Behr Au

99mTc-HMPAO SPECT in the diagnosis of brain death

ObjectiveTo evaluate the effectiveness of single proton emission tomography (SPECT) with 99mTc-HMPAO in the diagnosis of brain death (BD).DesignProspective study in comatose and brain-dead patients.SettingNeurologic ICU.Patients and methodsFifty comatose patients (age range: 10 days-75 years) were submitted to SPECT study. In 21 of them (42%) reversible factors (e.g., influence of drugs affecting the central nervous system) were present. Thirty-eight patients were clinically brain-dead, while the remaining 12 were tested both in pre-terminal conditions and after the clinical onset of BD.]InterventionsBrain SPECT following i.v. injection of 99mTc-HMPAO (300–1100 MBq), using a 4-headed gamma-camera (20 min, 360 °, 88 images).Measurements and resultsAll patients tested in pre-terminal conditions showed preserved brain perfusion. Two of them had flat EEGs despite the absence of any reversible cause of coma; three patients survived, but remained in persistent vegetative states. SPECT confirmed the diagnosis of BD in 45 out of 47 patients (95.7 %), clearly showing the arrest of brain perfusion (picture of “empty skull”); in two clinically brain-dead children (aged 10 days and 12 months, respectively) weak perfusion of the basal ganglia, thalamus and/or brain stem was still present, precluding the diagnosis of BD; both of them died a few days later.ConclusionsOur results confirm the reliability of SPECT in the diagnosis of BD. A problem arises about its effectiveness in brain-dead children, but this seems to be a matter of definition of BD and cerebral viability, rather than a limit of SPECT.

Role of short latency evoked potentials in the diagnosis of brain death

OBJECTIVE The aim of this study is to confirm the effectiveness of auditory brain-stem responses (ABRs) and somatosensory evoked potentials (SEPs) in the diagnosis of brain death (BD). METHODS ABRs and SEPs were recorded at the same session in 130 BD patients (age range 8-77 years, 81 male and 49 female). Twenty-four cases were submitted to serial recordings from preterminal conditions through BD. RESULTS ABRs were absent in 92 cases (70.8%), only waves I or I-II were present in 32 cases (24.6%), while in the remaining 6 patients (4.6%) waves V and/or III were still present, excluding the death of the brain-stem. In 4 cases (3.1%) SEPs showed the absence of all components following the cervical N9, preventing the diagnosis of BD. Among 126 cases (96.9%) with preserved cervical N9-N13 SEPs confirmed the absence of brain-stem activity in 122 cases (93.7%), in whom no waves following P11 or P13 were recordable. SEPs excluded the diagnosis of BD in the remaining 4 cases (3.2%) showing preserved P14 and/or N18. In all pre terminal patients the far-field P14-N18 were present, and their disappearance was closely related to the onset of BD. CONCLUSIONS The combined us of ABRs and SEPs was able to confirm BD in almost all patients, providing an objective confirmation of the diagnosis, and to exclude it in 7 cases, thus improving the reliability of diagnosis.

Multimodality evoked potentials (auditory, somatosensory and motor) in coma

Auditory brainstem responses (ABRs) have proved to be significantly related to outcome, both in severe head injury and brain hemorrhage. Nevertheless, the usefulness of ABR is limited by the anatomic extent of the investigated pathways. The combined use of ABRs and somatosensory evoked potentials (SEPs) improves the outcome prediction in comparison to the use of only one modality. It mainly decreases the rate of false negatives, since patients with severe hemispheric damage sparing the brain stem may have a poor outcome despite normal ABRs. The use of motor evoked potentials (MEPs) from magnetic transcranial stimulation is also significantly related to outcome: it appears to be far superior to the clinical evaluation of motor responses, while the combined use of MEPs and SEPs gives a new opportunity of checking sensorimotor dysfunction. ABRs and SEPs may also be useful tools in the confirmation of brain death, the kernel of which is the assessment of brainstem death: they allow to check lemniscal pathways, which cannot be properly evaluated by clinical examination, and provide an objective confirmation of absence of brain stem activity.

A Review of Local Anesthetic Systemic Toxicity Cases Since Publication of the American Society of Regional Anesthesia Recommendations: To Whom It May Concern.

Abstract Local anesthetic systemic toxicity (LAST) occurrence may cross several medical specialties. In 2010, the American Society of Regional Anesthesia and Pain Medicine (ASRA) published the first algorithm on LAST management, introducing the use of lipid emulsion (ILE) treatment. In the present study, we retrieved the cases of LAST published between ASRA guidelines dissemination and March 2014. We analyzed the reported clinical manifestations of LAST, characteristics of affected patients, onset time of toxicity, and clinical setting. We also focused on the treatment measures that were applied in the different cases, especially on the use of ILE and adherence to ASRA recommendations. Despite the limits of a review of case reports, the present study calls attention to the insidious nature of LAST, especially its atypical manifestations, and shows that ILE may currently be underadministered in daily clinical practice, especially in nonanesthesiology practice.

