Effect of Mild Hypothermia on the Coagulation-Fibrinolysis System and Physiological Anticoagulants after Cardiopulmonary Resuscitation in a Porcine Model
et al. (2013) Effect of Mild Hypothermia on the Coagulation-Fibrinolysis System and Physiological
Anticoagulants after Cardiopulmonary Resuscitation in a Porcine Model. PLoS ONE 8(6): e67476. doi:10.1371/journal.pone.0067476
Effect of Mild Hypothermia on the Coagulation- Fibrinolysis System and Physiological Anticoagulants after Cardiopulmonary Resuscitation in a Porcine Model
Sheng Li 0
Ping Gong 0
Ming-Yue Zhang 0
Hong Zhao 0
Zi-Ren Tang 0
Rong Hua 0
Xue Mei 0
Juan Cui 0
Hugo ten Cate, Maastricht University Medical Center, The Netherlands
0 1 Department of Emergency, First Hospital affiliated to Dalian Medical University , Dalian, Liaoning , People's Republic of China, 2 Department of Emergency, Beijing Chaoyang Hospital, Capital Medical University , Beijing , People's Republic of China
The aim of this study was to evaluate the effect of mild hypothermia on the coagulation-fibrinolysis system and physiological anticoagulants after cardiopulmonary resuscitation (CPR). A total of 20 male Wuzhishan miniature pigs underwent 8 min of untreated ventricular fibrillation and CPR. Of these, 16 were successfully resuscitated and were randomized into the mild hypothermia group (MH, n = 8) or the control normothermia group (CN, n = 8). Mild hypothermia (33uC) was induced intravascularly, and this temperature was maintained for 12 h before pigs were actively rewarmed. The CN group received normothermic post-cardiac arrest (CA) care for 72 h. Four animals were in the sham operation group (SO). Blood samples were taken at baseline, and 0.5, 6, 12, 24, and 72 h after ROSC. Whole-body mild hypothermia impaired blood coagulation during cooling, but attenuated blood coagulation impairment at 72 h after ROSC. Mild hypothermia also increased serum levels of physiological anticoagulants, such as PRO C and AT-III during cooling and after rewarming, decreased EPCR and TFPI levels during cooling but not after rewarming, and inhibited fibrinolysis and platelet activation during cooling and after rewarming. Finally, mild hypothermia did not affect coagulation-fibrinolysis, physiological anticoagulants, or platelet activation during rewarming. Thus, our findings indicate that mild hypothermia exerted an anticoagulant effect during cooling, which may have inhibitory effects on microthrombus formation. Furthermore, mild hypothermia inhibited fibrinolysis and platelet activation during cooling and attenuated blood coagulation impairment after rewarming. Slow rewarming had no obvious adverse effects on blood coagulation.
Funding: This study was supported by the National Natural Science Foundation of China (No. 30972863, http://184.108.40.206/portal/proj_search.asp). The
funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Despite new therapeutic approaches in recent decades, the
prognosis after CA and cardiopulmonary resuscitation (CPR) has
remained poor. In a recent study of 24,132 patients in the United
Kingdom who were admitted to critical care units after CA, the
inhospital mortality rate was 71% . Reperfusion failure,
ischemiareperfusion injury, and cerebral injury may be responsible for an
overwhelming systemic inflammatory response associated with
elevated plasma cytokines, presence of circulating endotoxin,
leukocyte dysregulation, and adrenal dysfunction, reflecting a
picture similar to that observed in severe sepsis [2,3]. Current
research has shown that CPR and return of spontaneous
circulation (ROSC) are associated with marked activation of
blood coagulation without adequate concomitant activation of
endogenous fibrinolysis [4,5]. Methods to attenuate this
dysfunction could have great clinical importance.
