External Pneumatic Compression Research Articles

Pneumatic Compression Versus Low Molecular Weight Heparin in Gynecologic Oncology Surgery: A Randomized Trial

Venous thromboembolism is a dangerous postoperative complication that occurs in as many as 14% of patients after gynecologic surgery and 38% of women after surgery for gynecologic oncology. To study the value of low-molecular-weight heparin in preventing thromboembolism, the authors conducted a randomized trial comparing the efficacy and complication rates of low molecular-weight heparin and external pneumatic compression in women scheduled to undergo gynecologic oncology surgery at Duke Medical Center. Patients randomly assigned to external pneumatic compression were placed in sleeves before surgery and wore them for the first 5 days and thereafter until they were ambulatory. Patients receiving low-molecular-weight heparin were given 2500 units subcutaneously 1 to 2 hours before surgery and again 12 hours after surgery. They received 5000 units daily for the first 5 postoperative days and each day thereafter until discharge. On the third to the fifth postoperative day, all patients were evaluated for the presence of occult deep vein thrombosis using bilateral Doppler ultrasound. In addition, each patient was interviewed by phone 1 month after surgery and asked about signs and symptoms suggestive of thrombosis. In the perioperative period, proximal lower extremity deep vein thrombosis was diagnosed in three women, one in the pneumatic compression group and two in the low molecular-weight heparin group. All were asymptomatic. The estimated blood loss at surgery, intraoperative and postoperative transfusions, and other complications were similar for both groups. The low molecular-weight heparin was discontinued in three patients who had excessive bleeding during surgery and in one patient whose platelet count dropped to less than 60. On the first postoperative day, low platelet counts (below 100,000) were seen in five women in the low molecular-weight heparin group and one in the external pneumatic compression group. On day three, low platelets were seen in six patients in the pneumatic compression group and two in the low molecular-weight heparin group. Linear regression analysis of laboratory values, including hematocrit, platelet count, and activated thromboplastin, found that the final postoperative hematocrit was significantly higher in the women with external pneumatic compression (P = .004). The maximum activated thromboplastin time was significantly higher in the women receiving low molecular-weight heparin (P = .01).

Pneumatic Compression Versus Low Molecular Weight Heparin in Gynecologic Oncology Surgery

In Brief OBJECTIVE To compare the efficacy and treatment-related complications of low molecular weight heparin and external pneumatic compression in the prevention of venous thromboembolism of postoperative gynecologic oncology patients. METHODS A total of 211 patients over age 40 years, undergoing a major operative procedure for gynecologic malignancy, were randomized to receive perioperative thromboembolism prophylaxis with either low molecular weight heparin (n = 105) or external pneumatic compression (n = 106). Demographic data and clinical outcome were recorded for each patient. All patients underwent bilateral Doppler ultrasound of the lower extremities on postoperative days 3–5 to evaluate for the presence of occult deep vein thrombosis. A follow-up interview 30 days after surgery sought to detect patients who developed deep vein thrombosis or pulmonary embolism after hospital discharge. RESULTS Venous thrombosis was diagnosed in two patients receiving low molecular weight heparin and in one patient receiving external pneumatic compression. The frequency of bleeding complications, measured by the number of required perioperative transfusions, and estimated intraoperative blood loss was similar between the two groups. CONCLUSION Low molecular weight heparin and external pneumatic compression are similarly effective in the postoperative prophylaxis of thromboembolism. The use of low molecular weight heparin is not associated with an increased risk of bleeding complications when compared with external pneumatic compression. We believe that both modalities are reasonable choices for prophylaxis in this high-risk group of patients. Low molecular weight heparin and external pneumatic compression are similarly effective in the postoperative prophylaxis of thromboembolism in gynecologic oncology patients.

