Haemodynamic management in brain death donors:Influence of aetiology of brain death

BACKGROUND In brain death donors(BDDs),donor management is the key in the complex donation process.Donor management goals,which are standards of care or clinical parameters,have been considered an acceptable barometer of successful donor management.AIM To test the hypothesis that aetiology of brain death could influence haemodynamic management in BDDs.METHODS Haemodynamic data(blood pressure,heart rate,central venous pressure,lactate,urine output,and vasoactive drugs)of BDDs were recorded on intensive care unit(ICU)admission and during the 6-h observation period(Time 1 at the beginning;Time 2 at the end).RESULTS The study population was divided into three groups according to the aetiology of brain death:Stroke(n=71),traumatic brain injury(n=48),and postanoxic encephalopathy(n=19).On ICU admission,BDDs with postanoxic encephalopathy showed the lowest values of systolic and diastolic blood pressure associated with higher values of heart rate and lactate and a higher need of norepinephrine and other vasoactive drugs.At the beginning of the 6-h period(Time 1),BDDs with postanoxic encephalopathy showed higher values of heart rate,lactate,and central venous pressure together with a higher need of other vasoactive drugs.CONCLUSION According to our data,haemodynamic management of BDDs is affected by the aetiology of brain death.BDDs with postanoxic encephalopathy have higher requirements for norepinephrine and other vasoactive drugs.

Evaluation of the updated definition of early allograft dysfunction in donation after brain death and donation after cardiac death liver allografts

BACKGROUND:An updated definition of early allograft dysfunction(EAD) was recently validated in a multicenter study of 300 deceased donor liver transplant recipients.This analysis did not differentiate between donation after brain death(DBD) and donation after cardiac death(DCD) allograft recipients.METHODS:We reviewed our prospectively entered database for all DBD(n=377) and DCD(n=38) liver transplantations between January 1,2006 and October 30,2011.The incidence of EAD as well as its ability to predict graft failure and survival was compared between DBD and DCD groups.RESULTS:EAD was a valid predictor of both graft and patient survival at six months in DBD allograft recipients,but in DCD allograft recipients there was no significant difference in the rate of graft failure in those with EAD(11.5%) compared with those without EAD(16.7%)(P=0.664) or in the rate of death in recipients with EAD(3.8%) compared with those without EAD(8.3%)(P=0.565).The graft failure rate in the first 6 months in those with international normalized ratio ≥1.6 on day 7 who received a DCD allograft was 37.5% compared with 6.7% for those with international normalized ratio <1.6 on day 7(P=0.022).CONCLUSIONS:The recently validated definition of EAD is a valid predictor of patient and graft survival in recipients of DBD allografts.On initial assessment,it does not appear to be a useful predictor of patient and graft survival in recipients of DCD allografts,however a study with a larger sample size of DCD allografts is needed to confirm these findings.The high ALT/AST levels in most recipients of DCD livers as well as the predisposition to biliary complications and early cholestasis make these parameters as poor predictors of graft failure.An alternative definition of EAD that gives greater weight to the INR on day 7 may be more relevant in this population.

Pathological Characteristics of Liver Allografts from Donation after Brain Death Followed by Cardiac Death in Pigs

