Martin J. Macphee

Dry Fibrin Sealant Dressings Reduce Blood Loss, Resuscitation Volume, and Improve Survival in Hypothermic Coagulopathic Swine with Grade V Liver Injuries

OBJECTIVE The majority of early trauma deaths are caused by uncontrolled hemorrhage, and are frequently complicated by hypothermic and dilutional coagulopathies. Any hemorrhage-control technique that achieves rapid hemostasis despite a coagulopathy should improve the outcome of these patients. We conducted this study to determine whether dry fibrin sealant dressings (DFSD) would stop bleeding from grade V liver injuries in swine that were hypothermic and coagulopathic. METHODS Nineteen swine weighing 39.7 kg (mean and 95% confidence interval, 36.3-43.1), underwent a 60% isovolemic, hypothermic exchange transfusion with 33 degrees C 6% hetastarch to produce a dilutional and hypothermic coagulopathy. The animals then received a grade V liver injury and one of three treatments: DFSD, conventional liver packing with gauze sponges, or immunoglobulin G (IgG) placebo sealant dressing (blinded control). All animals were resuscitated with lactated Ringers solution to their preinjury mean arterial pressure. Blood loss after treatment, mean arterial pressure, resuscitation volume, hematologic variables, and core temperature were monitored for 1 hour. RESULTS At the time of injury, core temperature = 33.3 degrees C (95% confidence interval, 33.2-33.4), hemoglobin concentration = 4.4 g/dL (4.2-4.6), platelet count = 132 x 10(5)/microL, (93-171), prothrombin time = 21.6 seconds (19.6-23.5), activated partial thromboplastin time = 25.2 seconds (range, 22.9-27.5 seconds), and fibrinogen = 83 mg/dL (range, 76-89 mg/dL) across treatments. The posttreatment blood loss in the DFSD group was 669 mL, (range, 353-1,268 mL), which was lower (p < 0.01) than the means of 3,321 mL (range, 1,891-5,831 mL) and 4,399 mL (range, 2,321-8,332 mL) observed in the packing and IgG groups, respectively. The resuscitation volume in DFSD was 2,145 mL (range 1,310-3,514 mL), which was lower (p < 0.05) than the means of 5,222 mL (range 3,381-8,067 mL) and 5,542 mL (range 3,384-9,077 mL) in the packing and IgG groups, respectively. One-hour survival in the DFSD group was 83%, whereas survival in the packing and IgG groups were 0% (p < 0.05). CONCLUSION In swine with a grade V liver injury complicated by a dilutional and hypothermic coagulopathy, DFSD provided simple, rapid hemorrhage control, decreased fluid requirements, and improved survival.

Effect of dry fibrin sealant dressings versus gauze packing on blood loss in grade V liver injuries in resuscitated swine

BACKGROUND We conducted this study to determine whether the dry fibrin sealant dressing (DFSD) would stop bleeding from a grade V liver injury and to evaluate the effects of leaving the absorbable DFSD in survival animals. METHODS Twenty-four swine (40+/-3.0 kg) received a uniform grade V liver injury and were randomized to one of four 1-hour treatment groups: (1) gauze packing, (2) DFSD, (3) immunoglobulin G placebo dressing, and (4) no treatment. All animals were resuscitated with lactated Ringers solution. Total blood loss (TBL), mean arterial pressure, resuscitation volume, and laboratory data were monitored for 1 hour after injury. Four swine were treated with the DFSD after grade V injury and allowed to survive for 7 or 14 days. RESULTS The TBL was 1,104+/-264 mL (mean +/- SEM), 544+/-104 mL, 4,223+/-1,555 mL, and 6,026+/-1,020 mL for groups 1, 2, 3, and 4 respectively. TBL in DFSD animals was less than that in animals treated with gauze packing (p = 0.06). Grade V injuries were uniform among the 1-hour groups, and no evidence of intrahepatic abscess, unusual adhesions, or hepatic vein, vena caval, or pulmonary thromboses were noted in the long-term survival animals. CONCLUSION In this model of grade V liver injury, blood loss with the DFSD was 51% of that observed with standard gauze packing (not statistically different). Initial survival data revealed no complications attributable to the fibrin dressing. DFSD may provide simple, rapid, and definitive hemorrhage control in life-threatening liver injuries without the need for reoperation.

