B Chromosomes in Psalidodon scabripinnis (Characiformes, Characidae) Species Complex.

B chromosomes are extra-genomic components of cells found in individuals and in populations of some eukaryotic organisms. They have been described since the first observations of chromosomes, but several aspects of their biology remain enigmatic. Despite being present in hundreds of fungi, plants, and animal species, only a small number of B chromosomes have been investigated through high-throughput analyses, revealing the remarkable mechanisms employed by these elements to ensure their maintenance. Populations of the Psalidodon scabripinnis species complex exhibit great B chromosome diversity, making them a useful material for various analyses. In recent years, important aspects of their biology have been revealed. Here, we review these studies presenting a comprehensive view of the B chromosomes in the P. scabripinnis complex and a new hypothesis regarding the role of the B chromosome in the speciation process.

Piezometric level and electrical conductivity spatiotemporal monitoring as an instrument to design further managed aquifer recharge strategies in a complex estuarial system under anthropogenic pressure.

Recife Metropolitan Region (RMR, NE Brazil) lies over a multi-layered aquifer system located in an estuarial area. The region has experienced fast population growth and repeated droughts in the last three decades, which led to unprecedented anthropogenic pressure on groundwater resources because of intense water pumping. Accordingly, scientific and stakeholder communities have been challenged to ensure the maintenance of sustainable groundwater resource by managing all water cycle. Because controlling pumping rates is difficult due to the large number of illegal wells, the Managed Aquifer Recharge (MAR) strategies are now under consideration. The RMR presents a tropical climate and an annual average rainfall rate of approximately 2450 mm year-1, providing great potential volumes of water to be used for piezometric level recovery. However, MAR implementation requires a detailed and in-depth knowledge of the human-impact on the hydrogeological behavior of the resource over the long-term, in order to find out the most appropriate recharge strategy. Therefore, the present study illustrates how routine data monitoring, i.e., piezometric level and electrical conductivity (EC), in combination with the geological knowledge, may allow proposing further MAR strategies. Two contrasted behaviors were observed in RMR: (i) groundwater level decrease and stable EC in the North and Southernmost areas of Recife; and (ii) stable groundwater level and high/varying EC values next to the estuarial zone. Although aquifers are undergoing over-abstraction, this spatiotemporal heterogeneity suggests that a recharge is possibly locally favored next to the estuarial area of the RMR thanks to hydraulic connections between surface and deep aquifers throughout extended paleo-channels. Thus, based on this typology, MAR implementation through controlled infiltration close to the estuarial area seems to be more appropriated, whereas the direct deep injection appears to be more relevant in more distant zones.

Management of splenic and pancreatic trauma.

The spleen and pancreas are at risk for injury during abdominal trauma. The spleen is more commonly injured because of its fragile structure and its position immediately beneath the ribs. Injury to the more deeply placed pancreas is classically characterized by discordance between the severity of pancreatic injury and its initial clinical expression. For the patient who presents with hemorrhagic shock and ultrasound evidence of major hemoperitoneum, urgent "damage control" laparotomy is essential; if splenic injury is the cause, prompt "hemostatic" splenectomy should be performed. Direct pancreatic injury is rarely the cause of major hemorrhage unless a major neighboring vessel is injured, but if there is destruction of the pancreatic head, a two-stage pancreatoduodenectomy (PD) may be indicated. At open laparotomy when the patient's hemodynamic status can be stabilized, it may be possible to control splenic bleeding without splenectomy; it is always essential to search for injury to the pancreatic duct and/or the adjacent duodenum. Pancreatic contusion without ductal rupture is usually treated by drain placement adjacent to the injury; ductal injuries of the pancreatic body or tail are treated by resection (distal pancreatectomy with or without splenectomy), with generally benign consequences. For injuries of the pancreatic head with pancreatic duct disruption, wide drainage is usually performed because emergency PD is a complex gesture prone to poor results. Postoperatively, the placement of a ductal stent by endoscopic retrograde catheterization may be decided, while management of an isolated pancreatic fistula is often straightforward. Non-operative management is the rule for the trauma victim who is hemodynamically stable. In addition to the clinical examination and conventional laboratory tests, investigations should include an abdominothoracic CT scan with contrast injection, allowing identification of all traumatized organs and assessment of the severity of injury. In this context, non-operative management (NOM) has gradually become the standard as long as the patient remains hemodynamically stable and there is no suspicion of injury to hollow viscera, with the patient being carefully monitored on a surgical service. The development of arteriography with splenic artery embolization has increased the rate of splenic salvage; this can be performed electively based on specific indications (blush on CT, pseudoaneurysm, arteriovenous fistula), and may also be considered for severe splenic injury, abundant hemoperitoneum, or severe polytrauma. For pancreatic injury, in addition to CT scan, magnetic resonance pancreatography (MRCP) or even endoscopic retrograde cholangiopancreatography (ERCP) may be necessary to identify a ductal rupture. If the pancreatic duct is intact, laboratory and CT imaging surveillance is performed just as for splenic injury. In case of pancreatic ductal injury, ERCP stenting can be considered. However, if this is unsuccessful, the therapeutic decision can be difficult: while NOM can still be successful, complications may arise that are difficult to treat while distal pancreatectomy, although initially more agressive may avoid these complications if performed early.

