The Impact of Regional Anesthesia in Masking Acute Compartment Syndrome after Limb Trauma.

Regional anesthesia has shown to be successful in controlling major pain in trauma patients. However, the possibility of masking acute compartment syndrome (ACS) after peripheral nerve blocks for limb injuries is still controversially discussed. Therefore, we aimed to summarize the current literature regarding this topic to shed light on the impact of peripheral regional anesthesia on the diagnosis of ACS in trauma patients. We searched Pubmed, Google Scholar and the Cochrane Library for literature following the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. The analysis of these reports was included in the context of the current literature concerning this topic. We found no (randomized) studies, and only six case reports dealing with the impact of peripheral nerve blocks and ACS in patients after a limb trauma met our criteria and were included in our review. Only one reported a delay in the diagnosis of ACS. In most of the cases (5 of 6), the breakthrough pain, despite the nerve block, proved to be a good indicator of a developing ACS. However, despite some narrative articles about the topic including some recommendations about the possibly safe use of regional anesthesia techniques for limb trauma, there is still no international consensus and only one national guideline focusing on the possibly safe use of peripheral nerve blocks in trauma patients at risk of ACS. After reviewing the respective literature, we consider that intra-articular analgesia, sensory blocks, fascial plane blocks and low-concentration continuous peripheral nerve blocks are effective for analgesia and a low-risk analgesia tool for trauma and postsurgical patients at risk of ACS due to the fact that they do not lead to a dense block. Finally, we summarized suggestions based on the results of the literature for the different regional anesthesia modalities in these patients in a table to facilitate the use of these techniques.

Effects of enhanced adsorption haemofiltration versus haemoadsorption in severe, refractory septic shock with high levels of endotoxemia: the ENDoX bicentric, randomized, controlled trial.

BACKGROUND: Endotoxin adsorption is a promising but controversial therapy in severe, refractory septic shock and conflicting results exist on the effective capacity of available devices to reduce circulating endotoxin and inflammatory cytokine levels. METHODS: Multiarm, randomized, controlled trial in two Swiss intensive care units, with a 1:1:1 randomization of patients suffering severe, refractory septic shock with high levels of endotoxemia, defined as an endotoxin activity ≥ 0.6, a vasopressor dependency index ≥ 3, volume resuscitation of at least 30 ml/kg/24 h and at least single organ failure, to a haemoadsorption (Toraymyxin), an enhanced adsorption haemofiltration (oXiris) or a control intervention. Primary endpoint was the difference in endotoxin activity at 72-h post-intervention to baseline. In addition, inflammatory cytokine, vasopressor dependency index and SOFA-Score dynamics over the initial 72 h were assessed inter alia. RESULTS: In the 30, out of 437 screened, randomized patients (10 Standard of care, 10 oXiris, 10 Toraymyxin), endotoxin reduction at 72-h post-intervention-start did not differ among interventions (Standard of Care: 12 [1-42]%, oXiris: 21 [10-51]%, Toraymyxin: 23 [10-36]%, p = 0.82). Furthermore, no difference between groups could be observed neither for reduction of inflammatory cytokine levels (p = 0.58), nor for vasopressor weaning (p = 0.95) or reversal of organ injury (p = 0.22). CONCLUSIONS: In a highly endotoxemic, severe, refractory septic shock population neither the Toraymyxin adsorber nor the oXiris membrane could show a reduction in circulating endotoxin or cytokine levels over standard of care. Trial registration ClinicalTrials.gov. NCT01948778. Registered August 30, 2013. https://clinicaltrials.gov/study/NCT01948778.

The beach chair position for shoulder surgery in intravenous general anesthesia and controlled hypotension: Impact on cerebral oxygenation, cerebral blood flow and neurobehavioral outcome.