Hemostatic efficacy of a fibrin sealant–based topical agent in a femoral artery injury model: A randomized, blinded, placebo-controlled study

PURPOSE The efficacy of currently available topical hemostatic agents requires the formation of fibrin generated from circulating blood. Fibrin sealant, which is prepared from high concentrations of thrombin and fibrinogen, has been used in liquid form to promote hemostasis during vascular surgery. In a blinded, randomized, placebo-controlled fashion, we evaluated a dry dressing of purified, viral-inactivated human fibrinogen and human thrombin in a large animal model of arterial injury. METHODS Dressings were prepared by application of a layer of lyophilized human fibrin sealant or immunoglobulin G (IgG, control) to a silicone backing material. Six anesthetized female Yorkshire pigs (16 to 27 kg) received bilateral, 4 mm longitudinal femoral arteriotomies after surgical exposure of the arteries. The arteriotomies were not closed. In each animal a fibrin sealant dressing was applied to one artery and a control dressing to the other. Each dressing was secured on the arteriotomy by a mechanical device. After application of the dressings, blood flow was restored to each limb for 1 hour. The compressive device was released for 5 seconds at intervals of 15 minutes to assess hemostasis. Blood flow was measured distal to each arteriotomy with a dual-channel flowmeter to adjust equal bilateral compression. RESULTS Blood loss (mean +/- SEM) was significantly less from the arteriotomy treated with the fibrin-based dressing compared with the control dressing (4.9 +/- 4.0 ml versus 82.3 +/- 11.1 ml; p = 0.0005). Complete hemostasis was achieved at the first 15-minute interval in five of six arteriotomies treated with fibrin sealant and in none of the six control arteriotomies during 1 hour of assessment (p = 0.03). Blood flow through each femoral artery at baseline was the same in both treatment and control arteries (fibrin sealant, 114.2 +/- 17.4 ml/min; control, 106.7 +/- 16.5 ml/min; p = 0.24) and was not significantly different throughout the experiment. CONCLUSIONS Fibrin-based dressings provide effective hemostasis in a large animal model of arterial injury. Further development of these dressings will address optimal formulation and configuration for clinical use. Our results suggest that fibrin-based dressings will be effective in promotion of hemostasis in arterial bleeding, without compromising blood flow.

Fibrin sealant foam sprayed directly on liver injuries decreases blood loss in resuscitated rats

OBJECTIVE The majority of early trauma deaths are attributable to uncontrolled hemorrhage from truncal sites. A hemorrhage-control technique that reduced bleeding in the prehospital phase of treatment without requiring manual compression may improve the outcome of these patients. We conducted this preliminary study to determine whether an expanding fibrin sealant foam (FSF) would reduce bleeding from a severe liver injury even during resuscitation. METHODS Rats (n = 31; 291 +/- 5 g; 37.4 +/- 0.3 degrees C; mean +/- SEM), underwent a 60 +/- 5% excision of the median hepatic lobe. The animals received one of three treatments: (1) FSF, (2) immunoglobulin G placebo foam (IgGF), or (3) no treatment. All animals were resuscitated with 40 degrees C lactated Ringers solution at 3.3 mL/ min/kg to a mean arterial pressure of 100 mm Hg. Total blood loss, mean arterial pressure, and resuscitation volume were recorded for 30 minutes. A qualitative measure of foam coverage and adherence to the cut liver edge was recorded. RESULTS The total blood loss was less (p < 0.01) in the FSF group (21.2 +/- 5.0 mL/kg) than in either IgGF (41.4 +/- 4.3 mL/kg) or the no treatment group (44.6 +/- 4.7 mL/kg), which did not differ. The resuscitation volume was not different. The amount of foam used in the treated groups, 9.1 +/- 1.0 g in the FSF group and 10.0 +/- 1.0 g in the IgGF group, did not differ. Survival for 30 minutes was not different among groups. There was no difference in the amount of cut liver covered by either foam, but the clots were more adherent (p < 0.05) in the FSF group than in the IgGF group. CONCLUSION In rats with a severe liver injury, spraying fibrin foam directly on the cut liver surface decreased blood loss when compared with placebo foam and no treatment. This pilot study suggests a future possible treatment for noncompressible truncal hemorrhage.

