Efecto analgésico del bloqueo PENG (grupo de nervios pericapsulares) en pacientes con fractura de cadera / Analgesic effect of the PENG BLOCK (pericapsular nervous group) in patients with hip fracture

Ultrasound regional blockade emerged that blocks the branches of the femoral nerve, obturator and accessory obturator that innervate the anterior hip capsule, the PENG block (group of pericapsular nerves), which by its Recent description does not have enough evidence in medical practice. To verify the analgesic effect of the PENG block in patients with hip fracture and its analgesic permanence during the first 10 hours after the block in patients admitted with a diagnosis of hip fracture, at the General Interzonal Hospital of Acute "Dr Oscar E Alende "From Mar del Plata, Argentina, in the months of May to November 2019. A prospective descriptive observational study was carried out with a total of 53 patients, hospitalized patients with a diagnosis of hip fracture, with standardized intravenous analgesic scheme and who have not yet undergone hip surgery. Pain was evaluated with the EVA scale (visual analog scale) prior to the blockage, and then at 30 min and 10 hours after the blockade, 15 ml of 1% lidocaine and 15 ml of bupivacaine at 0 were used. 25%, convex or linear ultrasound probe according to patient weight and 100 mm needle. In order to reproduce and evaluate the pain, the patients had a 30º flexion of the hip. Prior to the blockade, 66% of the patients had severe pain and 34% moderate pain, none presented mild pain or absence, both at thirty minutes and ten hours after the blockade, no patient presented severe pain and all patients presented analgesia with a decrease in more than three points on the VAS scale, in some cases reaching a decrease of 10 points on that scale. The PENG block is a regional anesthesia technique that provides very good analgesia to patients with hip fractures, therefore, it is an excellent saving strategy for systemic analgesics. Knowing the analgesia provided by the blockade at 30 min and at 10 h, it could be performed both in the preoperative period for the transfer and mobilization of the patient, as well as in the postoperative period, which could save the use of opioids and decrease hospital stay.

INTRODUCCIÓN La fractura de cadera es una emergencia ortopédica común en ancianos asociada a gran morbimortalidad, una adecuada analgesia regional perioperatoria determina un ahorro en el uso de analgésicos sistémicos. Recientemente, en el año 2018, surgió un nuevo bloqueo regional ecoguiado muy prometedor que bloquea las ramas del nervio femoral, obturador y obturador accesorio que inervan la capsula anterior de la cadera, el bloqueo PENG (grupo de nervios pericapsulares), el cual por su reciente descripción no cuenta con la suficiente evidencia en la práctica médica. OBJETIVOS: Comprobar el efecto analgésico del bloqueo PENG en pacientes con fractura de cadera y su permanencia analgésica durante las 10 primeras horas posteriores al bloqueo en los pacientes internados con diagnóstico de fractura de cadera, en el Hospital Interzonal General de Agudos "Dr. Oscar E Alende" de Mar del Plata, Argentina, en los meses de mayo a noviembre del 2019. MATERIALES Y MÉTODOS: Se realizó un estudio observacional descriptivo prospectivo con un total de 53 pacientes, se incluyeron pacientes internados con diagnóstico de fractura de cadera, con esquema analgésico endovenoso estandarizado y que aún no hayan sido sometido a cirugía de cadera. Se evaluó el dolor con la escala EVA (escala análoga visual) previo al bloqueo, y luego a los 30 min y a las 10 Hs de haber realizado el bloqueo, para este se utilizaron 15 ml lidocaína 1% y 15 ml de bupivacaína al 0,25%, sonda ecográfica convexa o lineal según el peso del paciente y aguja 100 mm. Para reproducir y evaluar el dolor se les realizo a los pacientes una flexión de 30º de la cadera. RESULTADOS: Previo al bloqueo el 66% de los pacientes tuvieron dolor severo y 34% dolor moderado, ninguno presentaba dolor leve o ausencia del mismo, tanto a los treinta minutos como a las diez horas posteriores al bloqueo ningún paciente presento dolor severo y todos los pacientes presentaron analgesia con una disminución en más de tres puntos en la escala de EVA, llegando en algunos casos a una disminución de 10 puntos de dicha escala. CONCLUSIONES: El bloqueo PENG es una técnica de anestesia regional que brinda muy buena analgesia a los pacientes con fractura de cadera, por consiguiente, es una excelente estrategia ahorradora de analgésicos sistémicos. Conociendo la analgesia que brinda el bloqueo a los 30 min y a las 10 h de realizado, se podría realizar dicho bloqueo tanto en el preoperatorio para el traslado y movilización del paciente, como en el post-operatorio, lo que podría ahorrar el uso de opioides y disminuir la estancia hospitalaria.

