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Keith G Lurie - One of the best experts on this subject based on the ideXlab platform.
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Vital Organ Blood Flow with the impedance threshold device.
Critical Care Medicine, 2006Co-Authors: Tom P Aufderheide, Keith G LurieAbstract:Objective: The purpose of this study is to review cardiopulmonary resuscitation hemodynamics and vital Organ Blood Flow in animal models with the use of the impedance threshold device (ITD) and to correlate these findings with the results of human clinical trials. Results: Animal studies have demonstrated near normalization of cerebral Blood Flow and an increase between 50% and 100% in cardiac Blood Flow with use of the ITD. Coincident coronary perfusion pressure is significantly increased with the ITD. Results of human clinical trials generally reflect the data seen in animal models, with near normal Blood pressure during active compression-decompression cardiopulmonary resuscitation and the ITD, near doubling of Blood pressure with standard cardiopulmonary resuscitation plus the ITD, and significantly increased short-term survival rates. Conclusions: Improved vital Organ perfusion with ITD use during cardiopulmonary resuscitation is an important advance in resuscitation. Incorporation of the ITD into protocols that improve other aspects of the care of patients during cardiac arrest and after successful resuscitation should result in further benefit from the ITD. (Crit Care Med 2006; 34[Suppl.]:S466-S473)
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Vital Organ Blood Flow with the impedance threshold device.
Critical care medicine, 2006Co-Authors: Tom P Aufderheide, Keith G LurieAbstract:The purpose of this study is to review cardiopulmonary resuscitation hemodynamics and vital Organ Blood Flow in animal models with the use of the impedance threshold device (ITD) and to correlate these findings with the results of human clinical trials. Animal studies have demonstrated near normalization of cerebral Blood Flow and an increase between 50% and 100% in cardiac Blood Flow with use of the ITD. Coincident coronary perfusion pressure is significantly increased with the ITD. Results of human clinical trials generally reflect the data seen in animal models, with near normal Blood pressure during active compression-decompression cardiopulmonary resuscitation and the ITD, near doubling of Blood pressure with standard cardiopulmonary resuscitation plus the ITD, and significantly increased short-term survival rates. Improved vital Organ perfusion with ITD use during cardiopulmonary resuscitation is an important advance in resuscitation. Incorporation of the ITD into protocols that improve other aspects of the care of patients during cardiac arrest and after successful resuscitation should result in further benefit from the ITD.
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Combination drug therapy with vasopressin, adrenaline (epinephrine) and nitroglycerin improves vital Organ Blood Flow in a porcine model of ventricular fibrillation.
Resuscitation, 2002Co-Authors: Keith G Lurie, Wolfgang G. Voelckel, Demos Iskos, Scott Mcknite, Todd M. Zielinski, Atsushi Sugiyama, Volker Wenzel, David G. Benditt, Karl H. LindnerAbstract:Abstract There is increasing evidence that the combination of epinephrine (adrenaline) with vasopressin may be superior to either epinephrine or vasopressin alone for treatment of cardiac arrest. However, the optimal combination, and dosage of cardiovascular drugs to minimize side effects, and to improve outcome has yet to be found. We therefore evaluated whether the combination of vasopressin plus epinephrine plus nitroglycerin (EVN), would improve vital Organ Blood Flow during cardiopulmonary resuscitation (CPR) when compared with epinephrine (EPI) alone. After 4 min of ventricular fibrillation (VF) and 4 min of standard CPR, pigs were randomized to the combination of epinephrine (45 μg/kg) plus vasopressin (0.4 U/kg) plus nitroglycerin (7.5 μg/kg; n =12), or epinephrine (40 μg/kg; n =12) alone. Cerebral and myocardial Blood Flow was measured with radiolabeled microspheres. Defibrillation was attempted after 19 min of VF including 15 min of CPR. Mean±SEM coronary perfusion pressures were significantly ( P P P =N.S.). In conclusion, the combination of EVN significantly improved vital Organ Blood Flow during CPR compared with EPI alone. Addition of nitroglycerin to the combination of low dose epinephrine with vasopressin during cardiac arrest may be beneficial.
