[Diagnosis of irreversible loss of brain function ("brain death")-what is new?]

Milestones in the history of neurocritical care

Over the last century, significant milestones have been achieved in managing critical illness and diagnosing and treating neurological diseases. Building upon these milestones, the field of neurocritical care emerged in the 1980 and 1990 s at the convergence of critical care medicine and acute neurological treatment. This comprehensive review presents a historical account of key developments in neurocritical care in both the United States and Europe, with a special emphasis on German contributions. The scope of the review encompasses: the foundations of neurocritical care, including post-operative units in the 1920s and 30s, respiratory support during the poliomyelitis epidemics in the 40 and 50 s, cardiac and hemodynamic care in the 60 and 70 s, and stroke units in the 80 and 90 s; key innovations including cerebral angiography, computed tomography, and intracranial pressure and multi-modal monitoring; and advances in stroke, traumatic brain injury, cardiac arrest, neuromuscular disorders, meningitis and encephalitis. These advances have revolutionized the management of neurological emergencies, emphasizing interdisciplinary teamwork, evidence-based protocols, and personalized approaches to care.

Exclusive color-coded duplex sonography of extracranial vessels reliably confirms brain death: A prospective study

Background

Transcranial color-coded duplex sonography (TCCD) can be used as an ancillary test for determining irreversible loss of brain function (ILBF) when demonstration of cerebral circulatory arrest (CCA) is required. However, visualization of the intracranial vessels by TCCD is often difficult, or even impossible, in this patient cohort due to elevated intracranial pressure, an insufficient transtemporal bone window, or warped anatomical conditions. Since extracranial color-coded duplex sonography (ECCD) can be performed without restriction in the aforementioned situations, we investigated the feasibility of omitting TCCD altogether, such that the ILBF examination would be simplified, without compromising on its reliability.

Methods

A total of 122 patients were prospectively examined by two experienced neurointensivists for the presence of ILBF from 01/2019-12/2021. Inclusion criteria were (i) the presence of a severe cerebral lesion on cranial CT or MRI, and (ii) brainstem areflexia. Upon standardized clinical examination, 9 patients were excluded due to incomplete brainstem areflexia, and a further 22 due to the presence of factors with a potentially confounding influence on apnea testing, EEG or sonography. A total of 91 patients were enrolled and underwent needle-EEG recording for >30 min (= gold standard), as well as ECCD and TCCD. The sonographer was blinded to the EEG result.

Results

All patients whose ECCD result was consistent with ILBF had this diagnosis confirmed by EEG (n = 77; specificity: 1). Both ECCD and EEG were not consistent with ILBF in a further 12 patients. In the remaining two patients, ECCD detected reperfusion due to long-lasting cerebral hypoxia; however, ILBF was ultimately confirmed by EEG (sensitivity: 0.975). This yielded a positive predictive value (PPV) of one and a negative predictive value of 0.857 for the validity of ECCD in ILBF confirmation. TCCD was not possible/inconclusive in 31 patients (34%).

Conclusions

The use of ECCD for the confirmation of ILBF is associated with high levels of specificity and a high positive predictive value when compared to needle-electrode EEG. This makes ECCD a potential alternative to the ancillary tests currently used in this setting, but confirmation in a multi-center trial is warranted.

Trial registration

https://www.drks.de, DRKS00017803.

Jahi McMath, a New Disorder of Consciousness

In this paper, I review the case of Jahi McMath, who was diagnosed with brain death (BD). Nonetheless, ancillary tests performed nine months after the initial brain insult showed conservation of intracranial structures, EEG activity, and autonomic reactivity to the “Mother Talks” stimulus. She was clinically in an unarousable and unresponsive state, without evidence of self-awareness or awareness of the environment. However, the total absence of brainstem reflexes and partial responsiveness rejected the possibility of a coma. Jahi did not have uws because she was not in a wakefulness state and showed partial responsiveness. She could not be classified as a LIS patient either because LIS patients are wakeful and aware, and although quadriplegic, they fully or partially preserve brainstem reflexes, vertical eye movements or blinking, and respire on their own. She was not in an MCS because she did not preserve arousal and preserved awareness only partially. The CRS-R resulted in a very low score, incompatible with MCS patients. mcs patients fully or partially preserve brainstem reflexes and usually breathe on their own. MCS has always been described as a transitional state between a coma and UWS but never reported in a patient with all clinical BD findings. This case does not contradict the concept of BD but brings again the need to use ancillary tests in BD up for discussion. I concluded that Jahi represented a new disorder of consciousness, non-previously described, which I have termed “reponsive unawakefulness syndrome” (RUS).

