SISIPUSH: Evaluation of Hemolysis and Iatrogenic Anemia Using the Push-pull Method to Obtain Blood from Pediatric Patients with Central Venous Catheters

Anemia is frequently observed during hospitalizations, both in adults and children. In addition to the fact that anemia can be caused by an acute or chronic condition, blood samples taken during the hospital stay contribute to additional blood loss (so-called iatrogenic anemia).

For children, the relative amount of blood taken at each blood collection is greater than in adults. It is therefore expected that in children, due to the lower circulating blood volume, the relative impact of repeated blood sampling is greater and interventions such as sparing the number of blood samples or blood volume can have a relevant impact on the onset of anemia, the need for iron supplements or blood transfusions and the general clinical recovery.

For children, only limited data are available on the development of iatrogenic anemia during hospital stay. In a study of children in an intensive care unit, a decrease in hemoglobin of 0.7 g/dl can already be seen with an average stay of 4.5 days (and an average number of blood samples of 2.9) (François et al. Ped Crit Car Med, 2022). The average blood volume lost to blood samples during the stay is 3.9 ml/kg, which already corresponds to 5% of the total blood volume. Interventions to decrease the frequency of blood sampling or to perform the same analyses on a smaller blood volume (e.g. adapted, smaller blood tubes for children) are therefore useful in preventing the development of anemia during a hospital stay, especially in children.

Alternative methods have been described to save on blood volume when performing blood sampling, especially if these are performed via central venous catheters (surgically or non-surgically placed). To obtain a suitable sample via such catheters, the usual technique is to obtain 5 to 10 ml of blood and discard the volume (so-called "waste blood") before the sample for laboratory analysis is obtained (typically only 1-2 ml). A recently published technique is the so-called push-pull method (described by McBride et al, J Infus Nurs 2018), in which blood sampling can be performed without waste blood.

The push-pull technique has been studied in children, but mainly in oncological and intensive care units. Paired analyses have verified that the technique provides a reliable sample for most blood analyses, including blood count, electrolytes, liver and kidney function parameters, CRP, but also coagulation factors and therapeutic drug monitoring. The occurrence of complications, of which the development of catheter-related bacteremia is of particular importance, is not described. A beneficial effect on anemia onset has not yet been described, usually due to low patient numbers per study (23-35 patients).

In SISIPUSH, we compare the push-pull technique with the standard-of-care in hospitalised children who undergo blood sampling via a central venous catheter for diagnostic reasons (in the context of routine care). By means of a 1:1 randomization, eligible patients who gave informed consent are assigned to one of the two methods for the remainder of the hospitalization. From the moment of randomization until discharge from the hospital, data will be collected from the medical file that are collected routinely (number of blood samples, hemoglobin values, number of blood transfusions, markers of hemolysis, age and gender, reason for hospitalization, type of catheter) and compared between the two groups. In parallel, nurses score the easy of use and satisfaction with the procedure at each blood sample.