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vasopressin improves vital Organ Blood Flow during closed chest cardiopulmonary resuscitation in pigs
Circulation, 1995Co-Authors: Karl H. Lindner, Andreas W Prengel, Ernst G Pfenninger, Ingrid M Lindner, Hansulrich Strohmenger, Michael K Georgieff, Keith G LurieAbstract:Background This study was designed to compare the effects of epinephrine with those of vasopressin on vital Organ Blood Flow during closed-chest cardiopulmonary resuscitation (CPR) in a pig model of ventricular fibrillation. Methods and Results Vasopressin was compared with epinephrine by randomly allocating 28 pigs to receive either 0.2 mg/kg epinephrine (n=7), 0.2 U/kg vasopressin (low dose) (n=7), 0.4 U/kg vasopressin (medium dose) (n=7), or 0.8 U/kg vasopressin (high dose) (n=7) after 4 minutes of ventricular fibrillation and 3 minutes of closed-chest CPR. Left ventricular myocardial Blood Flow, determined by use of radiolabeled microspheres during CPR, before and then 90 seconds and 5 minutes after drug administration was 17±2, 43±5, and 22±3 mL · min−1 · l00 g−1 (mean±SEM) in the epinephrine group; 18±2, 50±6, and 29±3 mL · min−1 · 100 g−1 in the low-dose vasopressin group; 17±3, 52±8, and 52±6 mL · min−1 · 100 g−1 in the medium-dose vasopressin group; and 18±2, 95±9, and 57±6 mL · min−1 · 100 g−1 i...
Rinaldo Bellomo - One of the best experts on this subject based on the ideXlab platform.
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The effect of normal saline resuscitation on vital Organ Blood Flow in septic sheep
Intensive care medicine, 2006Co-Authors: Li Wan, Rinaldo Bellomo, Clive N. MayAbstract:Objective To study the effect of resuscitation with normal saline on vital Organ Blood Flow and renal function in sepsis.
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norepinephrine and vital Organ Blood Flow during experimental hyperdynamic sepsis
Intensive Care Medicine, 2003Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:To study the effect of norepinephrine (NE) infusion on cerebral, coronary, renal and mesenteric Blood Flow during sepsis. Randomised placebo-controlled animal trial in the animal laboratory of university physiology institute. Seven merino cross-ewes. Chronic implantation of Flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous bolus of E. coli (3×109). After the onset of hyperdynamic sepsis sheep were randomly allocated to either NE (0.4 µg kg−1 min−1) or placebo for 6 h. E. coli induced hypotension, fever, oliguria, tachycardia and tachypnoea. It increased cardiac output and renal, mesenteric and coronary Blood Flows. Sagittal Flow remained unchanged. Compared to placebo NE infusion restored mean arterial Blood pressure and further increased cardiac output. The increases in renal, mesenteric and coronary Blood Flow were unaffected. Sagittal Flow was also unaltered. Compared to placebo NE increased myocardial performance, mean urine output and creatinine clearance at 2 h. We conclude that hyperdynamic sepsis increases Blood Flow to heart, gut and kidney and that NE further increases cardiac output, Blood pressure, myocardial performance, and urine output and creatinine clearance while maintaining regional Blood Flow.
