International coordinator survey results on the outpatient management of patients with the HeartWare® ventricular assist system.

PURPOSE: While the HeartWare® Ventricular Assist System (HVAS) is a successful therapy for end-stage heart failure, outpatient management methods can vary significantly and require further investigation. METHODS: A survey to assess the long-term HVAS patient management and monitoring strategies was completed by 36 international heart centers that currently have over 1,450 patients on VAD support either at home or in the hospital. Multiple choice questions examined VAD program characteristics, anticoagulation management, driveline exit-site dressing and showering recommendations, blood pressure and pump parameter monitoring, and patient discharge protocols. RESULTS: Outpatient international normalized ratio (INR) was most frequently measured every 3-4 days (28.6%), and the most frequent schedule for changing driveline exit site dressings was 3 times per week (30.6%). Only 25.7% of centers required their patients to measure blood pressure at home. A subgroup analysis was performed to assess the influence of center experience and larger centers generally had more frequent monitoring compared to smaller centers. CONCLUSIONS: This survey showed specific differences in outpatient management strategies that were previously unreported. However, further studies with correlations to patient outcomes are necessary to determine optimal patient management recommendations.

Adaptive multi-infusion decision support for the multivariable circulatory management of critically ill patients.

We have developed a novel adaptive multi-infusion advisory system for circulatory management of critically ill patients which co-ordinates infusion adjustments to ensure safe trajectories. This system should reduce patient hospital stay and improve patient outcome by enhancing the quality of patient circulatory control; alleviating the clinical cognitive load, giving staff more time for direct patient care, while also reducing infusion adjustment errors. We have applied three derived circulatory variables which relate to the three main types of cardiovascular infusions (inotropic, vasoactive and fluid). A lumped parameter steady flow model of the human circulatory system and the effects of cardiovascular infusions was constructed for algorithm development, clinical experts providing feedback on a representative test set of simulated patients in circulatory shock. Independent self-learning fuzzy logic controllers (SLFLC) were found to give good adaptation to variable patient infusion sensitivities. A supervisory, rule-based module co-ordinates infusion adjustments to ensure safe circulatory trajectories. Monitoring of manual infusion adjustments allows timely advice and also a critiquing capability which can train junior staff and reduce infusion adjustment errors. A physical mock circulatory loop was used to construct and test our physical advisory system. Preliminary clinical results show good clinical utility of our adaptive multi-infusion advisory system.