Hyperventilation in Adult TBI Patients: How to Approach It?

Hyperventilation is a commonly used therapy to treat intracranial hypertension (ICTH) in traumatic brain injury patients (TBI). Hyperventilation promotes hypocapnia, which causes vasoconstriction in the cerebral arterioles and thus reduces cerebral blood flow and, to a lesser extent, cerebral blood volume effectively, decreasing temporarily intracranial pressure. However, hyperventilation can have serious systemic and cerebral deleterious effects, such as ventilator-induced lung injury or cerebral ischemia. The routine use of this therapy is therefore not recommended. Conversely, in specific conditions, such as refractory ICHT and imminent brain herniation, it can be an effective life-saving rescue therapy. The aim of this review is to describe the impact of hyperventilation on extra-cerebral organs and cerebral hemodynamics or metabolism, as well as to discuss the side effects and how to implement it to manage TBI patients.

Neuroprotective Potentials of Natural Vitamin E for Cerebral Small Vessel Disease

Cerebral small vessel disease (CSVD) refers to a spectrum of clinical and neuroimaging findings resulting from pathological processes of various etiologies affecting cerebral arterioles, perforating arteries, capillaries, and venules. It is the commonest neurological problem that results in significant disability, but awareness of it remains poor. It affects over half of people over 65 years old and inflicts up to third of acute strokes, over 40% of dementia, and a significant decline in physical ability in otherwise asymptomatic, aging individuals. Moreover, the unifying theory for the pathomechanism of the disease remains elusive and hence the apparent ineffective therapeutic approaches. Given the growing literature for natural vitamin E (tocopherols and tocotrienols) as a potent antioxidant, this chapter attempts to consolidate the contemporary evidence to shed plausible insights on the neuroprotective potentials of natural vitamin E in addressing the heterogenous CSVD spectrum, in health and in disease.

Small vessel disease

‘Small vessel disease’ describes a combination of neuroradiological and clinical features that are due to an intrinsic disorder of the small cerebral arterioles, capillaries, and venules in varying proportions. It is very common, usually sporadic, although rare monogenic forms are well described. The commonest presentations are with stroke or cognitive impairment. The cause of the small vessel abnormalities in the sporadic form is not well understood and the brain damage is generally attributed to ischaemia secondary to the vessel abnormality. However, evidence for altered microvessel function and blood brain barrier failure is accumulating. The commonest risk factors are increasing age, hypertension, smoking, and diabetes, but environmental and lifestyle factors are also important although poorly understood. Whether the imaging features or incidence of small vessel-related stroke or dementia vary by world region is unknown. We review current knowledge on presentation, aetiology, incidence, and prevalence of sporadic small vessel disease.

Endothelial prostaglandin D2 opposes angiotensin II contractions in mouse isolated perfused intracerebral microarterioles

Hypothesis: A lack of contraction of cerebral microarterioles to Ang II (“resilience”) depends on cyclooxygenase (COX) and lipocalin type prostaglandin D sythase L-PGDS producing PGD2 that activates prostaglandin D type 1 receptors (DP1Rs) and nitric oxide synthase (NOS). Materials & Methods: Contractions were assessed in isolated, perfused vessels and NO by fluorescence microscopy. Results: The mRNAs of penetrating intraparenchymal cerebral microarterioles versus renal afferent arterioles were >3000-fold greater for L-PGDS and DP1R and 5-fold for NOS III and COX 2. Larger cerebral arteries contracted with Ang II. However, cerebral microarterioles were entirely unresponsive but contracted with endothelin 1 and perfusion pressure. Ang II contractions were evoked in cerebral microarterioles from COX1 –/– mice or after blockade of COX2, L-PGDS or NOS and in deendothelialized vessels but effects of deendothelialization were lost during COX blockade. NO generation with Ang II depended on COX and also was increased by DP1R activation. Conclusion: The resilience of cerebral arterioles to Ang II contractions is specific for intraparenchymal microarterioles and depends on endothelial COX1 and two products that are metabolized by L-PGDS to generate PGD2 that signals via DP1Rs and NO.

