External Pneumatic Compression Research Articles

Acute Effects of External Pneumatic Compression on Peripheral and Central Hemodynamics

Use of external pneumatic compression (EPC) to improve recovery after exercise is increasing. However, the acute hemodynamic effects of EPC have not been determined. The purpose of this study was to investigate the acute effects of EPC on the aortic pressure waveform (AoPW) during EPC therapy. Twenty (n=20) young participants (23.5±3.9 years) were included in this study. Analysis of the AoPW was evaluated continuously using applanation tonometry before, during, and after a single 1‐hr therapeutic session of EPC. A sequential EPC device was employed with target inflation pressures of ~100 mmHg of compression. Peripheral systolic blood pressure was increased by 5.8±1.3 mmHg during EPC and remained elevated 10 minutes post treatment, p<0.05. Aortic systolic blood pressure was increased by 5.9±1.1 mmHg during EPC and remained elevated 10 minutes post treatment, p<0.01. Both peripheral and aortic diastolic blood pressure were significantly increased by 5.1±0.9 and 4.8±0.9 mmHg, respectively, during EPC and remained elevated 10 minutes post treatment, p<0.05. Peripheral and aortic mean arterial pressure were increased by 4.2±1.0 and 4.3±1.1 mmHg, respectively, during EPC and remained elevated 10 minutes post treatment when compared to baseline values, p<0.05. EPC at target inflation pressures of 100mmHg increases total peripheral resistance to lower limb blood flow which results in increases in peripheral and central blood pressures during therapy and persists at least 10 minutes post treatment.

Acute Whole‐Leg Pneumatic Compression Alters Nerve Growth Factor mRNA and Akt‐mTOR Signaling in Human Skeletal Muscle

We sought to investigate recovery markers following a single bout of whole‐leg external pneumatic compression (EPC). Post‐prandial (> 4 hours) and rested participants (N=12) were treated with 1‐h of whole‐leg EPC using a peristaltic pulse dynamic compression device with target inflation pressures of ~70 mmHg. Vastus lateralis muscle biopsies were obtained prior to, 1 h and 4 h following EPC. Samples were analyzed for select mRNA markers of angiogenesis, growth factors, metabolic, and pro‐inflammatory markers as well as various phospho (p)‐proteins related to Akt‐mTOR, Jak‐Stat, and apoptosis signaling. Nerve growth factor (NGF) mRNA exhibited a trend towards up‐regulation from pre to 4 h post compression (p = 0.06), though there was an up‐regulation from 1 h to 4 h post‐EPC (p = 0.04). From pre to 1 h post‐EPC there was a decrease in p‐Bad (Ser112) (p = 0.05) which was still significantly decreased 4 h post‐EPC (p=0.004) phospho‐Stat1 (Tyr701) decreased from 1 h to 4 h post‐EPC (p = 0.03). P‐Akt (Ser473) also significantly decreased from 1 h to 4 h post‐EPC (p = 0.04). P‐ribosomal protein S6 (Ser235/236) was transiently increased 1 h post‐EPC (p = 0.02). P‐p70s6k (Thr389) was decreased 4 h post‐EPC (p = 0.02). P‐proline rich protein‐40 (Thr246) was also significantly decreased 4 h post‐EPC (p = 0.02). These data indicate that an acute bout of EPC up regulates NGF mRNA as well as affecting Akt‐mTOR signaling substrates. Further investigations should employ exercise‐related stimuli in conjunction with EPC to investigate potential recovery‐enhancing effects.