STUDY OBJECTIVES: The aim of this study was to assess the impact of intravenous general anesthesia and controlled hypotension on cerebral saturation (rScO2), cerebral blood flow measured as middle cerebral artery blood flow velocity (Vmax MCA) and neurobehavioral outcome in patients scheduled for shoulder surgery in beach chair position. DESIGN: Prospective, assessor-blinded observational study. SETTING: University hospital, shoulder surgery operating room. PATIENTS: Forty ASA I-II patients scheduled for shoulder surgery in beach chair position and controlled hypotension. INTERVENTIONS: Neurological and neurobehavioral tests were performed prior and the day after surgery. The baseline data for near-infrared spectroscopy, bispectral index, cerebral blood flow, PaCO2 and invasive blood pressure (radial artery) were taken prior anesthesia and after anesthesia induction, after beach chair positioning and all 20 min after surgery start until discharge of the patient. MEASUREMENTS: Neurological and neurobehavioral tests, cerebral saturation (rScO2) using near-infrared spectroscopy, BIS, cerebral blood flow using Doppler of the middle cerebral artery (Vmax MCA), PaCO2 and invasive blood pressure assessed at heart and at the external acoustic meatus level. MAIN RESULTS: The incidence of cerebral desaturation events (CDEs) was 25%. The blood pressure drop 5 min after beach chair position measured at the acoustic meatus level in the CDE group was higher compared to patients without CDEs (p = 0.009) as was the rScO2 (p = 0.039) and the Vmax MCA (p = 0.002). There were no neurological deficits but patients with CDEs showed a greater negative impact on neurobehavioral tests 24 h after surgery compared to patients without CDEs (p = 0.001). CONCLUSIONS: In ASA I-II patients intravenous general anesthesia and controlled hypotension in the beach chair position affects cerebral blood flow and cerebral oxygenation with impact on the neurobehavioral outcome.

Influence of skin disinfection prior removal of perineural catheter on bacterial colonization, contamination and local inflammation: a prospective randomized study.

BACKGROUND: There is a wide variation of perineural catheter (PNC) colonization rates in the literature. The impact of skin disinfection on PNC colonization and inflammation is not clear. The objective of this prospective, randomized clinical study was to investigate the influence of alcoholic skin disinfection before PNC removal on the detection of bacteria on PNC. METHODS: Two hundred patients receiving a PNC for orthopedic surgery were randomized to receive (with-group) or not (without-group) a skin disinfection with a sprayed alcoholic solution before removal of the PNC. Bacterial colonization and contamination of the PNC and clinical signs of inflammation and infection of the PNC insertion site were evaluated. Skin disinfection with a sprayed alcoholic solution and sterile removal of the distal and subcutaneous part of the PNC was performed after 72 hours or earlier if signs of infection occurred with semiquantitative culture and enrichment culture of both parts. RESULTS: Alcoholic skin disinfection before PNC removal significantly reduced bacterial colonization with a reduction from 28% to 14% and from 32% to 17% for the tip and the subcutaneous part of the PNC, respectively (P<0.05). Clinical signs of inflammation at the PNC insertion site were similar (73%) in the two groups. The detection of colonization in 54 (27%) out of 200 PNC did not correlate with clinical signs of inflammation independently of the number of bacteria isolated. Redness was noted in 71% and 68% of patients in the without- and with-alcoholic skin disinfection-group respectively. Local pain on pressure was present in 28% and 19% in the without- and with-group respectively. CONCLUSIONS: Alcoholic skin disinfection before PNC removal reduced the detection of PNC colonisation by 50%. There was no correlation between clinical signs of inflammation and PNC colonization.

Extracorporeal Membrane Oxygenation for Treatment of Acute Inverted Takotsubo-Like Cardiomyopathy From Hemorrhagic Pheochromocytoma in Late Pregnancy.

We describe the first case of a pregnant woman presenting with an acute inverted takotsubo-like cardiomyopathy caused by a postpartum diagnosed hemorrhagic pheochromocytoma, successfully treated with percutaneous venoarterial extracorporeal membrane oxygenation (va-ECMO). During admission, an emergency cesarean delivery had to be performed. The fetus needed resuscitation for 5 minutes. The mother was successfully resuscitated and treated with percutaneous va-ECMO for 7 days. Despite advances in diagnostic techniques during the past decade, in many cases, pheochromocytoma in pregnancy is still missed. This results in a maternal and fetal mortality rate of up to 30% in both.

The length of stay in the post-anaesthesia care unit correlates with pain intensity, nausea and vomiting on arrival.

