Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 82
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Int J Sports Med ; 40(11): 711-716, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31434137

RESUMO

The purpose of this study was to evaluate whether NaHCO3, administered via a 9-h stacked loading protocol (i.e. repeated supplementation with small doses in order to obtain a gradual increase in blood [HCO3 -]), has an ergogenic effect on repeated all-out exercise. Twelve physically active males were randomly assigned to receive either NaHCO3 (BIC) or placebo (PL) in a double-blind cross-over design. NaHCO3 supplementation was divided in three identical 3-h cycles: a 6.3 g bolus at the start, followed by 2.1 g doses at +1-h and +2-h, yielding a total NaHCO3 intake of 0.4 g·kg-1 BM over 9-h. At the end of each cycle, participants performed 2-min all-out cycling. Capillary blood samples were analyzed for [HCO3 -], pH and [La-]. Pre-exercise blood [HCO3 -] in PL decreased from 25.6±0.2 mmol·L-1 in bout 1 to 23.6±0.2 mmol·L-1 in bout 4, while increasing from 25.5±0.2 to 31.2±0.4 mmol·L-1 in BIC (P<0.05). Concomitantly, pre-exercise pH values gradually decreased in PL (from 7.41±0.00 to 7.39±0.01) and increased in BIC (from 7.41±0.01 to 7.47±0.01; P<0.05). Mean power output of the four bouts was higher in BIC (428±20 W) than in PL (420±20 W; P<0.05). The ergogenic effect on repeated all-out exercise occurred in the absence of gastrointestinal distress.


Assuntos
Desempenho Atlético/fisiologia , Substâncias para Melhoria do Desempenho/administração & dosagem , Bicarbonato de Sódio/administração & dosagem , Estudos Cross-Over , Método Duplo-Cego , Esquema de Medicação , Teste de Esforço , Gastroenteropatias/induzido quimicamente , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Substâncias para Melhoria do Desempenho/efeitos adversos , Substâncias para Melhoria do Desempenho/sangue , Bicarbonato de Sódio/efeitos adversos , Bicarbonato de Sódio/sangue , Adulto Jovem
2.
J Sports Sci ; 37(13): 1464-1471, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30668281

RESUMO

This study investigated the effects of two separate doses of sodium bicarbonate (NaHCO3) on 4 km time trial (TT) cycling performance and post-exercise acid base balance recovery in hypoxia. Fourteen club-level cyclists completed four cycling TT's, followed by a 40 min passive recovery in normobaric hypoxic conditions (FiO2 = 14.5%) following one of either: two doses of NaHCO3 (0.2 g.kg-1 BM; SBC2, or 0.3 g.kg-1 BM; SBC3), a taste-matched placebo (0.07 g.kg-1 BM sodium chloride; PLA), or a control trial in a double-blind, randomized, repeated-measures and crossover design study. Compared to PLA, TT performance was improved following SBC2 (p = 0.04, g = 0.16, very likely beneficial), but was improved to a greater extent following SBC3 (p = 0.01, g = 0.24, very likely beneficial). Furthermore, a likely benefit of ingesting SBC3 over SBC2 was observed (p = 0.13, g = 0.10), although there was a large inter-individual variation. Both SBC treatments achieved full recovery within 40 min, which was not observed in either PLA or CON following the TT. In conclusion, NaHCO3 improves 4 km TT performance and acid base balance recovery in acute moderate hypoxic conditions, however the optimal dose warrants an individual approach.


Assuntos
Equilíbrio Ácido-Base/efeitos dos fármacos , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Substâncias para Melhoria do Desempenho/administração & dosagem , Bicarbonato de Sódio/administração & dosagem , Adolescente , Adulto , Estudos Cross-Over , Método Duplo-Cego , Feminino , Gastroenteropatias/induzido quimicamente , Frequência Cardíaca , Humanos , Concentração de Íons de Hidrogênio , Hipóxia , Masculino , Oxigênio/sangue , Percepção , Substâncias para Melhoria do Desempenho/efeitos adversos , Substâncias para Melhoria do Desempenho/sangue , Esforço Físico , Bicarbonato de Sódio/efeitos adversos , Bicarbonato de Sódio/sangue , Adulto Jovem
3.
J Sports Sci ; 37(7): 762-771, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30319077

RESUMO

The aim of this study was to perform a systematic review and meta-analysis on the acute and chronic effects of sodium bicarbonate (NaHCO3) ingestion on Wingate performance. Following a search through PubMed, Scopus and Web of Science, 9 studies were found meeting inclusion criteria (6 acute and 3 chronic). Random-effects meta-analysis of standardized mean difference (SMD) for peak and mean power was performed. Study quality was assessed using the QualSyst. Results of the meta-analysis showed that acute ingestion of NaHCO3 did not improve Wingate test peak (weighted average effect size Hedges's g = 0.02, 95%CI: - 0.19 to 0.23, P = 0.87) or mean power (weighted average effect size Hedges's g = 0.15, 95%CI: -0.06 to 0.36, P = 0.92). However, chronic ingestion of NaHCO3 improved Wingate test peak (weighted average effect size Hedges's g = 1.21, 95%CI: 0.83 to 1.42, P = 0.001) and mean power (weighted average effect size Hedges's g = 1.26, 95%CI: 0.96 to 1.56, P = 0.001). Quality assessment of selected articles was classified as strong. This meta-analysis provides evidence that chronic, but not acute, ingestion of NaHCO3 increases both Wingate test peak and mean power.


