Platelet transfusion: a clinical practice guideline from the AABB

BACKGROUND: The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients. METHODS: These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. RECOMMENDATION 1: The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 2: The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence). RECOMMENDATION 3: The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 4: The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 5: The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 6: The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).(AU)

Preinjury warfarin does not impact outcome in trauma patients.

OBJECTIVE: The objective of this study was to determine whether the preinjury condition of anticoagulation had an adverse impact on patients sustaining injury. METHODS: A retrospective analysis was performed for prospectively collected registry data from 1995-2000 from all accredited trauma centers in Pennsylvania. The registry was queried for all trauma patients who had anticoagulation therapy as a preinjury condition (PIC). This group served as our experimental cohort. A control cohort (not having warfarin therapy as a PIC) was developed using case-matching techniques for age, sex, Glasgow Coma Scale (GCS), Injury Severity Score (ISS), A Severity Characterization of Trauma (ASCOT) score, and in the head injured patients, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnoses. Head and non-head injured patients were evaluated separately. The cohorts were examined for 28-day mortality, intensive care unit length of stay (ICU-LOS), hospital length of stay (HOS-LOS), PICs, occurrences, discharge destinations, and functional status at discharge. Chi2 and Student's t test were used to evaluate the data; p values < 0.05 were considered significant. RESULTS: Two thousand nine hundred forty-two patients were available for analysis. The prevalence of PICs was significantly greater in the warfarin group for both the head and non-head injured populations (p < 0.003 and p < 0.0001, respectively). The incidence of occurrences in the non-head injured population was statistically higher for the warfarin patients (p < 0.001), but showed no difference in the head injured group regardless of warfarin use (p = 0.15). Functional status at discharge demonstrated no clinically significant difference between the warfarin and non-warfarin groups in both head and non-head injured populations. There was no difference in discharge destination in the head injured population; however, in the non-head injured population a greater percentage of non-warfarin patients was discharged to home when compared with the warfarin patients. CONCLUSION: Our data suggest that the PIC of anticoagulation with warfarin does not adversely impact mortality or LOS outcomes in both head and non-head injured patients. In non-head injured patients, however, the occurrence rates and discharge destination were different. More research needs to be done to determine whether this is related to anticoagulation or other reasons (i.e., number of PICs). These data should be used when weighing risk/benefit ratios of prescribing chronic anticoagulation.

Long-term follow-up of trauma patients with a vena caval filter.

BACKGROUND: Venous thromboembolism (VTE) is an important complication in blunt trauma patients. At our Level I trauma center, we had a deep venous thrombosis (DVT) rate of 3.2% from 1993 to 1997 despite an aggressive VTE prophylaxis program. During this time period, we placed vena caval filters (VCF) for both traditional and prophylactic indications. This project was developed to establish a VCF registry for trauma patients to determine the long-term complications of VCF placement. METHODS: A letter was sent to all trauma patients who had a VCF placed from 1993 through 1997. Patients were asked to return for a history and physical examination to detect signs and symptoms related to VTE, a duplex ultrasound of the inferior vena cava, and a plain abdominal radiograph to determine filter migration. RESULTS: There were 191 VCFs inserted in our trauma population from 1993 to 1997. There were 105 patients (75 male and 30 female) available for evaluation, with a mean follow-up of 28.9 months. Forty-one VCFs were placed in patients with DVT or pulmonary embolism, and 64 were placed in patients for prophylactic indications as per the guidelines developed by the Eastern Association for the Surgery of Trauma. There were no clinically identifiable complications related to insertion of the VCF. There were no pulmonary embolisms detected after VCF insertion. In follow-up, only one filter (0.95%) migrated, and this was minimal (1 cm cephalad). One (0.95%) vena cava was occluded, based on duplex ultrasonography, and 11 patients (10.4%) had signs or symptoms of leg swelling after hospital discharge. Twenty eight (44%) of the 64 patients with prophylactic VCFs developed a DVT after filter placement. CONCLUSION: VCFs placed in trauma patients have acceptable short- and long-term complication rates. Consideration should be given to prophylactic VCF placement in patients at high risk for VTE. Randomized controlled trials are needed to evaluate whether VCF insertion increases the risk for subsequent DVT.

Impact of preinjury warfarin use in elderly trauma patients.

