Stephan Blumenthal

Adrenergic receptor genotype but not perioperative bisoprolol therapy may determine cardiovascular outcome in at-risk patients undergoing surgery with spinal block: the Swiss Beta Blocker in Spinal Anesthesia (BBSA) study: a double-blinded, placebo-controlled, multicenter trial with 1-year follow-up

Background:Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block. Methods:The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined. Results:A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55–1.69; P = 0.90). However, carriers of at least one Gly allele of the β1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04–3.35; P = 0.04). Conclusions:Perioperative bisoprolol therapy did not affect cardiovascular outcome in these elderly at-risk patients undergoing surgery with spinal block.

Double Epidural Catheter with Ropivacaine versus Intravenous Morphine: A Comparison for Postoperative Analgesia after Scoliosis Correction Surgery

Background: Major spine surgery with a dorsal or ventrodorsal approach causes severe postoperative pain. The use of continuous epidural analgesia through one or two epidural catheters placed intraoperatively by the surgeon has been shown to provide efficient postoperative pain control. In this prospective unblinded study, the authors compared the efficacy of continuous intravenous morphine with a continuous double epidural catheter technique with ropivacaine after scoliosis correction. Methods: Thirty patients with American Society of Anesthesiology physical status I-III were prospectively randomized to either the morphine group or the epidural group. At the end of surgery, patients in the epidural group received two epidural catheters placed by the surgeon, one directed cephalad and one caudally. Correct placement was checked radiographically. Postoperative analgesia until the first postoperative morning was performed with remifentanil target-control infusion for all patients. From that time remifentanil was stopped and continuous intravenous analgesia with morphine or double epidural analgesia with ropivacaine 0.3% was initiated (T o = beginning of study). Pain at rest and pain in motion (using a visual analog scale from 0-100), the amount of rescue analgesics, sensory level, motor blockade, postoperative nausea and vomiting, and pruritus were assessed every 6 h and bowel function was assessed every 12 h until T 72 (end of study). Two days later, patient satisfaction was assessed. Results: Pain scores at rest were significantly decreased in the epidural group at all time points except at T 12 , T 60 , and T 72 . Pain scores in motion were significantly decreased in the epidural group at T 24 , T 40 , and T 72 . Bowel activity was significantly better in the epidural group at T 24 , T 36 , T 48 , and T 60 . Postoperative nausea and vomiting and pruritus occurred significantly less frequently in the epidural group. No complications related to the epidural catheter occurred. Conclusions: Both methods provide efficient postoperative analgesia. However, double epidural catheter technique provides better postoperative analgesia, earlier recovery of bowel function, fewer side effects, and a higher patient satisfaction.

Continuous Infusion of Ropivacaine for Pain Relief after Iliac Crest Bone Grafting for Shoulder Surgery

Background:The aim of the study was to compare the efficacy of either ropivacaine or placebo through an iliac crest (IC) catheter after Bankart repair with IC bone grafting. Methods:With approval of the local ethics committee and after written informed consent was obtained, 36 patients had an interscalene catheter placed preoperatively. Intraoperatively, the surgeon placed a catheter at the IC donor site. At the end of surgery, 30 ml ropivacaine, 0.5% (ropivacaine group), or 30 ml NaCl, 0.9% (placebo group), was administered. Ropivacaine, 0.2%, was started 6 h after the initial block through the interscalene catheter for 48 h (t48) in all patients. At t0, the patient received either 5 ml/h ropivacaine, 0.2% (ropivacaine group), or 5 ml/h NaCl, 0.9% (placebo group), for 48 h through the IC catheter. All patients received an intravenous morphine patient-controlled analgesia device. Pain scores at the shoulder and at the IC donor site were assessed at rest and during motion every 8 h for 48 h and after 3 months. Plasma concentrations of total and unbound ropivacaine, morphine consumption, and patient satisfaction were assessed. Results:At the IC donor site, pain was significantly lower in the ropivacaine group compared with the placebo group at rest and during motion at any time. Total and unbound plasma concentrations of ropivacaine were below the toxic threshold in both groups. Morphine consumption was significantly lower in the ropivacaine group after 24 and 48 h. Patient satisfaction was significantly higher in the ropivacaine group. At 3 months, pain at the IC during motion was significantly lower in the ropivacaine group. Conclusions:Continuous application of 0.2% ropivacaine through an IC catheter after Bankart repair with IC bone grafting is an effective method for pain relief for the first 48 h, with few adverse effects and high patient satisfaction. The benefit of this technique is still present after 3 months.