Assuntos
Acidose/prevenção & controle , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Bicarbonato de Sódio/administração & dosagem , Administração Oral , Esquema de Medicação , Metabolismo Energético/efeitos dos fármacos , Humanos , Fadiga Muscular/fisiologia , Bicarbonato de Sódio/sangue
4.
J Sci Med Sport ; 22(3): 335-341, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30170952

RESUMO

OBJECTIVES: The aim of the present study was to test the effect of sodium bicarbonate (NaHCO3-) ingestion on performance during a simulated competition on a Bicycle Motocross (BMX) track. DESIGN: Double-blind cross-over study. METHODS: Twelve elite male BMX cyclists (age: 19.2±3.4 years; height: 174.2±5.3cm; body mass: 72.4±8.4kg) ingested either NaHCO3- (0.3g.kg-1 body weight) or placebo 90min prior to exercise. The cyclists completed three races in a BMX Olympic track interspersed with 15min of recovery. Blood samples were collected to assess the blood acid-base status. Performance, cardiorespiratory, heart rate variability (HRV) as well as subjective variables were assessed. RESULTS: The main effect of condition (NaHCO3- vs. placebo) was observed in pH, bicarbonate concentration and base excess (p<0.05), with a significant blood alkalosis. No changes were found in time, peak velocity and time to peak velocity for condition (p>0.05). The HRV analysis showed a significant effect of NaHCO3- ingestion, expressed by the rMSSD30 (root mean square of the successive differences) (p<0.001). There was no effect of condition on oxygen uptake, carbon dioxide production, or pulmonary ventilation (p>0.05). Finally, there was no effect of condition for any subjective scale (p>0.05). CONCLUSIONS: We present here the first field condition study to investigate the effect of bicarbonate ingestion over performance in BMX discipline. The results showed that NaHCO3--induced alkalosis did not improve performance in a simulated BMX competition in elite BMX cyclists, although future studies should consider the effects of NaHCO3- on autonomic function as a component of recovery.


Assuntos
Alcalose/sangue , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Bicarbonato de Sódio/administração & dosagem , Adolescente , Alcalose/induzido quimicamente , Estudos Cross-Over , Método Duplo-Cego , Frequência Cardíaca , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Bicarbonato de Sódio/sangue , Adulto Jovem
5.
Am J Physiol Renal Physiol ; 314(5): F985-F991, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29357423

RESUMO

Greater H+ retention in animal models of chronic kidney disease (CKD) mediates faster glomerular filtration rate (GFR) decline and dietary H+ reduction slows eGFR decline in CKD patients with reduced eGFR and H+ retention due to the high acid (H+) diets of developed societies. We examined if H+ retention in CKD is inversely associated with estimated GFR (eGFR) using cross-sectional and longitudinal analysis of individuals with CKD stage 1 (>90 ml·min- 1·1.73 m-2), CKD stage 2 (60-89 ml/min per 1.73 m2), and CKD stage 3 (30-59 ml·min- 1·1.73 m-2) eGFR. H+ retention was assessed using the difference between observed and expected plasma total CO2 2 h after 0.5 meq/kg body wt oral NaHCO3. H+ retention was higher in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.02) at baseline and 5 yr, and was higher in CKD 2 vs. CKD 1 ( P < 0.01) at 10 yr. All groups had lower eGFR at subsequent time points ( P < 0.01) but H+ retention was not different among the three time points for CKD 1. By contrast, eGFR decrease was associated with higher H+ retention in CKD 2 at 5 yr ( P = 0.04) and 10 yr ( P < 0.01) and with higher H+ retention in CKD 3 at 5 yr ( P < 0.01). Yearly eGFR decline rate was faster in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.01). The data show that H+ retention is inversely associated with eGFR, with faster eGFR decline, and support the need for greater dietary H+ reduction therapy for CKD individuals with lower eGFR.


Assuntos
Equilíbrio Ácido-Base , Acidose/fisiopatologia , Taxa de Filtração Glomerular , Rim/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Equilíbrio Ácido-Base/efeitos dos fármacos , Acidose/sangue , Acidose/diagnóstico , Acidose/tratamento farmacológico , Ácidos/sangue , Administração Oral , Adulto , Estudos Transversais , Progressão da Doença , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Rim/efeitos dos fármacos , Rim/metabolismo , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prognóstico , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/diagnóstico , Índice de Gravidade de Doença , Bicarbonato de Sódio/administração & dosagem , Bicarbonato de Sódio/sangue , Fatores de Tempo
6.
Med Sci Sports Exerc ; 49(9): 1899-1910, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28398947