Efektivitas Intervensi Motor Imagery (MI) terhadap Rehabilitasi Pasien Post stroke: A Systematic Review

Background: Motor Imagery (MI) is an intervention to improve motor skills in post stroke hemiparesis patients by focusing on weak body parts. Objective: To describe the effectiveness of providing MI in the rehabilitation of post stroke patients. Method: The database used to identify suitable articles obtained from Scopus, ProQuest and Pubmed was limited to the last 5 years of publication from 2016 to 2020, English, and fulltext articles. The literature review used the keyword "Motor Imagery" AND "Stroke Rehabilitation". In searching articles used "AND". Only 8 articles met the inclusion criteria. This review was from these 8 articles. Results: MI has effectiveness in cognitive, sensory and motor post-stroke patients by stimulating neuroplasticity in various areas of the brain so that it accelerates the increase in O2, glucose and various metabolites that lead to increased regional metabolism through dilation of cerebral arterioles and capillaries. MI which is given routinely will help the recovery of motor function of post-stroke patients and increase patient independence. Conclusion: MI has a lot of effectiveness in the rehabilitation of post stroke patients. Suggestion: MI is considered necessary to be applied in hospitals in Indonesia. Keywords: motor imagery; stroke; rehabilitation ABSTRAK Latar belakang: Motor Imagery (MI) merupakan intervensi untuk meningkatkan keterampilan motorik pada pasien hemiparesis post stroke dengan berfokus pada bagian tubuh yang lemah. Tujuan: Untuk menjabarkan efektivitas pemberian MI pada rehabilitasi pasien post stroke. Metode: Database yang digunakan dalam penelitian ini adalah Scopus, Proquest dan Pubmed terbatas untuk publikasi 5 tahun terakhir dari 2016 hingga 2020, full text article dan berbahasa Inggris. Kata kunci yang digunakan adalah “Motor Imagery” AND “Stroke Rehabilitation”. Systematic review ini menggunakan 8 artikel yang sesuai dengan kriteria inklusi. Hasil: MI memiliki efektivitas pada kognitif, sensorik dan motorik pasien post stroke dengan merangsang neuroplastisitas pada berbagai area otak sehingga memperlancar peningkatan O2, glukosa dan berbagai metabolit yang mengarah ke peningkatan metabolisme regional melalui dilatasi arteriol serebral dan kapiler. Motor Imagery (MI) yang diberikan secara rutin akan membantu pemulihan fungsi motorik pasien post stroke dan meningkatkan kemandirian pasien. Simpulan: MI memiliki banyak efektivitas pada rehabilitasi pasien post stroke Saran: MI dipandang perlu untuk diterapkan di rumah sakit yang ada di Indonesia. Kata kunci: motor imagery; stroke; rehabilitation

Abstract 140: Vascular Structure in Brain: Lack of Small Vessel Recovery Following Hypertension

Vascular remodeling is a feature of small vessel disease (SVD), predictive of vascular events, brain injury, and cognitive decline. Hypertension alters vascular structure including diameter and cross-sectional area (CSA) of the vessel wall. While effects of hypertension on large arteries have been studied relatively widely, detailed quantification, including recovery from hypertension in microvessels, is rare. Previously, angiotensin II (Ang II)-dependent hypertension produced increased CSA but reduced internal diameter (ID) of cerebral arterioles (inward remodeling) in brain. Because cerebral arterioles are targets of SVD, we examined the hypothesis that brain microvessels can recover from hypertension after return of mean arterial pressure (MAP) to normal levels. MAP was measured using radiotelemetry in adult male C57BL6J mice at baseline, during infusion of vehicle or Ang II (1.4 mg/kg per day using osmotic mini-pumps) for 28 days, and during a 28 day recovery period (n=5 in each group). Prior to treatment, MAP was similar in both groups, with MAP remaining stable in vehicle treated mice. With Ang II treatment, MAP began to rise on day 3, steadily increasing until day 28. On day 30, MAP began to decrease, reaching levels seen with vehicle on days 46-47. In anesthetized mice, we measured pressure, diameter, and CSA of the vessel wall in maximally dilated arterioles (baseline diameter of 62±3 microns) at 1, 3, 7, 14, 28, and 56 days after pump implantation (n=7-9 in each group). At day 1, ID and CSA were similar in both groups. With vehicle, there was no significant change in CSA or ID at any time point. With Ang II, CSA increased at day 7 and was maintained at days 14 and 28 (P=0.023). ID did not change at day 3 or 7, but was reduced (by ~15%, P=0.011) at 14 and 28 days. During recovery (day 56), CSA returned 63% of the way to normal (compared to vehicle), while ID remained at day 14 and 28 values. In conclusion, CSA changed rapidly during hypertension onset and largely recovered with a reduction in MAP. Inward remodeling developed slowly and did not recover after return of MAP to control levels. The lack of recovery after hypertension has implications for the impact of SVD including hypoperfusion, impaired vasodilation, and augmented injury during ischemia.