R. Bohatyrewicz

Computed Tomographic Angiography and Perfusion in the Diagnosis of Brain Death

INTRODUCTION According to Polish brain death (BD) criteria, instrumental confirmatory tests should be used in certain clinical situations, particularly any case for which clinical examinations seem inadequate. Electrophysiological tests are often unavailable. Therefore, cerebral perfusion testing is the method of choice with four-vessel digital subtraction angiography (DSA), the gold standard. Unfortunately, DSA is an expensive and invasive examination that requires an experienced neuroradiologist and the availability of an angiography suite. Recently, multirow computed tomographic devices became available, even in smaller hospitals in Poland. Despite this fact, computed tomographic angiography (CTA) and computed tomographic perfusion (CTP) are not accepted in BD diagnosis protocols in Poland because of limited experience and a lack of widely accepted criteria. In this situation, we started a multicenter trial to determine the accuracy of CTA and CTP to confirm BD. METHODS We examined 24 patients who fulfilled standard clinical BD criteria. We recognized the absence of brain perfusion in CTA examination following the criteria proposed by the French Society of Neuroradiology, namely, the absence of opacification of M4 middle cerebral artery segments (M4-MCA) and of deep cerebral veins. RESULTS In all of our patients, CTA showed absence of opacification of M4 segments and of deep cerebral veins. In addition, three patients had CTA showing weak opacification of A2 segments of the anterior cerebral artery (A2-ACA) and M2 or M3-MCA. Opacification of the basilar artery or of the posterior cerebral arteries was not noted in any case. In all patients, CTP revealed zero values of regional cerebral blood volume and regional cerebral blood flow. Conventional angiography confirmed cerebral circulatory arrest in all 24 cases. CONCLUSION CTA and CTP seem to be promising radiological examinations for the diagnosis of BD. They may be noninvasive alternatives to conventional cerebral angiography, and to the other instrumental confirmatory tests, that are unavailable or inadequate.

Donor-recipient gender mismatch affects early graft loss after kidney transplantation.

BACKGROUND We sought to determine the risk factors influencing the occurrence of early graft loss among kidney transplant recipients. STUDY DESIGN One hundred forty-six potential donors and 230 kidney recipients were included in the study. Prior to organ procurement we collected demographic data as well as hemodynamic data of mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, systemic vascular resistance index acquired by means of a thermodilution method. The recipient data included age, gender, prior hemodialysis period, panel-reactive antibodies, cold ischemia time, renal insufficiency cause, and donor-recipient gender mismatch. We assessed the influence of the data on graft loss at 30 days after renal transplantation. To confirm the relationships, we performed statistical analyses using chi-square, Fisher exact, and V. Cramer tests. RESULTS There were no significant relationships between the analyzed parameters and early graft loss in the study group except for gender mismatch. The 71 female recipients of male kidneys showed the lowest graft survival: donor/recipient male/female 89%; donor/recipient female/male 97%; no mismatch 97% (P=.01). CONCLUSIONS Female recipients of male kidneys may experience a greater risk of early graft loss compared with all other gender combinations.

Influence of angiotensin I‐converting enzyme polymorphism on development of post‐transplant erythrocytosis in renal graft recipients

Abstract:  Background:  Post‐transplant erythrocytosis (PTE) is estimated at 5–20%. Angiotensin II generated by angiotensin I‐converting enzyme (ACE) stimulates erythropoiesis. The highest activity of ACE is observed in DD genotype. The question arises if ACE gene polymorphism influences PTE.

Apnea test in the determination of brain death in patients treated with extracorporeal membrane oxygenation (ECMO)

Extracorporeal Membrane Oxygenation (ECMO) is a well-established method of support in patients with severe respiratory and/or circulatory failure. Unfortunately, this invasive method of treatment is associated with a high risk of neurological complications including brain death. Proper diagnosis of brain death is crucial for the termination of futile medical care. Currently, the legal system in Poland does not provide an accepted protocol for apnea tests for patients on ECMO support. Veno-arterial ECMO is particularly problematic in this regard because it provides both gas exchange and circulatory support. CO₂ elimination by ECMO prevents hypercapnia, which is required to perform an apnea test. Several authors have described a safe apnea test procedure in patients on ECMO. Maximal reduction of the sweep gas flow to the oxygenator should maintain an acceptable haemoglobin oxygenation level and reduce elimination of carbon dioxide. Hypercapnia achieved via this method should allow an apnea test to be conducted in the typical manner. In the case of profound desaturation and an inadequate increase in the arterial CO₂ concentration, the sweep gas flow rate may be increased to obtain the desired oxygenation level, and exogenous carbon dioxide may be added to achieve a target carbon dioxide level. Incorporation of an apnea test for ECMO patients is planned in the next edition of the Polish guidelines on the determination of brain death.

