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Brown adipose tissue (BAT) is an endocrine adipose tissue with attributes to dissipate energy as heat in response to changes in temperature and diet. Infrared thermography (IRT) has been studied in recent years in the assessment of BAT thermogenesis, as an option to positron emission tomography - computed tomography (PET-CT), because of several advantages. We performed a systematic review on the use of IRT in BAT assessment. Comprehensive online search was performed in different databases. The QUADAS 2 tool was used to evaluate studies' quality. 12 studies fit the inclusion criteria, whereas only one of these was considered of low risk of bias. 10 studies were favorable to IRT appliance in BAT evaluation, observing elevation of supraclavicular skin temperature correlated with BAT activity. Studies were heterogeneous in design, and a meta-analysis was precluded. Further studies with similar methodologies are needed. Conclusion: Despite the large number of published methodologies, IRT is a promising method for detecting BAT activation. Current knowledge already allows a better understanding of thermography to improve and standardize the technique.

Background: Morphological alterations in intracranial pressure (ICP) pulse waveform (ICPW) secondary to intracranial hypertension (ICP &gt, 20 mmHg) and a reduction in intracranial compliance (ICC) are well known indicators of neurological severity. The exclusive exploration of modifications in ICPW after either the loss of skull integrity or surgical procedures for intracranial hypertension resolution is not a common approach studied. The present study aimed to assess the morphological alterations in ICPW among neurocritical care patients with skull defects and decompressive craniectomy (DC) by comparing the variations in ICPW features according to elevations in mean ICP values. Methods: Patients requiring ICP monitoring because of acute brain injury were included. A continuous record of 10 min-length for the beat-by-beat analysis of ICPW was performed, with ICP elevation produced by means of ultrasound-guided manual internal jugular vein compression at the end of the record. ICPW features (peak amplitude ratio (P2/P1), time interval to pulse peak (TTP) and pulse amplitude) were counterweighed between baseline and compression periods. Results were distributed for three groups: intact skull (exclusive burr hole for ICP monitoring), craniotomy/large fractures (group 2) or DC (group 3). Results: 57 patients were analyzed. A total of 21 (36%) presented no skull defects, 21 (36%) belonged to group 2, whereas 15 (26%) had DC. ICP was not significantly different between groups: ±15.11 for intact, 15.33 for group 2 and ±20.81 mmHg for group 3, with ICP-induced elevation also similar between groups (p = 0.56). Significant elevation was observed for the P2/P1 ratio for groups 1 and 2, whereas a reduction was observed in group 3 (elevation of ±0.09 for groups 1 and 2, but a reduction of 0.03 for group 3, p = 0.01), and no significant results were obtained for TTP and pulse amplitudes. Conclusion: In the present study, intracranial pressure pulse waveform analysis indicated that intracranial compliance was significantly more impaired among decompressive craniectomy patients, although ICPW indicated DC to be protective for further influences of ICP elevations over the brain. The analysis of ICPW seems to be an alternative to real-time ICC assessment.

Background: Invasive monitoring of intracranial pressure (ICP) is currently the gold standard method for the safe diagnosis and treatment of intracranial hypertension (ICHy), but it is subject to hemorrhage, infection and malfunction. Ultrasound of the optic nerve sheath diameter (ONSD) has been applied as a non-invasive alternative that is cost effective and available at the bedside. However, ONSD time-lapse behavior in a set of ICHy and its relief by means of whether saline infusion or surgery is still unknown. The objective of this study was to correlate intracranial pressure and ultrasonography of the optic nerve sheath in an experimental animal model of ICHy, and the interval needed to ONSD to return to its baseline levels.Methods: An experimental study was conducted on 30 male and female pigs weighing about 20 kg. The diameter of the optic nerve sheath was evaluated by ultrasound at different measures of ICP given by intraventricular catheter and intracranial balloon inflation, saline infusion and balloon deflation. Laboratory and hemodynamic data were collected from the animals. ICP and ONSD values were correlated at each time point of the study.Results: All the variables obtained by ONSD ultrasonography as left optic nerve, right optic nerve and average of optic nerve sheath (AON) diameter were statistically significant to estimate ICP value. ONSD values changed immediately at balloon inflation, with a delay of 30 minutes average to return to baseline levels after balloon deflation (p = 0.016). No statistical significance was observed in ICP and ONSD values with hypertonic saline infusion. Correlation between ICP and ONSD was linear and can be estimated using the formula: -80.5 + 238.2 x AON, in this swine model. Conclusion: In the present study, ultrasound of optic nerve sheath diameter disclosed linear correlation with ICP, although a short delay in returning to its baseline levels may be observed in the case of sudden intracranial hypertension relief.

In the last decades, the development of new noninvasive technologies in critical care allowed physicians to continuously monitor clinical parameters, aggregating important information that has been previously inaccessible or restricted due to the invasiveness of the existing techniques. The aim of this chapter is to present noninvasive methods in use on intensive care units (ICU) for brain injured patients monitoring, collaborating to the diagnosis and follow-up, aiding medical teams to achieve better outcomes.

