[Intravenous sodium bicarbonate. When, how and why to use it?] / Bicarbonato de sodio intravenoso ¿Cuándo, cómo y por qué utilizarlo?

Severe metabolic acidosis is defined by a pH < 7.2 with HCO3- < 8 mE- q/L in plasma. Its best treatment is to correct the underlying cause. However, acidemia produces multiple complications such as resistance to the action of catecholamines, pulmonary vasoconstriction, impaired cardiovascular function, hyperkalemia, immunological dysregulation, respiratory muscle fatigue, neurological impairment, cellular dysfunction, and finally, it contributes to multisystemic failure. Intravenous NaHCO3 buffers severe acidemia, preventing the associated damage and gains time while the causal disease is corrected. Its indication requires a risk-benefit assessment, considering its complications. These are hypernatremia, hypokalemia, ionic hypocalcemia, rebound alkalosis, and intracellular acidosis. For this reason, therapy must be "adapted" and administered judiciously. The patient will require monitoring with serial evaluation of the internal environment, especially arterial blood gases, plasma electrolytes, and ionized calcium. Isotonic solutions should be preferred instead of hypertonic bicarbonate. The development of hypernatremia must be prevented, calcium must be provided for hypocalcemia to improve cardiovascular function. Furthermore, in mechanically ventilated patients, a respiratory response similar to the one that would develop physiologically, must be established to be able to extract excess CO2 and thus avoid intracellular acidosis. It is possible to estimate the bicarbonate deficit, speed, and volume of its infusion. However, the calculations are only for reference. More important is to start intravenous NaHCO3 when needed, administer it judiciously, manage its side effects, and continue it to a safe goal. In this review we address all the necessary elements to consider in the administration of intravenous NaHCO3, highlighting why it is the best buffer for the management of severe metabolic acidosis.

The efficacy and safety of citrate mixture vs sodium bicarbonate on urine alkalization in Chinese primary gout patients with benzbromarone: a prospective, randomized controlled study.

OBJECTIVES: To compare the efficacy and safety of citrate mixture and sodium bicarbonate on urine alkalization in gout patients under benzbromarone treatment. METHODS: A prospective, randomized, parallel controlled trial was conducted among 200 gout patients in the dedicated gout clinic of the Affiliated Hospital of Qingdao University. The participants were randomly divided into two groups (1:1), sodium bicarbonate group (3 g/day) and citrate mixture group (7 g/day). All patients were prescribed with 25 mg/day benzbromarone at initiation and maintained at a dose of 50 mg/day. Clinical and biochemical data were collected at each follow-up time point (baseline, weeks 2, 4, 8 and 12). RESULTS: A total of 182 patients completed the 12-week urine alkalization study. The urine pH value of both groups increased significantly from the baseline to the final follow-up time point (sodium bicarbonate group, 5.50-6.00, P < 0.05; citrate mixture group, 5.53-5.93, P < 0.05). While the comparisons regarding urine pH between treatment groups showed no significant differences for each time point. The estimated glomerular filtration rate (eGFR) dropped significantly after 12 weeks' trial in the sodium bicarbonate group (P < 0.01), while it was comparable between baseline and the last follow-up (P > 0.05) in the citrate mixture group. Results of urine analysis showed that the incident rate of occult blood in the sodium bicarbonate group was higher than that in the citrate mixture group (38 vs 24%, P < 0.05), accompanied by a similar occurrence of kidney stones. After 12-week follow-up, the frequency of twice gout flare in the citrate mixture group was significantly lower than that in sodium bicarbonate group (4 vs 12%, P = 0.037). No treatment-emergent adverse events occurred. CONCLUSION: The efficacy of citrate mixture on urine alkalization is comparable to sodium bicarbonate under benzbromarone treatment without significant adverse events. Citrate mixture is superior to sodium bicarbonate in lowering the incidence of urine occult blood and the frequency of gout attacks. TRIAL REGISTRATION: Registered with ChiCTR (http://www.chictr.org.cn), No. ChiCTR1800018518.