Donation after brain death followed by circulatory death （DBCD） is a unique practice in China. The aim of this study was to define the pathologic characteristics of DBCD liver allografts in a porcine model. Fifteen male pigs （25-30 kg） were allocated randomly into donation after brain death （DBD）, donation after circulatory death （DCD） and DBCD groups. Brain death was induced by aug- menting intracranial pressure. Circulatory death was induced by withdrawal of life support in DBCD group and by venous injection of 40 mL 10% potassium chloride in DCD group. The donor livers were perfused in situ and kept in cold storage for 4 h. Liver tissue and common bile duct samples were col- lected for hematoxylin and eosin staining, TUNEL testing and electron microscopic examination. Spot necrosis was found in hepatic parenchyma of DBD and DBCD groups, while a large area of necrosis was shown in DCD group. The apoptosis rate of hepatocytes in DBD [（0.56±0.30）%] and DBCD [（0.50 ±0.11）%] groups was much lower than that in DCD group [（3.78±0.33）%] （P〈0.05）. And there was no significant difference between DBD group and DBCD group （P〉0.05））. The structures of bile duct were intact in both DBD and DBCD groups, while the biliary epithelium was totally damaged in DCD group. Under electron microscope, the DBD hepatocytes were characterized by intact cell membrane, well-organized endoplasmic reticulum, mild mitochondria edema and abundant glycogens. Broken cell membrane, mild inflammatory cell infiltration and sinusoidal epithelium edema, as well as reduced glycogen volume, were found in the DBCD hepatocytes. The DCD hepatocytes had more profound cell organelle injury and much less glycogen storage. In conclusion, the preservation injury of DBCD liver allografts is much less severe than that of un-controlled DCD, but more severe than that of DBD liver allografts under electron microscope, which might reflect post-transplant liver function to some extent.

Reuse of liver grafts following the brain death of the initial recipient

AIM: To determine if there is a reasonable prospect of success of a re-use liver transplantation.METHODS: We systematically searched for reports of liver graft re-use using electronic searches of PubMed and Web of Knowledge. We performed hand searches of references lists of articles reporting re-use of grafts.RESULTS: A systematic review of the literature reveals 28 liver transplantations using previously transplanted grafts. First and second recipients ranged in age from 4 to 72 years and 29 to 62 years respectively. Liver disease in the first recipient was varied including 5(18%) patients with fulminant liver failure who died subsequently of cerebral edema. The second transplanta-tion was performed after a median interval of 5 d(one day-13 years). Viral hepatitis was present in 3(11%) of the initial recipients and in 8(29%) of final recipients. Hepatocellular carcinoma was present in 6(21%) of the final recipients. Early survival after the final transplantation was 93%, whereas long-term survival was 78% with a mean follow-up of 23.3(3-120) mo.CONCLUSION: Outcomes of transplantation using previously transplanted grafts in this select population are similar to those seen with conventional grafts.

Benefits of combination of electroencephalography, short latency somatosensory evoked potentials, and transcranial Doppler techniques for confirming brain death

Objective: Optimization of combining electroencephalography (EEG), short latency somatosensory evoked potentials (SLSEP) and transcranial Doppler (TCD) techniques to diagnose brain death. Methods: One hundred and eleven patients (69 males, 42 females) from the major hospitals of Zhejiang Province were examined with portable EEG, SLSEP and TCD devices. Re-examinations occurred ≤12 h later. Results: The first examination revealed that the combination of SLSEP and EEG led to more sensitive diagnoses than the combination of SLSEP and TCD. Re-examination confirmed this and also revealed that the combination of TCD and EEG was the most sensitive. Conclusion: The results show that using multiple techniques to diagnose brain death is superior to using single method, and that the combination of SLSEP and EEG is better than other combinations.

Brain death and organ transplant legislation: analysis of 969 respondents by classroom questionnaire

BACKGROUND: China has the largest potential market for organ transplants in the world, but it has not yet established brain death and organ transplant laws. We aimed to investigate the attitudes and suggestions of doctors, pharmacists, and civil servants concerning brain death, organ transplantation, and their respective legislation. METHODS: A questionnaire with 10 sections and 44 questions was designed and distributed. The effective questionnaire data were then recorded and checked for descriptive analysis. RESULTS: In 1400 questionnaires distributed, 1063 were responded and 969 of them were valid and analyzed. The respondents showed an incomplete understanding of brain death and organ transplantation laws. Seventy-four percent of the respondents recognized and accepted the standard of brain death. They agreed that legislation should be involved in the removal of organs for transplantation, the future use of organs, and insurance and compensation for the donor for possible health risks induced by organ removal. Of the 969 respondents, 92% considered it necessary to have legislation in brain death and organ transplantation, and 61% thought that it is time to legislate. CONCLUSIONS: Legislation for brain death and organ transplantation is urgent and timely in China. The laws must include the respective rights and obligations of patients, close relatives, and medical institutions. Educating the public about brain death and organ transplantation should also be encouraged in a variety of ways.

