Effect of hypertonic saline treatment on the inflammatory response after hydrochloric acid-induced lung injury in pigs

OBJECTIVES: Hypertonic saline has been proposed to modulate the inflammatory cascade in certain experimental conditions, including pulmonary inflammation caused by inhaled gastric contents. The present study aimed to assess the potential anti-inflammatory effects of administering a single intravenous dose of 7.5% hypertonic saline in an experimental model of acute lung injury induced by hydrochloric acid. METHODS: Thirty-two pigs were anesthetized and randomly allocated into the following four groups: Sham, which received anesthesia and were observed; HS, which received intravenous 7.5% hypertonic saline solution (4 ml/kg); acute lung injury, which were subjected to acute lung injury with intratracheal hydrochloric acid; and acute lung injury + hypertonic saline, which were subjected to acute lung injury with hydrochloric acid and treated with hypertonic saline. Hemodynamic and ventilatory parameters were recorded over four hours. Subsequently, bronchoalveolar lavage samples were collected at the end of the observation period to measure cytokine levels using an oxidative burst analysis, and lung tissue was collected for a histological analysis. RESULTS: Hydrochloric acid instillation caused marked changes in respiratory mechanics as well as blood gas and lung parenchyma parameters. Despite the absence of a significant difference between the acute lung injury and acute lung injury + hypertonic saline groups, the acute lung injury animals presented higher neutrophil and tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-8 levels in the bronchoalveolar lavage analysis. The histopathological analysis revealed pulmonary edema, congestion and alveolar collapse in both groups; however, the differences between groups were not significant. Despite the lower cytokine and neutrophil levels observed in the acute lung injury + hypertonic saline group, significant differences were not observed among the treated and non-treated groups. ...

Avaliação da resposta inflamatória pulmonar de suínos submetidos a lesão pulmonar aguda induzida por ácido clorídrico e tratados com solução salina hipertônica / Lung inflammatory response in pigs submitted to acute pulmonary injury by hydrochloric acid and treated with hypertonic saline

INTRODUÇÃO: A lesão pulmonar aguda (LPA) decorrente de aspiração do conteúdo gástrico é freqüente em pacientes com nível de consciência comprometido e depressão dos reflexos de vias aéreas. A solução salina hipertônica (HS) a 7,5% apresenta resultados ainda controversos quanto ao seu potencial efeito protetor na resposta inflamatória pulmonar. OBJETIVOS: Este estudo teve como objetivo avaliar o potencial efeito antiinflamatório da solução salina hipertônica no modelo experimental de lesão pulmonar por aspiração de ácido clorídrico (HCl). MÉTODOS: Foram utilizados 32 suínos (n=32; 8/grupo) divididos aleatoriamente nos seguintes grupos: Sham, onde os animais foram somente anestesiados, ventilados e observados; HS, onde os animais receberam infusão de HS a 7,5% (4 ml/kg), sem LPA; ALI, onde os animais foram submetidos à LPA com HCl; ALI+HS, onde os animais foram submetidos à LPA com HCl e tratados com HS a 7,5% (4 ml/kg). Foram mensurados parâmetros hemodinâmicos e ventilatórios. Amostras de sangue foram coletadas para hemogasometria e análise dos níveis plasmáticos de TNF-?. Foram coletadas amostras do lavado broncoalveolar para mensuração das seguintes citocinas: IL-1, IL-6, IL-8, IL-10 e TNF-?, e realização do burst oxidativo das células pulmonares. O tecido pulmonar foi coletado para análise histológica posterior. A análise estatística foi realizada pela análise de variância com medidas repetidas (ANOVA) seguida por teste de Tukey. O grau de significância estabelecido foi de 5% (p<0,05). RESULTADOS: Houve diferença estatística significante quanto aos parâmetros ventilatórios, oxigenação sanguinea, burst oxidativo e análise histológica pulmonar dos grupos ALI e ALI+HS, quando comparados aos grupos Sham e HS. Níveis de IL-6 e IL-8 apresentaram-se mais elevados nos grupos ALI e ALI+HS, porém sem diferença estatística entre grupos...