Effect of Del Nido cardioplegia on ventricular arrhythmias after cardiovascular surgery.

BACKGROUND: Del Nido cardioplegia (DNC) has been proven safe and effective in pediatric patients. However, the use of DNC in adult undergoing cardiovascular surgery lacks support with substantial evidence. This study aimed to evaluate the efficacy of DNC as a cardioplegia of prophylaxis to ventricular arrhythmias associated to cardiovascular surgery in adult patients. METHODS: This study recruited nine hundred fifty-four patients who underwent cardiopulmonary bypass surgeries in Nanjing Hospital affiliated to Nanjing Medical University between January 2019 and December 2019. Among 954 patients, 324 patients were treated with DNC (DNC group), and 630 patients were treated with St. Thomas cardioplegia (STH group). The incidence of postoperative arrhythmia as well as other cardiovascular events relavant to the surgery were investigated in both groups. RESULTS: In DNC group, the incidence of postoperative ventricular arrhythmias was lower (12.4% vs. 17.4%, P = 0.040), and the length of ICU stay was shorter (1.97 ± 1.49 vs. 2.26 ± 1.46, P = 0.004). Multivariate logistic regression demonstrated that the use of DNC helped to reduce the incidence of postoperative ventricular arrhythmias (adjusted odds ratio 0.475, 95% CI 0.266-0.825, P = 0.010). The propensity score-based analysis and subgroup analysis indicated that DNC has the same protecting effects towards myocardial in all kinds of cardiopulmonary bypass surgeries. CONCLUSIONS: Del Nido cardioplegia may potentially reduce the incidence of postoperative ventricular arrhythmias, shorten the length of ICU stay and improve the overall outcome of the patients undergoing cardiovascular surgery.

Del Nido versus HTK cardioplegia for myocardial protection during adult complex valve surgery: a retrospective study.

BACKGROUND: Histidine-tryptophan-ketoglutarate (HTK) and del Nido (DN) cardioplegia are intracellular-type and extracellular-type solution respectively, both can provide a long period of myocardial protection with single-dose infusion, but studies comparing the two are rare for adult cardiac surgery. This study aims to evaluate whether DN is suitable for cardioplegia in complex and high-risk valve surgery with long-term cardiac ischemia when compared with HTK. METHODS: The perioperative records of adult patients infused with DN/HTK as a cardioplegic solution who underwent complex valve surgery with an expected myocardial ischaemic duration longer than 90 min between Oct 2018 and Oct 2019 were analysed retrospectively. RESULTS: Of the 160 patients who received DN/HTK and underwent complex valve surgery, we propensity matched 73 pairs. Both groups achieved satisfactory cardiac arrest effects, and no significant difference was found in their cTnI and CK-MB levels within 12 to 72 h postoperatively. The DN group had a higher rate of return to spontaneous rhythm (0.88 v 0.52, P < 0.001), a lower frequency of postoperative severe arrythmias (12% v 26%, P = 0.036), a higher postoperative stroke volume (65 v 59 ml, P = 0.011) and a higher cardiac output (6.0 v 4.9 L/min, P = 0.007) as evaluated by echocardiography, fewer transfusions and shorter ICU stays (both P < 0.05). The two groups had similar inotrope usage and similar incidences of low cardiac output, morbidities and mortality. Subgroup analysis showed that when the aortic clamping time was greater than 120 min, the advantages of DN were weakened. CONCLUSIONS: DN can be safely applied to complex valve surgery, and it has a similar myocardial protection effect as HTK. Further prospective studies are required to verify these retrospective findings. Trial registration retrospectively registered.

Comparison of Chloroprocaine Versus Lidocaine With Epinephrine, Sodium Bicarbonate, and Fentanyl for Epidural Extension Anesthesia in Elective Cesarean Delivery: A Randomized, Triple-Blind, Noninferiority Study.

