Performance of the On-Q pain infusion device during hyperbaric therapy

There are reports in the literature regarding the effects of hyperbaric conditions on various medical devices. In the current study we evaluated the performance of an elastomeric infusion device during exposure to a hyperbaric environment.

Nineteen disposable 400-mL On-Q pain ball infusion devices were filled with 0.2% ropivacaine and connected to an infusion catheter. The regulator of the device was set to deliver 14 mL/h. Hyperbaric oxygen therapy included 7 minutes to achieve the desired hyperbaric pressure level, 90 minutes at the specific pressure (atm), and 7 minutes to return to normal atmospheric pressure (1 atm), thereby resulting in a study interval or dive of 104 minutes. The trials were performed for the devices in the following sequence of dives with a return to 1 atm between: 1, 2, 2.4, 2.8, 3, and 1 atm. The fluid delivered during each dive was measured with a graduated column. Additionally, the collection device was weighed before and at the completion of each dive to determine the change in weight as a measure of the total amount of fluid infused. The output over 104 minutes was also studied in 5 infusion devices without hyperbaric pressure (control group).

No difference in output of the devices was noted when comparing the study group and the control group. Although there was a decrease in the output of the devices over 8 to 9 hours, no difference between the 2 groups was noted.

This preliminary investigation demonstrates no clinically significant change in the function of the On-Q pain device during exposure to a hyperbaric environment.