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Vital Organ Blood Flow During Hyperdynamic Sepsis
Chest, 2003Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:Objectives: To develop a nonlethal model of hyperdynamic sepsis, and to measure vital Organ Blood Flows in this setting. Design: Randomized crossover animal study. Setting: Animal laboratory of university-affiliated physiology institute. Subjects: Seven Merino cross sheep. Interventions: Surgical implantation of transit-time Flow probes around sagittal sinus and circumflex coronary, superior mesenteric, and left renal arteries, and of an electromagnetic Flow probe around the ascending aorta. After recovery, randomization to either 6 h of observation under normal conditions (control) or 6 h of observation after the induction of hyperdynamic nonlethal sepsis (sepsis), with each animal crossing over to the other treatment after a 2-week interval. Measurements and main results: Injection of Escherichia coli induced nonlethal hyperdynamic sepsis within 5 to 6 h with hypotension (mean arterial pressure [± SD], 85 ± 7 mm Hg vs 69 ± 8 mm Hg), increased cardiac output (4.0 ± 0.9 L/min vs 7.2 ± 1.2 L/min), tachycardia (60 ± 10 beats/min vs 160 ± 15 beats/min), fever, oliguria, and tachypnea. Compared to control animals, hyperdynamic sepsis increased renal (330 ± 101 mL/min vs 214 ± 75 mL/min), mesenteric (773 ± 370 mL/min vs 516 ± 221 mL/min), and coronary (54 ± 24 mL/min vs 23 ± 10 mL/min) Blood Flow (p Conclusions: Injection of E coli induced hyperdynamic nonlethal sepsis. During such hyperdynamic sepsis, Blood Flow to heart, gut, and kidney was markedly increased; however, Organ dysfunction developed. We speculate that global ischemia may not be the principal mechanism of vital Organ dysfunction in hyperdynamic sepsis.
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norepinephrine and vital Organ Blood Flow
Intensive Care Medicine, 2002Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:Abstract Objective. To test whether norepinephrine (NE) infusion at 0.4 µg kg–1 min–1 adversely affects regional Blood Flow in the normal mammalian circulation. Design and setting. Randomized cross-over experimental animal study in a university-affiliated physiology institute. Subjects. Six merino ewes. Interventions. Staged insertion of transit-time Flow probes around the ascending aorta and circumflex coronary, superior mesenteric and left renal arteries. In conscious animals with chronically embedded Flow probes randomization to either 6 h of placebo (saline) or drug (NE at 0.4 µg kg–1 min–1). Measurements and results. Compared to placebo, NE significantly increased mean arterial pressure (84.4 vs. 103.8 mmHg), heart rate (61.0 vs. 74.6 bpm) and cardiac output (3.76 vs. 4.78 l/min). These changes were associated with an increase in coronary Blood Flow (24.2 vs. 37.4 ml/min) and renal Blood Flow (215.2 vs. 282.0 ml/min) but no change in mesenteric Blood Flow. The increase in renal and coronary Blood Flow was associated with an increase in regional conductance (regional vasodilatation), while mesenteric conductance fell (mesenteric vasoconstriction). Urine output (91±17 vs. 491±360 ml/h) and creatinine clearance (61±18 vs. 89±12 ml/min) increased during NE infusion. Conclusions. NE infusion does not induce vital Organ ischaemia in the normal mammalian circulation. Furthermore, it results in a significant increase in coronary and renal Blood Flow with a concomitant improvement in urine output and creatinine clearance.
F. J. Carmichael - One of the best experts on this subject based on the ideXlab platform.
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Hemodynamic and Organ Blood Flow responses to halothane and sevoflurane anesthesia during spontaneous ventilation.
Anesthesia and analgesia, 1992Co-Authors: Mark W. Crawford, Jerrold Lerman, Victor Saldivia, F. J. CarmichaelAbstract:This study compared systemic hemodynamic and Organ Blood Flow responses to equipotent concentrations of halothane and sevoflurane during spontaneous ventilation in the rat. The MAC values for halothane and sevoflurane were determined. Cardiac output and Organ Blood Flows were measured using radiolab
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Haemodynamic and Organ Blood Flow responses to sevoflurane during spontaneous ventilation in the rat: a dose-response study.