RESUMO

PURPOSE: This study aimed to determine the effect of preexercise metabolic acidosis and alkalosis on power output (PO) and aerobic and anaerobic energy expenditure during a 4-km cycling time trial (TT). METHODS: Eleven recreationally trained cyclists (V˙O2peak 54.1 ± 9.3 mL·kg·min) performed a 4-km TT 100 min after ingesting in a double-blind matter 0.15 g·kg of body mass of ammonium chloride (NH4Cl, acidosis), 0.3 g·kg of sodium bicarbonate (NaHCO3, alkalosis), or 0.15 g·kg of CaCO3 (placebo). A preliminary study (n = 7) was conducted to establish the optimal doses to promote the desirable preexercise blood pH alterations without gastrointestinal distress. Data for PO, aerobic and anaerobic energy expenditure, and blood and respiratory parameters were averaged for each 1 km and compared between conditions using two-way repeated-measures ANOVA (condition and distance factors). Gastrointestinal discomfort was analyzed qualitatively. RESULTS: Compared with placebo (pH 7.37 ± 0.02, [HCO3]: 27.5 ± 2.6 mmol·L), the NaHCO3 ingestion resulted in a preexercise blood alkalosis (pH +0.06 ± 0.04, [HCO3]: +4.4 ± 2.0 mmol·L, P < 0.05), whereas NH4Cl resulted in a blood acidosis (pH -0.05 ± 0.03, [HCO3]: -4.8 ± 2.1 mmol·L, P < 0.05). Anaerobic energy expenditure rate and PO were reduced throughout the trial in NH4Cl compared with placebo and NaHCO3, resulting in a lower total anaerobic work and impaired performance (P < 0.05). Plasma lactate, V˙CO2, and end-tidal CO2 partial pressure were lower and the V˙E/V˙CO2 higher throughout the trial in NH4Cl compared with placebo and NaHCO3 (P < 0.05). There was no difference between NaHCO3 and placebo for any of these variables (P > 0.05). Minimal gastrointestinal distress was noted in all conditions. CONCLUSION: Preexercise acidosis, but not alkalosis, affects anaerobic metabolism and PO during a 4-km cycling TT.


Assuntos
Acidose/fisiopatologia , Alcalose/fisiopatologia , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Acidose/complicações , Adulto , Alcalose/complicações , Cloreto de Alumínio , Compostos de Alumínio/sangue , Cloretos/sangue , Método Duplo-Cego , Gastroenteropatias/etiologia , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Bicarbonato de Sódio/sangue , Fatores de Tempo
7.
Int J Sport Nutr Exerc Metab ; 27(3): 271-278, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27834492

RESUMO

When ingested alone, beetroot juice and sodium bicarbonate are ergogenic for high-intensity exercise performance. This study sought to determine the independent and combined effects of these supplements. Eight endurance trained (VO2max 65 mL·kg·min-1) male cyclists completed four × 4-km time trials (TT) in a doubleblind Latin square design supplementing with beetroot crystals (BC) for 3 days (15 g·day-1 + 15 g 1 h before TT, containing 300 mg nitrate per 15 g), bicarbonate (Bi 0.3 g·kg-1 body mass [BM] in 5 doses every 15 min from 2.5 h before TT); BC+Bi or placebo (PLA). Subjects completed TTs on a Velotron cycle ergometer under standardized laboratory conditions. Plasma nitrite concentrations were significantly elevated only in the BC+Bi trial before the TT (1520 ± 786 nmol·L-1) compared with baseline (665 ± 535 nmol·L-1, p = .02) and the Bi and PLA conditions (Bi: 593 ± 203 nmol·L-1, p < .01; PLA: 543 ± 369 nmol·L-1, p < .01). Plasma nitrite concentrations were not elevated in the BC trial before the TT (1102 ± 218 nmol·L-1) compared with baseline (975 ± 607 nmol·L-1, p > .05). Blood bicarbonate concentrations were increased in the BC+Bi and Bi trials before the TT (BC+Bi: 30.9 ± 2.8 mmol·L-1; Bi: 31.7 ± 1.1 mmol·L-1). There were no differences in mean power output (386-394 W) or the time taken to complete the TT (335.8-338.1 s) between any conditions. Under the conditions of this study, supplementation was not ergogenic for 4-km TT performance.


Assuntos
Desempenho Atlético , Beta vulgaris , Ciclismo/fisiologia , Substâncias para Melhoria do Desempenho/farmacologia , Bicarbonato de Sódio/farmacologia , Fenômenos Fisiológicos da Nutrição Esportiva , Adulto , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Masculino , Nitratos/administração & dosagem , Nitratos/sangue , Bicarbonato de Sódio/sangue
8.
Int Urol Nephrol ; 49(1): 49-53, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27785747

