Predicting urine output after kidney transplantation: development and internal validation of a nomogram for clinical use

ABSTRACT Purpose: To analyze pre-transplantation and early postoperative factors affecting post-transplantation urine output and develop a predictive nomogram. Patients and Methods: Retrospective analysis of non-preemptive first transplanted adult patients between 2001-2016. The outcomes were hourly diuresis in mL/Kg in the 1st (UO1) and 8th (UO8) postoperative days (POD). Predictors for both UO1 and UO8 were cold ischemia time (CIT), patient and donor age and sex, HLA I and II compatibility, pre-transplantation duration of renal replacement therapy (RRT), cause of ESRD (ESRD) and immunosuppressive regimen. UO8 predictors also included UO1, 1st/0th POD plasma creatinine concentration ratio (Cr1/0), and occurrence of acute cellular rejection (AR). Multivariable linear regression was employed to produce nomograms for UO1 and UO8. Results: Four hundred and seventy-three patients were included, mostly deceased donor kidneys' recipients (361, 70.4%). CIT inversely correlated with UO1 and UO8 (Spearman's p=-0.43 and −0.37). CR1/0 inversely correlated with UO8 (p=-0.47). On multivariable analysis UO1 was mainly influenced by CIT, with additional influences of donor age and sex, HLA II matching and ESRD. UO1 was the strongest predictor of UO8, with significant influences of AR and ESRD. Conclusions: The predominant influence of CIT on UO1 rapidly wanes and is replaced by indicators of functional recovery (mainly UO1) and allograft's immunologic acceptance (AR absence). Mean absolute errors for nomograms were 0.08 mL/Kg h (UO1) and 0.05 mL/Kg h (UO8).

Fluid balance in pediatric patients in prone position: a pragmatic study

SUMMARY OBJECTIVE: To verify the association between prone position, increased diuresis, and decreased cumulative fluid balance in critically ill pediatric patients who underwent mechanical ventilation (MV) for pulmonary causes and describe adverse events related to the use of the position. METHODS: This is a retrospective observational study. Patients aged between 1 month and 12 years who underwent MV for pulmonary causes, between January 2013 and December 2015, were selected and divided between those who were put on prone position (PG) and those who were not (CG) during the hospitalization at the Pediatric Intensive Care Unit (PICU). Data were analyzed longitudinally from D1 to D4. RESULTS: A total of 77 patients (PG = 37 and CG = 40) were analyzed. The general characteristics of both groups were similar. In the comparison between the groups, there was no increase in diuresis or decrease in cumulative fluid balance in the prone group. In the longitudinal analysis of D1 to D4, we saw that the PG presented higher diuresis (p = 0.034) and a lower cumulative fluid balance (p = 0.001) in D2. Regarding the use of diuretics, there was greater use of furosemide (P <0.001) and spironolactone (P = 0.04) in the PG. There was no increase in adverse events during the use of the prone position. CONCLUSION: The prone position was not associated with increased diuresis or decreased cumulative fluid balance in critically ill pediatric patients who underwent to MV for pulmonary causes.

RESUMO OBJETIVO: Verificar a associação entre posição prona, aumento da diurese e diminuição do balanço hídrico em pacientes pediátricos criticamente enfermos e submetidos à ventilação mecânica (VM) por causa pulmonar, além de descrever eventuais intercorrências relacionadas à aplicação dessa posição. MÉTODOS: Estudo observacional retrospectivo. Pacientes submetidos à VM por causa pulmonar, com idade entre 1 mês e 12 anos no período entre janeiro de 2013 e dezembro de 2015, foram selecionados e divididos entre os que receberam posição prona (GP) e os que não receberam (GC) durante a internação na Unidade de Terapia Intensiva Pediátrica (Utip). Os dados foram analisados longitudinalmente de D1 a D4. RESULTADOS: Foram analisados77 pacientes (GP=37 e GC=40). Em termos de características gerais, os grupos foram semelhantes entre si. Na comparação entre os grupos, não houve aumento da diurese ou diminuição do balanço hídrico cumulativo no grupo prona. Na análise longitudinal de D1 a D4, evidenciou-se que o GP apresentou maior diurese (p=0,034) e menor balanço hídrico cumulativo (p = 0,001) no D2. Com relação ao uso de diuréticos, houve maior uso de furosemida (P<0,001) e de espironolactona (P=0,04) no GP. Não houve aumento de eventos adversos durante a utilização da posição prona. CONCLUSÃO: A posição prona não demonstrou associação com aumento da diurese ou diminuição de balanço hídrico cumulativo em pacientes críticos pediátricos submetidos à VM por causa pulmonar.

