Mortality and major postoperative complications within 1 year after vascular surgery: a prospective cohort study.

INTRODUCTION: Patients undergoing vascular procedures are prone to developing postoperative complications affecting their short­term mortality. Prospective reports describing the incidence of long­term complications after vascular surgery are lacking. OBJECTIVES: We aimed to describe the incidence of complications 1 year after vascular surgery and to evaluate an association between myocardial injury after noncardiac surgery (MINS) and 1­year mortality. PATIENTS AND METHODS: This is a substudy of a large prospective cohort study Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION). Recruitment took place in 28 centers across 14 countries from August 2007 to November 2013. We enrolled patients aged 45 years or older undergoing vascular surgery, receiving general or regional anesthesia, and hospitalized for at least 1 night postoperatively. Plasma cardiac troponin T concentration was measured before the surgery and on the first, second, and third postoperative day. The patients or their relatives were contacted 1 year after the procedure to assess the incidence of major postoperative complications. RESULTS: We enrolled 2641 patients who underwent vascular surgery, 2534 (95.9%) of whom completed 1­year follow­up. Their mean (SD) age was 68.2 (9.8) years, and the cohort was predominantly male (77.5%). The most frequent 1­year complications were myocardial infarction (224/2534, 8.8%), amputation (187/2534, 7.4%), and congestive heart failure (67/2534, 2.6%). The 1­year mortality rate was 8.8% (223/2534). MINS occurred in 633 patients (24%) and was associated with an increased 1­year mortality (hazard ratio, 2.82; 95% CI, 2.14-3.72; P <0.001). CONCLUSIONS: The incidence of major postoperative complications after vascular surgery is high. The occurrence of MINS is associated with a nearly 3­fold increase in 1­year mortality.

Intraoperative Inspiratory Oxygen Fraction and Myocardial Injury After Noncardiac Surgery: Results From an International Observational Study in Relation to Recent Controlled Trials.

BACKGROUND: Two trials reported that a high inspiratory oxygen fraction (F io2 ) does not promote myocardial infarction or death. Observational studies can provide larger statistical strength, but associations can be due to unobserved confounding. Therefore, we evaluated the association between intraoperative F io2 and cardiovascular complications in a large international cohort study to see if spurious associations were observed. METHODS: We included patients from the Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) study, who were ≥45 years of age, scheduled for overnight hospital admission, and had intraoperative F io2 recorded. The primary outcome was myocardial injury after noncardiac surgery (MINS), and secondary outcomes included mortality and pneumonia, all within 30 postoperative days. Data were analyzed with logistic regression, adjusted for many baseline cardiovascular risk factors, and illustrated in relation to findings from 2 recent controlled trials. RESULTS: We included 6588 patients with mean age of 62 years of whom 49% had hypertension. The median intraoperative F io2 was 0.46 (5%-95% range, 0.32-0.94). There were 808 patients (12%) with MINS. Each 0.10 increase in median F io2 was associated with a confounder-adjusted increase in odds for MINS: odds ratio (OR), 1.17 (95% confidence interval [CI], 1.12-1.23; P < .0001). MINS occurred in contrast with similar frequencies and no significant difference in controlled trials (2240 patients, 194 events), in which patients were given 80% vs 30% oxygen. Mortality was 2.4% and was not significantly associated with a median F io2 (OR, 1.07; 95% CI, 0.97-1.19 per 0.10 increase; P = .18), and 2.9% of patients had pneumonia (OR, 1.05; 95% CI, 0.95-1.15 per 0.10 increase; P = .34). CONCLUSIONS: We observed an association between intraoperative F io2 and risk of myocardial injury within 30 days after noncardiac surgery, which contrasts with recent controlled clinical trials. F io2 was not significantly associated with mortality or pneumonia. Unobserved confounding presumably contributed to the observed association between F io2 and myocardial injury that is not supported by trials.

