Haemolysis during extracorporeal CO2 removal; a laboratory study using donated human blood.

Extracorporeal life support (ELS) has proven a successful technique to provide cardiopulmonary assistance in acute heart and/or lung failure. Adapted towards a low-flow application using low pump flows and small catheters, ELS can be used for extracorporeal CO2 removal in patients suffering from exacerbation of chronic obstructive pulmonary disease.



In this prospective study an in vitro setup will be filled with donated fresh human blood from healthy volunteers willing to donate approximately 200 ml. Different catheter sizes and flow rates are used (in triplo) in order to investigate a relationship between haemolysis (plasma free haemoglobin) and extracorporeal life support-related parameters such as pump flow, catheter selection, pump speed, pump pressures and pump heating.

Objective: to investigate in vitro a relationship between plasma free haemoglobin and extracorporeal life support-related parameters such as pump flow, catheter selection, pump speed and pump heating.

1. Blood flow is positively related to plasma free hemoglobin, circuit pressures and circuit temperature.

2. Decreasing catheter diameter aggravates the relationship between blood flow, plasma free hemoglobin, circuit pressures and circuit temperature.

After choosing a catheter size and flow rate, there are two main timepoints for recording data:

- 5 minutes after the start of the blood pump: pump speed (pump display), flow rate (pump display), pump inlet / outlet pressures (pump display), circuit temperature before and after pump (temperature probes), free haemoglobin (blood sample in duplo, laboratory maesurement).

- 6 hours after the start of the blood pump: pump speed (pump display), flow rate (pump display), pump inlet / outlet pressures (pump display), circuit temperature before and after pump (temperature probes), free haemoglobin (blood sample in duplo, laboratory maesurement).



Interim recordings (every hour) include blood flow rate, pump speed, temperature and circuit pressures.

30 healthy volunteers will donate approximately 200 ml whole blood, drawn by aseptic vena punction by an experienced physician and collected in a blood donation bag containing citrate for anticoagulation. Blood is donated under standard transfusion laboratory conditions, i.e. lying on a bed, with vital parameter monitoring, and fluid supply by drinking water during and after donation.