A Lazarus effect： A case report of Bupropion overdose mimicking brain death

Dear editor, We report a case of a 47-year-old female who presented with a toxic bupropion ingestion leading to cardiac arrest. She initially exhibited a loss of brainstem reflexes in conjunction with burst-suppression pattern on EEG. Burst suppression is an EEG waveform pattern of alternating isoelectric suppressions and high voltage bursts, Our patient ultimately made a full neurologic recovery a few days later. While there are two other cases in the literature of bupropion overdose resulting in EEG burst-suppression and loss of brainstem reflexes, we believe this is the only reported adult case complicated by cardiac arrest.

Nurses’ Recognition in Nursing for Patients and Families about Organ Donation after Brain Death, Care for Family Members and Supports for Nurses

Background: Globally, there a problem of disequilibrium between donation and organ transplantation, this equilibrium is remarkable in Japan. Especially there are few donations from brain death, and researches from the view point of nurses in clinical situation were needed. Purpose: The purpose of this study was to clarify the recognition of nurses in organ transplantation nursing, required care for families of patients, and required support for nurses to promote quality of nurses in organ donation. Methods: We conducted this research within 2 months in 2019 in Western Japan. A researcher conducted a semi-qualitative interview for nurses in organ transplantation nursing about their recognition of nursing, required care for family members, and required support for nurses once. Results: Nurses recognized that some family members who knew patients’ thoughts made decision easily and some who didn’t know had difficulties. Many nurses felt insufficiency for family cares and some confronted ethical problems. Though some nurses felt conflict about their own thoughts or religion, they took care of patients or family members with responsibility. As for care for families, nurses thought practice of care considering families’ feeling, support of decision making, and care for family to live positively after transplantation as required care. About support for nurses, nurses required education of transplantation, increase of staff members, chance to share dilemma, and mental care. Discussion: Nurses recognized the importance of decision making, and felt an insufficiency for family care or dilemmas. To propose high quality of nursing and organ donation or transplantation, education about transplantation including family care, management about resolution of dilemma or mental health may be required.

TRANSCRANIAL DOPPLER CHARACTERISTICS IN PERSISTENT VEGETATIVE STATUS,LOCKED-IN SYNDROME AND BRAIN DEATH

Aim. Comparison of the trascranial Doppler (TCD) characteristics of cerebral circulation in persistent vegetative status (PVS), locked in syndrome and brain death patients. Methods. Using TCD ultrasound to detect the flow velocity and waveform patterns of middle cerebral artery (MCA) and basilar artery (BA) in patients with PVS, locked in syndrome and brain death. Results. The mean velocities of middle cerebral artery (Vmca) and basilar artery (Vba) were 30.0cm/s and 24.3cm/s in PVS patients respectively, which decreased 45.0% and 14.4% in comparing with normal value. For patients with locked in syndrome, Vmca and Vba were 49.7cm/s and 9.8cm/s, which decreased 5.0% and 61.7% than the normal value respectively. These results showed that the decrease of anterior circulation was predominant in PVS, and the decrease of posterior circulation was predominant in locked in syndrome. A unique diastolic reverse flow, short peak systolic wave or undetectable flow signal in middle cerebral artery were predominant in brain death patients, which was completely different from that of either PVS or locked in syndrome. Conclusion. TCD was a valuable tool in distinguishing PVS, locked in syndrome and brain death patients according to the differences in velocities and patterns of anterior and posterior cerebral arteries.