Association between emergency department length of stay and adverse perioperative outcomes in emergency surgery: a cohort study in two Colombian University hospitals.

BACKGROUND: In low- and middle-income countries emergency surgery represents a higher proportion of the total number of surgeries and is associated with greater morbidity/mortality. Study aims were to determine if emergency department length of stay (ED-LOS) was associated with adverse perioperative outcomes and if such association varied across patient's risk categories. METHODS: A retrospective cohort study was conducted of adult patients who underwent orthopedic or abdominal emergency surgery at two Colombian University hospitals. The population comprised a mix of a representative sample of eligible cases, with unselected patients (2/3), enriched with a high-risk subset (1/3). ED-LOS was defined as the interval between emergency department arrival and surgery start time. Our primary outcome was an adverse perioperative outcome during hospitalization, which was a composite of in-hospital mortality or severe complications such as major cardiovascular adverse events, infection, renal failure and bleeding. RESULTS: Among 1487 patients analyzed, there were 519 adverse perioperative outcomes including 150 deaths. In the unselected sample (n = 998) 17.9% of patients presented an adverse perioperative outcome with a mortality of 4.9%. The median ED-LOS was 24.6 (IQR 12.5-53.2) hours. ED-LOS was associated with age, comorbidities and known risk factors for 30-day mortality. Patients developing an adverse perioperative outcome started surgery 27.1 h later than their counterparts. Prolonged ED-LOS increased the risk of an adverse perioperative outcome in patients without risk factors (covariate-adjusted OR = 2.52), while having 1-2 or 3+ risk factors was negatively associated (OR = 0.87 and 0.72, respectively, p < 0.001 for the interaction). CONCLUSION: Prolonged ED-LOS is associated with increased adverse perioperative outcome for patients without risk factors for mortality, but seems protective and medically justified for more complex cases.

Corrigendum to "Caffeine's Vascular Mechanisms of Action".

[This corrects the article DOI: 10.1155/2010/834060.].

Myocardial Injury After Noncardiac Surgery (MINS) in Vascular Surgical Patients: A Prospective Observational Cohort Study.

OBJECTIVE: To determine the prognostic relevance, clinical characteristics, and 30-day outcomes associated with myocardial injury after noncardiac surgery (MINS) in vascular surgical patients. BACKGROUND: MINS has been independently associated with 30-day mortality after noncardiac surgery. The characteristics and prognostic importance of MINS in vascular surgery patients are poorly described. METHODS: This was an international prospective cohort study of 15,102 noncardiac surgery patients 45 years or older, of whom 502 patients underwent vascular surgery. All patients had fourth-generation plasma troponin T (TnT) concentrations measured during the first 3 postoperative days. MINS was defined as a TnT of 0.03 ng/mL of higher secondary to ischemia. The objectives of the present study were to determine (i) if MINS is prognostically important in vascular surgical patients, (ii) the clinical characteristics of vascular surgery patients with and without MINS, (iii) the 30-day outcomes for vascular surgery patients with and without MINS, and (iv) the proportion of MINS that probably would have gone undetected without routine troponin monitoring. RESULTS: The incidence of MINS in the vascular surgery patients was 19.1% (95% confidence interval (CI), 15.7%-22.6%). 30-day all-cause mortality in the vascular cohort was 12.5% (95% CI 7.3%-20.6%) in patients with MINS compared with 1.5% (95% CI 0.7%-3.2%) in patients without MINS (P < 0.001). MINS was independently associated with 30-day mortality in vascular patients (odds ratio, 9.48; 95% CI, 3.46-25.96). The 30-day mortality was similar in MINS patients with (15.0%; 95% CI, 7.1-29.1) and without an ischemic feature (12.2%; 95% CI, 5.3-25.5, P = 0.76). The proportion of vascular surgery patients who suffered MINS without overt evidence of myocardial ischemia was 74.1% (95% CI, 63.6-82.4). CONCLUSIONS: Approximately 1 in 5 patients experienced MINS after vascular surgery. MINS was independently associated with 30-day mortality. The majority of patients with MINS were asymptomatic and would have gone undetected without routine postoperative troponin measurement.