BACKGROUND: For emergent intrapartum cesarean delivery (CD), the literature does not support the use of any particular local anesthetic solution to extend epidural analgesia to cesarean anesthesia. We hypothesized that 3% chloroprocaine (CP) would be noninferior to a mixture of 2% lidocaine, 150 µg of epinephrine, 2 mL of 8.4% bicarbonate, and 100 µg of fentanyl (LEBF) in terms of onset time to surgical anesthesia. METHODS: In this single-center randomized noninferiority trial, adult healthy women undergoing CD were randomly assigned to epidural anesthesia with either CP or LEBF. Sensory blockade (pinprick) to T10 was established before operating room (OR) entry for elective CD. On arrival to the OR, participants received the epidural study medications in a standardized manner to simulate the conversion of "epidural labor analgesia to surgical anesthesia." The primary outcome was the time to loss of touch sensation at the T7 level. A noninferiority margin was set at 3 minutes. The secondary outcome was the need for intraoperative analgesia supplementation. RESULTS: In total, 70 women were enrolled in the study. The mean onset time to achieve a bilateral sensory block to touch at the T7 dermatome level was 655 (standard deviation [SD] = 258) seconds for group CP and 558 (269) seconds for group LEBF, a difference in means of 97 seconds (90% confidence interval [CI], SD = -10.6 to 204; P = .10 for noninferiority). The upper limit of the 90% CI for the mean difference exceeded the prespecified 3-minute noninferiority margin. There was no meaningful difference in the requirement for intraoperative analgesia between the 2 groups. CONCLUSION: Both anesthetic solutions have a rapid onset of anesthesia when used to extend low-dose epidural sensory block to surgical anesthesia. Data from the current study provide insufficient evidence to confirm that CP is noninferior to LEBF for rapid epidural extension anesthesia for CD, and further research is required to determine noninferiority.

Relationship between mortality and use of sodium bicarbonate at the time of dialysis initiation: a prospective observational study.

BACKGROUND: Patients with chronic kidney disease often experience metabolic acidosis. Whether oral sodium bicarbonate can reduce mortality in patients with metabolic acidosis has been debated for years. Hence, this study was conducted to evaluate the utility of sodium bicarbonate in patients who will undergo dialysis therapy. In this study, we investigated the effect of oral sodium bicarbonate therapy on mortality in patients with end-stage kidney disease (ESKD) initiated on dialysis therapy. METHODS: We conducted an observational study of patients when they started dialysis therapy. There were 17 centres participating in the Aichi Cohort Study of Prognosis in Patients Newly Initiated into Dialysis. Data were available on patients' sex, age, use of sodium bicarbonate, drug history, medical history, vital data, and laboratory data. We investigated whether patients on oral sodium bicarbonate for more than three months before dialysis initiation had a better prognosis than those without sodium bicarbonate therapy. The primary outcome was defined as all-cause mortality. RESULTS: The study included 1524 patients with chronic kidney disease who initiated dialysis between October 2011 and September 2013. Among them, 1030 were men and 492 women, with a mean age of 67.5 ± 13.1 years. Of these, 677 used sodium bicarbonate and 845 did not; 13.6% of the patients in the former group and 21.2% of those in the latter group died by March 2015 (p <  0.001). Even after adjusting for various factors, the use of sodium bicarbonate independently reduced mortality (p <  0.001). CONCLUSIONS: The use of oral sodium bicarbonate at the time of dialysis initiation significantly reduced all-cause mortality in patients undergoing dialysis therapy.

Oral sodium bicarbonate protocol for high-dose methotrexate urine alkalinization: A pediatric experience.

