Oral surgery in patients undergoing oral anticoagulant therapy.
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There is an evident need for procedural protocol for oral surgery patients who undergo oral anticoagulant treatment (OAT) because of: 1) the possible severity of complications and 2) the growing demand for OAT, which in some cases may be as much as 8% of the oral surgery patients that are referred to the hospital from primary care centers. In this study, the authors define the parameters for creating a proto- col applicable to this group of patients. The conclusion is that it is not necessary to suspend OAT before surgery; rather, these procedures should be performed under multidisciplinary medical control. OBJECTIVE: The authors demonstrate that it is possible to perform oral surgery on OAT patients, without having to sus- pend treatment beforehand. STUDY DESIGN: A longitudinal study was performed in OAT patients that required some type of oral surgical procedures. After an INR control, the patient underwent surgery and afterwards the patient was given tranexamic acid as a mouth rinse. Postoperative hemorrhage was classified as slight when it lasted less than 5 minutes, moderate when it lasted longer than five minutes, and severe when it required blood transfusion. RESULTS: The study was performed over a 5-year period (1996-2000), by the maxillofacial surgery department. In that time period, 125 patients with OAT were treated; 90 of them were males and 35 were females. Tooth extraction was per- formed in 229 sessions and a total of 367 teeth were extracted, with an average of 1.6% per session. With regards to postoperative hemorrahage, it was slight in 210 cases (91.7%), moderate in 18 (7.9%) and severe only in one case (0.4%). All the variables were compared and no statistically significant differences were found. CONCLUSIONS: We believe that OAT should not be suspended before oral surgery, but it surgery should be performed under multidisciplinary control-especially in the case of the elderly (over 65) or with those patients that have other concomitant illnesses such as renal insufficiency or anemia or other medical treatments. (+info)
Point-of-care testing for prothrombin time, but not activated partial thromboplastin time, correlates with laboratory methods in patients receiving aprotinin or epsilon-aminocaproic acid while undergoing cardiac surgery.
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Point-of-care testing (POCT) of coagulation parameters can help optimize transfusion practice in cardiac surgery. Antifibrinolytic agents may interfere with the laboratory and/or POCT coagulation assays. This randomized controlled study compared coagulation parameters obtained from a whole blood POCT coagulation device with a typical laboratory instrument in cardiac surgery patients receiving aprotinin, epsilon-aminocaproic acid, or normal saline before undergoing cardiopulmonary bypass. Aliquots of arterial blood samples from 42 patients were collected perioperatively, and their prothrombin times (PTs) and activated partial thromboplastin times (aPTTs) were measured by POCT and laboratory instrumentation. Linear regression and error analyses were used for the method comparison. For PT, the POCT device compared favorably with the laboratory method. For aPTT, the POCT device did not compare well with the laboratory method. Treatment with antifibrinolytic agents does not interfere with determination of PT. (+info)
Hemostatic alterations associated with supraceliac aortic cross-clamping.
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PURPOSE: The causative role of consumptive coagulopathy in the development of bleeding complications after supraceliac (SC) aortic cross-clamping (AXC) has been challenged by recent reports that ascribe this coagulopathy to primary fibrinolysis. This theory is made on the basis of evidence that tissue plasminogen activator (t-PA) antigen (Ag) levels increase after SC AXC. However, t-PA Ag levels reflect both active and inactive (bound to serum t-PA inhibitors) forms of serum t-PA, and elevations confirm the presence of fibrinolysis only in conjunction with an increase in t-PA activity. METHODS: To investigate the etiology of this coagulopathy, we submitted eight pigs to SC AXC and six pigs to infrarenal (IR) AXC for 30 minutes. Blood was drawn from the portal vein, the hepatic vein, and the carotid artery before AXC, just before unclamping, and 5, 30, and 60 minutes after unclamping. Prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen (FBG), platelets (PLT), thrombin-antithrombin complexes (TAT), t-PA Ag, t-PA activity, plasminogen activator inhibitor-1 (PAI-1), and alpha2-antiplasmin (AP) activities were measured. Statistical analysis was performed by using repeated measures analysis of variance and t tests RESULTS: The PT did not differ between the two groups at any point. After unclamping, in the SC group there was a drop in PLT levels (P =.005), a decrease in FBG levels (P <.001), and a trend toward PTT prolongation (P =.06) compared with baseline. In contrast, there were no changes in PTT, PLT levels, or FBG levels in the IR group. TAT, a serum marker of thrombin generation, increased with SC AXC (P =.04), remained elevated 5 minutes after unclamping (P =.08), and returned to normal 30 minutes after unclamping. In contrast, TAT levels did not change in the IR control group. In the SC AXC group, the TAT levels did not differ between the three test sites at any time. SC AXC was associated with an increase in t-PA Ag just before unclamping (P <.001) and 5 minutes after unclamping (P =.002), but IR AXC was not. t-PA activity levels decreased in both experimental groups 30 and 60 minutes after unclamping. Levels of alpha2-AP activity decreased to a similar degree in both groups after unclamping when compared with baseline CONCLUSION: Thirty minutes of SC AXC results in intravascular thrombosis that cannot be localized to the ischemic visceral circulation. This intravascular thrombosis is associated with consumption of clotting factors. Thirty minutes of SC AXC causes an activation of fibrinolytic pathways that does not result in a hyperfibrinolytic state. An increase in t-PA Ag without a rise in t-PA activity does not represent true fibrinolysis, but rather an increase in the bound, inactive forms of serum t-PA. Both IR and SC AXC result in decreased fibrinolytic activity ("fibrinolytic shutdown") after release of the aortic clamp. (+info)
Cerebral effects and blood sparing efficiency of sodium nitroprusside-induced hypotension alone and in combination with acute normovolaemic haemodilution.
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The combined reduction of oxygen-carrying capacity and perfusion pressure during the combination of acute normovolaemic haemodilution (ANH) and controlled hypotension (CH) raises concerns of hypoperfusion and ischaemic injury to the brain. Forty-two patients undergoing radical prostatectomy were prospectively allocated to receive CH induced by sodium nitroprusside (mean arterial pressure (MAP) 50 mm Hg), a combination of CH+ANH (post-ANH haematocrit 29%; intraoperative MAP 50 mm Hg), or standard anaesthesia (control). Serum levels of the brain-originated proteins neuron-specific enolase (NSE) and protein S-100, blood loss, transfusion requirements, adverse effects, and postoperative recovery profile were compared among the three groups. Intraoperative blood loss in the CH group (mean (SD)) (788 (193) ml) and CH+ANH group (861 (184) ml) was significantly less than in the control group (1335 (460) ml). Significantly fewer total units of allogeneic packed red blood cells (PRBC) were transfused in the patients receiving hypotensive anaesthesia (CH, 3 units; CH+ANH, 2 units; control, 17 units). There was no difference in immediate postoperative recovery profile among the three groups as determined by the emergence from anaesthesia and time to discharge from the postanaesthesia care unit. Serum S-100 protein concentrations increased significantly in all groups from baseline to peak concentrations 2 h postoperatively (CH 0.25 (0.11) microg litre(-1); CH+ANH 0.31 (0.12) microg litre(-1); control 0.31 (0.10) microg litre(-1)). A return to baseline values was seen within 24 h postoperatively in all patients. No changes in NSE concentrations were seen. Our observations suggest that CH and CH+ANH were effective in reducing blood loss and transfusion requirements in patients undergoing radical prostatectomy. Increased serum S-100 protein concentrations imply a disturbance in astroglial cell membrane integrity and an increased endothelial permeability of the blood-brain barrier. There were no associations between serum S-100 protein or NSE and adverse cognitive effects. Further work needs to be done to determine the prognostic importance of S-100 protein and NSE as surrogate variables of postoperative cerebral complications. (+info)
Original memoirs: the control of bleeding in operations for brain tumors: with the description of silver "clips" for the occlusion of vessels inaccessible to the ligature. 1911.