Axillary artery in cardiopulmonary bypass: indications and results.

OBJECTIVES: To determine indications and results of axillary artery cannulation for cardiopulmonary bypass. METHODS: From January 2005 through December 2008, axillary artery cannulation was used in 48 patients. Mean age was 62 +/- 11 years and 33 (69%) patients were males. Axillary artery was approached by infraclavicular incision and the cannula introduced in a 8 millimeter Dacron side graft. RESULTS: Indications were calcified aorta (N=18, 38%), aortic dissection (N=15, 31%), ascending and/or aortic arch aneurysm (N=11, 23%) and prior to reoperative median sternotomy (N=4, 8%). Changes in intraoperative planning occurred most often in patients with calcified aorta (100% versus 10%, P<0.0001) than in patients with other indications, which follow their preoperative plan. Cardiopulmonary bypass (deep hypothermic circulatory arrest in 55% and conventional in the remaining) was uneventfully conducted in all patients but one (success rate 98%) due to undiagnosed inominate artery stenosis. Local complication was lymphatic drainage in three (6.2%) patients. CONCLUSIONS: Axillary artery is an alternative cannulation site in patients unsuitable to aortic cannulation. The type of indication may determine intraoperative changes in surgical planning.

Results of the establishment of an organizational model in a cardiovascular surgery service.

OBJECTIVE: Increasing complexity of patients referred to cardiac surgery demands more effective heart centers, in order to maintain the same quality. The aim of this study is to examine the short-term effect of adoption of an organizational model on surgical outcomes. METHODS: From January 2006 to June 2007, 367 consecutive adult patients underwent cardiovascular surgery. Pre-, intra- and postoperative data were prospectively collected and transferred to an institutional database. Organizational model was established in August 2006, and based on integrated multiprofessional team work patient-centered, evidence-based medicine with standardized patient care and personal conflict management. The outcomes studied were hospital mortality and combined adverse events (death, stroke, acute myocardial infarction and acute renal failure), by using multivariate logistic regression analysis. RESULTS: After establishment of such model, there was reduction of hospital mortality (from 12% to 3.6%, relative risk= 0.3; P=0.003) and combined events (from 22% to 15%, relative risk=0.68; P=0.11). Operations performed previously to the model were independently associated with higher mortality (OR=2.5; P=0.04), adjusted to preoperative characteristics and Euroscore risk stratification system. Other predictors of mortality were age > 65 years (OR=6.36; 95%CI 2.57 - 17.21; P<0.0001) and cardiopulmonary bypass time > 145 minutes (OR=8.57; 95%CI 3.55 - 21.99; P<0.0001). CONCLUSION: Marked improvements in surgical outcomes depend on development of cardiac surgery centers based on organizational models similar to the model proposed in this study.

