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Background: The apnea test (AT) is an important component in the determination of brain death/death by neurologic criteria (BD/DNC) and often entails disconnecting the patient from the ventilator followed by tracheal oxygen insufflation to ensure adequate oxygenation. To rate the test as positive, most international guidelines state that a lack of spontaneous breathing must be demonstrated when the arterial partial pressure of carbon dioxide (PaCO2) ≥ 60 mm Hg. However, the loss of positive end-expiratory pressure that is associated with disconnection from the ventilator may cause rapid desaturation. This, in turn, can lead to cardiopulmonary instability (especially in patients with pulmonary impairment and diseases such as acute respiratory distress syndrome), putting patients at increased risk. Therefore, this prospective study aimed to investigate whether a modified version of the AT (mAT), in which the patient remains connected to the ventilator, is a safer yet still valid alternative. Methods: The mAT was performed in all 140 BD/DNC candidates registered between January 2019 and December 2022: after 10 min of preoxygenation, (1) positive end-expiratory pressure was increased by 2 mbar (1.5 mm Hg), (2) ventilation mode was switched to continuous positive airway pressure, and (3) apnea back-up mode was turned off (flow trigger 10 L/min). The mAT was considered positive when spontaneous breathing did not occur upon PaCO2 increase to ≥ 60 mm Hg (baseline 35–45 mm Hg). Clinical complications during/after mAT were documented. Results: The mAT was possible in 139/140 patients and had a median duration of 15 min (interquartile range 13–19 min). Severe complications were not evident. In 51 patients, the post-mAT arterial partial pressure of oxygen (PaO2) was lower than the pre-mAT PaO2, whereas it was the same or higher in 88 cases. In patients with pulmonary impairment, apneic oxygenation during the mAT improved PaO2. In 123 cases, there was a transient drop in blood pressure at the end of or after the mAT, whereas in 12 cases, the mean arterial pressure dropped below 60 mm Hg. Conclusions: The mAT is a safe and protective means of identifying patients who no longer have an intact central respiratory drive, which is a critical factor in the diagnosis of BD/DNC. Clinical trial registration DRKS, DRKS00017803, retrospectively registered 23.11.2020, https://drks.de/search/de/trial/DRKS00017803 [ABSTRACT FROM AUTHOR]

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Background: Telemedicine has rapidly emerged as an important tool in emergency neurology. In particular, reliable biomarkers of large vessel occlusions (LVOs) are critically necessary in order to identify the need for in-hospital mechanical thrombectomy (MT). Based on pathophysiological factors, we propose that the presence of head and/or gaze deviation alone signifies cortical hypoperfusion and is therefore a highly sensitive marker for the presence of LVO. Methods: We retrospectively analyzed a cohort of 160 patients, examined via telemedicine and suspected to have had an acute stroke; this included patients with ischemic or hemorrhagic stroke, transient ischemic attack, and stroke mimics. An assessment of head and gaze deviation and NIHSS score evaluation was performed. In a second analysis, patients who only had ischemia in the anterior circulation (n = 110) were evaluated. Results: Head and/or gaze deviation alone was found to be a reliable marker of LVO (sensitivity: 0.66/specificity: 0.92), as well as a sound indicator for MT (0.82/0.91), in patients with suspected ischemic stroke. The performance of this indicator further improved when patients with ischemia in the anterior circulation only were assessed (LVO: 0.70/0.93; MT: 0.86/0.90). In both analyses, head and/or gaze deviation served as a better indicator for LVO or MT compared to the prevalence of motor deficits or aphasia. Of note, in patients who had ischemia in the anterior circulation, head and/or gaze deviation performed better than the NIHSS score as an indicator for MT. Conclusion: These findings confirm that the presence of head and/or gaze deviation serves as a reliable biomarker in stroke-based telemedicine for the diagnosis of LVO, as well as a strong indicator for MT. Furthermore, this marker is just as reliable as the NIHSS score but easier to assess. We therefore suggest that any stroke patient who displays head and/or gaze deviation should immediately be scheduled for vessel imaging and subsequently transported to a MT-competent center. [ABSTRACT FROM AUTHOR]

Objective: The time preceding brain death is associated with complex dysregulation including autonomic dysfunction that may compromise organ perfusion, thus inducing final organ failure. In this study, we assessed autonomic function in patients prior to brain death. Methods: In 5 patients (2 women, median 60 years, age range 52-75 years) with fatal cerebral hemorrhage or stroke and negative prognosis, we monitored RR-intervals (RRI), systolic and diastolic blood pressure (BP), and oxygen saturation. Adjustment of mechanical ventilation remained constant. We assessed autonomic function from spectral powers of RRI and BP in the mainly sympathetic low- (LF, 0.04-0.15 Hz) and parasympathetic high-frequencies (HF, 0.15-0.5 Hz), and calculated the RRI-LF/HF-ratio as index of sympathovagal balance. Three patients required norepinephrine (0.5-1.6 mg/h) for up to 72 h to maintain organ perfusion. Norepinephrine was reduced to 0.2-0.5 mg/h within 2 h before brain death was diagnosed according to the criteria of the German Medical Association. Wilcoxon test compared average values of ten 2-min epochs determined 2-3 h (measurement 1) and 1 h (measurement 2) before brain death. Results: We found higher systolic (127.3 ± 15.9 vs. 159.4 ± 44.8 mmHg) and diastolic BP (60.1 ± 15.6 vs. 74.0 ± 15.2 mmHg), RRI-LF/HF-ratio (1.2 ± 1.6 vs. 3.9 ± 4.0), and BP-LF-powers (2.7 ± 4.8 vs. 23.1 ± 28.3 mmHg) during measurement 2 than during measurement 1 ( p < 0.05). Conclusions: The increase in BPs, in sympathetically mediated BP-LF-powers, and in the RRI-LF/HF-ratio suggests prominent sympathetic activity shortly before brain death. Prefinal sympathetic hyperactivity might cause final organ failure with catecholamine-induced tissue damage which impedes post-mortem organ transplantation. [ABSTRACT FROM AUTHOR]

Introduction: Our objective was to investigate the feasibility of lumbar drainage (LD) as a new therapeutic approach for the treatment of communicating hydrocephalus in patients with supratentorial intracerebral hemorrhage (ICH) and ventricular extension (IVH) who initially required an external ventricular drain (EVD).Methods: Three consecutive patients with ICH and severe IVH were treated with EVD immediately after admission due to acute obstructive hydrocephalus. Each patient received intraventricular fibrinolysis (IVF) starting 12 hours after admission (4 mg rtPA every 12 hours up to a maximum cumulative dose of 20 mg). Although complete clearing from blood of the third and fourth ventricles was achieved in all patients after IVF, branching off the EVD failed because of increasing intracranial pressure (ICP). Assuming a communicating, malresorptive hydrocephalus was present, a lumbar drain was placed (to allow extracorporal CSF drainage through outer CSF space).Results: In all patients, the EVD could be branched off without raising ICP (while the LD remained open), resulting in the opportunity to remove the EVD in all patients after another 24 hours (mean duration of EVD was 115 +/- 4 hours). Clamping the LD was performed every second day and development of hydrocephalus was monitored by CT. After a mean duration of 6 (5-7) days after placement, the LD could be removed. None of the patients required a VP-Shunt.Conclusion: Our preliminary data suggest that LD is a simple and reasonable alternative for treating communicating hydrocephalus after ICH and IVH. The combination of IVF to enhance clot resolution and to clear the third and fourth ventricle followed by LD may represent a new and promising approach in the therapy of hydrocephalus following severe ventricular hemorrhage. [ABSTRACT FROM AUTHOR]