Pneumatic compression versus low molecular weight heparin in gynecologic oncology surgery: a randomized trial

OBJECTIVE: To compare the efficacy and treatment-related complications of low molecular weight heparin and external pneumatic compression in the prevention of venous thromboembolism of postoperative gynecologic oncology patients. METHODS: A total of 211 patients over age 40 years, undergoing a major operative procedure for gynecologic malignancy, were randomized to receive perioperative thromboembolism prophylaxis with either low molecular weight heparin ( n = 105) or external pneumatic compression ( n = 106). Demographic data and clinical outcome were recorded for each patient. All patients underwent bilateral Doppler ultrasound of the lower extremities on postoperative days 3–5 to evaluate for the presence of occult deep vein thrombosis. A follow-up interview 30 days after surgery sought to detect patients who developed deep vein thrombosis or pulmonary embolism after hospital discharge. RESULTS: Venous thrombosis was diagnosed in two patients receiving low molecular weight heparin and in one patient receiving external pneumatic compression. The frequency of bleeding complications, measured by the number of required perioperative transfusions, and estimated intraoperative blood loss was similar between the two groups. CONCLUSION: Low molecular weight heparin and external pneumatic compression are similarly effective in the postoperative prophylaxis of thromboembolism. The use of low molecular weight heparin is not associated with an increased risk of bleeding complications when compared with external pneumatic compression. We believe that both modalities are reasonable choices for prophylaxis in this high-risk group of patients.

In reply.

In reply: Dr. Schreiber's letter draws attention to the lack of data regarding the optimal duration of antithrombotic therapy for prevention of venous thromboembolism (VTE) in the high-risk older surgical patient. Although the clinical practice guidelines1 refer to the use of warfarin, this issue applies to alternative therapies as well, including intermittent external pneumatic leg compression and low-dose unfractionated and low-molecular-weight heparins, although comparisons in efficacy between each are also not entirely clear. The risk for VTE increases with age.2, 3 Other risk factors include prolonged immobility or paralysis; prior VTE; cancer; major surgery (particularly operations involving the abdomen, pelvis, and lower extremities); obesity; varicose veins; congestive heart failure; myocardial infarction; stroke; fracture of the pelvis, hip, or leg; indwelling femoral vein catheter; inflammatory bowel disease; nephrotic syndrome; and estrogen use.4 The guideline recommends prophylactic antithrombotic therapy be continued for not less than 3 months or until the patient is ambulatory. Many older surgical patients regain ambulatory status during hospitalization or shortly thereafter. Those remaining bedfast pose the highest risk for VTE and continuation of antithrombotic therapy should be considered for them. As noted, several trials of antithrombotic therapy after hospitalization in patients undergoing hip replacement have found a significant incidence of asymptomatic DVT by venogram at 6 weeks in the placebo groups, with reduction in the incidence of VTE in the treated groups.5-8 One recent study of ardeparin prophylaxis for VTE in total hip and knee replacement patients, however, found that 6 weeks of postoperative therapy did not further reduce VTE incidence beyond that achieved with 4 to 10 days of therapy.9 Reduction in VTE risk must be weighed against the risk of bleeding with antithrombotic treatment. Bleeding risk is most closely associated with the intensity of therapy, which is usually lower for VTE prophylaxis. Additional risk factors include a history of gastrointestinal bleeding, cerebrovascular disease, and renal and hepatic disease.10 To provide some magnitude, the risk of intracranial hemorrhage is 0.3%/year and extracranial hemorrhage is 0.6%/year for warfarin prophylaxis of stroke in atrial fibrillation.11 In summary, it is difficult to extrapolate from currently available data what is the optimal duration of antithrombotic prophylaxis for VTE in non-ambulatory older patients following high-risk surgery; the potential benefit must be weighed against the risk for each patient.

Hemodynamics of the lower extremity with pneumatic foot compression. Effect on leg position

