Optimal dose of intrathecal clonidine added to sufentanil plus bupivacaine for labour analgesia

PURPOSE: The combination of intrathecal (IT) 5 microg sufentanil plus 1.25 mg bupivacaine is useful for inducing labour analgesia, albeit of short duration and slow onset. As a supplementation to this regimen, the effect of IT clonidine on the duration of analgesic action was investigated. METHODS: Forty-eight healthy parturients were randomly assigned into three groups to receive 0 microg (group C0), 15 microg (C15) or 30 microg (C30) of clonidine IT in addition to 5 microg sufentanil plus 1.25 mg bupivacaine IT for labour analgesia. The quality of pain relief was assessed on 0-100 visual analogue scale by the author. The occurrence of side effects was also evaluated before the request for additional analgesia. RESULTS: Clonidine (C15 and C30), produced a longer duration of analgesia than C0 (mean 144 +/- sd 27.9, 165 +/- 31.8 vs 111 +/- 21.9 min, P < 0.01). Also, C15 and C30 produced a more rapid onset and a higher quality of analgesia than C0, (P < 0.01). The most cephalad level of sensory block was higher in C30 than C15 (median T3 vs T4, P < 0.05) but lowest in C0 (median T7 vs T3,T4, P < 0.01). Side effects, sedation and hypotension, occurred more frequently in C30 than in either C0 or C 15, (9 vs 2,5 and 9 vs 1,3, respectively, P < 0.05). CONCLUSION: The optimal dose of intrathecal clonidine to enhance labour analgesia with the current sufentanil-bupivacaine regimen is 15 microg. In view of the side effect profile, doses greater than 30 microg clonidine are unlikely to be useful.     

Evaluation of the usefulness of intrathecal bupivacaine infusion for analgesia after hip and knee arthroplasty

Spinal anaesthesia in 47 ASA I-III patients was induced with 0.5% bupivacaine 2 ml via a 28-gauge spinal catheter (L3-4 interspace) and 0.5-ml increments were given if needed before or during hip or knee arthroplasty. Intrathecal 24-h infusions consisted of 0.5% bupivacaine 0.4 ml h-1 (2 mg h-1) (n = 12), 0.5% bupivacaine 0.2 ml h-1 (1 mg h-1) (n = 12) or saline (n = 11) (12 exclusions). Patients received oxycodone 0.1-0.14 mg kg-1 i.m. for rescue analgesia. Infusion of bupivacaine 2 mg h-1 provided significantly better postoperative analgesia (19 oxycodone doses per group in 24 h) compared with bupivacaine 1 mg h-1 (36 doses of oxycodone per group) and saline (52 doses per group) (P < 0.05). Five patients in the bupivacaine 2-mg h-1 group and none in the other groups had measurable sensory block 24 h after the infusion was started. Three patients in the bupivacaine 2-mg h-1 group, two with concomitant arterial hypotension, and one patient in the bupivacaine 1-mg h-1 group experienced an increase in block on the ward. The incidence of nausea and vomiting was similar in all groups. Although an effective analgesic, intrathecal infusion of bupivacaine 2 mg h-1 cannot be recommended for routine pain relief because of the risk of increasing spinal block. Technical problems (19%) also reduced the overall efficacy of the continuous intrathecal analgesic regimen.      

Continuous intra-articular infusion of bupivacaine for postoperative pain following total knee arthroplasty

This study assessed the efficacy of local, continuous infusion of bupivacaine for pain control following total knee arthroplasty. Eleven men and 19 women with an average age of 65 years (range: 43-83 years) randomly received either 0.25% bupivacaine or normal saline by local infusion pump. Standard wound drainage also was implemented. Pain was assessed with a visual analog scale along with patient-controlled analgesia demand, narcotic delivery, and nonsteroidal anti-inflammatory administration. Drug lost to drainage also was assessed. Mean preoperative visual analog scores were similar between the saline and bupivacaine groups (6.5 +/- 1.4 and 6.1 +/- 2.0, respectively; P = .535). By the end of the second postoperative day, scores decreased to 3.4 +/- 3.2 for the saline group and 2.5 +/- 1.6 for the bupivacaine group. Although postoperative reductions were statistically significant (P = .007), the main treatment effect was not (P = .404). Mean narcotic demand and usage were 87 +/- 114.1 requests with usage of 11.8 +/- 12.3 mg for the saline group and 96 +/- 104.8 requests with usage of 7.5 +/- 3.8 mg for the bupivacaine group (P = .505). Cumulative ketorolac administration was 47 +/- 52.2 mg for the saline group and 83.6 +/- 64.9 mg for the bupivacaine group (P=.100). Hydrocodone-acetaminophen usage also was similar between the saline and bupivacaine groups (88 +/- 43.9 mg and 64.6 +/- 35 mg, respectively) (P = .112). Drug lost to drainage was estimated to be 27%. These findings suggest continuous local analgesic infusion after total knee arthroplasty does not offer significant improvements in either pain relief or medication use. Drug loss from drainage may exceed 25% and may compromise analgesic effectiveness.     

