Low-dose ketamine infusion reduces postoperative hydromorphone requirements in opioid-tolerant patients following spinal fusion: A randomised controlled trial.

BACKGROUND: The current opioid epidemic highlights the urgent need for effective adjuvant therapies to complement postoperative opioid analgesia. Intra-operative ketamine infusion has been shown to reduce postoperative opioid consumption and improve pain control in opioid-tolerant patients after spinal fusion surgery. Its efficacy for opioid-naïve patients, however, remains controversial. OBJECTIVE: We hypothesised that low-dose ketamine infusion after major spinal surgery reduces opioid requirements in opioid-tolerant patients, but not in opioid-naïve patients. DESIGN: Randomised placebo-controlled study. SETTING: Single-centre, tertiary care hospital, November 2012 until November 2014. PATIENTS: A total of 129 patients were classified as either opioid-tolerant (daily use of opioid medications during 2 weeks preceding the surgery) or opioid-naïve group, then randomised to receive either ketamine or placebo; there were thus four groups of patients. All patients received intravenous hydromorphone patient-controlled analgesia postoperatively. INTERVENTION: Patients in the ketamine groups received a ketamine infusion (bolus 0.2 mg kg over 30 min followed by 0.12 mg kg h for 24 h). Patients in the placebo groups received 0.9% saline. MAIN OUTCOME MEASURES: The primary outcome was opioid consumption during the first 24 h postoperatively. The secondary outcome was numerical pain scores during the first 24 h and central nervous system side effects. RESULTS: Postoperative hydromorphone consumption was significantly reduced in the opioid-tolerant ketamine group, compared with the opioid-tolerant placebo group [0.007 (95% CI 0.006 to 0.008) versus 0.011 (95% CI 0.010 to 0.011) mg kg h, Bonferroni corrected P < 0.001]. There was no difference in hydromorphone use between the opioid-naïve groups (0.004 and 0.005 mg kg h in the opioid-naïve ketamine and placebo group, respectively, P = 0.118). Pain scores did not differ significantly between the opioid-tolerant ketamine group and the opioid-naïve groups. There was no significant difference in side effects among groups. CONCLUSION: Postoperative low-dose ketamine infusion reduces opioid requirements for the first 24 h following spinal fusion surgery in opioid-tolerant, but not in opioid-naïve patients. TRIAL REGISTRATION: NCT03274453 with clinicaltrials.gov.

The nerve: A fragile balance between physiology and pathophysiology.

Regarding nerves as simple cables and electrical conduits is a gross error that does not allow us to understand the anomalies and disorders observed postoperatively. Instead, nerves should be seen as a living tissue of which physiological regulation is as complex as that of the blood-brain barrier. This review describes the basic structure and functions of this blood-nerve barrier and highlights the mechanisms of its breakdown and the resultant disorders. For clinical practice, it is important to note that the diffusion of molecules from the perineurium or from the blood is very limited, and so the blood-nerve barrier is a major pharmacologic barrier. Any stress upon neural physiological balance, particularly the terminal vascular blood supply, will induce the classic inflammatory cascade. Due to the complexity of the vascular system, nerve ischaemia will occur more quickly when the terminal blood supply is compromised. This blood supply can adapt in a variety of ways but when these possibilities of adaptation are exceeded, tissue ischaemia may be more extensive. Also, even after the initial injury has subsided, inflammation can cause a secondary insult. This could be particularly important in some patients with subclinical neuropathy.

Brachial Plexus Blockade Causes Subclinical Neuropathy: A Prospective Observational Study.

Background: The objective of this study is to determine subclinical changes in hand sensation after brachial plexus blocks used for hand surgery procedures. We used Semmes-Weinstein monofilament testing to detect these changes. We hypothesized that patients undergoing brachial plexus nerve blocks would have postoperative subclinical neuropathy detected by monofilament testing when compared with controls. Methods: In total, 115 hand surgery adult patients were prospectively enrolled in this study. All patients undergoing nerve-related procedures were excluded as well as any patients with preoperative clinically apparent nerve deficits. Eighty-four patients underwent brachial plexus blockade preoperatively, and 31 patients underwent general anesthesia (GA). Semmes-Weinstein monofilament testing of the hand was performed preoperatively on both the operative and nonoperative extremities and postoperatively at a mean of 11 days on both hands. Preoperative and postoperative monofilament testing scores were compared between the block hand and the nonoperated hand of the same patient, as well as between the block hands and the GA-operated hands. Results: There were no recorded clinically relevant neurologic complications in the block group or GA group. A statistically significant decrease in sensation in postoperative testing in the operated block hand compared with the nonoperated hand was noted. When comparing the operated block hand with the operated GA hand, there was a decrease in postoperative sensation in the operated block hand that did not reach statistical significance. Conclusions: Brachial plexus blockade causes subtle subclinical decreases in sensibility at short-term follow-up, without any clinically relevant manifestations.

