The reactivity of cyclopropyl cyanide in titan's atmosphere: a possible pre-biotic mechanism.

Cyclopropyl cyanide and other simple nitriles detected in Titan's atmosphere could be precursors leading to the formation of organic macromolecules in the atmosphere of Saturn's largest satellite. Proposing a thermodynamically possible mechanism that explains their formation and supports experimental results represents a difficult challenge. Experiments done in the Atomic and Molecular Physics Laboratory at the University of Trento (AMPL) have studied the ion-molecule reaction between cyclopropyl cyanide and its protonated form, with reaction products being characterized by mass spectrometry. In addition to the expected ion-molecule adduct stabilized by non-covalent long-range interactions, in this work we prove that another distinct species having the same mass to charge ratio (m/z) of 135 is also produced. Moreover, from a previous study of the neutral cyclopropyl cyanide potential energy surface (PES) which shows a partial biradical character it has been possible to characterize the formation through the bimolecular reaction of a new covalent cyclic organic molecule. Calculations have been carried out at the ab initio Møller-Plesset (MP2) level of theory, ensuring the connectivity of the stationary points by using the intrinsic reaction coordinate (IRC) procedure. In order to characterize the reaction transition state, multireference calculations were done using a complete active space involving six electrons and six molecular orbitals [CAS (6 e-, 6 m.o.)]. This study opens the possibility of exploring the formation of new organic molecules by gaseous phase ion-molecule interaction schemes, with such molecules having relevance in interstellar space and in astrobiology (and may be involved in prebiotic molecular evolution).

The role of Li+ ions in the gas phase dehydrohalogenation and dehydration reactions of i-C3H7Br and i-C3H7OH molecules studied by radiofrequency-guided ion beam techniques and ab initio methods.

Gas phase reactive collisions between lithium ions and i-C3H7X (X = Br, OH) molecules have been studied under single collision conditions in the center of mass (CM) 0.01-10.00 eV energy range using a radiofrequency-guided ion beam apparatus. Mass spectrometry analysis of the products did show the presence of [C3H6-Li]+, [HX-Li]+, C3H7+, and C2H3+ as well as of the [Li-i-C3H7Br]+ adduct while [Li-i-C3H7OH]+ was hardly detected. For all these reactive processes, the corresponding cross sections have been measured in absolute units as a function of the CM collision energy. Quantum chemistry ab initio calculations done at the second order Möller Plesset level have provided relevant information on the topology of the potential energy surfaces (PESs) where a reaction takes place allowing the characterization of the stationary points on the respective PESs along their reaction pathways. The connectivity of the different stationary points localized on the PESs was ensured by using the intrinsic reaction coordinate (IRC) method, confirming the adiabatic character of the reactions. The main topology features of the reactive PESs, in the absence of dynamical calculations, were used to interpret at the qualitative level the behavior of the experimental excitations functions, evidencing the role played by the potential energy barriers on the experimental dynamics of the reactions. Reaction rate constants at 303.2 K for different reactions have been calculated from measured excitation functions.

Intraneural injection of a test dose of local anesthetic in peripheral nerves - does it induce histological changes in nerve tissue?

BACKGROUND & OBJECTIVES: Most anesthesiologists use the injection of a test dose of local anesthetic in order to evaluate the final needle tip position. Thus, the intraneural injection of a full dose can be avoided. The aim of this study was to analyze whether an intraneural injection of a test dose of bupivacaine could trigger histological changes. METHODS: Intraneural injections under direct vision were performed in 40 brachial plexus nerves in seven anesthetized pigs. Tibial nerves served as positive and negative controls. Two milliliter of bupivacaine 0.5% was injected in three nerves on the left brachial plexus. For control of local anesthetic's toxicity Ringer's solution was applied intraneurally on the right side. After maintaining 48 h of general anesthesia, the nerves were resected. The specimens were processed for histological examination and assessed for inflammation (hematoxylin and eosin stain, CD68-immunohistochemistry) and myelin damage (Kluver-Barrera stain). The degree of nerve injury was rated on a scale from 0 (no injury) to 4 (severe injury). RESULTS: Statistical analysis showed no significant differences between the bupivacaine group [median (interquartile range) 1 (1-1.5)] and the Ringer's solution group [1 (0.5-2) P = 0.772]. Mild myelin alteration was found in 12.5% of all specimens following intraneural injection, irrespective of the applied substance. CONCLUSIONS: "In our experimental study, intraneural injection of 2 ml of bupivacaine or Ringer's solution showed comparable mild inflammation. Nevertheless, inflammation can only be prevented by strictly avoiding nerve perforation followed by intraneural injection, as mechanical nerve perforation is a key factor for evolving inflammation.