Morfologia e função cardíacas em pacientes renais crônicos, com ou sem diurese residual, em tratamento hemodialítico / Cardiac morphology and function in patients with and without residual diuresis on hemodialysis

Em pacientes com doença renal crônica (DRC) em hemodiálise (HD), a hipertrofia ventricular esquerda (HVE) está relacionada ao aumento do índice de resistência vascular periférica (IRVP) total e à sobrecarga de volume. A presença da diurese residual (DR) nesses pacientes possibilita maior controle volêmico. Avaliamos as modificações morfofuncionais do ventrículo esquerdo (VE) em pacientes com DRC em HD com e sem diurese residual. Trinta e um pacientes não diabéticos foram divididos em dois grupos: com diurese residual (DR+) (n = 17) e sem diurese residual (DR-) (n = 14). Em ambos os grupos, DR+ vs. DR-, ocorreram diferenças no índice cardíaco (3,9 ± 0,20 vs. 3,0 ± 0,21 L/min/m²; p = 0,0056), no índice sistólico (54 ± 2,9 vs. 45 ± 3,3 mL/b/m²; p = 0,04), no volume diastólico final (141 ± 6,7 vs. 112 ± 7,6 mL; p = 0,008), no diâmetro diastólico final (52 ± 0,79 vs. 48 ± 1,12 mm; p = 0,0072) e no IRVP total (1.121 ± 56 vs. 1.529 ± 111 dina.seg.cm-5; p = 0,001). O grupo DR+ apresentou menor espessamento relativo de parede (ERP) do que o DR- (0,38 ± 0,01 vs. 0,45 ± 0,01; p = 0,0008). A fração de ejeção (66,00 ± 1,24 vs. 66,0 ± 1,46 por cento; p = 0,873) e o índice de massa ventricular esquerda (132 ± 6,0 vs. 130 ± 8,3 g/m; p = 0,798) foram similares em ambos os grupos. O volume de diurese residual correlacionou-se com o espessamento da parede ventricular (r = 0,42; p = 0,0186) e com o índice de resistência vascular periférica (r = -0,48; p = 0,0059). Em conclusão, a presença ou não da diurese residual, em pacientes com doença renal crônica e em hemodiálise, pode ser responsável por modificações na função cardíaca sistólica.

In patients with chronic renal failure on hemodialysis, left ventricular hypertrophy is related to the increase in total peripheral vascular resistance and volume overload. The presence of residual diuresis enables greater control of the volemia of these. We evaluated the morpho-functional changes of the left ventricle in patients with chronic kidney disease on hemodyalisis treatment with and without residual diuresis. A total of 31 non diabetic patients were studied and they were divided into two groups: with residual diuresis (RD+) (n = 17) and without residual diuresis (RD-) (n = 14). In both groups, RD+ vs. RD-, using data from a Doppler echocardiogram differences were found, respectively, in the cardiac index (3.9 ± 0.2 vs. 3.0 ± 0.2 L/min/m²; p = 0.0056), systolic index (54 ± 2.9 vs. 45 ± 3.3 mL/b/m²; p = 0.04), end diastolic volume (141 ± 6.7 vs. 112 ± 7.6 mL; p = 0.008), end diastolic diameter (52 ± 0.7 vs. 48 ± 1.1 mm; p = 0.0072) and total peripheral resistance index (1121 ± 56 vs. 1529 ± 111 dyne.sec.cm-5; p = 0.001). RD+ had lower relative wall thickness than RD- (0.38 ± 0.01 vs. 0.45 ± 0.01; p = 0.0008). The ejection fraction and the left ventricular mass index were similar in both groups. The urinary 24-hour volume correlated with the relative wall thickness (r = -0.42; p = 0.0186) and with peripheral resistance index (r = -0.48; p = 0.0059). In conclusion, there were distinct ventricular geometric patterns and different functional performances between RD+ and RD- groups. The presence of residual diuresis can be responsible by these modifications in systolic function.