Optimal duration of prophylaxis for venous thromboembolism following total hip arthroplasty and total knee arthroplasty

Elective total hip arthroplasty and total knee arthroplasty are associated with a high risk of postoperative venous thromboembolism. Traditionally, antithrombotic prophylaxis has been administered during the hospital stay. However, with patients spending less time in the hospital after surgery, there is a need to continue thromboprophylaxis beyond hospital discharge. The current recommendation for prophylaxis in total joint arthroplasty patients is a minimum of 10 days, with extended prophylaxis up to 28 to 35 days following total hip arthroplasty. Prophylaxis with low-molecular-weight heparins for approximately 4 weeks following hip arthroplasty has resulted in clinically significant reductions in the incidence of venographically confirmed deep vein thrombosis. Currently, no data support extended thromboprophylaxis beyond 10 days following total knee arthroplasty. Using weighted risk factors to assess individual risk for venous thromboembolism can help the physician determine the optimal duration of prophylaxis.     

Epinephrine decreases the dose of hyperbaric bupivacaine necessary for tourniquet pain blockade during spinal anesthesia for total knee replacement arthroplasty

Purpose

We quantified the dose-sparing effect of epinephrine by comparing the median effective dose (ED₅₀) of intrathecal hyperbaric bupivacaine co-administered with epinephrine with the ED₅₀ of intrathecal hyperbaric bupivacaine alone.

Methods

Three groups were randomly generated from 162 patients undergoing total knee replacement arthroplasty under combined spinal and epidural anesthesia: Group B (bupivacaine), Group BE1 (bupivacaine plus epinephrine 100 μg), and Group BE2 (bupivacaine plus epinephrine 200 μg). Each group was further divided by bupivacaine doses of 6, 7, 8, 9, 10, or 11 mg. The anesthesia was defined as successful if a bilateral T12 sensory block occurred within 15 min, and no intraoperative epidural supplement was required. The ED₅₀ and ED₉₅ for successful anesthesia and successful tourniquet pain blockade were determined separately by probit regression analysis.

Results

The ED₅₀ and ED₉₅ of intrathecal hyperbaric bupivacaine for successful anesthesia were not different among the groups: the ED₅₀ values were 7.1 mg [95 % confidence interval (95 % CI) 6.0–8.0 mg] in Group B, 6.2 mg (95 % CI 4.8–7.2 mg) in Group BE1, and 6.3 mg (95 % CI 4.9–7.2 mg) in Group BE2. However, the ED₅₀ and ED₉₅ values for tourniquet pain control were significantly smaller in Groups BE1 and BE2 than in Group B: the ED₅₀ values were 7.2 mg (95 % CI 6.3–7.9 mg), 5.5 mg (95 % CI 4.1–6.3 mg), and 5.3 mg (95 % CI 3.7–6.2 mg) in Groups B, BE1, and BE2, respectively. The incidence of tourniquet pain was significantly lower in Groups BE1 and BE2 than in Group B. The time to patients’ requests for supplemental analgesia was significantly longer in Groups BE1 and BE2 than in Group B.

Conclusions

Intrathecal epinephrine did not decrease the dose of intrathecal hyperbaric bupivacaine required for successful anesthesia. However, it reduced the dose required for tourniquet pain blockade.     