Intracranial pressure (ICP) can be analyzed for its absolute value, usually in mmHg or cmH2O, its tendency over time and the waveform of its pulse. This chapter will focus on the waveform of the ICP pulse (ICPwf), already observed since 1881, and for a long time not understood. Studies conducted in recent decades show the correlation between the ICPwf and intracranial compliance (ICC), another important clinical parameter added to the practice in the second half of the last century. ICC allows physicians early analyzing patients’ neurological conditions related to disorders resulting from variations in cerebrospinal fluid (CSF), blood and intracranial tissue volumes. This chapter is an invitation to dive into the history and development of ICPwf analysis, clinical uses already adopted and others still under study.

Introduction: One of the possible mechanisms by which the new coronavirus (SARS-Cov2) could induce brain damage is the impairment of cerebrovascular hemodynamics (CVH) and intracranial compliance (ICC) due to the elevation of intracranial pressure (ICP). The main objective of this study was to assess the presence of CVH and ICC alterations in patients with COVID-19 and evaluate their association with short-term clinical outcomes. Methods: Fifty consecutive critically ill COVID-19 patients were studied with transcranial Doppler (TCD) and non-invasive monitoring of ICC. Subjects were included upon ICU admission, CVH was evaluated using mean flow velocities in the middle cerebral arteries (mCBFV), pulsatility index (PI), and estimated cerebral perfusion pressure (eCPP), while ICC was assessed by using the P2/P1 ratio of the non-invasive ICP curve. A CVH/ICC score was computed using all these variables. The primary composite outcome was unsuccessful in weaning from respiratory support or death on day 7 (defined as UO). Results: At the first assessment (n = 50), only the P2/P1 ratio (median 1.20 [IQRs 1.00–1.28] vs. 1.00 [0.88–1.16], p = 0.03) and eICP (14 [11–25] vs. 11 [7–15] mmHg, p = 0.01) were significantly higher among patients with an unfavorable outcome (UO) than others. Patients with UO had a significantly higher CVH/ICC score (9 [8–12] vs. 6 [5–7], p &lt, 0.001) than those with a favorable outcome, the area under the receiver operating curve (AUROC) for CVH/ICC score to predict UO was 0.86 (95% CIs 0.75–0.97), a score &gt, 8.5 had 63 (46–77)% sensitivity and 87 (62–97)% specificity to predict UO. For those patients undergoing a second assessment (n = 29), after a median of 11 (5–31) days, all measured variables were similar between the two time-points. No differences in the measured variables between ICU non-survivors (n = 30) and survivors were observed. Conclusions: ICC impairment and CVH disturbances are often present in COVID-19 severe illness and could accurately predict an early poor outcome.

Background: There is a consensus on the importance of monitoring intracranial pressure (ICP) during neurosurgery, and this monitoring reduces mortality during procedures. Current knowledge of ICP and cerebrospinal fluid pulse pressure has been built thanks to more than two centuries of research on brain dynamics. Methods: Articles and books were selected using the descriptors “ICP,” “cerebrospinal fluid pulse,” “monitoring,” “Monro-Kellie doctrine,” and “ICP waveform” in electronic databases PubMed, Lilacs, Science Direct, and EMBASE. Results: Several anatomists and physiologists have helped clarify the patterns of intracranial volumes under normal and pathological conditions. Monro-Kellie doctrine was an important step in a story that is reconstructed in this article. Through documentary research, we report the contribution of important medical figures, such as Monro, Kellie, Abercrombie, Burrows, Cushing, Langfitt, Marmarou, and other physiologists and anatomists who left their marks on the history of Medicine. Conclusion: Understanding intracranial dynamics is an unfinished historical construction. Current knowledge is the result of two centuries of research that began with the investigations of Alexander Monro secundus.

OBJECTIVEThe present study was designed to answer several concerns disclosed by systematic reviews indicating no evidence to support the use of computed tomography angiography (CTA) in the diagnosis of brain death (BD). Therefore, the aim of this study was to assess the effectiveness of CTA for the diagnosis of BD and to define the optimal tomographic criteria of intracranial circulatory arrest.METHODSA unicenter, prospective, observational case-control study was undertaken. Comatose patients (Glasgow Coma Scale score ≤ 5), even those presenting with the first signs of BD, were included. CTA scanning of arterial and venous vasculature and transcranial Doppler (TCD) were performed. A neurological determination of BD and consequently determination of case (BD group) or control (no-BD group) was conducted. All personnel involved with assessing patients were blinded to further tests results. Accuracy of BD diagnosis determined by using CTA was calculated based on the criteria of bilateral absence of visualization of the internal cerebral veins and the distal middle cerebral arteries, the 4-point score (4PS), and an exclusive criterion of absence of deep brain venous drainage as indicated by the absence of deep venous opacification on CTA, the venous score (VS), which considers only the internal cerebral veins bilaterally.RESULTSA total of 106 patients were enrolled in this study; 52 patients did not have BD, and none of these patients had circulatory arrest observed by CTA or TCD (100% specificity). Of the 54 patients with a clinical diagnosis of BD, 33 met the 4PS (61.1% sensitivity), whereas 47 met the VS (87% sensitivity). The accuracy of CTA was time related, with greater accuracy when scanning was performed less than 12 hours prior to the neurological assessment, reaching 95.5% sensitivity with the VS.CONCLUSIONSCTA can reliably support a diagnosis of BD. The criterion of the absence of deep venous opacification, which can be assessed by use of the VS criteria investigated in this study, can confirm the occurrence of cerebral circulatory arrest.Clinical trial registration no.: 12500913400000068 (clinicaltrials.gov)

