Refrigerated platelets stored in whole blood up to 5 days adhere to thrombi formed during hemorrhagic hypotension in rats

Essentials In vivo function of platelets stored at various conditions was studied in normo- and hypotension. Refrigerated platelets stored up to 5 days performed as well as those stored at room temperature. Platelet adhesion and thrombus formation were higher in ruptured vessels of hemorrhaged animals. In vivo data suggest that refrigerated platelets are hemostatically effective during hypotension.

SUMMARY

Background There is renewed interest in the therapeutic use of cold-stored platelets for bleeding patients. However, critical information is absent or partially available in vitro. Therefore, thrombus formation and platelet adhesion were studied in vivo, in situ, using bleeding and thrombosis models in instrumented rats, and confocal intravital videomicroscopy. Objectives We tested the hypothesis that refrigerated (4 °C) platelets (stored for 24 h or 5 days) participated in thrombus formation as well as platelets stored at room temperature (RT, 22 °C). This hypothesis was tested in normovolemia and hemorrhagic hypotension. Methods & Results After fluorescently-labeled platelet infusion, endothelial injury and vessel rupture were laser-induced in cremaster microvessels and platelet adhesion in > 230 developing thrombi was evaluated. Blood samples were collected for biochemistry and coagulation assays while multiple systemic physiologic parameters were recorded. Hemorrhagic hypotension study animals were subjected to 40% hemorrhage, leading to hypotension and hemodilution, during in vivo platelet adhesion assessments. The fluorescence intensity associated with labeled platelet adherence provided a quantitative index of adhesion. Cold-stored platelets performed as well as those stored at RT in normovolemic animals. During hypotension, cold-stored platelets still performed as well as RT-stored platelets, whereas platelet adhesion and thrombus formation were increased relative to normovolemic animals, in bleeding model experiments. Conclusions We found the methodology suitable for evaluating platelet function in vivo after different storage conditions in fully monitored animals. Refrigerated platelets (stored up to 5 days) participated as well as RT-stored platelets in thrombi formed after hemorrhage, suggesting that refrigerated platelets are effective during hypotensive situations.

Morbidity of early spine surgery in the multiply injured patient

INTRODUCTION

The optimal timing of surgery for multiply injured patients with operative spinal injuries remains unknown. The purported benefits of early intervention must be weighed against the morbidity of surgery in the early post-injury period. The performance of spine surgery in the Afghanistan theater permits analysis of the morbidity of early surgery on military casualties. The objective is to compare surgical morbidity of early spinal surgery in multiply injured patients versus stable patients.

MATERIALS AND METHODS

Patients were retrospectively categorized as stable or borderline unstable depending on the presence of at least one of the following: ISS >40, ISS >20 and chest injury, exploratory laparotomy or thoracotomy, lactate >2.5 mEq/L, platelet <110,000/mm(3), or >10 U PRBCs transfused pre-operatively. Surgical morbidity, complications, and neurologic improvement between the two groups were compared retrospectively.

RESULTS

30 casualties underwent 31 spine surgeries during a 12-month period. 16 of 30 patients met criteria indicating a borderline unstable patient. Although there were no significant differences in the procedures performed for stable and borderline unstable patients as measured by the Surgical Invasiveness Index (7.5 vs. 6.9, p = 0.8), borderline unstable patients had significantly higher operative time (4.3 vs. 3.0 h, p = 0.01), blood loss (1,372 vs. 366 mL, p = 0.001), PRBCs transfused intra-op (3.88 vs. 0.14 U, p < 0.001), and total PRBCs transfused in theater (10.18 vs. 0.31 U, p < 0.001).

CONCLUSIONS

The results indicate that published criteria defining a borderline unstable patient may have a role in predicting increased morbidity of early spine surgery. The perceived benefits of early intervention should be weighed against the greater risks of performing extensive spinal surgeries on multiply injured patients in the early post-injury period, especially in the setting of combat trauma.

The chlorine controversy

Environmental groups have called for a phaseout of the use of chlorine in industrial chemistry on the grounds that such use inevitably leads to the production of persistent, bioaccumulative toxins. This policy prescription is based on an application of the Precautionary Principle which holds that industry should demonstrate that its products and processes are safe before allowing releases of product or waste into the environment. The chemical industry has rejected the call to phaseout chlorine, and claims that available data on either the environmental exposure pathways or the toxicology of chlorinated compounds are inadequate to support responsible decision-making. Industry leaders have called for environmental policy to be based on sound science, comparative risk assessment, and cost-benefit analysis. The controversy over chlorine shows that the U.S. environmental policy-making framework may no longer be capable of producing solutions to environmental problems that satisfy important constituencies within our society.