Gerhardt Konig

Topical tranexamic acid reduces blood loss and transfusion rates in total hip and total knee arthroplasty

The objective of this study was to determine if tranexamic acid (TXA) applied topically reduced postoperative bleeding and transfusion rates after primary total hip arthroplasty (THA) and primary total knee arthroplasty (TKA). Two hundred and ninety consecutive patients from a single surgeon were enrolled. In TKA, TXA solution was injected into the knee after closure of the arthrotomy. In THA, the joint was bathed in TXA solution at three points during the procedure. In both THA and TKA the TXA solution was at a concentration of 3 g TXA per 100 mL saline. The mean blood loss was significantly higher in the non-TXA patients in both TKA and THA groups. Postoperative transfusions decreased dramatically with TXA, dropping from 10% to 0%, and from 15% to 1%, in the TKA and THA groups, respectively. Topical application of TXA significantly reduces postoperative blood loss and transfusion risk in TKA and THA.

Pharmacomechanical thrombectomy for iliofemoral deep vein thrombosis: An alternative in patients with contraindications to thrombolysis

OBJECTIVE Venous lysis is usually reserved for symptomatic patients with acute deep vein thrombosis (DVT) and low risk for bleeding. This study reports the use of pharmacomechanical thrombectomy (PMT) in patients with contraindications to thrombolysis. METHODS A retrospective review of all patients with symptomatic DVT treated between 2007 and 2008 with PMT was performed. All patients were treated by a combination of local tissue plasminogen activator (tPA) with the Angiojet (Possis Medical, Minneapolis, Minn) or Trellis device (Bacchus Vascular, Santa Clara, Calif). Catheter-directed lysis was used sparingly. RESULTS Forty-three patients (mean age, 48.4 +/- 16.6 years) presented with symptoms averaging 13.6 +/- 9.6 days in duration. Nineteen (44%) had symptoms for >14 days, and 15 (35%) had a high risk for bleeding. Symptomatic subclavian thrombosis occurred in eight (19%), and 35 (81%) presented with disabling lower extremity DVT (4 phlegmasia) despite anticoagulation. Fifteen patients had a thrombosed indwelling permanent filter. Sixty-three percent were treated in one session, but 16 patients required a lytic infusion after suboptimal PMT. Iliac stenting was required in 35% of limbs treated. Successful lysis (>50%) was achieved in 95% of patients and symptom resolution in 93%. All patients became ambulatory with no or minimal limitation. There were no major systemic bleeding complications, but access site hematoma occurred in two patients and worsening of pre-existing rectus sheath hematoma requiring transfusion occurred in another two. Limb salvage was maintained in 100% of patients who presented with phlegmasia. Mean follow-up was 5.0 +/- 4.8 months. Freedom from DVT recurrence and reintervention was 95% at 9 months by life-table analysis. CONCLUSIONS PMT can be safely and effectively used for subacute iliocaval and iliofemoral DVT and in patients with contraindications for lytic therapy, resulting in improved functional outcomes relative to their debilitated state before the procedure.

