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.     

The rate of PD catheter complication does not increase with simultaneous abdominal surgery

Introduction

Children with kidney failure requiring PD catheter placement often require additional intraabdominal surgery. However, the risk of complication related to simultaneous abdominal surgery at time of catheter placement is unknown.

尿激酶型纤溶酶原激活物及其受体高表达增强血管收缩性重塑和内膜增生的研究

目的　探讨血管壁中尿激酶型纤溶酶原激活物 (uPA)和其受体 (uPAR)表达与血管收缩性重塑和内膜增生的相关性。方法　建立兔髂动脉粥样硬化再狭窄模型 ,比较内膜和中膜层的uPA、uPAR表达及其与内膜面积和血管重塑指数的相关性。结果　内膜层uPA、uPAR的抗原和mRNA表达明显强于中膜层 (P <0 .0 1) ,血管壁内膜uPA、uPAR的抗原和mRNA表达水平与血管重塑指数呈负相关 (r =-0 .870 0 7,P =0 .0 10 9;r =-0 .860 3 8,P =0 .0 13 0和r =-0 .845 5 5 ,P =0 .0 165 ,r =-0 .862 40 ,P =0 .0 12 5 ) ,与内膜面积呈正相关 (r=0 .92 0 0 0 ,P =0 .0 3 3 0 ;r=0 .90 772 ,P =0 .0 0 47和r=0 .92 14 9,P =0 .0 0 3 2 ;r =0 .90 614 ,P =0 .0 0 49) ,血管重塑指数和血管内膜面积与中膜uPA、uPAR表达无明显相关性。结论　内膜层uPA、uPAR高表达增强了血管重建后血管壁收缩性重塑和内膜增生。     

Screening for abdominal aortic aneurysms does not increase psychological morbidity.

Screening can lead to harmful psychological effects in the screened population--an argument used against abdominal aortic aneurysm (AAA) screening. However, there is no evidence for this in AAA screening. We applied the Hospital Anxiety and Depression Scale (HADS) to a group of men undergoing screening for AAA. The HADS questionnaire was completed by subjects found not to have AAA, subjects with known small aneurysms attending for follow-up scans, subjects with known AAA on waiting lists for surgery, and controls not involved in the screening programme. The groups were well matched for age and the number of additional diseases. There was no significant difference in the distribution of patients for anxiety and depression according to the HADS questionnaire (chi 2 test, P > 0.1). The results from this study suggest that AAA screening does not increase anxiety or depression in the screened subjects--contrary to the argument put forward against screening for this condition.     

The study of plasminogen activator in renal cell carcinoma with special remarks on urokinase type plasminogen activator

Plasminogen activators (PA) have been reported to be associated with fibrinolysis. The amounts of PA in urine, plasma, and tissues of patients with renal cell carcinoma were determined by measuring the amounts of two kinds of antigens, urokinase type (u-PA) antigen and tissue type (t-PA) antigen, by highly sensitive enzyme-immunoassay. The u-PA antigen level in urine showed neither daily variation nor age-relationship. It was, however, significantly higher (164.2 +/- 93.5 x 10(2) U/gCr) in patients with renal cell carcinoma than in healthy subjects (56.8 +/- 22.4 x 10(2) U/gCr) (p less than 0.01). The amount of u-PA antigen in urine tended to be higher in patients with high grade or stage cancer than in those with cancer of low grade or stage, though not statistically significant. The u-PA antigen content in tissues appeared elevated in tumors (8.90 +/- 6.00 x 10(-1) U/g wet tissue) in comparison to normal renal cortex and medulla. However, the difference was not significant, as the cancer samples consisted of various tissue components including necrotic or hemorrhagic tissue in addition to cancer cells. Although the t-PA antigen content in urine was too immeasurably small in 29% cases by the present method, there was no significant difference between patients with renal cell carcinoma and healthy subjects. The plasma level of t-PA antigen tended to be elevated in renal cell carcinoma group (7.87 +/- 5.60 U/ml) compared to the control group (5.7 +/- 2.19 U/ml), but no significant difference was present between them.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormal levels of urokinase plasminogen activator protein and tissue plasminogen activator activity in human aortic aneurysms.

