Derivation and validation of a national multicenter mortality risk stratification model - the ExCare model: a study protocol.

INTRODUCTION: Surgical care is essential for proper management of various diseases. However, it can result in unfavorable outcomes. In order to identify patients at higher risk of complications, several risk stratification models have been developed. Ideally, these tools should be simple, reproducible, accurate, and externally validated. Unfortunately, none of the best-known risk stratification instruments have been validated in Brazil. In this sense, the Ex-Care model was developed by retrospective data analysis of surgical patients in a major Brazilian university hospital. It consists of four independent predictors easily collected in the preoperative evaluation, showing high accuracy in predicting death within 30 days after surgery. OBJECTIVES: To update and validate a Brazilian national-based model of postoperative death probability within 30 days based on the Ex-Care model. Also, to develop an application for smartphones that allows preoperative risk stratification by Ex-Care model. METHODS: Ten participating centers will collect retrospective data from digital databases. Variables age, American Society of Anesthesiologists (ASA) physical status, surgical severity (major or non-major) and nature (elective or urgent) will be evaluated as predictors for in-hospital mortality within 30 postoperative days, considered the primary outcome. EXPECTED RESULTS: We believe that the Ex-Care model will present discriminative capacity similar to other classically used scores validated for surgical mortality prediction. Furthermore, the mobile application to be developed will provide a practical and easy-to-use tool to the professionals enrolled in perioperative care.

Chronic cholinergic stimulation promotes changes in cardiovascular autonomic control in spontaneously hypertensive rats.

Hypertension is often accompanied by autonomic dysfunction, which is detrimental to cardiac regulation. On the other hand, cholinergic stimulation through inhibition of acetylcholinesterase appears to have beneficial effects on cardiac autonomic control. Thus, our objective was to investigate the effects of chronic cholinergic stimulation on hemodynamic and cardiovascular autonomic control parameters in spontaneously hypertensive rats (SHR). For this, 26-week-old SHR (N = 32) and Wistar Kyoto rats (WK; N = 32) were divided into two groups: one treated with vehicle (H2O; N = 16) and the other treated with pyridostigmine bromide (PYR; N = 16) in drinking water (25 mg/kg/day) for 2 weeks. All groups were subjected to recording of arterial pressure (AP) and heart rate (HR), quantification of ejection fraction (EF), evaluation of cardiac tonic autonomic balance by means of double autonomic blockade with methylatropine and propranolol, analysis of systolic AP (SAP) and HR variability (HRV), and evaluation of baroreflex sensitivity (BRS). AP, HR, and EF were reduced in the SHR-PYR group compared with the SHR-H2O group. Evaluation of autonomic parameters revealed an increase in vagal tone participation in cardiac tonic autonomic balance and reduced SAP variability; however, no changes were observed in HRV or BRS. These results suggest that chronic cholinergic stimulation with pyridostigmine bromide promotes reduction in the hemodynamic parameters AP, HR, and EF. Additionally, tonic autonomic balance was improved and a reduction in LF oscillations of SAP variability was observed that could not be attributed to BRS, as the latter did not change. Further studies should be conducted to identify the mechanisms involved in the observed responses.

Efeito da tração manual sobre o comprimento da coluna cervical em indivíduos assintomáticos: estudo randomizado controlado / The effect of manual traction on the length of cervical spine in asymptomatic individuals: a randomized controlled study

