Contribution of myoglobin-induced increases in vascular resistance to shock decompensation in experimental Crush-syndrome in anesthetized rats

Cardiovascular events in crush syndrome: on-site therapeutic strategies and pharmacological investigations

Crush syndrome often occurs after severe crush injury caused by disasters or accidents, and is associated with high mortality and poor prognosis. Cardiovascular complications, such as cardiac arrest, hypovolemic shock, and hyperkalemia-related cardiac dysfunction, are the primary causes of on-site death in crush syndrome. Prehospital evaluation, together with timely and correct treatment, is of great benefit to crush syndrome patients, which is difficult in most cases due to limited conditions. Based on current data and studies, early fluid resuscitation remains the most important on-site treatment for crush syndrome. Novel solutions and drugs used in fluid resuscitation have been investigated for their effectiveness and benefits. Several drugs have proven effective for the prevention or treatment of cardiovascular complications in crush syndrome, such as hypovolemic shock, hyperkalemia-induced cardiac complications, myocardial ischemia/reperfusion injury, ventricular dysfunction, and coagulation disorder experimentally. Moreover, these drugs are beneficial for other complications of crush syndrome, such as renal dysfunction. In this review, we will summarize the existing on-site treatments for crush syndrome and discuss the potential pharmacological interventions for cardiovascular complications to provide clues for clinical therapy of crush syndrome.

Extreme Rhabdomyolysis, Acute Renal Failure, and Protracted Ileus in a Case of Legionella Pneumonia

A 53-year-old man developed a Legionella pneumophila pneumonia complicated by rhabdomyolysis, acute kidney injury, and protracted ileus. Risk factors were smoking and chronic alcoholism, but the patient had no history of previous abdominal surgery. Hemodialysis was required for a period of 5 weeks with a full renal recovery. Pneumonia required respiratory support but for a limited period of 6 days. The protracted course of the ileus led to explorative laparotomy despite negative computed tomography findings. No cause of mechanical obstruction was found at surgery and common etiologies of intestinal obstruction were excluded. Parenteral nutrition was needed for a total of 4 weeks, before recovery of intestinal motility. This case illustrates the apparent discrepancy between the pulmonary symptoms and the extrapulmonary manifestations that could be seen as a consequence of an exaggerated immune response.

Plasma cytokine expression after lower-limb compression in rats

Objectives

Muscle injury due to crushing (muscle compression injury) is associated with systemic manifestations known as crush syndrome. A systemic inflammatory reaction may also be triggered by isolated muscle injury. The aim of this study was to investigate the plasma levels of interleukins (IL) 1, 6 and 10 and tumor necrosis factor alpha (TNF-α), which are markers for possible systemic inflammatory reactions, after isolated muscle injury resulting from lower-limb compression in rats.

Methods

Male Wistar rats were subjected to 1 h of compression of their lower limbs by means of a rubber band. The plasma levels of IL 1, 6 and 10 and TNF-α were measured 1, 2 and 4 h after the rats were released from compression.

Results

The plasma levels of IL 10 decreased in relation to those of the other groups, with a statistically significant difference (p < 0.05). The method used did not detect the presence of IL 1, IL 6 or TNF-α.

Conclusion

Our results demonstrated that the changes in plasma levels of IL 10 that were found may have been a sign of the presence of circulating interleukins in this model of lower-limb compression in rats.

Release of redox-active iron by muscle crush trauma: no liberation into the circulation

After major skeletal muscle trauma, the iron-containing protein myoglobin and diverse other intracellular metabolites are liberated into the circulation from injured myocytes. Because chelatable iron should also be present in skeletal muscle cells, this redox-active, not tightly bound iron should be released from injured muscle tissue in addition to myoglobin and potentially account for oxidative tissue damage. The current study demonstrates in vitro the existence of 5 muM chelatable iron within the supernatant of a 1:10 homogenate of rat gastrocnemius muscle. This iron was almost exclusively associated with macromolecules greater than 30 kDa, most likely proteins. Presumably because of this association, only part of the chelatable iron could be scavenged by added apotransferrin. The chelatable iron was redox-active and thus responsible for the formation of thiobarbituric acid-reactive substances (TBARS) within the muscle homogenate. Correspondingly, using an in vivo model of closed trauma to the rat gastrocnemius muscle, a local TBARS formation in the damaged muscle tissue could be detected. Muscle trauma significantly increased plasma creatine kinase and myoglobin levels; however, no increase in serum non-transferrin-bound iron could be observed. Likewise, the serum parameters of iron-induced oxidative damage, TBARS, and protein carbonyls did not significantly increase after trauma. In conclusion, chelatable, redox-active iron is locally released by muscle destruction and responsible for lipid peroxidation within the damaged tissue. However, the liberation of chelatable iron into the circulation and its contribution to oxidative alterations of serum lipids and proteins could not be confirmed.