Acute Effects of an External Pneumatic Compression Device on Local and Systemic Resistance Vessel Reactivity and Limb Blood Flow

High pressure external pneumatic compression (e.g. EECP) has been shown to have marked benefits on vascular reactivity and biology. However it is expensive, uncomfortable, and not easily accessible. Alternatively, low pressure EPC is commercially available, does not require medical supervision, and is low risk.PurposeThe purpose of this study was to determine the acute effects of low pressure EPC on resting limb blood flow and resistance vessel reactivity in compressed and non‐compressed limbs of healthy young subjects.MethodsTen (n=10) apparently healthy subjects (aged 27.0 ± 10.2 years) were enrolled in this randomized, crossover design study. Subjects reported in the morning, fasted, for two visits separated by at least 24‐hours. Prior to and immediately following application of EPC or sham for 60 minutes, forearm (FBF) and calf blood flow (CBF) were evaluated at baseline and during 3 minutes of reactive hyperemia (RH) using venous occlusion plethysmography. A peristaltic pulse dynamic compression device was employed for EPC treatment with target inflation pressures of ~70 mmHg applied to the lower limbs.ResultsEPC significantly improved peak CBF, but no differences in resting FBF, peak FBF, resting CBF, total CBF and total FBF were observed. imageConclusionsEPC significantly improves acute resistance vascular reactivity in compressed limbs, but not non‐compressed limbs, following 60 minutes of treatment. Therefore, application of low pressure EPC may be efficacious in situations where local alterations of resistance vessel reactivity is desirable.Partial support for this study was provided by the Quinnipiac University Interdisciplinary Program for Research & Scholarship and by NormaTec (Newton Centre, MA)

Letter to the Editor: Editor’s Spotlight/Take 5: CT Pulmonary Angiography After Total Joint Arthroplasty: Overdiagnosis and Iatrogenic Harm?

Your Editor’s Spotlight/Take 5 [3] on the issues involved in the diagnosis, overdiagnosis, and management of pulmonary embolism following THA was fascinating. It prompts me to toss two concepts into the discussion. In reality, there is no specific treatment for pulmonary embolism, except in those rare cases of major compromise of pulmonary function or cardiovascular function. We do not treat the pulmonary embolism that has already occurred. The management is directed against the next embolism. It is a common misconception that we are “treating” the existing embolism. In most cases, we simply let nature take its course with that embolus, and hope to prevent the next one. A perfect example of this concept is the placement of a filter after a pulmonary embolism. The filter will have nothing to do with the existing pulmonary embolism, but is aimed to prevent another one. With that concept in mind, the obvious next question is, “Which emboli need to be treated?” While there is no answer to that question, and there probably never will be until we can identify the presence of existing clots so as to really evaluate the risk of the next embolus, having some idea of the true incidence of asymptomatic emboli would be helpful. We performed that study in patients after total hip arthroplasty [2]. Since the radiation burden of the C15O2 scans was so low, we got IRB permission to do them every 4 days. If that test was positive, we followed up with a ventilation/perfusion (VQ) scan; when a patient had a positive VQ scan, we confirmed the diagnosis using pulmonary angiography. Even though the patients were on one form of prophylaxis or another (aspirin, dextran plus external pneumatic compression, or warfarin), 23% had pulmonary embolism on angiography. Approximately 83% of those with a positive angiography were in asymptomatic patients. Our study is at the opposite end of the spectrum from the study by D’Apuzzo and colleagues [1]. They assessed data from more than 8,000 patient records, while we studied intently only 73 patients. Nevertheless, I see no reason to think that our experience was unique, although today patients mobilize after surgery more quickly. Even with that exception, our study was representative of the mobilization protocols of that time, and thus of thousands of patients over those decades. Thus, it clearly identified the very common occurrence of asymptomatic pulmonary embolism after THA. If we make the reasonable assumption that similar events were occurring in other representative groups of THA patients, then—in a way similar to the realization that deep vein thrombosis was 50% or so rather that 10 or 15% after THA in unprotected patients—asymptomatic pulmonary embolism were common then, and are likely to still be common now. In many cases, those asymptomatic pulmonary emboli were never identified, and so were of no clinical significance. As an aside, when I published my first paper on reducing deep vein thrombosis in hip patients 50 years ago, little did I recognize that we would still be in pursuit of these issues five decades later!