Os objetivos do estudo foram o de mensurar o comprimento da coluna cervical quando submetida à tração manual, e o de verificar as alterações da cervical após um período de 10 sessões consecutivas. Trata-se de estudo randomizado controlado, no qual 64 participantes foram submetidos a dois procedimentos radiológicos, antes e durante a tração. As distâncias das bordas anteriores e posteriores do corpo vertebral C2 até as do corpo vertebral de C7 foram mensuradas e comparadas. Na primeira etapa as medidas das bordas anteriores foi de 8,40 para 8,50 cm (P<0,001) e nas posteriores foi de 8,35 para 8,50 cm (P<0,001). Para a segunda etapa, os indivíduos foram aleatorizados em grupo controle (n=31) e intervenção (n=33), o qual recebeu dez sessões tração cervical. Após as sessões, as distâncias anterior e posterior do grupo intervenção aumentaram significativamente de 8,40 para 8,90 cm (P<0,001) e de 8,40 para 8,65 cm (P<0,001), respectivamente. Após as trações, todos os participantes repetiram os mesmos procedimentos radiológicos, as mensurações e as comparações das distâncias vertebrais. Quando os dois grupos foram comparados após as trações, houve diferença estatisticamente significante entre as distâncias anteriores e posteriores, de 8,20 e 8,90 cm (P=0,015) e de 8,30 e 8,65cm (P=0,030), respectivamente. Portanto, a tração aumentou o comprimento da coluna cervical. Após um período de aplicação das sessões, ocorreu aumento significativo das medidas entre as vértebras.

The objectives of the study were to measure the length of the cervical spine when submitted to manual traction and to verify changes in the cervical spine after 10 consecutive sessions. In this randomized controlled study 64 participants were submitted to two radiological procedures: one before and another during traction. The distances between the anterior and posterior vertebrae edges of C2 the C7 were measured and compared. In the first stage it was shown that measures of the anterior distance was 8.40 to 8.50 cm (P<0.001) and the posterior was 8.35 to 8.50 cm (P<0.001). For the second stage, subjects were randomized in control group (n=31) and intervention group (n=33) which received ten sessions of cervical traction. After the sessions the anterior and posterior distances of the intervention group increased significantly from 8.40 to 8.90 cm (P<0.001) and 8.40 to 8.65 cm (P<0.001) respectively. After the sessions all participants repeated the same radiological procedures, measurements and comparisons of the vertebral distance. When the groups were compared after the sessions there were statistically significant differences between the anterior and posterior distance of 8.20 and 8.90 cm (P=0.015) and 8.30 and 8.65 (P=0.030) respectively. Therefore the traction increased the length of the cervical spine and after a period of application of this intervention there was significant increase of the measures between the vertebral distances.

Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

O exercício físico atenua o déficit autonômico cardíaco induzido pelo bloqueio da síntese do óxido nítrico / El ejercicio físico atenúa el déficit autonómico cardiaco inducido por el bloqueo de la síntesis de óxido nítrico / Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade

FUNDAMENTO: O bloqueio da síntese do óxido nítrico (NO) é caracterizado pelo aumento da atividade simpática cardíaca, e o treinamento físico promove a redução da atividade simpática. OBJETIVO: Investigamos o efeito do bloqueio da síntese do NO sobre o controle autonômico cardiovascular em ratos submetidos ao exercício aeróbio durante dez semanas. MÉTODOS: Ratos wistar foram divididos em quatro grupos: controle tratados com ração e água ad libitum durante dez semanas (RC); controle tratados com N G-nitro-L-arginine methyl ester (L-NAME) na última semana (RCL); treinados durante dez semanas em esteira motorizada (RT); treinados por dez semanas e tratados com L-NAME na última semana (RTL). O controle autonômico cardiovascular foi investigado em todos os grupos com a utilização de duplo bloqueio com metilatropina e propranolol, e análise da variabilidade. RESULTADOS: Os grupos RCL e RTL apresentaram hipertensão. O grupo RCL apresentou taquicardia e predomínio do tônus simpático na determinação da FC após o bloqueio autonômico farmacológico. O grupo RT apresentou bradicardia e menor freqüência cardíaca (FC) intrínseca em relação aos demais. A avaliação da variabilidade da FC mostrou menores valores absolutos e normalizados na banda de baixa freqüência (BF) no grupo RCL. Por sua vez, o grupo RTL apresentou elevação na banda de BF em valores absolutos. A análise da variabilidade da PAS mostrou que os grupos RCL e RTL apresentaram maiores valores na banda de BF. CONCLUSÃO: O exercício físico prévio impediu o déficit no controle autonômico cardíaco induzido pelo tratamento com L-NAME, no entanto não impediu o aumento na variabilidade da PAS.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

