Massive blood transfusion in the elective surgical setting

Greater Sensitivity of Pigtailed Macaques (Macaca nemestrina) than Baboons to Total Body Irradiation

Two juvenile pigtailed macaques (animals 1 and 2) received total body irradiation (TBI) followed by autologous stem cell transplantation, by a procedure known to be well tolerated by baboons. In this procedure, the TBI consisted of treatment on two consecutive days with 255cGy on one side, followed after 1-2 min by a similar dose on the other side. The two pigtailed macaques showed rapid haematopoietic engraftment, but succumbed either to systemic cytomegalovirus (CMV) infection and necrotising colitis or to haemorrhagic cystitis and tubulointerstitial nephritis. For four further pigtailed macaques (animals 3-6) the radiation procedure was changed to four equal doses of 255cGy, given 6-12 h apart. Animals 4-6 all showed engraftment and survived for long periods (>218 days), with no, or only minor treatable, complications. Animal 3 failed to show engraftment and succumbed to radiation-induced vascular lesions and severe multiorgan haemorrhages. The results suggest that pigtailed macaques have a lower tolerance threshold than baboons, rhesus macaques or human beings to TBI, the adverse effects of TBI being indistinguishable from those seen in human patients. The results also suggest that a hyperfractionated radiation procedure can prevent radiation-induced morbidity and mortality in pigtailed macaques.

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management

PURPOSE

To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies.

METHODS

Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings.

PRINCIPAL FINDINGS

Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy.

CONCLUSIONS

Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

Recombinant activated factor VII for the treatment of life-threatening haemorrhage

To describe the use of recombinant activated factor VII (rFVIIa) in patients with life-threatening haemorrhage. We report a case series of Australian patients with life-threatening haemorrhage who were treated with rFVIIa prior to August 2002 namely 21 patients, median age 45 years (range 22-79 years), 33% (seven of 21) female. The major causes for bleeding were multi-trauma, cardiac or vascular surgery, or orthoptic liver transplantation. In the 24 h prior to the administration of rFVIIa, the median blood usage was 22 U packed cells (range 3-66 U), the median International Normalized Ratio was 1.6 (range 1.4-3.6) and the median activated partial thromboplastin time was 55 s (range 31-180 s). During the 24 h after administration of rFVIIa, the median blood usage was 2 U packed cells (range 0-16 U), the median International Normalized Ratio was 1.0 (range 0.9-1.2) and the median activated partial thromboplastin time was 40 s (range 30-94 s); P < 0.001 for each comparison. Sixteen of the 21 patients were discharged from hospital or were alive at 30 days. There were no thrombotic complications following the administration of rFVIIa. These uncontrolled data suggest a role for rFVIIa as an adjunctive haemostatic measure in surgical patients with life-threatening haemorrhage for whom conventional measures to achieve haemostasis have failed.