Abstract
Purpose: :
The fluidics of cataract surgery are important for balancing the aspiration of emulsified nuclear material with maintaining the anterior chamber space. Both the cumulative dissipated ultrasound energy (CDE) and the volume of balanced salt solution (BSS) delivered in the eye during surgery can affect the postoperative condition of the cornea. Because more dense cataracts require higher CDE's and longer times in foot pedal position 3, the volume of fluid entering and leaving the eye should be greater. The volume of aspirated BSS can be used to calculate the volume escaping through the surgical wounds, and when compared to CDE, may be a new means to improve outcomes.
Methods: :
Using the Alcon Infiniti phacoemulsification platform, data was collected over 8 cataracts surgeries performed using a divide-and-conquer technique though a 2.4mm clear corneal wound and a 1.0mm side port incision. The beginning and ending volumes of fluid in the BSS bottle were obtained. Observations were made of the CDE and aspirated fluid volume per the Infiniti display. The volume of fluid delivered and the fluid lost through the incisions were calculated. The volume of BSS aspirated and the volume of BSS lost were then independently compared to the CDE.
Results: :
The 8 operations used between 110cc and 200cc of BSS, averaging 146cc. The aspirated volume ranged from 88cc and 105cc, averaging 94cc. The CDE ranged from 5.00 to 27.32, averaging 11.97. The volume of fluid lost ranged from 16cc to 102cc,averaging 52cc.The values of fluid lost versus the CDE can then be compared to the fluid aspirated versus the CDE. In general, the volume of fluid aspirated fluctuated within about 15cc’s despite an increasing CDE. However, the increasing fluid lost did tend to correspond to an increasing CDE.
Conclusions: :
Over the 8 cases investigated, similar volumes of fluid were aspirated in each surgery and this was independent of the CDE. However, cases with higher CDE's had larger losses of fluid through the wounds. This increase in fluid loss with increased CDE may be simply be due to increased surgical time spent undertaking surgical maneuvers for dismantling a dense nucleus. It may also be an indicator of wound architectural changes that are occurring during periods of longer ultrasound exposure and longer time spent with the phaco hand piece through the surgical wound. The fact that aspirated fluid volume remains stable over a range of CDE’s is likely a result from the increased efficiency of ultrasound delivery methods. Further studies may include comparisons of fluid aspirated versus fluid lost using different phaco modes, incision lengths, and removal techniques.