Recently, two independent groups have shown that induction of
mild hypothermia in patients after CA is associated with reduced
mortality and a better neurological outcome compared with
normothermic controls [6,7]. Based on these findings, 2010
American Heart Association Guidelines for Cardiopulmonary
Resuscitation and Emergency Cardiovascular Care recommend
that unconscious, adult patients successfully resuscitated from an
out-of-hospital ventricular fibrillation (VF) CA should be cooled to
3234uC for 1224 h. Though previous researchers have found
that blood coagulation disorders are one of the complications of
mild hypothermia therapy and hyperfibrinolysis is common in
outof-hospital CA [8,9,10], there are limited data available in the
literature regarding the effect of mild hypothermia on the
coagulation-fibrinolysis system and physiological anticoagulants
from the time of CPR to 72 h after ROSC. This was the subject of
Materials and Methods
This study was conducted with the approval of the Animal Care
and Use Committee at Chaoyang Hospital, affiliated with Capital
Medical University, China. The protocol was approved by the
Committee on the Ethics of Animal Experiments of Capital
Medical University (Permit Number: 2010-D-013). All animals
were treated in compliance with the National Research Councils
1996 Guide for the Care and Use of Laboratory Animals.
Wuzhishan miniature pigs were selected for this study. After 20
generations of inbreeding, Wuzhishan miniature pigs have the
highest inbreeding coefficient (more than 0.965), more stable
heredity, and less variability between individual animals, as well as
a closer resemblance to human beings . Thus, they are
considered an appropriate experimental model for CA.
A total of 24 Wuzhishan miniature pigs (1213 months old,
27.533 kg) were fasted overnight but had free access to water.
Anesthesia was induced by intramuscular injection of midazolam
(0.5 mg/kg), followed by ear vein injection of propofol (1.0 mg/
kg). Anesthesia and analgesia were maintained by continuous
infusion of sodium pentobarbital (8 mg/kg/h) and fentanyl (5 mg/
kg/h). The average period of anesthesia was 7262 h. A cuffed
6.5mm endotracheal tube was advanced into the trachea. All animals
were mechanically ventilated with a volume-controlled ventilator
(Servo 900c; Siemens, Munich, Germany) with a tidal volume of
15 mL/kg, a ventilation rate of 12 to 20 breaths/min, a constant
fraction of inspired oxygen of 0.21, and an inspiration/expiration
ratio of 1:2 with a positive end-expiratory pressure of 5 cmH2O.
End-tidal PCO2 (ETCO2) was monitored with an in-line infrared
capnograph (CO2SMOplus monitor, Respironics Inc., Pittsburgh,
Pennsylvania, USA). Respiratory frequency was adjusted to
maintain ETCO2 between 35 and 40 mmHg before inducing
CA and after ROSC. Room temperature was maintained at 26uC.
An angiographic catheter (7-Fr, Edwards Life Sciences, Irvine,
California, USA) was inserted from the left femoral artery into the
aortic arch for obtaining arterial blood samples and for measuring
mean arterial pressure (MAP). Radiographic examination was
used to verify placement of the angiographic catheter. The
electrocardiogram and hemodynamic parameters such as heart
rate (HR) and arterial pressure were electronically monitored
(M1165; Hewlett-Packard Company, Palo Alto, California, USA)
and recorded throughout the study. A 5-Fr catheter was inserted
into the right external jugular vein to place an electrode catheter,
and ventricular fibrillation (VF) was induced by a programmed
electrical stimulation instrument (GY-600A; Kaifeng, Henan,
China). All catheters were calibrated before use, and their
positions were verified by the presence of typical pressure waves.
After preparation and catheter insertion, animals were allowed
to equilibrate for 30 min to achieve a stable resting level, and
baseline values were obtained. In 20 of the 24 pigs, VF was
induced and was confirmed by the VF wave in the ECG and by
sharply decreased blood pressure. When VF occurred, mechanical
ventilation ceased. After 8 min of untreated VF, CPR was
manually performed according to the 2010 American Heart
Association Guidelines for Cardiopulmonary Resuscitation and
Emergency Cardiovascular Care. After delivery of 30
compressions, animals received two breaths using a bag respirator with
room air. After 2 min of CPR (compression-to-ventilation ratio of
30:2), defibrillation (Smart Biphasic, Philips Healthcare,
Eindhoven, Netherlands) was attempted using 150 J for the first attempt.