INTRODUCTION: Methotrexate (MTX) is a cytotoxic antimetabolite. Intravenous (IV) hydration and urine alkalinization with sodium bicarbonate (NaHCO3) can mitigate nephrotoxicity associated with high-dose MTX (HDMTX, doses ≥500 mg/m2). A shortage of IV NaHCO3 in 2017 prompted Alberta Children's Hospital (ACH) and Stollery Children's Hospital (SCH) to adopt an alternative protocol including oral NaHCO3 and IV hydration with Lactated Ringer's (LR). METHODS: A retrospective chart review was conducted for ACH and SCH inpatients who received HDMTX between January and December 2017. The primary outcome was the proportion of cycles with delayed HDMTX clearance within the IV and oral cohorts. Secondary outcomes include NaHCO3 administered until clearance, NaHCO3 required to reach pH ≥7, time to reach pH ≥7, incidence of pH <7, time to clearance, and time to discharge. Adverse effects associated with delayed clearance or NaHCO3 administration were also reported. RESULTS: 112 MTX cycles were included, 50 and 62 from the IV and oral cohorts, respectively. Clearance delays beyond protocol expectations occurred in 10 cycles (8.9%), 5 from each cohort (p = 0.72). Differences between cohorts were not statistically significant, except the amounts of NaHCO3 required until clearance (383 vs. 277 mmol/m2, p = 0.005) and to reach pH ≥7 (52 vs. 40 mmol/m2, p = 0.004) were lower in the oral cohort. Incidences of adverse effects were not different. CONCLUSIONS: Oral NaHCO3 with LR is a feasible alternative for urine alkalinization. The total dose of NaHCO3 utilized was lower in the oral cohort, with no additional delays in clearance.

A Randomized Trial Comparing the Safety, Adherence, and Pharmacodynamics Profiles of Two Doses of Sodium Bicarbonate in CKD: the BASE Pilot Trial.

BACKGROUND: Oral sodium bicarbonate (NaHCO3) may preserve kidney function in CKD, even if initiated when serum bicarbonate concentration is normal. Adequately powered trials testing this hypothesis have not been conducted, partly because the best dose for testing is unknown. METHODS: This multicenter pilot trial assessed the safety, tolerability, adherence, and pharmacodynamics of two doses of NaHCO3 over 28 weeks in adults with eGFR 20-44 or 45-59 ml/min per 1.73 m2 with urinary albumin/creatinine (ACR) ≥50 mg/g and serum bicarbonate 20-28 meq/L. We randomly assigned 194 participants from ten clinical sites to receive higher-dose (HD-NaHCO3; 0.8 meq/kg of lean body wt per day; n=90) or lower-dose (LD-NaHCO3; 0.5 meq/kg of lean body wt per day; n=52) NaHCO3 or matching placebo (n=52). The dose was adjusted depending on side effects. The prescribed dose at week 28 was the primary outcome; a dose was considered acceptable for a full-scale trial if ≥67% of participants were on full-dose and ≥80% were on ≥25% of the per-protocol dose. RESULTS: Mean±SD baseline eGFR was 36±9 ml/min per 1.73 m2, serum bicarbonate was 24±2 meq/L, and median (IQR) ACR was 181 (25-745) mg/g. Both doses were well tolerated without significant changes in BP, weight, or serum potassium. The proportions of adverse events and hospitalizations were similar across the groups. Consequently, 87% in HD-NaHCO3, 96% in LD-NaHCO3, and 87% in placebo were on full dose at week 28; and 91% in HD-NaHCO3, 98% in LD-NaHCO3, and 92% in placebo were on ≥25% of the per-protocol dose. Mean urinary ammonium excretion was 25% lower and serum bicarbonate concentration was 1.3 meq/L higher in HD-NaHCO3 compared with LD-NaHCO3 at week 28. However, mean ACR increased by 12% in the lower-dose group and 30% in the higher-dose group. CONCLUSIONS: Both NaHCO3 doses were well tolerated over 28 weeks with no significant difference in adverse events or hospitalization compared with placebo. The higher dose lowered urinary ammonium excretion and increased serum bicarbonate more than the lower dose but was associated with a greater increase in ACR. The higher 0.8 meq/kg of lean body wt per day dose of NaHCO3 may be a reasonable choice for future trials.

Alkali supplementation as a therapeutic in chronic kidney disease: what mediates protection?