Patterns of renal dopamine release to regulate diuresis and natriuresis during volume expansion: Role of renal monoamine-oxidase / Perfiles de secreción de dopamina renal en la expansión de volumen para regular diuresis y natriuresis: Rol de la monoaminoxidasa renal

Diuretic and natriuretic effects of renal dopamine (DA) are well established. However, in volume expansion the pattern of renal DA release into urine (U DA V) and the role of enzymes involved in DA synthesis/degradation have not yet been defined. The objective was to determine the pattern of U DA V during volume expansion and to characterize the involvement of monoamine-oxidase (MAO) and aromatic amino-acid decarboxylase (AADC) in this response. In this study male Wistar rats were expanded with NaCl 0.9% at a rate of 5% BWt per hour. At the beginning of expansion three groups received a single drug injection as follows: C (vehicle, Control), IMAO (MAO inhibitor Pargyline, 20 mg/kg BWt, i.v.) and BNZ (AADC inhibitor Benserazide, 25 mg/kg BWt, i.v.). Results revealed that in C rats U DA V (ng/30 min/100g BWt) increased in the first 30 min expansion from 11.5 ± 1.20 to 21.8 ± 3.10 (p < 0.05) and decreased thereafter. IMAO showed a similar pattern but significantly higher than C at 30 min expansion (32.5 ± 2.20, p < 0.05). IMAO greatly reduced MAO activity from 8.29 ± 0.35 to 1.1 ± 0.03 nmol/mg tissue/hour and significantly increased diuresis and natriuresis over controls. BNZ abolished the early U DA V peak to 3.2±0.72 (p < 0.01) and though, U DA V increased over C after 60 min expansion, natriuresis and diuresis were diminished by BNZ treatment. Results indicate that an increment in renal DA release into urine occurs early in expansion and in a peak-shaped way. In this response MAO plays a predominant role.

La dopamina (DA) intrarrenal ejerce efectos diuréticos y natriuréticos. Sin embargo, en los estado de expansión de volumen aún no está bien definido el patrón de liberación de dopamina renal hacia la orina y si cumplen un rol las enzimas involucradas en la síntesis o degradación de la amina. El objetivo del presente trabajo fue determinar el patrón de excreción urinaria de DA (U DA V) durante la expansión de volumen, caracterizando la participación de las enzimas monoaminooxidasa (MAO) y decarboxilasa de aminoácidos aromáticos (AADC) en esta respuesta. Para ello ratas Wistar macho fueron expandidas de volumen con NaCl 0.9% al 5% del peso corporal por hora durante dos horas y divididas en tres grupos, los que al comienzo de la expansión recibieron: C (vehículo, Control), IMAO (Pargilina, inhibidor de MAO, 20 mg/kg PC, i.v.) y BNZ (Benserazida, inhibidor de AADC, 25 mg/kg PC, i.v.). Se observó que en C la U DA V (ng/30min/100gPC) aumentó durante los primeros 30 minutos de expansión de 11.5 ± 1.20 a 21.8 ± 3.10 (p < 0.05), disminuyendo posteriormente. IMAO mostró un patrón de liberación similar pero significativamente mayor que C a los 30 min de expansión (32.5 ± 2.20, p < 0.05). En este grupo la actividad de MAO disminuyó de 8.29 ± 0.35 a 1.1 ± 0.03 nmol/mg tejido/hora y aumentaron la diuresis y natriuresis por sobre los controles. En BNZ, el pico de U DA V observado a los 30 min de la expansión disminuyó a 3.2 ± 0.72 (p < 0.01), aunque luego de 60 minutos fue mayor que en C. BNZ disminuyó tanto la diuresis como la natriuresis. Podemos concluir que al comienzo de la expansión de volumen se produce un pico de excreción de dopamina renal hacia la orina. La enzima MAO juega un rol fundamental en esta respuesta.

