The hemodynamic and fibrinolytic response to low dose epinephrine and phenylephrine infusions during total hip replacement under epidural anesthesia.

Lower rates of deep vein thrombosis have been noted following total hip replacement under epidural anesthesia in patients receiving exogenous epinephrine throughout surgery. To determine whether this is due to enhanced fibrinolysis or to circulatory effects of epinephrine, 30 patients scheduled for primary total hip replacement under epidural anesthesia were randomly assigned to receive intravenous infusions of either low dose epinephrine or phenylephrine intraoperatively. All patients received lumbar epidural anesthesia with induced hypotension and were monitored with radial artery and pulmonary artery catheters. Patients receiving low dose epinephrine infusion had maintenance of heart rate and cardiac index whereas both heart rate and cardiac index declined significantly throughout surgery in patients receiving phenylephrine (p = 0.0001 and p = 0.0001, respectively). Tissue plasminogen activator (t-PA) activity increased significantly during surgery (p < 0.005) and declined below baseline postoperatively (p < 0.005) in both groups. Low dose epinephrine was not associated with any additional augmentation of fibrinolytic activity perioperatively. There were no significant differences in changes in D-Dimer, t-PA antigen, alpha 2-plasmin inhibitor-plasmin complexes or thrombin-antithrombin III complexes perioperatively between groups receiving low dose epinephrine or phenylephrine. The reduction in deep vein thrombosis rate with low dose epinephrine is more likely mediated by a circulatory mechanism than by augmentation of fibrinolysis.

Post-operative delirium: predictors and prognosis in elderly orthopedic patients.

OBJECTIVE: To compare the effect of post-operative analgesia using epidural versus intravenous infusions on the incidence of delirium after bilateral knee replacement surgery in elderly patients. Additional risk factors and impact on post-operative recovery were also assessed. DESIGN: Prospective randomized controlled trial. SETTING: Urban referral hospital specializing in elective orthopedic surgery. PATIENTS: 60 consecutive patients undergoing bilateral knee replacement surgery with epidural anesthesia were approached; 51 patients were eligible and consented. The mean age was 68, 55% were women, and there was a high prevalence of comorbid medical disease. No patient was demented pre-operatively. INTERVENTION: Random allocation to either continuous epidural infusion of bupivacaine and fentanyl or continuous intravenous infusion of fentanyl. Infusions were initiated at the first complaint of pain and continued through the 36- to 48-hour stay in the recovery room. MAIN OUTCOME MEASURE: Acute post-operative delirium defined using an algorithm based on DSM III criteria. RESULTS: The overall incidence of acute delirium was 41%, with no difference between types of post-operative analgesia. Predictors of delirium were age, gender, and pre-operative alcohol use. All cases resolved within 1 week, and length of stay and achievement of physical therapy goals were the same for delirious and non-delirious patients. CONCLUSIONS: There is a high incidence of post-operative delirium in elderly non-demented patients following bilateral knee replacement, regardless of whether post-operative analgesia is administered by the epidural or intravenous route.

Perioperative medical considerations in patients with rheumatoid arthritis.

Patients who suffer from chronic rheumatologic diseases, such as rheumatoid arthritis, frequently require orthopedic surgical intervention during the course of their illness. This article provides the reader with an overview of approaches to postoperative risk stratification. Reviewed are the basic concepts that underlie perioperative medical management, including such issues as the preoperative medical assessment, the currently employed anesthetic techniques, and approaches to postoperative analgesia. The impact of comorbid conditions on surgical outcome is discussed as are specific clinical problems that have particular relevance to the patient with rheumatoid arthritis.

Anesthesia on the rheumatoid patient.

In the orthopedic setting, the anesthesiologist often encounters the rheumatoid patient after the disease has run a resistant course. Despite optimal medical therapy, the patient at this point has intolerable levels of pain or limitation of function because of structural joint damage. Given the duration of the disease and severity of symptoms, a number of pharmacologic modalities already have been tried for which the patient has suffered some side effects. Now that the disease has spanned a significant period, the patient has become older with one or more coexisting illnesses. These comorbidities may occur independently or as part of the extra-articular manifestations of the underlying rheumatic disorder. Because of these reasons, rheumatoid patients today present major anesthetic challenges.

Effects of epidural anesthesia on the incidence of deep-vein thrombosis after total knee arthroplasty.