FUNDAMENTO: El bloqueo de la síntesis de óxido nítrico (NO) se caracteriza por el incremento de la actividad simpática cardiaca, y el entrenamiento físico promueve la reducción de la actividad simpática. OBJETIVO: Investigamos el efecto del bloqueo de la síntesis del NO sobre el control autonómico cardiovascular en ratones sometidos al ejercicio aerobio durante diez semanas. MÉTODOS: Se dividieron ratones wistar en cuatro grupos: control tratados con ración y agua ad libitum durante diez semanas (RC); control tratados con NG-nitro-L-arginina metil éster (L-NAME) en la última semana (RCL); entrenados durante diez semanas en cinta motorizada (RT); entrenados por diez semanas y tratados con L-NAME en la última semana (RTL). Se investigó el control autonómico cardiovascular en todos los grupos con la utilización de doble bloqueo con metilatropina y propranolol, y análisis de la variabilidad. RESULTADOS: Los grupos RCL y RTL presentaron hipertensión. El grupo RCL presentó taquicardia y predominio del tono simpático en la determinación de la FC tras el bloqueo autonómico farmacológico. El grupo RT presentó bradicardia y menor frecuencia cardiaca (FC) intrínseca en relación a los demás. La evaluación de la variabilidad de la FC mostró menores valores absolutos y normalizados en la banda de baja frecuencia (BF) en el grupo RCL. El grupo RTL presentó elevación en la banda de BF en valores absolutos. El análisis de la variabilidad de la PAS mostró que los grupos RCL y RTL presentaron mayores valores en la banda de BF. CONCLUSIÓN: El ejercicio físico previo impidió el déficit en el control autonómico cardiaco inducido por el tratamiento con L-NAME, pero no impidió el aumento en la variabilidad de la PAS.

Análise radiográfica da coluna cervical em indivíduos assintomáticos submetidos a tração manual / Radiographic analysis of the cervical spine in healthy individuals submitted to manual traction

OBJETIVO: Avaliar, radiograficamente, o efeito da tração manual sobre o comprimento da coluna cervical. MATERIAIS E MÉTODOS: Cinqüenta e cinco participantes de ambos os gêneros - 12 masculinos (22 por cento) e 43 femininos (78 por cento) - sem história de distúrbios cervicais contituíram a amostra deste estudo. Eles foram submetidos a dois procedimentos radiológicos, um antes e outro durante a tração manual sustentada por 120 segundos. As distâncias entre as bordas anteriores e posteriores da segunda à sétima vértebras cervicais foram mensuradas e comparadas antes e durante a tração manual. RESULTADOS: A mediana da distância anterior antes da tração foi de 8,40 cm e durante a tração aumentou para 8,50 cm (p=0,002). A mediana da distância posterior antes da tração foi de 8,35 cm e durante a tração aumentou para 8,50 cm (p<0,001). CONCLUSÃO: Os resultados demonstraram que a aplicação da tração manual promoveu aumento estatisticamente significante do comprimento da coluna cervical em indivíduos assintomáticos.

OBJECTIVE: To evaluate radiographically the effect of manual traction on the length of the cervical spine in healthy individuals. MATERIALS AND METHODS: The sample of the present study included 55 individuals - 12 men (22 percent) and 43 women (78 percent) - with no previous history of cervical disorders, submitted to two radiological procedures previously and during manual traction sustained for 120 seconds. Distances between the anterior and posterior edges from the second to the seventh cervical vertebrae were measured and compared before and during manual traction. RESULTS: The median of pre-traction anterior length was 8.40 cm, increasing to 8.50 cm during the traction (p=0.002); and the median of pre-traction posterior length was 8.35 cm, increasing to 8.50 cm during traction (p<0.001). CONCLUSION: Application of manual traction resulted in a statistically significant increase in the length the cervical spine in healthy individuals.

The effect of ovariectomy on cardiac autonomic control in rats submitted to aerobic physical training.