Artéria axilar na instalação de circulação extracorpórea: indicações e resultados / Axillary artery in cardiopulmonary bypass: indications and results

OBJETIVO: Estudar as indicações e os resultados da artéria axilar na instalação de circulação extracorpórea. MÉTODOS: Entre janeiro de 2005 e dezembro de 2008, a artéria axilar foi utilizada em 48 pacientes submetidos a cirurgia cardiovascular. A idade média foi 62 ± 11 anos e 33 (69 por cento) pacientes eram do sexo masculino. A artéria axilar foi abordada por incisão infraclavicular e a cânula introduzida no tubo de Dacron de 8 milímetros suturado nos bordos da artéria. RESULTADOS: As indicações foram calcificação da aorta (N=18, 38 por cento), dissecção da aorta (N=15, 31 por cento), aneurisma da aorta ascendente e/ou arco aórtico (N=11, 23 por cento) e prévio a reesternotomia (N=4, 8 por cento). A presença de calcificação da aorta levou mais frequentemente à mudança de tática intra-operatória do que as outras indicações (100 por cento versus 10 por cento, P<0,0001) que seguiram o planejamento cirúrgico pré-operatório. A condução da circulação extracorpórea (parada circulatória total em 55 por cento e convencional no restante) transcorreu sem problemas em todos os casos, exceto um (taxa de sucesso de 98 por cento) em decorrência de estenose do tronco braquiocefálico não diagnosticada previamente. Complicação local se limitou a linfocele em três (6,2 por cento) pacientes. CONCLUSÕES: A artéria axilar é uma alternativa à impossibilidade de canulação da aorta ascendente na instalação de circulação extracorpórea. O tipo de indicação do uso da artéria axilar pode determinar mudanças intra-operatórias do planejamento cirúrgico

OBJECTIVES: To determine indications and results of axillary artery cannulation for cardiopulmonary bypass. METHODS: From January 2005 through December 2008, axillary artery cannulation was used in 48 patients. Mean age was 62 ± 11 years and 33 (69 percent) patients were males. Axillary artery was approached by infraclavicular incision and the cannula introduced in a 8 millimeter Dacron side graft. RESULTS: Indications were calcified aorta (N=18, 38 percent), aortic dissection (N=15, 31 percent), ascending and/or aortic arch aneurysm (N=11, 23 percent) and prior to reoperative median sternotomy (N=4, 8 percent). Changes in intraoperative planning occurred most often in patients with calcified aorta (100 percent versus 10 percent, P<0.0001) than in patients with other indications, which follow their preoperative plan. Cardiopulmonary bypass (deep hypothermic circulatory arrest in 55 percent and conventional in the remaining) was uneventfully conducted in all patients but one (success rate 98 percent) due to undiagnosed inominate artery stenosis. Local complication was lymphatic drainage in three (6.2 percent) patients. CONCLUSIONS: Axillary artery is an alternative cannulation site in patients unsuitable to aortic cannulation. The type of indication may determine intraoperative changes in surgical planning

Resultados da implementação de modelo organizacional de um serviço de cirurgia cardiovascular / Results of the establishment of an organizational model in a cardiovascular surgery service

OBJETIVO: A crescente complexidade de pacientes encaminhados a cirurgia cardíaca exige maior eficiência dos serviços que prestam assistência, no sentido de manter a mesma qualidade. O objetivo é examinar o impacto, em curto prazo, da adoção de um modelo organizacional nos resultados cirúrgicos. MÉTODOS: No período entre janeiro de 2006 a junho de 2007, 367 pacientes adultos consecutivos foram submetidos à cirurgia cardiovascular. Os dados pré, intra e pós-operatórios foram colhidos prospectivamente e armazenados em um banco de dados institucional. Modelo organizacional foi implementado em agosto de 2006 e se baseou em trabalho multiprofissional integrado centralizado no paciente, medicina baseada em evidências com condutas padronizadas e resolução de conflitos interpessoais. Os desfechos estudados foram mortalidade hospitalar e eventos combinados (óbito, acidente vascular cerebral, infarto agudo do miocárdio e insuficiência renal aguda), por meio de regressão logística multivariada. RESULTADOS: Após a adoção do modelo, houve redução da mortalidade hospitalar (de 12 por cento para 3,6 por cento, risco relativo= 0,3; P=0,003) e de eventos combinados (de 22 por cento para 15 por cento, risco relativo= 0,68; P=0,11). Operações realizadas anteriormente à implementação do modelo estiveram associadas independentemente com maior mortalidade (OR=2,5; P=0,04), ajustada para características préoperatórias e complexidade pelo EuroSCORE. Outros preditores de mortalidade foram idade > 65 anos (OR=6,36; IC95 por cento 2,57 - 17,21; P<0,0001) e o tempo de circulação extracorpórea > 145 minutos (OR=8,57; IC95 por cento 3,55 - 21,99; P<0,0001). CONCLUSÃO: A rápida melhora dos resultados cirúrgicos depende da composição de serviços de cirurgia cardíaca embasados em modelos organizacionais semelhantes ao proposto.

