Acute extracellular fluid volume changes increase ileocolonic resistance to saline flow in anesthetized dogs

We determined the effect of acute extracellular fluid volume changes on saline flow through 4 gut segments (ileocolonic, ileal, ileocolonic sphincter and proximal colon), perfused at constant pressure in anesthetized dogs. Two different experimental protocols were used: hypervolemia (iv saline infusion, 0.9% NaCl, 20 ml/min, volume up to 5% body weight) and controlled hemorrhage (up to a 50% drop in mean arterial pressure). Mean ileocolonic flow (N = 6) was gradually and significantly decreased during the expansion (17.1%, P<0.05) and expanded (44.9%, P<0.05) periods while mean ileal flow (N = 7) was significantly decreased only during the expanded period (38%, P<0.05). Mean colonic flow (N = 7) was decreased during expansion (12%, P<0.05) but returned to control levels during the expanded period. Mean ileocolonic sphincter flow (N = 6) was not significantly modified. Mean ileocolonic flow (N = 10) was also decreased after hemorrhage (retracted period) by 17% (P<0.05), but saline flow was not modified in the other separate circuits (N = 6, 5 and 4 for ileal, ileocolonic sphincter and colonic groups, respectively). The expansion effect was blocked by atropine (0.5 mg/kg, iv) both on the ileocolonic (N = 6) and ileal (N = 5) circuits. Acute extracellular fluid volume retraction and expansion increased the lower gastrointestinal resistances to saline flow. These effects, which could physiologically decrease the liquid volume being supplied to the colon, are possible mechanisms activated to acutely balance liquid volume deficit and excess.

Treatment of hemorrhagic shock with hypertonic saline solution modulates the inflammatory response to live bacteria in lungs

Shock and resuscitation render patients more susceptible to acute lung injury due to an exacerbated immune response to subsequent inflammatory stimuli. To study the role of innate immunity in this situation, we investigated acute lung injury in an experimental model of ischemia-reperfusion (I-R) followed by an early challenge with live bacteria. Conscious rats (N = 8 in each group) were submitted to controlled hemorrhage and resuscitated with isotonic saline (SS, 0.9% NaCl) or hypertonic saline (HS, 7.5% NaCl) solution, followed by intratracheal or intraperitoneal inoculation of Escherichia coli. After infection, toll-like receptor (TLR) 2 and 4 mRNA expression was monitored by RT-PCR in infected tissues. Plasma levels of tumor necrosis factor α and interleukins 6 and 10 were determined by ELISA. All animals showed similar hemodynamic variables, with mean arterial pressure decreasing to nearly 40 mmHg after bleeding. HS or SS used as resuscitation fluid yielded equal hemodynamic results. Intratracheal E. coli inoculation per se induced a marked neutrophil infiltration in septa and inside the alveoli, while intraperitoneal inoculation-associated neutrophils and edema were restricted to the interseptal space. Previous I-R enhanced lung neutrophil infiltration upon bacterial challenge when SS was used as reperfusion fluid, whereas neutrophil influx was unchanged in HS-treated animals. No difference in TLR expression or cytokine secretion was detected between groups receiving HS or SS. We conclude that HS is effective in reducing the early inflammatory response to infection after I-R, and that this phenomenon is achieved by modulation of factors other than expression of innate immunity components.

Estimativa da composição química corporal de tourinhos Santa Gertrudes a partir da composição química e física das 9-10-11ª costelas