Diffusion Weighted MRI: A Practical and Quick Approach to Evaluate Brain Death

It is significantly important to define brain death with greater precision in terms of timing and accuracy. While in the past determination of brain death is simply based on conventional angiography, now with major technological advances the Diffusion-weighted MRI is a new method sensitive to cerebral ischemia which gives on the molecular level the deeply ischemic nature of the changes. Its value in brain death has been shown in various studies. In our study, we did a comparative overview of diffusion-weighted imaging (DWI) with and magnetic resonance angiography (MRA) considering the contribution of ADC measurements from brain parenchyma, in the patients diagnosed with brain death by clinical criteria. We studied 16 brain deaths in serial studies, in which there is a prominent difference between the white and gray matter ADC values on diffusion MRI. In the postmortem brains, ADC values comparing with the normal brain parenchyma, were reduced 65% in white matter and 42% in gray matter. Also, the patients’ ADC values of gray and white matter were significantly lower than those of irreversible brain-ischemia patients’ in ADC values. In comparison to most of the other studies, in our study population studied is large, in which is a comprehensive study that results consistent with the literature. As a result we propose that in the definition of brain death Diffusion MRI and ADC measurements are reliable to show diffuse ishemic changes of brain parenchyma.

Intestinal microbiota dysbiosis and liver metabolomic changes during brain death

Background Whether a causative link exists between brain death(BD)and intestinal microbiota dysbiosis is unclear,and the distortion in liver metabolism associated with BD requires further exploration.Methods A rat model of BD was constructed and sustained for 9 h(BD group,n=6).The sham group(n=6)underwent the same procedures,but the catheter was inserted into the epidural space without ballooning.Intestinal contents and portal vein plasma were collected for microbiota sequencing and microbial metabolite detection.Liver tissue was resected to investigate metabolic alterations,and the results were compared with those of a sham group.Resultsα-diversity indexes showed that BD did not alter bacterial diversity.Microbiota dysbiosis occurred after 9 h of BD.At the family level,Peptostreptococcaceae and Bacteroidaceae were both decreased in the BD group.At the genus level,Romboutsia,Bacteroides,Erysipelotrichaceae_UCG_004,Faecalibacterium,and Barnesiella were enriched in the sham group,whereas Ruminococcaceae_UCG_007,Lachnospiraceae_ND3007_group,and Papillibacter were enriched in the BD group.Short-chain fatty acids,bile acids,and 132 other microbial metabolites remained unchanged in both the intestinal contents and portal vein plasma of the BD group.BD caused alterations in 65 metabolites in the liver,of which,carbohydrates,amino acids,and organic acids accounted for 64.6%.Additionally,80.0%of the differential metabolites were decreased in the BD group livers.Galactose metabolism was the most significant metabolic pathway in the BD group.Conclusions BD resulted in microbiota dysbiosis in rats;however,this dysbiosis did not alter microbial metabolites.Deterioration in liver metabolic function during extended periods of BD may reflect a continuous worsening in energy deficiency.

Diagnosis of brain death： confirmatory tests after clinical test

Background The brain death confirmation tests occupy a different position in each country＇s diagnostic criteria （or guideline）; the choices of tests are also different.China brain death criteria include clinical judgment and confirmation tests.This study aimed to confirm the preferred confirmatory test and complementary confirmatory tests.Methods We did a clinical brain death determination on deep coma patients,and then divided them into brain death group and non-brain death group.According to the Chinese standards for determining brain death,both the groups accepted confirmatory tests including electroencephalograph （EEG）,somatosensory evoked potentials （SEP）,and transcranial Doppler （TCD）.The sensitivity,specificity,false positive rate,and false negative rate were calculated to evaluate the accuracy of the confirmatory tests.Results Among the 131 cases of patients,103 patients met the clinical criteria of brain death.Respiratory arrest provocation test was performed on 44 cases and 32 cases （73％） successfully completed and confirmed that they have no spontaneous breathing.Of the three confirmation tests,EEG had the highest completion rate （98％） and good sensitivity （83％） and specificity （97％）; TCD had followed completion rate （54％） and not good sensitivity （73％） and specificity （75％）; SEP had the lowest completion rate （49％）,good sensitivity （100％）,and not good specificity （78％）.After the combination of SEP or TCD with EEG,the specificity can increase to 100％.Conclusions The completion rate of respiratory arrest provocation test remains a problem in the clinical diagnosis of brain death.If the test cannot be completed,whether to increase a confirmatory test is debatable.SEP had an ideal sensitivity,and the specificity will reach 100％ after combining with TCD or EEG.When a confirmed test was uncertain,we suggest increasing another confirmatory test.