OBJECTIVE: Increasing complexity of patients referred to cardiac surgery demands more effective heart centers, in order to maintain the same quality. The aim of this study is to examine the short-term effect of adoption of an organizational model on surgical outcomes. METHODS: From January 2006 to June 2007, 367 consecutive adult patients underwent cardiovascular surgery. Pre-, intra- and postoperative data were prospectively collected and transferred to an institutional database. Organizational model was established in August 2006, and based on integrated multiprofessional team work patient-centered, evidence-based medicine with standardized patient care and personal conflict management. The outcomes studied were hospital mortality and combined adverse events (death, stroke, acute myocardial infarction and acute renal failure), by using multivariate logistic regression analysis. RESULTS: After establishment of such model, there was reduction of hospital mortality (from 12 percent to 3.6 percent, relative risk= 0.3; P=0.003) and combined events (from 22 percent to 15 percent, relative risk=0.68; P=0.11). Operations performed previously to the model were independently associated with higher mortality (OR=2.5; P=0.04), adjusted to preoperative characteristics and Euroscore risk stratification system. Other predictors of mortality were age > 65 years (OR=6.36; 95 percentCI 2.57 - 17.21; P<0.0001) and cardiopulmonary bypass time > 145 minutes (OR=8.57; 95 percentCI 3.55 - 21.99; P<0.0001). CONCLUSION: Marked improvements in surgical outcomes depend on development of cardiac surgery centers based on organizational models similar to the model proposed in this study.

Inspiratory resistive loading after all-out exercise improves subsequent performance.

We have previously shown that post-exercise inspiratory resistive loading (IRL) reduces blood lactate ([Lac(b)(-)]). In this study, we tested the hypothesis that IRL during recovery could improve subsequent exercise performance. Eight healthy men underwent, on different days, two sequential 30-s, cycle ergometer Wingate tests. During the 10-min recovery period from test 1, subjects breathed freely or through an inspiratory resistance (15 cm H(2)O) with passive leg recovery. Arterialized [Lac(b)(-)] values, perceptual scores (Borg), cardiac output by impedance cardiography (QT), and changes in the deoxygenation status of the M. vastus lateralis by near-infrared spectroscopy (DeltaHHb), were recorded. [Lac(b)(-)] was significantly reduced after 4 min of recovery with IRL (peak [Lac(b)(-)] 12.5 +/- 2.3 mmol l(-1) with free-breathing vs. 9.8 +/- 1.5 mmol l(-1) with IRL). Effort perception was reduced during late recovery with IRL compared with free-breathing. Cardiac work was increased with IRL, since heart rate and QT were elevated during late recovery. Peripheral muscle reoxygenation, however, was significantly impaired with IRL, suggesting that post-exercise convective O(2) delivery to the lower limbs was reduced. Importantly, IRL had a dual effect on subsequent performance, i.e., improvement in peak and mean power, but increased fatigue index (P < 0.05). Our data demonstrate that IRL after a Wingate test reduces post-exercise effort perception and improves peak power on subsequent all-out maximal-intensity exercise.

Recurrent ventricular arrhythmia after coronary artery bypass grafting treated with radiofrequency catheter ablation.