IMPLICATIONS OF NEW DRY FIBRIN SEALANT TECHNOLOGY FOR TRAUMA SURGERY

Trauma patients have been bleeding to death for thousands of years. The methods used to control hemorrhage (tourniquets, pressure, bandages, and ligatures) have not changed for 2000 years. Technology now exists to amplify the normal clotting system with human proteins, thus providing almost instant hemorrhage control in the face of bleeding. The increasing body of clinical and animal research and safety data regarding new fibrin sealant technologies is compelling. When combined with the evolving concepts of extended trauma resuscitation, acceptance of this technology will finally add a new method of rapid, easy hemostasis to the armamentarium of the surgeon faced with an unstable hemorrhaging patient. Several important issues remain unresolved, such as optimal thrombin and fibrinogen content, amount of material required for hemostasis, long-term effects, distribution of breakdown products, and role of recombinant proteins. These issues are under active investigation. Despite these unanswered questions, the field of absorbable, off-the-shelf, rapidly active hemostatic agents that do not require refrigeration is an exciting area that should yield significant improvements in the care of injured patients.

Multicenter trial to evaluate the safety and potential efficacy of pooled human fibrin sealant for the treatment of burn wounds

OBJECTIVE The primary purpose of this multicenter study was to evaluate the safety and potential efficacy of a solvent/detergent-treated commercial fibrin sealant (human) for topical hemostasis in skin grafting. METHODS The study involved a prospective evaluation of changes in viral titers in patients with burns less than 15% after treatment with fibrin sealant (human). Each patient served as his/her own control for an unblinded, randomized comparison of donor site hemostasis and healing. Preoperative serum was obtained to screen for viral titers. At autografting, the recipient site and one of two randomly chosen donor sites were treated with fibrin sealant (human). The use of other hemostatic agents, including epinephrine was prohibited. Each donor site was covered with gauze to collect blood for estimation of the relative amount of bleeding. The healing of the graft and donor sites was observed. Viral titers and wounds were checked monthly for 6 months, and at 9 and 12 months postoperatively. RESULTS Viral titers for human immunodeficiency virus; hepatitis A, B, and C; Epstein-Barr virus; and cytomegalovirus were obtained before and after treatment. Of 47 patients, 34 completed the full year of observation. After treatment, there were no seroconversions to any of the aforementioned viruses. Bleeding at the recipient site appeared well controlled with fibrin sealant (human). Although investigators felt that fibrin sealant (human) improved donor site hemostasis, differences in hemoglobin measurements of blood-soaked dressings failed to reach significance. No differences were noted with regard to acceleration of donor site healing, graft take, or scar maturation at the two groups of donor sites. Anecdotally, the maturation of the recipient site appeared to be accelerated. CONCLUSION Fibrin sealant (human) is safe for use during excision and grafting, and its topical hemostatic potential needs to be examined in patients with larger burns. Its role in scar maturation also needs to be investigated.

Does the absorbable fibrin adhesive bandage facilitate partial nephrectomy

PURPOSE To evaluate the ability of the absorbable fibrin adhesive bandage (AFAB), a prototype product comprising lyophilized fibrinogen and thrombin on a VicrylTM mesh backing, to seal the collecting system and control bleeding after partial nephrectomy. MATERIALS AND METHODS Growing female pigs (n = 18) underwent left nephrectomy and a 40% (by length) right lower pole partial nephrectomy. One of three treatments was immediately applied: Conventional-closure of the collecting system, ligation of visible segmental vessels, application of SurgicelTM with bolstering sutures to the renal capsule; AFAB-application of up to two 4 x 4-inch AFABs held under pressure for 60 seconds; Placebo-application of a hemostatically inert VicrylTM bandage, visually identical to the AFAB. Blood loss and ischemic and total operative times were recorded, and abdominal computerized tomography (CT) was performed on postoperative day 6. Animals were sacrificed at 6 weeks to evaluate the remaining renal mass histologically. RESULTS Compared with conventional therapy, use of the AFAB resulted in significantly less bleeding (13 versus 68 ml., p <0.001) and lower operative (7.2 versus 16.3 minutes, p <0.001) and ischemic times (3.4 versus 7.8 minutes, p <0.001). Estimated blood loss in the placebo bandage group was dramatically higher (357 ml., p <0.001). Postoperative CT and histological sectioning suggested that the AFAB produces a stable, durable clot and that healing is at least as successful as with conventional treatment. CONCLUSION Use of the AFAB facilitated performance of partial nephrectomy by reducing blood loss and ischemic and total operative times. The AFAB appears equivalent to conventional surgery in its ability to seal the collecting system.