CT Angiography in the Diagnosis of Brain Death

Summary Brain death is defined as the irreversible cessation of functioning of the entire brain, including the brainstem. Brain death is principally established using clinical criteria including coma, absence of brainstem reflexes and loss of central drive to breathe assessed with apnea test. In situations in which clinical testing cannot be performed or when uncertainty exists about the reliability of its parts due to confounding conditions ancillary tests (i.a. imaging studies) may be useful. The objective of ancillary tests in the diagnosis of brain death is to demonstrate the absence of cerebral electrical activity (EEG and evoked potentials) or cerebral circulatory arrest. In clinical practice catheter cerebral angiography, perfusion scintigraphy, transcranial Doppler sonography, CT angiography and MR angiography are used. Other methods, like perfusion CT, xenon CT, MR spectroscopy, diffusion weighted MRI and functional MRI are being studied as potentially useful in the diagnosis of brain death. CT angiography has recently attracted attention as a promising alternative to catheter angiography – a reference test in the diagnosis of brain death. Since 1998 several major studies were published and national guidelines were introduced in several countries (e.g. in France, Austria, Switzerland, the Netherlands and Canada). This paper reviews technique, characteristic findings and criteria for the diagnosis of cerebral circulatory arrest in CT angiography.

Evolution of apnoea test in brain death diagnostics

The concept of brain death (BD) was initially described in 1959 and subsequently became widely accepted in the majority of countries. Nevertheless, the diagnostic guidelines for BD markedly differ, especially regarding the apnoea test (AT), a crucial element of clinical BD confirmation. The current basic guidelines recommend preoxygenation rather than disconnection from the ventilator and insertion of an oxygen insufflation catheter into the endotracheal tube. Although a properly prepared and conducted AT is relatively safe, it has to be aborted in cases of serious disturbances, such as severe cardiac arrhythmia, cardiac arrest, hypotension, hypercarbia, desaturation and tension pneumothorax. These complications may be more frequent in patients with previously existing risk factors, such as poor oxygenation, severe acidosis, hypotension and cardiac rhythm disturbances. Airway injuries can occur if the insufflation catheter is placed too deep or catheter-related obstruction of the intubation tube occurs. It is widely accepted that AT should be performed as the very last BD diagnostic procedure due to its possible lethal consequences. Reports concerning the possible pitfalls of AT and confounding situations have inspired attempts to determine the most effective and safe method of AT. The use of CPAP with oxygen supplementation is becoming highly popular. CPAP can be generated in three manners: directly by the ventilator; through the use of a CPAP valve with a reservoir; and through the use of a highly traditional T-piece system with a reservoir bag connected to distal tubing immersed in water.

Original Protocol Using Computed Tomographic Angiography for Diagnosis of Brain Death: A Better Alternative to Standard Two-Phase Technique?

BACKGROUND The application of computed tomographic angiography (CTA) for the diagnosis of brain death (BD) is limited because of the low sensitivity of the commonly used two-phase method consisting of assessing arterial and venous opacification at the 60th second after contrast injection. The hypothesis was that a reduction in the scanning delay might increase the sensitivity of the test. Therefore, an original technique using CTA was introduced and compared with catheter angiography as a reference. MATERIAL AND METHODS In a prospective multicenter trial, 84 clinically brain-dead patients were examined using CTA and catheter angiography. The sensitivities of original CTA technique, involving an arterial assessment at the 25th second and a venous assessment at the 40th second, and the standard CTA, involving an arterial and venous assessment at the 60th second, were compared to catheter angiography. RESULTS Catheter angiography results were consistent with the clinical diagnosis of BD in all cases. In comparison to catheter angiography, the sensitivity of original CTA technique was 0.93 (95%CI, 0.85-0.97; p<0.001) and 0.57 (95%CI, 0.46-0.68; p<0.001) for the standard protocol. The differences were statistically significant (p=0.03 for original CTA and p<0.001 for standard CTA). Decompressive craniectomy predisposes to a false-negative CTA result with a relative risk of 3.29 (95% CI, 1.76-5.81; p<0.001). CONCLUSIONS Our original technique using CTA for the assessment of the cerebral arteries during the arterial phase and the deep cerebral veins with a delay of 15 seconds is a highly sensitive test for the diagnosis of BD. This method may be a better alternative to the commonly used technique.

