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Biomedical subjects

John R Hess

Publications and source records attributed to John R Hess.

At least 19 recordsLinked to original sources
PubMed2006

Indications for early fresh frozen plasma, cryoprecipitate, and platelet transfusion in trauma.

BACKGROUND: Massive blood transfusion can be lifesaving in the treatment of severe trauma. Guidelines for the use of non-RBC blood components in the early phase of trauma resuscitation are largely based on extensions of expert recommendations for general surgery. METHODS: The logic and evidence for the use of plasma, platelets, and cryoprecipitate early in the course of massive transfusion for trauma were reviewed. Large series of consecutive patients were sought. FINDINGS: Resuscitation of the most severely injured and massively hemorrhaging patients usually starts with crystalloid fluids and progresses to uncross-matched RBC. Low blood volume, insensible losses, consumption, and resuscitation with plasma poor RBC concentrates rapidly lead to plasma coagulation factor concentrations of less than 40%. This typically occurs before 10 U of RBC have been transfused. Early initiation of plasma therapy is often delayed by its lack of immediate availability in the trauma center. Platelets usually fall to concentrations of 50-100 x 10(9)/L after 10-20 units of RBC have been given, but platelet concentrations in individual patients are quite variable and can decrease more quickly. Ideal platelet concentrations in trauma patients are not known, but are generally held to be greater than 50 x 10(9)/L. Cryoprecipitate can rapidly increase the concentrations of fibrinogen and von Willebrand's factor, but the advantages of higher than normal concentrations are speculative. CONCLUSIONS: Early use of plasma and platelets at the upper end of recommended doses appears to reduce the incidence of coagulopathy in massively transfused individuals.

Blood Coagulation Disorders↗
PubMed2006

The coagulopathy of trauma versus disseminated intravascular coagulation.

The coagulopathy of trauma is a syndrome of non-surgical bleeding from mucosal lesions, serosal surfaces, and wound and vascular access sites associated with serious injury, hypothermia, acidosis, hemodilution, and occasionally with classic disseminated intravascular coagulation (DIC). It can be largely explained by the effects of cold on platelet function, the effect of pH on coagulation factor activity, and the dilutional effects of resuscitation fluids and conventional blood products. DIC occurs acutely after trauma when brain, fat, amniotic fluid, or other strong thromboplastins enter the circulation. It occurs subacutely when endothelial inflammation or failure reduces clearing of activated coagulation factors allowing microthrombi to cause secondary injury. The coagulopathy of trauma should be anticipated in massive transfusion situations. Early treatment with plasma can delay its onset. The underlying mechanisms should be confirmed with laboratory testing.

Blood Coagulation Disorders↗
PubMed2006

Massive transfusion practices around the globe and a suggestion for a common massive transfusion protocol.

BACKGROUND: Massive transfusion, the administration of 10 to more than 100 units of red blood cells (RBC) in less than 24 hours, can be a life saving therapy in the treatment of severe injury. The rapid administration of large numbers of RBC, along with sufficient plasma and platelets to treat or prevent coagulopathy, is frequently a disorderly process. Patient care and collaborative research might be aided with a common protocol. METHODS: The authors polled trauma organizations and trauma centers to find examples of massive transfusion protocols. The goals and ease of use of these protocols were evaluated. RESULTS: Massive transfusion protocols exist at a relatively small number of large and well-organized trauma centers. Most of these protocols are designed to treat pre-existing and/or ongoing coagulopathy. CONCLUSIONS: The evidence would suggest that prevention of coagulopathy is superior to its treatment. Simple ratios such as 1:1:1 RBC:plasma:platelets have the benefit of ease of use and the relatively higher plasma and platelet doses appear to be associated with improved outcome. Such a standard protocol can foster multicenter research on resuscitation and hemorrhage control. The fixed volume ratios might allow the number and rate of administered units of RBC to be used as surrogates for blood loss and primary treatment effect.

Australia↗
PubMed2006

Fresh whole blood transfusion: a controversial military practice.

The transfusion of fresh whole blood (FWB) for trauma-induced coagulopathy is unusual in civilian practice. However, US military physicians have used FWB in every combat operation since the practice was introduced in World War I and continue to do so during current military operations. We discuss our review of all blood products administered to US military casualties in Operation Iraqi Freedom (OIF) between March and December 2003. FWB transfusions were most frequent when demands for massive transfusions wiped out existing blood supplies. FWB patients had the highest blood product requirements; however, mortality did not differ significantly between FWB and non-FWB patients overall or for massively transfused patients. We review the current military practice of FWB transfusion in combat theaters and conclude that FWB transfusion is convenient, safe, and effective in certain military situations.

Blood Coagulation Disorders↗
PubMed2005

Optimizing the use of blood products in trauma care.