External pneumatic compression of the foot is being used more and more to increase the venous blood flow in the lower limbs and thus reduce the risk of postoperative deep venous thrombosis. We have investigated the efficacy of the foot pump pneumatic compression device (A-V Impulse, Novamedix, Andover, England) in 10 healthy subjects and in 10 patients undergoing total hip arthroplasty. The velocity of venous blood flow in the common femoral artery was measured in the horizontal, Trendelenburg (head-down, foot-up) and reverse Trendelenburg (head-up and foot-down) positions using a duplex ultrasound unit (Sonoline Elegra, Siemens, Erlangen, Germany) with a 5 MHz linear array probe. Application of the foot pump produced an increase in venous blood flow velocity in all healthy subjects and in all patients. In healthy subjects the mean increase in the horizontal position was 31.18% (SD = 15.86%), and in the Trendelenburg position 20.72 (SD = 15.69%) (right limb). In the reverse Trendelenburg position, the foot pump produced a mean increase of 94.08% (SD = 55.00%). The difference is statistically significant (p < 0.005). In patients with a total hip arthroplasty, the mean increase in the horizontal position was 28.67% (SD = 9.95%), and in the Trendelenburg position 20.34% (SD = 17.85%) (operated limb). In the reverse Trendelenburg, the foot pump produced a mean increase of 91.55% (SD = 42.38%). The difference is statistically significant (p < 0.005). There was no noteworthy difference in results between the controls and patients. Pneumatic compression devices designed to reduce venous stasis are effective in decreasing the rate of deep venous thrombosis after surgery on the lower limb. The results of the present study show that the efficiency of the foot pump in increasing venous return is improved by adopting the reverse Trendelenburg position. This may increase its thromboprophylactic effect.

An in vitro cell culture system to study the influence of external pneumatic compression on endothelial function

Purpose: External pneumatic compression (EPC) is an effective means of prophylaxis against deep venous thrombosis. However, its mechanism remains poorly understood. Understanding of the biological consequences of EPC is an important goal for optimizing performance of the EPC-generating device and providing guidance for clinical use. We present a new in vitro cell culture system (Venous Flow Simulator) that simulates blood flow and vessel collapse conditions during EPC, and we examine the influence of these factors on endothelial cell (EC) fibrinolytic activity and vasomotor function. Methods: An in vitro cell culture system was designed to replicate the hemodynamic shear stress and vessel wall strain associated with induced blood flow during different modes of EPC. Human umbilical vein endothelial cells were cultured in the system and subjected to intermittent flow, vessel collapse, or a combination of the two. The biologic response was assessed through changes in EC morphology and the expression of fibrinolytic factors tissue plasminogen activator, plasminogen activator inhibitor type 1, profibrinolytic receptor (annexin II), and vasomotor factors endothelial nitric oxide synthase and endothelin–1. Results: The cells remained attached and viable after being subjected to intermittent pulsatile flow (F) and tube compression (C). In F and F + C, cells aligned in the direction of flow after 6 hours. Northern blot analysis of messenger RNA shows that there is an upregulation of tissue plasminogen activator expression (1.95 ± 0.19 in F and 2.45 ± 0.46 in FC) and endothelial nitric oxide synthase expression (2.08 ± 0.25 in F and 2.11 ± 0.21 in FC). Plasminogen activator inhibitor type 1, annexin II, and endothelin 1 show no significant change under any experimental conditions. The results also show that pulsatile flow, more than vessel compression, influences EC morphology and function. Conclusion: Effects on ECs of intermittent flow and vessel collapse, either individually or simultaneously, were simulated with an in vitro system of new design. Initial results show that intermittent flow associated with EPC upregulates EC fibrinolytic potential and influences factors altering vasomotor tone. The system will facilitate future studies of EC function during EPC. (J Vasc Surg 2000;32:977-87.)

