Delayed Resuscitation With ECMO For Hemorrhagic Shock Significantly Alleviate Lung Injury In Rabbits

Backgrounds and Objective：Hemorrhagic shock was common in clinic，whichcaused by trauma frequently. In the early，crystal and whole blood is benificial for therecovery of hemorrhagic shock. However, when objective conditions were restricted，patients could not be resuscitated in time and result in acute lung injury，even eruptrespiratory failure or multiple organ failure simultaneously. With delaying of the shock，theefficacy of traditional approach of whole blood plus crystal recovery become worse andworse. What’s more, it could aggravate the damage of pulmonary. The using of mechanicalventilation treatment scheme not only plays poor function in improving the pulmonaryventilation,but also aggravated the acute lung injury and increased the risk of death ratefrom shock due to the damage of airway caused by mechanical ventilation airflowpressure.Hence，in the wars in Vietnam, the wars in Afghanistan and Iraq, plenty ofhemorrhagic shock trauma patients encountered injuries and deaths.In recent years, plenty of studies were reported about hemorrhagic shock,but the shockwere sustained between30-90minutes. These studies indicated that early shock which wasmanaged by the method of crystal plus whole blood recovery is extremely effective.However, there were plenty of shock patients who taken up to3hours of time in hospital,and the transit time may be longer in war time. These patients probable suffer fail recoveryand the survival rate is quite low. It exerts great influence in treatment of shock.As a novel means of life supporting, ECMO had achieved great success for patientswith acute lung injury complicating with ARDS or cardiac shock.Following thedevelopment of the ECMO technology, the consumption of anticoagulant reduced greatly inthe process of the clinical application of ECMO, anticoagulant is not necessary under thecondition of the larger flow velocity. It will greatly extend the application of the ECMO intrauma patients. This study established rabbit uncontrolled hemorrhagic shock based on the way of rabbit femoral artery bleeding,and maintain the state of shock3hours beforeresuscitation. This can simulate delayed recovery of wartime or major natural disasters well.This study recovery hemorrhagic shock lingeringly adopting the ECMO combined wholeblood plus crystal method，and investigated the efficacy of ECMO in delaying the recoveryof lung function of rabbits hemorrhagic shock.Methods:1. Bleeding from femoral artery to the mean arterial pressure(MAP)40mmHg andmaintain the MAP (35-40) mmHg3hours established uncontrolled hemorrhagic shockdelayed recovery model. The delayed recovery experiment rabbits were randomly dividedinto three groups, eight of each group. The first group does not attempt resuscitation；thesecond group was recovered by the crystal and whole blood recovery method；the thirdgroup was recovered by the ECMO combined with crystal plus whole blood recoverymethod. Hemodynamics was observed among groups after2hours recovery. And reservesamples after animal euthanasia to detection of related indicators.2. The variation of oxygen partial pressure were evaluated by the ABG before andafter the shock and resuscitation.3. The protein concentrations in alveolar lavage after the centrifugal was detected bythe method of coomassie brilliant blue to evaluate lung permeability changes.4. HE staining (Histochemical stain) was employed to observe pathological changesof each lung tissue.5. Scanning electron microscopy was used to observe the microstructure change oftype II epithelial cells in lung tissu.6. Peroxidase (MPO) of lung tissue was detected the by enzyme-linkedimmunosorbent assay (ELISA).7. DNA rupture in situ end labeling method (TUNEL) were used to detected theapoptosis of lung tissue cells,and compared the number of apoptotic cells among groupsunder the microscope.8. The expression of Cysteine protease3were detected by the Western blot.9. Statistical analysis: SPSS17.0software was used for statistical analysis. Results:1. The rabbit model of uncontrolled hemorrhagic shock and delay3hours recoverywas established successfully.2. The hemodynamic indicators including the mean arterial pressure of the ECMOrecovery group improved after2hours obviously, which compared withthe fluidresuscitation group and unresuscitation group(p<0.05，p<0.01).3. Observation of HE staining of lung tissue by light microscope after recovery：thefluid resuscitation group pathological damage was worse，which compared with the fluidresuscitation group and unresuscitation group.4. According to the ABG,the arterial partial pressure were elevated in ECMOresuscitation group compared with the fluid resuscitation group and unresuscitationgroup(p<0.05).5. Observation by electron microscope, the ECMO recovery group was relievedcompared with the fluid resuscitation group and unresuscitation group.6. The MPO of lung tissue was detected by ELISHA: the ECMO recovery group wasreduced compared with the fluid resuscitation group and unresuscitation group(p<0.05)..7. Coomassie brilliant blue test each lung lavage protein concentration: the proteinconcentration of ECMO recovery group was lower compared with the fluid resuscitationgroup and unresuscitation group(p<0.05).8. Detection cell apoptosis in pulmonary tissues by TUNEL method: the apoptosis ofECMO recovery group decreased compared with the fluid resuscitation group andunresuscitation group.9. According to the expression of Cysteine protease3by Western blot.the expressionof Cysteine protease3were lower than the Shock recovery group and fluid resuscitationgroupConclusion:1. Successfully established the rabbit model of uncontrolled hemorrhagic shock anddelay recovery2. The ECMO combined whole blood and crystal resuscitation is more benificialto restore and maintain hemodynamic for the rabbits that suffer hemorrhagic shock and delayrecovery.3. The ECMO combined whole blood and crystal resuscitation can significantlyreduced pulmonary injury of rabbits that suffered hemorrhagic shock and delayed recovery.