Super-refractory status epilepticus, rhabdomyolysis, central hyperthermia and cardiomyopathy attributable to spinal anesthesia: a case report and review of literature.

BACKGROUND: There are only six past reports of super-refractory status epilepticus induced by spinal anesthesia. None of those patients have died. Only < 15 mg of bupivacaine was administered to all six of them and to our case. Pathophysiology ensuing such cases remains unclear. CASE PRESENTATION: A 27 year old gravida 2, para 1, mother at 37 weeks of gestation came to the operating theater for an elective cesarean section. She had no significant medical history other than controlled hypothyroidism and one episode of food allergy. Her current pregnancy was uneventful. Her American Society of Anesthesiologists (ASA) grade was 2. She underwent spinal anesthesia and adequate anesthesia was achieved. After 5-7 min she developed a progressive myoclonus. After delivery of a healthy baby, she developed generalized tonic clonic seizures that continued despite the induction of general anesthesia. She had rhabdomyolysis, one brief cardiac arrest and resuscitation, followed by stress cardiomyopathy and central hyperthermia. She died on day four. There were no significant macroscopic or histopathological changes in her brain that explain her super refractory status epilepticus. Heavy bupivacaine samples of the same batch used for this patient were analyzed by two specialized laboratories. National Medicines Quality Assurance Laboratory of Sri Lanka reported that samples failed to confirm United States Pharmacopeia (USP) dextrose specifications and passed other tests. Subsequently, Therapeutic Goods Administration of Australia reported that the drug passed all standard USP quality tests applied to it. Nonetheless, they have detected an unidentified impurity in the medicine. CONCLUSIONS: After reviewing relevant literature, we believe that direct neurotoxicity by bupivacaine is the most probable cause of super-refractory status epilepticus. Super-refractory status epilepticus would have led to her other complications and death. We discuss probable patient factors that would have made her susceptible to neurotoxicity. The impurity in the drug detected by one laboratory also would have contributed to her status epilepticus. We propose several possible mechanisms that would have led to status epilepticus and her death. We discuss the factors that shall guide investigators on future such cases. We suggest ways to minimize similar future incidents. This is an idiosyncratic reaction as well.

Lipid emulsion treatment for local anesthetic systemic toxicity in pediatric patients: A systematic review.

BACKGROUND: Local anesthetic systemic toxicity (LAST) is rare, but fatal; the current widely used treatment is lipid emulsion (LE). The goal of this study was to analyze and review case reports on LE treatment for LAST in pediatric patients. METHODS: We performed a systematic review using case reports on LE treatment for LAST in pediatric patients, searching PubMed and Scopus databases to March 2023 using the following keywords: ("local anesthetic toxicity" OR "local anesthetic systemic toxicity" OR LAST") AND ("newborn" OR "infant" OR "child" OR "children" OR "adolescent" OR "pediatric") AND ("lipid emulsion" OR "Intralipid"). RESULTS: Our search yielded 21 cases, revealing that nearly 43% patients with LAST were less than 1 year old, and most cases were caused by bupivacaine (approximately 67% cases). "Inadvertent intravascular injection" by anesthesiologists and "overdose of local anesthetics" mainly by surgeons were responsible for 52% and 24% cases of LAST, respectively. LAST occurred in the awake state (52%) and under general anesthesia (48%), mainly causing seizures and arrhythmia, respectively. Approximately 55% of patients received LE treatment in <10 minutes after LAST, mainly improving cardiovascular symptoms. A 20% LE (1.5 mL/kg) dose followed by 0.25 mL/kg/minutes dose was frequently used. LE and anticonvulsants were mainly used in the awake state, whereas LE with or without vasopressors was mainly used under general anesthesia. LE treatment led to full recovery from LAST in 20 cases; however, 1 patient died due to underlying disease. CONCLUSION: Consequently, our findings reveal that LE is effective in treating pediatric LAST.

Local Anesthetic Systemic Toxicity During Transversus Abdominis Plane Block With Liposomal Bupivacaine.