Influence of renal denervation on blood pressure, sodium and water excretion in acute total obstructive apnea in rats

Obstructive apnea (OA) can exert significant effects on renal sympathetic nerve activity (RSNA) and hemodynamic parameters. The present study focuses on the modulatory actions of RSNA on OA-induced sodium and water retention. The experiments were performed in renal-denervated rats (D; N = 9), which were compared to sham (S; N = 9) rats. Mean arterial pressure (MAP) and heart rate (HR) were assessed via an intrafemoral catheter. A catheter was inserted into the bladder for urinary measurements. OA episodes were induced via occlusion of the catheter inserted into the trachea. After an equilibration period, OA was induced for 20 s every 2 min and the changes in urine, MAP, HR and RSNA were recorded. Renal denervation did not alter resting MAP (S: 113 ± 4 vs D: 115 ± 4 mmHg) or HR (S: 340 ± 12 vs D: 368 ± 11 bpm). An OA episode resulted in decreased HR and MAP in both groups, but D rats showed exacerbated hypotension and attenuated bradycardia (S: -12 ± 1 mmHg and -16 ± 2 bpm vs D: -16 ± 1 mmHg and 9 ± 2 bpm; P < 0.01). The basal urinary parameters did not change during or after OA in S rats. However, D rats showed significant increases both during and after OA. Renal sympathetic nerve activity in S rats increased (34 ± 9 percent) during apnea episodes. These results indicate that renal denervation induces elevations of sodium content and urine volume and alters bradycardia and hypotension patterns during total OA in unconscious rats.

GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats

We investigated the involvement of GABAergic mechanisms of the central amygdaloid nucleus (CeA) in unanesthetized rats subjected to acute isotonic or hypertonic blood volume expansion (BVE). Male Wistar rats bearing cannulas unilaterally implanted in the CeA were treated with vehicle, muscimol (0.2 nmol/0.2 µL) or bicuculline (1.6 nmol/0.2 µL) in the CeA, followed by isotonic or hypertonic BVE (0.15 or 0.3 M NaCl, 2 mL/100 g body weight over 1 min). The vehicle-treated group showed an increase in sodium excretion, urinary volume, plasma oxytocin (OT), and atrial natriuretic peptide (ANP) levels compared to control rats. Muscimol reduced the effects of BVE on sodium excretion (isotonic: 2.4 ± 0.3 vs vehicle: 4.8 ± 0.2 and hypertonic: 4.0 ± 0.7 vs vehicle: 8.7 ± 0.6 µEq·100 g-1·40 min-1); urinary volume after hypertonic BVE (83.8 ± 10 vs vehicle: 255.6 ± 16.5 µL·100 g-1·40 min-1); plasma OT levels (isotonic: 15.3 ± 0.6 vs vehicle: 19.3 ± 1 and hypertonic: 26.5 ± 2.6 vs vehicle: 48 ± 3 pg/mL), and ANP levels (isotonic: 97 ± 12.8 vs vehicle: 258.3 ± 28.1 and hypertonic: 160 ± 14.6 vs vehicle: 318 ± 16.3 pg/mL). Bicuculline reduced the effects of isotonic or hypertonic BVE on urinary volume and ANP levels compared to vehicle-treated rats. However, bicuculline enhanced the effects of hypertonic BVE on plasma OT levels. These data suggest that CeA GABAergic mechanisms are involved in the control of ANP and OT secretion, as well as in sodium and water excretion in response to isotonic or hypertonic blood volume expansion.

Pressão arterial sistêmica e diurese residual em pacientes com doença renal crônica em hemodiálise / Systemic blood pressure and residual urine output in chronic hemodialysis patients

Introdução: A função renal residual (FRR) em portadores de insuficiência renal crônica (IRC) submetidos à diálise é reconhecida como fator relevante naredução do risco relativo de morte neste grupo de pacientes. Pacientes com maiores níveis de FRR e de volume de diurese residual (VDR) tem maiorliberdade na ingestão de líquidos e melhor controle do balanço hídrico. Objetivo: Analisar transversalmente o VDR de pacientes com IRC submetidos àhemodiálise (HD) e sua relação com os níveis pressóricos sistêmicos. Pacientes e Métodos: Foram estudados 144 pacientes, divididos em dois grupos:os anúricos (A; n=80) e os não anúricos (NA; n=64). A pressão arterial sistêmica, aferida antes e após as últimas 3 sessões de hemodiálise, o ganho de peso interdialítico e o volume de ultrafiltrado eram anotados. Os pacientes foram submetidos a um questionário onde eram perguntados sobre o volume de urina eliminado no dia anterior à hemodiálise. Resultados: A pressão arterial sistólica após a sessão de hemodiálise foi maior no grupo A (130 ± 2,3versus 119 ± 4,0 mmHg, p <0,05). Em contraste, a pressão arterial diastólica do grupo A só foi maior do que aquela observada no grupo NA antes dasessão de hemodiálise (82 ± 1.6 mm/Hg versus 77 ± 1,8 mm/Hg; p<0,05). O grupo A obteve maior ganho de peso no período entre as sessões de HD (3,2 ± 1.5 versus 2.0 ± 1,8 Kg, p <0,05). O número de anti-hipertensivos usados pelo grupo A foi de 1,92 ± 0,16 unidades e pelo grupo NA foi de 1,76 ±0,17 unidades (NS, p >0,05). Conclusão: A ausência da diurese residual nos pacientes em hemodiálise associa-se a maiores valores da pressão arterial sistêmica, principalmente os níveis diastólicos. A hemodiálise reduz os valores da PAD nos indivíduos anúricos igualando-os aos dos indivíduos não anúricos. Esforços devem ser empregados para prevenção da diurese residual, visando melhor controle hídrico e pressórico dos pacientes em hemodiálise.