Canadian journal of anaesthesia = Journal canadien d'anesthesie, 1992Co-Authors: Mark W. Crawford, Jerrold Lerman, Victor Saldivia, M A Pilato, Hector Orrego, F. J. CarmichaelAbstract:To determine the systemic haemodynamic and Organ Blood Flow responses to the administration of sevoflurane during spontaneous ventilation, heart rate, cardiac index, mean arterial pressure, arterial Blood gases, and Blood Flows to the brain, spinal cord, heart, kidneys and splanchnic Organs were measured awake (control values) and after 30 min of anaesthesia with 0.5,1.0,1.2 or 1.5 MAC sevoflurane in rats. Cardiac output and Organ Blood Flows were measured using radiolabelled microspheres. The MAC (mean ± SEM) of sevoflurane was found to be 2.30 ± 0.05%. At each concentration, haemodynamic variables were similar to awake values with the exception of a 12% reduction in mean arterial pressure at 1.5 MAC (P < 0.01). Arterial PCO2 increased in a dose-related fashion. Cerebral and spinal cord Blood Flows increased at 1.2 and 1.5 MAC whereas coronary and renal Blood Flows did not change significantly. Portal tributary Blood Flow and preportal vascular resistance were unaffected. Hepatic arterial Flow increased by 63% at 1.5 MAC (P < 0.05) but total liver Blood Flow remained unchanged compared with awake values. In conclusion, the administration of sevoflurane during spontaneous ventilation produces a high degree of cardiovascular stability and maintains Blood Flow to major Organs in the rat.
Clive N. May - One of the best experts on this subject based on the ideXlab platform.
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The effect of normal saline resuscitation on vital Organ Blood Flow in septic sheep
Intensive care medicine, 2006Co-Authors: Li Wan, Rinaldo Bellomo, Clive N. MayAbstract:Objective To study the effect of resuscitation with normal saline on vital Organ Blood Flow and renal function in sepsis.
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norepinephrine and vital Organ Blood Flow during experimental hyperdynamic sepsis
Intensive Care Medicine, 2003Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:To study the effect of norepinephrine (NE) infusion on cerebral, coronary, renal and mesenteric Blood Flow during sepsis. Randomised placebo-controlled animal trial in the animal laboratory of university physiology institute. Seven merino cross-ewes. Chronic implantation of Flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous bolus of E. coli (3×109). After the onset of hyperdynamic sepsis sheep were randomly allocated to either NE (0.4 µg kg−1 min−1) or placebo for 6 h. E. coli induced hypotension, fever, oliguria, tachycardia and tachypnoea. It increased cardiac output and renal, mesenteric and coronary Blood Flows. Sagittal Flow remained unchanged. Compared to placebo NE infusion restored mean arterial Blood pressure and further increased cardiac output. The increases in renal, mesenteric and coronary Blood Flow were unaffected. Sagittal Flow was also unaltered. Compared to placebo NE increased myocardial performance, mean urine output and creatinine clearance at 2 h. We conclude that hyperdynamic sepsis increases Blood Flow to heart, gut and kidney and that NE further increases cardiac output, Blood pressure, myocardial performance, and urine output and creatinine clearance while maintaining regional Blood Flow.
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Vital Organ Blood Flow During Hyperdynamic Sepsis
Chest, 2003Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:Objectives: To develop a nonlethal model of hyperdynamic sepsis, and to measure vital Organ Blood Flows in this setting. Design: Randomized crossover animal study. Setting: Animal laboratory of university-affiliated physiology institute. Subjects: Seven Merino cross sheep. Interventions: Surgical implantation of transit-time Flow probes around sagittal sinus and circumflex coronary, superior mesenteric, and left renal arteries, and of an electromagnetic Flow probe around the ascending aorta. After recovery, randomization to either 6 h of observation under normal conditions (control) or 6 h of observation after the induction of hyperdynamic nonlethal sepsis (sepsis), with each animal crossing over to the other treatment after a 2-week interval. Measurements and main results: Injection of Escherichia coli induced nonlethal hyperdynamic sepsis within 5 to 6 h with hypotension (mean arterial pressure [± SD], 85 ± 7 mm Hg vs 69 ± 8 mm Hg), increased cardiac output (4.0 ± 0.9 L/min vs 7.2 ± 1.2 L/min), tachycardia (60 ± 10 beats/min vs 160 ± 15 beats/min), fever, oliguria, and tachypnea. Compared to control animals, hyperdynamic sepsis increased renal (330 ± 101 mL/min vs 214 ± 75 mL/min), mesenteric (773 ± 370 mL/min vs 516 ± 221 mL/min), and coronary (54 ± 24 mL/min vs 23 ± 10 mL/min) Blood Flow (p Conclusions: Injection of E coli induced hyperdynamic nonlethal sepsis. During such hyperdynamic sepsis, Blood Flow to heart, gut, and kidney was markedly increased; however, Organ dysfunction developed. We speculate that global ischemia may not be the principal mechanism of vital Organ dysfunction in hyperdynamic sepsis.