Minimum local anesthetic volumes for a selective saphenous nerve block: a dose-finding study.

BACKGROUND: Saphenous nerve block contributes to analgesia after knee and lower leg surgery. However, literature reports a wide range of volumes of local anesthetic being used for this block. METHODS: A non-randomized controlled trial in a single university hospital in March 2015. Eighteen healthy volunteers (ASA 1 status, aged 27-43 years; male-to-female ratio 11/7) were needed to determine the minimum local anesthetic volume (MLAV) of mepivacaine 2% using the Dixon up-and-down method to achieve a selective ultrasound-guided saphenous nerve block. The primary endpoint MLAV (ED50 and ED95) for an ultrasound-guided saphenous nerve block were determined. The secondary endpoints were the position of the saphenous nerve, block onset and duration of action, cutaneous spread of the block, and the occurrence of femoral nerve motor block. RESULTS: The measured MLAV dose that was effective in 50% of cases (ED50) for a complete saphenous nerve block was 1.5 mL; the calculated MLAV dose for 95% of cases (ED95) was 1.9 mL. The saphenous nerve was encountered in almost all cases on the anterior/anteromedial aspect of the femoral artery. We found no correlation between local anesthetic volume and the onset or duration of the block. Cutaneous spread of the nerve block was observed on the anteromedial aspect of the lower leg, with considerable individual variation between individuals in the study. No femoral motor block was observed. CONCLUSIONS: For a selective ultrasound-guided saphenous nerve block, the ED95 MLAV of mepivacaine 2% is 1.9 mL.

Spinal Anesthesia Improves Early Pain Levels After Surgical Treatment of Tibial Plateau Fractures.

OBJECTIVES: To determine the effect of spinal anesthesia (SA) on short-term outcomes when compared with general anesthesia in operatively managed tibial plateau fractures. DESIGN: This is an institutional review board-approved retrospective review of prospectively collected data. SETTING: Two level-1 trauma centers. PARTICIPANTS: One hundred twelve patients with a surgically managed tibial plateau fracture were identified within a registry of patients. INTERVENTION: Of these, 29 (25.9%) received SA and 83 (74.1%) received general anesthesia in a nonrandomized fashion. MAIN OUTCOME MEASURES: Short Musculoskeletal Functional Assessment scores, pain levels, knee range of motion, complications, and reoperations. RESULTS: SA was found to be a predictor of lower pain scores at 3 months (odds ratio, 0.32; 95% confidence interval, 0.12-0.95; P = 0.039) but not at 6 months (P = 0.266) or the latest follow-up (P = 0.056). In the multivariate Short Musculoskeletal Functional Assessment model, although anesthesia type was not found to be a statistically significant predictor, other predictors were identified. Anesthesia type was not a predictor of complications or reoperations. In the univariate analysis, SA was associated with an increased knee range of motion at 3 months (121 vs. 111 degrees; P = 0.048) but not at 6 months (P = 0.31) or the latest follow-up (P = 0.053). CONCLUSION: In patients who undergo surgical management of a tibial plateau fracture, the use of SA is associated with decreased pain levels in the early postoperative period; however, there was no effect on functional assessment scores. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Regional versus general anaesthesia for improved cognitive function after procedures other than cardiac surgery or neurosurgery in adult and paediatric patients.

This is the protocol for a review and there is no abstract. The objectives are as follows: The objective of this review is to compare the effects of regional versus general anaesthesia on cognitive function after procedures other than cardiac surgery or neurosurgery in adult and in paediatric patients.

Prilocaine spinal anesthesia for ambulatory surgery: A review of the available studies.