If VF still persisted, another 2-min of CPR was resumed, followed
by the first bolus of epinephrine (30 mg/kg). Additional doses of
epinephrine were administered, if needed, every 3 min until
ROSC was achieved. If the first defibrillation attempt was
unsuccessful, 200 J were used for the second and all subsequent
attempts. ROSC was defined as .10 min of systolic blood
pressure maintained continuously .50 mmHg. Four animals with
no ROSC after four attempts of defibrillation were pronounced
dead. The remaining 16 successfully resuscitated pigs were
randomly treated with either endovascular mild hypothermic
(mild hypothermia group, MH, n = 8) or normothermic (control
normothermia group, CN, n = 8) post-CA care. Another four
miniature pigs were in the sham operation group (SO) with no VF,
CPR, or mild hypothermia treatment. Randomization was
performed using the envelope method. Controlled mild
hypothermia was induced and maintained using an intravascular cooling
device (CoolGard 3000, Alsius, Irvine, California, USA). Cooling
(1.0uC/h) was initiated immediately after ROSC in the MH
group. The heat-exchange catheter (IcyTM, Alsius, Irvine,
California, USA) was placed into the vena cava via the right
external jugular vein, and cooled normal saline was infused
through a closed loop system into two heat-exchange balloons
located near the distal end of the catheter. The temperature of the
normal saline was adjusted automatically by the CoolGard 3000
according to feedback to the external pump/refrigerant device
from a microthermister attached to a Foley bladder catheter.
Target temperature was set at 33uC and maintained for 12 h,
followed by active rewarming to 38uC (0.5uC/h). Temperatures
were measured via bladder-temperature probes and were recorded
throughout the study. Animals underwent an intensive care period
until 72 h after ROSC, and mechanical ventilation was resumed
with the same settings as were used before CA. Ringers lactate
and saline 0.9% or glucose were infused intravenously at a rate of
10 mL/kg/h to maintain fluid balance. At 72 h after ROSC,
animals were sacrificed with an intravenous injection of propofol
(60 mg) followed by an intravenous injection of potassium chloride
(10 mL of 10 mol/L). Researchers were blinded to treatment until
data collection was complete.
Blood samples were collected via arterial catheter at 6 time
points: baseline and 0.5, 6, 12, 24, and 72 h after ROSC. The
initial 5 mL of each blood sample was discarded. Blood samples
(5 mL) were collected in 0.109 M trisodium citrate tubes (9:1 vol/
vol) and centrifuged immediately for 10 min at 3000 r/min. The
plasma was used to measure prothrombin time (PT) and activated
partial thromboplastin time (APTT) using reagents from Dade
Behring Inc. (Westwood, Massachusetts, USA) and an automated
blood coagulation analyzer (Sysmex CA-1500, Kobe, Japan). PT
and APTT were measured at 37uC. Measurements were
performed in triplicate, then averaged. The remaining plasma
was stored at 280uC until analysis. Samples were analyzed by
enzyme-linked immunosorbent assay (ELISA) using porcine
ELISA kits (Groundwork Biotechnology Diagnosticate Ltd, San
Diego, California, USA) for: antithrombin III (AT-III), protein C
(PRO C), protein S (PRO S), thrombomodulin (TM), endothelial
cell protein C receptor (EPCR), tissue factor pathway inhibitor
(TFPI), tissue type plasminogen activator (tPA), plasminogen
activator inhibitor 1 (PAI-1), and granule membrane protein a
Statistical analysis was performed with SPSS 17.0 software
(SPSS Inc., Chicago, Illinois, USA). All data were shown as mean
6 standard deviation (SD), except for ROSC and survival
numbers. Body weight, bladder temperature, mean arterial
pressure, heart rate, duration of CPR and number of defibrillation
attempts were compared between groups using a one-way analysis
of variance (ANOVA). Coagulation, physiological anticoagulants,
serum fibrinolysis and platelet activation parameters were
compared between groups using a repeated- measures ANOVA.
The Bonferroni test was used for multiple comparisons. A two
sided p,0.05 was considered statistically significant.
Baseline Characteristics, Resuscitation Data, and Bladder
At baseline, there were no significant group differences in body
weight (BW), bladder temperature (BT), mean arterial pressure, or
heart rate (p.0.05, Table 1). Duration of CPR (3.261.1 vs.
3.361.2 min, p.0.05) and number of defibrillation attempts
(1.560.5 vs.1.760.6, p.0.05) were also similar between CN and
In the CN group, BT values were maintained at 36.538.8uC
during the observation period. In the MH group, BT values
decreased to the target temperature (33uC) within 24 h, remained
at this temperature (3360.2uC) for 12 h, and then gradually
increased over 12 h (Figure 1), consistent with the landmark study
by Bernard .