BACKGROUND: Acute lung injury (ALI) caused by aspiration of gastric contents is not ununsual in patients with depression of airway reflexes. The potential anti-inflammatory effects of hypertonic saline 7.5% (HS) is still controversial on pulmonary response. OBJECTIVES: This study aimed to evaluate the potential anti-inflamatory effect of hypertonic saline (HS) in a swine model of hydrochloric acid (HCl) aspiration. METHODS: 32 pigs (n=32; 8/group) were randomly divided into the following groups: Sham, the animals were only anesthetized, ventilated and observed; HS, the animals received an 7.5% hypertonic saline infusion (4ml/kg); ALI, animals were submitted to ALI with HCl infusion; ALI+HS, animals were submitted to ALI with HCl infusion and treated with 7.5% hypertonic saline (4ml/kg). Hemodynamic and ventilatory parameters were measured. Blood samples were collected for blood gas analysis and plasma levels mensuration of TNF-?. Bronchoalveolar samples were also collected for IL-1, IL-6, IL-8, IL-10 and TNF-? cytokine mensuration and oxidative burst analysis. Lung tissue was collected for histological analysis. A parametrical analysis of variance with repeated measurement (ANOVA) followed by Tukey test was done. The significance level was set at 5% (p<0,05). RESULTS: There were estatistical differences regarding to ventilatory parameters, oxigenation, oxidative burst and pulmonary histological evaluation in ALI and ALI+HS groups, when compared to Sham and HS. IL-6 and IL-8 levels were higher in ALI and ALI+HS groups. However, no statistical difference were found between groups. CONCLUSION: The ALI model was effective to promote diffuse and heterogeneous lung injury. However, the group treated with 7.5% hypertonic saline did not presented statistical difference when compared to the non treated group regarding the evaluated parameters.

Minimum alveolar concentrations and hemodynamic effects of two different preparations of sevoflurane in pigs

BACKGROUND: Original sevoflurane (Sevo A) is made with water, while a generic sevoflurane (Sevocris) is produced with propylene glycol as a stabilizing additive. We investigated whether the original and generic sevoflurane preparations differed in terms of their minimum alveolar concentration (MAC) values and hemodynamic effects. METHODS: Sixteen pigs weighing 31.6±1.8 kg were randomly assigned to the Sevo A or Sevocris groups. After anesthesia induction via mask with the appropriate sevoflurane preparation (6 percent in 100 percent oxygen), the MAC was determined for each animal. Hemodynamic and oxygenation parameters were measured at 0.5 MAC, 1 MAC and 1.5 MAC. Histopathological analyses of lung parenchyma were performed. RESULTS: The MAC in the Sevo A group was 4.4±0.5 percent, and the MAC in the Sevocris group was 4.1±0.7 percent. Hemodynamic and metabolic parameters presented significant differences in a dose-dependent pattern as expected, but they did not differ between groups. Cardiac indices and arterial pressures decreased in both groups when the sevoflurane concentration increased from 0.5 to 1 and 1.5 MAC. The oxygen delivery index (DO2I) decreased significantly at 1.5 MAC. CONCLUSION: Propylene glycol as an additive for sevoflurane seems to be as safe as a water additive, at least in terms of hemodynamic and pulmonary effects.

Hyperkalemia accompanies hemorrhagic shock and correlates with mortality

OBJECTIVE: This study was designed to evaluate the effects of terlipressin versus fluid resuscitation with normal saline, hypertonic saline or hypertonic-hyperoncotic hydroxyethyl starch, on hemodynamics, metabolics, blood loss and short-term survival in hemorrhagic shock. METHOD: Twenty-nine pigs were subjected to severe liver injury and treated 30 min later with either: (1) 2 mg terlipressin in a bolus, (2) placebo-treated controls, (3) 4 mL/kg 7.5% hypertonic NaCl, (4) 4 mL/kg 7.2% hypertonic-hyperoncotic hydroxyethyl starch 200/0.5, or (5) normal saline at three times lost blood volume. RESULTS: The overall mortality rate was 69%. Blood loss was significantly higher in the hypertonic-hyperoncotic hydroxyethyl starch and normal saline groups than in the terlipressin, hypertonic NaCl and placebo-treated controls groups (p<0.005). Hyperkalemia (K>5 mmol/L) before any treatment occurred in 66% of the patients (80% among non-survivors vs. 22% among survivors, p=0.019). Post-resuscitation hyperkalemia occurred in 86.66% of non-survivors vs. 0% of survivors (p<0.001). Hyperkalemia was the first sign of an unsuccessful outcome for the usual resuscitative procedure and was not related to arterial acidemia. Successfully resuscitated animals showed a significant decrease in serum potassium levels relative to the baseline value. CONCLUSION: Hyperkalemia accompanies hemorrhagic shock and, in addition to providing an early sign of the acute ischemic insult severity, may be responsible for cardiac arrest related to hemorrhagic shock.