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norepinephrine and vital Organ Blood Flow
Intensive Care Medicine, 2002Co-Authors: David Di Giantomasso, Clive N. May, Rinaldo BellomoAbstract:Abstract Objective. To test whether norepinephrine (NE) infusion at 0.4 µg kg–1 min–1 adversely affects regional Blood Flow in the normal mammalian circulation. Design and setting. Randomized cross-over experimental animal study in a university-affiliated physiology institute. Subjects. Six merino ewes. Interventions. Staged insertion of transit-time Flow probes around the ascending aorta and circumflex coronary, superior mesenteric and left renal arteries. In conscious animals with chronically embedded Flow probes randomization to either 6 h of placebo (saline) or drug (NE at 0.4 µg kg–1 min–1). Measurements and results. Compared to placebo, NE significantly increased mean arterial pressure (84.4 vs. 103.8 mmHg), heart rate (61.0 vs. 74.6 bpm) and cardiac output (3.76 vs. 4.78 l/min). These changes were associated with an increase in coronary Blood Flow (24.2 vs. 37.4 ml/min) and renal Blood Flow (215.2 vs. 282.0 ml/min) but no change in mesenteric Blood Flow. The increase in renal and coronary Blood Flow was associated with an increase in regional conductance (regional vasodilatation), while mesenteric conductance fell (mesenteric vasoconstriction). Urine output (91±17 vs. 491±360 ml/h) and creatinine clearance (61±18 vs. 89±12 ml/min) increased during NE infusion. Conclusions. NE infusion does not induce vital Organ ischaemia in the normal mammalian circulation. Furthermore, it results in a significant increase in coronary and renal Blood Flow with a concomitant improvement in urine output and creatinine clearance.
Torkjel Tveita - One of the best experts on this subject based on the ideXlab platform.
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Effects of Rewarming with Extracorporeal Membrane Oxygenation to Restore Oxygen Transport and Organ Blood Flow After Hypothermic Cardiac Arrest in a Porcine Model.
2021Co-Authors: Jan Harald Nilsen, Sergei Valkov, Rizwan Mohyuddin, Torstein Schanche, Gary C. Sieck, Torvind Naesheim, Brage Haaheim, Timofei V Kondratiev, Torkjel TveitaAbstract:Abstract Background: We recently documented that cardiopulmonary resuscitation (CPR) for hypothermic cardiac arrest maintains cardiac output (CO) and mean arterial pressure (MAP) to the same reduced level during normothermia (38°C) vs. hypothermia (27°C). Furthermore, continuous CPR at 27°C maintains CO and MAP throughout a 3-h period, and provides O2 delivery to support aerobic metabolism. The aim of the present study was to investigate the effects of extracorporeal membrane oxygenation (ECMO) rewarming to restore O2 delivery and Organ Blood Flow. Methods: Eight male pigs were anesthetized and immersion cooled to 27°C. After induction of hypothermic cardiac arrest, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed with ECMO. Organ Blood Flow was measured using microspheres. Results: After cooling with spontaneous circulation to 27°C, MAP and CO were initially reduced to 66 and 44% of baseline, respectively. By 15 min after the onset of CPR, there was a further reduction in MAP and CO to 42 and 25% of baseline, respectively, which remained unchanged throughout the rest of 3-h CPR. During CPR, O2 delivery and O2 uptake (V̇O2) fell to critical low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. Rewarming with ECMO restored MAP, CO, O2 delivery, and Blood Flow to the heart and to parts of the brain, whereas Flow to kidneys, stomach, liver and spleen remained significantly reduced. Conclusions: CPR for 3-h at 27°C with sustained lower levels of CO and MAP and maintained aerobic metabolism sufficient to support O2 delivery. Rewarming with ECMO restores Blood Flow to the heart and brain, and creates a “shockable” cardiac rhythm. Thus, like continuous CPR, ECMO rewarming plays a crucial role in “the chain of survival” when resuscitating victims of hypothermic cardiac arrest.