Treatment strategies of arterial steal after arteriovenous access

INTRODUCTION Ischemic steal syndrome (ISS) associated with arteriovenous (AV) access is rare but can result in severe complications. Multiple techniques have been described to treat ISS with varying degrees of success. This study compares the management and success associated with these techniques. METHODS Patients with ISS between June 2003 and June of 2008 at the University of Pittsburgh Medical Center were retrospectively reviewed. Demographics, type of AV access, management technique, and success of intervention were recorded. Success was defined as resolution of ISS symptoms while preserving access function. One hundred consecutive AV access procedures were reviewed for comparison. Data were analyzed using χ(2) test, Fishers exact test, and Students t test. The study was approved by our institutional review board. RESULTS A total of 114 patients with ISS had a mean age of 65 years (range, 20-90 years), were predominantly female (66%), diabetic (61%), and with a brachial origin fistula (69%). Risk factors for ISS included coronary artery disease (CAD; P < .001), hypertension (P < .001), and tobacco use (P = .048). Women were noted to have a brachial origin access more frequently than men (odds ratio [OR], 3.1; P = .009). Forty-four patients with mild steal were observed. Seventy patients underwent 87 procedures. Procedures performed included ligation (n = 27), banding (n = 22), distal revascularization and interval ligation (DRIL; n = 21), improvement of proximal inflow (n = 9), revision using distal inflow (RUDI; n = 4), and proximalization of arterial inflow (PAI; n = 3). Early procedures (<30 days from the index fistula) were mostly ligation (50%) or banding (38%), while DRIL was the most frequent choice for late interventions (41%). Banding had a high failure rate (62%) and was the most common reason for reintervention (8 of 11, 73%) and DRIL had a better success rate than banding (P ≤ .05). In our current practice, 18% of patients had an AV fistula with the proximal radial artery (PRA) as the inflow source, while this type of fistula accounted for only 2% of all ISS patients. Ligation resolved symptoms in all patients, but the AV access was lost. CONCLUSIONS Risk factors for development of ISS include CAD, diabetes, female gender, hypertension, and tobacco use. Among various options to treat ISS, banding has a low success rate and high likelihood for reintervention, while DRIL is particularly effective although not uniformly. Less invasive treatment options such as RUDI and PAI may be quite effective in treating ISS. Use of the PRA as the inflow source may decrease the incidence of ISS.

In vitro evaluation of a novel system for monitoring surgical hemoglobin loss

BACKGROUND:Accurate measurement of intraoperative blood loss is an important clinical variable in managing fluid resuscitation and avoiding unnecessary transfusion of blood products. In this study, we measured surgical blood loss using a tablet computer programmed with a unique algorithm modeled after facial recognition technology. The aim of the study was to assess the accuracy and performance of the system on surgical laparotomy sponges in vitro. METHODS:Whole blood samples of premeasured hemoglobin (Hb) and volume were reconstituted from units of human packed red blood cells and plasma and distributed across surgical laparotomy sponges. Normal saline was added to simulate the presence of varying levels of hemodilution and/or irrigation use. Soaked sponges from 4 different manufacturers were scanned using the Triton System with Feature Extraction Technology (Gauss Surgical, Inc., Palo Alto, CA) under 3 different ambient light conditions in an operating room. Accuracy of Hb loss measurement was evaluated relative to the premeasured values using linear regression and Bland-Altman analysis. Correlations between studied variables and measurement bias were analyzed using nonparametric tests. RESULTS:The overall mean percent error for measure of Hb loss for the Triton System was 12.3% (95% confidence interval [CI], 8.2%−16.4%). A strong positive linear correlation between the premeasured and actual Hb masses was noted across the full range of intraoperative lighting conditions, including (A) high (r = 0.95 [95% CI, 0.93–0.96]), (B) medium (r = 0.94 [95% CI, 0.93–0.96]), and (C) low (r = 0.90 [95% CI, 0.87–0.93]) mean ambient light intensity. Bland-Altman analysis revealed a bias of 0.01 g [95% CI, −0.03 to 0.06 g] of Hb per sponge between the 2 measures. The corresponding lower and upper limits of agreement were −1.16 g (95% CI, −1.21 to −1.12 g) per sponge and 1.19 g (95% CI, 1.15–1.24 g) per sponge, respectively. Measurement bias of estimated blood loss and Hb mass using the new system were not associated with the volume of saline used to reconstitute the samples (P = 0.506 and P = 0.469, respectively), suggesting that the system is robust under a wide range of sponge saturation conditions. CONCLUSIONS:Mobile blood loss monitoring using the Triton system is accurate in assessing Hb mass on surgical sponges across a range of ambient light conditions, sponge saturation, saline contamination, and initial blood Hb. Utilization of this tool could significantly improve the accuracy of blood loss estimates.

The effect of salvaged blood on coagulation function as measured by thromboelastography.

BACKGROUND: There is concern that salvaged blood has the potential to activate the coagulation system, which might place patients at risk of thrombotic complications. The aim of this study was to determine whether transfusion of salvaged blood after total knee arthroplasty (TKA) would lead to procoagulopathic changes as measured by thromboelastography (TEG) and furthermore if washing would reduce this risk.

