Coagulation and fibrinolytic parameters in patients undergoing total hip replacement: influence of the anaesthesia technique

Morbidity and Mortality Following Total Hip and Knee Arthroplasty with Spinal versus General Anesthesia: A Retrospective Analysis

BACKGROUND

Despite the longstanding debate surrounding anesthesia in total joint arthroplasty, an optimal anesthetic mode has yet to be clearly identified. Patients undergoing total joint arthroplasty may be offered spinal anesthesia (SA) or general anesthesia (GA). While the arthroplasty literature has reported differences in postoperative morbidity, the hip fracture literature does not demonstrate the superiority of SA or GA. The purpose of this study was to further investigate this relationship and determine if there is a significant difference in morbidity and mortality between patients undergoing SA compared with those undergoing GA during primary total hip and knee arthroplasty surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients undergoing primary total hip or total knee arthroplasty from February 2007 to February 2021 were retrospectively reviewed. From this population, four cohorts were created: THA/GA (n = 1,266), THA/SA (n = 1,084), TKA/GA (n =882), and THA/SA (n = 2,067). Readmission within 90 days, mortality within 365 days, and thromboembolic events in the postoperative 30 days were compared using logistic regression analysis. The multivariate model controlled for age, body mass index (BMI), and Charlson Comorbidity Index (CCI).

RESULTS

The odds of experiencing a deep venous thrombosis (DVT) within 30 days postoperatively were elevated in the analysis of both the THA/GA (OR [odds ratio] = 3.1; 95% CI [confidence interval]: 1.5 to 7.0; P = 0.004) and the TKA/GA (OR = 1.9; 95% CI: 1.2 to 3.0; P = 0.005) groups. Similarly, the risk of pulmonary embolism (PE) as higher in the THA/GA cohort (OR = 3.9; 95% CI: 1.2 to 17.3; P = 0.04). There were also higher odds of mortality within 365 days postoperatively in THA/GA patients (OR = 4.3; 95% CI: 1.7 to 13.0; P = 0.004). No other differences existed among TKA patients.

CONCLUSION

Based upon these data, both spinal and general anesthesia are reasonable options for primary total knee arthroplasty with similar risk profiles. However, general anesthesia may be associated with higher rates of DVT in total joint arthroplasty and PE in total hip arthroplasty. General anesthesia was also loosely associated with increased mortality within one year of total hip arthroplasty, but this result should be considered with caution.

Lidocaine effects on coagulation assessed by whole blood rotational thromboelastometry

Lidocaine may be beneficial when added in solutions for the preservation of vascular grafts or solid organs as it has anti-inflammatory, endothelial protective, and antithrombotic effects. However, the mechanisms of lidocaine-induced changes in hemostasis were not elucidated until now. The aim of the study was to examine the effect of increasing concentrations of lidocaine on coagulation parameters and blood-clotting kinetics using velocity curves of clot formation assessed by rotational thromboelastometry. Ex-vivo blood coagulation using whole blood from healthy volunteers was studied with rotational thromboelastometry. For each volunteer, four assays were performed: saline control and samples with lidocaine end blood concentrations of 0.3, 0.6, and 0.9%. In this in-vitro study, whole blood from 15 healthy volunteers was used. Lidocaine concentration of 0.3% prolonged the initiation phase of clotting without significant differences in the propagation phase or clot stability and inhibited clot lysis compared with the control group. Higher lidocaine concentrations (0.6 and 0.9%) resulted in prolongation of both initiation and propagation phases and decreased clot firmness compared with the control group. Lysis was significantly increased only in the 0.6% lidocaine group compared with control. Although lidocaine concentration of 0.3% only delays coagulation initiation, the 0.6% concentration inhibits all phases of hemostasis and increases clot lysis compared with control. Higher lidocaine concentration results in very weak clot formation with very low lysis visible on thromboelastometry. More research is needed to explain the effects of lidocaine on clotting kinetics.

Outcomes of carotid endarterectomy under general and regional anesthesia from the American College of Surgeons' National Surgical Quality Improvement Program

OBJECTIVE

Despite multiple studies over more than 3 decades, there still is no consensus about the influence of anesthesia type on postoperative outcomes following carotid endarterectomy (CEA). The objective of this study was to investigate whether anesthesia type, either general anesthesia (GA) or regional anesthesia (RA), independently contributes to the risk of postoperative cardiovascular complications or death using the American College of Surgeons' National Surgical Quality Improvement Program (ACS NSQIP) database.

