Dusanka Zaric

Effect of perioperative β blockade in patients with diabetes undergoing major non-cardiac surgery: randomised placebo controlled, blinded multicentre trial

Abstract Objectives To evaluate the long term effects of perioperative β blockade on mortality and cardiac morbidity in patients with diabetes undergoing major non-cardiac surgery. Design Randomised placebo controlled and blinded multicentre trial. Analyses were by intention to treat. Setting University anaesthesia and surgical centres and one coordinating centre. Participants 921 patients aged > 39 scheduled for major non-cardiac surgery. Interventions 100 mg metoprolol controlled and extended release or placebo administered from the day before surgery to a maximum of eight perioperative days. Main outcome measures The composite primary outcome measure was time to all cause mortality, acute myocardial infarction, unstable angina, or congestive heart failure. Secondary outcome measures were time to all cause mortality, cardiac mortality, and non-fatal cardiac morbidity. Results Mean duration of intervention was 4.6 days in the metoprolol group and 4.9 days in the placebo group. Metoprolol significantly reduced the mean heart rate by 11% (95% confidence interval 9% to 13%) and mean blood pressure by 3% (1% to 5%). The primary outcome occurred in 99 of 462 patients in the metoprolol group (21%) and 93 of 459 patients in the placebo group (20%) (hazard ratio 1.06, 0.80 to 1.41) during a median follow-up of 18 months (range 6-30). All cause mortality was 16% (74/462) in the metoprolol group and 16% (72/459) in the placebo group (1.03, 0.74 to 1.42). The difference in risk for the proportion of patients with serious adverse events was 2.4% (− 0.8% to 5.6%). Conclusions Perioperative metoprolol did not significantly affect mortality and cardiac morbidity in these patients with diabetes. Confidence intervals, however, were wide, and the issue needs reassessment. Trial registration Current Controlled Trials ISRCTN58485613 [controlled-trials.com.

A Comparison of Epidural Analgesia With Combined Continuous Femoral-Sciatic Nerve Blocks After Total Knee Replacement

Epidural analgesia remains the “gold standard” of pain relief after total knee replacement. However, peripheral nerve block is gaining popularity because the incidence of side effects may be reduced. Our study tests this postulate. Sixty patients were prospectively randomized to receive either epidural infusion or combined continuous femoral and sciatic nerve blocks. Ropivacaine 2 mg/mL plus sufentanil 1 &mgr;g/mL was given either epidurally or through the femoral nerve catheter, and ropivacaine 0.5 mg/mL was given through the sciatic nerve catheter using elastomeric infusers (delivering 5 mL/h for 55 h). The primary outcome measure was the total incidence of side effects (urinary retention and moderate to severe degrees of dizziness, pruritus, sedation, and nausea/vomiting on the first postoperative day). Intensity of motor blockade, pain at rest and on mobilization, and rehabilitation indices were also registered for 72 h. One or more side effects were present in 87% of patients in the epidural group whereas only 35% of patients in the femoral and sciatic block groups were affected on the first postoperative day (P = 0.0002). Motor blockade was more intense in the operated limb on the day of surgery and the first postoperative day in the peripheral nerve block group (P = 0.001), whereas the non-operated limb was more blocked in the epidural group on the day of surgery (P = 0.0003). Pain on mobilization was well controlled in both groups and there were no differences in the length of hospital stay. Rehabilitation indices were similar. The results demonstrate a reduced incidence of side effects in the femoral/sciatic nerve block group than in the epidural group on the first postoperative day.

Continuous Saphenous Nerve Block as Supplement to Single-dose Local Infiltration Analgesia for Postoperative Pain Management After Total Knee Arthroplasty

Background and Objectives Local infiltration analgesia (LIA) reduces pain after total knee arthroplasty without the motor blockade associated with epidural analgesia or femoral nerve block. However, the duration and efficacy of LIA are not sufficient. A saphenous nerve block, in addition to single-dose LIA, may improve analgesia without interfering with early mobilization. Methods Forty patients were included in this double-blind randomized controlled trial. All patients received spinal anesthesia for surgery and single-dose LIA during the operation. An ultrasound-guided saphenous nerve catheter was placed postoperatively in the adductor canal at midthigh level. Patients were randomized into 2 groups to receive 15-mL boluses of either ropivacaine 7.5 mg/mL or saline twice daily for 2 postoperative days. Results Worst pain scores during movement on the day of surgery were significantly lower in the ropivacaine group (median [range] visual analog scale, 3 [0–7] vs 5.5 [0–10]; P < 0.050), as well as pain at rest (visual analog scale, 2 [0–8] vs 4 [0–8]; P = 0.032). Breakthrough pain occurred later in the ropivacaine group (10.5 [range, 0.5–48] hours vs 3.4 [range, 0.5–24] hours; P = 0.011). All patients in the ropivacaine group were able to ambulate on the day of surgery versus 13 patients in the control group (P = 0.004). Fewer patients had sleep disturbance on the first postoperative night in the ropivacaine group (P = 0.038). We found no differences in morphine consumption. Conclusions The combination of a saphenous nerve block with single-dose LIA offered better pain relief on the day of surgery than LIA alone.

