The Change Of Platelet Function In Children With Acute Trauma During Operation

Objective:After acute trauma,abnormal platelet count and platelet dysfunction is often seen, that can directly influence the prognosis. But reports about the changes of platelet count and platelet function in children after acute trauma was little. The study was to investigate the changes of the platelet count and platelet function in children aged 4-12 undergoing lower extremity orthopedic surgery after acute trauma, and to discuss the causes and mechanism of the change.Methods:Fourty children aged 4-12 underging lower extremity orthopedics traumatic opertiaon after acute trauma were divided into two groups(n=20 each):Group A (minor trauma, Pediatric Trauma Score> 8) and Group B ( severe trauma, Pediatric Trauma Score≤8). Patients with any of the following were excluded from the study:(1) hematological diseases;(2) throm-bocyte dysfunction and hepetic or renal dysfunction; (3) the history of thromboembolism;(4) use of drugs contributing to coagulation function and platelet function during the 10 days before operation. All patients were premedicated with atropine 0.01mg/kg intramusclely 30 min before the operation. In the operation room, ketamine hydrochloride 2-4 mg/kg and midazolam 0.05-0.10mg/kg were intramusclely given. After the patients fell asleep, blood pressure(BP), pulse oxygen saturation (SpO₂) and electrocardiogram(ECG) were measured. After an arm vein was cannulated for intravenous transfusion, epidural anesthesia was done. After the success of the epidural catheter placement,1% lidocaine hydrochloride 8-10mg/kg were injected to epidural space through the catheter. Thromboxane B2(TXB2), alpha-granular membrane protein (GMP-140), platelet count(PLT),activating coagulation time(SonACT), clot rate and platelet function(PF) were measured at the following time point: pre-induction of anesthesia(T₁), just before skin incision(T₂), 1h after skin incision(T₃) and at the end of operation(T₄).Results: (1)There were no significant differences of age,sex ratio and weight between the two groups (P>0.05). See Table 1. (2) PLT in group B was significantly lower than that in A group(P<0.05). In both groups, there was no difference of PLT at T₁ and T₂(P>0.05); PLT at T₃ was significantly lower than that at T₁ and T₂; PLT at T₄ was significantly lower than that at T₁, T₂ and T₃(P<0.05). (3) TXB2 and GMP-140 in B group was significantly higher than group A at the four time point. In both groups, TXB2 and GMP-140 at T₂ was significantly lower than those at T₁; and TXB2 and GMP-140 at T₃ was significantly higher than those on T₂ ; T₄ was significantly higher than those at T₂, T₃ (P<0.05). (4) There was significant difference of SonACT,clot rate and PF at the four time point between the two groups. In group A, SonACT at T₃ was significantly longer than that at T₁, T₂; SonACT at T₄ was significantly longer than that at T₁, T₂, T₃. In group B , the SonACT at T₃,T₄ was significantly longer than that at T₁, T₂. In group A clot rate at T₃ was significantly lower than that at T₁, T₂; clot rate at T₄ was significantly lower than that at T₁, T₂, T₃. Clot rate in group B at T₃, T₄ was significantly lower than that at T₁,T₂. In both groups, PF at T₂ was significantly lower than that at T₁; PF at T₃ was significantly higher than that at T₂; the PF at T₄ was significantly higher than that at T₂, T₃(P<0.05).Conclusion: (1) After acute trauma, platelet count in children with minor trauma is increased, and is higher than that in children with severe trauma. (2) The activity of platelet in children increases after acute trauma and during operation. The platelet punction in children with severe trauma is higher than that with minor trauma.