Iron(II) Tris-[N4-substituted-3,5-di(2-pyridyl)-1,2,4-triazole] complexes: structural, magnetic, NMR, and density functional theory studies

Eight mononuclear iron(II) complexes of N(4)-3,5-di(2-pyridyl)-1,2,4-triazole (Rdpt) ligands have been prepared and characterized. In all cases the iron(II)/ligand ratio used is 1:3, giving red complexes of the general formula [Fe(II)(Rdpt)(3)](BF(4))(2) x solvents, in 55-89% yield. The ligands differ only in the nature of the N(4)-substituent (amino, pyrrolyl, iso-butyl, methyl, phenyl, para-tolyl, 3,5-dichlorophenyl, and 4-pyridyl; for ligands adpt, pldpt, ibdpt, medpt, phdpt, ptdpt, Cldpt, and pydpt, respectively) allowing substituent effects on the properties of the resulting iron(II) complexes to be probed. The low temperature crystal structures of seven of the complexes reveal low spin iron(II) environments. Packing analyses reveal anion-pi and acetonitrile-pi interactions involving the tetrafluoroborate counteranions and interstitial acetonitrile molecules, respectively. Both "pi-pockets" and "pi-sandwiches" are observed. Solid state magnetic susceptibility measurements (4-300 K) indicate the iron(II) is low spin (LS) in all complexes at all temperatures studied, except for [Fe(II)(pldpt)(3)](BF(4))(2) x 1 1/2 H(2)O which has the beginnings of spin crossover (SCO) at elevated temperatures. Downfield shifts and peak broadening observed in the variable temperature (1)H NMR studies indicate that in d(3)-nitromethane solution the LS [Fe(II)(Rdpt)(3)](2+) complexes are in equilibrium with a trace of a high spin (HS) species. (15)N NMR spectra (measured and calculated) of the ligands reveal that altering the N(4)-substituent changes the chemical shift of the N(1) triazole and pyridine nitrogen atoms, allowing probing of the relationship between ligand substituent and the nature of the coordinating nitrogen atoms

Home peripheral nerve catheters: the first 24 months of experience at a children’s hospital

Andrew Gable,1,2 Candice Burrier,1,3 Jenna Stevens,1 Sharon Wrona,1 Kevin Klingele,4,5 Tarun Bhalla,1,3 David P Martin,1,3 Giorgio Veneziano,1,3 Joseph D Tobias1,3 1Department of Anesthesiology and Pain Medicine, Nationwide Children’s Hospital, Columbus, 2Heritage College of Osteopathic Medicine, Ohio University, Athens, 3Department of Anesthesiology and Pain Medicine, The Ohio State University, 4Department of Orthopedics, Nationwide Children’s Hospital, 5Department of Orthopedics, The Ohio State University, Columbus, OH, USA Context: Home peripheral nerve catheters (PNCs) have become common practice for adult patients after major orthopedic surgery. However, use in pediatric patients is a recent application.Objectives: The purpose of this study was to review the demographics and outcomes of pediatric patients receiving a PNC at our institution.Methods: This retrospective study included patients from October 2012 through October 2014 undergoing orthopedic procedures with a PNC placed for postoperative pain management.Results: A total of 118 patients aged 3.2–25.3 years were identified. The types of catheters included femoral (80.5%), interscalene (11.9%), sciatic (5.9%), and supraclavicular (1.7%). The majority of patients were discharged to home on the day of surgery (77.1%). In the postanesthetic care unit, the average pain score was 2.5, the incidence of nausea/emesis was 5.9%, and the need for opioid administration was 50.8%. There were no major complications. Minor complications included a 7.6% rate of early catheter removal with 5.9% of those due to catheter leakage and an unsecure dressing. There was one case of metallic taste in the mouth without other symptoms of local anesthetic toxicity that resolved without further complication.Conclusion: The implementation of a home PNC program in pediatric patients at our institution has been highly successful with a high rate of ambulatory catheters, low pain scores, low rates of nausea and vomiting, and no serious complications. Minor complications included leaking of the catheter and early discontinuation of the catheter. Keywords: peripheral nerve catheter, pediatric, regional anesthesi

A prospective, double-blinded, randomized comparison of ultrasound-guided femoral nerve block with lateral femoral cutaneous nerve block versus standard anesthetic management for pain control during and after traumatic femur fracture repair in the pediatric population

