Continuous peripheral nerve blocks in hospital wards after orthopedic surgery: a multicenter prospective analysis of the quality of postoperative analgesia and complications in 1,416 patients

Effect of TRPV1 combined with lidocaine on cell state and apoptosis of U87-MG glioma cell lines

OBJECTIVE

To study the effects of Transient receptor potential cation channel, subfamily V, member 1 (TRPV1) combined with lidocaine on status and apoptosis of U87-MG glioma cell line, and explore whether local anesthetic produces neurotoxicity by TRPV1.

METHODS

U87-MG cells were divided into control group, gene silencing group, empty vector group and TRPV gene up-regulation group. For cells in each group, flow cytometry was employed to detect the intracellular calcium ion concentration and mitochondrial membrane potential at different time point from cellular perspective. Cell apoptosis of U87-MG was assayed by flow cytometry and MTT from a holistic perspective.

RESULTS

Calcium ion concentration increased along with time. The concentration in TRPV1 gene up-regulation group was significantly higher than those in other groups at each time point (P < 0.05). After adding lidocaine, mitochondrial membrane potential in U87-MG significantly increased (P < 0.05). This increasing trend in TRPV1 gene up-regulation group was more significant than other groups (P < 0.05), while in TRPV1 gene silencing group, the trend significantly decreased (P < 0.05). Flow cytometry result and MTT result both showed that cell apoptosis in each group significantly increased after lidocaine was added (P < 0.05). This increasing trend in TRPV1 gene up-regulation group was more significant than other groups (P < 0.05), while in TRPV1 gene silencing group, the trend significantly decreased (P < 0.05). Moreover, apoptosis was more severe along with the increasing concentration of lidocaine (P < 0.05).

CONCLUSIONS

In this study, it was proved that lidocaine could dose-dependently induce the increase of intracellular calcium ion concentration, mitochondrial membrane potential and apoptosis in U87-MG glioma cell line. The up-regulation of TRPV1 enhanced cytotoxicity of lidocaine, which revealed the correlations between them. Lidocaine might have increased intracellular calcium ion concentration by activating TRPV1 gene and induced apoptosis of U87-GM glioma cell line by up-regulating mitochondrial membrane potential.

Ten Myths and Misconceptions Regarding Pain Management in the ICU

OBJECTIVES

The aim of this article is to expose common myths and misconceptions regarding pain assessment and management in critically ill patients that interfere with effective care. We comprehensively review the literature refuting these myths and misconceptions and describe evidence-based strategies for improving pain management in the ICU.

DATA SOURCES

Current peer-reviewed academic journals, as well as standards and guidelines from professional societies.

STUDY SELECTION

The most current evidence was selected for review based on the highest degree of supportive evidence.

DATA EXTRACTION

Data were obtained via medical search databases, including OvidSP, and the National Library of Medicine's MEDLINE database via PubMed.

DATA SYNTHESIS

After a comprehensive literature review, conclusions were drawn based on the strength of evidence and the most current understanding of pain management practices in ICU.

CONCLUSIONS

Myths and misconceptions regarding management of pain in the ICU are prevalent. Review of current evidence refutes these myths and misconceptions and provides insights and recommendations to ensure best practices.

Pain relief management following proximal femoral fractures: Options, issues and controversies

The majority of proximal femoral fractures occur in the elderly population. Safe and adequate pain relief is an integral part of the overall management of hip fractures. Inherent difficulties in the assessment of pain in elderly need to be taken into account and unique considerations should be made regarding the effective analgesia due to different elderly physiology, and their response to trauma and subsequent surgery. The pain management should start as soon as possible and special emphasis should be paid to contemporary methods of regional anaesthesia whilst a multimodal approach should be adopted in the perioperative period. The present review summarises the contemporary treatment options and controversies pertaining to the management of pain in elderly patients with proximal femoral fractures.

Intracorporeal knotting of a femoral nerve catheter

Peripheral nerve catheters are effective and well-established tools to provide postoperative analgesia to patients undergoing orthopedic surgery. The performance of these techniques is usually considered safe. However, placement of nerve catheters may be associated with a considerable number of side effects and major complications have repeatedly been published. In this work, we report on a patient who underwent total knee replacement with spinal anesthesia and preoperative insertion of femoral and sciatic nerve catheters for postoperative analgesia. During insertion of the femoral catheter, significant resistance was encountered upon retracting the catheter. This occurred due to knotting of the catheter. The catheter had to be removed by operative intervention which has to be considered a major complication. The postoperative course was uneventful. The principles for removal of entrapped peripheral catheters are not well established, may differ from those for neuroaxial catheters, and range from cautious manipulation up to surgical intervention.