External pneumatic compression device prevents fainting in standing weight-bearing MRI: a cohort study

To investigate if a peristaltic external pneumatic compression device attached to the legs, while scanning, can reduce a substantial risk of fainting in standing weight-bearing magnetic resonance imaging (MRI). This study comprised all patients with low back pain referred to standing MRI of the lumbar spine, using a 0.25-T open G-Scanner, from June 2011 to April 2012. The standing MRI protocol included a sagittal TSE T2w and an axial GRE T2w sequence giving a total scan time of 17min. The first patients were scanned standing without a device (control group), and then from January to April 2012 the patients were scanned in the standing position using an external pneumatic compression device, attached to the legs (experimental group). One hundred and forty-nine patients (mean age 42.5, standard deviation 12.5, and range 20-77years) were included and scanned standing. No significant difference in age (p = 0.51) or gender (p = 0.47) was observed between the control group (n = 86) and the experimental group (n = 63). Sixteen patients (19%) fainted in the control group during the standing MRI scan, compared to one patient (2%) in the experimental group where the pneumatic compression device was applied. The difference between groups was highly significant (p = 0.001; Fisher's exact test), with an OR = 0.071 (exact 95%CI: 0.002 to 0.486) for the pneumatic compression device. A substantial risk of fainting during standing MRI was almost eliminated by using an external peristaltic pneumatic compression device.

The Future Landscape of Anticoagulation Management

Back then we had warfarin and unfractionated heparin, and we thought that we knew all we needed to know in order to manage those anticoagulants optimally. We were wrong then, and we are probably more subtly wrong now. But I have been asked to comment on what I anticipate the future holds for anticoagulation management and the role of pharmacy in it. Because of the nature of progress, I realize that the more detailed my vision of the future, the greater is the certainty that that vision will be wrong. First, I will focus on what I believe is needed in the near term and then address how I imagine patient selfmonitoring, novel oral anticoagulants, and pharmacogenomics—three topics discussed in this special issue of Pharmacotherapy that reflect areas of change—will affect the future of anticoagulation management.

The incidence of deep vein thrombosis detected by routine surveillance ultrasound in neurosurgery patients receiving dual modality prophylaxis

The optimal method of thromboprophylaxis and the value of screening ultrasonography for detection of deep venous thrombosis (DVT) in neurosurgery patients remains unclear. The goal of this study was to determine the incidence of DVT in neurosurgical patients who, by hospital protocol, receive surveillance ultrasonography of the lower extremities twice weekly, in addition to prophylaxis with unfractionated heparin and external pneumatic compression sleeves. A retrospective review of 7,298 ultrasound studies carried out on 2,593 patients over 4years at a university neurosurgical hospital was conducted. There was a 7.4% incidence of proximal lower extremity DVT and a 9.7% total incidence including distal DVT. A greater number of distal DVTs were detected with the implementation of whole-leg ultrasonography in the last 2years of observation. Chart review of 237 patients diagnosed with DVT demonstrated an admitting diagnosis of subarachnoid hemorrhage in nearly half of the patients. The median hospital length of stay for DVT patients was 18days. Institutional control data demonstrated non-ruptured aneurysm and cerebrovascular anomalies to be the leading reason for admission, followed closely by subarachnoid hemorrhage. The hospital protocol of biweekly screening ultrasound and dual modality prophylaxis for neurosurgery patients resulted in a proximal DVT incidence consistent with that demonstrated by previous studies of standardized dual modality prophylaxis, and higher than that demonstrated in previous studies that employed ultrasound screening protocols.

