No abstract

SummarySyringe infusion pumps are used for the administration of short‐acting drugs in anaesthesia and critical care medicine, but are prone to flow irregularities at low flow rates. A flow‐controlled syringe infusion pump using an integrated flow sensor for feedback control represents a new approach to overcoming these limitations. This study compares the performance of a prototype flow‐controlled syringe pump both at start‐up, and during vertical displacement manoeuvres, with that of a standard infusion syringe pump. The novel pump almost completely eliminated delays at start‐up and flow irregularities during hydrostatic pressure changes. Related fluctuations in plasma drug concentration were minimised and the known disadvantages of standard syringe infusion pumps currently used in clinical practice were reduced. Besides providing fast start‐up to steady‐state flow and precise continuous drug delivery at low flow rates during hydrostatic pressure changes, the new pump offers the potential for the development of target‐controlled infusion algorithms for short‐acting cardiovascular and other drugs.

Ventricular assist devices (VADs) are an established treatment option for heart failure (HF). However, the devices are often plagued by material‐related hemocompatibility issues. In contrast to continuous flow VADs with high shear stresses, pulsatile VADs (pVADs) offer the potential for an endothelial cell coating that promises to prevent many adverse events caused by an insufficient hemocompatibility. However, their size and weight often precludes their intracorporeal implantation. A reduction of the pump body size and weight of the pump could be achieved by an increase in the stroke frequency while maintaining a similar cardiac output. We present a new pVAD system consisting of a pump and an actuator specifically designed for actuation frequencies of up to 240 bpm. In vitro and in vivo results of the short‐term reaction of the cardiovascular system show no significant changes in left ventricular and aortic pressure between actuation frequencies from 60 to 240 bpm. The aortic pulsatility increases when the actuation frequency is raised while the heart rate remains unaffected in vivo. These results lead us to the conclusion that the cardiovascular system tolerates short‐term increases of the pVAD stroke frequencies.