Optimization of the Oertli CataRhex 3® phacoemulsification machine.

PURPOSE: The aim of this study was to determine optimal bottle height, vacuum, aspiration rate, and power settings of the Oertli CataRhex 3® phacoemulsification machine. METHODS: Porcine lens nuclei were hardened with formalin and cut into 2.0 mm cubes. Lens cubes were emulsified using the easyTip® 2.2 mm at 30°. Fragment removal time (efficiency) and fragment bounces off the tip (chatter) were measured. Settings tested included bottle height of 60, 80, 100 and 120 cm; aspiration rate of 40, 45, and 50 mL/min; vacuum of 400, 500, and 600 mmHg; and power of 50, 60, 70, 80, 90, and 100%. RESULTS: Efficiency and chatter increased in a linear fashion with increasing vacuum to 600 mmHg (P=0.017, P=0.046, respectively). The most efficient aspiration rate was 50 mL/min, although this finding lacked statistical significance (P=0.66). Increasing power increased efficiency up to 80% without increasing chatter (P=0.042, P=0.71, respectively). Compared to all other power settings, chatter was increased at 100% (P=0.014). CONCLUSION: The most efficient machine settings were vacuum at 600 mmHg, aspiration rate at 50 mL/min, and power at 80%.

The effect of increasing power when grooving using phacoemulsification.

PURPOSE: To determine optimal power settings on the Centurion Vision System during the grooving step in cataract surgery. METHODS: Intact porcine lenses hardened by formalin and placed in a chamber designed to simulate the anterior chamber of the eye were used to test longitudinal power at 40%, 70%, and 100% and torsional power at 0%. Flow rate was set at 40 mL/min. Vacuum was set at 400 mmHg, intraocular pressure was set at 50 mmHg, and a balanced phacoemulsification tip with a 20 degree tip and a 30 degree bevel was used. Efficiency (time to groove the lens in half) was determined. RESULTS: Increasing longitudinal power from 40% to 70% increased efficiency by 28% (P<0.05), and by 32% (P<0.05) when increasing longitudinal power from 40% to 100%. There was no statistically significant increase in efficiency from 70% to 100%. CONCLUSION: For the tested variables, a longitudinal power of 70% was determined to be most efficient during the grooving step of cataract surgery for equivalent 3-4+ nuclei. Further increases in power demonstrated no statistically significant improvement in efficiency.

Effect of increasing flow when grooving during phacoemulsification.

PURPOSE: To determine optimum flow settings on the Centurion Vision System during the grooving step in cataract surgery. SETTING: John A. Moran Eye Center Laboratory, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Intact porcine lenses hardened by formalin and placed in a chamber designed to simulate the anterior chamber of the eye were used to test flow rate settings at 20 mL/min, 40 mL/min, and 60 mL/min. Vacuum was set at 400 mm Hg, longitudinal power at 80%, torsional power at 80%, and intraocular pressure at 50 mm Hg. A balanced phaco tip with a 20-degree tip and a 30-degree bevel was used. Efficiency (time to groove the lens in half) was determined. RESULTS: Increasing flow from 20 to 40 mL/min during grooving increased efficiency by 17% (P = .05), with no significant improvement shown at 60 mL/min. CONCLUSIONS: A flow rate of 40 mL/min was determined to be most efficient during the grooving step of cataract surgery. Further increases in flow rate showed no statistically significant improvement in efficiency, and with only 17% improvement flow rates less than 40 mL/min might be almost as efficient and might be safer.

Identification of Nocardia Species by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of Nocardia species remains challenging. By identifying 83.1% (64 of 77) and 80% (8 of 10) to the species and complex levels, respectively, and 94.3% (82 of 87) to the genus level, we show that an approach using routine sample preparation, an up-to-date commercial database minimally augmented with custom spectra, and testing at an early stage of growth is promising.