Auditory and somatosensory evoked potentials in coma following spontaneous cerebral hemorrhage: early prognosis and outcome

The aim of this study was to check the prognostic power of auditory brain-stem responses (ABRs) and somatosensory evoked potentials (SEPs) in coma following spontaneous cerebral hemorrhage. Seventy patients comatose following subarachnoidal or hypertensive hemorrhage were submitted to ABR and SEP recordings during the acute phase of clinical course. Twenty-one patients survived (30%), two remained vegetative (2.9%) and 47 died (68.1%). The Glasgow Coma Score (GCS) was significantly related to the outcome (P < 0.001), but showed a low sensitivity, since about 50% of patients with GCS = 5-8 died or remained vegetative. ABRs and SEPs showed a much closer correlation with outcome (P < 0.001): their combined use allowed there to be a sensitivity of 96%, a specificity of 90% and a predictive power of 96%; the relative risk of poor outcome in patients with at least one abnormal modality was equal to 223 times the one for patients with normal evoked potentials. Moreover, in surviving patients a significant relationship appeared to exist between abnormalities of SEPs during the acute phase and the severity of disability. Our results confirm the prognostic effectiveness of short latency evoked potentials in cerebral hemorrhage: they are far superior to clinical data, being able to yield a marked decrease of falsely optimistic predictions.

EEG monitoring of carotid endarterectomy with routine patch-graft angioplasty : an experience in a large series

Four hundred and thirty-nine carotid endarterectomies (CEAs) with routine use of patchgraft angioplasty were performed in 375 patients; the indwelling shunt was used only in patients showing clamp-related EEG abnormalities. Five patients showed EEG abnormalities just after head positioning, which reversed after removal of head hyperextension; three cases suffered EEG flattening due to severe bradycardia or cardiac arrest before carotid clamping, which promptly reversed after treatment. Clamp-related EEG abnormalities appeared in 106 operations (24.2%) and all reversed after the insertion of the indwelling shunt; patients with occlusion of the contralateral internal carotid artery showed a 68.8% rate of EEG clamp-related changes. The short term follow-up (one month after the operation) showed six minor strokes with complete recovery (1.37%), one intraoperative stroke (0.23%), three delayed major strokes (0.69%) and three neurological deaths (0.69%). The long-term follow-up over an average of 42 months showed a 3.7% rate of relevant neurological complications (ie permanent deficits + death) and a 3.16% rate significant restenosis or occlusion of the operated carotid artery. Our results show that the routine use of EEG monitoring and patch-graft angioplasty allow to perform CEAs with a very high degree of safety, improving the clinical course of the disease.

Is Prevention Better Than Cure?: Local Anesthetics in Brugada Syndrome.

and may have received sedative medication. Hence, for reasons related to safety and practicality, assessments were performed in a hospital stretcher in the 30degree head-up position—both before and after brachial plexus blockade. Dr Johnston is correct that we did not pursue formal pulmonary function testing for patients enrolled in our trial. Although the latter would have raised obvious feasibility issues given our trial’s “real-world” context, conditions associated with abnormal spirometry represented exclusion criteria, including any history of obstructive or restrictive pulmonary disease, neuromuscular disease, body mass index greater than 35 kg/m, and any known or suspected phrenic nerve palsy or diaphragmatic dysfunction. As stated, our analysis was based on an intention-to-treat approach in that preblock diaphragmatic ultrasonography was performed and baseline measurements were taken; were a patient found to have undiagnosed diaphragmatic dysfunction during the preblock scan, such a patient was to be included in the analysis. However, in our cohort of 64 patients, there were no such instances. Regarding ultrasound probe positioning, all ultrasonographic diaphragm scans in our randomized controlled trial were performed by a single investigator (S.D.P.) using the same approach for all patients in both groups, and all reasonable efforts were taken to diligently maintain consistent ultrasound windows preblock and postblock to extract the highest-quality data. In brief, patients were maintained in a constant position for all preblock and postblock assessments. Stretchers were not readjusted, and, whenever possible, the probe was positioned in the same location and at the same approximate angle for all assessments. As Dr Johnston would be aware, in any event of a real-time ultrasound examination of a live patient, the process is dynamic. This inherently requires ongoing small adjustments of probe position and beam angulation to capture the optimal image for measurement.When hemidiaphragmatic paralysis caused by phrenic nerve blockade occurs, there is a resultant cephalad migration of the hemidiaphragm as the muscle loses tone and the abdominal contents exert cephalad pressure from below. In such instances, careful probe repositioning and adjustment of beam angle are expected to be required to regain visualization of the diaphragm. In our experience, this in fact is another “soft sign” of diaphragmatic dysfunction. Simply placing the probe at the exact same (and fixed) position and angle after the study intervention (brachial plexus block) as was used before would

Ultrasound-Guided Interscalene and Supraclavicular Blocks

The ultrasound-guided nerve block technique has been in use now for about 15 years, and its diffusion is steadily growing with optimal clinical results. The main advantage in comparison with the other techniques consists in the direct visualization of the local anesthetic spreading around the nervous structures to be blocked. The ultrasound guidance also allows us to follow in real time what happens under the skin layer, with a close control on the needle approaching its target, thus reducing the risk of damage to any sensitive anatomical structures, such as blood vessels or the pleura.