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One of the chief objects of concern in intracranial surgery should be the avoidance of any unnecessary loss of blood, for at best, in many cases of brain tumor associated with venous stasis, bleeding is likely to be so excessive as to necessitate postponement of the final steps of the procedure until a second or even a third session. The common methods of blood stilling by sponge, clamp, and ligature are largely inapplicable to intracranial surgery, particularly in the presence of bleeding from the nervous tissues themselves, and any device which serves as an aid to hemostasis in these difficult operations will bring a number of them to a safe termination at a single sitting, with less loss of blood and less damage to the brain itself. In addition to the more familiar tourniquet for the scalp, and wax for diploetic and emissary bleeding, suggestions are offered as to the use of gauze pledgets, dry sterile cotton, fragments of raw muscle and other tissues, as well as sections of organizing blood-clots for superficial meningeal bleeding, and silver "clips" for inaccessible individual points ether in dura or brain. The successful consummation of any critical operation often depends upon seeming trifles. It is, however, the scrupulous observance of surgical minutiae that makes possible the safe conduct of major intracranial performances--performances which a few years ago were attended in most cases by a veritable dance Macaber. (+info)
Methylene blue soldered microvascular anastomoses in vivo.
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OBJECTIVES: solders containing chromophores and proteins enhance the strength of lasered anastomoses. Methylene blue (MB) solder anastomoses in vitro are strong but no in vivo work has been reported. We used an MB solder in vivo and studied the effects of two laser powers on patency and histological appearance. DESIGN, MATERIALS AND METHODS: two groups of 15 rabbits had unilateral end-to-end carotid anastomoses (1.5-2.0 mm) formed using three stay sutures and MB solder. Group 1 anastomoses were formed at 5.7 Wcm(-1) and Group 2 at 2.8 Wcm(-1). The vessels were examined at various points by necropsy for patency and gross macroscopic appearance, with subsequent histological examination. RESULTS: group 2 showed patency of 93.3% v 0% ( p<0.001) endothelialisation of 100% v 26.6% ( p<0.001), giant cell formation 0% v 40.0% ( p<0.01), but stenosis was not significantly different (0% v 13.3% p=0.06). Group 2 showed a higher rate of intimal hyperplasia (IH) (66.6% v 20.0% p<0.05) but neither group exhibited thermal injury or aneurysm formation. CONCLUSIONS: laser soldered microvascular anastomoses were formed in vessels of 1.5-2.0 mm with a high degree of patency. A relationship appears to exist between laser power and anastomotic patency. Methylene blue fading has the potential to act as a switch against over exposure and a visual indicator of solder activation. (+info)
Intraspinal oxidised cellulose (Surgicel) causing delayed paraplegia after thoracotomy--a report of three cases.
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Oxidised regenerated cellulose (Surgicel) is a commonly used haemostatic agent in neurosurgery, thoracic surgery, and orthopaedics. We present three cases of paraplegia after thoracic surgery during which oxidised cellulose had been used during thoracotomy for haemorrhage control, and was later found to have passed through the intervertebral foramen causing spinal cord compression. In all intraspinal and perispinal procedures, the over-liberal use of Surgicel should be avoided, and attempts made to remove all excess Surgicel once adequate haemostasis is obtained. (+info)
Comparison of the topical haemostatic agents for the prevention of suture hole bleeding. An experimental study.
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OBJECTIVE: using a rabbit vascular graft model we investigated the use of fibrin glue (FG), gelatin-resorcinol-formaldehyde (GRF), and collagen (C) as a means of reducing suture hole bleeding. MATERIALS AND METHODS: twenty-eight rabbits were divided into four groups: fibrin glue, gelatin-resorcinol-formaldehyde, collagen and control. A 1 cm incision was made in the abdominal aortic wall of each animal. Incisions were covered with a polytetrafluoroethylene patch sutured with a 7-0 polypropylene. Fibrin Glue, GRF, and C were applied to cover suture holes in the groups 1, 2 and 3, respectively, but nothing in controls (group 4). The fibrin clot was allowed to achieve strength for 3 minutes before the clamps were reopened. After reopening the clamps, blood was collected from the surgical site using a syringe for a total of 2 min. RESULTS: mean blood loss was significantly lower in the FG, GRF, and C compared with control group (p=0.0022, p=0.0022, and p=0.0017, respectively). The volume of blood lost and the time of haemostasis in the group 1 (FG) was less than those in groups 2 and 3 (GRF and C, respectively) (p=0.001). The haemostasis (defined 2 min later) was achieved only in group 1 (FG) (p=0.00067). CONCLUSIONS: FG, GRF and C all reduce blood loss. Fibrin glue containing factor XIII was the most effective. (+info)