Regional anesthesia for an upper extremity amputation for palliative care in a patient with end-stage osteosarcoma complicated by a large anterior mediastinal mass

Tumor progression during end-of-life care can lead to significant pain, which at times may be refractory to routine analgesic techniques. Although regional anesthesia is commonly used for postoperative pain care, there is limited experience with its use during home hospice care. We present a 24-year-old male with end-stage metastatic osteosarcoma who required anesthetic care for a right-sided above-the-elbow amputation. The anesthetic management was complicated by the presence of a large mediastinal mass, limited pulmonary reserve, and severe chronic pain with a high preoperative opioid requirement. Intraoperative anesthesia and postoperative pain management were provided by regional anesthesia using an interscalene catheter. He was discharged home with the interscalene catheter in place with a continuous local anesthetic infusion that allowed weaning of his chronic opioid medications and the provision of effective pain control. The perioperative applications of regional anesthesia in palliative and home hospice care are discussed.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy - preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg^-1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg^-1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg^-1) or NaCl 0.9% (group C; 0.3 mL kg^-1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg^-1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg^-1). Data were compared using Mann-Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

Obesity in regional anesthesia--a risk factor for peripheral catheter-related infections

BACKGROUND

Obesity is believed to increase the risk of surgical site infections and possibly increase the risk of catheter-related infections in regional anesthesia. We, therefore, analyzed the influence of obesity on catheter-related infections defined within a national registry for regional anesthesia.

METHODS

The German Network for Regional Anesthesia database with 25 participating clinical centers was analyzed between 2007 and 2012. Exactly, 28,249 cases (13,239 peripheral nerve and 15,010 neuraxial blocks) of patients ≥ 14 years were grouped in I: underweight (BMI 13.2-18.49 kg/m(2) , n = 597), II: normal weight (BMI 18.5-24.9 kg/m(2) , n = 9272), III: overweight (BMI 25.0-29.9 kg/m(2) , n = 10,632), and IV: obese (BMI 30.0-70.3 kg/m(2) , n = 7,744). The analysis focused on peripheral and neuraxial catheter-related infections. Differences between the groups were tested with non-parametric ANOVA and chi-square (P < 0.05). Binary logistic regression was used to compare obese, overweight, or underweight patients with normal weight patients. Odds ratios (OR and 95% confidence interval) were calculated and adjusted for potential confounders.

RESULTS

Confounders with significant influence on the risk for catheter-related infections were gender, age, ASA score, diabetes, preoperative infection, multiple skin puncture, and prolonged catheter use. The incidence (normal weight: 2.1%, obese: 3.6%; P < 0.001) and the risk of peripheral catheter-related infection was increased in obese compared to normal weight patients [adjusted OR: 1.69 (1.25-2.28); P < 0.001]. In neuraxial sites, the incidence of catheter-related infections differed significantly between normal weight and obese patients (normal weight: 3.2%, obese: 2.3%; P = 0.01), whereas the risk was comparable [adjusted OR: 0.95 (0.71-1.28); P = 0.92].

CONCLUSION

This retrospective cohort study suggests that obesity is an independent risk factor for peripheral, but not neuraxial, catheter-related infections.

Does Regional Anesthesia Improve the Quality of Postoperative Pain Management and the Quality of Recovery in Patients Undergoing Operative Repair of Tibia and Ankle Fractures?

OBJECTIVES

To determine whether the use of peripheral nerve blocks (PNBs) as part of an analgesic protocol for operative repair of tibia and ankle fractures can improve the quality of postoperative pain management and the quality of recovery (QOR).

STUDY DESIGN

Prospective cohort study.

SETTING

Orthopedic trauma service in an academic tertiary care center.

PATIENTS

Ninety-three consecutive patients undergoing operative repair of fractures of the ankle and tibia.

INTERVENTION

Administration of popliteal and saphenous nerve blocks, as part of postoperative analgesia regimen in some patients. Patients were labeled as the regional group or the no-regional group based on whether they received PNBs.

OUTCOMES

Patient satisfaction and the quality of pain management were measured 24 hours after surgery using the Revised American Pain Society Patient Outcome Questionnaire. The QOR was measured at 24 and 48 hours after surgery using the short version of the Quality of Recovery Questionnaire (QOR-9).

RESULTS

Satisfaction with pain management was significantly higher (P = 0.005) in the regional group when compared with the no-regional group. Average pain scores over 24 hours was similar between the 2 groups (P = 0.07). The regional group reported less time spent in severe pain over 24-hour period (40 vs. 50%, P = 0.04) and higher overall perception of pain relief (80 vs. 65%, P = 0.003). Patients receiving regional anesthesia also demonstrated better QOR measured by the QOR-9 at 24 hours (P = 0.04) but not at 48 hours (p = 0.11).

