Use of high-intensity focused ultrasound to control bleeding.
OBJECTIVE: High-intensity focused ultrasound (HIFU) has been shown to be effective in controlling hemorrhage from punctures in blood vessels. The objective of the current study was to investigate the capability of HIFU to stop bleeding after a more severe type of vascular injury, namely longitudinal incisions of arteries and veins. METHODS: The superficial femoral arteries, common femoral arteries, carotid arteries, and jugular veins of four anesthetized pigs were exposed surgically. A longitudinal incision, 2 to 8 mm in length, was produced in the vessel. HIFU treatment was applied within 5 seconds of the onset of the bleeding. The HIFU probe consisted of a high-power, 3.5-MHz, piezoelectric transducer with an ellipsoidal focal spot that was 1 mm in cross section and 9 mm in axial dimension. The entire incision area was scanned with the HIFU beam at a rate of 15 to 25 times/second and a linear displacement of 5 to 10 mm. A total of 76 incisions and HIFU treatments were performed. RESULTS: Control of bleeding (major hemosatsis) was achieved in all 76 treatments, with complete hemostasis achieved in 69 treatments (91%). The average treatment times of major and complete hemostasis were 17 and 25 seconds, respectively. After the treatment, 74% of the vessels in which complete hemostasis was achieved were patent with distal blood flow and 26% were occluded. The HIFU-treated vessels showed a consistent coagulation of the adventitia surrounding the vessels, with a remarkably localized injury to the vessel wall. Extensive fibrin deposition at the treatment site was observed. CONCLUSION: HIFU may provide a useful method of achieving hemostasis for arteries and veins in a variety of clinical applications. (+info)
Pseudoaneurysm of the vertebral artery.
Pseudoaneurysms of the vertebral artery are rare. Their treatment depends on the location, size, cause, and coexisting injuries. The surgical management of a 22-year-old man who had a large pseudoaneurysm in the 1st portion of the right vertebral artery is described, and an additional 144 cases from the medical literature are briefly reviewed. (+info)
Acute normovolaemic haemodilution vs controlled hypotension for reducing the use of allogeneic blood in patients undergoing radical prostatectomy.
Blood loss in patients undergoing radical prostatectomy may be substantial. In a randomized, prospective study, we assessed two methods of reducing the need for allogeneic blood transfusion with regard to efficacy and costs. Sixty patients undergoing retropubic radical prostatectomy were allocated randomly to one of three groups. In group 1 (n = 20), acute normovolaemic haemodilution (ANH) was initiated after induction of anaesthesia; autologous blood 15 ml kg-1 was withdrawn and replaced by colloid solutions (gelatin) to maintain haemodynamic stability. In group 2 (n = 20), controlled hypotension was established using sodium nitroprusside (target mean arterial pressure (MAP) approximately 50 mm Hg). Group 3 (n = 20), without manipulations, served as a control group. Troponin T (TnT), a sensitive marker for myocardial ischaemia, and various coagulation variables were measured in the perioperative period. Packed red blood cells (PRBC) were given when haemoglobin concentration was less than 7 g dl-1. Cost calculations did not include hospital overhead costs or staff costs. In the ANH group, mean 1278 (SD 150) ml of autologous blood were withdrawn. Significantly more volume was infused in the ANH patients (gelatin 2450 (550) ml) than in the two other groups. Coagulation data (platelet count, activated partial thromboplastin time (aPTT), fibrinogen, antithrombin III (AT III), D-dimers) did not differ significantly between the three groups. The hypotension group had significantly lower blood loss (1260 (570) ml), whereas the ANH (1820 (680) ml) and control group (1920 (590) ml) did not differ significantly. Patients in the hypotension group needed significantly less PRBC (total 14 units; 75% of patients did not need PRBC) than the ANH (total 21 units; 55% of patients did not need PRBC) or control patients (total 28 units; 40% of patients did not need PRBC). Total costs were lowest in the hypotension group (41% less than in the control patients) (P < 0.05). We conclude that the use of hypotension during radical prostatectomy resulted in approximately 40% reduction in total transfusion costs. ANH was less effective and more costly than controlled hypotension. (+info)
Neurointerventional experience with an arteriotomy suture device.