Efecto del ejercicio aeróbico en la rigidez vascular en una población sana / Effect of aerobic exercise in vascular stiffness in healthy population

Resumen Introducción: Un estilo de vida saludable es determinante para la salud cardiovascular. Existe controversia en los efectos vasculares benéficos del ejercicio físico. Objetivo: Evaluar el comportamiento de los parámetros de rigidez vascular en una población sana que practica ejercicio aeróbico rutinario en comparación con una población sana sedentaria. Métodos: Estudio de 32 sujetos sanos, pareados por edad y sexo: 12 hombres y 20 mujeres (46,3 ± 9,7 años), en el cual se evaluaron y compararon los parámetros de rigidez arterial (presión sistólica y diastólica braquial, índices de aumentación braquial y central, velocidad de onda de pulso, presión sistólica y diastólica central, y presión de pulso braquial y central). Las mediciones se hicieron con el método no invasivo-oscilométrico, Arteriograph® (TensioMed Budapest Hungría, Ltd.). Resultados: Se compararon los parámetros de rigidez arterial entre los dos grupos (16 sujetos activos vs. 16 sedentarios), y se encontraron diferencias significativas en los siguientes: frecuencia cardiaca de 53,25 ± 8,0 lpm vs. 59,75± 8,6 lpm (p = 0,034), presión arterial diastólica braquial de 70,0 (4,5) mm Hg vs. 77,5 (8,3) mm Hg (p = 0,043), presión arterial diastólica central de 70,0 (4,5) mm Hg vs. 77,5 (8,1) mm Hg (p = 0,043) y velocidad de onda de pulso de 6,70 (1,1) m/s vs. 7,75 (1,1) m/s (p = 0,001). Conclusiones: La actividad física aeróbica rutinaria tiene un efecto benéfico sobre la rigidez vascular en una población sana, a expensas de una disminución significativa de la velocidad de onda de pulso, la frecuencia cardiaca y la presión arterial diastólica (braquial y central). Estos hallazgos ayudan a explicar los beneficios del ejercicio aeróbico sobre el sistema cardiovascular.

Abstract Introduction: A healthy lifestyle is key for cardiovascular health. There is controversy about beneficial vascular effects of physical exercise. Motivation: To assess the behaviour of vascular stiffness parametres in a healthy population group that practices routine aerobic exercise in comparison with another group of healthy population with a sedentary lifestyle. Methods: Study of 32 healthy individuals, paired according to age and gender: 12 men and 20 women (46.3±9.7 years old); the study assessed and compared arterial stiffness parametres (brachial systolic and diastolic blood pressure, brachial and central augmentation index, pulse wave velocity, central systolic and diastolic blood pressure and brachial and central pulse pressure).Measurements were conducted using the noninvasive oscillometric method Arteriograph® (TensioMed Budapest Hungary, Ltd.). Results: Arterial stiffness parametres were compared between both groups (16 active individuals vs. 16 sedentary ones), and the following significant differences were found: heart rate 53.25 ± 8.0 bpm vs. 59.75 ± 8.6 bpm (p = 0.034), brachial diastolic blood pressure of 70.0 (4.5) mmHg vs. 77.5 (8.3) mmHg (p = 0.043), central diastolic blood pressure of 70.0 (4.5) mmHg vs. 77.5 (8.1) mmHg (p = 0.043) and pulse wave velocity of 6.70 (1.1) m/s vs. 7.75 (1.1) m/s (p = 0.001). Conclusions: Routine aerobic exercise has a beneficial effect on vascular stiffness in a healthy population group, at the expense of a significant decrease in pulse wave velocity, heart rate and diastolic blood pressure (both brachial and central). These findings help explain the benefits of aerobic exercise on the cardiovascular system.