Transient neurologic symptoms (TNS) led to the abandonment of intrathecal lidocaine. We reviewed the published literature for information about the duration of action and side effects of intrathecal prilocaine, which has been recently reintroduced in Europe. Medline and EMBASE databases were searched for the time period from 1966 to 2015. Fourteen prospective and one retrospective study were retrieved. The duration of the surgical block can be adjusted using doses between 40 and 80mg. Hyperbaric prilocaine in doses as low as 10mg can be used for perianal procedures. Four cases of TNS in 486 patients were reported in prospective studies, and none in 5000 cases in a retrospective data set. Spinal prilocaine appears to be safe and reliable for day case anesthesia. However, as chloroprocaine has a shorter duration and a lower risk of TNS and urinary retention, the indications for prilocaine remain to be defined.

Plasma concentrations of ropivacaine following ultrasound-guided or nerve-stimulator-guided femoral nerve block: A prospective randomised study.

OBJECTIVE: Our aim was to establish a plasma concentration curve for ropivacaine following femoral nerve blockade and to ascertain whether the resulting plasma concentrations differ significantly depending on whether neurostimulation (NS) or ultrasound (US) guidance was used. METHODS: Sixteen male and female subjects aged 18 to 80 who were scheduled to undergo unilateral total knee replacement or anterior cruciate ligament reconstruction under general or spinal anaesthesia, and for whom a femoral nerve block was indicated for postoperative analgesia, were enrolled in this prospective, randomised study. Patients were randomised to undergo either US or NS-guidance femoral nerve blocks. All blocks were performed with 20 mL of 5mg/mL ropivacaine. Blood samples were drawn before the nerve block and 20, 30, 40, 50, 60, 70, and 80 minutes after the block. Plasma levels of ropivacaine were analysed by high performance liquid chromatography (HPLC). RESULTS: All blocks were successful and no patient showed signs or symptoms of local anaesthetic toxicity. The plasma concentration of ropivacaine peaked at 30 minutes in both arms. There was no significant difference in peak levels between US and NS-guidance (0.325±0.186 versus 0.356±0.106 µg/mL). Cmax and tmax were very similar between groups (0.364±0.177 versus 0.344±0.127 µg/mL, 33.75±15.06 versus 31.25±13.56 min for US and NS, respectively). CONCLUSION: Plasma concentrations of ropivacaine peak around 30 minutes after a femoral nerve block regardless of the technique used. No significant difference was found between US- and NS-guidance.

Regional analgesia for improvement of long-term functional outcome after elective large joint replacement.

BACKGROUND: Regional analgesia is more effective than conventional analgesia for controlling pain and may facilitate rehabilitation after large joint replacement in the short term. It remains unclear if regional anaesthesia improves functional outcomes after joint replacement beyond three months after surgery. OBJECTIVES: To assess the effects of regional anaesthesia and analgesia on long-term functional outcomes 3, 6 and 12 months after elective major joint (knee, shoulder and hip) replacement surgery. SEARCH METHODS: We performed an electronic search of several databases (CENTRAL, MEDLINE, EMBASE, CINAHL), and handsearched reference lists and conference abstracts. We updated our search in June 2015. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing regional analgesia versus conventional analgesia in patients undergoing total shoulder, hip or knee replacement. We included studies that reported a functional outcome with a follow-up of at least three months after surgery. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We contacted study authors for additional information. MAIN RESULTS: We included six studies with 350 participants followed for at least three months. All of these studies enrolled participants undergoing total knee replacement. Studies were at least partially blinded. Three studies had a high risk of performance bias and one a high risk of attrition bias, but the risk of bias was otherwise unclear or low.Only one study assessed joint function using a global score. Due to heterogeneity in outcome and reporting, we could only pool three out of six RCTs, with range of motion assessed at three months after surgery used as a surrogate for joint function. All studies had a high risk of detection bias. Using the random-effects model, there was no statistically significant difference between the experimental and control groups (mean difference 3.99 degrees, 95% confidence interval (CI) - 2.23 to 10.21; P value = 0.21, 3 studies, 140 participants, very low quality evidence).We did not perform further analyses because immediate adverse effects were not part of the explicit outcomes of any of these typically small studies, and long-term adverse events after regional anaesthesia are rare.None of the included studies elicited or reported long-term adverse effects like persistent nerve damage. AUTHORS' CONCLUSIONS: More high-quality studies are needed to establish the effects of regional analgesia on function after major joint replacement, as well as on the risk of adverse events (falls).

Efficacy and safety of ultrasound-guided distal blocks for analgesia without motor blockade after ambulatory hand surgery.

