Effect of Splenectomy and Other Operative Procedures on Platelets as Determined Volumetrically

Abstract

An increase in the number of circulating thrombocytes has been observed following operations, 1 , 2 parturition 1 and fractures, 3 but is greatest after splenectomy. 4 , 5 This increase has been attributed to tissue injury 1 and in the case of splenectomy to additional factors, 6 The period of maximum increase coincides with that period in which post-operative thromboses are most likely to occur.

We have repeated the above observations using the volumetric method 7 of platelet determination, since this has proved to be more reliable in our experience than any method of counting and in addition indicates the amount of platelet substance present, rather than simply the number of platelets irrespective of their size. In normal subjects the platelets form from 0.4 to 0.6% of the whole blood volume.

Table I and Fig. 1 show that a variable but moderate increase in the platelets occurred following operations, while in the postpartum cases there was only a very slight rise. There was a striking increase after splenectomy although a considerable variation in the degree and rapidity of the rise was noted. One patient (Case 11) was followed intermittently for 3 years and at the end of this time the platelets were present in normal amounts. Only one splenectomized patient (Case 17) failed to show a noteworthy increase in platelets. This patient died of mesenteric thrombosis on the ninth post-operative day. Symptoms of this complication appeared on the seventh day while the last platelet determination, 24 hours previously, had shown no significant increase in these bodies.

These results correspond in general to those obtained by platelet counts and indicate that increase in the platelet volume is not the primary factor in post-operative thrombosis.