The feasibility and complications of the continuous popliteal nerve block : A 1001-case survey

Perineural catheters are increasingly used worldwide for the treatment of postoperative pain in orthopedics. Long-term complications associated with the placement of a perineural catheter remain largely unstudied. We investigated the efficacy and the acute and late complications associated with the continuous popliteal nerve block. One-thousand-one patients undergoing elective surgery of the ankle or foot and scheduled to have a continuous popliteal nerve block were prospectively evaluated. All patients received an initial bolus of 40 mL ropivacaine 0.5% through the catheter. A continuous infusion of ropivacaine 0.3% initiated 6 h after the initial bolus was administered for the first 24 h and then decreased to ropivacaine 0.2% until the end of the study period. The success rate and acute complications were recorded. The overall success rate was 97.5%. The highest success rate was associated with foot inversion. Acute complications consisted of paresthesias during nerve localization (0.5%), pain during local anesthetic application (0.8%), and blood aspiration (0.4%). No central nervous system toxicity or cardiotoxicity occurred. Late complications were checked at 10 days and 3 mo after surgery. These included two cases of inflammation at the puncture site. No infection or neuropathy was observed. The use of continuous popliteal nerve block for ankle or foot surgery is associated with frequent success and few acute and late complications.

Postoperative intravenous morphine consumption, pain scores, and side effects with perioperative oral controlled-release oxycodone after lumbar discectomy.

BACKGROUND: Oral opioid formulations contribute to postoperative analgesia. In this study, we evaluated the perioperative application of oral controlled-release oxycodone to reduce postoperative IV morphine consumption and opioid side effects after lumbar discectomy. METHODS: Forty patients scheduled for elective lumbar discectomy over 1 or 2 levels were included in this prospective, randomized, double-blind, placebo-controlled study. Every 12 h patients received either 20 mg oral controlled-release oxycodone or placebo, from the evening before surgery until the second postoperative morning. All patients received IV morphine via a morphine patient-controlled analgesia device for postoperative analgesia. Acetaminophen 1 g was administered to all patients every 6 h. Postoperative IV morphine consumption was assessed separately for T0–T24 and T24–T48. Postoperative assessments were conducted every 6 h for the first 48 h after surgery. Postoperative analgesia assessments included pain at rest, during coughing, and with motion, using a visual analog scale. Nausea, vomiting, pruritus, sedation, and bowel function were also assessed every 6 h. Patients rated their satisfaction with postoperative analgesia 72 h postoperatively. RESULTS: Postoperative IV morphine consumption was significantly reduced during T0–T24 (26 ± 10 mg vs 52 ± 29 mg) and T24–T48 (13 ± 8 mg vs 33 ± 18 mg) in the controlled-release oxycodone group compared with that in the placebo group. Pain scores at rest, during coughing, and with motion were significantly lower during the first 48 postoperative hours in the controlled-release oxycodone group. Postoperative nausea and vomiting were significantly reduced during the first 24 h in the controlled-release oxycodone group. Lastly, the controlled-release oxycodone group also experienced significantly earlier recovery of bowel function and had higher patient satisfaction with pain therapy. CONCLUSIONS: Perioperative oral controlled-release oxycodone reduces postoperative IV morphine consumption after lumbar discectomy while providing good analgesia with fewer side effects compared with placebo.

Ropivacaine decreases inflammation in experimental endotoxin-induced lung injury.