Introduction: The residual renal function (RRF) in patients with chronic renal failure is recognized as a relevant factor to reduce the relative risk of deathin these patients. Higher levels of RRF and residual urine output allow more flexible water intake and a better control of the volume status. Objectives: The aim of this study was to evaluate the urine output of patients with chronic renal failure under hemodialysis treatment and to analyze its relationship to the systemic blood pressures levels of patients with or without residual urine volume. Patients and Methods: One-hundred and forty-four patients comprising an anuric group (A; n= 80) and a non-anuric one (NA; n= 64). The systemic arterial blood pressure, which was verified pre- and post- the last 3 hemodialysis sessions, weight gain between sessions, and the ultrafiltration volume along the dialysis sessions were registered. The patients answered a questionnaire about the urine output the day before the hemodialysis session. Results: The systolic blood pressure level was higher in group A after hemodialysis (130 ± 2.3 versus 119 ± 4.0 mmHg, p < 0.05). In contrast, the diastolic blood pressure in group A was higher than that observed in those of group NA only beforethe dialysis session (82 ± 1.6 versus 77 ± 1.8 mmHg; p < 0.05). Group A had a larger weight gain between hemodialysis sessions (3.2 ± 1.5 versus 2.0 ± 1.8 kg, p < 0.05). The number of blood pressure drugs administered to the patients in group A was 1.92 ± 0.16 units; and to those in group NA was 1.76 ± 0.17 units (NS). Conclusion: The absence of residual urine volume in hemodialysis patients was associated with higher levels of predialysis diastolic blood pressure . Hemodialysis reduced the diastolic blood pressure values in anuric patients in a way that their values became similar to those found in non-anuric ones...

Rhodnius prolixus Malpighian tubules and control of diuresis by neurohormones

Rhodnius prolixus Malpighian tubules (MTs) are a good model for fluid and ion secretion studies in view of the dramatic postprandial diuresis, which follows its massive blood meals. Ingestion of a blood meal equals to 10-12 times their initial body mass, leads to rapid activation of high output by excretory system, which eliminates 40-50 percent of the fluid mass. Secretion of ions and water is stimulated 1000-fold by serotonin and diuretic hormone. These hormones cooperate synergistically to activate adenylate cyclase activity from MTs cells, which increase the level of intracellular cAMP. The anti-diuretic hormones have also an important role in the fluid maintenance of Rhodnius prolixus. Several hours after insect feeding occurs a reduction in urine flow, that has been thought to result from a decreased diuretic hormone release or from a novel mechanism of anti-diuresis involving insect cardioacceleratory peptide 2b (CAP2b) and cyclic GMP. In this article it is discussed how the hormone regulation of fluid transport is done in Rhodnius prolixus MTs.

Os túbulos de Malpighi (TMs) de Rhodnius prolixus são reconhecidos por serem excelentes modelos para o estudo da secreção de fluidos e íons devido a grande diurese que ocorre quando esses animais se alimentam de sangue. O inseto, após alimentação, pode aumentar seu peso corporal inicial em até 10-12 vezes, o que leva a rápida ativação do sistema excretor, que elimina 40-50 por cento do fluido corporal. A secreção de íons e água é estimulada 1000 vezes pela serotonina e pelos hormônios diuréticos. Esses hormônios agem sinergicamente ativando a adenil ciclase das células dos TMs, aumentando os níveis intracelulares de AMPc. Os hormônios anti-diuréticos também têm um importante papel na manutenção dos fluídos corporais do Rhodnius prolixus. Várias horas após a alimentação do inseto ocorre uma redução do fluxo urinário, o que foi sugerido ser decorrente da diminuição da liberação dos hormônios diuréticos ou da anti-diurese envolvendo o peptídeo cardioaceleratório 2b (CAP2b) e o GMPc. Neste artigo é discutida a regulação hormonal do transporte de fluido nos MTs de Rhodnius prolixus.