BACKGROUND: This study examined the hypothesis that elderly trauma patients on warfarin before injury will have increased morbidity and mortality compared with elderly trauma patients not on warfarin. METHODS: From 1993 to 1995, trauma patients were grouped by age and presence or absence of warfarin use before injury. Groups were analyzed with respect to Injury Severity Score, Trauma Registry and Injury Severity Score, Glasgow Coma Scale score, Intensive Care Unit days, hospital days, units of blood transfused, and mortality rates. Statistical analysis was completed by using the Student's t test. RESULTS: Records of 61 patients administered warfarin and 800 patients not administered warfarin were available for analysis. There were no statistically significant differences between patients on prehospital warfarin and those not on prehospital warfarin. CONCLUSION: This study indicates that elderly trauma patients on warfarin before injury do not have increased morbidity and mortality compared with elderly trauma patients not on warfarin.

Small-bowel and mesentery injuries in blunt trauma.

BACKGROUND: The purpose of this study was to identify factors that would aid in the diagnosis of small-bowel and mesentery injuries (SBMI) in blunt trauma patients. METHODS: Retrospective review of 15,779 blunt trauma patients admitted to a Level I trauma center between January 1991 and December 1996. RESULTS: A total of 5,303 patients sustained abdominal injuries, 70 of whom had more than 111 SBMI. Seventy-nine percent were victims of motor vehicle collisions. Thirty patients had isolated SBMI and 40 had associated intra-abdominal injuries. Twelve patients arrived with systolic blood pressure < 90 mm Hg, eight of whom died. Mean base deficit was -7.3 +/- 6.3 in 52 patients who had arterial blood gases determined. Fifty-three of 60 patients had hematuria. Sixty-seven patients required laparotomy. Delayed exploration occurred in 15 patients who underwent initial computed tomography but had subsequent changes in physical status. Two of 20 patients had negative diagnostic peritoneal lavage on admission and were eventually explored based on abdominal computed tomographic findings and changes in physical examination. There were 15 deaths. Delay in diagnosis (>12 hours after arrival) occurred in nine patients with no deaths or significant morbidities. Mean Injury Severity Score was 29 +/- 16.7: 43 +/- 17 in nonsurvivors and 25 +/- 14.3 in survivors (p < 0.05). CONCLUSION: The diagnosis of SBMI is often made in the presence of associated intra-abdominal injuries. Isolated SBMI are common, however, and special attention to the mechanism of injury, abdominal examination, presence of hematuria, and significant base deficit should raise suspicion to the possibility of SBMI. Findings on abdominal computed tomography that may suggest SBMI and should prompt further evaluation include free fluid, thickened bowel, and extraluminal air. Because delay in diagnosis does not seem to affect morbidity or mortality, dedication to observation and serial physical examinations will aid in the proper identification of elusive SBMI. Mortality, however, does appear to be related to the presence of hypotension on admission and associated injuries.

Utility of chest radiographs after guidewire exchanges of central venous catheters.

OBJECTIVE: To determine whether chest radiographs are warranted after uncomplicated guidewire exchanges of central venous catheters in patients admitted to a Level I trauma intensive care unit. DESIGN: Prospective study performed in two phases. SETTING: Intensive care unit in a Level I trauma center. PATIENTS: Patients admitted to a Level I trauma center intensive care unit who required central venous catheter guidewire exchanges. INTERVENTIONS: Criteria for uncomplicated guidewire exchanges were established and followed. A catheter exchange checklist was completed at each procedure, and a chest radiograph was performed after each guidewire exchange. The complications followed were catheter malposition, pneumothorax, hemothorax, and cardiac tamponade. Results were reviewed after 3 mos, and a second phase of the study was initiated in which chest radiographs were obtained selectively and were not performed for uncomplicated exchanges. If obtained, subsequent radiographs were reviewed, and patients were followed to discharge for complications. MEASUREMENTS AND MAIN RESULTS: One hundred central venous catheter exchanges with postprocedure radiographs were evaluated in phase I. The only complication identified was one malpositioned catheter. In phase II, 110 patients were followed. Eighty-four patients did not have chest radiographs performed after guidewire exchange; 69 patients had subsequent radiographs documenting good placement of the catheter, and 15 patients did not have a radiograph before death (n = 2) or discharge from the hospital (n = 13). Sixteen patients had postprocedure radiographs performed. There were no malpositioned catheters or complications related to guidewire exchanges. CONCLUSIONS: Chest radiographs are unwarranted after uncomplicated guidewire exchanges of central venous catheters in hemodynamically stable, monitored patients. Eliminating these radiographs will result in significant cost and time savings without adversely affecting patient outcome.