The CN group had lower PT levels from 6 to 12 h and lower
APTT levels from 0.5 to 12 h after ROSC, compared to the SO
group (all p,0.01). PT returned to SO levels at 24 and 72 h, while
APTT levels were elevated at 24 and 72 h, compared to the SO
group (all p,0.01). Compared to the CN group, the MH group
showed increased PT (Figure 2A) and APTT (Figure 2B) from 0.5
to 12 h after ROSC (all p,0.01). PT levels were similar at 24 h,
but decreased at 72 h compared to the CN group, and APTT
levels were decreased at 24 and 72 h compared to the CN group
As shown in Figure 3, compared to the SO group, the CN
group had lower serum levels of PRO C at 6 h (p,0.01) and
higher serum levels of AT-III, PRO S, TM, EPCR and TFPI at 6
and 12 h after ROSC (all p,0.01). At 24 h, the CN group had
decreased AT-III, PRO S, and PRO C (all p,0.05) and increased
TM and EPCR (all p,0.05). At 72 h, the CN group had
decreased AT-III, PRO S and TFPI (all p,0.05) and increased
Compared to the CN group, at 6 h after ROSC, the MH group
had decreased serum levels of AT-III, PRO S, TM, EPCR and
TFPI (all p,0.01). At 12 h, the MH group had decreased TM,
EPCR and TFPI and increased AT-III (all p,0.01). At 24 h, the
MH group had increased AT-III, PRO S and TFPI (all p,0.01)
and decreased TM and EPCR (all p,0.01). At 72 h, the MH
group had increased AT-III, PRO S and TFPI (all p,0.01) and
decreased TM (p,0.01). PRO C was consistently increased from 6
to 72 h after ROSC (all p,0.05).
CN (n = 8)
MH (n = 8)
SO (n = 4)
MAP (mmHg) HR (bpm)
Values are mean 6 SD. BW, body weight; BT, bladder temperature; MAP, mean
arterial pressure; HR, heart rate; CN, control normothermia group; MH, mild
hypothermia group; SO, sham operation group.
Figure 3. Serum physiological anticoagulant levels. (A) AT-III, Antithrombin III; (B) PRO C, protein C; (C) PRO S, protein S; (D) TM,
thrombomodulin; (E) EPCR, endothelial cell protein C receptor; (F) TFPI, tissue factor pathway inhibitor; CN, control normothermia group; MH, mild
hypothermia group; SO, sham operation group. &p,0.05 CN group vs. SO group. &&p,0.01 CN group vs. SO group. *p,0.05 MH group vs. CN group.
**p,0.01 MH group vs. CN group.
Serum Fibrinolysis and Platelet Activation Parameters
As shown in Figure 4, compared to the SO group, the CN
group had higher serum levels of tPA, PAI-1, and GMP-140 from
6 to 72 h after ROSC (all p,0.01). Compared to the CN group,
the MH group had decreases in these parameters from 6 to 72 h
after ROSC (except for PAI-1 at 72 h) (all p,0.05).
The key findings of this study were: (1) whole-body mild
hypothermia attenuated the impairment in blood coagulation at
72 after ROSC, despite contributing to impairment of blood
coagulation during cooling; (2) whole-body mild hypothermia
increased serum levels of physiological anticoagulants, such as
PRO C and AT-III, and decreased EPCR and TFPI during
cooling; (3) whole-body mild hypothermia inhibited fibrinolysis
and platelet activation during cooling and after rewarming; and (4)
slow rewarming had no obvious adverse effects on
coagulationfibrinolysis, physiological anticoagulants, or platelet activation
CA and resuscitation are accompanied by marked activation of
blood coagulation, which can induce microthrombus and blockage
of microcirculation in the brain or myocardium, leading to
ischemia-reperfusion injury [4,5,12,13,14]. In the well-established
pig CA model induced by VF [11,15,16,17,18,19,20,21,22,23], we
found that whole-body mild hypothermia prolonged APTT and
PT, consistent with a previous report . In addition, some
studies have demonstrated that mild hypothermia resulted in mild
platelet dysfunction, partial inhibition of the coagulation cascade,
and decreased platelet count [9,25,26,27]. Thus, the findings from
our laboratory and from others suggest that mild hypothermia
exerts an anticoagulant effect. Suppressing coagulation may
provide protection by decreasing cerebral or myocardial
microthrombus formation [24,27]. In addition, increasing evidence has
shown a crosstalk between inflammation and thrombosis
[28,29,30] and a concurrent activation of the inflammatory
system and the coagulation cascade during CPR and after ROSC
Figure 4. Serum fibrinolysis and platelet activation parameter levels. (A) tPA, tissue type plasminogen activator; (B) PAI-1, plasminogen
activator inhibitor 1; (C) GMP-140, granule membrane protein a; CN, control normothermia group; MH, mild hypothermia group; SO, sham operation
group. &&p,0.01 CN group vs. SO group. *p,0.05 MH group vs. CN group. **p,0.01 MH group vs. CN group.