METHODS

Retrospective analysis of elective cases of CEA from 2005 through 2009 was performed. A propensity score model using 45 covariates, including demographic factors, comorbidities, stroke history, measures of general health, and laboratory values, was used to adjust for bias and to determine the independent influence of anesthesia type on postoperative stroke, myocardial infarction (MI), and death.

RESULTS

Of 26,070 cases listed in the ACS NSQIP database, GA and RA were used in 22,054 (84.6%) and 4016 (15.4%) cases, respectively. Postoperative stroke, MI, and death occurred in 360 (1.63%), 133 (0.6%), and 154 (0.70%) patients of the GA group, respectively, and in 58 (1.44%), 11 (0.27%), and 27 (0.67%) patients of the RA group, respectively. Stratification by propensity score quintile and adjustment for covariates demonstrated GA to be a significant risk factor for postoperative MI with an adjusted odds ratio (OR) and confidence interval (CI) of 2.18 (95% CI, 1.17-4.04), P = .01 in the entire study population. The OR for MI was 5.41 (95% CI, 1.32-22.16; P = .019) in the subgroup of patients with preoperative neurologic symptoms, and 1.44 (95% CI, 0.71-2.90; P = .31) in the subgroup of patients without preoperative neurologic symptoms.

CONCLUSIONS

This analysis of a large, prospectively collected and validated multicenter database indicates that GA for CEA is an independent risk factor for postoperative MI, particularly in patients with preoperative neurologic symptoms.

[Comparison of hemostatic markers under different techniques for anesthesia-analgesia in total hip or knee replacement]

BACKGROUND AND OBJECTIVE

Surgery promotes a state of hypercoagulability, predisposing to the possibility of postoperative thromboembolic complications. Our aim was to determine whether certain combinations of techniques (neuraxial, intravenous or both) for anesthesia and analgesia might be associated with attenuation of the prethrombotic state following total hip or knee replacement.

METHODS

Prospective longitudinal study of 45 patients undergoing elective hip or knee prosthetic surgery. The patients were randomized to 3 groups to receive different anesthesia-analgesia combinations: spinal-intravenous, spinal-epidural, or general-intravenous. From induction until 36 hours after surgery, we recorded the postoperative time course of the following markers of coagulation and fibrinolysis: platelet count; fibrinogen level; activated partial thromboplastin time; international normalized ratio; and levels of prothrombin activation fragments 1 and 2, thrombin-antithrombin III complex, and D-dimer.

RESULTS

No statistically significant between-group differences were found in patient demographic, clinical, surgical or postoperative data. No symptomatic thromboembolic complications or deaths were recorded in the 30 days after surgery. Statistically significant differences were found in laboratory results for samples taken 36 hours after surgery. Patients who received spinal-epidural anesthesia and analgesia had lower levels of prothrombin activation fragments 1 and 2 and longer activated partial thromboplastin times than the group receiving the spinal-intravenous combination.

CONCLUSIONS

The anesthetic technique used during surgery did not affect hemostasis. However, continuous epidural analgesia in the postoperative recovery period attenuated some markers of hypercoagulability.

Local Anesthetics Inhibit Tissue Factor Expression in Activated Monocytes via Inhibition of Tissue Factor mRNA Synthesis

Local anesthetics have been reported to have anticoagulant properties, but the mechanisms responsible for this action are poorly understood. Here, we evaluated the in vitro effects of 3 local anesthetics—lidocaine, ropivacaine, and bupivacaine—on the tissue factor expression by monocytes. Monocytes from peripheral blood were stimulated with lipopolysaccharide (LPS) in the presence or absence of local anesthetics. All 3 local anesthetics inhibited the expression of tissue factor antigen and tissue factor activity in LPS-stimulated monocytes in a dose- and time-dependent manner and reduced tissue factor messenger RNA (mRNA) expression in endothelial cells and a monocytic cell line. None of the 3 drugs induced apoptosis or affected the viability of monocytes. Our findings that local anesthetics inhibited the tissue factor induction in activated monocytes by inhibiting tissue factor mRNA level may demonstrate the feasibility of using local anesthetics in hypercoagulable and inflammatory conditions.

Predictors of mortality following symptomatic pulmonary embolism in patients undergoing noncardiac surgery

PURPOSE

To determine 30-day mortality and predictors of mortality following perioperative pulmonary embolism (PE).

METHODS

We searched both the Mayo Clinic electronic medical records and Autopsy Registry, between January 1, 1998 and December 31, 2001, for patients who developed PE within 30 days after noncardiac surgery performed under general or neuraxial anesthesia. Medical records of all identified patients were reviewed using standardized data collection forms. The association between risk factors for PE and 30-day post-PE mortality was assessed using t tests, exact binomial tests, and logistic regression.