Foram obtidas equações de regressão linear simples para estimar a composição química corporal de bovinos Santa Gertrudes, a partir da composição química e física do corte das 9-10-11ª costelas. Quinze tourinhos, entre nove a 15 meses de idade e de 220 a 505 kg de peso, foram mantidos confinados. Os animais foram abatidos após jejum completo de 18 horas, sendo que seis deles foram abatidos após adaptação. A composição química em água, proteína, extrato etéreo e minerais foi determinada no corte das costelas e em amostras obtidas após moagem completa e homogeneização de todos os tecidos corporais, divididos em: sangue, couro, cabeça + patas, vísceras e carcaça. A composição física do corte das costelas foi obtida por separação manual do músculo, gordura e ossos. O peso do corpo vazio foi altamente correlacionado ao peso da carcaça quente (r² = 0,99). As porcentagens de água e extrato etéreo das 9-10-11ª costelas mostraram-se altamente correlacionadas com a composição química do corpo vazio, o que não ocorreu para as porcentagens de proteína e minerais. Esses teores foram calculados pela composição do corpo vazio desengordurado. A composição física do corte das costelas foi eficiente para estimar as porcentagens de água, extrato etéreo e minerais do corpo vazio, utilizando-se a porcentagem de gordura separável das costelas, mas não para estimar o teor de proteína. A composição física do corte das costelas demonstrou ser uma técnica eficiente, mas a composição química apresentou maiores coeficientes de determinação e menores erros da estimativa. Como a porcentagem de água no corpo vazio e no corte das costelas (r² = 0,95), e as porcentagens de água e de extrato etéreo no corpo vazio foram altamente correlacionadas (r² = 0,94), a porcentagem de água no corte das 9-10-11ª costelas poderia ser a única variável para estimativa da composição química corporal.

Efeitos do cetorolaco de trometamina 0,5%, sem conservante, sobre a resposta inflamatória, a sensibilidade e re-epitelização corneal em coelhos submetidos a ulceração química da córnea

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparação do uso do tubo traqueal com balonete preenchido com ar, solução fisiológica ou lidocaína alcalinizada a 1% e a 0,5% em pacientes pediátricos

Pós-graduação em Anestesiologia - FMB

Variations in peak nasal inspiratory flow among healthy students after using saline solutions

Nasal hygiene with saline solutions has been shown to relieve congestion, reduce the thickening of the mucus and keep nasal cavity clean and moist. Evaluating whether saline solutions improve nasal inspiratory flow among healthy children. Students between 8 and 11 years of age underwent 6 procedures with saline solutions at different concentrations. The peak nasal inspiratory flow was measured before and 30min after each procedure. Statistical analysis was performed by means of t test, analysis of variance, and Tukey's test, considering p<0.05. We evaluated 124 children at all stages. There were differences on the way a same concentration was used. There was no difference between 0.9% saline solution and 3% saline solution by using a syringe. The 3% saline solution had higher averages of peak nasal inspiratory flow, but it was not significantly higher than the 0.9% saline solution. It is important to offer various options to patients.

In vitro effects of 3 % hypertonic saline and 20 % mannitol on canine whole blood coagulation and platelet function.

BACKGROUND: Hyperosmolar therapy, using either mannitol or hypertonic saline (HTS), is considered the treatment of choice for intracranial hypertension. However, hyperosmolar agents may impair coagulation and platelet function, limiting their use in patients at risk for hemorrhage. Despite this, studies evaluating the effects of mannitol compared to other hyperosmolar agents in dogs are largely lacking. The aim of this study was to compare the in vitro effects on global hemostasis and platelet function of 20 % mannitol and 3 % HTS on canine blood. METHODS: Citrated whole blood from 15 healthy dogs was diluted with 0.9 % saline, 20 % mannitol and 3 % HTS in ratios of 1:16 and 1:8. Rotational thromboelastometry (ROTEM) was used to assess clotting time (CT), clot formation time (CFT) and maximal clot firmness (MCF) following extrinsic activation (Ex-tem) and after platelet inhibition (Fib-tem). A platelet function analyzer (PFA-100) was used to assess closure time (CtPFA). RESULTS: No significant differences were observed between untreated whole blood and samples diluted with saline. Samples diluted with both mannitol and HTS were hypocoagulable compared to untreated whole blood samples. At a dilution of 1:16, no significant differences were found between any measured parameter in samples diluted with saline compared to mannitol or HTS. At a 1:8 dilution, CtPFA was prolonged in samples diluted with mannitol and HTS compared to saline, and CtPFA was prolonged more with mannitol than HTS. Ex-tem CT was increased at a 1:8 dilution with mannitol compared to HTS. Ex-tem CFT was prolonged at a 1:8 dilution with both agents compared to saline, and was prolonged more with mannitol than HTS. Ex-tem MCF was reduced at a 1:8 dilution with both agents compared to saline. DISCUSSION AND CONCLUSIONS: Data in this study indicate that both mannitol and HTS affect canine platelet function and whole blood coagulation in vitro in a dose-dependent fashion. The most pronounced effects were observed after high dilutions with mannitol, which impaired platelet aggregation, clot formation time, clot strength, and fibrin formation significantly more than HTS. Further in vivo studies are necessary before recommendations can be made

The great fluid debate: saline or so-called "balanced" salt solutions?

