cavity during any surgical procedures.