RESULTS

We identified 158 patients with probable or definite perioperative PE. The overall 30-day mortality from the day of PE was 25.3%, i.e., 40 patients died. Hypotension requiring treatment, need for mechanical ventilation, and intensive care unit admission were the prominent univariate predictors of 30-day mortality (all P <or= 0.001). Other significant factors were exact bi normal tests, and higher ASA physical status (P = 0.002), longer surgical time (P = 0.030), recent central vein cannulation (P = 0.021) and intraoperative use of either blood transfusions or other blood products (P = 0.010). Using multivariable analysis, hemodynamic instability was found to be the dominant independent risk factor associated with mortality.

CONCLUSIONS

Perioperative PE is associated with a high 30-day mortality. Patients who experience hemodynamic instability and require vasoactive treatment at presentation of PE have extremely low survival rates; therefore, for these patients the most aggressive therapeutic modalities should be considered.

Long-haul air travel before major surgery: a prescription for thromboembolism?

OBJECTIVE

To investigate the Incidence of postoperative venous thromboembolism (VTE) in patients who had flown long distances before major surgery.

PATIENTS AND METHODS

Using the Mayo Clinic computerized patient database, we Identified patients who had flown more than 5000 km before major surgery (travelers) and had experienced an episode of clinically significant VTE within 28 days after surgery. Individual medical records were reviewed for the diagnosis of VTE, pertinent risk factors, and outcome. We compared the Incidence of VTE in travelers to the incidence of VTE in patients from North America (nontravelers) undergoing similar surgical procedures.

RESULTS

Eleven patients met our criteria for long-haul air travel and clinically significant VTE within 28 days after surgery. Compared with nontravelers undergoing similar surgical procedures, long-haul travelers had a higher Incidence of VTE (4.9% vs 0.15%; P < .001). Compared with nontravelers who developed VTE, travelers were younger (P = .006), developed VTE earlier in the postoperative course (P = .01), had higher American Society of Anesthesiologists physical status classification (P = .02), and had higher prevalence of smoking (P = .007). Of the 11 travelers with VTE, 10 were of Middle Eastern origin.

CONCLUSION

Prolonged air travel before major surgery significantly increases the risk of perioperative VTE. Such patients should receive more Intensive VTE prophylactic measures during the flight and throughout the perioperative period.

Thromboembolic disease prophylaxis in patients with hip fracture: a multimodal approach

OBJECTIVES

To assess if pneumatic compression in conjunction with chemoprophylaxis is an effective way to reduce the incidence of deep vein thrombosis in orthopedic trauma patients sustaining fragility hip fractures.

DESIGN

Two hundred patients admitted to the authors' institution between May 1998 and June 2002 for fractures of the hip were prospectively studied. All patients were treated operatively and received the VenaFlow calf compression device on both lower extremities immediately following surgery. Chemical prophylaxis of either aspirin (n = 67) or warfarin (n = 133) was administered in addition to mechanical compression. A noninvasive serial color flow duplex scan was performed 1 to 11 days postoperatively (mean 4.5 days) to determine the presence or absence of deep vein thrombosis. All patients were followed clinically 3 months postoperatively for a clinical evaluation of symptomatic deep vein thrombosis or pulmonary embolism.

RESULTS

Overall, the incidence of deep vein thrombosis was 3.5% (7 of 200) and included only 1 proximal thrombosis (1 out of 200, or 0.5%) and no pulmonary embolism. Five of the 7 patients positive for deep vein thrombosis were in the mechanical compression and warfarin prophylaxis group and 2 were in the aspirin arm of the study. For patients with deep vein thrombosis, the average number of risk factors was 3.71, whereas patients without clots averaged 1.75 clinical risk factors (P < or = 0.05). Three patients in the warfarin group developed bleeding complications (1 with a gastrointestinal bleed and 2 with minor bleeding not at the operative site). No evidence of a symptomatic deep vein thrombosis or pulmonary embolism was reported within a 3-month period following hospitalization.

CONCLUSIONS

Our findings suggest mechanical compression with the VenaFlow calf compression device in conjunction with chemoprophylaxis is an effective means of reducing thromboembolic disease in this high-risk population.