Background: Endotoxin causes acute lung injury, which can lead to acute respiratory distress syndrome. Because local anesthetics are known to attenuate inflammatory reactions, ropivacaine was tested for its possible antiinflammatory effect in lipopolysaccharide-induced lung injury in rat alveolar epithelial cells (AECs) and rat pulmonary artery endothelial cells (RPAECs) in vitro and in vivo. Methods: AECs and RPAECs were stimulated for 4 h with lipopolysaccharide or lipopolysaccharide and 1 μM ropivacaine. Messenger RNA (mRNA) for intercellular adhesion molecule 1 was assessed. Isolated neutrophils were incubated with stimulated target cells to quantify adhesion and neutrophil-induced cytotoxicity in AECs and RPAECs. In vivo, lipopolysaccharide was instilled intratracheally with or without 1 mM intratracheally or intravenously administered ropivacaine. Bronchoalveolar lavage was performed 5 h later to determine neutrophil and albumin content, as well as concentrations of inflammatory mediators. Results: In AECs and RPAECs, ropivacaine attenuated lipopolysaccharide-induced up-regulation of mRNA for intercellular adhesion molecule 1 by 41% and 24%, respectively (P < 0.05). In the presence of ropivacaine, increased neutrophil adhesion was down-regulated by 58% and 44% (P < 0.005), whereas cytotoxicity in AECs and RPAECs was diminished by 28% and 33%, respectively (P < 0.05). Enhanced neutrophil count in lipopolysaccharide lungs was reduced by 56% in the presence of intratracheally instilled ropivacaine (81% with intravenous ropivacaine; P < 0.005). Albumin was decreased by 46% with intratracheal ropivacaine (38% with intravenous ropivacaine; P < 0.05), and inflammatory mediators were decreased by 48-59% (69-81% with intravenous ropivacaine; P < 0.01). Conclusions: Ropivacaine intervention substantially attenuated the inflammatory response in acute lung injury and thus may carry an interesting potential for antiinflammatory treatment.

Video-assisted thoracoscopic volume reduction surgery in patients with diffuse pulmonary emphysema : Gas exchange and anesthesiological management

Arterial blood gases were studied prospectively using continuous intraarterial blood gas monitoring during thoracoscopic volume reduction surgery (VRS) in 24 patients with advanced diffuse pulmonary emphysema.Additionally, the early postoperative course (48 h) of arterial blood gases was studied retrospectively. Twenty-six operations were performed using a combination of thoracic epidural and general anesthesia with left-sided double-lumen intubation for one-lung ventilation (OLV). Arterial blood gases were determined awake, during two-lung ventilation prior to surgery, during OLV (extreme values), and after tracheal extubation. Additionally, the extremes during the whole procedure were determined: avoiding excessive peak inspiratory pressures (26.4 +/- 7.0 cm H2 O), minimum PaO2 was 77 +/- 39 mm Hg (mean +/- SD), maximum PaCO2 65 +/- 14 mm Hg (P < 0.0001 versus preoperative values), and minimum pHa 7.22 +/- 0.08 (P < 0.0001). One tension pneumothorax occurred during OLV. Immediate postoperative extubation was performed in 25 of 26 cases, reintubation was necessary in two cases. One patient with coronary artery disease died 36 h after surgery. Hypercapnia (maximum PaCO2 49 +/- 8 mm Hg, minimum pHa 7.37 +/- 0.04, P < 0.01) was still observed 48 h after surgery. These results demonstrate that adequate oxygenation can be preserved during OLV for VRS, but CO2 elimination is impaired. However, intraoperative hypercapnia and immediate postoperative tracheal extubation are well tolerated. (Anesth Analg 1997;84:845-51)

The immunomodulatory effect of sevoflurane in endotoxin-injured alveolar epithelial cells