Epidural anesthesia has been reported to reduce the prevalence of deep-vein thrombosis after total hip arthroplasty compared with the prevalence after general anesthesia. However, the effect of epidural anesthesia on the rate of thrombosis after total knee arthroplasty has not been reported previously, to our knowledge. A review was conducted of 705 total knee arthroplasties (541 patients) that had been performed by a single surgeon between September 1984 and December 1988. During this period, the operative technique, the protocol for rehabilitation, and the regimen for prophylaxis against thromboembolism did not change meaningfully. The patients received either epidural or general anesthesia. Preoperative and postoperative perfusion scans of the lungs and a venogram of the lower limb or limbs that had been operated on were done for all patients. For the 227 patients who had received epidural anesthesia, the over-all rate of deep-vein thrombosis was 48 per cent, which was significantly lower than the 64 per cent incidence in the 264 patients who had received general anesthesia (p less than 0.0001). The greatest reduction was in the occurrence of proximal thrombosis, which was identified in 9 per cent of the patients who had had general anesthesia but in only 4 per cent of those who had had epidural anesthesia (p less than 0.05). The use of epidural anesthesia reduced the incidence of proximal thrombosis after both unilateral and one-stage bilateral arthroplasty.

Cardiac arrest during hip arthroplasty with a cemented long-stem component. A report of seven cases.

Seven patients had a cardiac arrest during hip arthroplasty with a cemented long-stem femoral component. Four patients died in the operating room, and three patients were successfully resuscitated. When the three survivors were eventually discharged from the hospital, they had no known permanent cardiac, pulmonary, or neurological sequelae. Factors that were common to all of the patients were advanced age, osteoporotic bone, a previously undisturbed intramedullary canal, and use of a long-stem femoral component and several batches of methylmethacrylate. Hip arthroplasty with a long-stem femoral component is associated with substantial risk in these patients. Excessive pressurization of cement should be avoided, and invasive hemodynamic monitoring should be used when the described conditions are present.

The effect of intravenous fixed-dose heparin during total hip arthroplasty on the incidence of deep-vein thrombosis. A randomized, double-blind trial in patients operated on with epidural anesthesia and controlled hypotension.

Heparin was given in fixed doses intravenously during unilateral primary total hip-replacement operations in a prospective, double-blind trial to assess the effect on the incidence of deep-vein thrombosis. One hundred and fifty patients were randomly assigned to one of two groups before the operation. Twenty-four patients were excluded from the study, leaving 126 patients. Group I consisted of sixty-six patients who received saline solution intravenously, and Group II comprised sixty patients who received heparin. All patients had epidural anesthesia with controlled hypotension. Fixed doses of heparin were administered five minutes before the operative incision was made and every thirty minutes throughout the operation. Mean arterial pressures were maintained at between fifty and sixty millimeters of mercury in all patients. Ascending venography was done on the seventh day after the operation. The incidence of deep-vein thrombosis was 24 per cent (sixteen of sixty-six patients) in Group I and 8 per cent (five of sixty patients) in Group II; the difference is significant (p = 0.03). The intraoperative loss of blood averaged 220 +/- 79 milliliters in Group I compared with 269 +/- 109 milliliters in Group II. An average of less than one unit of blood was transfused for each patient in each group. Postoperatively, there was no difference between the groups with regard to the amount of drainage that was collected in a Hemovac device or the values for hematocrit.

The prevalence of deep venous thrombosis after total hip arthroplasty with hypotensive epidural anesthesia.

A prospective, randomized trial was done to evaluate the prevalence of deep venous thrombosis following primary unilateral or bilateral total hip arthroplasty with use of hypotensive epidural anesthesia, external pneumatic-compression boots, and aspirin (Group I) and with use of hypotensive epidural anesthesia and aspirin (Group II). All operations were performed by two of us (E. A. S. and T. P. S.) through a posterolateral approach. Two hundred and thirty-one patients who were more than thirty-nine years old and who had a total of 250 primary total hip arthroplasties were included in the study. There were 113 patients (124 hips) in Group I and 118 patients (126 hips) in Group II. All patients had venography on the sixth, seventh, or eighth postoperative day. Group I had no proximal thrombi, seven distal thrombi (6 per cent), and one late pulmonary embolus (1 per cent). Group II had one proximal thrombus (popliteal) (1 per cent), eight distal thrombi (6 per cent), and one late pulmonary embolus (1 per cent). The difference was not significant (p = 0.65). However, a significant difference may have been noted if the study population had been larger. The combination of hypotensive epidural anesthesia and aspirin is effective prophylaxis against deep venous thrombosis in patients who have a primary total hip arthroplasty. The extremely low rate of deep venous thrombosis in the present study may be attributed to the use of hypotensive epidural anesthesia and the associated decrease in blood loss and transfusion requirements.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of hypotensive epidural anaesthesia on acetabular cement-bone fixation in total hip arthroplasty.

