The minimum effective concentration (MEC90) of bupivacaine for an ultrasound-guided suprainguinal fascia iliaca compartment block for analgesia in knee surgery: a dose-finding study.

Background: In recent years, the suprainguinal fascia iliaca compartment block (SFICB) has become more common in clinical practice. This assessor-blinded dose-finding study aimed to determine the minimum effective concentration (MEC90, MEC95) of bupivacaine for a single-injection SFICB in patients undergoing arthroscopic anterior cruciate ligament repair. Methods: This prospective study was conducted at a tertiary hospital (postoperative recovery room and ward). The SFICB was performed as a postsurgical intervention after spinal anesthesia. Seventy patients were allocated using the biased-coin design up-and-down sequential method. The ultrasound-guided SFICB was performed using different bupivacaine concentrations, and standard multimodal analgesia was administered to all patients. Block success was defined as the absence of pain or presence of only tactile sensation during the pinprick test conducted on the anterior and lateral regions of the mid-thigh six hours postoperatively. Results: According to isotonic regression and bootstrap CIs, the MEC90 value of bupivacaine for a successful SFICB was 0.123% (95% CI: 0.098-0.191) and the MEC95 value was 0.188% (95% CI: 0.113-0.223). Conclusion: Our study showed that the MEC90 and MEC95 values for bupivacaine administered via an SFICB for analgesia were 0.123% and 0.188%, respectively. One advantage of using lower concentrations of bupivacaine is the associated reduction in quadriceps weakness.

Deep posterior gluteal compartment block for regional anaesthesia of the posterior hip: a proof-of-concept pilot study.

Background: Various regional anaesthesia approaches to branches of the anterior lumbar plexus have been proved effective in providing analgesia in hip surgery. However, some patients still experience significant residual posterior hip pain attributed to the posterior nerve supply of the hip. This not only suggests that anterior approaches may not always provide sufficient pain relief, but also that the blocking of major nerves supplying the posterior pericapsular region is needed. Methods: We present an ultrasound-guided technique to block all major nerves supplying the posterior capsule of the hip joint. The optimal target area was determined by ultrasound imaging, cross-sectional digitised anatomy, and cadaver research, and was found in the deep gluteal compartment. Furthermore, this posterior pericapsular deep-gluteal block was evaluated in two patients. Results: The spread of dye in the cadaver was observed deep to the gluteus maximus and in between the quadratus femoris and piriformis muscles, and conformed to the presumed location during the ultrasound procedure. It included all major supplying nerves to the posterior hip capsule, that is the superior gluteal nerve, nerve to quadratus femoris and sciatic nerve. In both patients where this posterior pericapsular deep-gluteal block was applied the pain was substantially reduced (numeric rating scale: 4 to 1 and 7 to 1). Conclusion: We present a successful ultrasound-guided technique targeting the deep gluteal compartment to block all major nerves supplying the hip joint's posterior capsule. This posterior pericapsular deep-gluteal block can be applied as an additional block in hip surgery, with also a possible role in chronic hip pathology.

Serum concentrations of local anesthetics after unilateral interpectoral-pectoserratus plane block in breast cancer surgery: a pharmacokinetic study.

INTRODUCTION: The ultrasound-guided interpectoral-pectoserratus plane block is a fascial plane block for superficial surgery of the anterolateral chest wall. This technique involves injecting a relatively large volume of local anesthetics (typically 30 mL of 0.25%-0.50%, ie, 75-150 mg ropivacaine) underneath the major and minor pectoral muscles of the anterior thoracic wall. There is a potential risk of toxic serum concentrations of local anesthetics due to systemic absorption. METHODS: 22 patients scheduled for elective unilateral breast cancer surgery were included in this study. All surgery was performed with general anesthesia and an ultrasound-guided interpectoral-pectoserratus plane block with 2.5 mg/kg ropivacaine. Ten venous blood samples were collected at 0 (two samples) 10, 20, 30, 45, 60, 90 and 120 min and at 4 hours after performing the block. Free and total ropivacaine levels were measured at each time point. Albumin and alpha-1-acid-glycoprotein were measured to monitor shifts between the free and bound fraction of ropivacaine. RESULTS: Samples of 20 patients were analyzed. The mean dose of ropivacaine was 172.8 (22.5) mg. In 50% of the patients, the potentially toxic threshold of 0.15 µg/mL free ropivacaine concentration was exceeded. Mean peak serum concentration occurred at 20 min postinjection. CONCLUSIONS: This pharmacokinetic study demonstrated that a 2.5 mg/kg ropivacaine interpectoral-pectoserratus plane block may result in exceeding the threshold for local anesthetic systemic toxicity.

