Impact of different syringe pumps on red cells during paediatric simulated transfusion

A miniaturized 3D printed pressure regulator (µPR) for microfluidic cell culture applications

Well-defined fluid flows are the hallmark feature of microfluidic culture systems and enable precise control over biophysical and biochemical cues at the cellular scale. Microfluidic flow control is generally achieved using displacement-based (e.g., syringe or peristaltic pumps) or pressure-controlled techniques that provide numerous perfusion options, including constant, ramped, and pulsed flows. However, it can be challenging to integrate these large form-factor devices and accompanying peripherals into incubators or other confined environments. In addition, microfluidic culture studies are primarily carried out under constant perfusion conditions and more complex flow capabilities are often unused. Thus, there is a need for a simplified flow control platform that provides standard perfusion capabilities and can be easily integrated into incubated environments. To this end, we introduce a tunable, 3D printed micro pressure regulator (µPR) and show that it can provide robust flow control capabilities when combined with a battery-powered miniature air pump to support microfluidic applications. We detail the design and fabrication of the µPR and: (i) demonstrate a tunable outlet pressure range relevant for microfluidic applications (1-10 kPa), (ii) highlight dynamic control capabilities in a microfluidic network, (iii) and maintain human umbilical vein endothelial cells (HUVECs) in a multi-compartment culture device under continuous perfusion conditions. We anticipate that our 3D printed fabrication approach and open-access designs will enable customized µPRs that can support a broad range of microfluidic applications.

Influence of Peripherally Inserted Central Catheters With Proximal Valves on Red Blood Cell Hemolysis During Transfusion

The aim of this study was to verify the occurrence of hemolysis after infusion of packed red blood cells (PRBCs) in 12 peripherally inserted central catheters (PICCs) with a proximal valve, according to size and infusion rate. This was an experimental in vitro study performed under laboratory-controlled conditions, and the sample was composed of 12 PICCs with proximal valves (3F and 4F catheter). Twelve type A+ aliquots from 10 PRBCs were analyzed preinfusion and postinfusion according to PICC size and infusion rate. Hemolysis markers, total hemoglobin (g/dL), hematocrit (%), free hemoglobin (g/dL), potassium (mmol/L), lactate dehydrogenase (U/L), and rate of hemolysis (%) were studied. Data were analyzed using analysis of variance and Bonferroni multiple comparison tests. After the infusions in 3F PICCs, an increase was seen in rate of hemolysis (P = .003) and free hemoglobin (P = .014), in addition to a reduction in total hemoglobin (P = .002), with significant influence of minimum and maximum flow rates on the rate of hemolysis. The study finding indicated that the smaller catheter size and the infusion rate influenced variations in some hemolysis markers, but the alterations observed in the hemolysis markers would not contraindicate the infusion of PRBCs by 3F and 4F PICCs with proximal valves.