CONCLUSIONS

Patient satisfaction and the quality of postoperative pain management for the first 24 hours were better in patients who received PNBs as part of their postoperative analgesic regimen when compared with patients who received only systemic analgesia.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Regional anesthesia for the trauma patient: improving patient outcomes

Trauma is a significant health problem and a leading cause of death in all age groups. Pain related to trauma is frequently severe, but is often undertreated in the trauma population. Opioids are widely used to treat pain in injured patients but have a broad range of undesirable effects in a multitrauma patient such as neurologic and respiratory impairment and delirium. In contrast, regional analgesia confers excellent site-specific pain relief that is free from major side effects, reduces opioid requirement in trauma patients, and is safe and easy to perform. Specific populations that have shown benefits (including morbidity and mortality advantages) with regional analgesic techniques include those with fractured ribs, femur and hip fractures, and patients undergoing digital replantation. Acute compartment syndrome is a potentially devastating sequela of soft-tissue injury that complicates high-energy injuries such as proximal tibia fractures. The use of regional anesthesia in patients at risk for compartment syndrome is controversial; although the data is sparse, there is no evidence that peripheral nerve blocks delay the diagnosis, and these techniques may in fact facilitate the recognition of pathologic breakthrough pain. The benefits of regional analgesia are likely most influential when it is initiated as early as possible, and the performance of nerve blocks both in the emergency room and in the field has been shown to provide quality pain relief with an excellent safety profile.

Comparison of Periarticular Multimodal Drug Injection and Femoral Nerve Block for Postoperative Pain Management in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

The analgesic efficacy and safety of periarticular multimodal drug injection (PMDI) compared with femoral nerve block (FNB) for postoperative pain management in total knee arthroplasty (TKA) still remains controversial. We therefore conducted a meta-analysis to quantitatively compare PMDI to FNB in TKA. 10 randomized controlled trials (RCTs) with 744 TKAs in 728 patients were included in this study. The meta-analysis showed that single shot FNB may have better pain relief in the early postoperative period compared with single shot PMDI, and continuous PMDI provided postoperative analgesia comparable to that of continuous FNB. No significant difference was seen in regard to the complications between the two groups. However, due to the variation of the included studies, no firm conclusions can be drawn.

Clinical and microbiological evaluation of epidural and regional anaesthesia catheters in injured UK military personnel

INTRODUCTION

The adoption of regional and epidural analgesia in UK military personnel injured in action during Op HERRICK increased from 2008, in line with structural and environmental developments in the UK medical treatment facility. Historically, there have been concerns that invasive analgesic techniques could carry an increased risk of infection, due to the mechanism of injury and the environmental conditions in which the injuries were sustained. Consequently, the epidural and continuous peripheral nerve blockade (CPNB) catheters that were inserted in UK military personnel during a 33-month period of Op HERRICK were clinically and microbiologically examined, after subsequent admission to the University Hospitals Birmingham (UHB) NHS Trust.

METHODS

Data on epidural and CPNB insertions were collected via the specialist pain service at UHB over the study period, including de novo and replacement insertions performed in both Afghanistan and the UK. Patients were regularly reviewed and relevant clinical concerns were documented in patients' case notes as necessary. The anatomical site, duration of placement and the results of microbiological culture of the epidural and CPNB catheter tips were all recorded.

RESULTS

Overall, 236 catheters were assessed, of which 151 catheter tips (64%) were cultured (85 epidural, 66 CPNB). Of these, 48 grew bacteria (34% of cultured epidurals and 29% of cultured CPNB). There was no difference between the colonisation rates of epidurals inserted in Afghanistan and the UK. Only one infection related to a misplaced epidural catheter was confirmed.

CONCLUSIONS

With the exception of the epidural (34%) and proximal sciatic (42%) catheters, these figures, in a military cohort characterised by significant injury scores, are consistent with those reported for civilian surgical patients. The results strongly support the expansion of regional analgesia during Op HERRICK from 2008 onwards. The outcomes suggest a possible translation into civilian major trauma practice.

Chlorhexidine gluconate dressings reduce bacterial colonization rates in epidural and peripheral regional catheters

Introduction. Bacterial colonization of catheter tips is common in regional anesthesia and is a suspected risk factor for infectious complications. This is the first study evaluating the effect of CHG-impregnated dressings on bacterial colonization of regional anesthesia catheters in a routine clinical setting. Methods. In this prospective study, regional anesthesia catheter infection rates were examined in two groups of patients with epidural and peripheral regional catheters. In the first group, regional anesthesia was dressed with a conventional draping. The second group of patients underwent catheter dressing using a CHG-impregnated draping. Removed catheters and the insertion sites were both screened for bacterial colonization. Results. A total of 337 catheters from 308 patients were analysed. There was no significant reduction of local infections in either epidural or peripheral regional anesthesia catheters in both CHG and conventional groups. In the conventional group, 21% of the catheter tips and 41% of the insertion sites showed positive culture results. In the CHG-group, however, only 3% of the catheter tips and 8% of the insertion sites were colonised. Conclusion. CHG dressings significantly reduce bacterial colonization of the tip and the insertion site of epidural and peripheral regional catheters. However, no reductions in rates of local infections were seen.