Nicole M Elsey,1 Joseph D Tobias,1–3 Kevin E Klingele,4 Ralph J Beltran,1,2 Tarun Bhalla,1,2 David Martin,1,2 Giorgio Veneziano,1,2 Julie Rice,1,2 Dmitry Tumin1,2 1Department of Anesthesiology and Pain Medicine, Nationwide Children’s Hospital, 2The Ohio State University, 3Department of Pediatrics, Nationwide Children’s Hospital and The Ohio State University College of Medicine, 4Department of Orthopedic Surgery and Sports Medicine, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA Background: Traumatic injury of the femur resulting in femoral fracture may result in significant postoperative pain. As with other causes of acute pain, regional anesthesia may offer a benefit over conventional therapy with intravenous opioids. This study prospectively assesses the effects of femoral nerve blockade with a lateral femoral cutaneous nerve block (FN-LFCN) on intraoperative anesthetic requirements, postoperative pain scores, and opioid requirements.Materials and methods: Seventeen pediatric patients (age 2–18 years) undergoing surgical repair of a traumatic femur fracture fulfilled the study criteria and were randomly assigned to general anesthesia with either an FN-LFCN block (n = 10) or intravenous opioids (n = 7). All patients received a general anesthetic with isoflurane for maintenance anesthesia during the surgical repair of the femur fracture. Patients randomized to the FN-LFCN block group received ultrasound-guided nerve blockade using ropivacaine (0.2%/0.5% based on patient weight). At the conclusion of surgery, the airway device was removed once tracheal extubation criteria were achieved, and patients were transported to the post-anesthesia care unit (PACU) for recovery and assessment of pain by a blinded study nurse.Results: The final study cohort included 17 patients (n = 10 for FN-LFCN block group; n = 7 for the intravenous opioid group). Although the median of the maximum postoperative pain scores in the regional group was 0, this did not reach statistical significance when compared to the median pain score of 3 in the intravenous opioid group. Likewise, no difference between the two groups was noted when comparing intraoperative anesthetic requirements, opioid requirements (intraoperative, in the post-anesthesia recovery room, and in the inpatient ward), and the time to first opioid requirement postoperatively in the inpatient ward.Conclusion: This prospective, randomized, double-blinded study failed to demonstrate a clear benefit of regional anesthesia over intravenous opioids intraoperatively and postoperatively during repair of femoral shaft fractures in the pediatric population. Keywords: pediatric, femur fracture repair, femoral nerve block &nbsp

Femoral nerve blockade using various concentrations of local anesthetic for knee arthroscopy in the pediatric population

Giorgio Veneziano,1,2 Jennifer Tripi,1 Dmitry Tumin,1 Mumin Hakim,1 David Martin,1,2 Ralph Beltran,1,2 Kevin Klingele,3,4 Tarun Bhalla,1,2 Joseph D Tobias1,2 1Department of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital, 2Department of Anesthesiology & Pain Medicine, The Ohio State University College of Medicine, 3Department of Orthopedic Surgery, Nationwide Children’s Hospital, 4Department of Orthopedic Surgery, The Ohio State University College of Medicine, Columbus, OH, USA Background: Femoral nerve blockade (FNB) provides effective postoperative analgesia in children undergoing arthroscopic knee surgery as evidenced by their opioid-sparing effects and decreased postoperative pain scores. Increasing the local anesthetic concentration in peripheral nerve blockade for adults undergoing orthopedic surgery has been shown to be beneficial, increasing block success rate, and providing a longer duration of analgesia. The effect of increasing the concentration of local anesthetic in extremity blocks in children remains largely unexplored.Methods: We retrospectively evaluated the effectiveness of FNB using three concentrations of local anesthetic (ropivacaine 0.2%, bupivacaine 0.25%, and ropivacaine 0.5%) in children and adolescents undergoing arthroscopic knee surgery. The primary outcome evaluated was postoperative opioid consumption before discharge. Secondary outcomes included post-anesthesia care unit (PACU) and hospital discharge times, first pain score in PACU, and the incidence of adverse events.Results: Two hundred and sixty-nine children and adolescents who received a FNB for arthroscopic knee surgery from January 2010 to December 2013 were included for analysis. Local anesthetic used in FNB was ropivacaine 0.2% in 116 (43%) cases, ropivacaine 0.5% in 75 (28%) cases, and bupivacaine 0.25% in 78 (29%) cases. Median postoperative opioid consumption (mg/kg intravenous morphine equivalents) in the ropivacaine 0.5% group was 0 mg/kg (interquartile ranges [IQR]: 0 mg, 0.03 mg/kg) compared to 0.02 mg/kg (IQR: 0, 0.08 mg/kg) in the ropivacaine 0.2% group and 0.01 mg/kg (IQR: 0, 0.08 mg/kg) in the bupivacaine 0.25% group (p=0.009). Median PACU time was shortest in the ropivacaine 0.5% group (47 min; IQR: 36, 68 min) compared to the ropivacaine 0.2% (58 min; IQR: 41, 77) and bupivacaine 0.25% (54 min; IQR: 35, 75 min) groups (p=0.040). Among groups, there were no significant differences in first postoperative pain scores or incidence of nausea and vomiting. No patient in any group experienced a serious adverse event.Conclusion: The results suggest that ropivacaine 0.5% for FNB offers superior postoperative analgesia in the form of decreased postoperative opioid consumption and earlier PACU/hospital discharge, when compared to ropivacaine 0.2% and bupivacaine 0.25% in the pediatric population.Level of evidence: III, Retrospective Comparative Study. Keywords: anesthesia, regional, nerve block, pain, postoperative, local anesthetic, child, adolescen