Endotracheal tube use helps maintain efficiency of Holmium lasers in flexible ureteroscopy with laser lithotripsy

Flexible ureteroscopy with laser lithotripsy is the standard treatment option for many types of kidney stones, however, many inefficiencies can potentially increase operative time and, therefore, the risk of complications. During surgery, the respiratory motion leads to clinically significant movement of the kidneys which can defocus laser energy from the stone and needs the surgeon to halt laser firing. This can be affected by factors such as body mass index (BMI) and ETT or LMA.

Newer Lumenis Pulse™ 120H holmium lasers provide access to previously unavailable intraoperative data including duration of pauses between laser activation and timestamps. David G. Gelikman, University of Central Florida College of Medicine, Orlando, Florida, and colleagues sought to utilize this data to calculate a “lasing inefficiency” percentage for each case to objectively identify anthropometric and surgical factors associated with decreased operative efficiency.

For this purpose, the researchers analyzed 48 intraoperative reports and patient data sets from an ongoing laser lithotripsy clinical trial that included metrics such as race, sex, age, kidney stone characteristics, and BMI. In each case, ureteroscopy was performed by a fellowship-trained, attending endourologist. Pauses between each laser firing were calculated using lasing activation start times and duration. Pauses longer than 30 seconds were excluded to account for navigation to change of instrumentation or to a different site.

The total lasing pause time was divided by the total lasing duration to produce a “lasing inefficiency” percentage for every case. Lasing inefficiency to patient demographics, stone burden, and anaesthesia administration were compared using both multivariate and univariate analysis.

The researchers reported the following findings:

· Patients who received an LMA had significantly higher lasing inefficiency (26.5%) compared to those who received ETT intubation (20.7%) in the univariate analysis as well as in the multivariate model.

· There were no significant differences in lasing inefficiency for the other study variables.

· Though BMI was not found to be significantly correlated with lasing inefficiency, the researchers noted that high patient BMI was significantly correlated with the use of ETT over LMA.

"Our data supports using ETT over LMA for reducing lasing inefficiency when using Holmium lasers in fURSL," the researchers wrote. "However, it remains one consideration among many when choosing between using an LMA or ETT."

Reference:

PD45-03 FACTORS AFFECTING HOLMIUM LASER INEFFICIENCY: COMPARISON OF LARYNGEAL MASK AIRWAY AND ENDOTRACHEAL TUBE USE DURING FLEXIBLE URETEROSCOPY FOR RENAL STONES. David G. Gelikman, Amy M. Reed, Naren Nimmagadda, Nicole L. Miller.