Acute Effects Of Cyclic Limb Compressions on mRNA Expression Of Angiogenic Factors In Skeletal Muscle

Muscle contraction and therapeutic application of external pneumatic limb compression produces cyclic deformations and changes in shear-stress in the vasculature embedded in skeletal muscle. These mechanical forces are well known stimuli for angiogenic growth factor release in skeletal muscle. PURPOSE: We tested the hypothesis that acute application (150 min) of cyclic leg compressions in a rat model up-regulates factors involved in angiogenesis in skeletal muscle. METHODS: To explore the impact of different pressures and frequency of compressions, rats were divided into 4 groups: 120mmHg (2s inflation/2s deflation), 200mmHg (2s inflation/2s cuff deflation), 120mmHg (4s inflation/16s deflation) and control (no intervention). Intermittent pneumatic compressions were achieved by cyclically inflating/deflating a small cuff wrapped around the rat calf using a cuff inflator unit (Hokanson E20, Bellevue, WA, USA). Blood flow and leg oxygenation (Study 1, n=17) and the mRNA expression (RT-PCR) of angiogenic mediators in the rat tibialis anterior (TA) muscle (Study 2, n=16) were assessed after a single bout of IPC. RESULTS: In all three groups exposed to the intervention, a modest hyperemia (∼37% above baseline) between compressions and a slight, non-significant increase in leg oxygen consumption (∼30%) was observed during IPC. Compared to the control group, vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) mRNA increased significantly (p<0.05) only in the rats exposed to the higher frequency on compressions (2s/2s). CONCLUSIONS: These findings show that application of intermittent leg compressions and the accompanying stretch/deformation of the vasculature as well as changes in leg hemodynamics augment the mRNA content of key angiogenic factors in skeletal muscle. Importantly, the magnitude of changes in mRNA expression appeared to be modulated by the frequency of compressions, such that a higher frequency evoked the most robust changes in VEGF and MCP-1. Support: NIH Grants RR-18276, HL-36088 and ACSM Foundation Research Grant.

State-of-the-art thrombosis prevention and treatment

Thrombosis is the leading cause of death in developed countries, with arterial thrombosis presenting as myocardial infarction, stroke or peripheral arterial occlusion. Venous thromboembolism (VTE) is a major cause of mortality worldwide, despite some variations in prevalence of the disease [1]. While the incidence of VTE increases with aging, it is the leading cause of vascular morbidity in young adults. A multitude of risk factors can contribute to presentation of VTE [2]. This includes transient risk factors such as trauma, surgery, immobilization, long-haul flights, acute medical illness, hormonal therapy and pregnancy. Long-standing risk factors include chronic conditions such as congestive heart failure, chronic lung disease, inflammatory bowel disease and nephrotic syndrome. The discovery of thrombophilic risk factors opened a new era of genetic assessment of the predisposition for VTE with potential ability for better definition of the risk associated with transient risk factors. For example, hormonal therapy in women with thrombophilic risk factors, such as Factor V Leiden and the prothrombin gene polymorphism, multiply the risk for VTE [3]. While testing for thrombophilia is appealing, wider application has been hampered by equivocal cost-effectiveness analysis. A screening test for thrombophilia would be useful, and global assays such as the Protein C Global have been suggested in this regard [4]. In general, VTE is preventable by application of prophylactic measures. Applying early mobilization and physical measures such as elastic stockings and external pneumatic compression devices is useful. The current pharmacological approach is based on unfractionated, low-molecular-weight heparins (LMWH) and fondaparinux. Vitamin K

Influence of Intermittent Pneumatic Compression Devices on Non-Invasive Blood Pressure Measurement of the Ankle