Anaesthesia for elite athletes.

BACKGROUND: Sports participation has been growing rapidly since the 1960s. Anaesthesiologists are increasingly confronted with athletes in a peri-operative setting. The right choice of type of anaesthesia technique, pain management of injuries, specific physiologic adaptations of the athlete and knowledge of prohibited substances are eminent for a correct approach of this subpopulation. PURPOSE: This review aims to give an overview of athletes' specific anaesthetic management in peri-operative and postoperative settings and to guide the nonspecialised anaesthetist. METHODS: We comprehensively reviewed the literature, gathered all the information available on, and synthesised it in a narrative way, regarding preoperative evaluation, intraoperative implications and postoperative pain management of the elite athlete undergoing a surgical procedure. RESULTS: An anaesthesiologist should recognise the most common benign ECG findings in athletes like bradycardia, isolated left ventricle hypertrophy on voltage criteria and early repolarisation as normal features in the athlete's heart. Isotonic physiology typically produces four-chamber dilation. In contrast, isometric stress creates high intravascular pressure leading to left ventricular hypertrophy. Pre-operative evaluation should also identify possible consumers of performance-enhancing drugs. Intraoperative points of interest for the anaesthesiologist is mainly avoiding drugs on the prohibited list of the World Anti-Doping Agency (WADA). Postoperative and chronic pain management are still developing fields in this population. The International Olympic Committee (IOC) proposed treating acute pain with a combination of paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), topical analgesics, injectable NSAIDs and local anaesthetics. It may be suggested that chronic pain management in elite athletes could benefit from treatment in specialised multidisciplinary pain clinics. CONCLUSION: This literature review aims to serve as a guide for the anaesthesiologist taking care of the elite athlete.

Supra-inguinal injection for fascia iliaca compartment block results in more consistent spread towards the lumbar plexus than an infra-inguinal injection: a volunteer study.

BACKGROUND AND OBJECTIVES: Lumbar plexus block has been used to provide postoperative analgesia after lower limb surgery. The fascia iliaca compartment block (FICB) has been proposed as an anterior approach of the lumbar plexus targeting the femoral, obturator and lateral femoral cutaneous nerve. However, both radiological and clinical evidence demonstrated that an infra-inguinal approach to the fascia iliaca compartment does not reliably block the three target nerves.We hypothesized that a supra-inguinal approach of the fascia iliaca compartment results in a more consistent block of the three target nerves than an infra-inguinal approach. METHODS: We performed a randomized controlled, double-blind trial in 10 healthy volunteers. Both an infra-inguinal FICB (I-FICB) and a supra-inguinal FICB (S-FICB) were performed on the left or the right side in each volunteer. Forty milliliters of lidocaine 0.5% was injected with each approach. Sensory and motor block and spread of local anesthetics (LA) on MRI were assessed. RESULTS: After an S-FICB, 80% of the volunteers had a complete sensory block of the medial, anterior and lateral region of the thigh, compared with 30% after an I-FICB (p=0.035). There was an insignificant effect on motor function with both approaches. After an S-FICB, in 8 out of 10 volunteers there was spread of LA in the expected anatomic location of the obturator nerve on MRI compared with 1 out of 10 volunteers after an I-FICB (p=0.0017). The cranial spread of LA after an S-FICB on MRI was higher than after an I-FICB (p=0.007), whereas there was a more caudal spread of LA on MRI after an I-FICB than after an S-FICB (p=0.005). CONCLUSIONS: An S-FICB produces a more complete sensory block of the medial, anterior and lateral region of the thigh, compared with an I-FICB. Our study demonstrates that an S-FICB with 40 mL of LA more reliably spreads LA to the anatomical location of the three target nerves of the lumbar plexus on MRI than an I-FICB. An S-FICB also leads to a more consistent spread in a cranial direction under the fascia iliaca and around the psoas muscle. CLINICAL TRIAL REGISTRATION: This work was registered with the European clinical trial registry: Identifier Eudra CT 2015-004607-24.