Dehydrohalogenation and Dehydration Reactions of i-C3H7Br and i-C3H7OH by Sodium Ions Studied by Guided Ion Beam Techniques and Quantum Chemical Methods.

Dehydrohalogenation and dehydration reactions of gas-phase i-C3H7Br and i-C3H7OH molecules induced by collision with Na(+), all participants being in their electronic ground state, were studied experimentally in our laboratory using a radiofrequency-guided ion beam apparatus and covering the 0.10-10.00 eV center of mass (CM) energy range. In Na(+) + i-C3H7Br collisions the formation of [C3H6-Na](+) and [HBr-Na](+) by dehydrohalogenation was observed and quantified, as well as that of the ion-molecule adduct [Na-i-C3H7Br](+) together with its decomposition products C3H7(+) and NaBr. In Na(+) + i-C3H7OH collisions the dehydration product [H2O-Na](+) was also found, while [C3H6-Na](+) was hardly detected. Moreover, the [Na-i-C3H7OH](+) adduct formation as well as its decomposition into C3H7(+) and NaOH were also quantified. For all these processes, absolute reaction cross sections were measured as a function of the CM collision energy. From measured excitation functions, rate constants for the formation of [C3H6-Na](+), [HBr-Na](+), and [H2O-Na](+) at 303 K were obtained. Complementing the experiments, exhaustive ab initio structure calculations at the MP2 level of theory were performed, giving information on the most relevant features of the potential energy surfaces (PESs) where the dehydrohalogenation, dehydration, and decomposition reactions take place adiabatically for both collision systems. On these PESs different stationary points associated with potential energy minima and transition state barriers were characterized, and their connectivity was ensured using the intrinsic-reaction-coordinate method. The main topology features of the ab initio calculated PESs allowed a qualitative interpretation of the experimental data also exposing the role of the sodium ion as a catalyst in elimination reactions.

Risk evaluation for needle-nerve contact related to electrical nerve stimulation in a porcine model.

BACKGROUND: For performing peripheral nerve blocks, the risk for needle-nerve contact (NNC) as an adverse event for low and high current thresholds has not yet been clearly defined when nerve stimulator guided techniques were applied. This experimental study aimed to investigate the risk of NNCs when applying stimulation currents between 0.1 and 2 mA (in increments of 0.1 mA). METHODS: Brachial plexus nerves were exposed surgically in five anesthetized pigs. An insulated needle connected to a nerve stimulator was placed at 10 mm distance to the targeted nerves. Current intensity was adjusted according to randomization (0.1-2.0 mA, increments of 0.1 mA). The needle tip was advanced toward the nerve until a motor response was elicited. The frequencies of NNCs for each of the adjusted current intensities were noted. Risks of NNCs were calculated according to the analysis of 95% confidence intervals (95% CI). RESULTS: We executed 2000 needle placements with stimulation currents ranging from 0.1 to 2.0 mA. The risks for NNC at low current intensities were 0.85 (95% CI, 0.77-0.91) for 0.3 mA and 0.5 (95% CI, 0.4-0.6) for 0.5 mA, respectively. For high current intensities, risks of 0.13 (95% CI, 0.07-0.21) for 0.9 mA and 0.01 (95% CI, 0-0.05) for 1.1 mA were calculated. CONCLUSIONS: In this experimental animal study, a relevant reduction in the risk of NNCs could be observed when high current intensities (0.9-1.1 mA) were applied compared to low current intensities (0.3-0.5 mA).

Experimental and ab initio studies of the reactive processes in gas phase i-C3H7Br and i-C3H7OH collisions with potassium ions.

Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic ground state, have been studied in the 0.10-10.00 eV center of mass (CM) collision energy range, using the radiofrequency-guided ion beam technique. In K(+) + i-C3H7Br collisions KHBr(+) formation was observed and quantified, while the analogous KH2O(+) formation in K(+) + i-C3H7OH was hardly detected. Moreover, formation of the ion-molecule adducts and their decomposition leading to C3H7(+) and either KBr or KOH, respectively, have been observed. For all these processes, absolute cross-sections were measured as a function of the CM collision energy. Ab initio structure calculations at the MP2 level have given information about the potential energy surfaces (PESs) involved. In these, different stationary points have been characterized using the reaction coordinate method, their connectivity being ensured by using the intrinsic-reaction-coordinate method. From the measured excitation function for KHBr(+) formation the corresponding thermal rate constant at 303 K has been calculated. The topology of the calculated PESs allows an interpretation of the main features of the reaction dynamics of both systems, and in particular evidence the important role played by the potential energy wells in controlling the reactivity for the different reaction channels.

Feed supplementation with Ligilactobacillus salivarius PS21603 optimises intestinal morphology and gut microbiota composition in weaned piglets.

Post-weaning diarrhoea in piglets remains an important cause of economic losses for swine producers. Feed supplementation with probiotics is one of the alternatives to antibiotics used to reduce the impact of such gastrointestinal disease. The aim of the present study was to evaluate the effect of Ligilactobacillus salivarius PS21603 supplementation on the intestinal structure and the gut microbiota composition of weaned piglets. Safety and tolerance of L. salivarius PS21603 were previously evaluated in a 28-days study using 384 weaned piglets (28 ± 2 days old and 7.5 ± 1.5 kg) divided in three treatment groups: T1: Basal diet + L. salivarius PS21603 109 cfu/day, T2: Basal diet + L. salivarius PS21603 107 cfu/day, and T3: Basal diet (control group). For the present study, 16 piglets per treatment group were randomly selected and faecal samples were collected on day 0 (weaning) and 28 of study. At the end of study, three males and three females per treatment were euthanised. Intestinal morphometric values were measured after necropsy. Faecal counts of Escherichia coli were evaluated by culture techniques, and faecal microbiota composition was assessed by high-throughput sequencing. All data were analysed and compared between treatment groups. Supplementation with L. salivarius PS21603 caused an increase in the intestine length of piglets from T1 and in the villous height:crypt ratio of piglets from T2 (P < 0.05) compared to T3 on day 28. According to the Shannon Diversity Index, microbiota diversity increased on day 28 compared to day 0, with no significant differences observed between treatments. The main changes in the relative abundance of bacteria at the phylum, family, and genus levels were observed between different sampling time points. However, piglets from T1 and T2 had lower faecal E. coli counts than T3 on day 28 (P < 0.05). Moreover, supplementation with L. salivarius PS21603 modulated gut microbiota through a more optimal composition, reducing Escherichia and increasing Bifidobacterium relative abundance in piglets from T1 (P < 0.05) from the beginning to the end of the study. Therefore, the strain L. salivarius PS21603 has shown probiotic properties to be used as feed additive in the pig industry, along with good hygiene and farm management practices, for the prevention and/or treatment of post-weaning diarrhoea in piglets.

Experimental study of the reactive processes in the gas phase K(+) + i-C3H7Cl collisions: a comparison with Li and Na ions.

Reactive collisions between alkali ions (Li(+), Na(+), and K(+)) and halogenated hydrocarbon molecules have been studied recently in our research group. In this paper, we have reported on the K(+) + i-C3H7Cl system in the 0.20-14.00 eV center-of-mass energy range using a radio frequency guided-ion beam apparatus developed in our laboratory. Aiming at increasing our knowledge about this kind of reactions, we compare our latest results for K(+) with those obtained previously for Li(+) and Na(+). While the reaction channels are the same in all three cases, their energy profiles, reactivity, measured reactive cross-section energy dependences, and even their reaction mechanisms, differ widely. By comparing experimentally measured reactive cross-sections as a function of the collision energy with the ab initio calculations for the different potential energy surfaces, a qualitative interpretation of the dynamics of the three reactive systems is presented in the present work.