External pneumatic compression and fibrinolysis in abdominal surgery

Introduction: External pneumatic compression (EPC) devices prevent lower extremity deep venous thrombosis by increasing venous flow and thereby reducing stasis. Early studies suggested that they also enhance systemic fibrinolytic activity and thus prevent thrombus formation; more recent studies have been conflicting. The hypothesis of this study was that EPC devices enhance systemic fibrinolysis or reduce postoperative fibrinolytic impairment in patients undergoing abdominal surgical procedures. Methods: Each of 48 patients (98% male; mean age, 67 years) undergoing major intra-abdominal surgical procedures (36 bowel procedures, 12 aortic reconstructions) was prospectively randomized to one of three treatments for deep venous thrombosis prophylaxis: subcutaneous heparin injections (HEP group), use of a thigh-length sequential EPC device (EPC group), or both (HEP + EPC group). Antecubital venous samples were collected for measurement of systemic fibrinolytic activity on the day before surgery, after induction of anesthesia but before prophylaxis was initiated, and on postoperative days 1, 3, and 5. Fibrinolysis was assessed through measurement of the activities of the rate limiting fibrinolytic activator, tissue plasminogen activator, and its inhibitor plasminogen activator inhibitor-1 with amidolytic methods. Results: On the day before surgery, plasminogen activator inhibitor-1 activity was elevated in all groups in comparison with that in age-matched and sex-matched controls (20.3 ± 0.6 AU/mL). In the HEP group, plasminogen activator inhibitor-1 activity was further elevated above the value for the day before surgery on postoperative day 1 (28.5 ± 4.3 AU/mL; P =.04) and postoperative day 3 (25.1 ± 1.9 AU/mL; P =.07). No significant decrease in plasminogen activator inhibitor-1 activity occurred in either group treated with EPC devices in comparison with the HEP group at any time. There were no changes in tissue plasminogen activator activity postoperatively in the HEP group and no significant increases in either EPC group at any point. Conclusions: Reduced systemic fibrinolytic activity (“fibrinolytic shutdown”) occurred in these patients after abdominal surgery; it was manifested as increased plasminogen activator inhibitor-1 activity. EPC devices did not enhance systemic fibrinolysis or prevent postoperative shutdown either by decreasing plasminogen activator inhibitor-1 activity or by increasing tissue plasminogen activator activity. These data suggest that EPC devices do not prevent deep venous thrombosis by fibrinolytic enhancement; effective prophylaxis is achieved only when the devices are used in a manner that reduces lower extremity venous stasis. (J Vasc Surg 2000;32:537-43.)

Circulator boot therapy alters the natural history of ischemic limb ulceration.

Despite numerous advances in interventional radiology and vascular surgery, the clinician continues to be confronted with inoperable vascular disease. Previous studies have shown that ulceration associated with a transcutaneous oxygen pressure (tcPO2) of <20 mmHg is refractory to all attempts at healing. External pneumatic compression for the treatment of peripheral vascular disease has been available for several years, although there is a relative paucity of data regarding its role in clinical practice as well as its efficacy. The objective of this study was to examine the experience with circulator boot therapy in the treatment of ischemic ulcers in the absence of osteomyelitis, and specifically to determine whether such therapy can be of benefit in ischemic limb ulceration associated with a tcPO2 of <20 mmHg. A retrospective chart review was undertaken of ail patients with a lower limb ulcer who, in the absence of osteomyelitis, underwent circulator boot therapy at the Gonda Vascular Center. A total of 98 patients was identified. Two patients died within 1 month of commencing therapy and were not included in further analysis. The tcPO2 data were unavailable in five patients. Outcome in the patient population was classified as favorable if (1)healing was achieved, (2)the ulcer decreased in size, or (3) the affected limb improved sufficiently to allow successful revascularization. An unfavorable outcome was one where a major amputation was performed or where the ulcer increased in size. Out of a total of 29 patients with a tcPO2 <20 mmHg at the area of ulceration, 19 had a favorable outcome following circulator boot therapy. Of the remaining 62 patients with a tcPO2 >20 mmHg, 54 had a favorable outcome. Circulator boot therapy is associated with improved outcomes in limb ulceration due to peripheral vascular disease. Complete ulcer healing as well as preservation of the affected limb can be achieved in most cases.

Cost-effectiveness of deep venous thrombosis prophylaxis in gynecologic oncology surgery

Objective: To estimate the cost-effectiveness of preventive strategies for deep vein thrombosis (DVT) in patients undergoing surgery for gynecologic cancer. Methods: A model was constructed to estimate the costs and outcomes associated with the use of external pneumatic compression, unfractionated heparin, and low molecular weight heparin in women with cervical, endometrial, and ovarian cancer. We estimated cost per DVT prevented, per fatal pulmonary embolus (PE) prevented, and per life-year saved. Probability estimates for various outcomes and efficacies were obtained from the literature, using data specific for gynecologic patients when available. Results: Cost-effectiveness estimates ranged from $27 per life-year saved for a 55-year-old endometrial cancer patient to $5132 per life-year saved for a 65-year-old with ovarian cancer. Although low molecular weight heparin and unfractionated heparin were cost-effective compared with no prophylaxis, each was less effective than external pneumatic compression in the base case. The results of the analysis were sensitive to assumptions about the relative risk of DVT, the life expectancy of the patient, the costs of future treatment, and the relative effectiveness of the different strategies: If unfractionated heparin or low molecular weight heparin is at least 2–3% more effective than external pneumatic compression, then the incremental cost per life-year of either would be less than $50,000 compared with external pneumatic compression. Conclusion: Prophylaxis of DVT is cost-effective in terms of life-years gained even for patients with relatively short life expectancies, such as ovarian cancer patients. External pneumatic compression appears to be the most cost-effective strategy under our baseline assumptions, but further studies in gynecologic cancer are needed to validate our conclusions.