Prediction of proton affinities of organic molecules using the any-particle molecular-orbital second-order proton propagator approach.

We assess the performance of the recently developed any-particle molecular-orbital second-order proton propagator (APMO/PP2) scheme [M. Díaz-Tinoco, J. Romero, J. V. Ortiz, A. Reyes and R. Flores-Moreno, J. Chem. Phys., 2013, 138, 194108] on the calculation of gas phase proton affinities (PAs) of a set of 150 organic molecules comprising several functional groups: amines, alcohols, aldehydes, amides, ketones, esters, ethers, carboxylic acids and carboxylate anions. APMO/PP2 PAs display an overall mean absolute error of 0.68 kcal mol-1 with respect to experimental data. These results suggest that the APMO/PP2 method is an alternative approach for the quantitative prediction of gas phase proton affinities. One novel feature of the method is that a PA can be obtained from a single calculation of the optimized protonated molecule.

Calculation of positron binding energies using the generalized any particle propagator theory.

We recently extended the electron propagator theory to any type of quantum species based in the framework of the Any-Particle Molecular Orbital (APMO) approach [J. Romero, E. Posada, R. Flores-Moreno, and A. Reyes, J. Chem. Phys. 137, 074105 (2012)]. The generalized any particle molecular orbital propagator theory (APMO/PT) was implemented in its quasiparticle second order version in the LOWDIN code and was applied to calculate nuclear quantum effects in electron binding energies and proton binding energies in molecular systems [M. Díaz-Tinoco, J. Romero, J. V. Ortiz, A. Reyes, and R. Flores-Moreno, J. Chem. Phys. 138, 194108 (2013)]. In this work, we present the derivation of third order quasiparticle APMO/PT methods and we apply them to calculate positron binding energies (PBEs) of atoms and molecules. We calculated the PBEs of anions and some diatomic molecules using the second order, third order, and renormalized third order quasiparticle APMO/PT approaches and compared our results with those previously calculated employing configuration interaction (CI), explicitly correlated and quantum Montecarlo methodologies. We found that renormalized APMO/PT methods can achieve accuracies of ~0.35 eV for anionic systems, compared to Full-CI results, and provide a quantitative description of positron binding to anionic and highly polar species. Third order APMO/PT approaches display considerable potential to study positron binding to large molecules because of the fifth power scaling with respect to the number of basis sets. In this regard, we present additional PBE calculations of some small polar organic molecules, amino acids and DNA nucleobases. We complement our numerical assessment with formal and numerical analyses of the treatment of electron-positron correlation within the quasiparticle propagator approach.

A generalized any-particle propagator theory: prediction of proton affinities and acidity properties with the proton propagator.

We have recently extended the electron propagator theory to the treatment of any type of particle using an Any-Particle Molecular Orbital (APMO) wavefunction as reference state. This approach, called APMO/PT, has been implemented in the LOWDIN code to calculate correlated binding energies, for any type of particle in molecular systems. In this work, we present the application of the APMO/PT approach to study proton detachment processes. We employed this method to calculate proton binding energies and proton affinities for a set of inorganic and organic molecules. Our results reveal that the second-order proton propagator (APMO/PP2) quantitatively reproduces experimental trends with an average deviation of less than 0.41 eV. We also estimated proton affinities with an average deviation of 0.14 eV and the proton hydration free energy using APMO/PP2 with a resulting value of -270.2 kcal/mol, in agreement with other results reported in the literature. Results presented in this work suggest that the APMO/PP2 approach is a promising tool for studying proton acid/base properties.

Microsolvation of Mg²âº, Ca²âº: strong influence of formal charges in hydrogen bond networks.