It is rapidly becoming the standard of care to employ the perioperative use of intermittent pneumatic compression (IPC) devices on the lower leg to prevent the development of deep venous thrombosis. There are instances when the anesthesiologist must apply a blood pressure cuff to the ankle in order to obtain a blood pressure reading. The purpose of this study is to determine the influence of IPC devices on non-invasive blood pressure measurements of the ankle. We utilized the Flowtron Excel External Pneumatic Compression System Model AC550 and the Datascope Passport non-invasive blood pressure monitor Model EL, in 50 healthy volunteers ranging in ages from 23 to 35 who were free of systemic disease. The IPC devices were applied to both lower extremities and sequentially inflated. All blood pressure measurements (systolic, diastolic, and mean arterial pressure) were taken with the volunteer in the supine position, obtained in triplicate and then averaged. Blood pressure measurements were obtained at four time periods: 1) when the IPC device was placed over the ankle blood pressure cuff but not inflated (control) 2) 15 s prior to inflation of the IPC device 3) at inflation of the IPC device and 4) 15 s after the beginning of inflation of the IPC device. The difference between the averaged blood pressures and the control blood pressures were calculated. The resulting values were then converted to absolute values. The averaged absolute values were analyzed using ANOVA for repeated (paired) data. No statistical significant difference was shown between the control blood pressure measurements and any of the three sets of blood pressure measurements relative to IPC device inflation; 15 s prior, at onset, and 15 s after inflation. The p-values for systolic, diastolic, and MAP were respectively 0.872, 0.645 and 0.522. With these p-values, the power tests for each were >0.80. The IPC device had no significant impact on non-invasive blood pressure measurement of the ankle in our study.

Defining practice patterns in Gynecologic Oncology to prevent pulmonary embolism and deep venous thrombosis

Objective. The goal of venous thromboembolism (VTE) prophylaxis is to reduce the morbidity and mortality associated with the development of a deep venous thrombosis (DVT) or pulmonary embolism (PE). Because women with gynecologic cancers are at high risk to develop VTE, we sought to determine the present practice patterns of gynecologic oncologists regarding their use of VTE prophylaxis. Methods. 1073 members of the Society of Gynecologic Oncologists (SGO) were mailed surveys that asked about preferred methods to prevent the development of VTE after gynecologic oncology surgery. Data were collected by online member entry and return mail. Frequency distributions were calculated and nonparametric test used for comparisons. Results. 343/1073 (34%) of SGO members and fellows responded. 142/343 (42%) preferred double prophylaxis consisting of external pneumatic compression (EPC) and an anticoagulant while 41% ( n = 141) preferred EPC with no additional anticoagulation. Of respondents choosing any anticoagulant, 40% preferred Enoxaparin pre- and/or postoperatively. Ovarian cancer patients were perceived by respondents to have the highest risk of developing a postoperative PE. Conclusions. Most respondents agree that women with gynecologic cancers undergoing major surgery should receive VTE prophylaxis, though there is not agreement as to which method is optimal. While 42% of members preferred double prophylaxis, 41% chose no additional measures other than EPC. Randomized studies in gynecologic oncology should be initiated in the United States to determine the optimal practice pattern.

Transfusion utilization during adnexal or peritoneal cancer surgery: Effects on symptomatic venous thromboembolism and survival

Objective. To determine whether perioperative packed red blood cell (PRBC) and fresh frozen plasma (FFP) transfusions during ovarian, tubal, or peritoneal cancer surgery increase the risk of symptomatic postoperative venous thromboembolism (VTE) and adversely affect overall survival. Methods. We conducted a retrospective review of all cases of surgical exploration for resection of stage IIIC-IV adnexal/peritoneal cancer between November 1998 and May 2002 at Memorial Sloan-Kettering Cancer Center. Patients with a history of prior or active preoperative VTE were excluded. Routine intraoperative and postoperative VTE prophylaxis including lower extremity external pneumatic compression with or without postoperative subcutaneous heparin was utilized in all cases. Symptomatic postoperative VTE was diagnosed by lower extremity Doppler or computerized tomography (excluding cases with only ovarian vein thrombosis). Clinical parameters were examined by a logistic regression analysis to identify independent prognostic predictors of postoperative symptomatic VTE, which occurred within 30 days of surgery. Survival was calculated using the Kaplan–Meier method. Results. In all, 174 patients underwent exploratory surgery, and 6 (3.4%) were excluded due to active or prior history of VTE. Of the remaining 168 patients, 71 (42%) received at least one perioperative transfusion of PRBC or FFP. Postoperative VTE was documented in 5 of 46 (11%) patients who received a postoperative transfusion compared to 3 of 122 (2.5%) patients who did not ( P = 0.04; odds ratio, 4.8); moreover, VTE was noted in 3:16 (19%) patients who received postoperative FFP compared to 5:152 (3.3%) patients who did not ( P = 0.01, odds ratio of 6.78). Age, stage, body mass index, length of the operation, blood loss, presence of ascites, volume of ascites, residual disease status, preoperative hemoglobin level and coagulation profile were not associated with increased risk for VTE. When survival results were stratified by transfusion utilization and controlling for optimal debulking status, perioperative transfusions had no apparent effect on overall survival. Conclusion. In women with stage IIIC-V disease, postoperative blood product transfusions particularly FFP were associated with increased risk of DVT and PE, but transfusions had no impact on overall survival.

