The white blood cell response to splenectomy and bacteraemia

The aim of this study was to determine the relationship of the white blood cell (WBC) count to bacteraemia, and the risk of bacteraemia after splenectomy. The case series study was carried out at the Vanderbilt University Level I Trauma Center, and included 11,870 consecutive trauma admissions: 258 required a splenectomy (191) or splenorrhaphy (67). Bacteraemia was defined as the presence of a positive blood culture. Statistical analysis included ANOVA, the non-parametric Kruskal-Wallis test and logistical regression. Forty-two (22 per cent) of the splenectomy patients had positive blood cultures, while only six (9 per cent) of the splenorrhaphy patients had positive cultures. For the group of patients requiring a splenectomy, the mean WBC count was higher and more persistent in patients with bacteraemia. Logistical regression demonstrated that the type of surgery does not significantly correlate with bacteraemia after accounting for severity of injury (TRISS). The study conclusions were as follows (1) for the group of patients with bacteraemia after splenectomy, the peak WBC count was higher and more persistent than that which occurred in the group of patients without bacteraemia after splenectomy; (2) the WBC count cannot be used to predict bacteraemia for an individual patient, but a WBC count greater than 20,000 after 10 days should initiate a vigorous search for infection; (3) the severity of injury (and not splenectomy/splenorrhaphy) accounted for the increased risk of bacteraemia in population studied.