Sodium bicarbonate (NaHCO3) has been recognized as a possible therapy to target chronic kidney disease (CKD) progression. Several small clinical trials have demonstrated that supplementation with NaHCO3 or other alkalizing agents slows renal functional decline in patients with CKD. While the benefits of NaHCO3 treatment have been thought to result from restoring pH homeostasis, a number of studies have now indicated that NaHCO3 or other alkalis may provide benefit regardless of the presence of metabolic acidosis. These data have raised questions as to how NaHCO3 protects the kidneys. To date, the physiological mechanism(s) that mediates the reported protective effect of NaHCO3 in CKD remain unclear. In this review, we first examine the evidence from clinical trials in support of a beneficial effect of NaHCO3 and other alkali in slowing kidney disease progression and their relationship to acid-base status. Then, we discuss the physiological pathways that have been proposed to underlie these renoprotective effects and highlight strengths and weaknesses in the data supporting each pathway. Finally, we discuss how answering key questions regarding the physiological mechanism(s) mediating the beneficial actions of NaHCO3 therapy in CKD is likely to be important in the design of future clinical trials. We conclude that basic research in animal models is likely to be critical in identifying the physiological mechanisms underlying the benefits of NaHCO3 treatment in CKD. Gaining an understanding of these pathways may lead to the improved implementation of NaHCO3 as a therapy in CKD and perhaps other disease states.

Transitioning to Del Nido cardioplegia for all-comers: the next switching gear?

BACKGROUND: Exclusive use of Del Nido cardioplegia administration in all adult patients undergoing cardiac surgery has been studied for operative, postoperative and myocardial protection outcomes. METHODS: From November 2016 to October 2017, Del Nido cardioplegia was used in 131 consecutive patients (DN group). Using a propensity score, DN group was compared to 251 patients having received intermittent cold blood cardioplegia (CB group). RESULTS: Preoperative characteristics were similar in DN and CB groups. Operative outcomes were statistically different (p < 0.0001): cardiopulmonary bypass (CPB) time (DN 105.9 ± 46.5, CB 131.2 ± 38.8); aortic cross-clamp time (DN 80.8 ± 35.5, CB 102.2 ± 31.3); operative time (DN 203.1 ± 65.0, CB 241.5 ± 54.7); total cardioplegia volume (DN 1328 ± 879, CB 3773 ± 1226); and peak glycemia on CPB (DN 8.2 ± 2.3, CB 9.0 ± 1.8). No statistical differences were noted in intensive care unit stay, hospital stay and hospital death. Myocardial protection outcomes were similar: discharge left ventricular ejection fraction (DN 52 ± 11, CB 51 ± 10); Troponin levels at the end of the surgery (DN 871 ± 1623, CB 1958 ± 854), day 1 (DN 853 ± 1139, CB 993 ± 8234) and day 4 (DN 442 ± 540, CB 463 ± 317). CONCLUSION: Del Nido cardioplegia use in all adult cardiac surgeries is associated with improved surgical efficiency. The design of larger trials including adults combined cardiac procedures and emergencies is needed.

An unusual cause of metabolic alkalosis: hiding in plain sight.

BACKGROUND: Sodium bicarbonate, in the form of baking soda, is widely used as a home remedy, and as an additive for personal and household cleaning products. Its toxicity has previously been reported following oral ingestion in the setting of dyspepsia. However, its use as a non-ingested agent, like a toothpaste additive, has not been reported as a potential cause of toxicity. CASE PRESENTATION: We are reporting a case of an 80-year-old woman who presented with chronic metabolic alkalosis and hypokalemia secondary to exogenous alkali exposure from baking soda as a toothpaste additive, which might have represented an underreported ingestion of the substance. CONCLUSIONS: Considering that one teaspoon of baking soda provides approximately 59 m-equivalents (mEq) of bicarbonate, specific questioning on its general use should be pursued in similar cases of chloride resistant metabolic alkalosis.

Enteric-Coated Sodium Bicarbonate Attenuates Gastrointestinal Side-Effects.

