Endothelial protection: avoiding air bubble formation at the phacoemulsification tip

Abstract

[Purpose]: To investigate the conditions under which bubbles form during phacoemulsification. [Setting]: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. [Methods]: In the first part of the study, the partial pressure of oxygen (pO2) was used as a surrogate measure for the partial pressure of air. Irrigation solutions packaged in glass and plastic containers were studied. A directly vented glass bottle was also tested. The pO2 of the various irrigation solutions was measured as the containers were emptied. In the second part, phacoemulsification procedures were performed in rabbit eyes with different power settings and different irrigation solutions. Intracameral bubble formation during the procedure was recorded. Following the phacoemulsification procedures, the corneas were stained for F-actin and examined for endothelial injury. [Results]: The initial pO2 in irrigation solutions packaged in glass bottles was about half that at atmospheric levels; in solutions packaged in plastic, it was at atmospheric levels. As irrigation solutions were drained from the container, the pO2 of the solution tended to rise toward atmospheric levels. The rate of pO2 increase was markedly reduced by using a directly vented glass bottle. In the phacoemulsification procedures, bubble formation was most likely to occur with higher pO2 and higher power settings. Observation of bubbles by the surgeon was highly correlated with endothelial damage. [Conclusions]: Keeping the pO2 low reduced the risk of endothelial damage, especially at higher phacoemulsification powers. The packaging of irrigation solutions was the most important factor in controlling the initial pO2 of the solution. The pO2 can be minimized throughout a phacoemulsification procedure by using a directly vented glass bottle. J Cataract Refract Surg 2002; 28:531–537 © 2002 ASCRS and ESCRS