Importance and Advantages of Intermittent External Pneumatic Compression Therapy in Venous Stasis Ulceration

Venous ulcers are seen following postthrombophlebitic syndrome with venous insufficiency and can begin as a result of minor trauma. In this retrospective study the authors examined the value of external intermittent pneumatic compression therapy in chronic venous ulcers. Results in 1,250 patients with postthrombophlebitic syndromes, 235 of these patients with leg ulcers, revealed that this modality of therapy shortens the therapy duration, lowers the total therapy cost, and hastens the return to active life in comparison to the classical therapy with compression stockings and antiaggregant or low-dose oral anticoagulant therapy. In the light of their findings they propose the wider use of this adjuvant therapy.

Efficacy of mechanical prophylaxis for venous thromboembolism in patients with brain tumors

Patients with brain tumors are at considerable risk for the formation of venous thromboemboli. One method of preventing these complications is mechanical prophylaxis in which an external pneumatic compression device and graduated elastic compression stockings are used. Evidence indicates that these devices prevent deep venous thrombosis (DVT) and pulmonary embolism (PE) by limiting venous stasis and increasing fibrinolytic activity at both the local and systemic levels. The authors present evidence for the occurrence of both mechanisms and discuss the use of mechanical compression in the setting of surgery for brain tumors. They also present data proving the efficacy of these devices in patients who undergo craniotomy with motor mapping for resection of glioma and in whom the contralateral leg receives no prophylaxis. Finally, they comment on the use of anticoagulation therapy both in addition to and in place of mechanical prophylaxis.

Cost-effectiveness of combination thromboembolism prophylaxis in gynecologic oncology surgery

Objective. To compare the cost-effectiveness of external pneumatic compression devices with and without the addition of low-molecular-weight heparin for the prevention of deep vein thrombosis in high-risk surgical patients with gynecologic cancer. Methods. A Markov decision analytic model was used to estimate the costs and outcomes associated with the prophylactic use of external pneumatic compression with and without low-molecular-weight heparin in patients undergoing gynecologic surgery. We estimated cost per fatal pulmonary embolus prevented, cost per deep vein thrombus prevented, and cost per life-year saved. Probability estimates for various outcomes and efficacies were obtained from the literature, using data specific for gynecologic surgery patients when available. Results. In the base case scenario, cost-effectiveness estimates for combination prophylaxis varied from $10,091 per life-year saved for a 35-year-old patient with IB cervix cancer patient to $50,181 for a 65-year-old patient with stage IIIC ovarian cancer, costs within the $50,000–65,000 per life-year saved threshold considered to be cost-effective. Combination prophylaxis appeared to be cost-effective in gynecologic oncology patients as long as the risk of perioperative thromboembolism using this method of prevention was less than or equal to 4%. Sensitivity analysis indicated that variation of the marginal cost of low-molecular-weight heparin and the marginal effectiveness to extremes did not change the conclusions of the statistical model. Conclusion. The use of combination therapy external pneumatic compression is estimated to be cost-effective for high-risk gynecologic oncology patients undergoing surgery. Clinical trials to determine the efficacy of perioperative combination therapy in gynecologic surgery are justified.