Small-dose intrathecal clonidine and isobaric bupivacaine for orthopedic surgery: a dose-response study

We examined the dose-response relationship of intrathecal clonidine at small doses (相似文献   

Intra-articular morphine and/or bupivacaine in the management of pain after total knee arthroplasty

The purpose of this study was to determine if intra-articular injection of morphine or bupivacaine significantly decreased postoperative pain as well as the use of intravenous narcotics for pain relief in patients undergoing total knee arthroplasty (TKA). In a prospective, double-blind, randomized fashion, 105 patients undergoing TKA were divided into the following 4 groups defined by the intra-articular injection they received: group 1 (n = 27) received saline solution, group 2 (n = 26) received morphine sulfate (5 mg), group 3 (n = 24) received bupivacaine (50 mg), and group 4 (n = 28) received a combination of morphine sulfate and bupivacaine. The injections were administered immediately after wound closure by the Hemovac drainage tubing that remained clamped for 45 minutes after surgery to allow for absorption. Before surgery and at 2, 4, 6, 24, and 48 hours after surgery, pain intensity was recorded using a visual analog scale. Postoperative supplemental intravenous morphine and/or meperidine was administered via a patient-controlled analgesia device, and 24-hour drug usage was tabulated. Results were suggestive of a modest short-term reduction in pain scores in the morphine and bupivacaine treatment groups compared with placebo (saline); however, results were statistically significant only at 4 hours because of the great variability in the pain score data. The total amount of postoperative pain medication used in the first 24 hours after surgery was not statistically significant between the 4 treatment groups. Thus, the results put into question the benefit of postoperative intraarticular administration of morphine or bupivacaine in patients undergoing TKA.     

Rotating-hinge total knee for revision total knee arthroplasty

Rotating-hinge knee implants are used for revision total knee arthroplasty in patients with severe ligament instability and bone loss. This study evaluated the outcomes of a series of rotating-hinge knees. Thirty-one NexGen Rotating Hinge Knees (Zimmer, Warsaw, Indiana) were implanted in 29 patients (2 bilateral), with an average age of 72.8 years. Indications for surgery were aseptic loosening (n=23), septic loosenings (n=4), tibiofemoral instability (n=3), and wear (n=1). The Hospital for Special Surgery Knee Score and the Knee Society Roentgenographic Evaluation System were used. Statistical and cumulative survival rate analyses were performed. Average follow-up was 60.3 months (range, 32-100 months). The Hospital for Special Surgery Knee Score results indicated statistically significant improvement; the total score increased from 65.5 preoperatively to 88.4 postoperatively. Average range of motion increased from 90.9° preoperatively to 114.4° postoperatively. Radiographs showed no periprosthetic bone fractures or implant ruptures. Radiolucent lines were found in 20 of 26 patients and were progressive in 2 (both revised). Complications occurred in 10 patients. The rigidity of the hinge may be associated with a risk of aseptic loosening due to the increased stress transfer to the bone from the prosthesis through the locked hinge. Rotating-hinge knee implants provided acceptable mid-term outcomes for revision knee surgery with ligamentous instability. They are not at higher risk for early loosening unless short tibial stems are used. The high percentage of failures is more related to the complex surgery and to the status of the patients than to the hinged mechanism.     

Stiffness in total knee arthroplasty

Stiffness is a relatively uncommon complication after total knee arthroplasty. It has been defined as a painful limitation in the range of movement (ROM). Its pathogenesis is still unclear even if some risk factors have been identified. Patient-related conditions may be difficult to treat. Preoperative ROM is the most important risk factor, but an association with diabetes, reflex sympathetic dystrophy, and general pathologies such as juvenile rheumatoid arthritis and ankylosing spondylitis has been demonstrated. Moreover, previous surgery may be an additional cause of an ROM limitation. Postoperative factors include infections, arthrofibrosis, heterotrophic ossifications, and incorrect rehabilitation protocol. Infections represent a challenging problem for the orthopaedic surgeon, and treatment may require long periods of antibiotics administration. However, it is widely accepted that an aggressive rehabilitation protocol is mandatory for a proper ROM recovery and to avoid the onset of arthrofibrosis and heterotrophic ossifications. Finally, surgery-related factors represent the most common cause of stiffness; they include errors in soft-tissue balancing, component malpositioning, and incorrect component sizing. Although closed manipulation, arthroscopic and open arthrolysis have been proposed, they may lead to unpredictable results and incomplete ROM recovery. Revision surgery must be proposed in the case of well-documented surgical errors. These operations are technically demanding and may be associated with high risk of complications; therefore they should be accurately planned and properly performed.     