A comparison and methodological proposal for hybrid approaches to quantify environmental impacts: A case study for renewable energies.

The transition towards a more sustainable and decarbonised energy system is mandatory for achieving global climate objectives, and counting on proper tools to evaluate sustainability is essential. Among sustainability assessment methodologies, hybrid approaches integrating Input-Output analysis (IOA) and Life Cycle Assessment (LCA) are often proposed to overcome limitations and take advantage of strengths of both methodologies. In this paper we propose a new hybrid tiered approach, named Identification and Subtraction Method (ISM). Through a case study of Concentrated Solar Power (CSP) technology, we test the proposed method assessing seven environmental indicators and compare the results obtained by different methodological approaches: Environmental Extended Multiregional Input-Output (EMRIO), LCA and two hybrid approaches. Results showed that, in general, LCA and EMRIO provide the lowest and uppest impact values, respectively. The ISM method expands the LCA boundaries by including indirect impacts, avoiding double-counting and retaining the technological detail and representativeness of the LCA. The main advantage is the ability to establish with high accuracy the impact coming from the LCA system boundaries. Furthermore, ISM is easy to undertake for LCA practitioners, is a low time-consuming hybrid approach once the LCA and EMRIO models are run, and it does not require the alteration of the IO matrix as other hybrid methods. However, the need to perform the EMRIO and LCA analysis could imply high detailed data needs. An additional limitation of the model is that it is not be able to include partial contributions from EMRIO sectors. The highest differences between results obtained by the different methods are found in the assessment of local impacts and the resources depletion, while the methods tend to agree more on global and regional impacts quantification. However, there are limitations to the implementation of the impact characterization methods that should be borne in mind when comparing the results of the different methods.

Crossed molecular beams study of inelastic non-adiabatic processes in gas phase collisions between sodium ions and ZnBr2 molecules in the 0.10-3.50 keV energy range.

Inelastic electronically non-adiabatic reactions between Na(+) ions and neutral ZnBr(2) molecules, both in their electronic ground state, have been studied using crossed beams techniques and measuring the decaying emission radiation of the excited species produced. The fluorescent emission corresponding to Na(3 (2)P) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s (3)S), generated by dissociation of the neutral target molecule, to Zn(4s 4p (3)P). The phosphorescent decaying emission of Zn*(4s 4p (3)P) to the zinc ground state was also observed. For each emission process, the cross section energy dependences have been measured in the 0.10-3.50 keV energy range in the laboratory system. The ground electronic state of the (NaZnBr(2))(+) collision system has been characterized by ab initio chemical structure calculations at the second order Möller-Plesset perturbation level of theory using pseudo-potentials. By performing restricted open shell Hartree-Fock calculations for C(2v) geometries, four singlet and four triplet potential energy surfaces of the system have been calculated and used to interpret qualitatively the observed reactions. A simple two-state dynamical model is presented that allows an estimation of the maximum values for measured cross sections at high collision energies to be made.

Dual guidance improves needle tip placement for peripheral nerve blocks in a porcine model.

BACKGROUND: The objective of the study was to evaluate whether the use of ultrasound (US) together with nerve stimulation (USNST) provides a better needle tip position for performing peripheral regional anaesthesia than the use of US or nerve stimulation (NST) alone. METHODS: Needle placements were applied at the brachial plexus and sciatic nerves in 32 anaesthetised pigs. Following needle placement near the target nerve, using either the USNST or the US or NST, a volume of 0.3 ml synthetic resin was injected mimicking a 'test-dose' injection. The primary outcome was the incidence of close needle-to-nerve placement assessed by injectate localisation in direct contact with the nerve epineurium. Secondary endpoints were the incidences of intraneural injection and haematoma formation in direct contact with the target nerve. RESULTS: A total of 611 punctures were performed. The evaluation for the criterion 'close needle placement' revealed significant differences in favour of the USNST group (98.5%) compared with the NST (90.1%) and the US group (81.6%) (P = 0.001). Significant differences were observed regarding 'intraneural needle placement' between the groups as well (USNST, 0.5%; US, 4%; NST, 2.5%; P = 0.034). The incidence of haematoma formation was significantly higher in the NST group (10.8%) than in the US group (2.5%) and in the USNST group (1.5%) (P = 0.001). CONCLUSION: These findings suggest that the USNST approach combines the benefits of the US and the NST techniques in terms of a higher rate of close needle tip placements and a lower incidence of haematoma formation.