Complications of major aortic and lower extremity vascular surgery

Atheromatous disease and invasive intervention of the aortoiliac and distal arteries are common. Morbidity and mortality have been reduced through understanding and management of patient risk factors. Complications of this form of treatment affect all organ systems; mortality is most frequently caused by a cardiovascular complication (eg, myocardial infarction). Infection, leading to aortoenteric fistula is a dreaded complication, and paraplegia, though rare, is a devastating outcome. Multiorgan failure and death may result from a systemic inflammatory response syndrome. Vascular surgery for infrainguinal disease also has a significant cardiovascular complication rate. Resulting complications may affect all organs; loss of an extremity may occur. The first part of this article reviews perioperative and postoperative complications of open aortic repair and lower-extremity revascularization and addresses the issue of regional anesthesia for major vascular surgery. The second part reviews endovascular aortic repair (EVAR). EVAR is a new intervention that combines surgery and radiology. Complications of EVAR are similar to open repair, but early results suggest they may be less frequent. New technology leads to new complications; endoleaks, migration of the endoprosthesis, and surgical conversion are unique to EVAR. The benefits of EVAR may be less blood loss, shorter hospitalization, and less cardiovascular stress; the risks may be aneurysm recurrence, prolonged surveillance and repeated secondary procedures. The development of EVAR, the complications, and the anesthesia-related concerns of EVAR, including its use in management of acute abdominal aortic aneurysm are reviewed.

Adjusted transfusion triggers improve transfusion practice in orthopaedic surgery

Although blood transfusion has never been safer, there remains concern about adverse effects. We designed guidelines, the 6-8-10-Flexinorm, based on the conditions which are relevant to the decision to transfuse. To evaluate these new guidelines, we performed a case-control study in patients undergoing elective primary total hip replacement. The study consisted of two parts. In the first part, physicians were strongly encouraged to use the new guidelines; in the second part, only registration took place. During the first and second part of the study, the use of packed red cells (PRC) in Hospital A (study hospital) decreased from 1.1 +/- 1.5 to 0.6 +/- 1.2 and 0.3 +/- 0.9 units, whereas in Hospital B (control), the use of PRC remained unchanged (1 +/- 1.5, 1 +/- 1.7 and 1 +/- 2 units). In the prestudy groups, 43% of the patients in Hospital A were transfused compared to 45% in Hospital B. In the first and second part of the study, 27%, respectively, 14% of the patients in Hospital A were transfused compared to 40% in both periods in Hospital B. The new guidelines lead to a reduction in the use of allogeneic blood and a decrease in the number of patients transfused.

["Alternative" effects of local anesthetic agents]

The following article summarizes different aspects of local anesthetic effects that cannot be explained purely by a sodium channel blockade. Particularly remarkable is hereby their antiinflammatory activity, e.g. the inhibition of pathological changes such as excessive stimulation of the inflammatory system, without compromising the host defense system. In contrast to other immunosuppressive drugs commonly used for treating such conditions, local anesthetics look promising for the future as a new therapeutic option. Besides general anesthetic activity, local anesthetics exert cerebroprotective effects and are furthermore, in consideration of their cardiovascular stability, of interest during neuroanesthetic procedures. In addition, local anesthetics are known for their potency to minimize bronchial hyperreactivity, although details of the underlying mechanisms are not yet elucidated. These effects of local anesthetics may represent interesting prospects for which their relevance has to be determined.

Comparison of general and spinal anesthesia and their influence on hemostatic markers in patients undergoing total hip arthroplasty

STUDY OBJECTIVE

To evaluate the profile of molecular hemostatic markers in patients receiving either spinal or balanced general anesthesia for total hip arthroplasty.

DESIGN

Open, randomized, observational study.

SETTING

Orthopedic unit and central laboratory of a university hospital.

PATIENTS

26 consenting ASA physical status II and III inpatients undergoing total hip arthroplasty with general balanced anesthesia (n = 10) or spinal (regional) anesthesia (n = 16).

INTERVENTIONS

The time course of seven procoagulatory and fibrinolytic parameters was examined during and after surgery in both groups of patients (general and regional). Blood samples were drawn on the day before surgery, directly before induction of general anesthesia or regional anesthesia, respectively, intraoperatively (before bone manipulation), at the end of surgery, and on the mornings of postoperative days 1 and 5.

MEASUREMENTS AND MAIN RESULTS

The coagulation samples were centrifuged within 1 hour of collection at 2,300 g for 15 minutes at 4 degrees C. Hemoglobin, hematocrit, platelets, fibrinogen, prothrombin time, thrombin time, activated partial thromboplastin time, antithrombin, and protein C were measured immediately on arrival at the laboratory. Specimens were then aliquoted and stored at -70 degrees C. Within 2 weeks, samples were thawed and prepared for the following assays: thrombin-antithrombin complexes (TAT complexes), D-dimers, plasminogen activator inhibitor type 1 (PAI-1), and plasminogen and plasmin inhibitor. Maximum activation of coagulation was not reached until 2 hours postoperatively and then slowly decreased until normal values were reached around the fifth postoperative day. Parameters displaying the greatest changes were antithrombin and D-dimers. No statistically significant differences were found between the two groups at the individual time points.

