Background The two most prevalent causes of sudden cardiac death are ventricular fibrillation cardiac arrest （VFCA） and asphyxiation cardiac arrest （ACA）. Profound postresuscitation myocardial dysfunction has been...Background The two most prevalent causes of sudden cardiac death are ventricular fibrillation cardiac arrest （VFCA） and asphyxiation cardiac arrest （ACA）. Profound postresuscitation myocardial dysfunction has been demonstrated in both VFCA and ACA animal models. Our study aimed to characterize the two porcine models of cardiac arrest and postresuscitation myocardial metabolism dysfunction. Methods Thirty-two pigs were randomized into two groups. The VFCA group （n=16） were subject to programmed electrical stimulation and the ACA group （n=16） underwent endotracheal tube clamping to induce cardiac arrest （CA）. Once induced, CA remained untreated for a period of 8 minutes. Two minutes following initiation of cardiopulmonary resuscitation （CPR）, defibrillation was attempted until return of spontaneous circulation （ROSC） was achieved or animals died. To assess myocardial metabolism, 18F-FluoroDeoxyGlucose Positron Emission Tomography was performed at baseline and 4 hours after ROSC. Results ROSC was 100% successful in VFCA and 50% successful in ACA. VFCA had better mean arterial pressure and cardiac output after ROSC than ACA. Arterial blood gas analysis indicated more detrimental metabolic disturbances in ACA compared with VFCA after ROSC （ROSC 0.5 hours, pH： 7.01±0.06 vs. 7.21±0.03, P〈0.01; HCO3： （15.83±2.31 vs. 20.11±1.83） mmol/L, P〈0.01; lactate： （16.22±1.76 vs. 5.84±1.44） mmol/L, P〈0.01）. Myocardial metabolism imaging using Positron Emission Tomography demonstrated that myocardial injuries after ACA were more severe and widespread than after VFCA at 4 hours after ROSC （the maximum standardized uptake value of the whole left ventricular： 1.00±0.17 vs. 1.93±0.27, P〈0.01）. Lower contents of myocardial energy metabolism enzymes （Na＊-K＊-ATPase enzyme activity, Ca2＊- ATPase enzyme activity, superoxide dismutase and phosphodiesterase） were found in ACA relative to VFCA. Conclusions Compared with VFCA, ACA causes more severe myocardium injury and metabolism hindrance, therefore they should be treated as different pathological entities.展开更多
Flamethrowers are widely considered one of warfare’s most controversial weapons and are capable of inflicting gruesome physical injuries and intense psychological trauma.Despite being the last of the major combatants...Flamethrowers are widely considered one of warfare’s most controversial weapons and are capable of inflicting gruesome physical injuries and intense psychological trauma.Despite being the last of the major combatants in World WarⅡ(WWⅡ)to develop them,the U.S.military quickly became the most frequent and adept operator of portable flamethrowers.This gave the U.S.military ample opportunity to observe the effects of flamethrowers on enemy soldiers.However,while most people in modern times would consider immolation by flamethrower to be an unnecessarily painful and inhumane way to inflict casualties,immolation was,at one point during WWⅡ,referred to as"mercy killing"by the U.S.Chemical Warfare Service(CWS).This mischaracterization arose from a series of firsthand accounts describing what were believed to be quick,painless,and unmarred deaths,as well as from a poor and incomplete understanding of flamethrower lethality.As a result,indirect mechanisms such as hypoxia and carbon monoxide poisoning were generally absent from accounts of the flamethrower’s fatal effects.It was not until several years after flamethrowers were introduced to the frontlines that the CWS and National Defense Research Committee(NDRC)conducted a series of tests to better understand the physiological and toxicological effects of flamethrowers.This article examines how the initial absence of scientific data on the physiologic effects of flamethrowers led to an inaccurate understanding of their lethality,and bizarre claims that one of history’s most horrific instruments of war was considered one of the more"humane"weapons on the battlefield.展开更多
Cerebral blood flow of 10 asphyxiated term newborns was continuously measured during the first 7 days of life and compared with that of 10 normal term infants by CDI. Frequency spectrum and blood flow variables in the...Cerebral blood flow of 10 asphyxiated term newborns was continuously measured during the first 7 days of life and compared with that of 10 normal term infants by CDI. Frequency spectrum and blood flow variables in the anterior, middle and posterior cerebral arteries were studied. The results showed evidently lower systolic amplitude in patients than that in normal subjects. End diastolic amplitude was zero in part of vessels, and values of bloed flow variables were all lower in day 1 of the life as compared with the control groups. Frequency spectrum recovered to normal patterns in 9 survived infants in day 2. but blood flow variables recovered to normal by day 7. Values of resistance index (RI) rose to 1 in some vessels of moderate hypoxic ischemic encephalopathy (HIE) infants and stayed at 1 in the severe HIE infants. It is concluded that low CBF plays a key role in brain damage of post-asphyxiated newborns and RI may be an important parameter in the evaluation prognosis.展开更多