We have investigated the ovariectomy effects on the cardiovascular autonomic adaptations induced by aerobic physical training and the role played by nitric oxide (NO). Female Wistar rats (n=70) were divided into five groups: Sedentary Sham (SS); Trained Sham (TS); Trained Hypertensive Sham treated with N(G)-nitro-L-arginine methyl ester (L-NAME) (THS); Trained Ovariectomized (TO); and Trained Hypertensive Ovariectomized treated with L-NAME (THO). Trained groups were submitted to a physical training during 10 weeks. The cardiovascular autonomic control was investigated in all groups using different approaches: 1) pharmacological evaluation of autonomic tonus with methylatropine and propranolol; 2) analysis of heart rate (HR) and systolic arterial pressure (AP) variability; 3) spontaneous baroreflex sensitivity (BRS) evaluation. Hypertension was observed in THS and THO groups. Pharmacological analysis showed that TS group had increased predominance of autonomic vagal tonus compared to SS group. HR and intrinsic HR were found to be reduced in all trained animals. TS group, compared to other groups, showed a reduction in LF oscillations (LF=0.2-0.75 Hz) of pulse interval in both absolute and normalized units as well as an increase in HF oscillations (HF=0.75-2.50 Hz) in normalized unit. BRS analysis showed that alpha-index was different between all groups. TS group presented the greatest value, followed by the TO, SS, THO and THS groups. Ovariectomy has negative effects on cardiac autonomic modulation in trained rats, which is characterized by an increase in the sympathetic autonomic modulation. These negative effects suggest NO deficiency. In contrast, the ovariectomy seems to have no effect on AP variability.

Heart rate and arterial pressure variability in the experimental renovascular hypertension model in rats.

This study was conducted in one kidney, one clip (1K1C) Goldblatt hypertensive rats to evaluate vascular and cardiac autonomic control using different approaches: 1) evaluation of the autonomic modulation of heart rate (HR) and systolic arterial pressure (SAP) by means of autoregressive power spectral analysis 2) assessment of the cardiac baroreflex sensitivity; and 3) double blockade with methylatropine and propranolol. The 1K1C group developed hypertension and tachycardia. The 1K1C group also presented reduction in variance as well as in LF (0.23+/-0.1 vs. 1.32+/-0.2 ms2) and HF (6.6+/-0.49 vs. 15.1+/-0.61 ms2) oscillations of pulse interval. Autoregressive spectral analysis of SAP showed that 1K1C rats had an increase in variance and LF band (13.3+/-2.7 vs. 7.4+/-1.01 mmHg2) in comparison with the sham group. The baroreflex gain was attenuated in the hypertensive 1K1C (-1.83+/-0.05 bpm/mmHg) rats in comparison with normotensive sham (-3.23+/-0.06 bpm/mmHg) rats. The autonomic blockade caused an increase in the intrinsic HR and sympathetic predominance on the basal HR of 1K1C rats. Overall, these data indicate that the tachycardia observed in the 1K1C group may be attributed to intrinsic cardiac mechanisms (increased intrinsic heart rate) and to a shift in the sympathovagal balance towards cardiac sympathetic over-activity and vagal suppression associated to depressed baroreflex sensitivity. Finally, the increase in the LF components of SAP also suggests an increase in sympathetic activity to peripheral vessels.

Nitric oxide synthesis blockade increases hypertrophy and cardiac fibrosis in rats submitted to aerobic training.

OBJECTIVE: The objective of the present study was to evaluate cardiac tissue adaptations in rats submitted to aerobic training after nitric oxide (NO) synthesis blockade. METHODS: The animals (n=48) were divided into four groups: sedentary (CONTROL group); hypertensive after administration of NG-nitro-L-arginine methyl ester for 7 days (L-NAME Group); trained for 8 weeks through swimming exercises (TRAINED Group);trained and treated with L-NAME during the last week (L-NAME TRAINED Group). All the animals were submitted to the experiment procedures for blood pressure (BP) readings and cardiac morphometric evaluation. RESULTS: In comparison to the other groups, the L-NAME and L-NAME TRAINED groups were hypertensive (p<0.05); however, BP elevation in the L-NAME TRAINED group was significantly lower than the L-NAME group (p<0.05). The heart weight indexes for the TRAINED and L-NAME TRAINED groups were higher than the CONTROL and L-NAME groups (p<0.05). Also they had presented higher rates of macroscopic cardiac area and cardiac fibrosis in relation to the rest (p<0.05); comparisons revealed that the values for the L-NAME TRAINED group were significantly higher (p<0.05) than the others. CONCLUSION: Short term NO synthesis blockade in sedentary animals induced hypertension but did not cause cardiac hypertrophy. In the trained animals, the inhibition of NO synthesis attenuated hypertension, induced cardiac hypertrophy and significantly increased myocardial fibrosis, indicating that NO plays an important role in cardiac tissue adaptations caused by aerobic exercise.