OBJECTIVE: To measure the concentrations and activities of plasminogen activators and plasminogen activator inhibitors in human abdominal aneurysms. DESIGN: Laboratory study. SETTING: University hospital, Sweden. MATERIAL: Biopsy specimens from 12 abdominal aortic aneurysms and 8 normal aortas (controls). INTRERVENTIONS: Tissues were homogenised and eluted. The supernatants were assayed for antigens of tissue and urokinase plasminogen activator and plasminogen activator inhibitor 1 and 2. The activities of tissue plasminogen activator and plasminogen activator inhibitor-1 were assayed by ELISA. Frozen sections were immunostained for tissue and urokinase plasminogen activators and for plasminogen activator inhibitor-1. MAIN OUTCOME MEASURES: Concentrations and activities of these activators and inhibitors. RESULTS: The concentration of urokinase plasminogen activator antigen was higher in aneurysmal walls than in normal aortas; it was detected immunohistochemically in aneurysmal but not in normal aortas. The concentration (and the detection immunohistochemically) of tissue plasminogen activator was equal in aneurysmal and normal aortas, but its activity was reduced in the aneurysmal wall. Plasminogen activator inhibitor-1 did not differ significantly between the groups. CONCLUSIONS: Urokinase plasminogen activator may be responsible for the digestion of the media of the aorta and the development of an aneurysm. Reduced activity of tissue plasminogen activator may be responsible for thrombosis in the aneurysm.     

Release of urokinase plasminogen activator receptor during urosepsis and endotoxemia

BACKGROUND: The urokinase receptor (uPAR; CD87) is a multifunctional molecule involved in fibrinolysis, in proteolysis, in renal tubular functions, and in migration and adhesion of inflammatory cells to the site of infection. METHODS: To gain insight into systemic and local release of uPAR and into its regulation during urosepsis, which is one of the leading causes of chronic renal failure, uPAR was measured in urine and plasma of healthy human controls (N = 20), patients with culture-proven urosepsis (N = 30), and healthy human volunteers intravenously injected with endotoxin (N = 7). RESULTS: Patients had elevated uPAR levels in both plasma and urine. Three hours after endotoxin challenge in volunteers, there was also a significant increase of uPAR in plasma and in urine. The urine/plasma ratio for uPAR was highly elevated during urosepsis and experimental endotoxemia, suggesting local production in the kidney. Accordingly, damaged tubuli strongly expressed uPAR during pyelonephritis. Moreover, tubular epithelial cells produced uPAR in vitro, and this secretion was strongly up-regulated after stimulation with interleukin-1 beta or tumor necrosis factor-alpha. CONCLUSIONS: We found that uPAR is released systemically and in the urinary tract during urosepsis and experimental endotoxemia. This systemic and renal production of uPAR during pyelonephritis may play a central role in eliminating the infection and protecting renal function.     

Intermittent pneumatic calf compression for prevention of deep venous thrombosis in general abdominal surgery

A prospective randomized trial is described in 119 patients undergoing major abdominal general surgical procedures. Half of the patients were treated prophylactically with intermittent pneumatic calf compression, begun after the induction of anesthesia and continued until the patient was walking; the other half acted as controls. Deep venous thrombosis was detected by iodine-125 fibrinogen scanning and confirmed by venography, and did not differ significantly in the control and treated groups. One fatal pulmonary embolism occurred in each group. The presence of malignancy of the gastrointestinal tract did not influence the results. The findings suggest that pneumatic compression delayed the development of deep venous thrombosis postoperatively and that perhaps it should be continued until discharge from hospital.     