Delivery of demineralized bone powder by fibrin sealant

The main purpose of this study was to determine whether the use of fibrin sealant as a delivery vehicle for demineralized bone powder would result in bone induction in heterotopic and orthotopic sites. Rat demineralized bone powder alone or in different concentrations of fibrin sealant matrix (4, 8, 15, and 45 mg/ml) was bioassayed for bone induction by implantation in intramuscular sites. Distribution of treatment groups was as follows: demineralized bone powder alone (n = 12), demineralized bone powder plus 4 mg/ml fibrin sealant (n = 11), demineralized bone powder plus 8 mg/ml fibrin sealant (n = 11), demineralized bone powder plus 15 mg/ml fibrin sealant (n = 11), demineralized bone powder plus 45 mg/ml fibrin sealant (n = 10), 4 mg/ml fibrin sealant (n = 13), and 45 mg/ml fibrin sealant (n = 11). In a second group of rats, 8-mm critical-sized calvarial defects were created and treated with demineralized bone powder plus 30 mg/ml fibrin sealant. Intramuscular implants were retrieved after 28 days, while calvarial implants were retrieved at 28 days (n = 8), 3 months (n = 8), or 4 months (n = 5). Implants were then x-rayed and submitted for histology. Results showed bone formation as evidenced by radiopacity and histology. Radiopacity measurements of demineralized bone powder implants alone or in a fibrin sealant matrix were associated with immature woven bone at the implantation site. Fibrin sealant allowed bone formation by demineralized bone powder to occur, improved the handling of demineralized bone powder, and facilitated the shaping of implants.

Treatment of grade 4 renal stab wounds with absorbable fibrin adhesive bandage in a porcine model.

PURPOSE In a porcine model we evaluated the efficacy of the absorbable fibrin adhesive bandage and other novel fibrin products for treating major renal stab wounds. MATERIALS AND METHODS In commercial swine we produced an almost lethal, grade 4 renal stab wound via a 3.5 cm. sagittal, centrally located, through-and-through laceration. Each pig then received treatment in random fashion, including conventional oversewing of capsular defects with absorbable gelatin sponge and horizontal mattress sutures in 6, external absorbable fibrin adhesive bandage that was pressure held for 60 seconds in 6, external and internal absorbable fibrin adhesive bandage that was applied externally, inserted into the renal defect and pressure held for 60 seconds in 6, liquid fibrin sealant that was placed in the laceration and held for 60 seconds in 8, fibrin foam that was applied in the same manner as liquid fibrin in 5 and closing of the peritoneum over the lacerated kidney without further treatment in 6. Blood loss and time to hemostasis were recorded. Animals were sacrificed at 6 weeks to evaluate the injured renal unit. RESULTS Compared with conventional therapy the absorbable fibrin adhesive bandage applied externally alone or externally and internally resulted in significantly less bleeding and significantly less time to hemostasis (p <0.001). Liquid fibrin and fibrin foam did not reliably achieve hemostasis. Postoperatively computerized tomography and histological sectioning suggested that the absorbable fibrin adhesive bandage results in a stable, durable clot and healing is at least as successful as with conventional treatment. CONCLUSIONS The absorbable fibrin adhesive bandage appears to be a safe, rapid means of renal salvage after injury.

Intraoperative use of the absorbable fibrin adhesive bandage: long term effects.

PURPOSE The absorbable fibrin adhesive bandage (AFAB) reduces acute blood loss in experimental trauma models, but the effects on wound healing and subsequent function have heretofore not been investigated. Retropubic prostatectomy was selected to evaluate short and long term effects of using the AFAB intraoperatively. MATERIALS AND METHODS Dogs undergoing prostatectomy were randomly assigned to one of four treatments: CONTROL- sponges and manual pressure were applied after transecting the prostatic pedicles. Sponges were removed when the prostate was delivered. Vessels were isolated and ligated if bleeding continued after removal. AFAB- hemostatically active bandages were applied to the prostatic bed prior to sponges and pressure. Additional bandages were applied at the urethrovesical junction after completing the anastomosis. PLACEBO- visually identical (hemostatically inert) bandages were applied in an identical fashion. LIQUID SEALANT- concentrated thrombin and fibrinogen solution was applied to the vessels prior to sponges and pressure. Additional sealant solution was applied around the anastomosis. RESULTS Blood loss and time to achieve hemostasis were significantly less in the AFAB group compared with the other treatments. There were no differences in days to anastomotic integrity, continence, or intra-abdominal adhesions at necropsy six weeks later. CONCLUSIONS The AFAB can reduce surgery time and blood loss, with no decrement in wound healing or subsequent function.