Femoral nerve infusion after primary total knee arthroplasty: a prospective, double-blind, randomised and placebo-controlled trial

Objectives

Effective analgesia after total knee arthroplasty (TKA) improves patient satisfaction, mobility and expedites discharge. This study assessed whether continuous femoral nerve infusion (CFNI) was superior to a single-shot femoral nerve block in primary TKA surgery completed under subarachnoid blockade including morphine.

Methods

We performed an adequately powered, prospective, randomised, placebo-controlled trial comparing CFNI of 0.125% bupivacaine versus normal saline following a single-shot femoral nerve block and subarachnoid anaesthesia with intrathecal morphine for primary TKA. Patients were randomised to either treatment (CFNI 0 ml to 10 ml/h 0.125% bupivacaine) or placebo (CFNI 0 ml to 10 ml/h normal saline). Both groups received a single-shot femoral nerve block (0.25% 20 ml bupivacaine) prior to placement of femoral nerve catheter and subarachnoid anaesthesia with intrathecal morphine. All patients had a standardised analgesic protocol. The primary end point was post-operative visual analogue scale (VAS) pain score over 72 hours post-surgery. Secondary outcomes were morphine equivalent dose, range of movement, side effects, and length of stay.

Results

A total of 86 patients were recruited. Treatment and placebo groups were comparable. No significant difference was found in VAS pain scores, total morphine equivalent requirements, side effects, range of movement, motor block, or length of hospital stay.

Conclusion

No significant advantage was found for CFNI over a single-shot femoral block and subarachnoid anaesthesia after TKA.

Cite this article: Bone Joint Res 2015;4:11–16.

In vivo study of an extended release bupivacaine formulation following site-directed nerve injection

Site-directed administration of local anesthetic agents incorporated into a slow controlled-release injectable implant prolongs the analgesic effect. However, there are potential neuro- and myotoxic consequences. We evaluated a local anesthetic agent (bupivacaine) loaded into a slow-release biodegradable polymer based on castor oil and poly(lactic acid). The formulation was applied directly to the sciatic nerve area in female imprinting control region mice along with appropriate controls. Local nerve and muscle and systemic toxicity were evaluated over a 3-month period following injection of 0.05, 0.1, and 0.125 mL of the 15% bupivacaine–polymer formulation. Histological samples were prepared and examined; no signs of severe inflammation were observed. Histological inflammation signs were more prominent in both nerves and muscles following application of the largest volumes of the polymer formulation (0.1 and 0.125 mL). Following application of 0.1 mL, 15% bupivacaine–polymer formulation, maximal changes were seen in nerve samples two days and two weeks after injection, with complete resolution one month following injection. Neither blank polymer nor plain bupivacaine 0.5% caused any histological changes. Local nerve and muscle toxicity were affected by duration the of exposure and dose of the local anesthetic agent. However, there were clear indications of time-related healing process 3 months after injection.

Which outcomes related to regional anesthesia are most important for orthopedic surgery patients?

An increasing body of evidence supports the benefits of regional anesthesia in orthopedic surgery. Compared with systemic anesthetic and analgesic approaches, these benefits include more focused and sustained pain control, less systemic side effects, improved patient comfort, earlier mobilization and hospital discharge, lower rates of advanced service requirements, and lower perioperative morbidity and mortality. However, there is discussion about the various outcomes as judged by patients and heath care practitioners. This article recapitulates the literature and presents an overview of endpoints.

Role of regional anesthesia in orthopedic trauma

Regional anesthesia plays a key role in the treatment of patients with orthopedic trauma. Trauma-induced pain can be in multiple locations, severe, and can predispose the patient to other morbidities. Additional complications as a result of the overdependence on opioids as a primary pain therapy that can be minimized or avoided with the use of regional anesthesia. Both neuraxial and peripheral regional techniques in patients with orthopedic trauma should be incorporated into the patient care plan and recognized as an essential therapeutic intervention in the overall treatment of this unique patient population.

[Differences of analgesic efficacy and complication rates between ultrasound and nervestimulator guided peripheral nerve catheters : Database analysis on patient-relevant target parameters]

BACKGROUND

Peripheral nerve catheters (PNC) play an important role in postoperative pain treatment following major extremity surgery. There are several trials reported in the literature which investigated the efficacy and safety of ultrasound (US) and nerve stimulator (NS) guided PNC placement; however, most of these trials were only small and focused mainly on anesthesiologist-related indicators of block success (e.g. block onset time and procedure time) but not primarily on patient-related outcome data including postoperative pain during movement.