 . Thus, the effects of mild hypothermia on coagulation
are also associated with inhibition of inflammation [15,33,34].
Our data showed that mild hypothermia significantly increased
serum levels of physiological anticoagulants, such as PRO C
during cooling and AT-III at 12 h after ROSC, which could
explain its anticoagulant effects. There are three major
anticoagulant mechanisms in the coagulation cascade: 1) Antithrombin
system: AT-III is a key inhibitor of the coagulation system, which
directly inhibits activated thrombin through formation of the
thrombin-antithrombin complex. 2) Protein C system: PRO C is
activated on the cell surface when thrombin binds to
thrombomodulin (TM). The conversion to activated protein C (APC) is
augmented by EPCR, which is present on endothelial cells. PRO
S, as the cofactor of PRO C, could significantly enhance PRO C
function. 3) TFPI: TFPI is a Kunitz-type inhibitor that directly
inhibits tissue factor/factor VIIa complex in the presence of factor
Xa, as the specific inhibitor of the extrinsic coagulation pathway.
However, our study also demonstrated that mild hypothermia
decreased serum levels of AT-III and PRO S at 0.5 and 6 h after
ROSC and TM, EPCR and TFPI during cooling. TM and EPCR
are markers of endothelial injury [14,35], thus decreased levels of
these substances during cooling suggests that mild hypothermia
may protect endothelial cells, consistent with the study by
Kazanskaya . We speculate that protection against endothelial
cell damage by mild hypothermia might contribute to the
increased levels of PRO C observed during cooling. In addition,
the pattern of effects of mild hypothermia on physiological
anticoagulants might indicate a new equilibrium that prevents
dysfunctional anticoagulation during cooling.
The coagulation cascade is now recognized to be a series of
proteolytic events that are primarily localized to the surface of
activated platelets. Once platelets become activated by exposure to
activated endothelium, they release mediators such as GMP-140
(namely P-selectin) [37,38], which promotes microvesicle
formation and platelet adherence, enabling the cascading proteolytic
cleavages of zymogens to active enzymes and culminating in
thrombin generation. In this study, we observed increased
GMP140 in normothermic pigs resuscitated from CA, consistent with
the clinical study by Bottiger , whereas mild hypothermia
attenuated this increase in GMP-140. These data suggest that mild
hypothermia may exert its anticoagulant effects by inhibiting
In addition to coagulation/anticoagulation,
fibrinolysis/antifibrinolysis systems are activated in patients who undergo CPR
[4,10,40]. In the present study, normothermic pigs resuscitated
from CA had increased levels of tissue plasminogen activator
(tPA), which catalyzes the conversion of plasminogen to plasmin
(responsible for clot breakdown) and of plasminogen activator
inhibitor-1 (PAI-1), which is the principal inhibitor of tPA. Bottiger
et al.  observed only slight to moderate activation of
endogenous fibrinolysis, which could not adequately balance the
marked activation of blood coagulation. They concluded that
these changes may contribute to reperfusion disorders, such as the
cerebral no-reflow phenomenon, by inducing fibrin deposition
and formation of microthrombi . However, our results showed
that mild hypothermia significantly decreased tPA and PAI-1
levels, indicating inhibition of activated fibrinolysis/antifibrinolysis
in addition to blood coagulation, consistent with the study by
Interestingly, we found that mild hypothermia attenuated blood
coagulation impairment despite increases in AT-III, PRO C, PRO
S and TFPI at 72 h after ROSC, which might partially explain its
beneficial effects. We speculate that the reduction in blood