Blood transfusion has been used to treat the injured since the US Civil War. Now, it saves the lives of tens of thousands of injured patients each year. However, not everyone who receives blood benefits, and some recipients are injured by the transfusion itself. Effective blood therapy in trauma management requires an integration of information from diverse sources, including data relating to trauma and blood use epidemiology, medical systems management, and clinical care. Issues of current clinical concern in highly developed trauma systems include how to manage massive transfusion events, how to limit blood use and so minimize exposure to transfusion risks, how to integrate new hemorrhage control modalities, and how to deal with blood shortages. Less developed trauma systems are primarily concerned with speeding transport to specialized facilities and assembling trauma center resources. This article reviews the factors that effect blood use in urgent trauma care.

Adult↗
PubMed2005

Putting the pieces together: Roger I. Lee and modern transfusion medicine.

Roger Irving Lee (1881-1964) played significant scientific and leadership roles in overcoming the clinical impediments to blood transfusion in the 1910s. He developed the first successful anticoagulant system, paraffinized glass, and the first sterile system for indirect transfusion without defibrination, the Lee-Vincent flask. He used citrate as an anticoagulant before those generally credited with its discovery did. He introduced surgical antisepsis of the donor site and a practical system for maintaining typed blood for a large hospital donor and transfusion service. He was Oswald Robertson's mentor at Harvard as well as his commanding officer in the Harvard Medical Unit on the Western Front during World War I. Lee sent Robertson to perform "his preserved blood cells transfusion" in the casualty clearing stations of the British Third Army and provided Robertson's group with O donors, enabling the most important medical development of the war. Lee put the pieces of modern blood banking and transfusion together.

Anticoagulants↗
PubMed2005

Who needs blood?

Explore the source record for details and available documents.

APACHE↗
PubMed2005

Massive blood transfusion for trauma.

PURPOSE OF REVIEW: Massive blood transfusion saves the lives of thousands of severely injured patients each year, but it does so in the context of the evolving epidemiology of injury, of trauma centers and trauma systems, and of blood safety and new technologies for hemorrhage control. This article reviews recent knowledge and advances that impact on the use and effectiveness of massive transfusion. RECENT FINDINGS: Injury is rapidly becoming the second leading cause of death in the world. These deaths are highly preventable with social and engineering controls and good trauma care. Massive transfusion is readily available, safe, effective, and cheap in the context of modern trauma center care. However, aged blood products can cause transfusion-related acute lung injury, and better blood storage systems are under development. Recent work has improved understanding of the coagulopathy associated with acidosis and provided guidance for limiting dilutional coagulopathy. Nevertheless, massive transfusion always leads to coagulopathy and so is at best an adjunct to good surgical care. Better drugs and devices for hemorrhage control, such as recombinant activated factor VII and hemostatic bandages, are in development. SUMMARY: Injury is a major public health and medical system problem. Progress in basic science, clinical care, and the development of better hemorrhage control devices are all improving outcome for massively transfused patients. Investment in trauma care and supporting blood supply systems is highly cost effective.

Blood Transfusion↗
PubMed2004

Factor VIIa for correction of traumatic coagulopathy.

INTRODUCTION: Activated factor VIIa (FVIIa) was developed to treat hemophiliacs with high-titer antibodies to factor VIII. FVIIa initiates thrombin formation by binding with exposed tissue factor. Anecdotal reports have described the utility of FVIIa in correcting coagulopathy from trauma, but no large series exists. We present our experience with 81 coagulopathic trauma patients treated using FVIIa in years 2001-2003, compared with "control" patients matched from the trauma registry from the same time period. METHODS: Use of FVIIa was restricted to active hemorrhage with clinical coagulopathy. We recorded the cause of coagulopathy, dose of FVIIa administered, effect on clinical coagulation, pertinent laboratory values, length of stay, number and type of blood products administered, and patient outcome. For the same time period we also examined outcomes in coagulopathic patients who did not receive FVIIa. RESULTS: Causes of coagulopathy were diverse, and included acute traumatic hemorrhage (46 patients), traumatic brain injury (20), warfarin use (9), congenital Factor VII deficiency (2), and other acquired hematologic defects (4). Coagulopathy was reversed in 61/81 cases (75%), with an associated reduction in PT from 19.6 to 10.8 (p=0.000018). 34 patients (42%) survived to hospital discharge (20/46 traumatic hemorrhage, 5/20 TBI, 4/9 on warfarin, 2/2 factor deficient, 3/4 other). Patients died from irreversible shock, multiple organ system failure, or traumatic brain injury. FVIIa patients had a higher mortality than coagulopathic controls matched by specific anatomic injuries, admission lactate value, and predicted probability of survival. Only a group identified by all three characteristics had a similar mortality to the FVIIa cohort, but the number of patients that could be matched this way was too small to be meaningful. CONCLUSION: FVIIa therapy lead to an immediate reduction in coagulopathic hemorrhage in most cases, accompanied by a significant improvement in laboratory measures. Application of FVIIa as a therapy of last resort makes the identification of equivalent control patients difficult. Use of FVIIa should be considered for any patient with coagulopathic hemorrhage in which surgically-accessible bleeding has been controlled. Prospective trials of FVIIa in patients with traumatic coagulopathy are strongly indicated, and should focus on appropriate patient selection and the dose and timing of therapy.