RESUMO

PURPOSE: To evaluate the necessity of chronic alkali therapy in non-complicated orthotopic ileal neobladders with normal renal function. MATERIALS AND METHODS: This is a prospective study that included 200 male patients who underwent radical cystectomy and ileal W neobladder for invasive bladder carcinoma between January 1993 and December 2013. The studied patients included 100 consecutive patients who were maintained on regular alkali therapy since surgery and 100 consecutive patients who stopped the use of alkali treatment after initial 3 months postoperative with minimum postoperative observation time of 1 year. All patients had satisfactory function of the reservoirs with normal upper tract. The patients were subjected to blood analysis for creatnine, electrolytes, pH and bicarbonate and urine chemical analysis. The study also included 40 healthy male age-matched volunteers who served as a control group. RESULTS: Both groups were comparable as regard age, BMI, follow-up period and surgical technique. There were no significant differences between both groups as regard serum creatnine, electrolytes blood pH and bicarbonate and the mean values were within normal range; however, the neobladder patients are still toward the acidotic side in comparison to healthy volunteers. Also there were no significant differences between both groups of patients as regard urine pH and excretion of electrolytes, calcium, phosphorus and creatnine. CONCLUSION: Patients with non-complicated ileal neobladders with normal upper tract who were not maintained on alkali prophylaxis for long period have a compensated acid base status. Therefore, the prolonged alkali prophylaxis is not mandatory.


Assuntos
Acidose/prevenção & controle , Carcinoma/cirurgia , Bicarbonato de Sódio/administração & dosagem , Estruturas Criadas Cirurgicamente/efeitos adversos , Neoplasias da Bexiga Urinária/cirurgia , Bexiga Urinária/cirurgia , Derivação Urinária/efeitos adversos , Acidose/sangue , Acidose/etiologia , Idoso , Cistectomia , Seguimentos , Humanos , Concentração de Íons de Hidrogênio , Íleo/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Bicarbonato de Sódio/sangue , Urinálise
9.
Am J Emerg Med ; 34(11): 2167-2171, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27599399

RESUMO

OBJECTIVES: This study examined the pH, lactate dehydrogenase (LDH), and heart rate values on the first day of hospitalization in patients with a prediagnosis of sepsis and biomarkers that may predict mortality. METHODS: Patients hospitalized in an emergency intensive care unit with a diagnosis of systemic inflammatory response syndrome were classified as having sepsis (n = 28), septic shock (n = 8), or severe sepsis (n = 8) according to International Sepsis Guidelines (old criteria). Forty-four patients were classified as having sepsis (n = 4), septic shock (n = 30), or infection (n = 10) according to The Third International Consensus Definitions for Sepsis and Septic Shock (new criteria). The effects of these patients' laboratory values on survival between groups were compared. Significant values were evaluated by χ2 automatic interaction detection analysis. RESULTS: When the patients were categorized according to the new classification criteria, there was an increase in the number of septic shock patients and a decrease in the number of sepsis patients. In addition, 10 patients were removed from the sepsis category. There was a significant difference between ex and discharged patients in terms of heart rate, pH, sodium bicarbonate, lactate, and LDH (P= .007, P= .002, P= .034, P= .009, and P= .002, respectively). Based on a χ2 automatic interaction detection analysis of the significant values, pH, LDH, and heart rate were prominent predictors of prognosis. CONCLUSIONS: Systemic pH, LDH, and heart rate values may be used to determine the best time to discharge patients from intensive care to other, more affordable hospital units.


Assuntos
Ensaios Enzimáticos Clínicos , Frequência Cardíaca , L-Lactato Desidrogenase/sangue , Sepse/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Hospitalização , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Guias de Prática Clínica como Assunto , Valor Preditivo dos Testes , Prognóstico , Sepse/fisiopatologia , Choque Séptico/diagnóstico , Choque Séptico/enzimologia , Choque Séptico/fisiopatologia , Bicarbonato de Sódio/sangue , Taxa de Sobrevida
10.
Nefrología (Madr.) ; 36(4): 347-353, jul.-ago. 2016. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-155392

RESUMO

Hyperchloremia is a common electrolyte disorder that is associated with a diverse group of clinical conditions. The kidney plays an important role in the regulation of chloride concentration through a variety of transporters that are present along the nephron. Nevertheless, hyperchloremia can occur when water losses exceed sodium and chloride losses, when the capacity to handle excessive chloride is overwhelmed, or when the serum bicarbonate is low with a concomitant rise in chloride as occurs with a normal anion gap metabolic acidosis or respiratory alkalosis. The varied nature of the underlying causes of the hyperchloremia will, to a large extent, determine how to treat this electrolyte disturbance (AU)


La hipercloremia es una alteración electrolítica frecuente que se asocia a una serie de distintos trastornos clínicos. El riñón desempeña una función importante en la regulación de la concentración de cloruro a través de diversos transportadores que se encuentran a lo largo de la nefrona. Sin embargo, puede aparecer hipercloremia cuando la pérdida hídrica sea mayor que la de sodio y cloruro; cuando se sobrepase la capacidad de excretar el cloruro en exceso; o cuando la concentración sérica de bicarbonato sea baja y al mismo tiempo haya un aumento de cloruro, como sucede en la acidosis metabólica con brecha aniónica normal o en la alcalosis respiratoria. La heterogénea naturaleza de las causas subyacentes de la hipercloremia determinará, en gran medida, el modo de tratar esta alteración electrolítica (AU)


Assuntos
Humanos , Desequilíbrio Hidroeletrolítico/fisiopatologia , Bicarbonato de Sódio/sangue , Cloretos/sangue , Insuficiência Renal/fisiopatologia , Taxa de Filtração Glomerular , Fatores de Risco
11.
Int J Sport Nutr Exerc Metab ; 26(5): 445-453, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27098290