O bloqueio da síntese do óxido nítrico promove aumento da hipertrofia e da fibrose cardíaca em ratos submetidos a treinamento aeróbio / Nitric oxide synthesis blockade increases hypertrophy and cardiac fibrosis in rats submitted to aerobic training

OBJETIVO: O presente estudo avaliou as adaptações teciduais cardíacas em ratos submetidos a treinamento aeróbio, após o bloqueio da síntese de óxido nítrico (NO). MÉTODOS: Os animais (n = 48) foram divididos em quatro grupos: sedentários (grupo CONTROLE), hipertensos após administração de Ng-nitro-L-arginina metil éster durante sete dias (grupo L-NAME), treinados por meio de natação durante oito semanas (grupo TREINADO) e treinados e tratados com L-NAME na última semana (grupo TREINADO L-NAME). Em todos os animais foi registrada a pressão arterial (PA) e realizada a avaliação morfométrica cardíaca. RESULTADOS: Os grupos L-NAME e TREINADO L-NAME apresentaram-se hipertensos em relação aos demais (p < 0,05), porém a elevação da PA no grupo TREINADO L-NAME foi significativamente menor em relação ao L-NAME (p < 0,05). Os grupos TREINADO e TREINADO L-NAME apresentaram índice de peso cardíaco maior que os grupos CONTROLE e L-NAME (p < 0,05). Também apresentaram maiores índices de área cardíaca macroscópica e de fibrose cardíaca em relação aos demais (p < 0,05) e, quando comparados, o grupo TREINADO L-NAME mostrou-se significativamente superior (p < 0,05). CONCLUSÃO: O bloqueio a curto prazo da síntese de NO, em animais sedentários, induziu hipertensão, sem no entanto causar hipertrofia cardíaca. Nos animais treinados, a inibição da síntese de NO atenuou a hipertensão e promoveu hipertrofia cardíaca com aumento expressivo da fibrose miocárdica, sugerindo importante papel do NO nas adaptações teciduais cardíacas induzidas pelo treinamento físico aeróbio.

OBJECTIVE: The objective of the present study was to evaluate cardiac tissue adaptations in rats submitted to aerobic training after nitric oxide (NO) synthesis blockade. METHODS: The animals (n=48) were divided into four groups: sedentary (CONTROL group); hypertensive after administration of NG-nitro-L-arginine methyl ester for 7 days (L-NAME Group); trained for 8 weeks through swimming exercises (TRAINED Group);trained and treated with L-NAME during the last week (L-NAME TRAINED Group). All the animals were submitted to the experiment procedures for blood pressure (BP) readings and cardiac morphometric evaluation. RESULTS: In comparison to the other groups, the L-NAME and L-NAME TRAINED groups were hypertensive (p<0.05); however, BP elevation in the L-NAME TRAINED group was significantly lower than the L-NAME group (p<0.05). The heart weight indexes for the TRAINED and L-NAME TRAINED groups were higher than the CONTROL and L-NAME groups (p<0.05). Also they had presented higher rates of macroscopic cardiac area and cardiac fibrosis in relation to the rest (p<0.05); comparisons revealed that the values for the L-NAME TRAINED group were significantly higher (p<0.05) than the others. CONCLUSION: Short term NO synthesis blockade in sedentary animals induced hypertension but did not cause cardiac hypertrophy. In the trained animals, the inhibition of NO synthesis attenuated hypertension, induced cardiac hypertrophy and significantly increased myocardial fibrosis, indicating that NO plays an important role in cardiac tissue adaptations caused by aerobic exercise.