The tissue glue, N-butyl-2-cyanoacrylate, is a watery solution that polymerises and hardens within 20 s in a physiological milieu and instantaneously on contact with blood. This makes it ideal for obliterating vessels and controlling bleeding. However,the rapid solid- ification of the glue makes endoscopic application, through a relatively long injection catheter, technically difficult because of the risk of polymerization within the catheter.
Before using any specific injection catheter, distilled water should be injected into the catheter with the precise amount of dead space determined (the dead space is approximately 0.8 mm in many catheters, but needs to be determined empirically). This is important so that after the glue has been injected into the varix with the syringe, the syringe is flushed with the precise amount of fluid (but not more) to empty the catheter of the glue.
While working with glue, all personnel need to wear gloves and goggles. The patient’s eyes are protected with a towel over the forehead and eyes. The gastroscope is placed in a retroflexed position juxtaposed to the varix in preparation for injection and the suction is turned off. The previously prepared catheter is inserted into the biopsy channel, and observed endoscopically. The catheter, with the needle still withdrawn, is advanced without variceal contact to ensure that the direction of the insertion leads to an appropriate site of potential injection into the varix. The needle is then pushed out and placed directly into the gastric varix. The catheter is injected with cyanoacrylate glue 1-2 ml followed by an injection of either Lipiodol or water (but not saline, which causes polymerization of the glue) equal to the dead space of the catheter to clear the rest of the glue. After the endoscopy assistant informs the endoscopist that the flush has been completed, the catheter is withdrawn from the varix with the needle still out and the catheter is continually flushed with water (or Lipiodol) until another injection of glue is needed. The endoscopist continually insufflates the stomach with air. If no further injections are thought to be needed, an attempt is made to withdraw the needle back into the sheath. If successful, the catheter can be used to palpate the injected varix (or varices) to ensure it is hard. If the varix is soft, further injections are needed.
Tissue necrosis may occur due to paravariceal injection, which may lead to deep ulceration and occasional perforation. Paravariceal injection can also cause early rebleeding if the varix is not completely obliterated.
Embolism is another rare but potentially serious complication. Emboli may go to the lung but systemic (arterial) embolization has also occurred. An important cause of increased risk of embolism during procedure is instillation of more than 1 mL of the cyanoacrylate glue per injection.