Local anesthetic systemic toxicity (LAST) is a rare but potentially fatal outcome associated with local anesthetic administration. Liposomal bupivacaine (LB; EXPAREL®) is a widely used local anesthetic with extended-release and liposomal formulation that carries an improved cardiac and central nervous system safety profile. However, there is limited data regarding LAST associated with liposomal bupivacaine. Here is described a case of local anesthetic systemic toxicity in a 68-year-old male who presented with obstructing sigmoid adenocarcinoma and underwent open sigmoidectomy with end descending colostomy. The operation was complicated by LAST following transversus abdominis plane block injection with liposomal bupivacaine resulting in cardiac arrest. Return of spontaneous circulation was achieved following advanced cardiac life support and infusion of 20% I.V. fat emulsion. Given the widespread use of local anesthetics, providers must be aware of the pathophysiology, diagnosis, and immediate treatment of LAST.

Local anaesthetic systemic toxicity complicating intraoperative intercostal nerve blocks: What do clinicians need to know to prevent similar occurrence?

Local anaesthetic systemic toxicity is a life-threatening adverse event that may occur after administration of local anaesthetics through a variety of routes. Local anaesthetic systemic toxicity is always a potential complication and may occur with all local anaesthetics and in any route of administration. Local anaesthetic systemic toxicity primarily affects the central nervous system and the cardiovascular system and may be fatal. The following is a case of local anaesthetic systemic toxicity complicating surgeon-performed intraoperative intercostal nerve blocks at multiple levels, with a mixture of liposomal bupivacaine and bupivacaine hydrochloride in a patient who underwent video-assisted segmental lung resection for lung cancer under general anaesthesia. Local anaesthetic systemic toxicity presented with seizures and hypotension. The patient was successfully managed and fully recovered. This case illustrates the importance of awareness regarding the prevention, diagnosis and treatment of local anaesthetic systemic toxicity among medical professionals who administer local anaesthetics.

TRANSCARUNCULAR DOUBLE INJECTION TECHNIQUE FOR PERIBULBAR ANESTHESIA IN VITREORETINAL SURGERY.

PURPOSE: Local anesthesia is commonly adopted in vitreoretinal surgery to reach painless and akinesia surgical condition. Currently, peribulbar anesthesia (PBA) and subtenon injection (STN) are the most widely used methods. We propose a transcaruncular double injection peribulbar technique (TRS) and aim to compare it with both standard PBA and STN injections. METHODS: A total of 105 patients underwent TRS, PBA, or STN. A numerical rating scale was used to assess preoperative, postoperative, and intraoperative pain. Best akinesia score and onset and duration of akinesia were evaluated by two independent graders. The need for supplementary injection was also registered. RESULTS: TRS group was characterized by a lower intraoperative numerical rating scale variation and absolute numerical rating scale score both at the beginning of surgery ( P 0.046), after 30 minutes ( P 0.032), and at the end of surgery ( P 0.002) compared with the other groups. The TRS group also showed better akinesia score ( P 0.004), fastest onset ( P 0.002), and longer duration ( P 0.042) compared with both PBA and STN. No injection-related complications were reported in the three groups. CONCLUSION: The newly proposed transcaruncular PBA provided superior pain control and akinesia level with no additional adverse events.

Electroacupuncture alleviates multifidus muscle injury by modulating mitochondrial function and Ca2+ uptake.