文摘Background The two most prevalent causes of sudden cardiac death are ventricular fibrillation cardiac arrest （VFCA） and asphyxiation cardiac arrest （ACA）. Profound postresuscitation myocardial dysfunction has been demonstrated in both VFCA and ACA animal models. Our study aimed to characterize the two porcine models of cardiac arrest and postresuscitation myocardial metabolism dysfunction. Methods Thirty-two pigs were randomized into two groups. The VFCA group （n=16） were subject to programmed electrical stimulation and the ACA group （n=16） underwent endotracheal tube clamping to induce cardiac arrest （CA）. Once induced, CA remained untreated for a period of 8 minutes. Two minutes following initiation of cardiopulmonary resuscitation （CPR）, defibrillation was attempted until return of spontaneous circulation （ROSC） was achieved or animals died. To assess myocardial metabolism, 18F-FluoroDeoxyGlucose Positron Emission Tomography was performed at baseline and 4 hours after ROSC. Results ROSC was 100% successful in VFCA and 50% successful in ACA. VFCA had better mean arterial pressure and cardiac output after ROSC than ACA. Arterial blood gas analysis indicated more detrimental metabolic disturbances in ACA compared with VFCA after ROSC （ROSC 0.5 hours, pH： 7.01±0.06 vs. 7.21±0.03, P〈0.01; HCO3： （15.83±2.31 vs. 20.11±1.83） mmol/L, P〈0.01; lactate： （16.22±1.76 vs. 5.84±1.44） mmol/L, P〈0.01）. Myocardial metabolism imaging using Positron Emission Tomography demonstrated that myocardial injuries after ACA were more severe and widespread than after VFCA at 4 hours after ROSC （the maximum standardized uptake value of the whole left ventricular： 1.00±0.17 vs. 1.93±0.27, P〈0.01）. Lower contents of myocardial energy metabolism enzymes （Na＊-K＊-ATPase enzyme activity, Ca2＊- ATPase enzyme activity, superoxide dismutase and phosphodiesterase） were found in ACA relative to VFCA. Conclusions Compared with VFCA, ACA causes more severe myocardium injury and metabolism hindrance, therefore they should be treated as different pathological entities.
文摘Flamethrowers are widely considered one of warfare’s most controversial weapons and are capable of inflicting gruesome physical injuries and intense psychological trauma.Despite being the last of the major combatants in World WarⅡ(WWⅡ)to develop them,the U.S.military quickly became the most frequent and adept operator of portable flamethrowers.This gave the U.S.military ample opportunity to observe the effects of flamethrowers on enemy soldiers.However,while most people in modern times would consider immolation by flamethrower to be an unnecessarily painful and inhumane way to inflict casualties,immolation was,at one point during WWⅡ,referred to as"mercy killing"by the U.S.Chemical Warfare Service(CWS).This mischaracterization arose from a series of firsthand accounts describing what were believed to be quick,painless,and unmarred deaths,as well as from a poor and incomplete understanding of flamethrower lethality.As a result,indirect mechanisms such as hypoxia and carbon monoxide poisoning were generally absent from accounts of the flamethrower’s fatal effects.It was not until several years after flamethrowers were introduced to the frontlines that the CWS and National Defense Research Committee(NDRC)conducted a series of tests to better understand the physiological and toxicological effects of flamethrowers.This article examines how the initial absence of scientific data on the physiologic effects of flamethrowers led to an inaccurate understanding of their lethality,and bizarre claims that one of history’s most horrific instruments of war was considered one of the more"humane"weapons on the battlefield.
文摘Cerebral blood flow of 10 asphyxiated term newborns was continuously measured during the first 7 days of life and compared with that of 10 normal term infants by CDI. Frequency spectrum and blood flow variables in the anterior, middle and posterior cerebral arteries were studied. The results showed evidently lower systolic amplitude in patients than that in normal subjects. End diastolic amplitude was zero in part of vessels, and values of bloed flow variables were all lower in day 1 of the life as compared with the control groups. Frequency spectrum recovered to normal patterns in 9 survived infants in day 2. but blood flow variables recovered to normal by day 7. Values of resistance index (RI) rose to 1 in some vessels of moderate hypoxic ischemic encephalopathy (HIE) infants and stayed at 1 in the severe HIE infants. It is concluded that low CBF plays a key role in brain damage of post-asphyxiated newborns and RI may be an important parameter in the evaluation prognosis.