Hybrid total knee arthroplasty

A prospective study of a hybrid total knee arthroplasty (TKA) with an uncemented femoral component and cemented tibial and patellar components was performed to combine the advantage of a press-fit femur while avoiding the problems in uncemented tibial and patellar implants. A total of 329 posterior cruciate-preserving TKA were studied at an average of 4.7 years after surgery: 84% of the knees had at most mild or occasional pain, 68% had good or excellent knee scores, and 62% could walk more than 1000 m. The function scores were 40% good or excellent in this collective, with an average age of 69.4 years at surgery. The component position and alignment were biomechanically correct. Radiolucent lines were observed regularly at the edges of the tibial and femoral components. There were no revisions for aseptic loosening. Hybrid TKA provides good results comparable to cemented TKA.     

Noncemented total knee arthroplasty

Extensive animal experimentation has proven porous titanium fiber composite to be an effective interface for direct attachment of prosthetic devices via bone ingrowth. Titanium has demonstrated excellent biocompatibility in long-term primate experiments. Utilizing this technology, a cementless total knee system has been developed. A pilot study of 34 knees demonstrated the feasibility of anchoring the tibial component without cement. A totally cementless unconstrained total knee replacement was designed with porous titanium fiber composite interfaces. Retention of the posterior cruciate ligament was an essential part of the design. A large range of sizes was chosen to allow precise fitting of individual patients with distribution of load over the maximum surface available. Early clinical results have been very encouraging. Patients have achieved excellent pain relief, rapid return of function, and range of motion exceeding previous designs.     

Patella in total knee arthroplasty

The patella is a reliable guide to the success or failure of a total knee replacement. Patients who do not experience peripatellar symptoms or a patellar complication usually have a successful result. Conversely, peripatellar symptoms or complications usually reflect an underlying problem with surgical technique, component designs, or both. Current designs still do not replicate normal kinematics, and current instrumentation and techniques significantly alter the anatomy of the patellofemoral articulation in a substantial percentage of patients. Reproducing extensor mechanism balance and using components that provide adequate congruency and contact area through a physiologic arc of motion should lead to a successful result with minimal patellar symptoms or complications whether or not the patella is resurfaced. Attempting to achieve normal patellofemoral kinematics and minimize patellar complications has led to a better understanding of total knee arthroplasty.     

Anametric total knee arthroplasty

The early experience with the anametric knee prosthesis shows it to be effective in achieving the aims desired in total knee arthroplasty. Decreased pain and improved function have been noted in most patients, with relatively few complications. In osteoarthritics, patellar replacement increases the level of improvement. This prosthetic system has been improved by the addition of further sizes and additional tibial fixation options. Detailed long-term follow-up evaluation of these patients will be necessary to judge the effectiveness of the newly introduced design modifications.     

Unicompartmental total knee arthroplasty

This article traces the evolution of unicondylar design and examines its indications, common aspects of surgical technique independent of design, results, and complications. The dichotomy of opinion concerning unicompartmental knee arthroplasty may reflect differences in patient selection, prosthesis selection, and surgical technique.     

Revision total knee arthroplasty

Revision total knee arthroplasty presents numerous technical challenges and decisions for the operating surgeon. Preoperative planning includes critically reviewing radiographs and ordering necessary equipment, including prosthetic components, extraction devices, and bone graft materials. In some cases, surgical exposure requires the use of extensile exposure techniques. Component removal is facilitated by the use of appropriate tools (eg, specialized osteotomes) as well as by the patience to ensure preservation of host bone. Bone loss is managed with bone grafts or prosthetic augmentation. Attention to balancing the flexion and extension gaps is essential to avoid problems with instability as well as excessively constrained prosthetic components. Intramedullary stem extensions improve long-term clinical results. Intraoperative extensor mechanism complications can be avoided with meticulous surgical technique; late complications may require surgical intervention.     

Revision total knee arthroplasty

Revision total knee arthroplasty can be very successful if careful preoperative planning has been carried out and the surgeon is equipped to handle potential problems encountered with restoration of static alignment, stability, and deficient bone stock. Special femoral and tibial component extractors are indispensable tools. A high-speed burr is helpful. Posterior cruciate ligament-preserving prostheses often can be used, but prostheses with extra degrees of constraint must be available. Long-stemmed components for both the femoral and tibial sides should be available. Access to a bone bank to obtain allogeneic bone for grafting is essential. The surgeon must be familiar with techniques other than bone grafting for restoration of deficient stock, such as the use of bone screws and cement, custom-augmented components, and metal wedge spacers.