A stochastic exploration of the quantum conformational spaces in the microsolvation of divalent cations with explicit consideration of up to six solvent molecules [Mg (H2O)n)](2+), (n=3, 4, 5, 6) at the B3LYP, MP2, CCSD(T) levels is presented. We find several cases in which the formal charge in Mg²âº causes dissociation of water molecules in the first solvation shell, leaving a hydroxide ion available to interact with the central cation, the released proton being transferred to outer solvation shells in a Grotthus type mechanism; this particular finding sheds light on the capacity of Mg²âº to promote formation of hydroxide anions, a process necessary to regulate proton transfer in enzymes with exonuclease activity. Two distinct types of hydrogen bonds, scattered over a wide range of distances (1.35-2.15 Å) were identified. We find that in inner solvation shells, where hydrogen bond networks are severely disturbed, most of the interaction energies come from electrostatic and polarization+charge transfer, while in outer solvation shells the situation approximates that of pure water clusters.

A generalized any particle propagator theory: assessment of nuclear quantum effects on electron propagator calculations.

In this work we propose an extended propagator theory for electrons and other types of quantum particles. This new approach has been implemented in the LOWDIN package and applied to sample calculations of atomic and small molecular systems to determine its accuracy and performance. As a first application of the method we have studied the nuclear quantum effects on electron ionization energies. We have observed that ionization energies of atoms are similar to those obtained with the electron propagator approach. However, for molecular systems containing hydrogen atoms there are improvements in the quality of the results with the inclusion of nuclear quantum effects. An energy term analysis has allowed us to conclude that nuclear quantum effects are important for zero order energies whereas propagator results correct the electron and electron-nuclear correlation terms. Results presented for a series of n-alkanes have revealed the potential of this method for the accurate calculation of ionization energies of a wide variety of molecular systems containing hydrogen nuclei. The proposed methodology will also be applicable to exotic molecular systems containing positrons or muons.

Understanding microsolvation of Li+: structural and energetical analyses.

A stochastic exploration of the quantum conformational space for the (H(2)O)(n)Li(+), n = 3, 4, 5 complexes produced 32 molecular clusters at the B3LYP/6-311++G** and MP2/6-311++G** levels. The first solvation shell is predicted to comprise a maximum of 4 water molecules. Energy decomposition analyses were performed to determine the relationship between the geometrical features of the complexes and the types of interactions responsible for their stabilization. Our findings reveal that electrostatic interactions are major players determining the structures and relative stabilities of the clusters. The formal charge on the Li atom leads to two distinct types of hydrogen bonds, scattered in a wide range of distances (1.61-2.32 Å), in many cases affording H-bonds that are considerably larger and considerably shorter than those in pure water clusters (typically ∼1.97 Å).

Secondary deuterium isotope effects on the acidity of glycine.

Secondary deuterium isotope effects (IE) on the acidity (pK(a)) of glycine were measured by ¹³C NMR titration. It was found that deuteration decreases the pK(a) by 0.034 ± 0.002. The experimental data are supported by theoretical calculations, which, in turn, allowed to relate the acidity decrease to the lowering of glycine vibrational frequencies upon deuteration.

Utilidad del Eco/Doppler para el análisis del tiempo de relajación isométrica del ventrículo izquierdo en un modelo experimental de reperfusión miocárdica / The utility of Doppler echocardiography in the analysis of left ventricular isometric relaxation time in an experimental model of myocardial reperfusion

Se efectuó el estudio prospectivo de las modificaciones del tiempo de relajación isométrica ventricular izquierda (TRIVI), en un modelo experimental de reperfusión miocárdica (RM), en 19 perrros. Estos se estudiaron con tórax abierto, en asistencia ventilatoria mecánica y monitoreo hemodinámico. Se colocó un catéter intracoronario en el tercio medio de la arteria descendente anterior (DA) para el registro directo de su presión. Se ligó la DA diatalmente a la primera diagonal durante 15 minutos y posteriormente se desligó. Se registraron ECO2D y Doppler pulsado con aproximaciones epicárdicas, en condiciones basales, a los 5 y 15 min de isquemia, a los 5, 15, 30 y 60 min de RM. Se analizaron la movilidad del septum interventricular (SIV) y sus cambios de grosor en sístole (S) y diástole (D). Se midió el TRIVI en todos los períodos mencionados. Para el estudio estadístico, se utilizó la T de Student. No hubo cambios significativos en el grosor S o D del septum interventricular. El TRIVI aumentó al comparar el registro basal con los minutos 5 y 15 de isquemia (p < 0.0001) y hubo regresión del mismo con la RM (p< 0.05). La isquemia miocárdica aguda prolonga el TRIVI. En este modelo, con la RM el TRIVI regresa a la normalidad. La medición del TRIVI puede ser utilizada coomo criterio de reperfusión.