The effects of external compression on venous blood flow and tissue deformation in the lower leg.

External pneumatic compression of the lower legs is effective as prophylaxis against deep vein thrombosis. In a typical application, inflatable cuffs are wrapped around the patient's legs and periodically inflated to prevent stasis, accelerate venous blood flow, and enhance fibrinolysis. The purpose of this study was to examine the stress distribution within the tissues, and the corresponding venous blood flow and intravascular shear stress with different external compression modalities. A two-dimensional finite element analysis (FEA) was used to determine venous collapse as a function of internal (venous) pressure and the magnitude and spatial distribution of external (surface) pressure. Using the one-dimensional equations governing flow in a collapsible tube and the relations for venous collapse from the FEA, blood flow resulting from external compression was simulated. Tests were conducted to compare circumferentially symmetric (C) and asymmetric (A) compression and to examine distributions of pressure along the limb. Results show that A compression produces greater vessel collapse and generates larger blood flow velocities and shear stresses than C compression. The differences between axially uniform and graded-sequential compression are less marked than previously found, with uniform compression providing slightly greater peak flow velocities and shear stresses. The major advantage of graded-sequential compression is found at midcalf. Strains at the lumenal border are approximately 20 percent at an external pressure of 50 mmHg (6650 Pa) with all compression modalities.

A Comparison of Compression Pumps in the Treatment of Lymphedema

Purpose: This study was done in order to ascertain which methods of mechanical compression would be optimum in treating patients with primary and secondary lymphedema. Materials and Methods: Thirty-five patients (26 women, 9 men) were enrolled in the study. The women ranged in age from 36 to 82 years (mean 56.9 years). The men ranged in age from 31 to 83 years (mean 56.4 years). Ultimately, 32 patients completed the study. Each patient was treated by random assignment to each of the three types of compression pumps. The treatment arms were as follows: (1) unicompartmental nongradient pump with pressure of 50 mm Hg, (2) a three-compartment pump with segmental, nongradient pressures of 50 mm Hg in each of three cells, and (3) a multicompartmental gradient pressure pump with ten cells ranging in pressure from 80 at the most distal to 30 at the most proximal. There were 35 extremities treated by each of the three methods. Eleven had primary lymphedema and 24 had secondary lymphedema. Results: The mean percentage volume change was +0.4% in the limbs treated with the unicompartmental pump, +7.3% in the three-compartment pump, and -32.6% in the ten-compartment pump. By use of Kruskal and Wallis, one-way ANOVA on ranks, a significant difference between the three treatments was detected (p &lt; 0.001). In treatment of primary lymphedema there was no difference between the subgroups with regard to the effect of the three compression pumps. In treatment of secondary lymphedema, there was no reduction in the size of the limbs treated with the single-compartment, there was a -4.65% reduction in the three-compartment pump treatment, and -28.4% in the tencompartment pump. There were no differences in treatment of secondary limbs with and without radiation. In an analysis comparing primary to secondary lymphedema with and without radiation, the results were not statistically different from one another. Other factors such as severity of lymphedema, gender, duration of lymphedema, history of infection, and presence of radiation could not be implicated as having prognostic significance or having any effect on response to therapy. Conclusions: Mechanical external pneumatic compression can produce a reduction in treated limb volumes in primary and secondary lymphedema. This is best achieved by multicompartment sequential compression. Limb volume reduction by single or three compartment devices is decidedly less effective in treatment of lymphedema.

Interventions for varicosities and leg oedema in pregnancy.