Risk factors associated with postoperative seizures in patients undergoing cardiac surgery who received tranexamic acid: a case-control study.

Antifibrinolytic agents are used during cardiac surgery to minimize bleeding and reduce exposure to blood products. Several reports suggest that tranexamic acid (TA) can induce seizure activity in the postoperative period. To examine factors associated with postoperative seizures in patients undergoing cardiac surgery who received TA. University-affiliated hospital. Case-control study. Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) between January 2008 and December 2009 were identified. During this time, all patients undergoing heart surgery with CPB received TA. Cases were defined as patients who developed seizures that required initiation of anticonvulsive therapy within 48 h of surgery. Exclusion criteria included subjects with preexisting epilepsy and patients in whom the convulsive episode was secondary to a new ischemic lesion on brain imaging. Controls who did not develop seizures were randomly selected from the initial cohort. From an initial cohort of 903 patients, we identified 32 patients with postoperative seizures. Four patients were excluded. Twenty-eight cases and 112 controls were analyzed. Cases were more likely to have a history of renal impairment and higher preoperative creatinine values compared with controls (1.39 ± 1.1 vs. 0.98 ± 0.02 mg/dL, P = 0.02). Significant differences in the intensive care unit, postoperative and total lengths of stay were observed. An association between high preoperative creatinine value and postoperative seizure was identified. TA may be associated with the development of postoperative seizures in patients with renal dysfunction. Doses of TA should be reduced or even avoided in this population.

Caffeine's Vascular Mechanisms of Action.

Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial.

Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial.

BACKGROUND: The efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV. METHODS: We studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode. RESULTS: PaO2, PaCO2 and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 ± 3.8 cmH2O vs 23.1 ± 4.3 cmH2O; p < 0.001) without any significant differences in mean and plateau pressures. CONCLUSIONS: In patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.

Intubación orotraqueal sin relajante muscular: propofol o etomidato en combinación con remifentanilo / Orotracheal Intubation without the use of muscle relaxant: propofol or etomidate in combination with remifentanil

Introducción. El remifentanilo en combinación con propofol provee adecuadas condiciones para la intubación orotraqueal sin relajante neuromuscular. Otros agentes inductores no han sido adecuadamente evaluados. El propósito del estudio fue evaluar las condiciones de intubación y los cambios hemodinámicos tras la inducción anestésica con remifentanilo-propofol o remifentanilo- etomidato. Métodos. En este estudio prospectivo, doble ciego y aleatorio, participaron 90 pacientes con clasificación ASA I/II. Recibieron 0,03 mg/kg de midazolam y 7 ml/kg de lactato de Ringer, y posteriormente, 3 mg/kg de remifentanilo seguidos de 1 mg/kg de lidocaína. A continuación, se distribuyeron en forma aleatoria en los siguientes grupos de pacientes: los que recibieron 2 mg/kg de propofol (grupo propofol, n=29), 0,3 mg/ kg de etomidato (grupo etomidato 3, n=31) o 0,4 mg/kg de etomidato (grupo etomidato 4, n=30). Después se realizó laringoscopia e intubación orotraqueal. Las condiciones para la intubación se evaluaron utilizando un sistema cualitativo de puntaje. Se registraron la presión arterial media y la frecuencia cardiaca previa a la inducción, posterior a la inducción, inmediatamente después de la intubación y cada minuto hasta 5 minutos después de la intubación. Resultados. Tres pacientes del grupo etomidato 3 y dos del grupo etomidato 4 no pudieron ser intubados en el primer intento. Se alcanzaron condiciones clínicamente aceptables de intubación en 100%, 74% y 80%, en los grupo propofol, etomidato 3 y etomidato 4, respectivamente (p=0,016). El descenso en la presión arterial media fue significativamente mayor en el grupo propofol comparado con el grupo etomidato 3. Conclusiones. Para la intubación orotraqueal sin relajante neuromuscular, el uso de remifentanilo-propofol es superior al de remifentanilo-etomidato, 0,3 mg/kg o 0,4 mg/kg. Con 0,3 mg/kg de etomidato se obtiene un mejor perfil hemodinámico.