CONCLUSION

Our initial hypothesis that the lesser risk of postoperative DVT in patients undergoing total hip arthroplasty in regional anesthesia is reflected in the course of the plasmatic molecular markers of hemostasis could not be verified. There were no significant differences in the timely course of the markers at any given time point.

General anesthesia versus regional anesthesia

No distinct advantage is apparent between regional and general anesthesia when considering perioperative cardiac morbidity and mortality in peripheral vascular surgery. However, there is some evidence to support regional anesthesia over general anesthesia in an effort to optimize graft patency if the regional technique is extended into the postoperative period to provide neuraxial analgesia. An inadequate number of randomized, controlled trials have been conducted to determine whether regional or general anesthesia should be performed for carotid endarterectomy. The nonrandomized trials do support regional anesthesia by virtue of reductions in stroke, myocardial infarction, and death. A randomized, prospective trial is needed to verify these outcomes. The choice of technique does not appear to affect mortality in patients requiring hip fracture surgery, although Urwin et al. (29) reported less 1-month mortality in patients receiving regional anesthesia. General anesthesia has been associated with increased blood loss and thromboembolic complications in patients undergoing hip fracture repair. Epidural anesthesia has been shown to promote quicker return of bowel function postoperatively when the catheter has been sited at T12 or higher. Anastomotic breakdown in patients with epidural anesthesia/analgesia has rarely been reported. Most studies tend to show quicker return of bowel function when local anesthetics alone are administered epidurally.

Regional Block Anaesthesia - How Effective is it for Extremity Trauma?

Regional block anaesthesia (RBA) techniques are eclipsed by the widespread use of general anaesthesia (GA), especially in trauma surgery. This is despite the numerous advantages that regional blocks have to offer. We conducted a study to evaluate efficacy, safety and feasibility of RBA in isolated extremity trauma in war scenario. A prospective study was carried out over a period of eight months. There were a total of 96 patients with splinter, mine blast and gun shot wounds. Supraclavicular or axillary brachial block was employed for upper extremity surgery. 3 in 1 femoral block with classical sciatic block at hip or popliteal fossa was administered for lower limb operations. All patients were stabilized prior to the procedure. A combination of lignocaine 3 mg/kg of 2% and bupivacaine 1.5 mg/kg of 0-5% with dilution to make a volume of 0.75 ml/kg was employed. Assessment was made for onset, duration and degree of anaesthesia. Haemodynamic parameters and oxygen saturation were measured during the peritraumatic period. 92.5% cases had good motor and sensory anaesthesia and permitted unhindered surgery without supplementation. The rest required GA/dissociative anaesthesia (DA). Post operative pain relief lasted for an average of 4-5 hours. No patient had derangement of haemodynamic parameters or oxygen saturation. There was no systemic drug toxicity, local complications or mortality in our series. We found RBA for isolated extremity trauma to be simple, safe and effective with consistent results.

Pharmacokinetics of coagulation factors: clinical relevance for patients with haemophilia

Haemophilia is a recessively inherited coagulation disorder, in which an X-chromosome mutation causes a deficiency of either coagulation factor VIII (FVIII) in haemophilia A, or factor IX (FIX) in haemophilia B. Intravenous administration of FVIII or FIX can be used to control a bleeding episode, to provide haemostasis during surgery or for long term prophylaxis of bleeding. In special cases, activated factor VII (FVIIa) may be used instead of FVIII or FIX. The aim of this work is to review the pharmacokinetics of FVIII, FIX and FVIIa and to give an outline of the use of pharmacokinetics to optimise the treatment of patients with haemophilia. The pharmacokinetics of FVIII are well characterised. The systemic clearance (CL) of FVIII is largely determined by the plasma level of von Willebrand factor (vWF), which protects FVIII from degradation. Typical average CL in patients with normal vWF levels is 3 ml/h/kg, with an apparent volume of distribution at steady state (Vss) that slightly exceeds the plasma volume of the patient, and the average elimination half-life (t1/2) is around 14 hours. There are still some discrepancies in the literature on the pharmacokinetics of FIX. The average CL of plasma-derived FIX seems to be 4 ml/h/kg, the Vss is 3 to 4 times the plasma volume and the elimination t1/2 often exceeds 30 hours. FVIIa has a much higher CL (average of 33 ml/h/kg), and a short terminal t1/2 (at 2 to 3 hours). The Vss is 2 to 3 times the plasma volume. Since the therapeutic levels of coagulation factors are well defined in most clinical situations, applied pharmacokinetics is an excellent tool to optimise therapy. Individual tailoring of administration in prophylaxis has been shown to considerably increase the cost effectiveness of the treatment. Dosage regimens for the treatment of bleeding episodes or for haemostasis during surgery are also designed using pharmacokinetic data, and the advantages of using a constant infusion instead of repeated bolus doses have been explored. The influence of antibodies (inhibitors) on the pharmacokinetics of FVIII and FIX is in part understood, and the doses of coagulation factor needed to treat a patient can tentatively be calculated from the antibody titre. In conclusion, therapeutic monitoring of coagulation factor levels and the use of clinical pharmacokinetics to aid therapy are well established in the treatment of patients with haemophilia.