RESUMO

To defend against hydrogen cation accumulation and muscle fatigue during exercise, sodium bicarbonate (NaHCO3) ingestion is commonplace. The individualized dose-response relationship between NaHCO3 ingestion and blood biochemistry is unclear. The present study investigated the bicarbonate, pH, base excess and sodium responses to NaHCO3 ingestion. Sixteen healthy males (23 ± 2 years; 78.6 ± 15.1 kg) attended three randomized order-balanced, nonblinded sessions, ingesting a single dose of either 0.1, 0.2 or 0.3 g·kg-1BM of NaHCO3 (Intralabs, UK). Fingertip capillary blood was obtained at baseline and every 10 min for 1 hr, then every 15 min for a further 2 hr. There was a significant main effect of both time and condition for all assessed blood analytes (p ≤ .001). Blood analyte responses were significantly lower following 0.1 g·kg-1BM compared with 0.2 g·kg-1BM; bicarbonate concentrations and base excess were highest following ingestion of 0.3 g·kg-1BM (p ≤ .01). Bicarbonate concentrations and pH significantly increased from baseline following all doses; the higher the dose the greater the increase. Large interindividual variability was shown in the magnitude of the increase in bicarbonate concentrations following each dose (+2.0-5; +5.1-8.1; and +6.0-12.3 mmol·L-1 for 0.1, 0.2 and 0.3 g·kg-1BM) and in the range of time to peak concentrations (30-150; 40-165; and 75-180 min for 0.1, 0.2 and 0.3 g·kg-1BM). The variability in bicarbonate responses was not affected by normalization to body mass. These results challenge current practices relating to NaHCO3 supplementation and clearly show the need for athletes to individualize their ingestion protocol and trial varying dosages before competition.


Assuntos
Exercício , Bicarbonato de Sódio/administração & dosagem , Bicarbonato de Sódio/sangue , Adulto , Atletas , Desempenho Atlético , Índice de Massa Corporal , Estudos Cross-Over , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Humanos , Concentração de Íons de Hidrogênio , Individualidade , Modelos Lineares , Masculino , Fadiga Muscular , Adulto Jovem
12.
J Anesth ; 30(3): 391-6, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26961820

RESUMO

PURPOSE: The recommended method for elucidating the effects of strong ions other than lactate on acid-base balance is to calculate the non-lactate strong ion difference (SIDnl). A relationship between HCO3 (-) and SIDnl in hyperchloremic patients has already been demonstrated; in the present study, the relationships between SIDnl, the apparent strong ion difference (SIDa), and mortality at intensive care unit (ICU) admission were investigated. METHODS: In our two-center study, 2691 patients admitted to the ICU were retrospectively evaluated, including 1069 critically ill patients. These patients were divided into three subgroups according to their SIDnl levels at admission to the ICU: low (<38 mmol L(-1)), normal (38-40 mmol L(-1)), and high (>40 mmol L(-1)). Patient age, gender, diagnosis, blood gas values, length of ICU stay, and mortality were recorded. RESULTS: The low-SIDnl group included 768 patients (71.8 %), the normal-SIDnl group consisted of 127 patients (11.9 %), and the high-SIDnl group contained 174 patients (16.3 %). There was no significant difference in lactate levels among the SIDnl groups (p = 0.635). In a multivariate logistic regression model, likelihood of mortality was increased 1.24-fold (1.20-1.28), 2.56-fold (1.61-4.08) and 2.55-fold (1.003-6.47) by APACHE II, lactate level ≥2mmol L(-) and low SIDnl (p < 0.001, p < 0.001, and p = 0.049, respectively). CONCLUSIONS: SIDnl can be used to determine the effects of strong ions other than lactate on SIDa values and acid-base balance. Furthermore, a low SIDnl at ICU admission can be a prognostic indicator of mortality.


Assuntos
Desequilíbrio Ácido-Base/sangue , Desequilíbrio Ácido-Base/terapia , Íons/sangue , APACHE , Desequilíbrio Ácido-Base/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Cloretos/sangue , Cuidados Críticos , Estado Terminal , Feminino , Mortalidade Hospitalar , Humanos , Ácido Láctico/sangue , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Bicarbonato de Sódio/sangue
13.
Sports Med ; 45 Suppl 1: S71-81, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26553493

RESUMO

Intramuscular acidosis is a contributing factor to fatigue during high-intensity exercise. Many nutritional strategies aiming to increase intra- and extracellular buffering capacity have been investigated. Among these, supplementation of beta-alanine (~3-6.4 g/day for 4 weeks or longer), the rate-limiting factor to the intramuscular synthesis of carnosine (i.e. an intracellular buffer), has been shown to result in positive effects on exercise performance in which acidosis is a contributing factor to fatigue. Furthermore, sodium bicarbonate, sodium citrate and sodium/calcium lactate supplementation have been employed in an attempt to increase the extracellular buffering capacity. Although all attempts have increased blood bicarbonate concentrations, evidence indicates that sodium bicarbonate (0.3 g/kg body mass) is the most effective in improving high-intensity exercise performance. The evidence supporting the ergogenic effects of sodium citrate and lactate remain weak. These nutritional strategies are not without side effects, as gastrointestinal distress is often associated with the effective doses of sodium bicarbonate, sodium citrate and calcium lactate. Similarly, paresthesia (i.e. tingling sensation of the skin) is currently the only known side effect associated with beta-alanine supplementation, and it is caused by the acute elevation in plasma beta-alanine concentration after a single dose of beta-alanine. Finally, the co-supplementation of beta-alanine and sodium bicarbonate may result in additive ergogenic gains during high-intensity exercise, although studies are required to investigate this combination in a wide range of sports.