Introduction: Remifentanil followed by propofol provides adequate conditions for tracheal intubation without using muscle relaxants. Other hypnotic drugs have not been thoroughly evaluated in this regard. The purpose of this study was to assess intubating conditions and cardiovascular changes after induction of anesthesia with remifentanil-propofol or. Methods: 90 ASA I/II patients were enrolled in this random, prospective, double-blind study. Subjects received 0.03 mg/kg of midazolam followed by a 7 ml/kg infusion of RingerLs lactate. After that, 3 ƒÊg/kg of remifentanil were injected followed by lydocaine, 1 mg/kg. Then, patients received either propofol (2 mg/ kg) (Propofol Group, n= 29), or etomidate (0.3 mg/kg) (Etomidate 3 Group, n=31) or etomidate (0.4 mg/kg) (Etomidate 4 Group, n=30). Subsequent laryngoscope and intubation were performed. Intubating conditions were assessed using a quality scoring system. Mean arterial pressure and heart rates pre-induction, post-induction were recorded immediately after intubation and every 1 to 5 minutes after intubation. Results: Three patients in the etomidate 3 Group and two patients in the etomidate 4 Group were not able to beintubated in the first attempt. Clinically acceptable intubating conditions were observed in 100%, 74%, 80% in the Propofol, Etomidate 3 and etomodate 4 groups, respectively (p=0.01 6). The decrease in mean arterial pressure was significantly higher in the propofol group as compared to the etomidate 3 group (p<0.05). Conclusions: The use of lydocaine-remifentanil-propofol for tracheal intubation without muscle relaxants is superior to 0.3 or 0.4 mg/kg lydocaine-remifentanil plus etomidate. However, etomidate 0.3 mg/kg produces a better hemodynamic profile when compared to propofol.

The role of potassium channels in the vasodilatory effect of caffeine in human internal mammary arteries.

There is little information about the direct effect of caffeine in human blood vessels. The purpose of this study was to evaluate the direct vascular effect of caffeine on human internal mammary artery (IMA) and the involvement of potassium channels in this response. Segments of IMA were obtained from 29 patients who underwent coronary artery bypass graft surgery. They were cut into rings, suspended between two wire hooks in organ bath chambers and constricted submaximally with norepinephrine. Caffeine (3.16x10(-9) to 10(-4) mol/L) was added in a cumulative fashion to rings with or without functional endothelium and concentration response curves were constructed. The response to caffeine was also evaluated after incubation with adenosine 3',5'-triphosphate (ATP)-dependent potassium channel blocker glibenclamide, voltage-dependent potassium channel blocker 4-aminopyridine and large-conductance calcium-activated potassium channel inhibitor tetraethylammonium. Caffeine produced a potent, concentration-dependent relaxation of IMA. The relaxant responses did not differ significantly between endothelium-intact and endothelium-denuded preparations. Incubation with different potassium channel inhibitors (glibenclamide, 4-aminopyridine and tetraethylammonium) did not cause significant alterations in the relaxant responses to caffeine. These results suggest that the vasodilatory response to caffeine in human IMA is independent of endothelial function and is not mediated by potassium channels.

Comparison of spinal anesthesia with combined sciatic-femoral nerve block for outpatient knee arthroscopy.