Current trends in perioperative pain management

Wider use of optimized multimodal accelerated postoperative recovery programs require that anesthesiologists step out of traditional operating room anesthesia roles and even beyond current pain management consultant roles. Development of optimal postoperative recovery services requires close collaboration between anesthesiologists, surgeons, nurses, physical therapists, administrators, and others involved in the management of patients after surgery. Optimization of perioperative care is an ongoing process enhanced by clinical investigation; however, making significant improvements to clinical practice does not have to wait for additional research data, but should proceed now, with broader application of techniques known to enhance rehabilitation and recovery. Based on existing data, the challenges of developing perioperative recovery services seem likely to be rewarded with improved patient outcomes and reduced cost.

Effect of tourniquet use on activation of coagulation in total knee replacement

Total knee replacement often is performed with tourniquet application. The advantages of a dry field, including fixation, are well known, but it still is debatable if tourniquet application increases deep vein thrombosis. Measurement of coagulation markers is a well accepted method of studying thrombogenesis activation intraoperatively and postoperatively. Twenty patients undergoing total knee replacement with subarachnoid anesthesia were assigned randomly to two groups: either with tourniquet application (Group I) or without tourniquet application (Group II). There were no differences between patients in the two groups in terms of age, gender, diagnosis (all had osteoarthritis), operative time, and total (intraoperative and postoperative) blood loss. Markers for thrombin generation and fibrinolysis were measured. Blood samples were drawn at four times: baseline before the operation; after bone cuts; after cement fixation (Group II) or 2 minutes after tourniquet deflation (Group I); and 1 hour after surgery. Markers of thrombin generation and fibrinolysis showed a significant increase from baseline in all the patients. In Group II these markers started to increase during surgery, whereas in Group I the increase occurred at the end of the procedure when the tourniquet was deflated. The total amount of thrombin generation was significantly higher in Group II (without tourniquet), whereas fibrinolysis was significantly greater in Group I. Total knee replacement is accompanied by a hypercoagulative state with or without the use of a tourniquet, but it seems to be higher when the tourniquet is not used. In addition, tourniquet application may increase fibrinolysis.

The incidence of venous thromboembolism after total hip arthroplasty: a specific hypotensive epidural anesthesia protocol