coagulation impairment after treatment by mild hypothermia
might be associated with other positive effects of mild
hypothermia, whose mechanisms need to be further investigated. Another
interesting finding was that slow rewarming had no obvious
adverse effects on coagulation-fibrinolysis, physiological
anticoagulants, or platelet activation. At the end of rewarming (24 h after
ROSC), compared to the CN group, the MH group showed
similar PT, decreased APTT, tPA, PAI-1 and GMP-140, and
increased AT-III, PRO S and TFPI, despite decreased TM and
The current study had some limitations. First, catheter insertion
may itself affect coagulation conditions within animals. However,
we designed the SO group and strictly standardized the
experimental protocol to minimize confounding factors. Second,
the experiment was performed on apparently healthy pigs,
whereas most individuals with CA have underlying pathologic
findings. Third, this study did not include blood gas analysis to
assess acid base status. Finally, high tidal volume (15 ml/kg),
which was used in this study to maintain normocapnia, may
induce lung injury with subsequent inflammation. However, all
animals were ventilated using the same procedure, regardless of
their group assignment.
In conclusion, mild hypothermia exerted an anticoagulant effect
during cooling, which may have inhibitory effects on
microthrombus formation. Furthermore, mild hypothermia inhibited
fibrinolysis and platelet activation during cooling and attenuated blood
coagulation impairment after rewarming. Slow rewarming had no
obvious adverse effects on blood coagulation.
The authors would like to thank Xian-Fei Ji, Shuo Wang, Jun-Yuan Wu,
Zhi-Yu Su and Hong-Tao Zhang for their excellent technical assistance. In
addition, they also thank Hui Chen for her excellent statistical assistance.
Conceived and designed the experiments: PG MYZ CSL. Performed the
experiments: PG MYZ HZ ZRT XM RH JC CSL. Analyzed the data:
MYZ. Contributed reagents/materials/analysis tools: MYZ HZ PG ZRT
XM RH JC CSL. Wrote the paper: PG MYZ.
1. Nolan JP , Laver SR , Welch CA , Harrison DA , Gupta V , et al. ( 2007 ) Outcome following admission to UK intensive care units after cardiac arrest: a secondary analysis of the ICNARC Case Mix Programme Database . Anaesthesia 62 : 1207 - 1216 .
2. Adrie C , Adib-Conquy M , Laurent I , Monchi M , Vinsonneau C , et al. ( 2002 ) Successful cardiopulmonary resuscitation after cardiac arrest as a ''sepsis-like'' syndrome . Circulation 106 : 562 - 568 .
3. Hekimian G , Baugnon T , Thuong M , Monchi M , Dabbane H , et al. ( 2004 ) Cortisol levels and adrenal reserve after successful cardiac arrest resuscitation . Shock 22 : 116 - 119 .
4. Bottiger BW , Motsch J , Bohrer H , Boker T , Aulmann M , et al. ( 1995 ) Activation of blood coagulation after cardiac arrest is not balanced adequately by activation of endogenous fibrinolysis . Circulation 92 : 2572 - 2578 .
5. Gando S , Kameue T , Nanzaki S , Nakanishi Y ( 1997 ) Massive fibrin formation with consecutive impairment of fibrinolysis in patients with out-of-hospital cardiac arrest . Thromb Haemost 77 : 278 - 282 .
6. Bernard SA , Gray TW , Buist MD , Jones BM , Silvester W , et al. ( 2002 ) Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia . N Engl J Med 346 : 557 - 563 .
7. Hypothermia after Cardiac Arrest Study Group ( 2002 ) Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest . N Engl J Med 346 : 549 - 556 .
8. Schmied H , Kurz A , Sessler DI , Kozek S , Reiter A ( 1996 ) Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty . Lancet 347 : 289 - 292 .
9. Valeri CR , Feingold H , Cassidy G , Ragno G , Khuri S , et al. ( 1987 ) Hypothermia-induced reversible platelet dysfunction . Ann Surg 205 : 175 - 181 .