Leg oedema from venous insufficiency is not dangerous but it can cause women symptoms such as pain, feelings of heaviness, night cramps and paraesthesiae. Leg oedema can be a sign of pre-eclampsia when associated with raised blood pressure or proteinuria. The objective of this review was to assess the effects of treatment to relieve the symptoms associated with varicosity in pregnancy and to reduce leg oedema. We searched the Cochrane Pregnancy and Childbirth Group trials register. Randomised trials of any form of treatment for varicosity or leg oedema in pregnancy. Trial quality was assessed and data were extracted independently by two reviewers. Three trials of three different treatments were included. A total of 115 women were involved. In one trial, two thirds of women given rutoside capsules in the last three months of pregnancy noted an improvement in symptoms compared with only one third given placebo (odds ratio 0.30, 95% confidence interval 0.12 to 0.77). They had a decrease in ankle circumference at 36 weeks' gestation after eight weeks of treatment, while women given placebo had a small increase. In one trial, women with ankle oedema had a small non-significant reduction in lower leg volume when treated with external pneumatic intermittent compression for 30 minutes. Fifty minutes immersion in water at 32 degrees Celsius resulted in greater diuresis and fall in blood pressure than 50 minutes bedrest. Rutosides appear to relieve symptoms of venous insufficiency in late pregnancy. However it is not known if the drug is safe in pregnancy. External pneumatic compression appears to reduce ankle swelling. Immersion in water for 50 minutes results in diuresis and fall in blood pressure. It is not known for how long these changes are sustained nor whether they are of any benefit.

Venous outflow of the leg: anatomy and physiologic mechanism of the plantar venous plexus.

Mechanisms of venous outflow from the leg and foot have not been clearly defined. The purpose of this study was to evaluate the anatomy and physiologic mechanism of the plantar venous plexus and its impact on venous drainage from the tibial veins. Fifty phlebograms that contained complete foot and calf films were reviewed. On lateral films, the number of veins in the plantar venous plexus and its tibial outflow tract were counted. The length and diameter of the longest vein in the plantar venous system and the length of the foot arch were measured. The ratio of the length of the plantar venous plexus to the arch length was calculated. The presence or absence of valves within the plexus was recorded. Plantar venous plexus outflow was evaluated by an duplex ultrasonographic scan of the posterior tibial, anterior tibial, and peroneal veins during intermittent external pneumatic compression of the plantar surface of the foot. The plantar venous plexus was composed of one to four large veins (mean, 2.7 veins) within the plantar aspect of the foot. The diameter of these veins was 4.0 +/- 1.2 mm. The veins coursed diagonally from a lateral position in the forefoot to a medial position at the level of the ankle, spanning 75% of the foot arch. Prominent valves were recognized within the plantar veins in 22 of 50 patients. The plexus coalesced into an outflow tract of one to four veins (mean, 2.5 veins) that flowed exclusively into the posterior tibial venous system. Small accessory veins that drained the plantar surface of the forefoot flowed into either the posterior tibial or peroneal veins. This pattern of selective drainage of the plantar venous plexus was confirmed by duplex imaging. Mechanical compression of the plantar venous plexus produced a mean peak velocity in the posterior tibial veins of 123 +/- 71 cm/sec, in the anterior tibial veins of 24 +/- 14 cm/sec, and in the peroneal veins of 29 +/- 26 cm/sec. The plantar venous plexus is composed of multiple large-diameter veins that span the arch of the foot. Compression of the plantar venous plexus, such as that which occurs during ambulation, is capable of significantly increasing flow through the posterior tibial venous system into the popliteal vein. Its function may be integral to venous outflow from the calf and priming of the more proximal calf muscle pump.