[Continuous paravertebral analgesia versus intravenous analgesia in minimally invasive cardiac surgery by mini-thoracotomy]. / Analgesia paravertebral continua frente a analgesia intravenosa en cirugía cardiaca mínimamente invasiva por minitoracotomía.

OBJECTIVES: Minimal access cardiac surgery via minithoracotomy aims faster recovery and shorter hospital length of stay. Pain control is essential in order to achieve this goal. A study was conducted to assess the quality of post-operative analgesia and complications related to the analgesia techniques after cardiac surgery by minithoracotomy. MATERIAL AND METHODS: A descriptive, observational and retrospective study was conducted on the patients subjected to minimal access cardiac surgery in our centre between the years 2009 to 2011. The patients were divided into two groups according to the type of analgesia received: analgesia through a paravertebral catheter, with an infusion of local anaesthetics (PVB group), and intravenous analgesia with opioids (IOA group). The aim of the study was to compare the analgesic quality and the complications associated to the analgesic technique, extubation time, post-surgical complications, and length of hospital stay between both techniques. RESULTS: A total of 37 patients underwent to a modified minimally invasive Heart-Port access cardiac surgery. Fifteen patients received analgesia through a paravertebral block and the other 22 IV analgesia with opioids. Data are shown as means and standard deviation (SD). Mean tracheal extubation time less than 4 hours was observed in 60% of the patients in the PVB group, compared to 22% in the IOA group (P<.05). Length of stay in ICU for the PVB group was 1.2 (0.7) days compared to 2.2 (0.7) days in the IOA group (P<.05). Mean hospital stay was 4.8 (1.2) days for the PVB group, and 5.6 (2.8) for the IOA group (P>.05. No complications associated to the continuous paravertebral block were observed. DISCUSSION: PVB analgesia is an acceptable safe technique in cardiac surgery via thoracotomy which enables early extubation with optimal pain control when compared with IV analgesia with opioids.

Safety assessment and characterisation of Ligilactobacillus salivarius PS21603 as potential feed additive for swine.

The present study aimed to characterise in vitro properties of the strain Ligilactobacillus salivarius PS21603 and evaluate in vivo piglets' tolerance for its use as feed additive in swine. The ability of L. salivarius PS21603 of inhibiting enteropathogens' growth in vitro was evaluated using a co-culture assay. Low pH tolerance, bile tolerance, and resistance to osmotic changes were evaluated. The antibiotic susceptibility profile of L. salivarius PS21603 was assessed through broth microdilution method. Whole genome sequencing (WGS) was performed to exclude the presence of antibiotic resistance genes. L. salivarius PS21603 showed a high antimicrobial activity in vitro, reducing in a mean of 6.16 log cfu/ml eight different enterotoxigenic Escherichia coli strains. Moreover, L. salivarius PS21603 showed resistance to osmotic changes and was able to survive to a pH above 3.5 during 24 h and up to pH 2 at least during 2 h. In addition, WGS revealed that L. salivarius PS21603 did not harbour any resistance genes and thus there was no risk of transmissibility. Finally, an in vivo 28-days safety and tolerance study was performed. For that, 384 healthy piglets (28±2 days old and 7.5±1.5 kg, at weaning) were divided into three treatment groups receiving a different dose of L. salivarius PS21603: T1, 109 cfu/day; T2, 107 cfu/day; T3, control. Piglet's health status was daily controlled. Individual bodyweight and feed intake per pen were weekly recorded to determine performance parameters. Blood samples were collected in 16 piglets from each treatment group on days 0 and 28 for determination of cytokine profiles. L. salivarius PS21603 was safe and well tolerated by piglets, there were no differences in performance nor cytokine profile between treatment groups. In conclusion, L. salivarius PS21603 is a potential candidate for a probiotic prevention strategy against pig diarrhoea.

Diagnostic-therapeutic algorithm for thrombotic microangiopathy. A report of two cases.