Assuntos
Acidose/prevenção & controle , Suplementos Nutricionais , Exercício/fisiologia , Músculo Esquelético/metabolismo , Compostos de Cálcio/administração & dosagem , Compostos de Cálcio/efeitos adversos , Compostos de Cálcio/metabolismo , Citratos/administração & dosagem , Citratos/efeitos adversos , Citratos/metabolismo , Suplementos Nutricionais/efeitos adversos , Metabolismo Energético , Líquido Extracelular/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular/metabolismo , Lactatos/administração & dosagem , Lactatos/efeitos adversos , Lactatos/metabolismo , Fadiga Muscular , Bicarbonato de Sódio/administração & dosagem , Bicarbonato de Sódio/efeitos adversos , Bicarbonato de Sódio/sangue , Citrato de Sódio , Lactato de Sódio/administração & dosagem , Lactato de Sódio/efeitos adversos , Lactato de Sódio/metabolismo , beta-Alanina/administração & dosagem , beta-Alanina/efeitos adversos , beta-Alanina/metabolismo
15.
Am J Emerg Med ; 33(9): 1134-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26027886

RESUMO

BACKGROUND: Biomarkers such as serum lactate, anion gap (AG), and base excess (BE) have been shown to be of use in determining shock in patients with seemingly normal vital signs. We seek to determine if these biomarkers can be used interchangeably in patients with trauma in the emergency setting based on their test characteristics and correlation to each other. METHODS: A prospective observational cohort study was undertaken at an urban level 1 trauma center. Baseline vital signs, point-of-care BE, AG, and serum lactate were recorded in all patients who presented for trauma. Correlation was determined by linear regression model. Overall test characteristics and relative risk were calculated. RESULTS: One hundred patients were enrolled. The median age was 30 years (interquartile range, 24-42 years), and 89% were male. Fifty-three percent of injuries were blunt trauma. Pearson correlation of serum lactate to BE was -0.81 (r(2) = 0.66; 95% confidence interval [CI], 0.53-0.75; P < .001), that of BE to AG was -0.71 (r(2) = 0.5; 95% CI, -0.80 to -0.57; P < .01), and that for serum lactate to AG was 0.71 (r(2) = 0.5; 95% CI, 0.57-0.80; P < .01). CONCLUSIONS: This study demonstrates that the biomarkers have similar test characteristics which may make them interchangeable as indicators for the presence of occult shock in patients with trauma. Lactate and BE correlate well with each other; however, AG was not as strongly correlated with either.


Assuntos
Equilíbrio Ácido-Base , Serviço Hospitalar de Emergência , Ácido Láctico/sangue , Choque Traumático/diagnóstico , Bicarbonato de Sódio/sangue , Adulto , Biomarcadores/sangue , Feminino , Humanos , Concentração de Íons de Hidrogênio , Modelos Lineares , Masculino , Estudos Prospectivos , Curva ROC , Sinais Vitais , Adulto Jovem
16.
J Int Soc Sports Nutr ; 12: 25, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26097440

RESUMO

BACKGROUND: Sodium bicarbonate intake has been shown to improve exercise tolerance, but the effects on high-intensity intermittent exercise are less clear. Thus, the aim of the present study was to determine the effect of sodium bicarbonate intake on Yo-Yo intermittent recovery test level 2 performance in trained young men. METHOD: Thirteen men aged 23 ± 1 year (height: 180 ± 2 cm, weight: 78 ± 3 kg; VO2max: 61.3 ± 3.3 mlO2 · kg(-1) · min(-1); means ± SEM) performed the Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) on two separate occasions in randomized order with (SBC) and without (CON) prior intake of sodium bicarbonate (0.4 g · kg(-1) body weight). Heart rate and rating of perceived exertion (RPE) were measured during the test and venous blood samples were taken frequently. RESULTS: Yo-Yo IR2 performance was 14 % higher (P = 0.04) in SBC than in CON (735 ± 61 vs 646 ± 46 m, respectively). Blood pH and bicarbonate were similar between trials at baseline, but higher (P = 0.003) immediately prior to the Yo-Yo IR2 test in SBC than in CON (7.44 ± 0.01 vs 7.32 ± 0.01 and 33.7 ± 3.2 vs 27.3 ± 0.6 mmol · l(-1), respectively). Blood lactate was 0.9 ± 0.1 and 0.8 ± 0.1 mmol · l(-1) at baseline and increased to 11.3 ± 1.4 and 9.4 ± 0.8 mmol · l(-1) at exhaustion in SBC and CON, respectively, being higher (P = 0.03) in SBC. Additionally, peak blood lactate was higher (P = 0.02) in SBC than in CON (11.7 ± 1.2 vs 10.2 ± 0.7 mmol · l(-1)). Blood glucose, plasma K(+) and Na(+) were not different between trials. Peak heart rate reached at exhaustion was 197 ± 3 and 195 ± 3 bpm in SBC and CON, respectively, with no difference between conditions. RPE was 7% lower (P = 0.003) in SBC than in CON after 440 m, but similar at exhaustion (19.3 ± 0.2 and 19.5 ± 0.2). CONCLUSION: In conclusion, high-intensity intermittent exercise performance is improved by prior intake of sodium bicarbonate in trained young men, with concomitant elevations in blood alkalosis and peak blood lactate levels, as well as lowered rating of perceived exertion.