We describe our experience with an arteriotomy closure device that has become a routine tool for the management of most patients in our neurointerventional service. In our experience, this device contributes significantly to patient comfort by allowing mobilization within 2 hours of a procedure, even with anticoagulants. Efficacy and safety of this suture device requires proctoring during initial experience. (+info)
Use of tranexamic acid for an effective blood conservation strategy after total knee arthroplasty.
We have investigated the effect of treatment with tranexamic acid, an inhibitor of fibrinolysis, on blood loss, blood transfusion requirements and blood coagulation in a randomized, double-blind, placebo-controlled study of 42 patients after total knee arthroplasty. Tranexamic acid 15 mg kg-1 (n = 21) or an equivalent volume of normal saline (n = 21) was given 30 min before surgery and subsequently every 8 h for 3 days. Coagulation and fibrinolysis values, blood loss and blood units administered were measured before administration of tranexamic acid, 8 h after the end of surgery and at 24 and 72 h after operation. Coagulation profile was examined (bleeding time, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), plasminogen, beta-thromboglobulin and fibrinogen). Fibrinolysis was evaluated by measurement of concentrations of D-dimer and fibrinogen degradation products (FDP). Total blood loss in the tranexamic acid group was 678 (SD 352) ml compared with 1419 (607) ml in the control group (P < 0.001), and occurred primarily during the first 24 h after surgery. Thirteen patients received 1-5 u. of packed red blood cells in the control group compared with two patients in the tranexamic acid group, who received 3 u. (P < 0.001). Postoperative packed cell volume values were higher in the tranexamic acid group despite fewer blood transfusions. Postoperative concentrations of plasminogen were decreased significantly in the tranexamic acid group (P < 0.001). Platelet count, PT, aPTT, bleeding time, beta-thromboglobulin, fibrinogen and FDP concentrations did not differ between groups, but D-dimer concentrations were increased in the control group. Thromboembolic complications occurred in two patients in the control group compared with none in the tranexamic acid group. (+info)
Tourniquet use during varicose vein surgery: a survey of current practice among Wessex surgeons.
The use of a tourniquet during varicose vein surgery, has been shown, through previous randomised trials, to result in a significant reduction in blood loss, superior post-operative cosmesis with no increase in operating time. Nonetheless, it would seem that few surgeons use this technique. Using postal questionnaires (n = 107), we have assessed the views and current practice among general surgeons (consultants and higher surgical trainees) in Wessex where the method was first proposed, to see how widely it has been adopted. We find that the majority (69.5%) of general surgeons in Wessex never use a tourniquet during varicose vein surgery. Possible reasons for this include the belief that it is time consuming, inconvenient, compromises the sterility of the operative field and confers no advantage. We conclude, however, that by not using a tourniquet during varicose vein surgery, surgeons are overlooking an important, evidence-based technique. Given that in the UK over 50,000 patients per year undergo operative varicose vein procedures, this can only adversely affect the delivery of quality healthcare to a large group of patients. (+info)
Varicose veins made easy!
A novel device that is more convenient than other tourniquet systems is described. (+info)
Platelet function during cardiopulmonary bypass not changed by two different doses of aprotinin.
BACKGROUND AND OBJECTIVE: Bleeding is one of the major complications of cardiopulmonary bypass (CBP) during cardiac surgery. A platelet function defect seems to be the main cause of the hemostatic problems associated with CBP. Controversial results have been reported concerning the possible protective mechanism of action of aprotinin on platelets. DESIGN AND METHODS: In this study we investigated the effect of two different dosages of aprotinin (high and pump-prime-only dose) on platelet reactivity in vitro and adhesion, activation and aggregation receptors on the platelet surface. RESULTS: The results obtained from 53 patients undergoing CBP showed a significantly deficient platelet aggregation in response to agonist in all groups without differences between aprotinin treated or not treated patients. No changes in platelet surface expression of glycoprotein (GP) IIb-IIIa, GPIb, GPIV and P-selectin, were observed during CBP between patients treated with aprotinin or not. INTERPRETATION AND CONCLUSIONS: These data suggest that inadequate platelet function induced by CBP is not a defect intrinsic to the platelet. We conclude that the hemostatic effect of aprotinin, regardless of the dose employed, is not mediated by protection of platelet function. (+info)