STUDY OBJECTIVE: To compare spinal anesthesia and combined sciatic-femoral nerve block for outpatient knee arthroscopy. DESIGN: Prospective, randomized, controlled study. SETTING: Postoperative recovery area at a university-affiliated medical center. PATIENTS: 50 ASA physical status I and II adult outpatients undergoing arthroscopic knee surgery. INTERVENTIONS: Study subjects were equally divided (n = 25 each) into spinal and sciatic-femoral groups. Spinal group patients received spinal anesthesia with 7.5 mg of 0.5% hyperbaric bupivacaine. Sciatic-femoral group patients received combined sciatic-femoral nerve blocks using a mixture of 20 mL of lidocaine 2% plus 20 mL of bupivacaine 0.5%. MEASUREMENTS: Times including that from arrival in the operating room to readiness for surgery, duration of surgery, recovery time, and patient satisfaction were recorded. Analgesia and occurrence of adverse events also were recorded. MAIN RESULTS: No significant differences between the two groups were found for any of the study measurements of recovery. After discharge, postoperative pain differed significantly between groups only at 6 hours (P < 0.002). Patient satisfaction was high with both techniques. CONCLUSIONS: Combined sciatic-femoral nerve block for outpatient arthroscopic knee surgery offers satisfactory anesthesia, with a clinical profile similar to that of low-dose spinal anesthesia. Sciatic-femoral nerve blocks are associated with significantly lower pain scores during the first 6 postoperative hours.

[In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery]. / Acción in vitro de la cafeína en anillos de arteria mamaria interna utilizada en cirugía de revascularización cardiaca.

INTRODUCTION: The vasodilator effect of caffeine in animal models arteries has been demonstrated previously. However, studies with the same methodology using human arteries in vitro have not been performed. OBJECTIVES: The in vitro vasoactive effects of caffeine was evaluated on human internal mammary arteries. MATERIALS AND METHODS: Internal mammary artery rings were used (n = 20). Endothelial function was evaluated with acetylcholine at a concentration of 3.16 x 10 -6 M, nitroglycerine at cumulative concentrations of 10 -11 M to 10 -4 M and caffeine with cumulative concentrations of 10 -8 M to 10 -4 M. RESULTS: Nitroglycerin produced a maximum relaxation percentage of 87.4 +/- 12.3%, caffeine a percentage of 86.9 +/- 21.0% in arteries with functional endothelium, and of 71.6 +/- 28.6% in arteries with endothelial dysfunction. No differences were detected among the three groups ( p=0.289). Similarly, no differences were found between EC 50 in arteries with functional endothelium (1.66 x 10 -5 +/-1.57 x 10 -5 M) and dysfunctional arteries (7.8 x 10 -5 +/-14.6 x 10 -5 M). Nitroglycerine proved more potent than caffeine (EC 50 = 4.3 x 10 -9 +/-4.4 x 10 -9 M) ( p=0.013). CONCLUSIONS: Although nitroglycerin was a more potent vasodilator, caffeine had a strong arterial vasodilator effect regardless of endothelial function in human arteries.

Acción in vitro de la cafeína en anillos de arteria mamaria interna utilizada en cirugía de revascularización cardiaca / In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery

Introducción. El efecto vasodilatador de la cafeína en las arterias de modelos animales ya ha sido demostrado. Se desconocen estudios con la misma metodología in vitro utilizando arterias humanas. Objetivos. Evaluar los efectos vasoactivos in vitro de la cafeína en la arteria mamaria interna de humanos. Materiales y métodos. Se utilizaron 80 anillos de arteria mamaria interna (n=20 pacientes). La funcionalidad del endotelio se evaluó con acetilcolina a una concentración de 3,16x10 -6 M, de nitroglicerina con dosis acumulativas de 10 –11 M a 10 –4 M y de cafeína con concentraciones acumulativas de 10 –8 M a 10 –4 M. Resultados. La nitroglicerina indujo un porcentaje máximo de relajación de 87,4±12,3 por ciento, la cafeína, de 86,9±21,0 por ciento en arterias con endotelio funcional y de 71,6±28,6 por ciento en arterias con disfunción endotelial. No se encontraron diferencias entre los tres grupos ( p=0,289). Tampoco se encontraron diferencias en la EC 50 en arterias con endotelio funcional (1,66x10 -5 ±1,57x10 -5 M) y arterias disfuncionales (7,75x10 -5 ±14,64x10 -5 M). La nitroglicerina resultó más potente que la cafeína (EC 50 = 4,30x10 -9 ±4,35x10 -9 M) ( p=0,013). Conclusiones. Aunque la nitroglicerina fue un vasodilatador más potente, la cafeína tuvo un fuerte efecto vasodilatador arterial in vitro independientemente de la funcionalidad del endotelio en arterias humanas.