The effect of the volume of supra-inguinal injected solution on the spread of the injectate under the fascia iliaca: a preliminary study.

The fascia iliaca compartment is the compartment confined by the fascia iliaca (FI) and a muscular layer formed by the iliac- and psoas muscle. This compartment creates a virtual tunnel that contains the femoral nerve (FN), the obturator nerve (ON), and the lateral femoral cutaneous nerve (LFCN) of the lumbar plexus. In this pilot study, we aimed to determine the suggested volume needed to reach the three target nerves of the lumbar plexus (FN, ON, and LFCN) with a single-injection ultrasound-guided supra-inguinal fascia iliaca compartment (S-FICB). A computer tomography (CT scan)-guided step-up/step-down sequence was used to determine the suggested injection volume to target all three nerves. Subsequently, an anatomist blinded for the injected volume and CT findings, dissected the cadavers, and evaluated the spread of dye underneath the fascia iliaca. In total, seven pelvic areas of four cadavers were evaluated on CT scan and dissected. Distribution of dye underneath the FI in relation to the FN, ON, and the LFCN was recorded in all dissected cadavers. Combining CT and dissection findings, the suggested volume to reach the FN, ON, and LFCN with an S-FICB was 40 mL.

Opening Injection Pressure Is Higher in Intraneural Compared With Perineural Injections During Simulated Nerve Blocks of the Lower Limb in Fresh Human Cadavers.

BACKGROUND AND OBJECTIVES: Needle-induced nerve trauma and intraneural injection can lead to neurologic injury during peripheral nerve blocks. In this study, we assessed the utility of opening injection pressure (OIP), time to OIP, and rate of rise to OIP in detecting needle-nerve contact and intraneural injection. METHODS: Five common ultrasound-guided blocks of the femoral, saphenous, subgluteal sciatic, tibial, and common peroneal nerves were simulated in 10 fresh cadavers. Opening injection pressure was defined as peak psi in the 60-second interval during which the injection is initiated. Pressure-time curves were constructed separately for intraneural and perineural injections for each of the 5 nerves studied. RESULTS: Opening injection pressure was higher for intraneural than for perineural injections (P < 0.001), ranging from 21.5 psi (1111.9 mm Hg) to 25.8 psi (1334.2 mm Hg) for intraneural injections and from 3.8 psi (196.5 mm Hg) to 6.1 psi (315.5 mm Hg) for perineural injections. Time to OIP tended to be shorter for intraneural than for perineural injections, particularly for the subgluteal sciatic, tibial, and common peroneal nerves. Curves of intraneural injections had steep slopes with high peaks; curves of perineural injections had low slopes followed by plateaus. Rise to OIP was greater for intraneural than for perineural injections. CONCLUSIONS: In our fresh human cadaver model, OIP detected intraneural needle placement. Monitoring of OIP could be useful in detecting and/or preventing intraneural injection during nerve blocks in the clinical setting.

A Longitudinal Supra-Inguinal Fascia Iliaca Compartment Block Reduces Morphine Consumption After Total Hip Arthroplasty.

BACKGROUND AND OBJECTIVES: The role of a fascia iliaca compartment block (FICB) for postoperative analgesia after total hip arthroplasty (THA) remains questionable. High-dose local anesthetics and a proximal injection site may be essential for successful analgesia. High-dose local anesthetics may pose a risk for local anesthetic systemic toxicity. We hypothesized that a high-dose longitudinal supra-inguinal FICB is safe and decreases postoperative morphine consumption after anterior approach THA. METHODS: We conducted a prospective, double blind, randomized controlled trial. Patients scheduled for THA were randomized to group FICB (longitudinal supra-inguinal FICB with 40-mL ropivacaine 0.5%) or group C (control, no block). Standard hypothesis tests (t test or Mann-Whitney U test, χ test) were performed to analyze baseline characteristics and outcome parameters. The primary end point of the study was total morphine (mg) consumption at 24 hours postoperatively. Serial total and free ropivacaine serum levels were determined in 10 patients. RESULTS: After obtaining ethical committee approval and written informed consent, 88 patients were included. Mean (SD) morphine consumption at 24 hours postoperatively was reduced in group FICB compared to group C: 10.25 (1.64) mg versus 19.0 (2.4) mg (P = 0.004). Using a mean dose of 2.6-mg/kg ropivacaine (range, 2-3.4 mg/kg), none of the patients had total or free ropivacaine levels above the maximum tolerated serum concentration. CONCLUSIONS: We conclude that a high-dose longitudinal supra-inguinal FICB reduces postoperative morphine requirements after anterior approach THA.Clinical Trials Registry: EU Clinical Trials Register. www.clinicaltrialsregister.eu #2014-002122-12.