A multimodality regimen for deep venous thrombosis prophylaxis in total knee arthroplasty

Data indicate that deep venous thrombosis (DVT) occurs at the time of knee arthroplasty. Nevertheless, literature concerning DVT prophylaxis has only recently addressed this contention. This prospective study evaluated the efficacy of a perioperative prophylactic regimen. Between January 1996 and June 2001, 1,308 knees (964 surgeries) underwent total knee arthroplasty. Patients were treated routinely with intraoperative heparin (1000 units intravenous push before inflation of the tourniquet and 500 units at deflation), hypotensive epidural anesthesia (MAP 70-90), external pneumatic compression boots, and aspirin (325 mg, PO, BID for 6 weeks). Duplex venous ultrasonography was performed before discharge. DVT was detected in 4% of cases (1% proximal and 3% distal). Bleeding complications occurred in 1%, and perioperative medical complications occurred in 12%. Copyright 2003, Elsevier Science (USA). All rights reserved.

The effect of external pneumatic compression on regional fibrinolysis in a prospective randomized trial

External pneumatic compression devices (EPC) prevent deep venous thrombosis (DVT) by reducing lower extremity venous stasis. Early studies suggested they also enhance fibrinolytic activity; however, in a recent study, EPC had no effect on systemic fibrinolysis in patients undergoing abdominal surgery. The hypothesis of this study was that EPCs enhance regional fibrinolysis in these subjects. Forty-five patients (44 male, one female; mean age, 67 years) undergoing major abdominal surgery (35 bowel procedures, 10 aortic reconstructions) were prospectively randomized to one of three groups for DVT prophylaxis: subcutaneous heparin injections (HEP), thigh-length sequential EPC devices (EPC), or both (HEP+EPC). Prophylaxis was begun immediately before surgical incision and continued until postoperative day 5 or patient discharge. Venous blood samples were collected from the common femoral vein for measurement of regional fibrinolysis after induction of anesthesia but before initiation of prophylaxis, and on postoperative days 1, 3, and 5. A baseline sample was collected the day before surgery. Fibrinolysis was quantified with measurement of the activities of tissue plasminogen activator (tPA; the activator of fibrinolysis) and its inhibitor plasminogen activator inhibitor-1 (PAI-1) with amidolytic technique. tPA activity in all groups was normal at baseline; baseline PAI-1 activity was elevated. Within each prophylaxis group, no significant changes occurred in either tPA or PAI-1 activities after induction of anesthesia or after surgery compared with before surgery (P >.05, analysis of variance with repeated measures). No changes occurred between postoperative samples and after anesthesia within each group. No significant enhancement of fibrinolysis, manifested as either increased tPA activity or decreased PAI-1 activity, occurred in either EPC group compared with the HEP group at any time point (P >.05, analysis of variance with repeated measures). No differences were noted when surgery was performed for malignant disease versus nonmalignant disease. In this study, enhanced regional fibrinolysis in the lower extremities could not be detected with the use of EPCs, as measured with tPA and PAI-1 activity in common femoral venous blood samples. EPC devices do not appear to prevent DVT with fibrinolytic enhancement; effective and safe prophylaxis is provided only when the devices are used in a manner that reduces lower extremity venous stasis.

Preference and Compliance in Postoperative Thromboembolism Prophylaxis Among Gynecologic Oncology Patients