Terapia da insuficiência cardíaca avançada ajustada por objetivos hemodinâmicos obtidos pela monitorização invasiva / Advanced heart failure therapy adapted to hemodynamic objectives acquired from invasive hemodynamic monitoring

OBJETIVO: Avaliar o tratamento da insuficiência cardíaca (IC) avançada em relação à redução das pressões de enchimento ventricular, com a utilização de doses maiores de vasodilatadores, através da monitorização hemodinâmica invasiva. MÉTODOS: Foram estudados 19 pacientes com IC avançada, nos quais foi instalado o cateter de Swan-Ganz para guiar a administração de diurético intravenoso (IV) e nitroprussiato de sódio, com o objetivo de se reduzir de forma significativa as pressões de enchimento ventricular. Depois de alcançado esse objetivo ou 48 horas, foram introduzidas drogas orais até serem retirados os fármacos venosos, mantendo o benefício hemodinâmico. RESULTADOS: Dos 19 pacientes estudados, 16 (84 por cento) eram do sexo masculino. A idade média foi de 66 ± 11,4 anos; a fração de ejeção média foi de 26 ± 6,3 por cento; 2 pacientes (10,5 por cento) apresentavam classe funcional (CF) III e 17 (89,5 por cento), CF IV. Houve queda da pressão de oclusão da artéria pulmonar de 23 ± 11,50 mmHg para 16 ± 4,05 mmHg (p=0,008), do índice de resistência vascular sistêmica de 3.023 ± 1.153,71 dynes/s/cm-5/m² para 1.834 ± 719,34 dynes/s/cm-5/m² (p=0,0001) e aumento do índice cardíaco de 2,1 ± 0,56 l/min/m² para 2,8 ± 0,73 l/min/m² (p=0,0003). Um subgrupo com hipovolemia foi identificado. CONCLUSÃO: Foi possível reduzir as pressões de enchimento ventricular para valores significativamente menores, obtendo melhora significativa do índice cardíaco, do índice de resistência vascular sistêmica e da pressão média da artéria pulmonar, utilizando-se doses significativamente maiores de vasodilatadores.

Relação das pressões atriais com o peptídio natriurético atrial e seus efeitos na diurese e natriurese durante operação cardíaca com circulação extracorpórea / Variations of the atrial natriuretic peptide (ANP) introduced by estracorporeal circulation (ECC) during cardiac surgery

OBJETIVO: Estudar as variações do peptídio natriurético atrial (PNA) introduzidas pela circulação extracorpórea (CEC) durante operação cardíaca e testar a hipótese de que existe correlação entre os níveis plasmáticos de PNA, pressão atrial direita (PAD) pressão atrial esquerda (PAE), diurese e natriurese. MÉTODO: Estudo de coorte de 15 pacientes submetidos a revascularização do miocárdio com CEC. Os intervalos de tempo de observação foram: t0 = 10 minutos antes da CEC (valor controle); t1 = 10 minutos depois de fluxo total em CEC; t2 30 minutos em fluxo total em CEC; t3 = fase final da CEC em temperatura nasofaringeana de 36º C; e t4 = 30 minutos após o término da CEC. RESULTADOS: Os valores do PNA, PAE e PAD variaram significativamente (p<0,001). O PNA diminuiu de t0 para t1 (NS) e após elevou-se progressivamente até t4 (p<0,001). A PAE e a PAD reduziram (p<0,001) entre t0 e t1, elevando-se progressivamente até t4 (p<0,001). O Na+ urinário aumentou entre t0 e t3 (p<0,001), com queda em t4. A diurese aumentou progressivamente em todos os tempos considerados (p<0,001). Foi encontrada correlação significativa entre PNA e o volume de diurese no t0, coeficiente de correlação de 0,535 (p=0,040), e no tempo igual a t2 entre PNA e PAD, coeficiente de correlação de 0,590 (p=0,021). CONCLUSÃO: As concentrações do PNA apresentam variações durante a operação de revascularização com CEC, o que favorece o conceito de estar relacionadas com as pressões atriais, e ao término da CEC, têm uma importante função na excreção de sódio e no volume da diurese

Does plasma ANP participate in natriuresis induced by alpha-MSH?