BACKGROUND: The benefit of the post-anaesthesia care unit (PACU) with respect to an early detection of postoperative complications is beyond dispute. From a patient perspective, prevention and optimal management of pain, nausea and vomiting (PONV) are also of utmost importance. The aims of the study were therefore to prospectively measure pain and PONV on arrival to the PACU and before discharge and to determine the relationship of pain and PONV to the length of stay in the PACU. METHODS: Postoperative pain was assessed over 30 months using a numeric rating scale on admittance to the PACU and before discharge; in addition, PONV was recorded. Statistical analysis was done considering gender, age, American Society of Anesthesiologists (ASA) classification, surgical speciality, anaesthesia technique, duration of anaesthesia, intensity of nursing and length of stay. RESULTS: Data of 12,179 patients were available for analysis. The average length of stay in the PACU was 5.7 ± 5.9 h, whereas regular PACU patients stayed for 3.2 ± 1.9 h and more complex IMC patients stayed for 15.1 ± 6.0 h. On admittance, 27% of patients were in pain and the number decreased to 13% before discharge; 3% experienced PONV. Risk factors for increased pain determined by multivariate analysis were female gender; higher ASA classification; general, cardiac and orthopaedic surgery and prolonged case duration. In more complex IMC patients, pain scores were higher on arrival but dropped to similar levels before discharge compared to regular PACU patients. Female gender and postoperative pain were risk factors for postoperative vomiting. Pain and PONV on arrival correlated with length of stay in the PACU. Pain- or PONV-free patients stayed almost half of the time in the PACU compared to patients with severe pain or vomiting on arrival. CONCLUSIONS: The majority of PACU patients had good pain control, both on admittance and before discharge, and the overall incidence of PONV was low. Managing patients in the PACU could achieve a significant reduction of pain and PONV. The level of pain and presence of PONV on admittance to the PACU correlate with and act as predictors for increased length of PACU stay.

Elevated CSF histamine levels in multiple sclerosis patients.

BACKGROUND: Histamine is an ubiquitous inflammatory mediator of numerous physiological processes. Histamine and its receptors have been implicated in multiple sclerosis (MS) disease pathogenesis. We prospectively enrolled 36 MS patients and 19 age and gender-matched healthy volunteers for cerebrospinal fluid (CSF) histamine analysis. FINDINGS: CSF HISTAMINE LEVELS IN MS PATIENT SAMPLES WERE SIGNIFICANTLY HIGHER (MEDIAN: 35.6 pg/ml) than in controls (median: 5.5 pg/ml; Beta = 0.525, p < 0.001). In addition, histamine increased with age (Pearson's correlation, p < 0.003). CONCLUSIONS: Histamine may be an important factor for both the initiation and maintenance of chronic inflammatory diseases of the central nervous system. Our observation encourages a deeper investigation of the role of histamine in MS.

In Zucker diabetic fatty rats, subclinical diabetic neuropathy increases in vivo lidocaine block duration but not in vitro neurotoxicity.

BACKGROUND AND OBJECTIVES: Application of local anesthetics may lead to nerve damage. Increasing evidence suggests that risk of neurotoxicity is higher in patients with diabetic peripheral neuropathy. In addition, block duration may be prolonged in neuropathy. We sought to investigate neurotoxicity in vitro and block duration in vivo in a genetic animal model of diabetes mellitus type 2. METHODS: In the first experiments, neurons harvested from control Zucker diabetic fatty (ZDF) rats were exposed to acute (24 hours) or chronic (72 hours) hyperglycemia, followed by incubation with lidocaine 40 mM (approximately 1%). In a second experiment, neurons harvested from control ZDF rats, or diabetic ZDF rats, were incubated with lidocaine, with or without SB203580, an inhibitor of the p38 mitogen-activated protein kinase. Finally, we performed sciatic nerve block (lidocaine 2%, 0.2 mL) in control or diabetic ZDF rats and measured motor and nociceptive block duration. RESULTS: In vitro, neither acute nor chronic hyperglycemia altered neurotoxic properties of lidocaine. In vitro, incubation of neurons with lidocaine resulted in a slightly decreased survival ratio when neurons were harvested from diabetic (57% ± 19%) as compared with control (64% ± 9%) rats. The addition of SB203580 partly reversed this enhanced neurotoxic effect and raised survival to 71% ± 12% in diabetic neurons and 66% ± 9% in control rats, respectively. In vivo, even though no difference was detected at baseline testing, motor block was significantly prolonged in diabetic as compared with control rats (137 ± 16 vs 86 ± 17 min). CONCLUSIONS: In vitro, local anesthetic neurotoxicity was more pronounced on neurons from diabetic animals, but the survival difference was small. In vivo, subclinical neuropathy leads to substantial prolongation of block duration. We conclude that early diabetic neuropathy increases block duration, whereas the observed increase in toxicity was small.