Thrombotic microangiopathies (TMA) are a group of clinical syndromes associated with haemolytic anaemia, thrombocytopenia and organ dysfunction, mainly renal or neurological. They are associated with significant morbidity and mortality, so early diagnosis and treatment are essential. In this article we report two cases of TMA; a patient with thrombotic thrombocytopenic purpura (TTP) and a patient with atypical haemolytic uraemic syndrome (aHUS).

Reactive processes in gas phase Na(+)-iso-C3H7Cl collisions: experimental guided-ion-beam and ab initio studies of the reactions on the ground singlet potential surface of the system up to 12.00 eV.

Reactive processes, taking place when sodium ions collide with neutral iso-C(3)H(7)Cl molecules in the 0.02-12.00 eV range of energies in the center of mass frame, have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. A dehydrohalogenation reaction channel leading to Na(C(3)H(6))(+) formation has been observed up to 1.00 eV while another process producing NaHCl(+) continues up to 4.00 eV. Furthermore, C(3)H(7)(+) formation resulting from decomposition of the reactants, ion-molecule adducts, has also been observed as well as its decomposition into C(2)H(3)(+) on increasing collision energy. Cross-section energy dependences for all these reactions have been obtained in absolute units. The ab initio electronic structure calculations have been done at the MP2 level for the colliding system ground singlet potential surface, giving information on the reactive surface main topological features. From the surface reactants side to the products' one, different potential wells and barriers have been characterized and their connectivity along the reaction evolution has been established using the intrinsic-reaction-coordinate method, thus interpreting the dynamical evolution of the reactants' collision complex to products. Experimental results demonstrate that NaHCl(+) can be produced via different channels. Reaction rate constants at 308.2 K for both dehydrohalogenation reactions have been calculated from measured excitation functions. It has been also confirmed that the reactants adduct decomposition giving C(3)H(7)(+) and NaCl takes place on the same potential surface. A qualitative interpretation of the experimental results in terms of ab initio calculations is also given.

Cross-section energy dependence of the [C6H6-M]+ adduct formation between benzene molecules and alkali ions (M = Li, Na, K).

The association reactions of benzene molecules with alkali ions M(+) (Li(+), Na(+) and K(+)) under single collision conditions have been studied using a radiofrequency-guided-ion-beam apparatus and mass spectrometry characterization of the different adducts. Cross-section energy dependences for [M-C(6)H(6)](+) adduct formation have been measured at collision energies up to 1.20 eV in the center of mass frame. All excitation functions decrease when collision energy increases, showing the expected behaviour for barrierless reactions. From ab initio chemical structure calculations at the MP2(full) level, the formation of the adducts makes evident the alkali ion-benzene non-covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates and unimolecular decomposition on the stabilization of the energized collision complex are also discussed.

Three-dimensional magnetic resonance image of structures enclosed in the spinal canal relevant to anesthetists and estimation of the lumbosacral CSF volume.

Three-dimensional (3D) image-reconstruction of structures inside the spinal canal certainly produces relevant data of interest in regional anesthesia. Nowadays, all hospital MRI equipment is designed mainly for clinical diagnostic purposes. In order to overcome the limitations we have produced more accurate images of structures contained inside the spinal canal using different software, validating our quantitative results with those obtained with standard hospital MRI equipment. Neuroanatomical 3D reconstruction using Amira software, including detailed manual edition was compared with semi-automatic 3D segmentation for CSF volume calculations by commonly available software linked to the MR equipment (MR hospital). Axial sections from seven patients were grouped in two aligned blocks (T1 Fast Field Eco 3D and T2 Balance Fast Field Eco 3D-resolution 0,65 x 0,65 x 0,65 mm, 130 mm length, 400 sections per case). T2 weighted was used for CSF volume estimations. The selected program allowed us to reconstruct 3D images of human vertebrae, dural sac, epidural fat, CSF and nerve roots. The CSF volume, including the amount contained inside nerve roots, was calculated. Different segmentation thresholds were used, but the CSF volume estimations showed high correlation between both teams (Pearson coefficient = 0.98, p = 0.003 for lower blocks; Pearson 0.89, p = 0.042 for upper blocks). The mean estimated value of CSF volume in lower blocks (L3-S1) was 15.8 + 2.9 ml (Amira software) and 13.1 +/- 1.9 ml (software linked to the MR equipment) and in upper blocks (T11-L2) was 21 +/- 4.47 ml and 18.9 +/- 3.5 ml, respectively. A high variability was detected among cases, without correlation with either weight, height or body mass index. Aspects concerning the partial volume effect are also discussed. Quick semi-automatic hospital 3D reconstructions give results close to detailed neuroanatomical 3D reconstruction and could be used in the future for individual quantification of lumbosacral CSF volumes and other structures for anesthetic purposes.