Adolescent↗
PubMed2004

Red cell freezing and its impact on the supply chain.

Red blood cells (RBC) can be frozen in glycerol solutions and stored for many years. Thawed RBC must have the glycerol removed, but the recovered cells have normal survival in humans. Freezing has been used to store RBC of rare phenotypes for more than 40 years. In the 1960s and 1970s, when medical technology and blood use were expanding rapidly and liquid whole blood and RBC storage were limited to 3 weeks, many attempts were made to expand the use of frozen RBC for meeting the needs for a stable blood supply and to have RBC reserves for emergencies. These attempts have largely been abandoned because of the cost of freezing, storing and processing, better management of the larger and longer lived RBC inventory, concerns about the safety of stored RBC that have not received the most up-to-date testing and the losses associated with the short shelf life of thawed RBC. New automated frozen RBC processing systems will potentially allow extending the outdate of thawed RBC to 2 weeks, but will not materially effect the costs or losses associated with the use of frozen RBC. RBC freezing will have little effect on the logistics of blood supply.

Blood Banks↗
PubMed2004

Blood transfusion rates in the care of acute trauma.

BACKGROUND: Ten to 15 percent of all RBCs are used in the care of injury. Understanding patterns of RBC use is important. Routine resource allocation, planning for mass casualty situations, designing research, and optimizing triage all can be usefully informed. STUDY DESIGN AND METHODS: Blood Bank and Trauma Registry records were linked to produce a transfused blood product list for each patient directly admitted from the scene of injury to a large Level 1 trauma center in calendar year 2000. Categorical associations between demographic data, Injury Severity Score, transfused products, and outcome were sought. Special attention was paid to the groups receiving uncross-matched RBCs and more than 10 units of RBCs. RESULTS: Eight percent (479/5645) of acute trauma patients received RBCs, using 5219 units and sustaining an overall mortality of 27 percent. Sixty-two percent of RBCs were given in the first 24 hours of care. Three percent of patients (147 injured) received more than 10 units and received 71 percent of all RBCs given. Mortality in this cohort was 39 percent. Ninety percent of the patients who received more than 10 units of RBCs received plasma, and 71 percent received PLTs. CONCLUSIONS: A small number of patients receives most of the blood products used in the treatment of injury. Transfusion of more than 10 units of RBCs identifies a subgroup where most patients received plasma and PLTs to treat actual or anticipated dilutional coagulopathy. There is no clear threshold beyond which blood use is futile.

Acute Disease↗
PubMed2003

Treating coagulopathy in trauma patients.

Coagulopathy in patients with severe trauma is related to platelet and coagulation factor loss, consumption, and dysfunction. It is exacerbated by dilution, acidosis, and hypothermia. Hemorrhage control, warming, and appropriate blood product support are lifesaving. Further improvements in hemorrhage control will save additional lives and resources.

Acidosis↗
PubMed2003

Recombinant factor VIIa for control of hemorrhage: early experience in critically ill trauma patients.

STUDY OBJECTIVE: To examine our institutional experience with recombinant Factor VIIa (rFVIIa) as a treatment for exsanguinating hemorrhage in critically ill trauma patients. DESIGN: Retrospective case review. SETTING: A specialized trauma and critical care hospital, serving as the quaternary referral center for trauma and surgical shock in the state of Maryland. PATIENTS: All patients with diffuse coagulopathy and impending exsanguination, given rFVIIa in an effort to control life-threatening hemorrhage. Patients were in the intensive care unit (ICU) or operating room (OR) and included both acute admissions and late-stage patients with multiple organ system failure. INTERVENTIONS: Patients of interest were those that had received rFVIIa. MEASUREMENTS: Examination of medical records, including pharmacy data, laboratory results, and the institutional trauma registry. MAIN RESULTS: Administration of rFVIIa contributed to successful control of hemorrhage in three of five patients. Failure in two patients was mostly likely due to overwhelming shock and acidosis. CONCLUSIONS: Administration of rFVIIa shows promise in the treatment of exsanguinating hemorrhage. Prospective, controlled clinical trials of this therapy are strongly recommended.

Abdominal Injuries↗