Protective effects of glycine pretreatment on brain-death donor liver

BACKGROUND: Morphological and functional changes commonly occur in livers of brain-death donors. Preven- tion of liver injury from brain-death will benefit the results of transplantation. This study was conducted to evaluate the protection effects of glycine on the liver of brain-death donor. METHODS: Fourty-two male Wistar rats were randomly divided into brain-death donor (BDD) group (B), glycine pretreatment group with BDD (G), and strychnine pre- treatment group with BDD(S). For these groups, brain death model was established in donor rats and liver trans- plantation was performed subsequently utilizing microsur- gical techniques. After the establishment of the model and during cold rinsing of liver donors or liver reperfusion of recipients, glycine was given at a dose of 0. 6 mmol, 25 μmol and 25 μmol in the group G, and a same dose of gly- cine and strychnine (1000 :1) was prescribed for the group S, but nothing for the group B. Before cold rinsing at 2 and 6 hours after portal vein(PV) reperfusion, blood sam- ples were taken from infrahepatic vena cava (IHVC) to de- termine the levels of alanine aminotransferase (ALT), as- partate aminotransferase (AST), tumor necrosis factor al- pha (TNF-α) and hyaluronic acid (HA). At 6 hours after PV reperfusion, graft samples were fixed for morphological observation and apoptosis of hepatocytes was detected using the TUNEL method. RESULTS: Before liver cold rinsing and at 2 and 6 hours af- ter PV reperfusion, the serum levels of ALT, AST, TNF-α, HA and apoptosis index (AI) in the groups B and S were significantly higher than those in the group G (P <0.05). There was no significant difference between the groups B and S (P>0.05). Electron microscopy showed that Kupffer cells were activated and hepatic cells injured more obvious- ly in the groups B and S than in the group G. CONCLUSION: Glycine pretreatment can improve the via-bility of the liver of the brain-death donor rat.

Carbon monoxide inhalation ameliorates conditions of lung grafts from rat brain death donors

Background Successful lung transplantation has been limited by the scarcity of donors. Brain death （BD） donors are major source of lung transplantation. Whereas BD process induces acute lung injury and aggravates lung ischemia reperfusion injury. Carbon monoxide （CO） inhalation at 50-500 parts per million （ppm） can ameliorate lung injury in several models. We examined in rats whether CO inhalation in BD donor would show favorable effects on lung grafts. Methods Rats were randomly divided into 4 groups. In sham group, donor rats received insertion of a balloon catheter into the cranial cavity, but the balloon was not inflated. In BD-only group, donor rats were ventilated with 40% oxygen after BD confirmation. In BD＋CO250 and BD＋CO500 groups, donor rats inhaled, after BD confirmation, 250 ppm or 500 ppm CO for 120 minutes prior to lung procurement, and orthotopic lung transplantation was performed. The rats were sacrificed 120 minutes after the lung transplantation by exsanguination, and their blood and lung graft samples were obtained. A total of 8 rats fulfilling the criteria were included in each group. Results The inhalation decreased the severity of lung injury in grafts from BD donors checked by histological examination. CO pretreatment reversed the aggravation of PaO2/FiO2 in recipients from BD donors. The CO inhalation down-regulated pro-inflammatory cytokines （TNF-α, IL-6） along with the increase of anti-inflammatory cytokine （IL-10） in recipient serum, and inhibited the activity of myeloperoxidase in grafts tissue. The inhalation significantly decreased cell apoptosis in lung grafts, inhibiting mRNA and protein expression of intercellular adhesion molecule-1 （ICAM-1） and caspase-3 in lung grafts. Further, the inhalation activated phosphorylation of p38 expression and inhibited phosphorylation of anti-extracellular signal-regulated kinase （ERK） expression in lung grafts. The effects of CO at 500 ppm were greater than those at 250 ppm. Conclusions CO exerts potent protective effects on lung grafts from BD donor, exhibiting anti-inflammatory and anti-apoptosis functions by modulating the mitogen-activated protein kinase （MAPK） signal transduction.