Role of tissue disorder markers in the evaluation of disease progress and outcome prediction: a prospective cohort study in non-cardiac critically ill patients

BACKGROUND

Acute Physiology and Chronic Health Evaluation (APACHE) has a remarkable association with clinical syndrome, life expectancy, and length of ward stay. But the defects are obvious. It is crucial to detect an effective and convenient evaluation method to monitor disease progress and predict outcome.

OBJECTIVE

To determine whether myoglobin (Mb) and other five tissue disorder biomarkers, troponin-I, creatine-kinase, creatine kinase-muscle brain, aspartate aminotransferase, and lactate dehydrogenase are independent predictors of disease progress and mortality in non-cardiac critical illness.

METHODS

A prospective study with 179 patients admitted to the Intensive Care Unit was conducted. All serum tissue disorder markers and APACHE-II score were measured within 24  hr of admission.

RESULTS

All the six biomarkers were significantly correlated with disease severity stratified by APACHE-II and outcome. Serial blood samples were taken from 17 patients on detection of two new organs failure. The occurrence of organs failure was significantly associated with the elevation of Mb, troponin-I, and APACHE-II. Multivariate analysis demonstrated that elevated Mb was the principal risk factor related to mortality either during hospitalization or 180-day followup. Kaplan-Meier method and log-rank test also showed that patients with elevated Mb levels had significantly shorter survival. The mortality was higher in patients with both Mb>500  ng/ml and APACHE-II>20 than in those with only Mb>500  ng/ml or APACHE-II>20.

CONCLUSION

All the six tissue disorder markers are predictors of disease severity, organ failure, and outcome in non-cardiac critically illness. Among them, Mb plays a pivotable role. The combined use of Mb and APACHE-II suggest an effective method to determine the outcome of critical ill syndrome.

SYNERGISTIC EFFECTS OF RECOMBINANT HUMAN SOLUBLE THROMBOMODULIN AND FLUID-VOLUME RESUSCITATION IN A RAT LETHAL CRUSH INJURY MODEL

Severe crush injury results in a high mortality rate because of acute circulatory failure and hyperkalemia. The purpose of this study was to evaluate whether administration of prophylactic-recombinant human soluble thrombomodulin (rhsTM) and/or fluid-volume resuscitation before reperfusion attenuates severe crush injury in rats. Both hindlimbs of anesthetized rats were compressed for 6 h under blocks weighing 3.5 kg each, followed by 3 h of reperfusion. In the first group, fluid resuscitation with normal saline (1 mL/kg/h) was performed throughout the experiment. In the second group, volume resuscitation treatment with normal saline (10 mL/kg/h) was initiated 60 min before the end of the crush period and was continued until the end of the experiment. In the third group, normal saline-resuscitation treatment plus rhsTM (3 mg/kg) was performed. In the fourth group, volume resuscitation treatment plus rhsTM was performed. Blood samples were collected 6 h after the end of the crush period. Complete blood count and platelets were measured. In addition, serum lactate, base deficit, serum potassium, creatine phosphokinase, blood urea nitrogen, creatinine, myoglobin, and some cytokines were evaluated. In another experiment, survival of each group was monitored for 72 h after the end of the crush period. Combined administration of rhsTM and volume resuscitation significantly decreased hemoconcentration and hyperkalemia. The serum interleukin-6 level and mortality were also significantly improved in the combination group compared with those in the other groups. We conclude that prophylactic combination of rhsTM administration and volume resuscitation may be an effective therapy for severe crush injury.