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study of the effects of 3 h of continuous cardiopulmonary resuscitation at 27 c on global oxygen transport and Organ Blood Flow
Frontiers in Physiology, 2020Co-Authors: Jan Harald Nilsen, Sergei Valkov, Rizwan Mohyuddin, Torstein Schanche, Timofei Kondratiev, Gary C. Sieck, Torvind Naesheim, Torkjel TveitaAbstract:Aims Complete restitution of neurologic function after 6 h of pre-hospital resuscitation and in-hospital rewarming has been reported in accidental hypothermia patients with cardiac arrest (CA). However, the level of restitution of circulatory function during long-lasting hypothermic cardiopulmonary resuscitation (CPR) remains largely unknown. We compared the effects of CPR in replacing spontaneous circulation during 3 h at 27°C vs. 45 min at normothermia by determining hemodynamics, global oxygen transport (DO2), oxygen uptake (VO2), and Organ Blood Flow. Methods Anesthetized pigs (n = 7) were immersion cooled to CA at 27°C. Predetermined variables were compared: (1) Before cooling, during cooling to 27°C with spontaneous circulation, after CA and subsequent continuous CPR (n = 7), vs. (2) before CA and during 45 min CPR in normothermic pigs (n = 4). Results When compared to corresponding values during spontaneous circulation at 38°C: (1) After 15 min of CPR at 27°C, cardiac output (CO) was reduced by 74%, mean arterial pressure (MAP) by 63%, DO2 by 47%, but Organ Blood Flow was unaltered. Continuous CPR for 3 h maintained these variables largely unaltered except for significant reduction in Blood Flow to the heart and brain after 3 h, to the kidneys after 1 h, to the liver after 2 h, and to the stomach and small intestine after 3 h. (2) After normothermic CPR for 15 min, CO was reduced by 71%, MAP by 54%, and DO2 by 63%. After 45 min, hemodynamic function had deteriorated significantly, Organ Blood Flow was undetectable, serum lactate increased by a factor of 12, and mixed venous O2 content was reduced to 18%. Conclusion The level to which CPR can replace CO and MAP during spontaneous circulation at normothermia was not affected by reduction in core temperature in our setting. Compared to spontaneous circulation at normothermia, 3 h of continuous resuscitation at 27°C provided limited but sufficient O2 delivery to maintain aerobic metabolism. This fundamental new knowledge is important in that it encourages early and continuous CPR in accidental hypothermia victims during evacuation and transport.