Comparación de anestesia espinal versus bloqueo nervioso ciático-femoral en pacientes ambulatorios sometidos a cirugía artroscópica de rodilla / Comparison of spinal anesthesia versus nervous sciatic - femoral blockade in ambulatory patients submitted to surgery artroscópica of knee

Se ha sugerido que la anestesia regional posee efectos benéficos en cirugía ambulatoria resultando en mejor analgesia, superior satisfacción del paciente y disminución de la utilización de recursos. El objetivo del presente estudio fue comparar dos técnicas anestésicas regionales en relación con la preparación para cirugía y la recuperación de los pacientes, en una población ambulatoria estandarizada. Métodos: Se estudiaron 50 pacientes adultos, ASA I-II, sometidos a cirugía artroscópica de rodilla. Los sujetos se dividieron aleatoriamente en grupo espinal (n = 25) y grupo ciático-femoral (n=25). Pacientes del grupo espinal recibieron anestesia subaracnoidea con 7.5 mg de bupivacaina hiperbárica. Pacientes del grupo ciáticofemoral recibieron bloqueo nervioso ciático-femoral utilizando una mezcla de 20 mL de lidocaina al 2 por cien más 20 mL de bupivacaina al 0.5 por cien. Se registraron los tiempos desde el ingreso a salas de cirugía hasta el comienzo de la misma, duración del procedimiento quirúrgico, tiempos de recuperación, satisfacción del paciente, calidad de la analgesia y ocurrencia de efectos adversos. Resultados: No se encontraron diferencias significativas en las medidas de recuperación entre los dos grupos. Luego de la salida del hospital el dolor difirió significativamente a las 6 horas post-operatorias (P = 0.002). La satisfacción fue alta con ambas técnicas. Conclusiones: En pacientes sometidos ambulatoriamente a cirugía artroscópica de rodilla la utilización de bloqueo nervioso ciático-femoral ofrece anestesia satisfactoria con un perfil clínico similar al obtenido con anestesia espinal a bajas dosis. Sin embargo, el bloqueo ciático-femoral se asocia significativamente con menos dolor durante las primeras 6 horas post-operatorias.

The vasodilatory effects of levosimendan on the human internal mammary artery.

BACKGROUND: Levosimendan, an inotropic drug that enhances myocardial contractility through myofilment calcium sensitazion, induces peripheral vasodilation via opening ATP-dependent K(+) channels. It is unknown whether this drug can be used for the treatment of perioperative vasospasm of arterial conduits used for coronary artery bypass grafting. METHODS: We investigated the effects of levosimendan on human internal mammary artery (IMA) specimens taken from patients undergoing coronary artery bypass surgery. The rings were carefully prepared and placed between two wire hooks in organ bath chambers and then constricted submaximally with norepinephrine and thromboxane A(2) analog (U46619). Nitroglycerin, milrinone, and levosimendan were separately added in a cumulative fashion and concentration response curves for relaxation were constructed. In parallel experiments, the response to levosimendan was evaluated on rings with and without functional endothelium. Levosimendan prevention of norepinephrine-induced contraction was also estimated. RESULTS: Nitroglycerin, milrinone, and levosimendan completely reversed the contraction of the IMA segments induced by U46619 and norepinephrine. Levosimendan produced a potent, concentration-dependent preventive effect on the norepinephrine-induced contraction of IMA. The responses to levosimendan were similar in preparations with or without endothelium.