A 63-year-old diabetic woman was emergently submitted to coronary artery bypass grafting in the setting of acute myocardial infarction. Recurrent, drug-refractory episodes of ventricular arrhythmia occurred for 2 weeks postoperatively, despite no documentation of ongoing myocardial ischemia and optimum medical treatment. Ventricular arrhythmia was initiated by premature ventricular contractions originating from the Purkinje system within the infarct border zone. Radiofrequency catheter ablation was performed at sites where Purkinje potentials were recorded, leading to arrhythmia cessation. A week later, an implantable cardioverter defibrillator was inserted and she was discharged home a few days later. At 15-month follow-up, there were no further episodes of arrhythmia and ventricular function had improved.

Experiências matemáticas no contexto de jogos eletrônicos / Mathematics experiences in the context of electronic games

O presente trabalho aborda o desenvolvimento lógico-matemático de experiências imersivas em um ambiente digital oferecido dentro do game conceitual Myst – Riven e argumenta que atividades investigativas desenvolvidas com os “puzzles” de Myst podem incentivar uma atitude especulativa em matemática, capaz de fomentar uma concepção mais dinâmica da matemática e de sua produção do conhecimento. É postulado ainda o desenvolvimento de ambientes profícuos para aprendizagem matemática no qual o professor tem o papel de agenciador de experiências.

Involução de artérias colaterais aneurismáticas após a correção da coarctação da aorta / Involution of aneurysmal collateral arteries after correction of aortic coarctation

Paciente de 47 anos de idade, com diagnóstico de coarctação da aorta, foi submetido ao implante de tubo extra-anatômico por toracotomia esquerda. Dez anos após o procedimento, o paciente retorna com hipertensão arterial de difícil controle relacionada a coarctação da aorta residual, obstrução do tubo e múltiplos aneurismas de artérias colaterais entre a artéria subclávia e a aorta. O paciente foi submetido então a correção extra-anatômica entre a aorta ascendente e a descendente por esternotomia mediana, com auxílio de circulação extracorpórea convencional. Sua recuperação pós-operatória foi boa, e houve involução completa de todas as artérias colaterais aneurismáticas após a operação.

A 47 year-old man with aortic coarctation had undergone extra-anatomic bypass through a left thoracotomy. He presented 10 years later with uncontrolled arterial hypertension due to residual aortic coarctation, graft obstruction and multiple collateral artery aneurysms between the subclavian artery and the aorta. He underwent extra-anatomic correction between the ascending aorta to descending aorta through a median sternotomy with the aid of conventional cardiopulmonary bypass. His postoperative recovery was unremarkable, and there was complete involution of all aneurysmal collateral arteries after the operation.

Use of centrifugal pump and extracorporeal membrane oxygenation as cardiopulmonary support in pediatric cardiovascular surgery.

BACKGROUND: Extracorporeal membrane oxygenation is a well-documented resuscitation method in patients with severe hemodynamic and/or respiratory impairment. OBJECTIVE: To describe several aspects related to the use of extracorporeal membrane oxygenation in a pediatric heart center and determine its immediate and late outcomes. METHODS: Between October 2005 and January 2007, 10 patients who were submitted to pediatric cardiac surgery underwent extracorporeal membrane oxygenation implant. Median age was 58.5 days (40% neonates) and median body weight was 3.9 kg. Circulatory assistance was initiated aiming at the recovery and the weaning protocols followed daily clinical and echocardiographic criteria. Support was discontinued when transplant was contraindicated, when the patient was unable to recover or when survival was considered to be limited by a multidisciplinary team. RESULTS: Extracorporeal membrane oxygenation was employed after corrective or palliative heart surgery in 80% and preoperatively in the remaining ones. It was most often indicated for irresponsive hemodynamic instability (40%), post-cardiotomy shock (20%) and post-cardiac arrest (20%). The mean duration on support was 58 +/- 37 hours. Weaning was successfully in 50% of the cases and 30% were discharged home. Actuarial survival was 40%, 30% and 20% at 30 days, 3 months and 24 months, respectively. CONCLUSION: Extracorporeal membrane oxygenation is an effective and useful tool for the resuscitation of patients presenting severe hemodynamic and/or respiratory failure in the perioperative period of pediatric cardiovascular surgery.