Enteric-formulated capsules can mitigate gastrointestinal (GI) side effects following sodium bicarbonate (NaHCO3) ingestion; however, it remains unclear how encapsulation alters postingestion symptoms and acid-base balance. The current study aimed to identify the optimal ingestion form to mitigate GI distress following NaHCO3 ingestion. Trained males (n = 14) ingested 300 mg/kg body mass of NaHCO3 in gelatin (GEL), delayed-release (DEL), and enteric-coated (ENT) capsules or a placebo in a randomized cross-over design. Blood bicarbonate anion concentration, potential hydrogen, and GI symptoms were measured pre- and postingestion for 3 hr. Fewer GI symptoms were reported with ENT NaHCO3 than with GEL (p = .012), but not with DEL (p = .106) in the postingestion phase. Symptom severity decreased with DEL (4.6 ± 2.8 arbitrary units) compared with GEL (7.0 ± 2.6 arbitrary units; p = .001) and was lower with ENT (2.8 ± 1.9 arbitrary units) compared with both GEL (p < .0005) and DEL (p = .044) NaHCO3. Blood bicarbonate anion concentration increased in all NaHCO3 conditions compared with the placebo (p < .0005), although this was lower with ENT than with GEL (p = .001) and DEL (p < .0005) NaHCO3. Changes in blood potential hydrogen were reduced with ENT compared with GEL (p = .047) and DEL (p = .047) NaHCO3, with no other differences between the conditions. Ingestion of ENT NaHCO3 attenuates GI disturbances for up to 3 hr postingestion. Therefore, ENT ingestion forms may be favorable for those who report GI disturbances with NaHCO3 supplementation or for those who have previously been deterred from its use altogether.

Adverse events associated with currently used medical treatments for cystinuria and treatment goals: results from a series of 442 patients in France.

OBJECTIVE: To evaluate medical treatments, in terms of adverse events (AEs) and therapeutic goals, in a large series of patients with cystinuria. PATIENTS AND METHODS: Data from 442 patients with cystinuria were recorded retrospectively. Crystalluria was studied in 89 patients. A mixed-effects logistic regression model was used to estimate how urine pH, specific gravity and cysteine-binding thiols (CBT) correlate with risk of cystine crystalluria. RESULTS: Alkalizing agents and CBT agents were given to 88.8% (n = 381) and 55.3% (n = 238) of patients, respectively. Gastrointestinal AEs were reported in 12.3%, 10.4% and 2.6% of patients treated with potassium bicarbonate, potassium citrate and sodium bicarbonate, respectively (P = 0.008). The percentages of patients who experienced at least one AE with tiopronin (24.6%) and with D-penicillamine (29.5%) were similar (P = 0.45). Increasing urine pH and decreasing urine specific gravity significantly reduced the risk of cystine crystalluria, whereas D-penicillamine and tiopronin treatments did not reduce this risk (odds ratio [OR] 1 for pH ≤6.5; OR 0.52 [95% confidence interval {95% CI} 0.28-0.95] for 7.0 8.0, P <0.001). CONCLUSION: Adverse events were frequent with D-penicillamine and tiopronin. Alkaline hyperdiuresis was well tolerated and reduced cystine crystalluria. Urine specific gravity ≤1.005 and urine pH >7.5, while warning about calcium-phosphate crystallization, should be the goals of medical therapy.

Effect of Stacked Sodium Bicarbonate Loading on Repeated All-out Exercise.

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.

The effects of sodium bicarbonate ingestion on cycling performance and acid base balance recovery in acute normobaric hypoxia.

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.

Kidney Injury from Recurrent Heat Stress and Rhabdomyolysis: Protective Role of Allopurinol and Sodium Bicarbonate.