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Organ Blood Flow and o2 transport during hypothermia 27 c and rewarming in a pig model
Experimental Physiology, 2019Co-Authors: Sergei Valkov, Rizwan Mohyuddin, Jan Harald Nilsen, Torstein Schanche, Timofei Kondratiev, Gary C. Sieck, Torkjel TveitaAbstract:New findings What is the central question of this study? Absence of hypothermia-induced cardiac arrest is a strong predictor for a favourable outcome after rewarming. Nevertheless, detailed knowledge of preferences in Organ Blood Flow during rewarming with spontaneous circulation is largely unknown. What is the main finding and its importance? In a porcine model of accidental hypothermia, we find, despite a significantly reduced cardiac output during rewarming, normal Blood Flow and O2 supply in vital Organs owing to patency of adequate physiological compensatory responses. In critical care medicine, active rewarming must aim at supporting the spontaneous circulation and maintaining spontaneous autonomous vascular control. Abstract The absence of hypothermia-induced cardiac arrest is one of the strongest predictors for a favourable outcome after rewarming from accidental hypothermia. We studied temperature-dependent changes in Organ Blood Flow and O2 delivery ( D O 2 ) in a porcine model with spontaneous circulation during 3 h of hypothermia at 27°C followed by rewarming. Anaesthetized pigs (n = 16, weighing 20-29 kg) were randomly assigned to one of two groups: (i) hypothermia/rewarming (n = 10), immersion cooled to 27°C and maintained for 3 h before being rewarmed by pleural lavage; and (ii) time-matched normothermic (38°C) control animals (n = 6), immersed for 6.5 h, the last 2 h with pleural lavage. Regional Blood Flow was measured using a neutron-labelled microsphere technique. Simultaneous measurements of D O 2 and O2 consumption ( V O 2 ) were made. During hypothermia, there was a reduction in Organ Blood Flow, V O 2 and D O 2 . After rewarming, there was a 40% reduction in stroke volume and cardiac output, causing a global reduction in D O 2 ; nevertheless, Blood Flow to the brain, heart, stomach and small intestine returned to prehypothermic values. Blood Flow in the liver and kidneys was significantly reduced. Cerebral D O 2 and V O 2 returned to control values. After hypothermia and rewarming there is a significant lowering of D O 2 owing to heart failure. However, compensatory mechanisms preserve O2 transport, Blood Flow and V O 2 in most Organs. Nevertheless, these results indicate that hypothermia-induced heart failure requires therapeutic intervention.
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Organ Blood Flow and O2 transport during hypothermia (27°C) and rewarming in a pig model.
Experimental physiology, 2018Co-Authors: Sergei Valkov, Rizwan Mohyuddin, Jan Harald Nilsen, Torstein Schanche, Timofei Kondratiev, Gary C. Sieck, Torkjel TveitaAbstract:New findings What is the central question of this study? Absence of hypothermia-induced cardiac arrest is a strong predictor for a favourable outcome after rewarming. Nevertheless, detailed knowledge of preferences in Organ Blood Flow during rewarming with spontaneous circulation is largely unknown. What is the main finding and its importance? In a porcine model of accidental hypothermia, we find, despite a significantly reduced cardiac output during rewarming, normal Blood Flow and O2 supply in vital Organs owing to patency of adequate physiological compensatory responses. In critical care medicine, active rewarming must aim at supporting the spontaneous circulation and maintaining spontaneous autonomous vascular control. Abstract The absence of hypothermia-induced cardiac arrest is one of the strongest predictors for a favourable outcome after rewarming from accidental hypothermia. We studied temperature-dependent changes in Organ Blood Flow and O2 delivery ( D O 2 ) in a porcine model with spontaneous circulation during 3 h of hypothermia at 27°C followed by rewarming. Anaesthetized pigs (n = 16, weighing 20-29 kg) were randomly assigned to one of two groups: (i) hypothermia/rewarming (n = 10), immersion cooled to 27°C and maintained for 3 h before being rewarmed by pleural lavage; and (ii) time-matched normothermic (38°C) control animals (n = 6), immersed for 6.5 h, the last 2 h with pleural lavage. Regional Blood Flow was measured using a neutron-labelled microsphere technique. Simultaneous measurements of D O 2 and O2 consumption ( V O 2 ) were made. During hypothermia, there was a reduction in Organ Blood Flow, V O 2 and D O 2 . After rewarming, there was a 40% reduction in stroke volume and cardiac output, causing a global reduction in D O 2 ; nevertheless, Blood Flow to the brain, heart, stomach and small intestine returned to prehypothermic values. Blood Flow in the liver and kidneys was significantly reduced. Cerebral D O 2 and V O 2 returned to control values. After hypothermia and rewarming there is a significant lowering of D O 2 owing to heart failure. However, compensatory mechanisms preserve O2 transport, Blood Flow and V O 2 in most Organs. Nevertheless, these results indicate that hypothermia-induced heart failure requires therapeutic intervention.