10. Schochl H , Cadamuro J , Seidl S , Franz A , Solomon C , et al. ( 2013 ) Hyperfibrinolysis is common in out-of-hospital cardiac arrest: Results from a prospective observational thromboelastometry study . Resuscitation 84 : 454 - 459 .
11. Gong P , Li CS , Hua R , Zhao H , Tang ZR , et al. ( 2012 ) Mild hypothermia attenuates mitochondrial oxidative stress by protecting respiratory enzymes and upregulating MnSOD in a pig model of cardiac arrest . PLoS One 7 : e35313 .
12. Bottiger BW , Martin E ( 2001 ) Thrombolytic therapy during cardiopulmonary resuscitation and the role of coagulation activation after cardiac arrest . Curr Opin Crit Care 7 : 176 - 183 .
13. Fischer M , Bottiger BW , Popov-Cenic S , Hossmann KA ( 1996 ) Thrombolysis using plasminogen activator and heparin reduces cerebral no-reflow after resuscitation from cardiac arrest: an experimental study in the cat . Intensive Care Med 22 : 1214 - 1223 .
14. Adrie C , Monchi M , Laurent I , Um S , Yan SB , et al. ( 2005 ) Coagulopathy after successful cardiopulmonary resuscitation following cardiac arrest: implication of the protein C anticoagulant pathway . J Am Coll Cardiol 46 : 21 - 28 .
15. Zhao H , Li CS , Gong P , Tang ZR , Hua R , et al. ( 2012 ) Molecular mechanisms of therapeutic hypothermia on neurological function in a swine model of cardiopulmonary resuscitation . Resuscitation 83 : 913 - 920 .
16. Hua R , Li CS , Gong P , Tang ZR , Mei X , et al. ( 2012 ) Cerebrospinal fluid biochemistry reflects effects of therapeutic hypothermia after cardiac arrest in a porcine model . Am J Emerg Med 30 : 1420 - 1428 .
17. Tang ZR , Li CS , Zhao H , Gong P , Zhang MY , et al ( 2013 ) Effects of Hypothermia Treatment on Brain Injury Assessed by MRI after Cardiopulmonary Resuscitation in the Pig . Am J Emerg Med 31 : 86 - 93 .
18. Wang S , Li CS , Ji XF , Yang L , Su ZY , et al. ( 2010 ) Effect of continuous compressions and 30:2 cardiopulmonary resuscitation on global ventilation/ perfusion values during resuscitation in a porcine model . Crit Care Med 38 : 2024 - 2030 .
19. Ji XF , Shuo W , Yang L , Li CS ( 2012 ) Impaired beta-adrenergic receptor signalling in post-resuscitation myocardial dysfunction . Resuscitation 83 : 640 - 644 .
20. Ji XF , Li CS , Wang S , Yang L , Cong LH ( 2010 ) Comparison of the efficacy of nifekalant and amiodarone in a porcine model of cardiac arrest . Resuscitation 81 : 1031 - 1036 .
21. Ji XF , Yang L , Zhang MY , Li CS , Wang S , et al. ( 2011 ) Shen-fu injection attenuates postresuscitation myocardial dysfunction in a porcine model of cardiac arrest . Shock 35 : 530 - 536 .
22. Wu JY , Li CS , Liu ZX , Wu CJ , Zhang GC ( 2009 ) A comparison of 2 types of chest compressions in a porcine model of cardiac arrest . Am J Emerg Med 27 : 823 - 829 .
23. Su ZY , Li CS , Han Y , Yin X , Guo M ( 2011 ) Evaluation of cerebral metabolism by (1)H-magnetic resonance spectroscopy for 4 degrees C saline-induced therapeutic hypothermia in pig model of cardiac arrest . Am J Emerg Med 29 : 913 - 921 .
24. Hu CL , Wen J , Liao XX , Li X , Li YJ , et al. ( 2011 ) Effects of therapeutic hypothermia on coagulopathy and microcirculation after cardiopulmonary resuscitation in rabbits . Am J Emerg Med 29 : 1103 - 1110 .