We selected 20 matched pairs of patients who had had total hip arthroplasty by the same surgeon using the same cemented technique. Matching was by age, sex, height, weight and diagnosis. One of each pair had received hypotensive epidural anaesthesia, with less than 300 ml blood loss: the other had normotensive general anaesthesia with more than 500 ml of blood loss. Early postoperative radiographs were evaluated independently by three blinded observers, using a scoring criteria which assessed the quality of the cement-bone interface. The results showed that patients who had received epidural anaesthesia had significantly better radiographic scores (p less than 0.02). Our findings suggest that hypotensive anaesthesia facilitates penetration of cement into bone.

Venous haemodynamics after total knee arthroplasty: evaluation of active dorsal to plantar flexion and several mechanical compression devices.

We performed a crossover study to evaluate the haemodynamic effect of active dorsal to plantar flexion and seven pneumatic compression devices in ten patients who had a total knee arthroplasty. Using the Acuson 128XP/10 duplex ultrasound unit with a 5MHz linear array probe, we assessed the augmentation of peak venous velocity and venous volume above and below the junction of the greater saphenous and common femoral veins in order to study both the deep and superficial venous systems. The pneumatic compression devices evaluated included two foot pumps (A-V Impulse System and PlexiPulse Foot), a foot-calf pump (PlexiPulse Foot-Calf), a calf pump (VenaFlow System) and three calf-thigh pumps (SCD System, Flowtron DVT and Jobst Athrombic Pump). The devices differed in a number of ways, including the length and location of the sleeve and bladder, the frequency and duration of activation, the rate of pressure rise, and the maximum pressure achieved. A randomisation table was used to determine the order of the test conditions for each patient. The enhancement of peak venous velocity occurred primarily in the deep venous system below the level of the saphenofemoral junction. The increases in peak venous velocity were as follows: active dorsal to plantar flexion 175%; foot pumps, A-V Impulse System 29% and PlexiPulse 65%; foot-calf pump, PlexiPulse, 221%; calf pump, VenaFlow, 302% and calf-thigh pumps, Flowtron DVT 87%, SCD System 116% and Jobst Athrombic Pump 263%. All the devices augmented venous volume, the greatest effect being seen with those incorporating calf compression. The increases in ml/min were found in the deep venous system as follows: foot pumps, A-V Impulse System 9.6 and PlexiPulse Foot 16.7; foot-calf pump, PlexiPulse, 38.1; calf pump, VenaFlow, 26.2; calf-thigh pumps, Flowtron DVT 61.5, SCD System 34.7 and Jobst Athrombic Pump 82.3. Active dorsal to plantar flexion generated 8.5 ml for a single calf contraction.

The impact of sports injuries in winter on medical services.

2529 injured sportsmen were treated at the Hutt and Wellington accident and emergency departments from 1 April to 31 August 1972. Almost two-thirds (62 percent) of these injuries were sustained during Saturday games, but only one-third (36.7 percent) of those injured presented on Saturdays. In view of the necessity to x-ray 75 percent, refer 18 percent to other hospital departments and admit 7.6 percent to hospital, a sports medicine clinic is suggested within the hospital complex. Such a clinic would ease the A and E work load and, at the same time, provide improved treatment for injured sportsmen.

Risk factors of sports injuries in winter.

During the winter season (1 April-31 August) of 1972, 2529 sporting injuries were treated in Wellington and Hutt Accident and Emergency Departments. A computerised analysis was made of the answers to a questionnaire filled out by each patient. Over 90 percent occurred playing major team sports, the majority while playing rugby (57 percent). The rate of injuries was found to be independent of the week of the season, socioeconomic status, race or position played, but was related to age, team sport, and grade played. The majority occurred during games in the weekend. Boys under 13 years of age are rarely injured whereas senior and older players are more frequently injured, especially in the second half of play. It is proposed that competition and the velocity of impact are important contributing factors in major sporting injuries.

Epidural infusions of bupivacaine and fentanyl do not improve rehabilitation following one-stage bilateral total knee arthroplasty.

