Cold atmospheric plasma therapy as a novel treatment for Berlin Heart EXCOR pediatric cannula infections.

BACKGROUND: Cold atmospheric plasma (CAP) therapy has been recognized as effective treatment option for reducing bacterial load in chronic wounds, such as adult ventricular assist device (VAD) driveline exit-site infections. Currently, there have been no reports on the safety and efficacy of CAP therapy for pediatric cannula infections and inflammations in paracorporeal pulsatile VADs. METHODS: The mechanical strength of Berlin Heart EXCOR cannulas were tested both before and after CAP treatment (SteriPlas, Adtec Healthcare Limited, UK) to prove material safety. A ring tensile test of 20 untreated and 20 CAP-treated (5 min) EXCOR cannulas (Ø12mm), assessed the force at the breaking point of the cannulas (Fmax), at 25% (F25%) and 50% (F50%) of the maximum displacement. Additionally, the scanning electron microscope (SEM) micrographs for both groups examined any surface changes. Finally, the case of a 13-year-old male EXCOR patient with cannula infections, treated with CAP over 100 days, is presented. RESULTS: The in vitro measurements revealed no statistically significant differences in mechanical strength between the control and CAP group for F25% (8.18 ± 0.36 N, vs. 8.02 ± 0.43 N, p = 0.21), F50% (16.87 ± 1.07 N vs. 16.38 ± 1.32 N, p = 0.21), and FMAX (44.55 ± 3.24 N vs. 42.83 ± 4.32 N, p = 0.16). No surface structure alterations were identified in the SEM micrographs. The patient's cannula exit-sites showed a visible improvement in DESTINE wound staging, reduction in bacterial load and inflammatory parameters after CAP treatment without any side effects. CONCLUSION: Overall, CAP therapy proved to be a safe and effective for treating EXCOR cannula exit-site wound healing disorders in one pediatric patient, but further studies should investigate this therapy in more detail.

Human Factors Evaluation of HeartMate 3 Left Ventricular Assist Device Peripherals: An Eye Tracking Supported Simulation Study.

BACKGROUND: Despite recent design improvements, human factors issues continue to challenge left ventricular assist device (LVAD) therapy. The aim of this study was to evaluate user experience of former non-HeartMate 3 (HM3) LVAD patients post heart transplantation (HTX) and laypersons (LP) with HM3 LVAD peripherals in simulated everyday and emergency scenarios. METHODS: This single center cohort study included untrained HTX and LP. Seven scenarios, including battery exchanges (without alarm, advisory alarm, dim light, consolidated bag), change of power supply, driveline dis-/reconnection and controller exchange were simulated. Subjects' gaze behavior was recorded using eye tracking technology. Success rate, pump-off-time, duration to success (DTS), percental fixation duration per areas of interest and post-scenario-survey results were defined as outcome measures. RESULTS: Thirty subjects completed 210 scenarios, initially solving 82.4% (HTX vs. LP, p = 1.00). Changing power supply revealed highest complexity (DTS = 251 ± 93s, p = 0.76): 26.7% succeeded at first attempt (p = 0.68), 56.7% at second attempt, with significantly more LP failing (p = 0.04), resulting in 10 hazards from driveline disconnections (pump-off-time 2-118s, p = 0.25). Comparison on initial success showed differences in fixation durations for seven areas of interest (p < 0.037). Decreasing DTS during battery exchanges (p < 0.001) indicate high learnability. Exchanging batteries within the bag took longer (median DTS = 75.0 (IQR = 45.0)s, p = 0.09), especially in elderly subjects (r = 0.61, p < 0.001). Subjects with less initial success were more afraid of making mistakes (p = 0.048). CONCLUSION: This eye tracking based human factors study provided insights into user experiences in handling HM3 peripherals. It highlights unintuitive and hazardous characteristics, providing guidance for future user-centered design of LVAD wearables.

HeartMate 3 Snoopy: Noninvasive cardiovascular diagnosis of patients with fully magnetically levitated blood pumps during echocardiographic speed ramp tests and Valsalva maneuvers.

PURPOSE: The HeartMate 3 (HM3) left ventricular assist device (LVAD) has demonstrated excellent clinical outcomes; however, pump speed optimization is challenging with the available HM3 monitoring. Therefore, this study reports on clinical HM3 parameters collected with a noninvasive HM3 monitoring system (HM3 Snoopy) during echocardiographic speed ramp tests and Valsalva maneuvers. METHODS: In this prospective, single-center study, the HM3 data communication between the controller and pump was recorded with a novel data acquisition system. Twelve pump parameters sampled every second (1 Hz) and clinical assessments (echocardiography, electrocardiogram (ECG), and blood pressure measurement) during speed ramp tests were analyzed using Pearson's correlation (r, median [IQR]). The cause for the occurrence of pulsatility index (PI)-events during ramp speed tests and valsalva maneuvers was investigated. RESULTS: In 24 patients (age: 58.9 ± 8.8 years, body mass index: 28.1 ± 5.1 kg/m2, female: 20.8%), 35 speed ramp tests were performed with speed changes in the range of ±1000 rpm from a baseline speed of 5443 ± 244 rpm. Eight HM3 pump parameters from estimated flow, motor current, and LVAD speed together with blood pressure showed positive collinearities (r = 0.9 [0.1]). Negative collinearities were observed for pump flow pulsatility, pulsatility index, rotor noise, and left ventricular diameters (r = -0.8 [0.1]), whereas rotor displacement and heartrate showed absence of collinearities (r = -0.1 [0.08]). CONCLUSIONS: In this study, the HM3 Snoopy was successfully used to acquire more parameters from the HM3 at a higher sampling rate. Analysis of HM3 per-second data provide additional clinical diagnostic information on heart-pump interactions and cause of PI-events.