Predicting Neutrophil Recovery by Changes in Serum Electrolyte Levels of Stem Cell Transplantation Patients

Background:  The rapid hematopoietic cell expansion that leads to engraftment after SCT requires variety of metabolic and nutritional factors.  Hypophosphatemia , has been reported to precede engraftment (Raanani, et al.). Nurses have noted and we therefore hypothesized that phosphorous, calcium, and potassium values would drop 2-4 days pre-engraftment, when compared to either admission for conditioning (time point A) or day of transplant (time point B).  Being able to predict neutrophil recovery helps nurses be alert for clinical signs and symptoms of complications such as cytokine storm/engraftment syndrome, serious infection, and hyperacute graft versus host disease. 

 Methods:  We retrospectively reviewed records of 244 patients who underwent hematopoietic SCT from January 2005 through May 2006.  Electrolyte values were collected at the time of admission for conditioning (time point A); transplant day  (+/- 1 day; time point B); and 2-4 days prior to engraftment.  Two-sided paired t-tests were conducted comparing levels for each of the time points A and B compared to pre-engraftment.  For comparison between groups, two-sided two-sample t-tests were conducted.  No adjustment was made for the multiplicity of testing.  Patients were grouped as follows:  overall, by stem cell source (apheresis, bone marrow, or cord), transplant type (allogeneic or autologous), and CD 34 cell dose (>5 or ≤5 x 10⁶/kg, for apheresis products only).  Patients had their electrolyte levels measured while in the hospital, and received standardized electrolyte replacements.

 Results:  Overall, the values for all the electrolytes two to four days before engraftment were significantly lower than at time points A or B (p-value range <0.001 to 0.01 – Table 1). We concluded that drops in electrolyte levels precede neutrophil engraftment after peripheral blood SCT.  Being able to predict neutrophil engraftment will help nurses be more aware of possible SCT complications that may occur with engraftment, and allow the nurses to work with the medical team to intervene quickly.

  Table 1. Overall change from admission and transplant to pre-engraftment

Electrolyte	N	Timepoint	Average change to Pre-Engraftment	SD (change)	P-Value
Phosphorous	244	Admission (A) Transplant (B)	-0.6836 -0.4012	0.9956 1.0076	<0.001 <0.001
Calcium	242	Admission (A) Transplant (B)	-0.5851 -0.0971	0.7192 0.6008	<0.001 0.0126
Potassium	244	Admission (A) Transplant (B)	-0.2947 -0.2279	0.5642 0.5967	<0.001 <0.001