Outcome of blunt thoracic aortic injury in a level I trauma center: an 8-year review.

BACKGROUND: The purpose of this study was to evaluate our experience with blunt thoracic aortic injury and identify factors predictive of outcome. METHODS: Hospital charts, trauma registry data, and autopsies of 64 patients with blunt thoracic aortic injury from 1988 to 1995 were reviewed. RESULTS: Patients were identified and segregated based on admission physiology. Group 1 patients (n = 19) arrived in arrest. Group 2 patients (n = 10) arrived in shock with systolic BP 90. Group 3 patients (n = 35) arrived with systolic BP>90. All patients in groups 1 and 2 expired. Injury Severity Scores for nonsurvivors in group 3 (n = 12) were significantly higher than survivors. There were no significant differences when comparing time of injury to repair or arrival between groups, or in mortality or paralysis comparing repair techniques or clamp/bypass times. Double lumen endotracheal tubes caused significant operative delays compared to single lumen tubes. CONCLUSIONS: Predictors of survivability were hemodynamic stability on arrival and lower Injury Severity Scores. In thoracic aortic injury patients arriving hemodynamically stable, Injury Severity Score correlated with mortality but not paralysis.

Posttrauma thromboembolism prophylaxis.

PURPOSE: The need to study methods of thromboembolism prophylaxis in high-risk trauma patients is well established. The purpose of this study was to evaluate the feasibility of a proposed study design, including current methods of prophylaxis, performance of a risk assessment profile scale, and the use of serial color-flow duplex studies in detecting deep venous thrombosis (DVT). METHODS: Patients were enrolled into the study, stratified as to their ability to receive anticoagulation and randomized to low-dose unfractionated heparin, low molecular weight heparin, pneumatic compression devices, or foot pumps with or without vena caval filters. Serial ultrasound scans were performed at designated intervals for 4 weeks. Pulmonary angiograms were obtained for clinical signs or symptoms of pulmonary embolism. RESULTS: Fifty-three patients, 32 male and 21 female patients with a mean age of 44 years, completed the study. The incidence of DVT was 43% (23 of 53 patients) and significantly higher in older patients. There were no pulmonary embolisms. Color-flow duplex proved to be a sensitive method for detecting both proximal and distal thrombi. The risk assessment profile for thromboembolism (RAPT) scale identified a group of patients with a high incidence of DVT. However, the occurrence of DVT was not correlated with the magnitude of the RAPT score. CONCLUSION: The ability to identify a population with a high incidence of thromboembolism by using the RAPT score to detect asymptomatic DVT, and the suggested advantage of low molecular weight heparin, all support the need for an appropriately powered randomized clinical trial.

Defining "dead on arrival": impact on a level I trauma center.

OBJECTIVE: To determine the potential impact of defining criteria for "dead on arrival" (DOA) on a Level I trauma center. METHODS: From 1990 to 1994, trauma patients having cardiopulmonary resuscitation (CPR) performed by certified prehospital personnel were reviewed for time of CPR, outcome, and costs to determine whether any benefit would have been realized had DOA criteria been followed. RESULTS: A total of 106 patients had prehospital CPR; 20 did not meet DOA criteria and underwent resuscitation, three survived (15%). Eighty-six patients met DOA criteria; 16 were pronounced dead without further resuscitative efforts (in-hospital costs of $200/patient), while 70 (81%) had continued resuscitation with no survivors (in-hospital costs of $4150/patient). The positive predictive value for criteria was 100%. Had criteria been implemented, total cost savings over the 5-year period would have been $290,000. CONCLUSIONS: National DOA criteria could dramatically reduce the burden on trauma centers with an estimated minimum annual savings of $14 million.

Early inflammatory response correlates with the severity of injury.