Multifidus muscles maintain the stability of the lumbar spine and play a crucial role in the pathogenesis of nonspecific lower back pain. Previous studies have shown that electroacupuncture (EA) can relieve the symptoms of low back pain and reduce injury to the lumbar multifidus muscles. In this study, a rat model of lumbar multifidus muscle injury was established by 0.05% bupivacaine injection and subsequently treated with EA at bilateral "Weizhong" (BL40) acupoints. Disruption of the function and structure of multifidus muscles, increased cytosolic Ca2+ in multifidus myocytes, and reduced mitochondrial fission and ATP production were observed in the model group. Additionally, increased expression of the mitochondrial calcium uniporter (MCU) promoted mitochondrial reuptake of Ca2+ , reversing the excessive increase in cytoplasmic Ca2+ . However, the excessive increase in MCU not only aggravated the increased cytoplasmic Ca2+ but also decreased the expression of the mitochondrial division proteins dynamin-related protein 1 (Drp1) and mitochondrial fission factor (MFF). EA inhibited the overexpression of MCU, promoted mitochondrial reuptake of Ca2+ , and reversed cytosolic Ca2+ overload. Furthermore, EA regulated the expression of the mitochondrial fission proteins Drp1 and MFF and promoted the production of ATP, helping the recovery of mitochondrial function after multifidus injury. Therefore, EA can protect against bupivacaine-induced mitochondrial dysfunction, possibly by attenuating MCU overexpression in the inner mitochondrial membrane and reducing Ca2+ overloading in muscle cells, thereby protecting mitochondrial function and maintaining the normal energy demand of muscle cells.

[Systemic toxicity secondary to local anesthetic infiltration]. / Toxicidad sistémica secundaria a infiltración con anestésico local.

INTRODUCTION: Local anaesthetics (LA) are drugs that are widely used in anaesthetic procedures because of their favourable risk/benefit profile compared to general anaesthetics. Yet, these drugs also have some adverse effects. CASE REPORT: We report the case of a 44-year-old man with no neurological history who presented systemic toxicity due to LA after instillation of intrathecal bupivacaine for hip arthroplasty surgery. CONCLUSIONS: Systemic toxicity caused by LA can give rise to neurological symptoms that may or may not be associated with haemodynamic instability. Neurological symptoms usually occur early on and should alert to the possible occurrence of further life-threatening haemodynamic events. Being aware of the existence of these toxicities and their clinical management is essential to improve the evolution and prognosis of this potentially fatal condition.

TITLE: Toxicidad sistémica secundaria a infiltración con anestésico local.Introducción. Los anestésicos locales (AL) son fármacos ampliamente utilizados para procedimientos anestésicos por su perfil riesgo/beneficio favorable respecto a los anestésicos generales. No obstante, estos fármacos no están exentos de efectos adversos. Caso clínico. Hombre de 44 años sin antecedentes neurológicos que presenta un cuadro de toxicidad sistémica por AL tras la instilación de bupivacaína intratecal para ser intervenido de artroplastia de cadera. Conclusiones. Los cuadros de toxicidad sistémica por AL pueden producir sintomatología neurológica asociada o no a inestabilidad hemodinámica. Habitualmente, los síntomas neurológicos ocurren de forma precoz y deben alertar sobre la posible ocurrencia de eventos hemodinámicos ulteriores que pueden comprometer la vida del paciente. Conocer la existencia y el manejo clínico de estos cuadros de toxicidad resulta fundamental para mejorar la evolución y el pronóstico de este cuadro potencialmente mortal.

Brown Syndrome from Local Anesthesia for Inferior Orbital Fat Decompression.

BACKGROUND Vertical diplopia that follows local anesthesia is usually due to inferior rectus muscle fibrosis. Here, we report a rare case of acquired Brown syndrome following local anesthesia. CASE REPORT A 36-year-old woman underwent right inferior orbital fat decompression under local anesthesia. On the first postoperative day, she developed vertical diplopia. She had left hypertropia, which increased on left gaze, with limitation of elevation of the right eye on attempted adduction. Forced duction test of the right eye revealed resistance on elevation in adduction. Magnetic resonance imaging showed signal alteration, thickening, and irregularity involving the right superior oblique tendon and trochlea region. The diagnosis of iatrogenic Brown syndrome was made. Then, a single dose of 10 mg triamcinolone injection was given near the intratrochlear region. On follow-up, complete resolution of diplopia on primary gaze occurred 12 weeks after the incident. CONCLUSIONS The reported case highlights that local anesthesia carries a risk of Brown syndrome. We believe bupivacaine-induced superior oblique hypertrophy is the underlying mechanism. The patient showed excellent outcome after medical management, with no surgical intervention required after 3 months of follow-up.