BACKGROUND: Heat stress and rhabdomyolysis are major risk factors for the occurrence of repeated acute kidney injury in workers exposed to heat and strenuous work. These episodes, in turn, may progress to chronic kidney disease. OBJECTIVE: The purpose of this study was to test the effect of allopurinol (AP) and sodium bicarbonate on the kidney injury induced by recurrent heat stress dehydration with concomitant repeated episodes of rhabdomyolysis. METHODS: The model consisted of heat stress exposure (1 h, 37°C) plus rhabdomyolysis (R) induced by repetitive IM injections of glycerol (7.5 mL/kg BW days) in the rat. In addition, to replicate the human situation, uricase was inhibited (oxonic acid [OA] 750 mg/K/d) to increase uric acid (UA) levels. Additional groups were treated either with AP 150 mg/L, n = 10, bicarbonate (BC; 160 mM, n = 10), or both (AP + BC, n = 10) in drinking water. We also included 2 control groups consisting of normal controls (N-Ref, n = 5) and uricase-inhibited rats (OA, n = 5) that were not exposed to heat or muscle injury. Groups were studied for 35 days. RESULTS: Uricase-inhibited rats exposed to heat and rhabdomyolysis developed pathway and increased intrarenal oxidative stress and inflammasome activation. Kidney injury could be largely prevented by AP, and also BC, although the treatments were not synergistic. CONCLUSION: Increased levels of UA may play an important role in the renal alterations induced by heat stress and continuous episodes of rhabdomyolysis. Therefore, treatments aimed to reduce hyperuricemia may help to decrease the renal burden in these conditions. Clinical trials are suggested to test whether this is also true in humans.

Determinants of curvature constant (W') of the power duration relationship under normoxia and hypoxia: the effect of pre-exercise alkalosis.

PURPOSE: This study investigated the effect of induced alkalosis on the curvature constant (W') of the power-duration relationship under normoxic and hypoxic conditions. METHODS: Eleven trained cyclists (mean ± SD) Age: 32 ± 7.2 years; body mass (bm): 77.0 ± 9.2 kg; VO2peak: 59.2 ± 6.8 ml·kg-1·min-1 completed seven laboratory visits which involved the determination of individual time to peak alkalosis following sodium bicarbonate (NaHCO3) ingestion, an environment specific ramp test (e.g. normoxia and hypoxia) and four x 3 min critical power (CP) tests under different experimental conditions. Participants completed four trials: alkalosis normoxia (ALN); placebo normoxia (PLN); alkalosis hypoxia (ALH); and placebo hypoxia (PLH). Pre-exercise administration of 0.3 g.kg-1 BM of NaHCO3 was used to induce alkalosis. Environmental conditions were set at either normobaric hypoxia (FiO2: 14.5%) or normoxia (FiO2: 20.93%). RESULTS: An increase in W' was observed with pre-exercise alkalosis under both normoxic (PLN: 15.1 ± 6.2 kJ vs. ALN: 17.4 ± 5.1 kJ; P = 0.006) and hypoxic conditions (ALN: 15.2 ± 4.9 kJ vs. ALN: 17.9 ± 5.2 kJ; P < 0.001). Pre-exercise alkalosis resulted in a larger reduction in bicarbonate ion (HCO3-) concentrations during exercise in both environmental conditions (p < 0.001) and a greater blood lactate accumulation under hypoxia (P = 0.012). CONCLUSION: Pre-exercise alkalosis substantially increased W' and, therefore, may determine tolerance to exercise above CP under normoxic and hypoxic conditions. This may be due to NaHCO3 increasing HCO3- buffering capacity to delay exercise-induced acidosis, which may, therefore, enhance anaerobic energy contribution.

Comparison of enteral and parenteral methods of urine alkalinization in patients receiving high-dose methotrexate.

