A model of hemorrhagic shock and acute lung injury in Landrace-Large White Swine.

Traumatic injury is a leading cause of death worldwide for people between 5 and 44 y of age, and it accounts for 10% of all deaths. The incidence of acute lung injury, a life-threatening complication in severely injured trauma patients remains between 30% and 50%. This study describes an experimental protocol of volume-controlled hemorrhage in Landrace-Large White swine. The experimental approach simulated the clinical situation associated with hemorrhagic shock in the trauma patient while providing controlled conditions to maximize reproducibility. The duration of the protocol was 8 h and was divided into 5 distinct phases-stabilization, hemorrhage, maintenance, resuscitation, and observation-after which the swine were euthanized. Lung tissue samples were analyzed histologically. All swine survived the protocol. The hemodynamic responses accurately reflected those seen in humans, and the development of acute lung injury was consistent among all swine. This experimental protocol of hemorrhagic shock and fluid resuscitation in Landrace-Large White swine may be useful for future study of hemorrhagic shock and acute lung injury.

Hydroxyethyl starch 6% (130/0.4) ameliorates acute lung injury in swine hemorrhagic shock.

BACKGROUND: Traumatic hemorrhage induces acute lung injury. The aim of this study was to assess whether lactated Ringer's solution or 6% hydroxyethyl starch 130/0.4 would have different effects on acute lung injury following hemorrhagic shock. METHODS: Twenty healthy pigs (19 ± 2 kg) were subjected to hemorrhage and were randomly allocated to two groups: Group A (10 pigs) who received lactated Ringer's solution and Group B (10 pigs) who received hydroxyethyl starch 130/0.4. Hemodynamic response and serum lactate were measured at predetermined phases. Four hours after fluid resuscitation animals were euthanized. Lungs were harvested, and tissue samples were collected. Focal thickening of the alveolar membranes, vascular congestion, number of activated neutrophils, alveolar edema, interstitial neutrophil infiltration, intraalveolar infiltration, and alveolar hemorrhage were assessed. Each feature was given a score from 0 to 3 (0 = absence, 3 = severe). The wet/dry ratio was also calculated, and with the use of Evans blue dye extravasation method, capillary permeability was assessed. RESULTS: The total histology score of Group A differed significantly from that of Group B, being significantly lower in Group B animals P = 0.048. The wet/dry weight ratio was significantly higher in the lactated Ringer's group (median [range]) (Group A, 5.1 [0.5]; Group B, 4.9 [0.3]; P = 0.009). The Evans blue dye extravasation method was utilized to study the lung capillary permeability. The animals in Group B showed a marked reduction in microvascular capillary permeability compared with the animals in Group A (Group A, 58.5 [21] mg/g; Group B, 51.5 [14] mg/g; P = 0.017). CONCLUSIONS: Our study indicates that resuscitation after hemorrhagic shock with hydroxyethyl starch 130/0.4 led to less lung edema and less microvascular permeability in this swine model.

Combination pharmacotherapy in the treatment of experimental cardiac arrest.

STUDY OBJECTIVES: Full recovery after cardiopulmonary resuscitation (CPR) is poor. We hypothesized that the coadministration of epinephrine, a beta-blocker such as atenolol, and a calcium sensitizer such as levosimendan during CPR would improve survival and postresuscitation myocardial function. METHODS: Ventricular fibrillation was induced in 60 piglets, which were left untreated for 8 minutes before attempted resuscitation. Animals were randomized into 4 groups (n = 15), to receive epinephrine (group E), epinephrine + atenolol (group E + A), epinephrine + levosimendan (group E + L) and epinephrine + atenolol + levosimendan (group E + A + L) during CPR. Electrical defibrillation was attempted 2 minutes after drug administration. RESULTS: Five animals in group E survived for 48 hours in comparison to 8 animals in groups E + A and E + L and 12 animals in group E + A + L. Postresuscitation cardiac output was significantly better in the animals of group E + A + L. Troponin I remained significantly lower in groups E + A and E + A + L. Serum astroglial protein (S-100) and neuron-specific enolase values in group E + L and E + A + L were statistically lower than those measured in groups E and E + A during the entire observation period. The neurologic alertness score was higher in group E + A + L compared to groups E and E + A. CONCLUSIONS: The administration of a drug combination of epinephrine + atenolol + levosimendan, when given during CPR, in a pig model of cardiac arrest, results in improved 48-hour survival and improves postresuscitation cardiac function.

Vasopressin and epinephrine in the treatment of cardiac arrest: an experimental study.

BACKGROUND: Epinephrine remains the drug of choice for cardiopulmonary resuscitation. The aim of the present study is to assess whether the combination of vasopressin and epinephrine, given their different mechanisms of action, provides better results than epinephrine alone in cardiopulmonary resuscitation. METHODS: Ventricular fibrillation was induced in 22 Landrace/Large-White piglets, which were left untreated for 8 minutes before attempted resuscitation with precordial compression, mechanical ventilation and electrical defibrillation. Animals were randomized into 2 groups during cardiopulmonary resuscitation: 11 animals who received saline as placebo (20 ml dilution, bolus) + epinephrine (0.02 mg/kg) (Epi group); and 11 animals who received vasopressin (0.4 IU/kg/20 ml dilution, bolus) + epinephrine (0.02 mg/kg) (Vaso-Epi group). Electrical defibrillation was attempted after 10 minutes of ventricular fibrillation. RESULTS: Ten of 11 animals in the Vaso-Epi group restored spontaneous circulation in comparison to only 4 of 11 in the Epi group (p = 0.02). Aortic diastolic pressure, as well as, coronary perfusion pressure were significantly increased (p < 0.05) during cardiopulmonary resuscitation in the Vaso-Epi group. CONCLUSION: The administration of vasopressin in combination with epinephrine during cardiopulmonary resuscitation results in a drastic improvement in the hemodynamic parameters necessary for the return of spontaneous circulation.