Assuntos
Resistência Física/efeitos dos fármacos , Bicarbonato de Sódio/administração & dosagem , Alcalose/sangue , Glicemia/metabolismo , Peso Corporal , Estudos Cross-Over , Fadiga/sangue , Fadiga/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Esforço Físico/efeitos dos fármacos , Potássio/sangue , Método Simples-Cego , Sódio/sangue , Bicarbonato de Sódio/sangue , Adulto Jovem
17.
Am J Kidney Dis ; 66(3): 469-78, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26015276

RESUMO

BACKGROUND: To date, very few studies have been carried out on the associations of pre- and postdialysis acid-base parameters with mortality in hemodialysis patients. STUDY DESIGN: An observational study including cross-sectional and 1-year analyses. SETTING & PARTICIPANTS: Data from the renal registry of the Japanese Society of Dialysis Therapy (2008-2009), including 15,132 dialysis patients 16 years or older. PREDICTOR: Predialysis pH<7.30, 7.30 to 7.34 (reference), 7.35 to 7.39, or ≥7.40 (1,550, 4,802, 6,023, and 2,757 patients, respectively); predialysis bicarbonate level < 18.0, 18.0 to 21.9 (reference), 22.0 to 25.9, or ≥26.0 mEq/L (2,724, 7,851, 4,023, and 534 patients, respectively); postdialysis pH<7.40, 7.40 to 7.44, 7.45 to 7.49 (reference), or ≥7.50 (2,114, 5,331, 4,975, and 2,712 patients, respectively); and postdialysis bicarbonate level < 24.0, 24.0 to 25.9, 26.0 to 27.9 (reference), or ≥28.0 mEq/L (5,087, 4,330, 3,451, and 2,264 patients, respectively). OUTCOMES: All-cause and cardiovascular (CV) mortality during the 1-year follow-up. MEASUREMENTS: HRs were estimated using unadjusted models and models adjusted for age, sex, dialysis vintage, history of CV disease, diabetes, weight gain ratio, body mass index, calcium-phosphorus product, serum albumin level, serum total cholesterol level, blood hemoglobin level, single-pool Kt/V, and normalized protein catabolic rate. RESULTS: Of 15,132 patients, during follow-up, 1,042 died of all causes, including 408 CV deaths. In the adjusted analysis for all-cause mortality, HRs compared to the reference group were significantly higher in patients with predialysis pH≥7.40 (HR, 1.36; 95% CI, 1.13-1.65) and postdialysis pH<7.40 (HR, 1.22; 95% CI, 1.00-1.49). Predialysis pH≥7.40 was also associated with higher risk of CV mortality (HR, 1.34; 95% CI, 1.01-1.79). No association of pre- or postdialysis bicarbonate level with all-cause and CV mortality was observed. LIMITATIONS: Single measurements of acid-base parameters, short duration of follow-up, small number of CV deaths. CONCLUSIONS: Predialysis pH≥7.40 was associated with significantly elevated risk of all-cause and CV mortality. However, pre- and postdialysis bicarbonate levels were not associated with all-cause and CV mortality. Predialysis pH may be the most appropriate reference for accurate correction of metabolic acidosis in dialysis patients.


Assuntos
Doenças Cardiovasculares/mortalidade , Falência Renal Crônica/mortalidade , Diálise Renal/mortalidade , Bicarbonato de Sódio/sangue , Idoso , Causas de Morte , Feminino , Humanos , Concentração de Íons de Hidrogênio , Falência Renal Crônica/terapia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Medição de Risco
18.
Pediatr Nephrol ; 30(6): 873-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25085611

RESUMO

Metabolic acidosis (MA) is relatively common in patients with chronic kidney disease (CKD) particularly in stages 4 and 5. It is assumed to play a contributory role in the development of several complications including bone disease, skeletal muscle wasting, altered protein synthesis, and degradation. Recent evidence also suggests that even mild acidosis might play a role in progressive glomerular filtration rate loss. Experimental and clinical studies suggest that correction of acidosis by alkali therapy attenuates these complications and improves quality of life. Despite several recent small and single-center studies supporting this notion, more robust evidence is required with regard to the long-term benefits of alkali therapy, type of alkali supplements, and the optimal level of serum bicarbonate.