Transient lower cranial nerve palsies following spinal anesthesia with bupivacaine-fentanyl combination for transurethral resection of the prostate.

Spinal anesthesia is a widely used regional anesthesia for many infra-umbilical surgical procedures with proven efficacy and safety. However, although rare, some neurologic complications can occur with potentially life threatening consequences. Among them, lower cranial nerve palsies have been rarely reported in the literature. We report such a case in a 75-year-old man with transient dysphagia, dysphonia and spinal accessory nerve palsy occurring four days after spinal anesthesia for transurethral resection of the prostate. His symptoms completely resolved spontaneously within 2 weeks. The possibility of lower cranial nerve palsies should be added to the potential complications during or following spinal anesthesia with bupivacaine-fentanyl combination. Although transitional, this complication may occur few days after the procedure and need to be promptly recognized, carefully evaluated and treated by conservative measures.

Local Anesthetic Facelift.

A thorough medical history is critical in patient selection for local anesthesia facelifting. Patients with no prior issues with dental procedures and no history of significant anxiety are better candidates. Simplifying local anesthesia mixtures and using dilute concentrations will minimize dosing errors and decrease risk of local anesthesia toxicity. Oral anxiolytics can be used with caution to minimize patient anxiety. Pulse oximetry, telemetry, and blood pressure monitoring should be performed with any addition of oral or IV sedation/anxiolytic. The short-scar anterior facelift is ideal for local anesthesia due to the limited deep-plane dissection and shorter procedure duration.

Stellate ganglion block and cardiac sympathetic denervation in patients with inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy. OBJECTIVE: To study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST. METHODS: Twelve consecutive patients who had drug-refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD. RESULTS: The mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement. CONCLUSION: SG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.

Incidence and impact factors of intraoperative loss of light perception under sub-Tenon's anesthesia in patients with macular diseases.

PURPOSE: To investigate the incidence and impact factors of intraoperative loss of light perception (LP) under sub-Tenon's anesthesia in patients with macular diseases. METHODS: Eighty-five consecutive patients received standard phacoemulsification combined pars plana vitrectomy (PPV) under sub-Tenon's anesthesia. At several checkpoints during the surgery (the end of phacoemulsification, the end of vitrectomy, and the end of surgery), participants were interviewed about whether they had LP or not after removing the influence of contralateral eye and the photo-bleaching effect. In patients treated with retinal photocoagulation, visual experience on laser flashes was evaluated. RESULTS: Under routine draping, no patients reported loss of LP at all the checkpoints. When the contralateral eye was tightly covered, the rates of LP loss were 84.7%, 97.6%, and 87.1% at the end of phacoemulsification, the end of vitrectomy, and the end of surgery, respectively. When the photo-bleaching effect was also removed, the rates of LP loss were 61.2%, 82.4%, and 56.5% at each checkpoint, respectively, and there were 87.1% (74/85) of patients reporting visual loss in at least one checkpoint. In addition, 76.9% (50/65) of patients could not feel laser flashes during retinal photocoagulation. CONCLUSION: Intraoperative loss of LP under sub-Tenon's anesthesia was a relatively common and reversible event. The conduction block of optic nerve by anesthetic mainly contributed to the visual loss during surgery. Photo-bleaching effect also has some effect on the LP evaluation. Surgeons need to inform and counsel the patients about the intraoperative loss of LP, to prevent any sudden panic attacks in them.

Onset Time of Local Anesthesia After Single Injection in Toe Nerve Blocks: A Randomized Double-Blind Trial.

PURPOSE: The study was conducted to investigate the onset time and safety profile of four different local anesthetic solutions. DESIGN: Randomized controlled clinical trial study. METHODS: One hundred twelve healthy volunteers were assigned to receive digital block on their second toe. Individuals were randomly assigned to one of the following groups: lidocaine 2%, lidocaine 2% with epinephrine, bupivacaine 0.5%, or bupivacaine 0.5% with epinephrine. Onset time was measured until detecting the absence of pinprick sensation. Oxygen saturation was measured in the infiltrated toe up to 60 minutes. FINDINGS: The subjects in the groups of anesthetics with epinephrine had a significantly lower mean onset time. There were no significant differences regarding oxygen saturation between the groups and no adverse effects were recorded. CONCLUSIONS: The use of anesthetics with epinephrine can be an effective form of local anesthetic for digital blocks when a rapid onset of action, prolonged duration of anesthesia, and vasoconstrictive action are required.