We retrospectively reviewed all consecutive unilateral primary total hip arthroplasty (THA) procedures performed by 3 attending surgeons on the Arthroplasty Service at our institution from January 1, 1990, to December 31, 1993. All surgery was performed under a specific hypotensive epidural anesthesia protocol. Hypotensive epidural anesthesia at our institution provides a lower level of hypotension (mean arterial pressure of 50-60 mmHg) as compared to hypotensive anesthesia used more generally around the world (mean arterial pressure >70 mmHg). For each patient, hospital and postdischarge office records for a minimum of 3 months after surgery were reviewed for the type of postoperative screening test, the incidence of deep venous thrombosis (DVT), and the incidence of symptomatic pulmonary embolism (PE). Overall, 2,592 primary unilateral THAs were performed with 78.6% (2,037 of 2,592) of patients receiving a venogram. Our protocol for thromboembolic disease prophylaxis in these patients included aspirin postoperatively as well as antithromboembolic disease stockings and early ambulation (24-48 hours postoperatively). The 555 patients who did not receive venography were managed with a different protocol that included warfarin postoperatively as well as antithromboembolic disease stockings and early ambulation. This high-risk group consisted of patients who received warfarin preoperatively (ie, cardiac valve) or patients with a history of DVT who were to receive warfarin postoperatively, regardless of venography result. Overall, DVT was diagnosed in 10.3% (210 of 2,037) of patients who had a venogram. Of these patients who had venography, 2.3% (46 of 2,037) had an isolated proximal DVT; 6.0% (123 of 2,037), a distal DVT; and 2.0% (41 of 2,037), both a proximal and a distal DVT. Of the 87 cases of proximal DVT identified, 60.9% (53 of 87) were femoral DVT; 18.4% (16 of 87), popliteal DVT; and 20.7% (18 of 87), both femoral and popliteal DVT. Of the 164 distal DVT, 68.3% (112 of 164) were major calf DVT and 31.7% (52 of 164) were minor calf DVT. The overall incidence of major venous thrombosis (sum of proximal and major calf thrombi) was 9.8% (199 of 2,037) in patients who had venography. Ventilation-perfusion scanning was used selectively in patients symptomatic for PE. Overall, symptomatic PE was diagnosed by ventilation-perfusion scan in 1.0% (26 of 2,592) of patients, with 0.58% (15 of 2,592) of patients having an in-hospital PE. Of the 15 patients who had an in-hospital PE, 11 patients had a venogram, and only 3 of 11 were positive. Late symptomatic PE was defined from discharge (mean, 7 +/- 2 days) to 3 months after discharge from the hospital and occurred in 0.42% (11 of 2,592) of patients. One of the 11 late symptomatic PEs was fatal. In the overall study, this represents 0.04% (1 of 2,592) fatal PE. Of the 11 patients with a late symptomatic PE, 10 had venograms in the hospital, and all 10 were negative for DVT. Overall, in the patients with a positive venogram, the incidence of symptomatic PE was 1.4% (3 of 210), whereas in the patients with a negative venogram, the incidence of symptomatic PE was 0.44% (8 of 1,827). At our institution, patients who undergo primary THA performed with hypotensive epidural anesthesia, postoperative aspirin, antithromboembolic disease stockings, and early ambulation have a low risk for thromboembolic disease.

[Benefit-risk and monitoring modalities of different techniques and methods of postoperative analgesia]

This review aimed to determine the benefits-risks ratio of postoperative analgesia. The various agents usually used for intravenous postoperative analgesia (paracetamol, NSAID's, opioids), and the techniques for postoperative analgesia (PCA, epidural, perinervous block) are analysed. The rules proposed for the monitoring of postoperative analgesia are considered.

[Postoperative locoregional analgesia in the adult: epidural and peripheral techniques. Indications, adverse effects and monitoring]

Regional analgesia is a very effective way to treat postoperative pain. Lumbar and thoracic epidural analgesia are well adapted to major abdominal and thoracic surgery. Nevertheless, respiratory side effects induced by opioids are potentially severe and an adequate monitoring is essential. In orthopaedic surgery, perineural blocks are the best technique to manage postoperative pain and perineural catheters may be used. The importance of intra-articular analgesia, simple and safe, is not fully understood. The association of a local anaesthetic inducing a minor motor block and a strong sensitive block (bupivacaine, ropivacaine), with an opioid seems to be the best pharmacologic choice regarding quality of analgesia and safety. Benefits of postoperative regional analgesia on mortality and morbidity are not demonstrated. Medical and nursing staff and specialized units should improve quality of postoperative regional analgesia as well. General guidelines for the practice of regional anaesthesia must be closely followed.

Comparison of general and epidural anesthesia in patients undergoing primary unilateral THR

One hundred ninety-five consecutive patients underwent 195 primary unilateral total hip arthroplasties between January 1988 and December 1993. Patients were divided into three groups based on the type of anesthesia utilized for their procedure. Group I consisted of 108 patients (59 women and 49 men; average age 56 years) who had general endotracheal anesthesia alone. Group II consisted of 70 patients (41 women and 29 men, average age 58 years) who had general endotracheal anesthesia with epidural augmentation intraoperatively and postoperatively. Group III consisted of 17 patients (6 women and 11 men, average age 62 years) who had epidural anesthesia only. Data were analyzed by anesthesia group to compare a variety of clinically relevant factors. No statistically significant differences among groups were noted regarding average age at surgery, the underlying diagnoses leading to joint replacement, the number of preexisting medical conditions, length of hospitalization, nonsurgical operating room time, intraoperative blood transfusions, intraoperative femur fractures, deep venous thrombosis, deep infections, death, or the prevalence of postoperative urinary tract infections. Postoperative urinary tract infections correlated with duration of Foley catheterization, but not the duration of epidural catheterization. Significant differences among anesthesia groups were observed for two factors: 1) estimated intraoperative blood loss was highest for Group I (P < .05) and was primarily a function of surgical time (P < .0001), and 2) postoperative Hemovac output (over the first and second postoperative 24-hour periods) was greatest for Group II (P < .05). Epidural anesthesia appears to be a safe modality in patients undergoing primary unilateral total hip replacement.