BACKGROUND:Endotoxin-induced lung injury is a useful experimental system for the characterization of immunopathologic mechanisms in acute lung injury. Although alveolar epithelial cells (AEC) are directly exposed to volatile anesthetics, there is limited information about the effect of anesthetics on these cells. In this study we investigated the effect of pretreatment with the inhaled anesthetic sevoflurane on lipopolysaccharide (LPS)-injured AEC. METHODS:AEC were incubated with 1.1 vol % sevoflurane for 0.5 h, followed by LPS stimulation for 5 h. Expression of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1β (MIP-1β), macrophage inflammatory protein-2 (MIP-2), cytokine-induced neutrophil chemoattractant-1 (CINC-1), and intercellular adhesion molecule-1 (ICAM-1) was analyzed. In addition, functional tests were performed through chemotaxis and adherence assays to underline the biological relevance of the findings. RESULTS:Exposure of AEC to sevoflurane resulted in a 50% downregulation of MCP-1 protein in the sevoflurane-LPS group when compared with non-sevoflurane- LPS cells (P < 0.05). MIP-1β concentration in LPS-stimulated cells decreased by 32% with sevoflurane (P < 0.05), MIP-2 by 29% (P < 0.05), and CINC-1 by 20% (P < 0.05). ICAM-1 protein expression was attenuated by 36% (P < 0.05). This inhibition caused substantial changes in the inflammatory response of neutrophils. 33% less chemotactic activity was seen in sevoflurane-treated LPS cells (P < 0.001) as well as 47% decreased adhesion of neutrophils to AEC (P < 0.001). CONCLUSIONS:This study shows that sevoflurane alters the LPS-induced inflammatory response, not only with respect to the expression pattern of inflammatory mediators, but also regarding the biological consequences with less accumulation of effector cells such as neutrophils.

Clinical evaluation of a modified posterior anatomical approach to performing the popliteal block

Background: Tibial and common peroneal nerves can be blocked by the posterior approach to the popliteal fossa. Techniques using fixed measured distances between knee skin crease and puncture point have been described. We report on an approach that is based on manual identification of the apex of the popliteal fossa. Methods: Five-hundred patients undergoing surgery of ankle or foot were prospectively included. The apex of the popliteal fossa (determined by the crossing point of the biceps femoris and the semitendinosus and semimembranosus muscles) was assessed by manual palpation. The puncture point was 0.5 cm below the apex, on the medial side of the biceps femoris muscle. When indicated for postoperative analgesia, a perineural catheter was placed. We assessed success rate, number of attempts, the distance between knee skin crease and the apex of the popliteal fossa, nerve depth, and acute and late complications. Results: Block success rate was 94% and 92% when the block was performed through the needle and the catheter, respectively. Inversion was the motor response with the highest success rate. The first attempt was successful in 97.5% of the patients. Mean depth of the nerve was 4.5 cm (range, 2.0 to 7.0 cm) and mean knee skin crease to apex of popliteal fossa distance was 9 cm (range, 7.0 to 12.0 cm). Nine patients (2%) had acute complications. There were no technical problems associated with the perineural nerve catheter. After 12 weeks, no late complications were observed. Conclusions: The modified posterior anatomical approach for popliteal sciatic nerve block is easy to perform, has a high success rate, and has a low complication rate. The location of the needle insertion point is assessed without any measurement, thus avoiding inaccuracies caused by repeated skin-distance measurements.

Preexisting Subclinical Neuropathy as a Risk Factor for Nerve Injury after Continuous Ropivacaine Administration through a Femoral Nerve Catheter

NERVE injury is a well-recognized complication of peripheral nerve blocks. Capdevila et al. reported an incidence of 0.21% in a large prospective multicenter study including more than 1,400 patients with perineural catheters. Beside factors related to the regional anesthesia technique, other causes such as concomitant patient disease, inadequate positioning or manipulation during surgery, and the neurotoxicity of local anesthetics have been implicated. We report on a patient who developed a femoral neuropathy after continuous femoral block. The only risk factor found in this patient was a postoperatively discovered, preexisting subclinical polyneuropathy.