Air bubble injection may be a source of endothelial damage in DSAEK

San Francisco-Results of a study using an ex vivo model suggest a possible role for air bubble-induced trauma in loss of endothelial cell density after Descemet’s stripping automated endothelial keratoplasty (DSAEK), said Anna Hong, MD, a resident at the Duke University Eye Center, Durham, NC.

“Donor adherence is often promoted by the use of an intraoperative air tamponade that presses the donor graft up against the host cornea and leaves a partial air bubble in the eye,” Dr. Hong said. “It is reasonable to expect that this air bubble can cause damage to the donor endothelium as the bubble shifts position with changes in head position.”

To investigate graft endothelial cell injury induced by air bubbles, an ex vivo DSAEK model was created. Six pairs of human donor corneas were sectioned using an automated microkeratome system. One cornea of each pair was mounted on an artificial anterior chamber and an air bubble was injected to fill 40% of the anterior chamber. Then, the apparatus was rotated 180° for 50 times to simulate in vivo air bubble motion from head movement. The fellow cornea of each pair served as a control.

The endothelial lamellar grafts of all corneas were removed and stained, and when analyzed for the proportion of viable endothelium, the results showed it was significantly lower in eyes with the injected air bubble compared with the control group, 79.8% versus 89.9%.

“Our study has several limitations. In vivo conditions cannot be truly reproduced and our method of simulating air bubble motion may be an under- or overestimation,” Dr. Hong said. “In addition, our sample size is small and further study is needed. However, our findings suggest that the potential benefits of introducing an air bubble during surgery should be weighed against its potential harm.”