Perioperative morbidity of intracavitary gynecologic brachytherapy

Purpose : To define the incidence and severity of perioperative morbidity and its subsequent management with standard tandem and ovoid insertions and to evaluate pretreatment and treatment factors associated with an increased risk of perioperative morbidity. Methods and Materials : Ninety-five tandem and ovoid insertions were performed at the Fox Chase Cancer Center between 1985 and 1992 for cervical ( n = 91) and endometrial ( n = 4) cancer. Patients were placed on antibiotics in 19%, usually for a positive routine preoperative urine culture, but no patient was given prophylactic antibiotic therapy. Deep-vein thrombosis prophylaxis was practiced for 70% of implants and included subcutaneous heparin (40%), graduated compression elastic stockings (16%), and external pneumatic calf compression (14%). All patients were placed on prophylactic diphenoxylate hydrochloride, with doses ranging from three to eight tablets/day. Results : Intraoperative complications were seen in 3% of implants and included two perforations and a vaginal laceration in two patients. Twenty-four percent of implants (16 patients) developed temperatures of > 100.5 (range 100.6 to 103), although only one patient required implant removal because of fever. Management of fever included antibiotics in 35% and acetaminophen only in 65%. Five implants (5%) were removed emergently secondary to presumed sepsis ( n = 1), exacerbation of chronic obstructive pulmonary disease, hypotension, change in mental status ( n = 3), and myocardial infarction/congestive heart failure ( n = 1). No patient developed a deep-vein thrombosis, pulmonary embolism, gastrointestinal obstruction, or died of a postoperative complication. Univariate analysis of pretreatment and treatment factors revealed older age ( p < 0.005) and spinal/epidural anesthesia ( p < 0.02) to be associated with increased perioperative morbidity, and older age ( p < 0.05) and higher ASA classification ( p < 0.02) to be associated with severe complications requiring removal of implant. Multivariate analysis revealed only older age ( p < 0.01) to be significantly related to perioperative morbidity. Conclusions : Fever of > 100.5 was seen in 24% of implants and can be managed successfully without removal of the implant in 96% of cases. Use of antibiotics preoperatively and intraoperatively did not reduce the risk of perioperative temperature elevation. Use of routine diphenoxylate hydrochloride prophylaxis was tolerated without ileus or gastrointestinal obstruction clinically. Although routine deep-vein thrombosis prophylaxis is reasonable, our data would support a low risk of deep-vein thrombosis for untreated patients. Severe perioperative morbidity necessitated premature implant removal in only 5% of cases and was related to older age in multivariate analysis.

Meta-analysis Pitfalls: Deep Venous Thrombosis in Patients Undergoing Elective Hip Surgery-Reply

Doctor Potyk raises a concern that although inclusion criteria for studies included in the meta-analysis of deep venous thrombosis prophylaxis were appropriate, some studies using different doses or products of a prophylactic agent were grouped inappropriately. He references data that suggest these differences result in different prophylactic efficacy. Although we do not dispute that delaying warfarin until the fifth day postoperatively or using 1 mg of warfarin both preoperatively and postoperatively may be inadequate dose schedules, the two warfarin-only studies that we included in our meta-analysis did not use these dose schedules. We, therefore, did not combine studies in which dosing differences are related to differences in efficacy. For external pneumatic compression and low-molecularweight heparin, he states the concern is only theoretic. Meta-analysis is the systematic overview of individual studies to combine results and integrate the findings to draw conclusions about the effectiveness of therapeutic interventions.^1,2Meta-analysis uses explicit

Prophylaxis of venous thromboembolism in brain tumor patients.

Thromboembolism is a common problem in patients with brain tumors. Within this population are subpopulations of patients at varying but substantial risk for deep vein thrombosis and pulmonary embolism. Prophylactic strategies can be applied to these various risk groups that will dramatically reduce the incidence of thromboembolism, and these should be applied on a routine basis. The standard prophylactic methods for thromboembolic prophylaxis include mechanical devices (e.g., graduated leg stockings; external pneumatic calf compression) and pharmacological agents (e.g., low dose heparin). In addition, a basic knowledge of low molecular weight heparins and heparinoids is essential because these new agents have a potentially promising role in the prophylaxis of neurological disease in certain patients. The principles concerning the prophylaxis of venous thromboembolic disease in patients with brain tumors are addressed in this review.

