CO2 Flow Dynamics of Bladder Injury During Laparoscopy and the Effect of the Content of the Abdominal Viscera During Injury--Experimental Study.

ABSTRACT

BACKGROUND: Despite the well-known and easily recognizable signs of bladder injury during laparoscopy, some injuries remain unnoticed. Intra-operative diagnosis of a urinary bladder injury provides the opportunity to repair and prevent later complications involving the formation of fistula, infection, ascites and impairment of renal function. Small and unrecognized bladder injuries increase the chance of morbidity and permanent organ dysfunctions. OBJECTIVES: The aim of the study was to evaluate the CO2 flow dynamics of bladder injury occurring during laparoscopy and the effect of the content of the abdominal viscera during injury. MATERIAL AND METHODS: The study involved eight male New Zealand rabbits. Following urinary catheterization of the rabbits with an 8-gauge urinary catheter connected securely to a urinary drainage bag, pneumoperitoneum was created at a pressure level of 12 mm Hg. The experiment consisted of three phases. After the observational phase (Phase 1), the anterior wall of the urinary bladder was perforated with the tip of a 21 G needle (Phase 2) and methylene blue was administrated to evaluate the CO2 flow dynamics (Phase 3). RESULTS: The amount of CO2 consumption and accumulation in the urinary drainage bags differed significantly among the three phases of the experiment (p<0.05). There was no CO2 consumption or accumulation in the urinary drainage bags during Phase 1. The amount of CO2 consumption and accumulation in the urinary drainage bags during Phase 2 was significantly higher than during Phase 3. CONCLUSIONS: Urinary catheterization helps in the diagnosis of small or unnoticed urinary bladder injuries occurring during laparoscopy. CO2 flow and consumption is lower if the viscosity of the content overlying the injury site is higher.