[Late-onset postpartum sepsis with septic shock and heart dysfunction]. / Sepsis puerperal tardía con shock séptico y disfunción cardiaca.

We report a case of late-onset postpartum sepsis from endometritis due to group A streptococci (GAS) in a 37-year-old white woman. The patient developed septic shock, with mitral regurgitation and cardiac dysfunction. Early treatment with broad-spectrum antibiotics and hemodynamic support was essential for a favorable outcome. Because of the resurgence of virulent strains of GAS that can cause fatal infections, these pathogens should be included in the differential diagnosis of postpartum infections in the mother. Although cardiac dysfunction is rare in association with GAS infection, it should be ruled out by echocardiography when the condition of a patient with sepsis does not improve.

[Spinal cord protection during open and endovascular surgery in thoracic and thoracoabdominal aorta diseases]. / Protección medular en la cirugía abierta y endovascular de las enfermedades de la aorta torácica y toracoabdominal.

In recent decades great advances have been made in surgical procedures for treating thoracic and thoracoabdominal aorta defects. Associated mortality and morbidity rates have dropped considerably, mainly in major reference centers, but nonetheless continue to be significant. The need for new strategies to reduce mortality and morbidity has made endovascular approaches an attractive alternative for high-risk surgical patients. The most feared complications of these procedures include paraparesis and paraplegia, which have devastating consequences on patients' quality of life. We provide an updated review of the pathophysiology of spinal cord ischemia in open and endovascular surgery, as well as perioperative measures designed to protect the spinal cord in both types of procedure.

Perioperative diaphragm point-of-care ultrasound as a prediction tool of postoperative respiratory failure in high-risk patients: A feasibility study and case series. / Ecografía diafragmática perioperatoria en el punto de atención como herramienta de predicción de fallo respiratorio postoperatorio en pacientes de alto riesgo: estudio de viabilidad y serie de casos.

INTRODUCTION: Respiratory muscle function in the postoperative period is a key to whether a patient develops Postoperative Respiratory Failure (PRF) or not. PRF occurs when the gas exchange does not meet metabolic needs. Ipsilateral paralysis of the hemidiaphragm after interscalenic brachial plexus block (ISB) causes an acute reduction of respiratory muscle function. This reduction does not cause PRF when the contralateral hemidiaphragm generates enough gas exchange to meet metabolic demands. OBJECTIVES: To study the evolution of hemidiaphragmatic muscle function during the perioperative period with diaphragmatic ultrasound (D-POCUS), and use it as an innovative tool to predict PRF, assessing the contralateral hemidiaphragm in the event of acute hemidiaphragm paralysis. METHODS: Patients considered high risk, scheduled for shoulder surgery with ISB are studied. Both hemidiaphragms were evaluated by ultrasound, before and after the procedure, measuring Thickening Fraction (TF) and Diaphragmatic Excursion (DE). PACU patients with PRF were registered. RESULTS: There was a significant reduction in the TF and DE of the ipsilateral hemidiaphragm in the six patients studied. Only 1/6 patients showed signs of PRF. The evaluation of the contralateral hemidiaphragm during the postoperative period showed that in the five patients without signs of PRF, there were no significant changes in the function of the contralateral hemidiaphragm. The patient, who showed a reduction in contralateral hemidiaphragm function, was the only one who suffered PRF. CONCLUSIONS: In this case series, D-POCUS allows to know the perioperative function of the diaphragm in high-risk patients. All patients suffered an acute reduction of hemidiaphragm function after ISB; however, these patients did not develop PRF when the contralateral hemidiaphragm function was preserved.