Stored Platelet Functionality is Not Decreased After Warming with a Fluid Warmer

BACKGROUND:Warming of IV-administered fluids and blood products is routinely performed in the operating room to help maintain normothermia. Current guidelines recommend against the warming of platelets (PLTs), although there is no evidence for this prohibition in the literature. Our goal in this pilot study was to determine whether the warming of stored PLTs had any effect on their function. METHODS:Ten units of 3-day-old, PLT-rich plasma–derived whole blood PLTs were acquired from the transfusion service. A 5-mL aliquot was taken from each unit before warming (control samples). The remainder of the unit was then passed into a blood-warming device and held there for 2 minutes. Postwarming (warmed) PLT samples were then collected from the effluent end of the warming device. PLT aggregometry assays with adenosine diphosphate, collagen, and arachidonic acid as agonists were performed on the control and warmed samples. Thromboelastography tests were also performed on the control and warmed samples from 6 of the 10 PLT units. RESULTS:The mean temperature of the control and warmed samples was 22.4°C ± 0.5°C and 37.8°C ± 2.3°C, respectively. There was no significant difference (all P ≥ 0.13) in any of the PLT aggregometry assays or in the maximum amplitude of the thromboelastography test between the control and the warmed samples. The observed mean of only 1 parameter decreased (PLT aggregometry with 5 &mgr;M adenosine diphosphate) by 5% (95% confidence interval, −115% to 105%). The maximum change observed was PLT aggregometry with arachidonic acid as agonist, which increased by 116% (95% confidence interval, −91% to 323%). CONCLUSION:Although small in size, the results of this study do not support the prohibition against mechanical PLT warming. Studies of PLT activation after warming are also warranted.

Recommendations on Blood Recovery in Obstetrics

Hemorrhage is one of the leading preventable causes of maternal death. The safe use of blood recovery (also referred to as cell salvage) in obstetrics is well established. Blood recovery is the process by which blood is suctioned from the surgical field into a blood recovery device, where the blood is filtered, washed by centrifugation with a saline solution, and then transfused back to the patient. Blood recovery is recommended for elective cesarean sections where there is increased risk of hemorrhage (e.g., placenta previa/accreta, fibroid uterus, history of post-partum hemorrhage, etc.), or significant anemia at time of cesarean section regardless of risk factors for hemorrhage. Blood recovery is also recommended for emergency use in major obstetric hemorrhage from all causes. The safe and effective use of blood recovery requires a dedicated team of trained staff members.

Stationary versus agitated storage of whole blood during acute normovolemic hemodilution.

BACKGROUND:Acute normovolemic hemodilution is an intraoperative technique to reduce the number of red blood cells lost in shed blood during surgery. Standard guidelines for storage of platelets recommend constant gentle agitation to maintain gas exchange for the metabolically active platelets. The collected whole blood (WB) for acute normovolemic hemodilution remains stationary for as long as 8 hours before reinfusion. We hypothesized that gentle agitation of WB throughout storage would improve the coagulation properties of the WB at the time of reinfusion. METHODS:WB was collected from 10 volunteer donors and control samples taken. The units were split in 2 storage groups: agitated (rocked) and stationary (unrocked). Cell counts and fibrinogen levels, as well as thromboelastography (TEG®) measurements, including TEG® PlateletMapping® assays, were performed on the control sample and the test samples after 8 hours of rocked or unrocked storage at room temperature. RESULTS:Nine units WB from 9 different healthy volunteers were tested. There were no significant differences in hematocrit, hemoglobin, red blood cells counts, platelet counts, or fibrinogen levels between the control samples and the rocked and unrocked WB samples. WB coagulation as measured by TEG® was preserved during the 8-hour storage period in both the rocked and unrocked samples. There were no significant differences between the control, rocked, and unrocked samples in time to initiate clotting, time of clot formation, rate of clot formation, or maximum strength of clot values. There were also no significant differences in the fibrin contribution to clot strength between the control, rocked, and unrocked samples, and no significant difference between the platelet activation from adenosine diphosphate or arachidonic acid among any of the 3 groups. CONCLUSIONS:Given the small sample size, there is no statistical evidence on which to reject the null hypothesis of there being no difference in the changes from the baseline between coagulation function as measured by TEG® between WB that is either agitated or kept stationary for 8 hours. These findings need to be confirmed in a larger study.