A Comparison of Brain Death Criteria between China and the United States

Background： Criteria for determining brain death （BD） vary between China and the United States. We reported the results of an investigation designed to compare procedures to determine BD in two countries. Methods： The latest criteria in the United states were published in 2010. The latest criteria in China were published in 2009. We used these two types of BD criteria to evaluate patients who were considered to be BD. The time, cost, and accuracy of the diagnosis were compared. Results： From January 1, 2012 to October 8, 2013, there were 37 patients which were applied for BD evaluation in the Neurological Intensive Care Unit of Beijing Tiantan Hospital. The cause of coma were known as subarachnoid hemorrhage （18 patients, 48.6%）, intracerebral hemorrhage （8 patients, 21.6%）, cerebral ischemia （9 patients, 24.3%）, brain stem tumor （1 patient, 2.7%）, and intracranial infection （1 patient, 2.7%）. The clinical examinations were done for all of the patients except 1 patient who had low blood pressure. Three patients had hrainstem reflexes that were excluded from BD. Twenty-five patients had apnea tests, and 20 tests were completed that were all positive. Confirmatory tests were completed differently： Transcranial Doppler （30 patients, positive rate 86.7%）, electroencephalogram （25 patients, positive rate 100%）, and somatosensory evoked potential （16 patients, positive rate 100%）. Thirty-three patients were diagnosed BD by criteria of the United States. Only 9 patients were diagnosed BD by Chinese criteria. The use of time and money in the USA criteria was obviously fewer than those in Chinese criteria （P = 0.000）. Conclusion： Compared with BD criteria of the United States, Chinese criteria were stricter, lower positive rate, more cost in money and time, and more reliable by families and doctors.

Outcome of kidney transplantation between controlled cardiac death and brain death donors： a meta-analysis

Background Our goal was to evaluate the outcomes of kidney transplants from controlled cardiac death donors compared with brain death donors by conducting a meta-analysis of cohort studies.Methods The PubMed database and EMBASE were searched from January 1980 to July 2013 to identify studies that met pre-stated inclusion criteria.Reference lists of retrieved articles were also reviewed.Two authors independently extracted information on the designs of the studies,the characteristics of the study participants,and outcome assessments.Results Nine cohort studies involving 84 398 participants were included in this meta-analysis; 3 014 received kidneys from controlled cardiac death donors and 80 684 from brain death donors.Warm ischemia time was significantly longer for the controlled cardiac death donor group.The incidence of delayed graft function was 2.74 times （P 〈0.001） greater in the controlled cardiac death donor group.The results are in favor of the brain death donor group on short-term patient and graft survival while this difference became nonsignificant at mid-term and long term.Sensitivity analysis yielded similar results.No evidence of publication bias was observed.Conclusion This meta-analysis of retrospective cohort studies suggests that the outcome after controlled cardiac death donors is comparable with that obtained using kidneys from brain death donors.

Protective Effects of Salubrinal on Liver Injury in Rat Models of Brain Death

Background： Previous studies have indicated that endoplasmic reticulum stress participates in and mediates liver injury and apoptosis in brain-dead （BD） rats. In this study, we observed the effect ofsalubrinal （Sal, Sigma, USA） on liver cells in BD rats and explored its relevant mechanisms. Methods： Thirty Sprague-Dawley rats were equally randomized into three groups： BD group, Sal group, and DMSO group. The BD models were established by increasing intracranial pressure in a modified, slow, and intermittent way. In the drug groups, Sal was administered I h before the induction of BD. After modeling was completed, the blood and liver samples were harvested. CHOP and Caspase-12 mRNA expression was detected using quantitative polymerase chain reaction. PKR-like ER kinase （PERK）, P-eukaryotic translation initiation factor 2a （elF2a）, elF2a, CHOP and caspase-12 expression was detected using western blotting （WB）. CHOP and caspase-12 distribution and expression in liver tissues were determined using immunohistochemistry （IHC）. Alanine aminotransferase and aspartate aminotransferase level were detected using an automatic biochemical analyzer. Hepatic cell apoptosis was detected using TUNEL. The results were analyzed using Quantity-one v4.62 software （Bio-Rad, USA）. Results： CHOP and caspase-12 expression and PERK, elF2a, and P-elF2a protein expression showed no significant difference between BD group and DMSO group. Compared with BD group, Sal group had a significantly higher P-elF2C level and a lower P-PERK level 2 h and 6 h alter BD （P 〈 0.05）. However, eIF2a expression showed no significant difference （P 〉 0.05）. After the Sal treatment, CHOP and caspase- 12 mRNA expression significantly decreased 4 hatter BD （P 〈 0.05）. WB and IHC indicated that CHOP and caspase- 12 expression also significantly decreased after Sal treatment. Sal was associated with improved liver function and decreased hepatic cell apoptosis. Conclusions： Sal can significantly reduce apoptosis in hepatic cells of BD rats. This protective effect may be achieved via the PERK-elF2a signaling pathway.

Complications associated with the apnea test in the determination of the brain death

Background An apnea test is essential in the clinical determination of brain death. This study was conducted to analyse complications associated with the apnea test in the determination of the brain death. Methods On 93 adult patients in coma in Zhejiang Province of China from January 2003 to December 2006, 179 apnea tests were performed as a part of the determination of brain death. Potential risk conditions and complications were analysed during apnea tests. Results During apnea, serious cardiac arrhythmia did not occur in all patients. Complications occurred in 37 of 179 （21%） apnea tests. Hypotension occurred in 30 patients （17%） and it was observed in 8/94 （9%） tests with baseline value of systolic arterial blood pressure not less than 120 mmHg, and 22/85 （26%） less than 120 mmHg （P 〈0.05）. Severe hypoxaemia occurred in 10 patients （6%） of which 3/138 （2%） tests with baseline value of arterial oxygen pressure not less than 200 mmHg, and 7/41 （17%） less than 200 mmHg （P 〈0.05）. Conclusions This study demonstrated that complications occurred mostly in patients with inadequate baseline systolic arterial blood pressure and preoxygenation. Adequate precautions during the apnea tests may reduce the risk of cardiovascular and oxygenation complication.

Dynamic multivariate multiscale entropy based analysis on brain death diagnosis

The recently introduced multivariate multiscale sample entropy(MMSE)well evaluates the long correlations in multiple channels,so that it can reveal the complexity of multivariate biological signals.The existing MMSE algorithm deals with short time series statically whereas long time series are common for real-time computation in practical use.As a solution,we novelly proposed our dynamic MMSE(DMMSE)as an extension of MMSE.This helps us gain greater insight into the complexity of each section of time series,producing multifaceted and more robust estimates than the standard MMSE.The simulation results illustrated the feasibility and well performance in the brain death diagnosis.

Experimental study on the establishment and maintenance of brain death model with pigs

It remains controversial that after the transplantation of using grafts from brain-dead donors,organs injury and rejection can influence the effects of transplantation.This study sought to explore methods of establishing a stable brain death(BD)model using Bama mini pigs and to maintain the brain-dead state for a comparatively long period to provide a model for investigating changes in brain death.Sixteen anesthetized Bama mini pigs were randomized into a control group(n=5)and a BD group(n=11).Intracranial pressure(ICP)was increased in a modified,slow,and intermittent way to establish BD.Respiration and circulation were sustained during the brain-dead state.Hemodynamic changes were monitored during the experiment.In the BD group,10 pigs met the requirements for brain death and 1 died of cardiopulmonary complications following an increase in ICP.Brain death was maintained for more than 48 hours with artificial life support.During the experiment,the heart rate and blood pressure showed characteristic changes due to increased ICP.Prior to BD being established,a“tic reaction”inevitably occurred.We used an improved method of increasing ICP to establish a stable BD model.The BD state could be maintained for more than 48 hours with effective respiratory and circulatory support.Disappearance of the tic reaction was considered to be one of the verified indexes for BD via encephalic pressure increase.