OBJECTIVE: To determine if the early inflammatory response correlates with the severity of injury in a blunt trauma model in rats. DESIGN: Prospective, randomized, controlled trial. SETTING: Research laboratory. SUBJECTS: Male Sprague-Dawley rats, weighing 250 to 400 g. INTERVENTIONS: Twenty-two male Sprague-Dawley rats were divided randomly into single hindlimb fracture, bilateral hindlimb fracture, and no fracture groups. At 90 mins, all animals underwent midline laparotomy and aspiration of blood from the inferior vena cava. Venous blood gas, plasma lactate, and plasma concentrations of tumor necrosis factor (TNF), prostaglandin F(6-keto-PGF1 alpha), and interleukin (IL)-6 were sampled. Statistical analysis was done via one-way analysis of variance and Scheffé post hoc analysis. In a second part of this experiment, the effect of hemorrhage on the release of IL-6 was evaluated. Animals in this group were compared with control and bilateral hindlimb fracture animals, using the Student's t-test. MEASUREMENTS AND MAIN RESULTS: There were no significant differences in venous pH or base deficit among the groups. Oxygen saturation was significantly decreased in the bilateral hindlimb fracture group when compared with the control group. In the hemorrhage plus bilateral fracture group, oxygen saturation was significantly decreased when compared with the bilateral fracture group. lactate concentrations in plasma were increased in both fracture groups as well as the hemorrhaged groups. Plasma TNF concentrations were increased in the injured groups but there was no significant difference between single and bilateral hindlimb fracture groups. The 6-keto-PGF1 alpha concentrations were increased in both of the fracture groups when compared with the control group and there was a significant difference between single and bilateral hindlimb fracture groups. Similarly, circulating IL-6 concentrations were significantly higher in the bilateral fracture group than in the single fracture group; both fracture groups were significantly higher than the control group. Hemorrhaged animals had even higher IL-6 concentrations. CONCLUSIONS: Plasma lactate and TNF concentrations were affected by injury, however their concentrations did not correlate with degree of injury. IL-6 concentrations were increased early postinjury and correlated with severity of injury. The 6-keto-PGF1 alpha concentrations in plasma also correlated with the severity of injury and this phenomenon may represent early endothelial activation which may be the source of IL-6 release.

Blunt injury augments interleukin-6 but not tumor necrosis factor in isolated, perfused rat hindlimbs.

An isolated, perfused hindlimb model in rats was used to examine the immediate inflammatory response after blunt tissue injury. A femur-fracture degloving model was used in isolated rat hindlimbs perfused with a modified Kreb's buffer (pH 7.4) containing albumin, washed human red blood cells (RBCs), amino acids, and glucose at 37 degrees C. Arterial and venous perfusate was sampled at 5, 20, and 80 minutes of perfusion. Initial experiments were conducted in perfusate void of white blood cells (WBCs), group 1 (-inj/-WBC, n = 6) and group 2 (+inj/-WBC). Subsequent experiments were conducted in perfusate containing activated WBCs, group 3 (-inj/+WBC, n = 6) and group 4 (+inj/+WBC, n = 7). Hindlimb muscle was analyzed for adenylate energy charge (EC) and lactate-to-pyruvate ratios (LPR) at the end of each perfusion. This preparation appeared metabolically stable in that oxygen consumption and lactate remained stable during the 80-minute perfusion and muscle EC and LPR indicated aerobic metabolism. Tumor necrosis factor (TNF) and thromboxane B2 (TXB2) were measured in all four groups while prostaglandin F (PGF1 alpha), IL-6, myeloperoxidase, and 8-isoprostane were measured in groups 3 and 4. Initial perfusions in the -WBC hindlimbs indicated no change in TNF release after injury. The TXB2 level increased during perfusion irrespective of injury. The PGF1 alpha was elevated at 80 minutes in both groups 3 and 4, however at 20 minutes PGF1 alpha levels were higher in group 4 compared with group 3. Interestingly, the IL-6 level was significantly elevated at 80 minutes in group 4 but not in group 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Secondary organ dysfunction. From clinical perspectives to molecular mediators.

The systemic inflammatory response and progression to secondary organ dysfunction are manifestations of the host's responses to injury. This article outlines the clinical manifestations of this injury-response cascade. The potential roles of cytokines, eicosanoids, platelet-activating factor, nitric oxide, oxygen-free radicals, and the leukocyte-endothelial interaction are explored in some detail. A goal-directed therapy of source control, resuscitation, and metabolic support is reviewed, and new therapies with monoclonal antibodies and immunomodulated nutrition are described. These new therapies hold great potential for finally improving the outcome of this fatal syndrome.

Effect of autonomic agents on renin release in the turtle, Pseudemys scripta.