BACKGROUND Intravenous fluids are commonly prescribed in childhood. 0.9 % saline is the most-used fluid in pediatrics as resuscitation or maintenance solution. Experimental studies and observations in adults suggest that 0.9 % saline is a poor candidate for fluid resuscitation. Although anesthesiologists, intensive care specialists, perioperative physicians and nephrologists have been the most active in this debate, this issue deserves some physiopathological considerations also among pediatricians. RESULTS As compared with so-called "balanced" salt crystalloids such as lactated Ringer, administration of large volumes of 0.9 % saline has been associated with following deleterious effects: tendency to hyperchloremic metabolic acidosis (called dilution acidosis); acute kidney injury with reduced urine output and salt retention; damaged vascular permeability and stiffness, increase in proinflammatory mediators; detrimental effect on coagulation with tendency to blood loss; detrimental gastrointestinal perfusion and function; possible uneasiness at the bedside resulting in unnecessary administration of more fluids. Nevertheless, there is no firm evidence that these adverse effects are clinically relevant. CONCLUSIONS Intravenous fluid therapy is a medicine like insulin, chemotherapy or antibiotics. Prescribing fluids should fit the child's history and condition, consider the right dose at the right rate as well as the electrolyte levels and other laboratory variables. It is unlikely that a single type of fluid will be suitable for all pediatric patients. "Balanced" salt crystalloids, although more expensive, should be preferred for volume resuscitation, maintenance and perioperatively. Lactated Ringer appears unsuitable for patients at risk for brain edema and for those with overt or latent chloride-deficiency. Finally, in pediatrics there is a need for new fluids to be developed on the basis of a better understanding of the physiology and to be tested in well-designed trials.

A randomized trial of nebulized 3% hypertonic saline with salbutamol in the treatment of acute bronchiolitis in hospitalized infants

OBJECTIVE: Acute bronchiolitis is a common disorder of infants that often results in hospitalization. Apart from supportive care, no therapy has been shown to influence the course of the disease, except for a possible effect of nebulized hypertonic saline (HS). To determine whether this does have beneficial effects on length of stay in hospital or on severity scores, we undertook a double-blind, randomized, controlled trial in a pediatric department of a Portuguese hospital. METHODS: Previously healthy infants, younger than 12 months, hospitalized with mild-to-moderate acute viral bronchiolitis were randomized to receive either nebulized 3% (hypertonic, HS) or 0.9% (normal, NS) saline during their entire hospital stay. Primary endpoints were: length of hospital stay and severity scores on each day of hospitalization. Need for supplemental oxygen, further add-on medications and adverse effects were also analyzed. RESULTS: Sixty-eight patients completed the study (HS: 33; NS: 35). The median length of hospital stay did not differ between groups: HS: 5.6 ± 2.3 days; NS: 5.4 ± 2.1 days (P = 0.747). We found no difference between groups in severity scores from day 1 to day 4. There were no differences in need for supplemental oxygen or add-on medications. Patients in HS group had significantly more cough (46% vs. 20%, P = 0.025) and rhinorrhoe (58% vs. 31%, P = 0.30). CONCLUSION: This study does not support the use of nebulized HS over NS in therapy of hospitalized children with mild-to-moderate acute viral bronchiolitis

Sodium bicarbonate versus isotonic saline solution to prevent contrast-induced nephropathy: a systematic review and meta-analysis