Alpha-Melanocyte-stimulating hormone (alpha-MSH;0.6 and 3 nmol) microinjected into the anteroventral region of the third ventricle (AV3V) induced a significant increase in diuresis without modifying natriuresis or kaliuresis. Intraperitoneal (ip) injection of alpha-MSH (3 and 9.6 nmol) induced a significant increase urinary sodium, potassium and water excretion. Intraperitoneal (3 and 4.8 nmol) or iv (3 and 9.6 nmol) administration of alpha-MSH did not induce any significant changes in plasma atrial natriuretic peptide (ANP), suggesting that the natriuresis, kaliuresis and diuresis induced by the systemic action of alpha-MSH can be dissociated from the increase in plasma ANP. These preliminary results suggest that alpha-MSH may be involved in a gamma-MSH-independent mechanism of regulation of hydromineral metabolism.

Funciones tubulares en diuresis y antidiuresis en pacientes críticos estables hemodinámicamente / Tubular functions in polyuria and oliguaria in stable critically ill patients

Introducción: los pacientes críticos tienen a menudo cambios en la función renal. Objetivo: estudiar la función tubular en pacientes estables de la UCI durante oliguria y poliuria. Pacientes y métodos: estudiaremos retrospectivamente los expedientes de 64 pacientes sin disfución renal (PFR) en orina de 24 horas: urea y creatinina séricas, osmolaridad urinaria, depuraciones de creatinina, osmolar y agua libre (Dcr, DOsm, DH2O) y las fracciones de excreción osmolar, de Na y K (FeOsm, FeNa, FeK). Resultados: se efectuaron 157 determinaciones de PFR. La DH2O, FeNa y FeNa y FeOsm fueron altas en pacientes poliúricos en comparación con los pacientes oligúricos, la osmolaridad fue baja (p<0.001) y el valor de la urea y creatinina séricas y la FeK permanecieron sin cambios; hubo una diferencia significativa en las funciones tubulares (excepto la FeK) entre la diuresis normal y la diuresis y antidiuresis (p<0.02), pero todos los valores estuvieron dentro de los límites normales. Conclusión: en los pacientes estables críticos los cambios de las funciones tubulares se encuentran dentro de los rangos fisiológicos

ANP as a neuroendocrine modulator of body fluid homeostasis

The role played by the central nervous system (CNS) in the control of body fluid homeostasis has been demonstrated by several authors. The AV3V plays a key role in central control of sodium excretion since its cholinergic, adrenergic, angiotensinergic and osmotic stimulation enhances and its destruction blocks sodium excretion in rats and goats. Cholinergic stimulation of the AV3V induced an increase in plasma ANP as well as a marked elevation in content of the peptide in medial basal hypothalamus, neuro and adenohypophysis. On the other hand, a decline in plasma ANP after AV3V lesions was accompanied by dramatic declines in content of ANP in these same structures. Our previous work has also indicated the essential role of the AV3V region and its ANPergic neurons in the control of ANP release in response to volume expansion (BVE) and indicated that alpha-adrenergic and muscarinic receptors are critical in mediating these responses. Lesions of the AV3V region, or of the median eminence or posterior lobe of pituitary gland blocked the increase in plasma ANP concentration in response to BVE. That this effect is related to blockage of the activity of the brain ANPergic neurons is supported by fyndings in sheep and in rats that the injection of the antiserum directed against ANP into the AV3V region at least partially blocked the BVE-induced release of ANP. We and others have also previously shown that denervation of baroreceptors inhibits ANP release induced by BVE. Activation of the ANP neurons also cause release of ANP from the anterior and neural lobe of pituitary gland. ANP neurons may activate oxytocinergic neurons in the supraoptic and paraventricular, which projects to neural lobe. Oxytocin would circulate to the atria and may directly activate release of ANP from the atrial myocytes, since i.v. or i.p. injection of oxytocin increases sodium excretion as well as elevates plasma ANP. Oxytoxin is present in the neural lobe in large quantity, which could reach the atria myocytes in high concentration and release ANP that circulate to the kidneys and evokes natriuresis to return circulating blood volume to normal.