Incidence of adverse events attributable to bupivacaine liposome injectable suspension or plain bupivacaine for postoperative pain in pediatric surgical patients: A retrospective matched cohort analysis.

BACKGROUND: Surgical wound infiltration with local anesthetics is common as part of multimodal analgesia and enhanced recovery pathways in pediatric surgical patients. Liposomal bupivacaine can provide up to 92 hours of pain relief, and was approved by the U.S Food and Drug Administration for local infiltration in adults. It is also commonly used by pediatric surgeons, but its safety profile in this age group has not been described. AIMS: The aim of this study was to describe the incidence of local anesthetic systemic toxicity syndrome in pediatric surgical patients receiving liposomal bupivacaine compared to plain bupivacaine for surgical wound infiltration. METHODS: We conducted a retrospective, single center, assessor blinded cohort study of pediatric surgical inpatients having open or laparoscopic surgery in the Cleveland Clinic between 2013 and 2017 and receiving wound infiltration with local anesthetics. We compared the incidence of local anesthetic systemic toxicity among those who received any dose of liposomal bupivacaine and those who received plain bupivacaine. Groups were matched 1:2 according to procedure type, age, and physical status score. Local anesthetic systemic toxicity was primarily defined as at least two signs or symptoms possibly related to anesthetic toxicity, as judged by two independent adjudicators blinded to the type of local anesthetic. A sensitivity analysis compared the incidence of a single sign/symptom possibly related to anesthetic toxicity. RESULTS: A total of 924 surgical cases were included in the final analysis (356 liposomal bupivacaine and 568 plain bupivacaine cases). The primary outcome did not occur in any patient. The sensitivity analysis found three cases in the liposomal bupivacaine group and two cases in the plain bupivacaine group having a single sign/symptom possibly related to local anesthetic administration (relative risk 2.4, 95% CI 0.4-14.0, P = 0.38). CONCLUSION: In a cohort of pediatric surgical patients receiving wound infiltration with either plain or liposomal bupivacaine, we identified no cases of local anesthetic systemic toxicity syndrome, and only few patients with any sign or symptom that could potentially be related to local anesthetic toxicity.

Comparison of Topical Versus Peribulbar Anesthesia for 23G Pars Plana Vitrectomy.

OBJECTIVE: To compare the safety and efficacy of topical anesthesia versus peribulbar anesthesia for 23-gauge pars plana vitrectomy. STUDY DESIGN: Randomized controlled trial. PLACE AND DURATION OF STUDY: Ophthalmology Department, Lahore General Hospital, Ameer-ud-Din Medical College, Postgraduate Medical Institute, Lahore from April 2013 to March 2016. METHODOLOGY: A total of 110 patients were equally divided (n=55) in group A (topical anesthesia) and group B (peribulbar anesthesia). In group A, pledget soaked with 0.5% proparacaine hydrochloride were placed in the superior and inferior fornices three minutes before surgery, and removed just before surgery. For group B patients, 3 ml of 0.5% bupivacaine was used for peribulbar anesthesia three minutes before surgery. Surgical time was noted from the placement of pledget in fornix till the eye pad placed in group A, and from the time of peribulbar anesthesia in group B till the eye pad placed at the end of surgery. All data was recorded in Excel sheet and p-values were calculated using online OpenEpi. RESULTS: The mean age of the patient was 56.28 ±13.76 years. Male patients were 78 (70.9%) and female patients were 32 (29.1%). Mean duration of surgery was 30.32 ±7.07 minutes and mean pain score was 2.30 ±0.98. There was a significant difference with respect to mean duration of surgery in patients who were given topical anesthesia (32.52 ±6.92 minutes) versus those given peribulbar anesthesia (28.12 ±6.57 minutes, p<0.001). Mean pain score in topical anesthesia group (3.11 ±0.89) was significantly higher as compared to peribulbar anesthesia group (2.67 ±0.91, p=0.011). CONCLUSION: Topical anesthesia is as effective as peribulbar anesthesia in terms of patient comfort and duration of surgery for 23-G pars plana vitrectomy in patients with vitreous hemorrhage.