A double-blind randomized controlled trial comparing dexamethasone and clonidine as adjuvants to a ropivacaine sciatic popliteal block for foot surgery.

BACKGROUND AND AIMS: A popliteal block is effective in managing postoperative pain for foot surgery, but since the duration of analgesia is limited following a single-shot popliteal fossa block technique, methods to prolong effective postoperative analgesia are mandatory. The aim of this study was to assess the effect of adjuvants to ropivacaine on the duration of sensory and motor block. METHODS: In this double-blind randomized placebo-controlled study, we evaluated the analgesic effect of clonidine or dexamethasone (DXM) when added to ropivacaine for hallux valgus surgery. After obtaining institutional ethics research board approval and written informed consent, a total of 72 patients were randomly allocated. Fifty-seven of these patients were statistically analyzed. All patients received an ultrasound-guided single-shot popliteal fossa block with 30 mL of ropivacaine 0.75%, supplemented with saline, clonidine 100 µg, or DXM 5 mg. The primary end point was time to first pain sensation. Secondary end points were time to complete sensory and motor block regression. RESULTS: Compared to saline, duration to first pain sensation was prolonged by 9 hours (mean ± standard deviation: 31±9 hours) (42%) in the DXM group (P=0.024) and by 6 hours (28±10 hours) (27%) in the clonidine group (P=0.024). Compared to saline, DXM prolonged both complete sensory and motor blockade by 12 hours (25±7 hours) (46%) and 13 hours (36±6 hours) (55%), respectively, while clonidine prolonged complete sensory and motor blockade by 7 hours (30±7 hours) (27%) and 2 hours (22±5 hours) (10%), respectively. DXM prolonged sensory block regression time by 6 hours (21±7 hours) (41%) and clonidine by 2 hours (17±6 hours) (13%) compared to the control group (P=0.006). Similarly, DXM prolonged motor block regression by 7 hours (25±7 hours) (46%) and clonidine by 4 hours (21±4 hours) (19%) (P<0.0001). CONCLUSION: Addition of DXM and clonidine to ropivacaine significantly prolonged the duration of postoperative sensory and motor block.

A comparison in adolescents of composite auditory evoked potential index and bispectral index during propofol-remifentanil anesthesia for scoliosis surgery with intraoperative wake-up test.

BACKGROUND: The electroencephalogram-derived Bispectral Index (BIS), and the composite A-line ARX index (cAAI), derived from the electroencephalogram and auditory evoked potentials, have been promoted as anesthesia depth monitors. Using an intraoperative wake-up test, we compared the performance of both indices in distinguishing different hypnotic states, as evaluated by the University of Michigan Sedation Scale, in children and adolescents during propofol-remifentanil anesthesia for scoliosis surgery. Postoperative explicit recall was also evaluated. METHODS: Twenty patients (aged 10-20 yr) were enrolled. Prediction probabilities were calculated for induction, wake-up test, and emergence. BIS and cAAI were compared at the start of the wake-up test, at purposeful movement to command, and after the patient was reanesthetized. During the wake-up test, patients were instructed to remember a color, and were then interviewed for explicit recall. RESULTS: Prediction probabilities of BIS and cAAI for induction were 0.82 and 0.63 (P < 0.001), for the wake-up test, 0.78 and 0.79 (P < 0.001), and 0.74 and 0.78 for emergence (P < 0.001). During the wake-up test, a significant increase in mean BIS and cAAI (P < 0.05) was demonstrated at purposeful movement, followed by a significant decline after reintroduction of anesthesia. CONCLUSIONS: During induction, BIS performed better than cAAI. Although cAAI was statistically a better discriminator for the level of consciousness during the wake-up test and emergence, these differences do not appear to be clinically meaningful. Both indices increased during the wake-up test, indicating a higher level of consciousness. No explicit recall was demonstrated.