PURPOSE: To assess the suitability of ultrasound-guided (USG), single-injection distal block(s) for pain management after outpatient hand and wrist bone surgery. METHODS: We conducted a retrospective review of 125 of 198 consecutive ambulatory surgery patients who underwent hand and wrist bone surgery between June 2010 and January 2012. All patients received a USG axillary block using a short-acting local anesthetic (lidocaine) and secondary 1, 2, or 3 (median, radial, or ulnar) USG distal analgesic block(s) using a long-acting local anesthetic (ropivacaine). All patients were contacted by phone on the first postoperative day. All patients received a concomitant prescription of acetaminophen and nonsteroidal anti-inflammatory drugs with opioids as a rescue treatment. Effectiveness and duration of the distal nerve blocks, compliance with analgesic treatment and rescue opioids requirement, opioid-related side effects, prolonged upper limb motor block, quality of sleep on first postoperative night, and patient satisfaction were evaluated. RESULTS: Most distal analgesic blocks were effective (120 of 125; 96%), with an average duration of nearly 12 hours On the first day after surgery, 28 patients (23%) had a numeric verbal scale greater than 3, although 14 of them had taken the rescue opioids. No patient reported prolonged motor blockade or insensate limb. Opioid-related side effects occurred in 23% of patients. CONCLUSIONS: After hand and wrist bone surgery, USG selective distal blocks using a long-acting local anesthetic, combined with oral analgesics, were effective in a large majority of patients. However, pain control was suboptimal for some especially painful procedures such as wrist surgery, trapeziometacarpal arthrodesis, and finger amputation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Consensus of the Orthopedic Anesthesia, Pain, and Rehabilitation Society on the use of peripheral nerve blocks in patients receiving thromboprophylaxis.

Evidence supports the concept that patients undergoing major orthopedic surgery benefit from either thromboprophylaxis or peripheral nerve blocks, especially continuous techniques. A group of anesthesiologists with significant experience in orthopedic anesthesia and peripheral nerve blocks reviewed the literature related to thromboprophylaxis and peripheral nerve blocks and their combination in orthopedics. Major bleeding, including retroperitoneal hematoma, is an established complication of thromboprophylaxis. Major bleeding, including retroperitoneal hematoma, is also an established complication of peripheral nerve blocks. Between 1997 and 2012, only 4 case reports of major bleeding were reported in patients receiving thromboprophylaxis and peripheral nerve blocks. Evidence supports the safety of the combination of thromboprophylaxis and peripheral nerve blocks. This group of experts concluded that currently there is no evidence that the combination of thromboprophylaxis and peripheral nerve block increases the risk of major bleeding compared to either of the treatments alone.

Out-of-hospital traumatic cardiac arrest: an underrecognized source of organ donors.

Whereas the gap between organ supply and demand remains a worldwide concern, resuscitation of out-of-hospital traumatic cardiac arrest (TCA) remains controversial. The aim of this study is to evaluate, in a prehospital medical care system, the number of organs transplanted from victims of out-of-hospital TCA. This is a descriptive study. Victims of TCA are collected in the out-of-hospital cardiac arrest registry of the French North Alpine Emergency Network from 2004 to 2008. In addition to the rates of admission and survival, brain-dead patients and the organ transplanted are described. Among the 540 resuscitated patients with suspected TCA, 79 were admitted to a hospital, 15 were discharged alive from the hospital, and 22 developed brain death. Nine of these became eventually organ donors, with 31 organs transplanted, all functional after 1 year. Out-of-hospital TCA should be resuscitated just as medical CA. With a steady prevalence in our network, 19% of admitted TCA survived to discharge, and 11% became organ donors. It is essential to raise awareness among rescue teams that out-of-hospital TCA are an organ source to consider seriously.

Balloon treatment of posterior shoulder dislocation with reverse Hill-Sachs injury: description of a new technique.