Summary Background Several complications make the diagnosis of brain death (BD) medically challenging and a complimentary method is needed for confirmation. In this context, computed tomography angiography (CTA) and computed tomography perfusion (CTP) could represent valuable alternatives; however, the reliability of CTA and CTP for confirming brain circulatory arrest remains unclear. Methods A systematic review was performed to identify relevant studies regarding the use of CTA and CTP as ancillary tests for BD confirmation. Results Three hundred twenty-two patients were eligible for the meta-analysis, which exhibited 87.5% sensitivity. CTA image evaluation protocol exhibited variations between medical institutions regarding which intracranial vessels should be considered to determine positive or negative test results. Conclusions For patients who were previously diagnosed with BD according to clinical criteria, CTA demonstrated high sensitivity to provide radiologic confirmation. The current evidence that supports the use of CTA in BD diagnosis is comparable to other methods applied worldwide.

ResumoObjetivoDescrever apresentação clínica incomum de sequestro pulmonar extralobar intra‐abdominal em um paciente de dois anos e nove meses e avaliar aspectos diagnósticos e de tratamento dessa patologia.Descrição do casoUma massa intra‐abdominal indefinida em topografia suprarrenal direita de feto masculino. A avaliação pós‐natal com imagens de ultrassom, tomografia computadorizada, ressonância magnética e testes laboratoriais não foi suficiente para determinar a natureza da lesão. Após dois anos, a ressecção laparoscópica da massa e o exame histopatológico do espécime cirúrgico permitiram estabelecer o diagnóstico de sequestro pulmonar extralobar intra‐abdominal.ComentáriosEssa malformação pode ser monitorada clinicamente; entretanto, a excisão cirúrgica frequentemente é feita, provavelmente devido à impossibilidade de diagnóstico com métodos não invasivos, como ocorreu no presente caso, na qual a lesão apresentou‐se em posição não habitual para sequestro pulmonar extralobar intra‐abdominal. Desse modo, a abordagem cirúrgica parece ser a chave para o diagnóstico e a condução desde tipo de malformação congênita.AbstractObjectiveTo describe an unusual clinical presentation of intra‐abdominal extralobar pulmonary sequestration in a 2‐year, 9 month‐old patient and assess diagnostic and treatment aspects of this pathology.Case descriptionAn undefined intra‐abdominal mass was identified in the right adrenal region in a male fetus. Postnatal evaluation with ultrasound images, computed tomography, magnetic resonance imaging and laboratory testing was insufficient to determine the nature of the lesion. After two years, laparoscopic resection of the mass and histopathological examination of the surgical specimen allowed to establish the diagnosis of intra‐abdominal extralobar pulmonary sequestration.CommentsThis malformation can be monitored clinically; however, surgical excision is often performed, probably due to the impossibility of attaining diagnosis with non‐invasive methods, such as in the present case, in which the lesion appeared in an unusual position for intra‐abdominal extralobar pulmonary sequestration. Therefore, the surgical approach seems to be the key to attain the diagnosis and establish the conduct for this type of congenital malformation.

Objective: To describe an unusual clinical presentation of intra-abdominal extralobar pulmonary sequestration in a 2-year, 9 month-old patient and assess diagnostic and treatment aspects of this pathology. Case description: An undefined intra-abdominal mass was identified in the right adrenal region in a male fetus. Postnatal evaluation with ultrasound images, computed tomography, magnetic resonance imaging and laboratory testing was insufficient to determine the nature of the lesion. After two years, laparoscopic resection of the mass and histopathological examination of the surgical specimen allowed to establish the diagnosis of intra-abdominal extralobar pulmonary sequestration. Comments: This malformation can be monitored clinically; however, surgical excision is often performed, probably due to the impossibility of attaining diagnosis with non-invasive methods, such as in the present case, in which the lesion appeared in an unusual position for intra-abdominal extralobar pulmonary sequestration. Therefore, the surgical approach seems to be the key to attain the diagnosis and establish the conduct for this type of congenital malformation.