Hypotensive epidural anesthesia for total hip arthroplasty: a review

Hypotensive epidural anesthesia provides arterial hypotension to maintain a mean arterial pressure of 50 mmHg and it can be used to reduce blood loss during total hip replacement. The technique combines an extensive epidural blockade with an intravenous infusion of low-dose epinephrine. This results in arterial hypotension, but with preservation of central venous pressure, heart rate, stroke volume, cardiac output, and an augmentation of blood flow to the lower extremity. The technique does not appear to adversely affect cardiac, renal, or cerebral function and is used safely in patients with hypertension, ischemic heart disease, and in the elderly. Intraoperative blood losses during primary total hip replacement are between 100 and 300 mL. Perioperative transfusions have declined with the introduction of the technique. Radiological evidence of improved fixation of cemented acetabular components has been observed. Rates of deep-vein thrombosis are low: 2-3% proximal deep-vein thrombosis with an overall rate of 10%. In-hospital mortality is 0.1%; lower than previously published rates. In conclusion, hypotensive epidural anesthesia is safe and provides a number of advantages over conventional anesthetic techniques for total hip replacement.

Coagulopathies in patients after transurethral resection of the prostate: spinal versus general anesthesia

This prospective, randomized study evaluated the effects of spinal versus general anesthetic technique on perioperative blood loss and the development of postoperative coagulopathies in 50 patients undergoing transurethral resection of the prostate (TURP). Preoperative hematologic measurements included hemoglobin, platelet count, electrolytes, prothrombin time, partial thromboplastin time, fibrinogen, factor V, plasminogen, antithrombin III, and fibrinogen degradation product (FDP) levels. All hematologic blood samples wre repeated postoperatively at 1, 6, and 24 h. Intraoperative blood loss was not significantly different between the spinal and general anesthesia groups. The total blood loss after TURP was significantly correlated (r = 0.76; P < 0.0001) with the prostatic tissue weight. When the tissue weight resected exceeded 35 g, blood loss was in excess of the linear correlation shown with the weight of resected prostatic tissue. Platelet count decreased and prothrombin time increased in the spinal group at all postoperative time intervals compared to preoperative value (P < 0.05). There was no significant difference in measured coagulation variables (fibrinogen, factor V, plasminogen, antithrombin III, and FDP) between the spinal and general anesthesia groups, but there were significant decreases in postoperative fibrinogen and Factor V levels compared to preoperative values in both spinal and general anesthesia groups. Three patients (6%) had increased FDP levels 1 h postoperatively. The prostatic tissue weight and the surgical duration was significantly higher in these patients. We conclude that perioperative blood loss in TURP patients is not affected by the anesthetic technique. However, 6% of TURP patients developed subclinical intravascular coagulopathies which correlated with mass of resected prostate tissue.

Effect of dihydroergotamine on leg blood flow during combined epidural and general anaesthesia and postoperative deep vein thrombosis after cholecystectomy

The effects of dihydroergotamine (DHE) on the circulation of the leg during combined epidural and general anaesthesia were studied to determine if DHE would enhance leg blood flow and prevent postoperative deep vein thrombosis in a double-blind trial of 40 elderly female patients subjected to cholecystectomy. Central and big toe temperature, arterial blood pressure, heart rate, calf volume and arterial inflow of the leg by electrical impedance plethysmography and the venous outflow by Doppler method were measured. DHE 0.5 mg subcutaneously reduced the volume of the leg, i.e. increased the electrical impedance, probably due to venous vasoconstriction. Simultaneously the need for etilefrine hydrochloride was reduced. No significant changes in the pulsatile inflow of the leg or the outflow were detected. Deep vein thrombosis (DVT) was detected by fibrinogen uptake test in five patients (three in DHEH and two in the control group) and verified by ascending phlebography in four patients. Intraoperative characteristics in patients with postoperative DVT were tachycardia (P < 0.001), enhanced need for etilefrine (P < 0.01) and a more rapid increase in big toe temperature (P < 0.05) after induction of epidural analgesia, compared with patients without DVT. Femoral vein flow velocity remained at the preinduction level, whereas pulsatile arterial inflow slightly increased. Together with a low basal impendance of the leg, the changes were indicative of a more intense vasodilatation, probably leading to stagnant flow and development of postoperative deep vein thrombosis.