The pathogenesis and prevention of thromboembolic complications in patients undergoing total hip replacement

A 1987 survey of U.S. orthopedic surgeons found that 84% used some form of DVT prophylaxis. Ten percent used prophylaxis only for their "high-risk patients," and 6% never used prophylaxis. Twenty percent of the surgeons had at least one THR patient die from a fatal PE in the last five years. Fifty percent of the surgeons using warfarin had subsequently discontinued its use because of bleeding complications and monitoring difficulties. Compared with a survey done 13 years previously, this recent study showed a dramatic rise in the number of surgeons using DVT prophylaxis. The majority, however, were using methods that are ineffective: 67% used aspirin and 17% used fixed doses of subcutaneous heparin. Because the incidences of DVT and PE in THR patients are high, all of these patients should receive prophylaxis. The standard LDH regimen, effective for patients receiving gynecologic, general, and most orthopedic procedures, is ineffective for THR patients. The available prophylactic methods proven to reduce DVT and PE in THR patients are adjusted-dose subcutaneous heparin, dextrans, low-dose warfarin, and EPC. Comparative studies have not clearly demonstrated superiority of any one method. However, low-dose warfarin may offer better protection in very high-risk patients. External pneumatic compression offers protection without increasing bleeding risks. Dextrans are effective but are expensive and may be associated with significant side effects. Adjusted-dose subcutaneous heparin is also effective but is cumbersome to use. Low-molecular-weight heparin appears to be a promising alternative. We recommend the routine use of EPC and reserve low-dose warfarin fro patients with histories of prior thromboembolic or venous disease.(ABSTRACT TRUNCATED AT 250 WORDS)

External pneumatic compression stockings: Inadequate prophylexis of proximal DVT following total hip arthroplasty

External pneumatic compression stockings: Inadequate prophylexis of proximal DVT following total hip arthroplasty

Influence of prophylaxis on proximal venous thrombus formation after total hip arthroplasty

Deep vein thrombosis (DVT) is the most frequent complication after total hip arthroplasty, and proximal DVT is more likely to produce clinical pulmonary emboli than distal DVT. The authors have assessed the incidence and anatomic location of phlebographically proven fresh DVT following total hip arthroplasty in 855 patients over 39 years of age. Eight different regimens (2 warfarin, 3 aspirin, 1 dextran, 1 external pneumatic compression, and 1 dextran combined with external pneumatic compression) were evaluated and compared with an historical placebo control group from the same institution. No significant difference ( P<.05) existed in proximal DVT incidence between the placebo group and any of the three aspirin groups, the dextran group, the external pneumatic compression group, or the dextran combined with external pneumatic compression group. In contrast, warfarin, given both in traditional and low-dose regimens, provided a significant reduction in proximal DVT compared with the placebo group ( P<.001; statistical power, 0.84 and 0.99, respectively). The low-dose regimen had 10 times fewer bleeding complications than the traditional regimen. All prophylaxis regimens should be evaluated for both proximal and distal DVT formation, as well as for overall incidence. Low-dose warfarin offers the best protection against proximal thrombi of the agents studied, and it is also safer than traditional dosages of warfarin.

Long-term results of compression treatment for lymphedema

Although numerous operations have been devised for lymphedema, most surgeons manage this vexing condition by nonsurgical means. Previous studies by us showed that high-pressure (90 to 100 torr) sequential external pneumatic compression (SEP) reduced both limb girth and volume in a lymphedematous extremity. To assess the long-term effects of a program entailing (1) SEP, (2) elastic compression stockings to maintain the post-SEP girth, and (3) daily skin care, we reviewed the long-term courses of 49 patients managed by one surgeon. Limb girths measured at nine levels on the limb were obtained serially in follow-up (mean 25 months) by an independent observer to provide an objective response to therapy. The relative reduction in lymphedematous tissue was determined by the difference between the pretreatment, postacute treatment, and long-term treatment girths at nine points in the limb. In long-term follow-up, 26 of the patients maintained a full response (reduction at > 3 levels), whereas 10 maintained a partial response (reduction at < or = 3 levels). At late follow-up, calf and ankle girths were reduced by an absolute value of 5.37 +/- 1.01 and 4.63 +/- 0.88 cm in the full-response group and 5.43 +/- 1.58 and 3.98 +/- 1.18 cm in the partial-response group over pretreatment measurements. The degree of subcutaneous fibrosis in relationship to the duration of the edema appeared to influence results greatly. The treatment of lymphedema with SEP and compression stockings is associated with long-term maintenance of reduced limb girth in 90% of patients.