Efectos pleiotrópicos de las estatinas. Características farmacológicas útiles en la prevención, tratamiento y regresión de la enfermedad cardiovascular / Pleiotropic effect of statins. Useful pharmacological characteristics in prevention, treatment and regression of cardiovascular disease

Los resultados benéficos de las estatinas en el manejo de la hipercolesterolemia en los múltiples estudios clínicos, han demostrado, además, efectos no relacionados con la acción hipolipemiante. Estudios experimentales in-vitro y ex-vivo han documentado una gran evidencia de efectos tales como incremento en la expresión de óxido nítrico y efectos anti-inflamatorios, inmunomodulatorios, anti-trombóticos, anti-proliferativos y anti-oxidantes los cuales reciben el nombre de pleiotrópicos. Los potentes efectos hipolipemiantes y pleiotrópicos podrían explicar los beneficios en aterosclerosis, hipertensión arterial, diabetes mellitus, estenosis aórtica, psoriasis, esclerosis múltiple y rechazo post-transplante entre otras patologías. Sin embargo, la cantidad de información experimental a favor de estos efectos, debería estimular a la iniciación de mejores estudios para clarificar de una manera mayor el significado clínico.

¿Podría tener la cafeína algún efecto vasculoprotector? / Could caffeine have some vasoprotective effect?

El café es la bebida estimulante caliente de mayor consumo en el mundo y hace parte de la dieta corriente y cultural de nuestra sociedad. Existe un ®mito¼ alrededor del café, considerándolo nocivo con base en estudios clínicos, cuyos resultados han sido contradictorios y sin un sustento científico sólido. Sólo en los últimos años, se han venido describiendo las bondades del café a nivel cognoscitivo, digestivo y cardiovascular.Se presenta el efecto vasodilatador de la cafeína en un modelo experimental in-vitro que utiliza anillos de aorta procedentes de conejos sanos, colocados en un baño de órganos de 4 canales (Kent Scientific Corporation, Litchfield CT), en solución de Krebs, a 37°C, pH 7.40 +/- 0.05 y aireada con O2 95 porciento y CO2 5 porciento. Los anillos fueron pre-contraídos con norepinefrina (- 5.5 Log M) y relajados con nitroglicerina (relajación independiente de endotelio), acetilcolina (relajación dependiente de endotelio) y cafeína.

Off-pump versus on-pump coronary artery bypass surgery and postoperative pulmonary dysfunction.

OBJECTIVE: To investigate how off-pump coronary artery bypass grafting (CABG) affects postoperative pulmonary function when compared with on-pump CABG. DESIGN: Prospective clinical study. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Adult patients (n = 39) undergoing elective coronary artery bypass surgery with or without cardiopulmonary bypass. INTERVENTIONS: Two groups of patients were compared: 19 consecutive patients undergoing off-pump CABG surgery and 20 consecutive patients undergoing conventional CABG surgery. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests (flow volume loops and lung volumes with plethysmography) were done preoperatively and 72 hours postoperatively. Arterial blood gases and PaO2/FIO2 were measured at various stages. Sequential chest x-rays were obtained and evaluated for pleural changes, pulmonary edema, and atelectasis. In both groups, PaO2/FIO2 ratios decreased progressively throughout the perioperative period, with no significant differences between the groups at any stage during the study. There was a significant decline in postoperative pulmonary function tests in both groups, but there was no difference between groups at 72 hours postoperatively. No differences were found in the time to extubation, atelectasis scores, or postoperative complications. CONCLUSIONS: Off-pump CABG does not confer major protection from postoperative pulmonary dysfunction compared with CABG surgery with CPB. Strategies for minimizing pulmonary impairment after CABG surgery should be directed to factors other than the use of CPB.