Diuresis transanestésica / Trans-anesthetic diuresis

A 25 pacientes adultos, en buenas condiciones generales se les practicó cirugía de la columna vertebral o histerectomía abdominal bajo anestesia general balanceada. Se constató disminución franca de la diuresis transoperatoria a pesar de la adecuada estabilidad cardiocirculatoria y persfusión de líquidos parenterales. Posiblemente el procedimiento anestésico quirúrgico, la posición prona y la comprensión intra-abdominal determinaron cambios en los mecanismos intrínsecos y extrínsicos que controlan el flujo sanguíneo renal y la velocidad de filtración glomerular siendo indispensable la vigilancia continua de la diuresis horaria y procurar protección renal en el periodo trans-anestésico

Water electrolyte homeostasis in acute bronchiolitis.

Children with acute bronchiolitis frequently require hospitalization and parenteral fluid therapy. Water retention due to impaired renal water excretion has been described in several pulmonary conditions in children. We studied 20 infants (3.6 +/- 2.9 months), hospitalized consecutively for acute bronchiolitis for water and electrolyte changes during the acute stage and compared them to those on recovery. Serum sodium and plasma osmolality, urinary sodium and osmolality were measured in all infants. Ten infants each were assigned alternatively to study body water compartment or renal water handling (water load excretion and free water excretion capacity) on the day of hospitalization and after recovery. Mean ( +/- SD) value of serum sodium of the infants at admission was 132.7 +/- 7.2 mEq/L which increased to 137.1 +/- 5.4 mEq/L on recovery (p < 0.05). Plasma osmolality changed from 284 +/- 14 mOsm/kg at admission to 294 +/- 10 mOsm/kg at recovery (p < 0.05). There was a significant decrease in urinary sodium from 54 +/- 39 mEq/L to 20 +/- 18 mEq/L and urinary osmolality from 415 +/- 213 mOsm/kg to 252 +/- 204 mOsm/kg at admission and at recovery, respectively. All 10 infants showed significant increase in total body water (mean +/- SD; 22.8 +/- 7.5 ml/kg) at admission as compared to that at recovery. The total body water (TBW) excess was mainly in extracellular water compartment (16.3 +/- 3.6 ml/kg). Seven of 10 infants had significant impairment in renal water excretion. Increase in maximum free water clearance of these 7 infants on recovery was 0.69 +/- 0.27 ml/min, i.e., 15 times more than that at admission. It is concluded that bronchiolitis of infancy is characterized by water retention which is caused by impaired renal water excretion. In the management of severe bronchiolitis careful attention to fluid therapy is mandatory; liberal fluid therapy may lead to water intoxication.

Orina de color y cantidad anormal / Urine of abnormal color and quantity

Siempre que sea posible es aconsejable observar la orina como parte del examen físico (micción en el pañal, micción espontánea en el lactante, muestra ex profeso y datos de información anamnésticos en el niño mayor). Normalmente la orina es de color amarillo ámbar más o menos pálido con variaciones del matiz por circunstancias diversas. Recién emitida es límpida y transparente

Ultrafiltración durante circulación extracorpórea / Ultrafiltration during extracorporeal circulation

Se comunica la primera experiencia del servicio en el uso de ultrafiltración durante circulación extracorpórea (CEC) en siete pacientes, tres hombres y cuatro mujeres de edades entre 23 y 69 años, que fueron sometidos a cirugía de urgencia por patología valvular. A su ingreso a pabellón seis presentaban insuficiencia cardíaca refractaria y el restante, anemia hemolítica. Cinco tenían evidencia preoperatoria de disfunción renal. En todos pudo realizarse ultrafiltración, extrayéndose en promedio 2.121 ml de volumen (900-3.850). El balance hídrico final promedio fue de 1.340 ml (-650 a 3.470). Los valores promedio de hematocrito pre-CEC, intra-CEC fueron 30 por ciento, 16,8 por ciento y 24,3 por ciento respectivamente. En la evolución postoperatoria, 6 pacientes presentaron insuficiencia renal aguda oligúrica, requiriendo diálisis cuatro de ellos. Cinco fueron dados de alta en buenas condiciones en un promedio de 32 días (18 a 70). Dos fallecieron alrededor del 11º día, uno por necrosis mesentérica y el otro por shock séptico secundario a endocarditis bacteriana subaguda. La ultrafiltración es una técnica fácil de implementar durante CEC