Inspiratory muscle training improves blood flow to resting and exercising limbs in patients with chronic heart failure.

OBJECTIVES: We tested the hypothesis that inspiratory muscle loading could result in exaggerated peripheral vasoconstriction in resting and exercising limbs and that inspiratory muscle training (IMT) could attenuate this effect in patients with chronic heart failure (CHF) and inspiratory muscle weakness. BACKGROUND: Inspiratory muscle training improves functional capacity of patients with CHF, but the mechanisms of this effect are unknown. METHODS: Eighteen patients with CHF and inspiratory muscle weakness (maximal inspiratory pressure <70% of predicted) and 10 healthy volunteers participated in the study. Inspiratory muscle loading was induced by the addition of inspiratory resistance of 60% of maximal inspiratory pressure, while blood flow to the resting calf (CBF) and exercising forearm (FBF) were measured by venous occlusion plethysmography. For the patients with CHF, blood flow measurements as well as ultrasound determination of diaphragm thickness were made before and after a 4-week program of IMT. RESULTS: With inspiratory muscle loading, CHF patients demonstrated a more marked reduction in resting CBF and showed an attenuated rise in exercising FBF when compared with control subjects. After 4 weeks of IMT, CHF patients presented hypertrophy of the diaphragm and improved resting CBF and exercise FBF with inspiratory muscle loading. CONCLUSIONS: In patients with CHF and inspiratory muscle weakness, inspiratory muscle loading results in marked reduction of blood flow to resting and exercising limbs. Inspiratory muscle training improves limb blood flow under inspiratory loading in these patients.

Thyroid hormone action is required for normal cone opsin expression during mouse retinal development.

PURPOSE: The expression of S- and M-opsins in the murine retina is altered in different transgenic mouse models with mutations in the thyroid hormone receptor (TR)-beta gene, demonstrating an important role of thyroid hormone (TH) in retinal development. METHODS: The spatial expression of S- and M-opsin was compared in congenital hypothyroidism and in two different TR mutant mouse models. One mouse model contains a ligand-binding mutation that abolishes TH binding and results in constitutive binding to nuclear corepressors. The second model contains a mutation that blocks binding of coactivators to the AF-2 domain without affecting TH binding. RESULTS: Hypothyroid newborn mice showed an increase in S-opsin expression that was completely independent of the genotype. Concerning M-opsin expression, hypothyroidism caused a significant decrease (P < 0.01) only in wild-type animals. When TRbeta1 and -beta2 were T3-binding defective, the pattern of opsin expression was similar to TRbeta ablation, showing increased S-opsin expression in the dorsal retina and no expression of M-opsin in the entire retina. In an unexpected finding, immunostaining for both opsins was detected when both subtypes of TRbeta were mutated in the helix 12 AF-2 domain. CONCLUSIONS: The results show, for the first time, that the expression of S- and M-opsin is dependent on normal thyroid hormone levels during development.

Emprego do suporte cardiopulmonar com bomba centrífuga e oxigenador de membrana em cirurgia cardiovascular pediátrica / Use of centrifugal pump and extracorporeal membrane oxygenation as cardiopulmonary support in pediatric cardiovascular surgery