PURPOSE: Posterior shoulder dislocations are rare, and are usually the result of seizures. Anterior defects of the humeral head known as "reverse Hill-Sachs lesions" may increase the risk of recurrent dislocation and are difficult to treat. We developed a percutaneous technique for reduction of the dislocation or reduction of the anterior impaction fracture, using percutaneous balloon dilatation and cement fixation. METHODS: From 2009 to 2012, three patients aged 33, 72 and 75 years were admitted to our institution with a posterior shoulder dislocation showing an anterior "reverse Hill-Sachs" impaction fracture. One case was bilateral (four fractures). Patients were operated upon in the sitting position; the humeral head was stabilised by external fixator pins during balloon inflation. Reduction or filling of the defect was obtained in all cases. All patients were followed up and two patients (three fractures) were examined after one year by an independent observer. The clinical results were assessed using the Constant score and the RAND-36 physical components score. A computed tomography (CT) scan was obtained in all patients before and after the operation and at the latest follow-up. RESULTS: At three months postoperatively, all patients had resumed work or daily life activities with no limitation. The mean Constant score was 71 and RAND-36 score was 85.5. After one year, the mean Constant score was 73 and the RAND-36 score was 86.4 for the two patients who had sufficient follow-up. On the postoperative radiograph and CT scan, sphericity of the humeral head was restored, and the reverse Hill-Sachs impaction was filled or reduced in all cases. There was no recurrent dislocation. CONCLUSION: Based on this small series, we believe that this technique should be added to our current armamentarium for posterior shoulder dislocations showing a deep impaction fracture of the humeral head that are at risk for recurrent dislocation.

Balloon reduction and cement fixation in calcaneal articular fractures: a five-year experience.

PURPOSE: Balloon reduction and cement fixation of displaced articular fractures of the calcaneus have been described elsewhere but support for it lacks clinical evidence. We have been performing the technique since October 2006 and describe here our clinical experience including three to five-year follow up of our first ten cases with no patient lost to follow up. METHODS: From September 2006 to September 2009, ten patients were admitted with a calcaneus fracture, six were female and four male, one case was bilateral (11 fractures). Patients were operated upon in the prone position according to the technique we have described. Reduction was obtained in all cases. Patients were discharged after an average of four days postoperatively and were allowed weight bearing after two to three months. All patients were followed up regularly and were examined by an independent observer at the latest follow up. The clinical results were assessed using the AOFAS ankle score, the Babin score and the RAND-36 physical components score. A CT scan was obtained in all patients before, after the operation and at the latest follow up. RESULTS: After a minimal follow up of 36 months (three to five years), no patient was lost to follow up and none required further surgery. The AOFAS clinical results were rated good or excellent in 81.8 % of cases (nine fractures, eight patients), and the physical component of the RAND-36 was 74.6. One patient only (one fracture) had a bad clinical result and evidence of subtalar arthritis on the CT scan and was offered a subtalar fusion; she refused. All patients had returned to their former professional activities at the same level as before the fracture except one who had retired but had resumed leisure walking. CONCLUSION: Balloon reduction and cement fixation of fresh calcaneal fractures ("balloon calcaneoplasty") appears a safe and effective procedure in a variety of calcaneal fractures with lasting and excellent clinical results. More studies are needed to further refine the indications and the limits of the procedure.

Objective assessment of the immediate postoperative analgesia using pupillary reflex measurement: a prospective and observational study.

BACKGROUND: The evaluation of pain intensity during the immediate postoperative period is a key factor for pain management. However, this evaluation may be difficult in some circumstances. The pupillary dilatation reflex (PDR) has been successfully used to assess the analgesic component of a balanced anesthetic regimen. We hypothesized that PDR could be a reliable index of pain intensity and could guide morphine administration in the immediate postoperative period. METHODS: One hundred patients scheduled to undergo general surgery were included in this prospective observational study. Pain intensity was assessed by using a simple five-item verbal rating scale (VRS). After patients awoke from general anesthesia, those experiencing mild or more severe pain (VRS more than 1) received intravenous morphine titration. Before and after intravenous morphine titration, the PDR induced by a standardized noxious stimulus was measured with a portable pupillometer. A receiver-operating curve was built to estimate the accuracy of PDR in objectively detecting patients requiring morphine titration. Results are given as median (95% CI). RESULTS: On the initial evaluation, a correlation was found between VRS and PDR (ρ = 0.88 [0.83-0.92], P < 0.0001). In the 39 patients that had a VRS more than 1, PDR before and after morphine titration was respectively 35% (31-43) versus 12% (10-14); P < 0.0001. The PDR threshold value corresponding to the highest accuracy to have VRS more than 1 was 23%, with 91% and 94% sensitivity and specificity, respectively. CONCLUSION: In the immediate postoperative period, the PDR is significantly correlated with the VRS. The pupillometer could be a valuable tool to guide morphine administration in the immediate postoperative period.