AIM

This retrospective analysis compared the analgesic efficacy and safety of US versus NS guided peripheral nerve catheters (PNC) for postoperative pain therapy in a large cohort of patients.

MATERIAL AND METHODS

Data of patients (June 2006-December 2010) treated with US (nus = 368 June 2008-December 2010) and NS (nns = 574, June 2006-May 2008) guided PNC were systematically analyzed. Apart from demographic data, postoperative pain scores [numeric rating scale (NRS): 0-10] on each treatment day, the number of patients with need for additional opioids, cumulative local anesthetic consumption and catheter-related complications were compared.

RESULTS

On the day of surgery patients treated with US-guided PNC reported lower NRS at rest (p = 0.034) and during movement (p < 0.001). Additionally, the number of patients requiring additional opioids on the day of surgery was lower in the US group (absolute difference 12.4 %, p = 0.001). Furthermore, the number of multiple puncture attempts (absolute difference 5.6 %, p < 0.001) and failed catheter placements (absolute difference 3.4 %, p = 0.06) were lower in the US group. There were no patients in both groups with long-lasting neurological impairment.

CONCLUSION

This database analysis demonstrated that patients treated with US-guided PNC reported significantly lower postoperative pain scores and the number of patients requiring additional opioids was significantly lower on the day of surgery. The numbers of multiple punctures and failed catheter placements were reduced in the US group, which might be seen as an advantage of US-guided regional anaesthesia.

Continuous Infragluteal Sciatic Nerve Block for Postoperative Pain Control After Total Ankle Arthroplasty

Continuous peripheral nerve blocks (CPNB) for postoperative pain control are being used more frequently for total ankle arthroplasty. The purpose of this study was to compare the amount of opioid analgesia used in patients with an infragluteal CPNB to that of patients with no CPNB for postoperative pain management after total ankle replacement. A retrospective cohort study was performed on 78 consecutive patients who had a total ankle arthroplasty from October 2006 to June 2013. The primary outcome measure was opioid analgesia use in the first 48 hours postoperatively. The mean postoperative narcotic use in oral morphine equivalents was 64.6 mg in the CPNB group compared to 129.6 mg in the no CPNB group (P < .001). Using an infragluteal CPNB as a means of postoperative pain control in patients undergoing a total ankle replacement is associated with significantly decreased opioid use compared to patients receiving no CPNB.

LEVELS OF EVIDENCE

Therapeutic, Level IV, case series.

Tunneling and suture of thoracic epidural catheters decrease the incidence of catheter dislodgement

BACKGROUND

Dislocation of epidural catheters (EC) is associated with early termination of regional analgesia and rare complications like epidural bleeding. We tested the hypothesis that maximum effort in fixation by tunneling and suture decreases the incidence of catheter dislocation.

METHODS

Patients scheduled for major surgery (n = 121) were prospectively randomized in 2 groups. Thoracic EC were subcutaneously tunneled and sutured (tunneled) or fixed with adhesive tape (taped). The difference of EC length at skin surface level immediately after insertion and before removal was determined and the absolute values were averaged. Postoperative pain was evaluated by numeric rating scale twice daily and EC tips were screened microbiologically after removal.

RESULTS

Both groups did not differ with respect to treatment duration (tunneled: 109 hours ± 46, taped: 97 ± 37) and postoperative pain scores. Tunneling significantly reduced average extent (tunneled: 3 mm ± 7, taped: 10 ± 18) and incidence of clinically relevant EC dislocation (>20 mm, tunneled: 1/60, taped: 9/61). Bacterial contamination showed a tendency to be lower in patients with tunneled catheters (8/59, taped: 14/54, P = 0.08).

CONCLUSION

Thorough fixation of EC by tunneling and suturing decreases the incidence and extent of dislocation and potentially even that of bacterial contamination.

Peripheral nerve blocks for outpatient surgery: evidence-based indications

PURPOSE OF REVIEW

There has been an increasing use of peripheral nerve blocks (PNBs) in ambulatory surgery. Several recent reports have contributed to our understanding of the optimal PNB technique for specific surgical procedures in this setting. In this review, we have summarized the available literature on indications of PNBs for outpatient surgery of the upper extremity.

RECENT FINDINGS

Although many of the recent studies focus on technical aspects of PNBs, few center on evidence-based indications or their utility in the ambulatory setting. The available literature suggests that although multiple techniques have been reported for outpatient shoulder surgery, interscalene brachial plexus block (ISBPB) is currently the most preferred technique. Supraclavicular, infraclavicular, and axillary brachial plexus blocks, however, are all commonly used and effective PNBs for outpatient surgery and analgesia of the arm, forearm, and hand.