[Diagnostics of irreversible brain death : Limitations and potential for improvement from the perspective of transplantation officials]

BACKGROUND

In Germany, postmortem organ donation requires a diagnosis of irreversible brain death (BD) in strict compliance with the guidelines of the German Medical Association.

OBJECTIVE

Identification of factors that have a limiting effect on the initiation and execution of BD diagnostics. Identification of potential for improvement.

MATERIAL AND METHODS

Anonymous survey of transplantation officials in hospitals in Berlin, Brandenburg and Mecklenburg-Western Pomerania.

RESULTS

There is considerable heterogeneity with respect to the frequency of BD diagnostics and hospital-specific procedures, including the use of an existing consultation service. The local availability of qualified doctors and of suitable ancillary diagnostic tests has a structurally limiting effect. This is especially true for pediatric patients. Potential for improvement was seen in the identification of affected patients, the motivation of staff and the role of transplantation officials.

CONCLUSION

According to the recently amended German Transplantation Act, a centrally organized consultation service for BD diagnostics must be implemented as soon as 2021. Recommendations can be derived from the present survey and from the experience of the regionally established consultation service. In addition to neurological and neurosurgical expertise, qualified pediatricians and mobile ancillary instrumental diagnostics should also be provided. Expert advice from neurointensive care physicians should be available at an early stage in order to identify potentially affected patients. The highly variable participation of hospitals in organ donation, despite the availability of an expert diagnostic service free of charge, points to an important role of additional factors, some of which may be nonmedical in nature.

[Brain death criterion and organ donation: current neuroscientific perspective]

In der akademischen und öffentlichen Debatte wird der irreversible Hirnfunktionsausfall als Kriterium des Todes (Hirntodkriterium) immer wieder hinterfragt. Im vorliegenden Artikel werden 6 prototypische Thesen gegen das Hirntodkriterium diskutiert: 1) Nichtsuperiorität des Gehirns gegenüber anderen Organen, 2) Unsicherheit der Hirntoddiagnostik, 3) erhaltene Schmerzempfindung Hirntoter, 4) (spontane) sexuelle Reifung und erhaltene Reproduktionsfunktion Hirntoter, 5) Symmetrie von Hirntod und Embryonalphase, 6) Gleichsetzung des intensivmedizinisch erhaltenen Restorganismus Hirntoter mit dem lebenden Menschen.

Keine dieser Thesen hält einer kritischen Analyse stand. In Deutschland wird das Ganzhirntodkriterium angewendet. Der Hirntod geht mit dem völligen Ausfall jeglicher Empfindung, Bewusstheit, Mimik, Augen‑, Zungen- und Schlundmotorik, Willkürmotorik und Sexualfunktion einher (funktionelle „Enthauptung“). Medizinisch-technisch können andere Organe bzw. ihre Primitivsteuerung ersetzt werden, nicht aber das Gehirn. Das Gehirn, nicht der Körper, ist bestimmend für das menschliche Individuum. Die Gleichsetzung des künstlich erhaltenen Restorganismus, naturphilosophisch als lebendiges System interpretierbar, mit dem Organismus desselben lebenden Menschen wird durch die beliebige Reduzierbarkeit der Anzahl beteiligter Organe ad absurdum geführt. Der irreversible Hirnfunktionsausfall führt unausweichlich zum Herzstillstand, unbehandelt innerhalb von Minuten, unter Intensivtherapie i. d. R. innerhalb von Tagen. Auch beim Embryo/Fötus führt die Fehlanlage des gesamten Gehirns zum (vorgeburtlichen) Tod. Die in Deutschland gesetzliche Richtlinie zur Hirntodfeststellung hat eine im internationalen Vergleich hohe Diagnosesicherheit, es sind damit keine bestätigten Fehldiagnosen aufgetreten.