FUNDAMENTO: O suporte cardiopulmonar com oxigenador de membrana é um método de ressuscitação de distúrbios hemodinâmicos, pulmonares ou ambos, consagrado em centros internacionais. OBJETIVOS: Descrever diversos aspectos relacionados ao suporte cardiopulmonar com oxigenador de membrana em um serviço de cirurgia cardiovascular nacional e determinar seus resultados imediatos e tardios. MÉTODOS: Entre outubro de 2005 e janeiro de 2007, 10 pacientes foram submetidos a suporte circulatório e/ou respiratório em candidatos ou submetidos a cirurgia cardiovascular pediátrica, com idade mediana de 58,5 dias (40 por cento de neonatos) e peso mediano de 3,9 kg. O suporte foi mantido com a intenção de recuperação e desmame, de acordo com critérios clínicos e ecocardiográficos diários. O suporte foi descontinuado nos pacientes sem indicação de transplante, com incapacidade de recuperação e com sobrevida limitada, de acordo com julgamento multidisciplinar. RESULTADOS: O suporte circulatório foi utilizado no pós-operatório de operações corretivas ou paliativas em 80 por cento e no pré-operatório no restante. Instabilidade hemodinâmica grave irresponsiva (40 por cento), falência miocárdica na saída de circulação extracorpórea (20 por cento) e parada cardíaca no pós-operatório (20 por cento) foram as indicações mais freqüentes. O tempo médio de permanência em suporte circulatório foi de 58 ± 37 horas. O suporte foi retirado com sucesso em 50 por cento e 30 por cento obtiveram alta hospitalar. A sobrevida atuarial foi de 40 por cento, 30 por cento e 20 por cento aos 30 dias, 3 meses e 24 meses, respectivamente. CONCLUSÃO: O suporte cardiopulmonar com oxigenador de membrana foi um método eficaz e útil na ressuscitação de distúrbios cardiovasculares e pulmonares graves no perioperatório de cirurgia cardiovascular pediátrica.

BACKGROUND: Extracorporeal membrane oxygenation is a well-documented resuscitation method in patients with severe hemodynamic and/or respiratory impairment. OBJECTIVE: To describe several aspects related to the use of extracorporeal membrane oxygenation in a pediatric heart center and determine its immediate and late outcomes. METHODS: Between October 2005 and January 2007, 10 patients who were submitted to pediatric cardiac surgery underwent extracorporeal membrane oxygenation implant. Median age was 58.5 days (40 percent neonates) and median body weight was 3.9 kg. Circulatory assistance was initiated aiming at the recovery and the weaning protocols followed daily clinical and echocardiographic criteria. Support was discontinued when transplant was contraindicated, when the patient was unable to recover or when survival was considered to be limited by a multidisciplinary team. RESULTS: Extracorporeal membrane oxygenation was employed after corrective or palliative heart surgery in 80 percent and preoperatively in the remaining ones. It was most often indicated for irresponsive hemodynamic instability (40 percent), post-cardiotomy shock (20 percent) and post-cardiac arrest (20 percent). The mean duration on support was 58 ± 37 hours. Weaning was successfully in 50 percent of the cases and 30 percent were discharged home. Actuarial survival was 40 percent, 30 percent and 20 percent at 30 days, 3 months and 24 months, respectively. CONCLUSION: Extracorporeal membrane oxygenation is an effective and useful tool for the resuscitation of patients presenting severe hemodynamic and/or respiratory failure in the perioperative period of pediatric cardiovascular surgery.

Blood lactate during recovery from intense exercise: impact of inspiratory loading.

PURPOSE: It has long been suggested that inspiratory muscle activity may impact blood lactate levels ([Lac(-)]B) during the recovery from dynamic exercise. In this study, we tested the hypothesis that inspiratory muscle activation during recovery from intense exercise would contribute to La clearance, thus leading to reduced [Lac(-)]B. METHODS: Twelve healthy men underwent two maximal, incremental exercise tests on different days. During a 20-min inactive recovery period, they breathed freely or against a fixed inspiratory resistance of 15 cm H2O. During recovery, pulmonary gas exchange was continuously monitored, and serial samples of arterialized venous blood were obtained for [Lac(-)]B, pH, PCO2, and HCO3(-). RESULTS: Subjects presented similar ventilatory and gas-exchange responses at peak exercise during both experimental conditions. [Lac(-)]B during recovery was reduced with inspiratory resistance (7.7 +/- 1 vs 10.4 +/- 1, 7.8 +/- 2 vs 10.3 +/- 2, and 7.3 +/- 1 vs 9.7 +/- 2 mM at 5, 7, and 9 min of recovery, respectively; P < 0.05), but no differences were found for blood acid-base status. Inspiratory resistance was associated with increased metabolic demand (V O2 and V CO2) but improved ventilatory efficiency, with lower V E/[V CO2] and increased alveolar ventilation. CONCLUSION: These data are consistent with the notion that inspiratory muscles may be net consumers of lactate during recovery from intense exercise.

Attenuation of muscle metaboreflex in chronic obstructive pulmonary disease.