SUMMARY

ISBPB is currently the most beneficial PNB for outpatient shoulder surgery. Supraclavicular block functionally can be considered an alternative to the traditional ISBPB; however, additional studies are required before routine use can be recommended. Although the review identified several reports with benefits of one PNB technique over the others, the existing literature suggests that many of these techniques may be interchangeable with regards to procedures of the distal upper extremity. Future studies are indicated to help standardize the techniques, selection, and postoperative management of PNBs for specific surgical indications.

The Cleveland Clinic experience with supraclavicular and popliteal ambulatory nerve catheters

Continuous peripheral nerve blocks (CPNB) are commonly used for intraoperative and postoperative analgesia. Our study aimed at describing our experience with ambulatory peripheral nerve catheters. After Institutional Review Board approval, records for all patients discharged with supraclavicular or popliteal catheters between January 1, 2009 and December 31, 2011 were reviewed. A licensed practitioner provided verbal and written instructions to the patients prior to discharge. Daily follow-up phone calls were conducted. Patients either removed their catheters at home with real-time simultaneous telephone guidance by a member of the Acute Pain Service or had them removed by the surgeon during a regular office visit. The primary outcome of this analysis was the incidence of complications, categorized as pharmacologic, infectious, or other. The secondary outcome measure was the average daily pain score. Our study included a total of 1059 patients with ambulatory catheters (769 supraclavicular, 290 popliteal). The median infusion duration was 5 days for both groups. Forty-two possible complications were identified: 13 infectious, 23 pharmacologic, and 6 labeled as other. Two patients had retained catheters, 2 had catheter leakage, and 2 had shortness of breath. Our study showed that prolonged use of ambulatory catheters for a median period of 5 days did not lead to an increased incidence of complications.

Comparison of Continuous Femoral Nerve Block, Caudal Epidural Block, and Intravenous Patient-controlled Analgesia in Pain Control After Total Hip Arthroplasty: A Prospective Randomized Study

Thirty-six patients who underwent primary unilateral total hip arthroplasty (THA) were randomly allocated to 4 groups with different pain control protocols; continuous femoral nerve block (FNB group), single-shot caudal epidural block with morphine (EB group), intravenous patient-controlled analgesia with fentanyl (IV-PCA group), and systemic administration of nonsteroidal anti-inflammatory drugs (NSAIDs group). Postoperative pain was assessed using the numerical rating scale (NRS) scores and the analgesic effect was compared among the groups. The NRS upon arrival at the recovery room and 6 hours after surgery in the FNB, EB, and IV-PCA groups were significantly lower than that in the NSAIDs group. The amount of additional analgesics requested by the patient was smaller in the FNB, EB, and IV-PCA groups as compared to the NSAIDs group. Regarding the complications related to the analgesia, 5 of the 9 patients in the IV-PCA group complained nausea and vomiting and received antiemetic drugs. Delay in the rehabilitation process due to drowsiness was encountered in 3 patients in this group, while no patient in the FNB and EB groups suffered from delayed rehabilitation. Considering both the analgesic effect and the potential risk of complications, continuous femoral nerve blocks and caudal epidural blocks for are recommended for postoperative pain control after THA procedure.

Special anesthetic consideration for the patient with a fragility fracture

In this article, an overview is presented of perioperative management of the patient with a fragility fracture, including preoperative risk stratification and optimization, anesthesia risks, anesthesia options, and postoperative pain management. Issues of preoperative evaluation that are of concern for the anesthesiologist because of their direct effect on intraoperative care are discussed. A team interdisciplinary approach and good communication between specialties involved in care of elderly surgical patients is important for optimal patient outcomes and to avoid perioperative complications. Cooperation between anesthesiology and medicine is indispensable in reaching a reasonable consensus regarding preoperative evaluation and should occur on a case-by-case basis.

Incidence of failure of continuous peripheral nerve catheters for postoperative analgesia in upper extremity surgery

PURPOSE

To explore the incidence of failure of continuous peripheral nerve blockade (CPNB) after upper extremity operations.

METHODS

Patient data regarding postoperative CPNB were retrospectively obtained from our institution's regional anesthesia database. Documented information on the first postoperative day included pain assessment ratings (numerical verbal pain scale, patient-reported breakthrough pain upon perceived return of sensation, appearance of the catheter site, complications, time of return of sensation, day of return of sensation, residual blockade, patient satisfaction with the block, and whether patient would receive the block again).

RESULTS

A total of 207 patients received CPNB for postoperative analgesia. The failure rate on the first postoperative day for infraclavicular (133 patients) and supraclavicular (58 patients) CPNB was 19% and 26%, respectively. Interscalene CPNB (16 patients) yielded 3 incidences of failure. No significant difference was found between supraclavicular and infraclavicular block techniques. In addition, no significant differences were found between the incidences of CPNB failures with potentially more painful surgeries involving bone compared with potentially less painful soft tissue procedures.