Epidural analgesia with local anaesthetic minimizes the catabolic response to surgery. To determine whether this could enhance the rate of recovery following orthopaedic surgery, 51 patients undergoing bilateral one-stage total knee arthroplasty were allocated to receive infusions of either continuous epidural bupivacaine/fentanyl or continuous intravenous fentanyl to compare the efficacy of these modes of pain relief on postoperative clinical outcomes and rates of rehabilitation. Infusions were maintained for 36 to 48 hours in a post-anaesthesia care unit (PACU). Postoperatively, pain relief (visual analogue scale), attainment of physical therapy goals and cardiopulmonary complications were measured daily for 7 days. Epidural analgesia with a combination of bupivacaine and fentanyl did not result in any measurable improvement in rehabilitation milestones or reduction in postoperative complications following bilateral total knee arthroplasty than with fentanyl infusions alone.

Hypotensive epidural anaesthesia in patients with preoperative renal dysfunction undergoing total hip replacement.

BACKGROUND: Hypotensive anaesthesia does not impair renal function after surgery in normal patients but there are no reports of hypotensive anaesthesia in patients with chronic renal dysfunction (CRD). METHODS: From a database of 1893 consecutive patients undergoing total hip replacement (THR) under hypotensive epidural anaesthesia (HEA) from 1999 to 2004, 54 patients were identified with CRD (preoperative serum creatinine > or =124 micromol litre(-1)). Fifty matched pairs were identified for patients with normal renal function who have hypertension (n=50) or no hypertension (n=50). Changes in serum creatinine and blood urea nitrogen (BUN) were recorded daily for 3 days. Acute renal failure was defined as an increase in serum creatinine of 44 micromol litre(-1). RESULTS: The mean duration of hypotension (MAP<55 mm Hg) was 94 min (range 35-305 min). The mean age was 71 yr. All patients with a creatinine level of 124 micromol litre(-1) had a creatinine clearance of <40 ml min(-1) 1.73 m(-2) (range: 13-56). Patients with CRD received more crystalloid during surgery (1755 ml) than the other two groups (1435 ml) (P<0.001). Otherwise, all three groups were similar. No patients developed evidence of acute renal dysfunction immediately after or by 24 h after surgery. Three patients with CRD had an increase in creatinine of >44 micromol litre(-1) at 48 and 72 h after surgery in the setting of volume depletion (acute blood loss in two patients and early ileus in one). Renal function subsequently improved. CONCLUSION: HEA, per se, when carefully managed does not appear to predispose patients with CRD to acute renal failure after THR.

Recordings of, and an anatomical explanation for, false positive loss of resistance during lumbar extradural analgesia.

Loss of resistance dorsal to the ligamentum flavum was recorded in 10 of 16 patients aged 43--75 yr whilst performing extradural anaesthesia at the L2--3 interspace via the midline approach. Degeneration of the interspinous ligament with cavity formation is observed frequently in the elderly and may account for false positive loss of resistance and failure to obtain analgesia following the injection of local anaesthetic.

Update in regional anesthesia for shoulder surgery.

Recent advances in the application of regional anesthesia to the care of patients undergoing shoulder surgery are discussed. New techniques for the management of postoperative pain are highlighted, with an emphasis on interscalene patient-controlled analgesia and suprascapular block. New developments in the safety and effectiveness of brachial plexus block are presented. The technique of interscalene block used at our institution is discussed in detail. Intraoperative hypotension and bradycardia caused by activation of the Bezold-Jarisch reflex is considered. The ongoing debate regarding the use of paresthesia versus nerve-stimulator techniques is examined.

Pulse oximeter waveforms from the finger and toe during lumbar epidural anesthesia.

BACKGROUND AND OBJECTIVES: To determine whether lumbar epidural anesthesia affects pulse oximeter signals in the upper or lower extremity, 13 ASA I patients were studied. METHODS: Temperature and pulse oximeter probes were placed on the finger and the toe. RESULTS: After epidural injection, the amplitude of the pulse oximeter waveform on the toe increased eight-fold but declined by 50% in the finger. The increase in amplitude of the pulse oximeter waveform in the foot preceded the temperature rise. CONCLUSIONS: More reliable pulse oximeter signals may be obtained from the toe than the finger during lumbar epidural anesthesia. Furthermore, the increase in the pulse amplitude from the toe may aid in the early detection of successful epidural block.

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.