Transient neurologic symptoms after spinal anesthesia with lidocaine versus other local anesthetics : a systematic review of randomized, controlled trials

Lidocaine has been used for spinal anesthesia since 1948, seemingly without causing concern. However, during the last 10 years, a number of reports have appeared implicating lidocaine as a possible cause of neurologic complications after spinal anesthesia. Follow-up of patients who received uncomplicated spinal anesthesia revealed that some of them developed pain in the lower extremities—transient neurologic symptoms (TNS). In this study, we sought to compare the frequency of 1) TNS and 2) neurologic complications after spinal anesthesia with lidocaine with that after other local anesthetics. Published trials were identified by computerized searches of The Cochrane Library, MEDLINE, LILAC, and EMBASE and by checking the reference lists of trials and review articles. The search identified 14 trials reporting 1347 patients, 117 of whom developed TNS. None of these patients showed signs of neurologic complications. The relative risk for developing TNS after spinal anesthesia with lidocaine was higher than with other local anesthetics (bupivacaine, prilocaine, procaine, and mepivacaine), i.e., 4.35 (95% confidence interval, 1.98–9.54). There was no evidence that this painful condition was associated with any neurologic pathology; in all patients, the symptoms disappeared spontaneously by the 10th postoperative day.

Pharmacokinetics of ropivacaine and bupivacaine during 21 hours of continuous epidural infusion in healthy male volunteers

The aim of the present study was to evaluate the pharmacokinetics of ropivacaine and to compare the results with those of bupivacaine during prolonged epidural infusion.Ropivacaine 1, 2, or 3 mg/mL (0.1%, 0.2%, or 0.3%), bupivacaine 2.5 mg/mL (0.25%), or placebo (sodium chloride 0.9%) was given randomly and in a double-blind manner to five parallel treatment groups (37 healthy volunteers) as a continuous epidural infusion for 21 h. A 10-mL epidural bolus dose was first given, and the epidural infusion was started immediately afterward. The subjects received 10 mL/h corresponding to infusion rates of 10, 20, or 30 mg/h ropivacaine and 25 mg/h bupivacaine, respectively. Peripheral blood samples for measurements of ropivacaine or bupivacaine were taken during a 25-h period. The total plasma concentration increased continuously but seemed to reach a plateau (C5-10h) after approximately 5 h infusion, remaining fairly constant up to approximately 10 h after the start of administration. The C5-10h values were proportional to the dose of ropivacaine and were estimated as 0.3, 0.6, and 0.9 mg/L, and for bupivacaine as 0.7 mg/L. During the subsequent infusion the plasma concentration increased, with maximum plasma levels at the end of the infusion and with corresponding values of 0.4, 0.9, 1.2, and 0.9 mg/L. The highest individual plasma concentration was 1.7 mg/L (20 mg/h), and no patient showed signs of toxic systemic plasma levels. The free concentrations also increased continuously during the infusion. The free fraction was independent of the dose (6.1% for ropivacaine and 4.8% for bupivacaine). The pharmacokinetics of ropivacaine was linear in the studied range of infusion rates (up to total plasma concentrations of approximately 2 mg/L). (Anesth Analg 1995;81:1163-8)

Sensory and motor blockade during epidural analgesia with 1%, 0.75%, and 0.5% ropivacaine : a double-blind study