Graft Infection in Kidney Recipients and Its Relation to Transplanted Kidney Function

INTRODUCTION Following kidney transplantation, septic complications are the leading causes of therapeutic failure including recipient death or graft removal. The serum creatinine level is one of the earliest metrics of kidney metabolic function. We examined the influence of graft infection on serum creatinine levels in kidney recipients. STUDY DESIGN We analyzed the function of 220 kidneys transplanted in nine centers in Poland. The kidneys were recovered from 146 multiorgan donors. Donor urea and creatinine levels were within the normal range. We investigated the influence of perioperative graft infection incidence on recipient creatinine levels at 1, 2, 3, 7, 14, 30, 90, and 180 days after kidney transplantation. The association of the serum creatinine level with categorical variables was assessed using either Student t test analysis of variance and multivariate techniques. In all analyses P<.05 indicated statistical significance. RESULTS There were 25 graft infections revealing a significant relationship with increased recipient serum creatinine level after kidney transplantation (P=.003). Multivariate analysis confirmed the impact of infection. CONCLUSION Perioperative kidney graft infection influenced graft funtion in the early and late periods post-transplantation.

Reversal to Whole-Brain Death Criteria After 15-Year Experience With Brain Stem Death Criteria in Poland

Polish brain-death criteria, similar to the original Harvard criteria, were published in 1984. In 1990, they were converted to brainstem death criteria, and were revised twice, in 1994 and in 1996. However, they could not be used in many complicated clinical situations such as intoxication, metabolic alterations, major facial injury, infratentorial lesions, and cervical spinal cord injury. The new Polish Transplant Act, passed by the Polish Parliament in 2005, recommends implementation of criteria for whole-brain death for brain-death diagnosis. In 2007, the Polish Ministry of Health Commission outlined new Polish brain-death criteria. Optional use of instrumental confirmatory tests was implemented in the new Polish national code of practice for the diagnosis of brain death in adults. In children up to age 2 years, instrumental tests are obligatory. Initially, there were problems in understanding the new, slightly more complicated classifications of primary and secondary brain injuries, infratentorial and supratentorial processes, modified apnea test. A broad commentary that addressed the most frequently asked questions was published in Anesthesiology and Intensive Therapy, the official journal of the Polish Society of Anaesthesiology and Intensive Therapy. This article dealt with most of the problems associated with implementation of the new criteria for diagnosis of brain death.

Risk Factors for Septic Complications in Kidney Transplant Recipients

INTRODUCTION Septic complications following kidney transplantation are a leading cause of therapeutic failure. An early diagnosis may protect the recipient from the severe consequences of sepsis. We sought to determine the risk factors influencing the occurrence of septic complications among kidney transplant recipients. MATERIALS AND METHODS The 146 potential donors included in the study were evaluated for brain stem death criteria. Supportive management included mechanical ventilation to normocapnia, rewarming, as well as fluid and electrolyte replacement. Dopamine infusions and desaminovasopressin were titrated to predetermined mean arterial pressure (MAP). Central venous pressure (CVP) was maintained at 8 to 11 mm Hg. Hemodynamic data were acquired by the thermodilution method prior to organ procurement: MAP, CVP, pulmonary capillary wedge pressure (PCWP), and systemic vascular resistance index (SVRI). Recipient data included age, gender, period of prior hemodialysis, panel reactive antibodies, cold ischemia time, and cause of renal insufficiency. The 232 kidney recipients were examined for occurrence of septic complications including septicemia, pneumonia, peritonitis, or graft infection. RESULTS Kidney transplants from donors with MAP < 70 mm Hg and SVRI < 1200 dyne x s/cm(5) x m(2) showed a significantly higher occurrence of septic complications in recipients (P < .05) where mortality rate was also significantly greater (P < .01). CONCLUSIONS MAP < 70 mm Hg and SVRI < 1200 dyne x s/cm(5) x m(2) among organ donors predicted greater occurrence of septic complications and increased mortality among kidney transplant recipients.