25. Watts DD , Trask A , Soeken K , Perdue P , Dols S , et al. ( 1998 ) Hypothermic coagulopathy in trauma: effect of varying levels of hypothermia on enzyme speed, platelet function, and fibrinolytic activity . J Trauma 44 : 846 - 854 .
26. Valeri CR , MacGregor H , Cassidy G , Tinney R , Pompei F ( 1995 ) Effects of temperature on bleeding time and clotting time in normal male and female volunteers . Crit Care Med 23 : 698 - 704 .
27. Polderman KH ( 2009 ) Mechanisms of action, physiological effects, and complications of hypothermia . Crit Care Med 37 : S186 - 202 .
28. Esmon CT ( 2008 ) Crosstalk between inflammation and thrombosis . Maturitas 61 : 122 - 131 .
29. Esmon CT ( 2003 ) Coagulation and inflammation . J Endotoxin Res 9 : 192 - 198 .
30. van der Spuy WJ , Pretorius E ( 2012 ) Interrelation between inflammation, thrombosis, and neuroprotection in cerebral ischemia . Rev Neurosci 23 : 269 - 278 .
31. Levi M , Keller TT , van Gorp E , ten Cate H ( 2003 ) Infection and inflammation and the coagulation system . Cardiovasc Res 60 : 26 - 39 .
32. Adrie C , Laurent I , Monchi M , Cariou A , Dhainaou JF , et al. ( 2004 ) Postresuscitation disease after cardiac arrest: a sepsis-like syndrome? Curr Opin Crit Care 10 : 208 - 212 .
33. Meybohm P , Gruenewald M , Albrecht M , Zacharowski KD , Lucius R , et al. ( 2009 ) Hypothermia and postconditioning after cardiopulmonary resuscitation reduce cardiac dysfunction by modulating inflammation, apoptosis and remodeling . PLoS One 4 : e7588 .
34. Meybohm P , Gruenewald M , Zacharowski KD , Albrecht M , Lucius R , et al. ( 2010 ) Mild hypothermia alone or in combination with anesthetic postconditioning reduces expression of inflammatory cytokines in the cerebral cortex of pigs after cardiopulmonary resuscitation . Crit Care 14 : R21 .
35. Nozza S , Pogliaghi M , Chiappetta S , Spagnuolo V , Fontana G , et al. ( 2012 ) Levels of soluble endothelial protein C receptor are associated with CD4+ changes in Maraviroc-treated HIV-infected patients . PLoS One 7 : e37032 .
36. Kazanskaya GM , Volkov AM , Karas'kov AM , Lomivorotov VN , Shun'kin AV ( 1999 ) Experimental studies on the endothelium ultrastructure of heart capillaries under moderate (28-30 degrees) and deep (22-24 degrees) hypothermia without perfusion . Microvasc Res 58 : 250 - 267 .
37. Green D ( 2006 ) Coagulation cascade . Hemodial Int 10 Suppl 2 : S2 - 4 .
38. Andre P ( 2004 ) P-selectin in haemostasis . Br J Haematol 126 : 298 - 306 .
39. Bottiger BW , Motsch J , Braun V , Martin E , Kirschfink M ( 2002 ) Marked activation of complement and leukocytes and an increase in the concentrations of soluble endothelial adhesion molecules during cardiopulmonary resuscitation and early reperfusion after cardiac arrest in humans . Crit Care Med 30 : 2473 - 2480 .
40. Neumar RW , Nolan JP , Adrie C , Aibiki M , Berg RA , et al. ( 2008 ) Post-cardiac arrest syndrome: epidemiology, pathophysiology, treatment, and prognostication. A consensus statement from the International Liaison Committee on Resuscitation (American Heart Association, Australian and New Zealand Council on Resuscitation, European Resuscitation Council, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Council of Asia, and the Resuscitation Council of Southern Africa); the American Heart Association Emergency Cardiovascular Care Committee; the Council on Cardiovascular Surgery and Anesthesia; the Council on Cardiopulmonary, Perioperative, and Critical Care; the Council on Clinical Cardiology; and the Stroke Council . Circulation 118 : 2452 - 2483 .
41. Staikou C , Paraskeva A , Drakos E , Anastassopoulou I , Papaioannou E , et al. ( 2011 ) Impact of graded hypothermia on coagulation and fibrinolysis . J Surg Res 167 : 125 - 130 .