Levels of sensory (pinprick) and somatic motor blockade were measured in a double‐blind study of 30 volunteers given single epidural injections of 1%, 0.75%, and 0.5% ropivacaine. Onset of analgesia was rapid with all concentrations (7N–10 min). Maximal levels of analgesia were established 60 min after injection, with no significant differences in the maximal median cephalad spread. Duration of analgesia at the T-12 level and total duration were significantly longer with 1% and 0.75% than with 0.5% ropivacaine. Motor blockade was assessed by a quantitative method (measurements of isometric muscle force) and a qualitative method (modified Bromage scale). Onset of motor blockade measured by the quantitative method was significantly slower with 0.5% ropivacaine than with the higher concentrations. Maximal muscle weakness occurred 1–1.5 h after injection with all three concentrations. With increase in ropivacaine dose from 100 to 200 mg, the intensity and duration of motor blockade increased. Muscles involved in knee extension were blocked most, those of plantar flexion least. Recovery of motor function, assessed by the above‐mentioned quantitative method, occurred simultaneously with the recovery of pinprick perception. Motor blockade registered by Bromage scale showed a slower onset for 0.5% ropivacaine than for the higher concentrations. Mean durations of grade 1 and 2 block were longest for the 1% solution. Motor blockade described by the Bromage scale showed only the first part of the regression phase. Full recovery of muscle strength (Bromage scale = 0) was attained 1.5–2.5 h earlier than assessed by the quantitative method. No adverse effects were registered.

Adductor canal block or midthigh saphenous nerve block: same same but different name!

To the Editor: We read with great interest the inaugural section “Daring Discourse” by Tran et al regarding analgesia for clavicular fracture and surgery. We agree with the authors’ qualified endorsement of Dejerine’s description of dual innervation of the clavicle by both the cervical and brachial plexus. In our experience, the true measure of success for nerve blockade is efficacy for surgical anesthesia. To this end, we wish to report a recent case where surgical fixation of the clavicle was performed solely under combined superficial cervical plexus and supraclavicular brachial plexus blockade using a single-needle insertion. A 17-year-old male patient presented for open reduction and internal fixation of a displaced fracture of the left clavicle. With patient consent, ostensibly for a nerve block for postoperative analgesia, an ultrasoundguided superficial cervical plexus block was first performed with a 22-gauge, 50-mm insulated needle using an in-plane technique. Fifteenmilliliters of 0.5% ropivacaine and 0.125% bupivacaine [1:1] was injected deep to the prevertebral fascia between the sternocleidomastoid muscle and the anterior scalene muscle where the superficial cervical plexus traverses. The needle was then simply advanced to a location adjacent to the brachial plexus at a low interscalene location. Five milliliters of the same solution was deposited at this location (Fig. 1). Within 10 minutes of block completion, the patient had lost temperature sensation from the mandibular angle to the C5 dermatome of the anterior chest wall. Contemporaneously, he developed a complete motor block of the upper limb. This was deemed satisfactory anesthesia for the surgical procedure and the patient subsequently consented to an awake procedure. Performed in the beach chair position, the procedure lasted for 105 minutes. The patient reported being comfortable throughout the surgery. Despite no clinical evidence of respiratory distress, this combination of nerve blocks will undoubtedly lead to phrenic nerve blockade. We agree with Tran et al’s call for further clarification of the sensory innervation of the clavicle. A successful practice in ultrasound-guided regional anesthesia is based on a solid understanding of conventional anatomy. Occasionally, sonoanatomy may reciprocate and contribute to our existing knowledge.

Reply to Dr Chelly.

our article on fascia iliaca block for analgesia after hip arthroplasty. To properly interpret our findings, it is important to keep in mind the following 2 considerations. First, we did not compare the analgesic efficacy of different techniques. Second, the technique described in our study has been used for the same indication for decades. Because we used ultrasound monitoring, we believe that our technique was more precise than that in the era of double pop technique. Therefore, we simply put a traditional technique commonly used for this indication to an objective, analgesic test. We agree with Murgatroyd et al in that type II error was possible in our study. However, this possibility should be considered within the context of clinical significance/reality. We tested analgesic efficacy of an invasive interventional technique expected to be highly effective, much like interscalene block after shoulder surgery or popliteal block after foot surgery. Increasing the sample size would have decreased the chance of type II error, but would not benefit the study patients. Finally, as discussed in our publication, different techniques and/or pharmacological choices could have indeed resulted in a different analgesic outcome in patients after hip replacement. Therefore, we appreciate the discussion on the various technical aspects of fascia iliaca blocks as detailed by Murgatroyd et al. Although the various technical modifications seem to make anatomical sense, we do not know whether such will translate into analgesic benefit without proper randomized controlled trials, given the complex innervation of the hip with contributions from the sciatic, femoral, and obturator nerves. We hope that the communicated findings of our research will fuel more research efforts regarding optimal analgesia for hip surgery. Ali Shariat, MD Department of Anesthesiology St Luke’s-Roosevelt Hospital Center Columbia University College of Physicians and Surgeons New York, NY