In Brief OBJECTIVE To compare low molecular weight heparin and external pneumatic compression in terms of patient preference and compliance to determine if either of these two methods is superior in postoperative thromboembolism prophylaxis of gynecologic oncology patients. METHODS A total of 211 patients undergoing major surgery for a suspected gynecologic malignancy were randomized to receive thromboembolism prophylaxis with either external pneumatic compression or low molecular weight heparin. Surveys regarding thromboembolism prophylaxis were completed by patients before surgery and approximately 7 days postoperatively. Patient preferences as well as reasons for patient dissatisfaction with prophylactic methods were elicited in the questionnaires. In addition, patient compliance with prophylaxis was recorded twice a day during hospitalization. Patients were not considered to be compliant with prophylaxis if the external pneumatic compression device was not functioning properly or if the administration of low molecular weight heparin was not given in a timely manner. RESULTS The majority of patients were satisfied with the prophylactic method that they received to the extent that they would prefer the treatment they received to one they had not necessarily experienced. The postoperative preferences of 78% of patients receiving low molecular weight heparin and 74% of those wearing external pneumatic compression corresponded to what the patients actually received as a method of thromboembolism prevention. Patient compliance with prophylaxis was noted to be inadequate in ten of 104 (9.6%) patients receiving external pneumatic compression and seven of 103 (6.8%) patients receiving low molecular weight heparin. CONCLUSION Pneumatic compression and low molecular weight heparin are similar both in terms of patient preference and compliance among gynecologic oncology patients receiving postoperative thromboembolism prophylaxis. Pneumatic compression and low molecular weight heparin are similar both in terms of patient preference and compliance among gynecologic oncology patients receiving postoperative thromboembolism prophylaxis.

Preference and compliance in postoperative thromboembolism prophylaxis among gynecologic oncology patients

OBJECTIVE: To compare low molecular weight heparin and external pneumatic compression in terms of patient preference and compliance to determine if either of these two methods is superior in postoperative thromboembolism prophylaxis of gynecologic oncology patients. METHODS: A total of 211 patients undergoing major surgery for a suspected gynecologic malignancy were randomized to receive thromboembolism prophylaxis with either external pneumatic compression or low molecular weight heparin. Surveys regarding thromboembolism prophylaxis were completed by patients before surgery and approximately 7 days postoperatively. Patient preferences as well as reasons for patient dissatisfaction with prophylactic methods were elicited in the questionnaires. In addition, patient compliance with prophylaxis was recorded twice a day during hospitalization. Patients were not considered to be compliant with prophylaxis if the external pneumatic compression device was not functioning properly or if the administration of low molecular weight heparin was not given in a timely manner. RESULTS: The majority of patients were satisfied with the prophylactic method that they received to the extent that they would prefer the treatment they received to one they had not necessarily experienced. The postoperative preferences of 78% of patients receiving low molecular weight heparin and 74% of those wearing external pneumatic compression corresponded to what the patients actually received as a method of thromboembolism prevention. Patient compliance with prophylaxis was noted to be inadequate in ten of 104 (9.6%) patients receiving external pneumatic compression and seven of 103 (6.8%) patients receiving low molecular weight heparin. CONCLUSION: Pneumatic compression and low molecular weight heparin are similar both in terms of patient preference and compliance among gynecologic oncology patients receiving postoperative thromboembolism prophylaxis.

Endothelial nitric oxide production during in vitro simulation of external limb compression.

External pneumatic compression (EPC) is effective in preventing deep vein thrombosis (DVT) and is thought to alter endothelial thromboresistant properties. We investigated the effect of EPC on changes in nitric oxide (NO), a critical mediator in the regulation of vasomotor and platelet function. An in vitro cell culture system was developed to simulate flow and vessel collapse conditions under EPC. Human umbilical vein endothelial cells were cultured and subjected to tube compression (C), pulsatile flow (F), or a combination of the two (FC). NO production and endothelial nitric oxide synthase (eNOS) mRNA expression were measured. The data demonstrate that in the F and FC groups, there is a rapid release of NO followed by a sustained increase. NO production levels in the F and FC groups were almost identical, whereas the C group produced the same low amount of NO as the control group. Conditions F and FC also upregulate eNOS mRNA expression by a factor of 2.08 +/- 0.25 and 2.11 +/- 0.21, respectively, at 6 h. Experiments with different modes of EPC show that NO production and eNOS mRNA expression respond to different time cycles of compression. These results implicate enhanced NO release as a potentially important factor in the prevention of DVT.