Abstracts

There is currently no standard protocol for initiation and titration of VNS. In published literature, titration is often completed over multiple outpatient visits spanning up to several months. However, slow titration may delay effective therapy and may increase costs. We have traditionally performed more rapid titration over one visit and report our experience. We performed a retrospective chart review on 64 patients who had initial ramp-up of a first VNS device. Replacement VNS was excluded. Patients were separated into two groups, those whose stimulus had not yet been turned on and those whose stimulus was turned on to 0.25 mA in the operating room. Data collected from each chart included gender, age at implant, time between each 0.25 mA increase in stimulation, adverse effects reported during steps of ramp-up, whether the device was titrated back due to adverse effects, the final discharge stimulus and the total amount of time spent for the visit. There were 36 men and 28 women, with a mean age of 33 [plusmn] 13 years (median 31, range 8-68). All patients received standard parameter settings of 500 [micro]s pulse width, 30 s on, 5 minutes off. Forty-six patients who started with 0.00 mA achieved a final output current of 0.76 [plusmn] 0.28 mA (median 0.75, range 0.25-1.50), accomplished over 37 [plusmn] 45 min (median 19, range 1-213). Two of the patients did not have total programming time recorded but were discharged at 1.00 mA in one visit. The mean interval was 9 min for the 2nd increase (0.50 mA), 23 min for 3rd increase (0.75 mA) and 34 min for the 4th increase (1.00 mA). Eighteen patients who started with 0.25 mA stimulation reached a mean final output current of 0.89 [plusmn] 0.32 mA (median 1.00, range 0.25-1.50), accomplished over 62 [plusmn] 78 min (median 50, range 1-270). This included one patient without documented total programming time who achieved a final output current of 0.50 mA at the end of one session. Fifteen (23%) of the patients experienced symptoms requiring backward titration during ramp-up; the causes included cough (7), throat discomfort (4), facial discomfort (1), choking (1), ear pain (1), feeling scared (1). In 14 patients, reducing stimulus by 0.25 mA controlled the symptoms; in the remaining case the stimulus was reduced by 0.50 mA. Our patients tolerated well the rapid titration of VNS and many achieved stimulation parameters within a desirable range in a single visit. Rapid titration may be beneficial to patient therapy with VNS, by achieving therapeutic stimulation levels without unnecessary delay and programming costs. This may be particularly useful for patients who must travel long distances for VNS programming.