CONCLUSIONS

The CPNB technique used for hand surgery postoperative analgesia was associated with nontrivial failure rates. The potential of CPNB failure and resulting breakthrough pain upon recovery from the primary nerve block is important to help establish patient expectations.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Internet remote control of pump settings for postoperative continuous peripheral nerve blocks: a feasibility study in 59 patients

INTRODUCTION

During continuous peripheral nerve blocks, infusion adjustments are essential for postoperative analgesia without side effects. Beside, physicians and nurse visits related to pump's settings and monitoring are time consuming and costly. We hypothesized that a remote control of pump's settings, by telemedicine transmission, adjusted to patients' feedbacks, is feasible and interesting in optimizing patient's postoperative pain management.

METHODS

Fifty-nine ASA physical status I and II patients were included. Ropivacaine 0.2% was infused during 72 h in CPNB catheters. After returning to the surgical ward, the patient was allowed to answer a 10 indicators questionnaire 3 times a day (8.00 AM, 2.00 PM, 8.00 PM), or unlimited on patient's demand. This information was transmitted from the pump to a server through the Internet. If one indicator was out of the predefined thresholds, the anesthesiologist in charge was immediately informed by texto on his cell phone. The anesthesiologist connected to the website, checked the data from the patient and modified the settings of the pump by remote control according to a written protocol. The changes need a secure access with a password and a confirmation. The number of settings changes, the time to realize the procedure and the adverse events related to the technique were noted. When the catheter was removed, the pump was unassigned to the patient and the data archived.

RESULTS

Thirty sciatic, 24 femoral and 5 interscalene catheters were inserted in 59 patients. Five catheters were accidentally removed before the end of the 72-h period. The median VAS pain values at rest and during movement were respectively at 2 and 3. Sixteen patients complained about numbness promoting 2 (0-3) changes in pump settings; 9 about motor blockade with 1 (0-2) change; 5 about difficulties for physiotherapy with 1 (0-3) change. The mean time of pump settings modification after response to questionnaire or voluntarily patient's alert was 15 ± 2.2 minutes. Early physiotherapy in the surgical ward was totally uneventful in 54 patients. The mean value of satisfaction scale of the patients was 8.4 ± 1.6. No adverse event necessitated a postoperative analgesia technique change.

CONCLUSION

Remote control pump's feedbacks and e-settings for postoperative analgesia using CPNB permitted a real adaptation to patients' needs, complaints and pain VAS values without nurse and physician physical intervention.

Nerve sheath catheter analgesia for forequarter amputation in paediatric oncology patients

In a single centre over two years, four children (7 to 10 years old) with upper limb osteosarcoma underwent chemotherapy followed by forequarter amputation. All patients had preoperative pain and were treated with gabapentin. Nerve sheath catheters were placed in the brachial plexus intraoperatively and left in situ for five to 14 days. After surgery, all patients received local anaesthetic infused via nerve sheath catheters as part of a multimodal analgesia technique. Three of the four patients were successfully treated as outpatients with the nerve sheath catheters in situ. All four children experienced phantom limb pain; however, it did not persist beyond four weeks in any patient.

Regional anesthesia and analgesia in critically ill patients: a systematic review

Regional anesthesia has become invaluable for the treatment of pain during and after a wide range of surgical procedures. However, its benefits in the nonsurgical setting have been less well studied. Regional anesthesia is an appealing modality for critically ill patients, providing focused and sustained pain control with beneficial systemic effect profiles. Indications for regional anesthesia in this patient group are not limited to surgical and postsurgical analgesia but expand to the management of trauma-related issues, medical conditions, and painful procedures at the bedside. Patients in the critical care unit present special challenges to the regional anesthesiologist, including coagulopathies, infections, immunocompromised states, sedation- and ventilation-associated problems, and factors potentially increasing the risk for systemic toxicity. This review is intended to evaluate the role of regional anesthesia in critically ill patients, to discuss potential benefits, and to provide a summary of the published evidence on the subject.

Neurotoxicity induced by bupivacaine via T-type calcium channels in SH-SY5Y cells

There is concern regarding neurotoxicity induced by the use of local anesthetics. A previous study showed that an overload of intracellular calcium is involved in the neurotoxic effect of some anesthetics. T-type calcium channels, which lower the threshold of action potentials, can regulate the influx of calcium ions. We hypothesized that T-type calcium channels are involved in bupivacaine-induced neurotoxicity. In this study, we first investigated the effects of different concentrations of bupivacaine on SH-SY5Y cell viability, and established a cell injury model with 1 mM bupivacaine. The cell viability of SH-SY5Y cells was measured following treatment with 1 mM bupivacaine and/or different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride, an antagonist of T-type calcium channels for 24 h. In addition, we monitored the release of lactate dehydrogenase, cytosolic Ca²⁺ ([Ca2+]_i), cell apoptosis and caspase-3 expression. SH-SY5Y cells pretreated with different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride improved cell viability, reduced lactate dehydrogenase release, inhibited apoptosis, and reduced caspase-3 expression following bupivacaine exposure. However, the protective effect of NNC 55-0396 dihydrochloride plateaued. Overall, our results suggest that T-type calcium channels may be involved in bupivacaine neurotoxicity. However, identification of the specific subtype of T calcium channels involved requires further investigation.