The role of continuous peripheral nerve blocks.

A continuous peripheral nerve block (cPNB) is provided in the hospital and ambulatory setting. The most common use of CPNBs is in the peri- and postoperative period but different indications have been described like the treatment of chronic pain such as cancer-induced pain, complex regional pain syndrome or phantom limb pain. The documented benefits strongly depend on the analgesia quality and include decreasing baseline/dynamic pain, reducing additional analgesic requirements, decrease of postoperative joint inflammation and inflammatory markers, sleep disturbances and opioid-related side effects, increase of patient satisfaction and ambulation/functioning improvement, an accelerated resumption of passive joint range-of-motion, reducing time until discharge readiness, decrease in blood loss/blood transfusions, potential reduction of the incidence of postsurgical chronic pain and reduction of costs. Evidence deriving from randomized controlled trials suggests that in some situations there are also prolonged benefits of regional anesthesia after catheter removal in addition to the immediate postoperative effects. Unfortunately, there are only few data demonstrating benefits after catheter removal and the evidence of medium- or long-term improvements in health-related quality of life measures is still lacking. This review will give an overview of the advantages and adverse effects of cPNBs.

Continuous interscalene analgesia with ropivacaine 0.2% versus ropivacaine 0.3% after open rotator cuff repair: the effects on postoperative analgesia and motor function.

BACKGROUND: Interscalene analgesia is a recognized technique for the management of postoperative pain after major shoulder surgery. The most effective local anesthetic concentration in this setting is still controversial. In this study, we compared the analgesia and side effects of a continuous infusion of ropivacaine 0.2% and 0.3% administered through an interscalene catheter for the first 48 hours after surgery. METHODS: Eighty consecutive patients scheduled for elective open rotator cuff repair were randomized into 2 groups to receive a continuous infusion of either ropivacaine 0.2% or ropivacaine 0.3% for 48 hours at a rate of 14 mL/h through an interscalene catheter after a preoperative bolus of 40 mL ropivacaine 0.5% in all patients. Pain score (visual analog scale 0-100), intensity of motor block, quality of sleep during the first postoperative night, morphine consumption, side effects, and patient satisfaction were assessed by an anesthesiologist masked to treatment group. RESULTS: Total morphine consumption was significantly reduced in group 0.3% (12 vs 30 mg). Quality of sleep was significantly better in group 0.3% (4% vs 27% of awakening during the first postoperative night). Handgrip strength, visual analog scale scores, and side effects were similar in both groups. CONCLUSION: The use of ropivacaine 0.3% through an interscalene catheter for the first 48 hours after open rotator cuff repair provided a significant reduction of morphine consumption and a better sleep quality for the first postoperative night without increasing the intensity of motor block or side effects.

Subacromial pressures vary with simulated sleep positions.

HYPOTHESIS: Subacromial impingement is one of the underlying factors of rotator cuff pathologies and is linked to increased subacromial pressures. Because humans spend about one-third of their life sleeping, we hypothesized that distinct shoulder positions while sleeping may considerably influence nocturnal subacromial pressures. Consequently, atrophy and rupture can affect tendon healing after rotator cuff repair, thus potentially discrediting the outcome of surgery. MATERIALS AND METHODS: We determined the subacromial pressures acting on the rotator cuff in the 4 most common sleep positions and related these pressures to the mean arterial blood pressure and physical examination findings in 20 healthy volunteers. RESULTS: Subacromial pressures were significantly lower in participants sleeping preferably in a supine position than in participants sleeping in side or prone positions (P < .005). DISCUSSION: As tendon perfusion is crucial for tendon-to-bone healing during postoperative physical therapy after rotator cuff reconstruction and for prevention of additional damage to healthy or already torn cuffs, potential clinical relevance may emerge from the present study. CONCLUSION: Distinct shoulder positions considerably influence subacromial pressures. Our findings may be considered in physiotherapeutic concepts after rotator cuff surgery.

Postoperative pain management following scoliosis surgery.