Lipid Emulsion, More Than Reversing Bupivacaine Cardiotoxicity: Potential Organ Protection.

Efforts to develop a treatment for bupivacaine cardiotoxicity led to the discovery that Intralipid, a popular brand of intravenous lipid emulsion, could be used not only as an effective treatment for anesthetic-induced cardiac arrest, but also as a means of reversing many other toxicities. Contradictory data exist regarding the mechanism of action of lipid emulsion, a combination of fatty acids traditionally used in parenteral nutrition. Some researchers attribute the effects to lipophilicity and the individual characteristics of the lipids, while other data demonstrate a direct empowering mechanism through cellular upstream and downstream pathways. Understanding the underlying mechanism of action of this safe source of calories may assist in the development of novel organ protective agents. In this review, some of the direct cardiac effects of lipid emulsion are briefly discussed. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Lipid resuscitation in acute poisoning: after a decade of publications, what have we really learned?

PURPOSE OF REVIEW: The decision to provide intravenous lipid emulsion (ILE) therapy as a treatment modality for the reversal of various drug toxicity was discovered in the last decade. Numerous publications, in both humans and animals attest to its clinical use, but current supporting evidence is inconsistent. RECENT FINDINGS: A recent systematic review reported evidence for benefit of ILE in bupivacaine toxicity. Human randomized trials, large observational studies as well as animal models of orogastric poisoning failed to report a clear benefit of ILE for nonlocal anesthetics poisoning. SUMMARY: ILE can be used to resuscitate local anesthetics especially bupivacaine. The impact of ILE on oral overdoses is controversial and clear evidence on benefit is lacking. A thorough risk benefit assessment with consideration of alternative options is warranted to minimize the risk of adverse effects. Evidence supports using bolus doses of ILE, while infusion rates are still debatable.

Intralipid Restoration of Myocardial Contractions Following Bupivacaine-Induced Asystole: Concentration- and Time-Dependence In Vitro.

BACKGROUND: The concentration- and time-response relationships of lipid emulsion (LE; Intralipid) on the recovery of myocardial contractility following bupivacaine (BPV)-induced asystole are poorly defined. METHODS: After achieving asystole by 500-µM BPV, varied concentrations of LE were applied to determine the recovery of stimulated contractile responses and contractions in the cardiac tissues of guinea pigs at a 1.2-Hz stimulation rate. These experiments were performed with LE in either a recirculating (2%-16%) or washout (nonrecirculating) condition (0.05%-12%) for 60 minutes. The effect of LE itself (0.05%-12%) was examined. Oxfenicine was used to evaluate the metabolic action of LE to reverse asystole. BPV concentrations in solution and myocardial tissues were measured. RESULTS: In the recirculation condition, partial recovery of contractile forces was observed for 60 minutes at 4%, 8%, and 12% LE. A contracture followed after exposure to 16% LE in some asystolic muscles. In the washout experiments, following asystole, LE (0.05%-12%) had no effect on the recovery time of the first and regular contractile responses. LE (0.1%-8%) restored contractility to baseline levels after 45 minutes; partial recovery was shown with lower (0.05%) and higher (12%) concentrations. Oxfenicine did not alter the recovery of contractile forces. Contractile depression was observed with 12% LE alone. Concentration-related reduction of tissue BPV concentration by LE was observed in both circulating conditions. CONCLUSIONS: LE induced time- and concentration-dependent recovery of stimulated myocardial contractions from BPV-induced asystole. The lipid uptake effect, along with other undefined mechanisms of LE, seems to contribute to the recovery of contractile function; however, the LE effect on myocardial metabolism is less likely involved at this concentration (500 µM) of BPV.