[Regional anesthesia in patients with pre-existing infections or immunosuppression]

Regional anesthesia is the most effective procedure for acute pain therapy. Whether neuraxial and peripheral blocks in patients with pre-existing infectious conditions, immune deficits or other risk factors increase the risk of additional infections is unclear. Analyzing the available literature currently seems to indicate that the incidence of severe infectious complications is generally low. Diabetes, steroid therapy or malignant diseases are apparently present in many cases in which infections associated with regional anesthesia and analgesia have been described. A strict contraindication in patients with pre-existing systemic or local infections seems unjustifiable. A clear and documented risk-benefit ratio in these patients is mandatory.

An in vitro study to evaluate the utility of the "air test" to infer perineural catheter tip location

Injection of air under ultrasound guidance via a perineural catheter after insertion ("air test") has been described as a means to infer placement accuracy, yet this test has never been rigorously evaluated. We tested the hypothesis that the air test predicts accurate catheter location greater than chance and determined the test's sensitivity, specificity, and positive and negative predictive values using a porcine-bovine model and blinded expert in ultrasound-guided regional anesthesia. The air test improved the expert clinician's assessment of catheter tip position compared to chance, but there was no difference when compared to direct visualization of the catheter without air injection.

A new, lateral, continuous, combined, femoral-sciatic nerve approach via a single skin puncture for postoperative analgesia in intramedullary tibial nail insertion

BACKGROUND

The prevalence of anterior knee pain following intramedullary tibial nail insertion is high. Continuous peripheral nerve blockade is an alternative method of pain control to opiods. This case illustrates the use of femoral nerve and sciatic nerve peripheral catheters with an elastomeric infusion pump for major intramedullary nailing surgery.

CASE REPORT

A 36-year-old male with fractures to the left leg bones presented for placement of an intramedullary nail under spinal anesthesia. At the end of the procedure, access to the lateral femoral and sciatic continuous nerve block was achieved by using a stimulator connected to a 110 mm 18G Tuohy needle. Postoperative analgesia was provided with a 40-hour infusion of 0.1% bupivacaine (400 mL) at a rate of 10 mL hour(-1) with an elastomeric pump. Anesthetic dispersion and contrast were investigated. The analog scale remained with scores below 3 during the 40 hours after surgery, and boluses were not necessary.

CONCLUSION

The use of a femoral and sciatic nerve peripheral catheter offered an alternative to conventional pain control. Continuous femoral-sciatic peripheral blockade via a skin puncture with an infusion of 0.1% bupivacaine with elastomeric pumps is a safe and effective procedure in adults.

Kinetics of uptake and washout of lidocaine in rat sciatic nerve in vitro

BACKGROUND

The potency and efficacy of local anesthetics injected clinically for peripheral nerve block depends strongly on the rate of neural drug uptake. However, because diffusion into surrounding tissues and removal by the vascular system are major factors in the overall distribution of lidocaine in vivo, true kinetics of drug/neural tissue interactions must be studied in the absence of those confounding factors.

METHODS

Uptake: Ensheathed or desheathed isolated rat sciatic nerves were exposed to [(14)C]-lidocaine for 0 to 180 minutes and then removed and the lidocaine content of nerve and sheath analyzed. Washout: Isolated nerves were soaked in [(14)C]-lidocaine for 60 minutes and then placed in lidocaine-free solution for 0 to 30 minutes, with samples removed at different times to assess the drug content. Experimental variables included the effects of the ensheathing epineurium, lidocaine concentration, pH, presence of CO(2)-bicarbonate, and incubation duration.

RESULTS

The equilibrium uptake of lidocaine increased with incubation time, concentration, and the fraction of molecules in the nonionized form. The uptake rate was unaffected by drug concentration, but was about halved by the presence of the epineurial sheath, with the washout rate slowed less. Slight alkalinization, from pH 6.8 to pH 7.4, by bicarbonate-CO(2) buffer or a nonbicarbonate buffer, enhanced the neural uptake, and to the same degree. The washout of lidocaine was faster after shorter incubations at high concentrations than when equal amounts of lidocaine were taken up after long incubations at low lidocaine concentrations.

CONCLUSION

Lidocaine enters a nerve by a process other than free diffusion, through an epineurial sheath that is a slight obstacle. Given the rapid entry in vitro compared with the much smaller and transient content measured in vivo, it seems highly unlikely that lidocaine equilibrates with the nerve during a peripheral blockade.