Bupivacaine 0.1% does not improve postoperative epidural fentanyl analgesia after abdominal or thoracic surgery

Epidural infusions of fentanyl, in a 10 micrograms.ml-1 concentration, combined with bupivacaine 0.1% were compared with epidural infusions of fentanyl alone for postoperative analgesia following abdominal or thoracic surgery. There were no detectable differences between the two groups in analgesia (mean visual analogue scale pain scores ranging between 15-35 mm), average infusion rates of 7-9 ml.hr-1, and serum fentanyl concentrations which reached 1-2 ng.ml-1. There was no difference in postoperative pulmonary function (pH, PaCO2, SaO2), or bowel function (time to flatus or po fluids). The incidence of side-effects including somnolence, nausea and vomiting, pruritus and postural hypotension was also similar. Of the patients receiving fentanyl and bupivacaine 0.1%, three developed a transient unilateral sensory loss to pinprick and ice, and two of these patients had unilateral leg weakness equal to a Bromage 1 score. The addition of bupivacaine 0.1% does not improve epidural infusions of fentanyl using a 10 micrograms.ml-1 concentration following abdominal or thoracic surgery.     

Cardioplegic arrest does not increase the risk of atrial fibrillation after coronary artery bypass surgery.

OBJECTIVE: Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass grafting (CABG). It is a considerable source of morbidity, prolongs hospital stay and increases costs of treatment. Atrial cannulation, cardiopulmonary bypass and cardioplegic arrest have been suggested to play a role in the development of AF after CABG. The aim of this case-control study was to evaluate the role of cardiopulmonary bypass and cardioplegic arrest in the development of postoperative AF. METHODS: Data from 114 patients undergoing CABG without cardiopulmonary bypass and cardioplegic arrest (off-pump) between October, 1998 and December, 2002 were evaluated for the occurrence of postoperative AF. Each patient was individually matched by gender, age (+/-3 years), left ventricle ejection fraction (+/-5%), history of myocardial infarction, unstable angina, and beta-blocker medication with patients undergoing CABG with cardiopulmonary bypass and cardioplegic arrest (on-pump) during the same period. The data from off-pump and on-pump groups were compared. RESULTS: Off-pump and on-pump groups had similar preoperative characteristics. The number of distal anastomoses was lower in the off-pump (2.3+/-0.9) than in the on-pump (3.9+/-1.1, (P<0.001) group. However, the incidence of postoperative AF in the off-pump (36.8%) and the on-pump groups (36.0%) did not differ from each other. Old age was the only independent predictor of AF after CABG. CONCLUSIONS: Neither cardiopulmonary bypass nor cardioplegic arrest increases the risk of postoperative AF after CABG.     

Early extubation does not increase complication rates after coronary artery bypass graft surgery with cardiopulmonary bypass

Background: With the evolution of anesthesia and surgical procedures, fast track extubation has gained an increased interest, mainly based on the possibility of reducing health costs seemingly without compromising patient care. Aim: To compare two groups of patients submitted to a non-fast track extubation and a fast track extubation protocol after coronary artery bypass graft surgery with cardiopulmonary bypass, regarding their times of ventilation and intubation and their complication rates in the postoperative period. Methods: During the year of 1998, 323 sequential patients scheduled for isolated coronary artery bypass graft surgery with cardiopulmonary bypass were enrolled in the study. Fifty-nine patients were excluded due to preoperative use of emergent mechanical and/or inotropic hemodynamic support, low body mass index (≤18–20 kg/m²), reoperations for acute surgical complications, off-pump coronary artery bypass graft surgery, severe respiratory disease, recent myocardial infarction (≤7 days) and absence of relevant data. Previous myocardial infarction (≥7 days), prophylactic intraaortic balloon pump and use of postoperative vasoactive drugs were not exclusion criteria. We compared 76 patients sequentially submitted to anesthesia by one of the authors with a fast track extubation protocol and 188 patients sequentially submitted to anesthesia by others in the same period and using a conventional anesthetic protocol. Results: Demographic data, previous medical and cardiac history, preoperative medication and operative data were all similar between the two groups. The mean ventilation and intubation times were significantly shorter in the fast track extubation group than in the non-fast track extubation patients (30 min vs. 7 h and 50 min vs. 8 h, respectively). Forty-two percent of patients in the fast track extubation group were extubated on arrival at the intensive care unit. Morbidity and mortality were similar in both groups. Conclusions: The study shows that a very fast track extubation protocol may be safely implemented in patients submitted to coronary artery bypass graft surgery with cardiopulmonary bypass.