Assuntos
Acidose/tratamento farmacológico , Álcalis/uso terapêutico , Qualidade de Vida , Insuficiência Renal Crônica/tratamento farmacológico , Bicarbonato de Sódio/uso terapêutico , Acidose/sangue , Acidose/etiologia , Acidose/psicologia , Fatores Etários , Álcalis/efeitos adversos , Animais , Progressão da Doença , Humanos , Concentração de Íons de Hidrogênio , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/psicologia , Fatores de Risco , Bicarbonato de Sódio/efeitos adversos , Bicarbonato de Sódio/sangue , Resultado do Tratamento
19.
Eur J Appl Physiol ; 114(8): 1715-24, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24832191

RESUMO

INTRODUCTION: ß-alanine (BAl) and NaHCO3 (SB) ingestion may provide performance benefits by enhancing concentrations of their respective physiochemical buffer counterparts, muscle carnosine and blood bicarbonate, counteracting acidosis during intense exercise. This study examined the effect of BAl and SB co-supplementation as an ergogenic strategy during high-intensity exercise. METHODS: Eight healthy males ingested either BAl (4.8 g day(-1) for 4 weeks, increased to 6.4 g day(-1) for 2 weeks) or placebo (Pl) (CaCO3) for 6 weeks, in a crossover design (6-week washout between supplements). After each chronic supplementation period participants performed two trials, each consisting of two intense exercise tests performed over consecutive days. Trials were separated by 1 week and consisted of a repeated sprint ability (RSA) test and cycling capacity test at 110 % Wmax (CCT110 %). Placebo (Pl) or SB (300 mg kgbw(-1)) was ingested prior to exercise in a crossover design to creating four supplement conditions (BAl-Pl, BAl-SB, Pl-Pl, Pl-SB). RESULTS: Carnosine increased in the gastrocnemius (n = 5) (p = 0.03) and soleus (n = 5) (p = 0.02) following BAl supplementation, and Pl-SB and BAl-SB ingestion elevated blood HCO3 (-) concentrations (p < 0.01). Although buffering capacity was elevated following both BAl and SB ingestion, performance improvement was only observed with BAl-Pl and BAl-SB increasing time to exhaustion of the CCT110 % test 14 and 16 %, respectively, compared to Pl-Pl (p < 0.01). CONCLUSION: Supplementation of BAl and SB elevated buffering potential by increasing muscle carnosine and blood bicarbonate levels, respectively. BAl ingestion improved performance during the CCT110 %, with no aggregating effect of SB supplementation (p > 0.05). Performance was not different between treatments during the RSA test.


Assuntos
Suplementos Nutricionais , Tolerância ao Exercício/efeitos dos fármacos , Exercício , Bicarbonato de Sódio/farmacologia , beta-Alanina/farmacologia , Adulto , Tampões (Química) , Carnosina/metabolismo , Estudos Cross-Over , Método Duplo-Cego , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Consumo de Oxigênio , Bicarbonato de Sódio/administração & dosagem , Bicarbonato de Sódio/sangue , beta-Alanina/administração & dosagem , beta-Alanina/sangue
20.
Int J Sports Physiol Perform ; 9(4): 627-32, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24155093

RESUMO

PURPOSE: To determine whether gastrointestinal (GI) distress affects the ergogenicity of sodium bicarbonate and whether the degree of alkalemia or other metabolic responses is different between individuals who improve exercise capacity and those who do not. METHODS: Twenty-one men completed 2 cycling-capacity tests at 110% of maximum power output. Participants were supplemented with 0.3 g/kg body mass of either placebo (maltodextrin) or sodium bicarbonate (SB). Blood pH, bicarbonate, base excess, and lactate were determined at baseline, preexercise, immediately postexercise, and 5 min postexercise. RESULTS: SB supplementation did not significantly increase total work done (TWD; P = .16, 46.8 ± 9.1 vs 45.6 ± 8.4 kJ, d = 0.14), although magnitude-based inferences suggested a 63% likelihood of a positive effect. When data were analyzed without 4 participants who experienced GI discomfort, TWD (P = .01) was significantly improved with SB. Immediately postexercise blood lactate was higher in SB for the individuals who improved but not for those who did not. There were also differences in the preexercise-to-postexercise change in blood pH, bicarbonate, and base excess between individuals who improved and those who did not. CONCLUSIONS: SB improved high-intensity-cycling capacity but only with the exclusion of participants experiencing GI discomfort. Differences in blood responses suggest that SB may not be beneficial to all individuals. Magnitude-based inferences suggested that the exercise effects are unlikely to be negative; therefore, individuals should determine whether they respond well to SB supplementation before competition.


Assuntos
Ciclismo , Tolerância ao Exercício/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/administração & dosagem , Bicarbonato de Sódio/administração & dosagem , Equilíbrio Ácido-Base , Adulto , Biomarcadores/sangue , Método Duplo-Cego , Teste de Esforço , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Substâncias para Melhoria do Desempenho/sangue , Bicarbonato de Sódio/sangue , Fatores de Tempo , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA