Brain Death Patients Research Articles

Fasciculations in brain death

Brain death is the colloquial name for human death determined by tests showing irreversible cessation of the clinical functions of the brain. Spontaneous and reflex movements have been described in brain death. The aim of this report is to describe a brain-dead patient with unusual motor movements. The patient was followed and her motor movements were videotaped. We report the presence of extensive and long-lasting fasciculations in a patient who fulfilled the criteria for brain death. We describe and show on videotape a brain-dead patient with rare motor movements. We suggest that fasciculations outlined in this study has to be accepted as motor symptoms in brain death patients.

Imminent brain death and brain death are not the same: reply to Verheijde and Rady

Dear Editor, Verheijde and Rady [1] suggest, referring to our recent article in Intensive Care Medicine [2], that imminent brain death (IBD) expands the pool of brain death (BD) for heart-beating organ donation (HBD). This statement is incorrect. As we stated, IBD “should not be considered equivalent to brain (stem) death and that the designation of a patient with IBD represents no more than a certain risk estimate” to become BD. However, BD patients can be included in the pool of IBD patients following our strict definition, which states that only patients who are “…with irreversible catastrophic brain damage of a known origin…” are considered to be in a state of IBD. Verheijde and Rady mention that IBD patients are not suitable for organ donation, as IBD patients may die several hours to days following withdrawal of mechanical ventilation. However, IBD patients may deteriorate, despite the most aggressive treatment of pathologically raised intracranial pressure (ICP), into a state of BD. Most patients fulfilling the criteria for IBD will die within an hour after withdrawal of mechanical ventilation and when a patient is determined BD, the view of Verheijde and Rady is no longer tenable. IBD is, as clearly described by us in our article, a risk estimate and not a decision tool to withdraw life support. Verheijde and Rady worry about the harmful and painful procedures after the determination of IBD but that ignores the severity of the injury and IBD patients are deeply comatose, many irreversibly so. Because of its importance, we stated in our original article: “treating-limiting decisions remain the responsibility of the clinician who should base his decisions as much as possible on evidence-based risk estimates, taking opinions of relatives and autonomy of patient into account”. This is in clear contradiction with the second, third, and fourth statement made by Verheijde and Rady. One of the goals of IBD was to provide the clinician with a tool for early recognition of a potential organ donor (POD). Even initial contact with an organ donation procurement agency does not absolve the clinician of the duty to treat the patient. The decision to pursue aggressive medical or neurosurgical management and the decision to consider organ donation are totally independent of each other and always have been. The letter by Verheijde and Rady, however, is also a jeremiad against all that is wrong about BD determination. The last statement “some clinicians reject scientific evidence disproving the very concept of BD as equivalent to death” is odd and factually incorrect. It will be hard to find a physician closely involved with BD determination and organ donation who does not think these PODs are dead. Finally, we should correct Verheijde and Rady’s historical inaccuracy claiming that Beecher coined the term “brain death”. It was Schwab, who presented his triad for certifying brain death at the 16th annual meeting of the American Electroencephalography Society in 1962 [3].

Selective 4 Vessels Angiography in Brain Death: A Retrospective Study

In Canada, ancillary tests, such as selective four vessels angiography (S4VA), are sometimes necessary for brain death (BD) diagnosis when the clinical exam cannot be completed or confounding factors are present. Recent Canadian guidelines assert that brain death is supported by the absence of arterial blood flow at the surface of the brain and that venous return should not be considered. However, neuropathologic and angiographic studies have suggested that arteries might still be patent in BD patients. Current clinical practices in BD diagnosis following S4VA need to be better understood. We conducted a retrospective study of all S4VA performed for the determination of BD in a level 1 NeuroTrauma centre from 2003 to 2007. The objective of the study was to describe the prevalence of intracranial arterial, capillary (parenchymogram) and venous opacification in our study population. All tests were reviewed independently by two neuroradiologists. Disagreements were resolved by consensus. Thirty two patients were declared BD following S4VA during the study period. Nine of these patients (28%) presented some proximal opacification of intracranial arteries (95% CI 15-45%). As opposed, none had a cerebral capillary and deep venous drainage opacification (95% CI 0-10%). The absence of cerebral deep venous drainage or parenchymogram might represent a better objective marker of cerebral circulatory arrest for brain death diagnosis when the use of S4VA is required. These findings open the path for further research in enhancing our interpretation of angiographic studies for brain death diagnosis.

37. Causes of brain death patients in emergency neurology

37. Causes of brain death patients in emergency neurology

Functional Improvement Between Brain Death Declaration and Organ Harvesting

Introduction The quality of harvested organs is crucial for graft survival and for posttransplant evolution. This study sought to investigate the evolution of the functional status of brain death (BD) patients during the period between declaration and organ harvesting (BD duration). Materials and Methods The study included all BD patients who underwent organ harvesting between January 2006 and June 2009. We compared the functional status regarding hemodynamics, respiration, kidney and liver function, coagulation, water, electrolytes, and acid–base balance evaluated at the moment of BD declaration (P1) and just before organ harvesting (P2). The results of the comparison were expressed as improvement, stable, or aggravation. We calculated mean values of the functional parameters in P1 and P2 and the statistical significance of the differences. Results Twelve BD patients were included in the study. The time interval between P1 and P2 was 16.08 ± 8.54 hours (range, 6–32). The number of patients with vasopressor support was 9/12 at P1 and 0/12 at P2, oxygenation disturbances 1/12 in P1 and 0/12 in P2, renal dysfunction 9/12 in P1 and 2/12 in P2, liver dysfunction 7/12 in P1 and 1/12 in P2, coagulopathy 4/12 in P1 and 0/12 in P2, hypernatremia 8/12 in P1 and 3/12 in P2, and metabolic acidosis 9/12 in P1 and 1/12 in P2. The overall assessment showed improvement in all patients. The most statistically significant improvement was registered in the cardiovascular, respiratory, renal, liver, and acid–base status ( P < .05). Conclusion With early, aggressive, protocolized donor management, functional improvement may be achieved during BD duration.

Bispectral Index Scale alterations in brain death patients

Brain death (BD) is defined as the total and irreversible loss of brain function, including the brain stem. According to current Greek guidelines, low BD diagnosis is determined only by clinical criteria, thus electroencephalogram (EEG), cerebral angiography or transcranial Doppler are not considered mandatory for BD confirmation. The Bispectral Index Scale (BIS) is a multifactorial parameter derived from the EEG, which allows monitoring of the hypnotic component of anaesthesia. Furthermore, it has been reported that there is a good correlation between BIS and neurological status in unsedated coma patients. In addition, it has been recently suggested that BIS is associated with the Glasgow Coma Score (GCS) and could serve as a good predictor tool for the outcome after head trauma. Moreover it has been reported that BIS can be used in the early detection of BD. The aim of the present study was to record the BIS alterations in BD patients.

The Organ Donation Rates in the Neurosurgical Field: Preliminary Study in a Single Institute

,Background: In this study, we analyzed the brain death patients and the donation rates in our neurosurgical field and we discuss the factors that may be important for maximizing these rates by review of literatures.

The bispectral index, a useful adjunct for the timely diagnosis of brain death in the comatose trauma patient

Background The bispectral index (BIS) is a processed electroencephalographic value (awake = 100, isoelectric = 0). The relationship of BIS and brain death (BD) is assessed. Methods BIS was evaluated in GCS 3 head-injured patients with BD (no brain function including apnea) or near BD (no apnea or negative ancillary test [cerebral perfusion and electroencephalogram]). Results In 27 patients, there were 37 BD evaluations (apnea assessment or ancillary test). BD was confirmed in 62% (n = 23). However, 38% (n = 14) showed near BD. BD BIS is 3 ± 5 and near BD BIS is 36 ± 31 ( P = .002). In the 23 BD patients, BIS was <20 for 7 hours ± 6 hours before a BD evaluation was performed. Of 14 near BD evaluations, 9 (64%) had BIS ≥20. BIS <20 for predicting BD had a sensitivity of 100% (23/23), a positive predictive value of 84% (23/28), and a negative predictive value of 100% (9/9). Conclusions Distinguishing brain death and near brain death in severely comatose trauma patients is complex. By indicating the likelihood of brain death, BIS is an adjunct for efficient evaluation.

Diagnosing Brain Death by CT Perfusion and Multislice CT Angiography

Although the diagnosis of brain death (BD) is usually based on clinical criteria, in sedated patients, ancillary techniques are needed. This study was designed to assess the accuracy of cerebral multislice computed tomographic angiography (CTA) and CT perfusion (CTP) in diagnosing BD. Prospective observational study in 27 BD patients. All patients were diagnosed as BD based on clinical and electroencephalogram findings. After BD diagnosis, CTP was performed followed by 64-detector multislice CTA from the aortic arch to the vertex. Images were reconstructed from 0.5 mm sections. In 24 patients, a lack of cerebral blood flow (CBF) was detected by CTP, and CTA revealed luminal narrowing of the internal carotid artery in the neck and absence of anterior and posterior intracranial circulation (sensitivity 89%). CTA detected CBF exclusively in extracranial portions of the internal carotid and vertebral arteries. Two patients with anoxic brain injury and decompressive craniectomy showed CBF in the CTA such that the CTP results were considered false negatives, given BD had been confirmed by clinical and EEG findings, along with evoked potentials. In one clinically BD patient, in whom an alpha rhythm was detected in the electroencephalogram, CBF was only observed in the intracranial internal carotid with no posterior circulation noted. This patient was therefore considered exclusively brain stem dead. The radiological protocol used shows a high sensitivity and excellent specificity for detecting the cerebral circulatory arrest that accompanies BD. As a rapid, non-invasive, and widely available technique it is a promising alternative to conventional 4-vessel angiography.

Limitations of computed tomographic angiography in the diagnosis of brain death

To evaluate the accuracy of cerebral computed tomographic angiography (CT-a) for the diagnosis of brain death (BD). Prospective observational study in intensive care units. Twenty-one clinically BD patients enrolled over 12 months. All clinically BD patients were evaluated by electroencephalography (EEG) and CT-a after exclusion of hypothermia and drug intoxication. Data collected included: demographic characteristics, cause of BD, delay between in-hospital admission and BD diagnosis and between EEG and CT-a, occurrence of cardiac arrest, administration of vasoactive agents, results of EEG and CT-a. We evaluated the sensitivity of EEG and CT-a and their agreement. Groups were compared according to BD diagnosis by EEG and CT-a (E+C+), or only by EEG (E+C(-)). Statistical analysis were performed by Mann-Whitney test and Fisher's exact test. BD was confirmed by EEG in all cases (sensitivity 100%) whereas only 11 patients of 21 had no cerebral perfusion during CT-a (sensitivity 52.4%). No agreement was documented between EEG and CT-a for the diagnosis of BD (kappa = 0). Patients' characteristics did not differ between E+C+ and E+C(-) groups. In the E+C(-) group arterial opacification was observed in 100% of patients, but opacification of the internal cerebral veins was achieved in only 30%. In clinically BD patients with no electroencephalographic activity CT-a documents opacification of the intracerebral vessels in a significant percentage of the cases. Therefore CT-a cannot be recommended as a means of BD diagnosis.

Extracranial Carotid and Vertebral Artery Ultrasonography: Resistive Indices for Diagnosing Cerebral Brain Death

Introduction —Transcranial Doppler (TCD) has been used to document blood flow indicative of patients who are clinically brain dead. Limitations of TCD include signal loss in the absence of an adequate acoustic window, or extensive craniotomies that interfere with TCD insonation. Additionally, when compared with duplex ultrasonography of extracranial carotid and vertebral arteries, TCD is more technically difficult to master, with limited availability in many institutions. Objective —We sought to evaluate the use of carotid and vertebral artery ultrasound resistive indices in patients with clinically diagnosed brain death. Methods —Standard carotid and vertebral duplex ultrasound protocol was used to evaluate extracranial arteries in 2 groups: I: 8 control subjects, mean age of 49 years, without evidence of carotid or vertebral atherosclerosis, and II: 8 patients, mean age of 48 years, diagnosed with brain death confirmed by electroencephalography. All patients had insignificant (&lt; 50% stenosis) carotid and vertebral atherosclerosis. T-test was used to compare common carotid, internal carotid (ICA), external carotid, and vertebral (VERT) artery resistive indices between Groups I and II. Results —Common carotid (0.74 ± 0.04 vs. 0.88 ± 0.08), ICA (0.60 ± 0.06 vs. 1.00 ± 0.00), and VERT (0.61 ± 0.05 vs. 1.00 ± 0.00) artery resistive indices were significantly lower in normal subjects than in brain death patients ( p &lt; 0.05). Both ICA and VERT waveforms in brain death patients demonstrated the oscillatory, “to-and-fro,” pattern already established with TCD. Conclusion —Extracranial ICA and VERT waveforms in patients diagnosed with clinical brain death have the same resistive indices and waveform patterns that have been used to identify brain death intracranially with TCD. Because standard duplex ultrasonography is the most commonly used noninvasive modality for cerebrovascular evaluation, we believe this method may be easier to understand and more readily available for the initial diagnosis of cerebral brain death.

Undulating toe movements in brain death*

For many years, death implied immobility. Nevertheless, there are anecdotal reports of spontaneous or reflex movements (SRMs) in patients with Brain death (BD). The presence of some movements can preclude the diagnosis of BD, and consequently, the possibility of organ donation for transplantation. McNair and Meador [(1992), Mov Dord7: 345-347] described the presence of undulating toe flexion movements (UTF) in BD patients. UTF consists in a sequential brief plantar flexion of the toes. Our aim was to determine the frequency, characteristics and predisposing factors of UTF movements in a prospective multicenter cohort study of patients with BD. Patients with confirmed diagnosis of BD were assessed to evaluate the presence of UTF using a standardized protocol. All patients had a routine laboratory evaluation, CT scan of the head, and EEG. Demographic, clinical, hemodynamic and blood gas concentration factors were analyzed. amongst 107 BD patients who fulfilled the AAN requirements, 47 patients (44%) had abnormal movements. UTF was observed in 25 (23%) being the most common movement (53%). Early evaluation (OR 4.3, CI95% 1.5-11.9) was a predictor of UTF in a multivariate regression model. The somato-sensory evoked potential (SSEPs) as well as brainstem auditory evoked potentials (BAEPs) did not elicit a cortical response in studied patients with UTF. This spinal reflex is probably integrated in the L5 and S1 segments of the spinal cord. Abnormal movements are common in BD, being present in more than 40% of individuals. UTF was the most common spinal reflex. In our sample, early evaluation was a predictor of UTF. Health care professionals, especially those involved in organ procurement for transplantation, must be aware of this sign. The presence of this motor phenomenon does not preclude the diagnosis of BD.

Noradrenaline Use in the Human Donor and Relationship with Load-Independent Right Ventricular Contractility

Experimental and clinical studies suggest that brain death (BD)-associated cardiac dysfunction is related to the neurohormonal storm and subsequent exposure to intravenous catecholamines. We aimed to describe the relationship between empirical noradrenaline treatment and donor heart function, described for the first time with load-independent indices of right ventricular contractility. Twenty-seven BD patients were divided in three groups based on noradrenaline at time of offer, started by the donor hospital: group 1=no noradrenaline (n=11); group 2=low dose (n=8); group 3=high dose (n=8). After protocol-guided optimization by our retrieval team using a Swan-Ganz catheter, pressure-volume data were obtained from the right ventricle. Ten patients undergoing coronary revascularization served as controls. Twenty hearts were transplanted, seven of them as heart and lung blocks. Right ventricular end-systolic elastance (E(es)) was lower in BD donors compared with controls (mean 0.28 vs. 0.46 mm Hg/mL, P< or =0.01). There was no difference in terms of Swan-Ganz derived data between the BD subgroups, but E(es) was lower in groups 2 and 3 (P=0.04). Eight patients died within a year (four from graft failure), and they had a donor heart E(es) significantly lower than that of survivors (mean 0.20 vs. 0.33 mm Hg/mL, P=0.01). Hearts from BD donors have subclinical right ventricular impairment in contractility. E(es), a load-independent measure of contractile function, seems to be inversely correlated with empirical use of noradrenaline in the donor and with recipient survival at 1 year. This has implications for refining donor selection and management.

LIVER TRANSPLANTATION USING LIVERS FROM SEPTUAGENARIAN AND OCTOGENARIAN DONORS: AN UNDERUSED STRATEGY TO REDUCE MORTALITY ON THE WAITING LIST.

P100 Aims: Mortality on liver transplantation (LTx) waiting list is increasing dramatically, approaching 20-30% worldwide. The use of “expanded” older donors (>60yo) has become an accepted practice to try enlarging the donor pool. The use of very old donors (>70yo) remains scarce, due to possible underreporting of these donors by donor centers and reluctance to use these very old livers given the risk of poor outcome. We report the outcome of LTx using septuagenarian and octogenarian donors and explore the possible reasons for the underuse of this large potential donor pool. Methods: Between 05/2001 and 01/2004, 7 livers were procured from very old donors (70, 75, 78, 79, 81, 82, 82yo, mean=78.1yo) and found transplantable; 6 were female and 1 male. Cause of death was intracranial bleeding (ICB) (5) and trauma (2). Of note, 6 of 7 donors originated from the same center who follows the policy of routinely contacting the Tx center for all brain-death patients before making final assessment as to their suitability for donation (Spanish-like-system). Results: 7 patients {HCC (5), cryptogenic cirrhosis (1), postethyl (1); 3 females, 3 males; mean age 62 (54-69)} were successfully Tx. In a 7th patient, LTx was aborted due to the perioperative discovery of extra-hepatic malignancy (HCC). Mean cold and warm ischemia times were 8.5hrs (5h49-13h35) and 55.2’ (40-78), respectively. Graft function was immediate in all cases and peak transaminase was low: 784U/L (105-1489). Mean hospital stay was 24.5 days (14-29). Of the 6 LTx, 1 patient with a functioning graft died 2 months postTx (ICB). The other 5 are well. Patient and graft survival is 84%. Conclusions: ICB and brain-death is an important cause of mortality >70yo but this age category currently represents a very small percentage of the donors used for LTx (4%) probably due to a) underreporting by donor teams who erroneously believe that these very old patients are not suitable donors, and b) underuse by recipient teams who fear that these livers may not work. Extremely advanced age is not per se a contra-indication to liver donation and successful LTx. Information to donor teams and routine referral of all brain-death patients to Tx centers is pivotal to allow maximal use of this large donor pool that could substantially reduce the mortality on LTx waiting lists.

Dying in the intensive care unit: collaborative multicenter study about forgoing life-sustaining treatment in Argentine pediatric intensive care units.

Describe modes of death and factors involved in decision-making together with life support limitation (LSL) procedures. Prospective, descriptive, longitudinal, and noninterventional study. Sixteen pediatric intensive care units in Argentina. Every patient who died during a 1-yr period was included. Age, sex, length of stay (LOS), primary and admission diagnosis, underlying chronic disease (CD), postoperative condition (PO). Deaths were classified in four groups: a) failed cardiopulmonary resuscitation (CPR); b) do-not-resuscitate (DNR) status; c) withholding or withdrawing life-sustaining treatment (WH/WD); and d) brain death (BD). Justifications were classified as a) imminent death; b) poor long-term prognosis; c) poor quality of life; and d) family request. Data were collected from medical records and interviews with the attending physicians. Descriptive statistics were performed. Differences among groups were analyzed through contingency tables and analysis of variance when required. Relative risks and confidence intervals of variables potentially related to LSL were analyzed, and logistic regression was performed. There were 6358 admissions and 457 deaths. CPR was performed in 52%, DNR in 16%, WH/WD in 20%, and BD in 11% of dead patients. BD patients were older, LOS and CD prevalence were higher in the WH/WD group. Inotropic drugs were the most frequently limited treatment in 110 patients (55%), CPR in 72 (35.6%), and mechanical ventilation in 63 (31%). Imminent death was the most frequently reported justification for LSL. CD and more staff were associated with a higher probability of LSL. Most of the patients in Argentina underwent CPR before their death. We have a high proportion of patients with CD (65%) and low BD diagnosis. PO condition decreased LSL probability in chronically ill patients. Do-not-resuscitate orders and withholding new treatments were the most common LSL. Active withdrawal was exceptional. The Ethics Committee was consulted in 5% of the LSL population.

Brain death diagnosis in misleading conditions.

The necessity of defining brain death (BD) arose from technological development in medical science. The definition of this concept had practical consequences and opened the way to organ donation from BD patients. Nowadays, the imbalance between the number of organs available for transplantation and the size of the demand is becoming critical. In most laboratories, a BD diagnosis is made according to precise criteria and in a well-defined process. BD diagnosis should be improved, not only to assure the safety and to preserve the human dignity of the patient, but also in order to increase the rate of organ donation. By analysing some epidemiological parameters in BD diagnosis and organ donation, it appears that BD diagnoses can be made more often and more rapidly if one has a reliable, accurate, and safe confirmatory test, especially under misleading conditions (hypothermia, drugs, metabolic disturbances). In our experience, the use of multimodality evoked potentials (MEPs) to confirm a BD diagnosis has many advantages: MEPs can be rapidly performed at the patient's bedside, assess the brain stem as well as the cerebral cortex, and are innocuous for the patient. Moreover, their insensitivity to the aforementioned misleading factors is sufficient to distinguish BD from clinical and EEG states that mimic BD. They give an immediate diagnosis, and no delay is required in BD confirmation if there is sufficient cause to account for BD. MEPs are a safe, accurate, and reliable tool for confirming a BD diagnosis, and their use can improve the organ donation rate while preserving the safety of the patient.

Brain death in ICUs and associated nursing care challenges concerning patients and families.

In order to document the incidence and causes of brain death (BD) and the frequency of organ donation (OD) in a Swedish University Hospital, a retrospective review of deaths in a neurosurgical department and in the general intensive care units (ICUs), was carried out for the period 1988-1994. BD diagnosis was established in 197 (10.6%) of all deaths (n = 1843). The hospital records of all BD patients were examined in detail following a specific study plan. The majority of the BD patients (89%) were acute admissions to hospital, and among them 81 were transferred between hospitals often over a long distance. Among the BD patients the total number of OD was 65 (33%). The most common diagnosis leading to BD was spontaneous intracerebral bleeding and traumatic head injury. The BD diagnosis was established by neurological examination (60%) and by cerebral angiography (40%). Of the BD patients, 50% died within 48 hours in the ICU and the majority of requests for OD (67%) were made to the relatives of these patients. The findings are discussed with focus on the workload and psychological stress of ICU nurses when caring for BD patients and their families; a task which includes taking part in processes concerning BD diagnosis information and OD requests.

Heart rate variability in brain death.

The sensitivity and specificity of heart rate variability (HRV) in the corroboration of brain death diagnosis in patients with acute traumatic intracranial lesions was evaluated in 20 patients with clinical criteria of brain death, nine patients in deep coma (Glasgow scale < 7) and 18 normal controls, all age matched. The electrocardiogram was sampled at 650 Hz and several parameters of HRV were calculated, in both time and frequency domains. The HRV parameters were significantly lower in the brain death group compared with the deep coma group. Linear discriminant analysis between brain death and deep coma patients was performed on a data set made of nine randomly selected patients with clinical criteria of brain death and nine patients in deep coma. Cross-validation was performed on the remaining 11 patients with clinical criteria of brain death. All patients in the data set were correctly classified (sensitivity and specificity of 100%). All patients in the cross-validation set were correctly classified (sensitivity of 100%). Further studies are necessary to evaluate the specificity of the method in the independent set of deep coma patients and in the follow-up of comatose and vegetative patients to identify irreversibility of HRV. Nevertheless, these results suggest that HRV analysis constitutes a fully sensitive and specific method for assessing brain death in potential organ donors with acute traumatic lesions of the brain. This fast, quantitative and bedside method seems very promising for the early confirmation of brain death, which is an important factor for the success of transplantation procedures and could have a high predictive value of brain death in comatose patients with brain injuries without fully diagnostic criteria.

Modalités et causes de 259 décès dans un service de réanimation pédiatrique

Background. — There are few data available from European pediatric intensive care units (PICU) regarding the modes of death and their causes.Population and methods. — Two hundred and fifty nine children, not including neonates, died in the PICU over a 7-year period (1987–1993). Data were obtained from a computerized data base and the retrospective review of medical records by two intensivists. Deaths were classified into three groups according to the terminal event: brain death (BD), unsuccessful resuscitation (UR), do-not-resuscitate order and limitation and/or withdrawal of therapy (LWT).Results. — BD was the most common mode of death (38%); GR accounted for 34% and LWT for 28% of deaths. There was no significant annual vacation in the proportion of BD. UR and LWT. Age and sex were similar in the three groups. The predominant organ system failure involved upon admission was the central nervous system (52%) in the LWT group, and the cardiovascular system (54%) in the UR group. Severe chronic disease (37%) and immunosuppression (19%) were more prevalent in the LWT group than in the BD group. Time from admission to death was longer in the LWT group (median = 119 hours) as compared to the UR group (10 hours) and the BD group (54 hours). Ten percent of the BD patients became organ transplant donors. Sixty-seven per cent of BD patients had medical contraindication for organ donation: parents did not accept organ donation in 61% of potential cases. Thirty deaths (12%) seemed to be avoidable; dehydration from acute infectious gastroenteritis (n = 7) was the most common cause of avoidable death.Conclusions. — The modes of death in our PICU were statistically not different from those seen in two of four North-American PICUs; LWT was less prevalent than in the two other PICUs, but the patient populations were very different (presence of neonates and many cardiovascular surgery patients). Assessment of the severity of illness at admission and of functional outcome in the survivors are mandatory in future studies.

Ｔｒａｎｓｃｒａｎｉａｌ Ｄｏｐｐｌｅｒ法による脳血流動態の研究 特にｐｕｌｓａｔｉｌｉｔｙ ｉｎｄｅｘの意義について

Transcranial Doppler Ultrasonography (TCD) is now commonly used to evaluate the cerebral hemodynamics. However, the blood velocity measured with TCD is not always accurate, because as a rule the direction of the blood flow does not completely coincide with that of the ultrasonic beam. The error in the measurement could be as large as 15%. This could be eliminated by calculating pulsatility index (PI) from the Doppler ultrasonography. This study evaluates the reliability of the PI as an index of cerebral hemodynamics. In total, 164 measurements were made in patients with various cerebrovascular diseases (CVD), including 14 of brain death patients (group B) and 14 of inpending herniation patients (group I). Of CVD, 46 were persistent vegetative state patients (group V), and 43 were in relatively good conditions (group A). Other including 15 of hydrocephalus patients (group H) and 19 of cerebral vasospasm after subarachnoid hemorrhages (group S) were also investigated. Nineteen normal young volunteers (group N) were used as controls. The mean level of PI in group N shows 0.82. PI in group A was increased to 1.04, and in group V, 1.27. Furthermore in the brain death group, the mean level of PI was increased to 3.86, which was statistically significant. It was concluded that measurement of PI was very useful to evaluate the changes of cerebral hemodynamics, and the levels of PI was affected more with the changes in diastolic than in systolic flow velocity.