Experiments were conducted in the freshwater turtle, Pseudemys scripta, to study the effect of autonomic agents on the control of renin in this primitive species. The unique finding in these studies was that, unlike mammals, isoproterenol infusion fails to increase renin activity even though heart rate and arterial pressure patterns indicated that systemic responses were similar to that in mammals. On the other hand, acetylcholine (ACh) infusion resulted in a prompt threefold elevation (P less than 0.01) of renin activity. This response was blocked by propranolol but not atropine. Other experiments demonstrated that ACh elicited a prompt elevation of circulating norepinephrine and epinephrine in these turtles and led to the hypothesis that the renin response to ACh was secondary to the release of endogenous catecholamines. This hypothesis was supported by the fact that, in reserpinized turtles, ACh failed to elicit the usual renin response. Further evidence stemmed from the fact that epinephrine administration led to a prompt fourfold increase (P less than 0.01) in renin, which could be blocked by propranolol. On the other hand, phenoxybenzamine failed to block the response under identical conditions. Taken as a whole, these data suggest that in this primitive species renin activity is elevated by endogenous catecholamines even though isoproterenol, a classical beta-adrenergic agonist, is without effect. These data illustrate again the need for caution when assuming analogy when comparing responses in primitive species with that of mammals.

Renin release in turtles: effects of volume depletion and furosemide administration.

To gain insight into the phylogenetic history of mechanisms controlling renin release, we conducted studies in the freshwater turtle Pseudemys scripta. Maneuvers known to stimulate renin release in mammals were evoked in the turtle, and the response was compared with that in mammals. Cumulative hemorrhage (30% blood vol) in anesthetized turtles failed to increase renin even though arterial pressure was reduced to 50% of control. An even more severe hemorrhage (60% blood loss) or hypotension induced by nitroprusside infusion in unanesthetized turtles also failed to evoke an enhanced level of renin. However, under identical experimental conditions, a 15% blood loss in rats increased renin at least fourfold (P less than 0.01). In other studies 48 h of furosemide administration in awake turtles increased renin more than threefold (P less than 0.05) and were accompanied by concomitant reductions in plasma sodium and potassium (P less than 0.05). The general conclusions drawn from these studies is that renin secretion in this primitive vertebrate is similar to that in mammals with respect to renal tubular and electrolyte mechanisms, but unlike all mammals tested these turtles do not possess an intrarenal baroreceptor component in renin control.

Characterization of the renin-angiotensin system in the turtle Pseudemys scripta.

Studies were conducted in freshwater turtles Pseudemys scripta to define some characteristics of the renin-angiotensin system in this reptile. Dialyzed acid-treated kidney extract (1 g tissue per ml water) produced a prolonged pressor response in unanesthetized turtles, which was eliminated by boiling the extract or by pretreating the turtle with [Sar1, Ile8]angiotensin II. A rat pressor assay was employed because turtle angiotensin (ANG) was bound poorly by the anti-[Asp1, Ile5, His9]ANG I used in our radioimmunoassay. Kidney extract incubated with homologous plasma (pH 5.5 and 25 degrees C) produced a time-dependent pressor response in rats. The pressor activity of the product was eliminated by dialysis or by pretreating the rats with [Sar1, Ile8]ANG II. The pressor response in anesthetized turtles to ANG I was significantly reduced by captopril, whereas the ANG II response remained unchanged, thus demonstrating the presence of ANG-converting enzyme activity in these animals. We determined the velocity of turtle ANG formation at various dilutions of enzyme (kidney extract) or substrate (plasma). Turtle kidney extract incubated with homologous plasma displayed typical Michaelis-Menten kinetics. Finally we conducted experiments to determine whether a portion of turtle plasma renin exists in an inactive form. Trypsinization caused a slight increase in plasma renin activity (PRA), whereas acidification to pH 3.3 yielded a fourfold increase in PRA.

Characterization of angiotensin pressor responses in the turtle Pseudemys scripta.

Studies were conducted in turtles (Pseudemys scripta) to characterize vascular responses to administration of exogenous angiotensin [Asp1-Ile5]angiotensin II (AII). Marked pressor responses were present following AII administration (2 microgram/kg iv). The pressor response was completely blocked by concomitant administration of an analogue of AII, [Sar1-Ile8]AII. Both alpha-receptor blockade with phenoxybenzamine or catecholamine depletion by reserpine administration reduced the pressor response approximately 50%. Further treatment with [Sar1-Ile8]AII completely blocked the AII pressor response. We conclude that the pressor response to AII in this species that represents an ancient group of reptiles includes a catecholamine-dependent component and direct vascular receptors, both of which are sensitive to AII.