Introduction: Contrast-induced nephropathy is one of the main causes of acute kidney injury and increased hospital-acquired morbidity and mortality. The use of sodium bicarbonate for nephroprotection has emerged as a preventative strategy; however, its efficacy is controversial compared to other strategies, such as hydration using 0.9% saline solution. Objective: To compare the effectiveness of sodium bicarbonate vs. hydration using 0.9% saline solution to prevent contrast-induced acute kidney injury. Methods: A systematic review of studies registered in the COCHRANE, PUBMED, MEDLINE, LILACS, SCIELO and EMBASE databases was conducted. Randomized controlled studies that evaluated the use of 0.9% saline solution vs. sodium bicarbonate to prevent contrast-induced nephropathy were included. Results: A total of 22 studies (5,686 patients) were included. Sodium bicarbonate did not decrease the risk of contrast-induced nephropathy (RD= 0.00; 95% CI= -0.02 to 0.03; p= 0.83; I2= 0%). No significant differences were found in the demand for renal replacement therapy (RD= 0.00; 95% CI= -0.01 to 0-01; I2= 0%; p= 0.99) or in mortality (RD= -0.00; 95% CI= -0.001 to 0.001; I2= 0%; p= 0.51). Conclusions: Sodium bicarbonate administration is not superior to the use of 0.9% saline solution for preventing contrast-induced nephropathy in patients with risk factors, nor is it better at reducing mortality or the need for renal replacement therapy.

Accuracy of three electronic apex locators in the presence of different irrigating solutions

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic® and the Root ZX® EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.

Effect of triiodothyronine on the maxilla and masseter muscles of the rat stomatognathic system

The maxilla and masseter muscles are components of the stomatognathic system involved in chewing, which is frequently affected by physical forces such as gravity, and by dental, orthodontic and orthopedic procedures. Thyroid hormones (TH) are known to regulate the expression of genes that control bone mass and the oxidative properties of muscles; however, little is known about the effects of TH on the stomatognathic system. This study investigated this issue by evaluating: i) osteoprotegerin (OPG) and osteopontine (OPN) mRNA expression in the maxilla and ii) myoglobin (Mb) mRNA and protein expression, as well as fiber composition of the masseter. Male Wistar rats (~250 g) were divided into thyroidectomized (Tx) and sham-operated (SO) groups (N = 24/group) treated with T3 or saline (0.9%) for 15 days. Thyroidectomy increased OPG (~40%) and OPN (~75%) mRNA expression, while T3 treatment reduced OPG (~40%) and OPN (~75%) in Tx, and both (~50%) in SO rats. Masseter Mb mRNA expression and fiber type composition remained unchanged, despite the induction of hypo- and hyperthyroidism. However, Mb content was decreased in Tx rats even after T3 treatment. Since OPG and OPN are key proteins involved in the osteoclastogenesis inhibition and bone mineralization, respectively, and that Mb functions as a muscle store of O2 allowing muscles to be more resistant to fatigue, the present data indicate that TH also interfere with maxilla remodeling and the oxidative properties of the masseter, influencing the function of the stomatognathic system, which may require attention during dental, orthodontic and orthopedic procedures in patients with thyroid diseases.

Estudo eletroquímico comparativo do aço ISO 5832-9 em diferentes meios de interesse biológico

Foi estudado o comportamento eletroquímico a 37°C do aço inoxidável ISO 5832-9, em meios de NaCl 0,9 %, de Ringer Lactato e meio mínimo de Eagle (MEM), por voltametria linear e análises da superfície por microscopia eletrônica de varredura (MEV) e por espectroscopia por dispersão de energia (EDS). Foram feitos ensaios mecânicos e testes de toxicidade. O aço ISO 5832-9 se encontra passivado no potencial de corrosão e não apresenta corrosão por pite nos três meios estudados em toda faixa de potencial investigada, desde o potencial de corrosão até 50 mV acima do potencial de transpassivação. Em meio de MEM, no entanto, as análises por MEV e EDS mostraram que o referido aço, nesse valor mais elevado de potencial, apresentou um comportamento diferente, com perda das inclusões de óxido de manganês. Os potenciais de corrosão, Ecorr (potencial de circuito aberto estacionário) bem como os valores de densidade de corrente de passivação, variaram na seguinte ordem: Ecorr, RL < Ecorr, NaCl < Ecorr, MEM. e jMEM << jRL ≅ jNaCl. No ensaio de citotoxicidade, o aço foi caracterizado como não-tóxico.