PURPOSE: Abnormal skeletal muscle function is well documented in chronic obstructive pulmonary disease, but there is no information about the activity of muscle metabosensitive afferents. In this study, we tested the hypothesis that patients with chronic obstructive pulmonary disease would have abnormal reflex responses to stimulation of metabosensitive afferents in skeletal muscle when compared with healthy, matched subjects. METHODS: In 16 patients with moderate to severe chronic obstructive pulmonary disease and 13 healthy, age-matched control subjects, we evaluated heart rate, mean blood pressure, calf blood flow, and calf vascular resistance responses to static handgrip exercise at 30% of maximal voluntary contraction, followed by recovery with or without circulatory occlusion. Muscle metaboreflex control of calf vascular resistance was estimated by subtracting the area under the curve with circulatory occlusion from the area under the curve without circulatory occlusion. RESULTS: Mean blood pressure and heart rate responses were not significantly different in patients and controls during exercise and recovery. In the control group, calf vascular resistance increased significantly during exercise and remained elevated above baseline during circulatory occlusion, whereas in patients changes from rest were not significantly different in both trials. Estimated muscle metaboreflex control of calf vascular resistance was significantly reduced in the patients (controls: 31 +/- 22 units, patients: 8 +/- 31 units, P < 0.05). CONCLUSION: Patients with chronic obstructive pulmonary disease have a reduced calf vascular resistance response to handgrip exercise and to selective activation of muscle metaboreflex when compared with healthy subjects.

Combined complex open heart surgery and infra-renal aortic aneurysm repair.

The optimal management of patients with combined ischemic and/or valvular heart disease and abdominal aortic aneurysm is still a matter of debate. A 60-year-old woman presented with a large infra-renal aortic aneurysm. Preoperative workup revealed ischemic cardiomyopathy and aortic regurgitation. She was submitted to one-stage aneurysm repair and complex heart surgery. Postoperatively, she developed mediastinal bleeding, transient renal dysfunction, pulmonary edema and superficial wound infection. She was discharged home about a month later without residual problems.

Involution of aneurysmal collateral arteries after correction of aortic coarctation.

A 47 year-old man with aortic coarctation had undergone extra-anatomic bypass through a left thoracotomy. He presented 10 years later with uncontrolled arterial hypertension due to residual aortic coarctation, graft obstruction and multiple collateral artery aneurysms between the subclavian artery and the aorta. He underwent extra-anatomic correction between the ascending aorta to descending aorta through a median sternotomy with the aid of conventional cardiopulmonary bypass. His postoperative recovery was unremarkable, and there was complete involution of all aneurysmal collateral arteries after the operation.

Muscle metaboreflex contribution to resting limb haemodynamic control is preserved in older subjects.

Ageing is associated with tonic elevations in basal sympathetic vasoconstrictor outflow to skeletal muscle and a parallel decline in vascular function. The purpose of this study was to test the hypothesis that older individuals exhibit attenuated calf vascular resistance (CVR) responses to muscle metaboreflex activation in comparison with young subjects. Fourteen young (mean +/- SD age 23 +/- 3 years) and 13 older (62 +/- 7 years) sedentary subjects participated in the study. To evaluate muscle metaboreflex, we measured heart rate, mean blood pressure (MBP), calf blood flow (CBF) (venous occlusion plethysmography) and CVR responses to static handgrip exercise at 30% of maximal voluntary contraction, followed by recovery with [postexercise circulatory occlusion, (PECO+)] or without (PECO-) circulatory occlusion. Mean BP and CVR increased significantly (ANOVA P<0.05) throughout exercise and remained elevated during PECO+ when compared with PECO- in both groups. There were no significant differences between the two groups in BP and CVR relative changes from baseline during the entire protocol in both trials. CBF responses were also similar in the young and older subjects, except for the first minute of exercise, where young subjects had higher CBF responses. Our results demonstrate that older subjects have similar BP and calf haemodynamic responses to static handgrip exercise and selective action of the muscle metaboreflex when compared with young subjects, compatible with preserved muscle metaboreflex contribution to resting limb haemodynamic control with ageing in humans.