Purpose Hyperhydration and urinary alkalinization is implemented with all high-dose (HD)-methotrexate infusions to promote excretion and prevent precipitation of methotrexate in the renal tubules. Our institution utilized enteral alkalinizing agents (sodium bicarbonate tablets and sodium citrate/citric acid solution) to alkalinize the urine of patients receiving HD-methotrexate during a parenteral sodium bicarbonate and sodium acetate shortage. The purpose of this study is to establish the safety and efficacy of the enteral route for urine alkalinization. Methods A single-center, retrospective, cohort study was conducted comparing cycles of HD-methotrexate using enteral alkalinizing agents to parenteral sodium bicarbonate. The primary objective was to compare the time, in hours, from administration of first inpatient administered dose of alkalinizing agent to time of achieving goal urine pH. Secondary objectives evaluated total dose of sodium bicarbonate required to achieve goal urine pH, time from start of urine alkalinizing agent until time of achieving methotrexate level safe for discharge, and toxicities associated with methotrexate and the alkalinizing agents. Results A total of 118 patients were included in this study, equally divided into two cohorts based on parenteral versus enteral routes of administration. No statistical difference was determined between the two cohorts regarding time to goal urine pH (6.5 h versus 7.9 h, P = 0.051) or regarding time to methotrexate level deemed safe for discharge (63.5 h versus 62.5 h, p = 0.835). There were no significant differences in methotrexate-induced toxicities. Conclusion Our study found enteral routes of urine alkalinization to be a viable alternative to the traditional parenteral sodium bicarbonate, especially during parenteral sodium bicarbonate and acetate shortages.

A combination of additives can synergically decrease acrylamide content in gingerbread without compromising sensory quality.

BACKGROUND: The present study tested whether replacement of the leavening agent ammonium carbonate by sodium hydrogen carbonate in combination with calcium cation and acidifying agent will synergically decrease acrylamide (AA) content in gingerbread. RESULTS: The type of leavening agent and the presence of Ca2+ and citric acid accounted for 33.6%, 13.2% and 53.2% of the explained variability of the AA content, respectively (P < 0.01). The AA content in gingerbread produced with (NH4 )2 CO3 alone was 186.5 µg kg-1 . Irrespective of other tested additives, NaHCO3 decreased (P < 0.05) AA content to 42% compared to (NH4 )2 CO3 . Combination of NaHCO3 + CaCl2 + citric acid in dough reduced (P < 0.05) AA content below the limit of detection (25 µg kg-1 ). The AA content in gingerbread (y; µg kg-1 ) decreased with an increasing number of additives used (x) according to the equation y = 158.8 - 47.94x (r2 = 0.42; P < 0.0001). A comprehensive sensory analysis did not indicate any significant deterioration (P > 0.05) in the organoleptic quality of gingerbread produced using calcium cation and citric acid. CONCLUSION: The present study demonstrates that the combination of additives NaHCO3 /Ca2+ /citric acid synergically decreases AA content in gingerbread without compromising the sensory quality. © 2016 Society of Chemical Industry.

Effect of denture cleansing solutions on different retentive attachments.

STATEMENT OF PROBLEM: Various Locator abutments and attachments are available commercially for use in overdenture patients. Patients are advised to use cleansing agents to keep their overdentures clean. The effect of different cleansing agents on attachments with different retention is not known. PURPOSE: The purpose of this in vitro study was to evaluate the retention of 3 Locator abutment attachments after they were soaked in 3 different cleansing solutions. MATERIAL AND METHODS: An implant analog with a diameter of 4.1 mm was embedded into acrylic resin, and 1 Locator abutment was placed onto the analog. Seven specimens of clear, pink, and blue Locator attachments (n=7) were soaked in 3 different denture-cleansing solutions (NaOCl, sodium perborate, sodium perborate-sodium bicarbonate) for a time simulating 6 months of clinical use. The control group was soaked in tap water. A testing machine was used to test the attachments' retention. The retention of the attachments after they were soaked in denture cleansers was compared among the groups with repeated-measures analysis of variance followed by the Tukey HSD test (α=.05). RESULTS: The retention of the clear attachments was significantly less after they had been soaked in sodium bicarbonate-containing denture cleanser (P=.001). The retention of the pink Locator attachments was no different after they had been soaked in the different solutions, and the retention of the blue Locator attachments decreased significantly after they had been soaked in the NaOCl and sodium bicarbonate cleansing agents (P=.002). CONCLUSIONS: Attachments of different colors and retention were affected differently by cleansing agents.