PURPOSE OF REVIEW: The control of pain after scoliosis surgery is a real challenge for the anesthesiologist. The first reason is that major spine surgery for correction of scoliosis deformation causes severe postoperative pain, and second that patients undergoing these operations are most often children or adolescents who are known to suffer from increased pain sensation compared with adults. RECENT FINDINGS: A multimodal postoperative pain therapy is a well established procedure to control the pain after scoliosis surgery. Recently, prospective, well controlled studies have emphasized the key role of regional techniques in this context. Epidural analgesia has shown significant benefits regarding pain score, bowel recovery and patients' satisfaction. However, different modes of epidural analgesia application have been performed. Several issues including local anaesthetic concentration and infusion rate, duration of application and number of catheters placed will be discussed. The safety concerns associated with this type of analgesia will also be emphasized. SUMMARY: Significant improvements have been made in the control of postoperative pain after correction of scoliosis deformation in recent years. The introduction of epidural analgesia has cleared the way for better analgesic techniques in this surgical context. Properly performed and assessed, the addition of epidural analgesia after scoliosis surgery is a safe and effective form of analgesia and the benefits far outweigh the risks.

Continuous extrapleural infusion of ropivacaine 0.2% after cardiovascular surgery via the lateral thoracotomy approach.

OBJECTIVE: The pharmacokinetics of ropivacaine 0.2% were evaluated during a 48-hour continuous extrapleural infusion with 2 different infusion rates in patients undergoing cardiovascular surgery. The hypotheses that no toxic plasma concentrations of ropivacaine would be reached and that proportionality exists among plasma concentrations and dosage used were tested. DESIGN: A prospective, randomized, nonblinded study. SETTING: The investigation was performed as a single-center study in the Division of Cardiovascular Anesthesia, University Hospital of Zurich, in Switzerland. PARTICIPANTS: Seventeen consenting adults scheduled for elective cardiovascular surgery, with or without extracorporeal bypass, via the lateral thoracotomy approach were enrolled. INTERVENTIONS: For postoperative pain relief, patients were randomly assigned to receive continuous extrapleural infusion of ropivacaine 0.2% at a rate of either 6 or 9 mL/h over 48 hours. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of ropivacaine reached toxic levels (>2.2 mg/L) in 25% of cases. No proportionality of plasma concentrations of ropivacaine existed when the 2 dosing regimens were compared. CONCLUSIONS: Plasma concentrations of ropivacaine, administered at the given dose and rates during continuous extrapleural infusion, are unpredictable and may reach toxic levels in patients undergoing major cardiothoracic surgery.

Effect of selective experimental suprascapular nerve block on abduction and external rotation strength of the shoulder.

The relative contribution to strength of the supraspinatus and infraspinatus to abduction and external rotation is not precisely known. Optimal testing positions for clinical assessment of supraspinatus and infraspinatus function are not precisely defined. We sequentially performed electromyographically controlled, complete nerve blocks of the suprascapular nerve, first at the spinoglenoid notch, to induce complete, isolated infraspinatus palsy. The suprascapular nerve was then blocked at the scapular notch, resulting in complete supraspinatus and infraspinatus palsy in 11 volunteers. Strength of abduction in the scapular plane and of external rotation was measured at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of abduction, by use of a validated, instrumented strength-measuring device. Complete isolated infraspinatus palsy was obtained in 11 volunteers and complete combined supraspinatus and infraspinatus palsy in 9. Infraspinatus palsy alone led to a loss of approximately 70% of external rotation strength and approximately 45% of abduction strength. The degree of loss of strength was not dependent on the angle of abduction. Paralysis of the infraspinatus and the supraspinatus led to a loss of external rotator strength of approximately 80% and a loss of abductor strength of approximately 75%. The loss was again independent of the angle of abduction at which the testing took place. Testing of supraspinatus and infraspinatus strength can be performed at any angle between 30 degrees and 90 degrees without a change in specificity. The contribution of the infraspinatus to abduction strength is great. In the acute situation, the teres minor does not contribute more than 20% of external rotation strength at any degree of abduction.

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 beta1-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.

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 T(0)-T(24) and T(24)-T(48). 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 T(0)-T(24) (26 +/- 10 mg vs 52 +/- 29 mg) and T(24)-T(48) (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.