Yoku Nakagawa

Effects of mild hypercapnia on somatosensory evoked potentials in experimental cerebral ischemia.

In a previous report, the authors demonstrated the effectiveness of mild hypercapnia inenhancing decreased perfusion flow in ischemic, non-infarcted brain tissues. However, the previous worklacked in verification of improvement of suppressed brain function. Therefore, this report was attempted toevaluate the effect of hypercapnia on somatosensory evoked potential (SEP), using the similar ischemicmodel as previously. The results showed that mild hypercapnia of 43 to 55 mm Hg range was beneficial notonly for enhancing decreased perfusion flow but also for restoring suppressed SEP. This report seems to bethe first publication which verifies a presence of correlation between local cortical blood flow (LCBF) andSEP under mild hypercapnia in mildly to moderately ischemic brain tissues. Stroke Vol 15, No 2, 1984

Effects of hypercapnia on enhancement of decreased perfusion flow in non-infarcted brain tissues.

The effects of hypercapnia on enhancement of reduced cerebral perfusion were re-evaluated in areas of ischemia produced by occlusion of the canine middle cerebral artery. Perfusion was measured by 85Kr (β-ray) and 135Xe (γ-ray) clearances, fluorescein angiography and diameter measurement of arteries. Between 45 and 55 mm Hg of Paco2 rCBF measured with both isotopes increased significantly. When Paco2 was elevated above 55 mm Hg, there was a remarkable dissociation in the rCBF measured by both isotopes. Cortical blood flow measured by 85Kr clearance decreased and, conversely, rCBF measured by 133Xe continued to increase. Arteries of less than 50μ in diameter in areas of ischemia dilated significantly during hypercapnia. At Paco2 above 65 mm Hg, progressive sub-pial hemorrhage and extravasation of dye were observed as side effects of hypercapnia. The use of mannitol combined with hypercapnia appeared to be harmful. A Paco2 level between 45 and 55 mm Hg increases perfusion in areas of mildly reduced rCBF. Stroke, Vol 12, No 1, 1981

Revascularization Surgery for 50 Patients with Moyamoya Disease

Moyamoya disease is a disease characterized by chronic occlusion of the circle of Willis with subsequent development of fine vascular networks in the ganglionic region and is common in Japanese people. The term “moyamoya” means puff of smoke in Japanese and represents the characteristic angiographic findings of these fine vascular networks. Although reconstructive surgery for moyamoya disease is widely accepted now [1, 2, 5–8], there is still no definite consensus as to surgical indication for patients with hemorrhagic attack [6] and as to selection of operative method for each patient [5–8].

Site and Mechanism of Vascular Stenosis under Increased Intracranial Pressure — Intracranial Venous Pressure Regulation Mechanism

Although many authors have suggested vascular congestion of venous system under increased intracranial pressure as a cause of CBF reduction, the exact site and mechanism of compression has remained obscure. The results of our previous investigations in dogs are summarized in Fig. 1. Cortical venous pressure (CVP), bridging venous pressure (bridging VP), and lateral lacunar pressure (lat lacuna P) were constantly 4–18 mmHg higher than ICP, regardless of the level of ICP, while superior sagittal sinus pressure (SSSP) is quite stable at low levels (4–6 mmHg). Thus, pressure gradients between the cortical arterial pressure and the CVP, gradually decrease as ICP is elevated, while the pressure gradient between the CVP and the SSSP continuously increases as ICP is elevated. These evidences indicate that vascular stenosis is taking place in the lateral lacuna of superior sagittal sinus.

Clinical Significance of TCP Measurements Following Intracranial Surgery

The present study was intended to find out correlations between clinical manifestations and the level and course of ICP following major intracranial surgery.

Carotid-subclavian bypass for occlusion of the subclavian artery

For surgical therapy of stenosis and occlusion of the subclavian artery, several types of extrathoracic vascular reconstructions have recently been performed, mainly in the supraclavicular fossa. Carotid-subclavian bypass is becoming a more acceptable surgical procedure than axilloaxillary bypass. We encountered three patients with these lesions who underwent common carotid-subclavian bypass with autogenous saphenous vein grafts. Their symptoms were completely relieved and pulsation of the radial artery recovered sufficiently. Restoration of inflow from the carotid artery was able to provide adequate reconstruction of the subclavian lesions. This bypass is less invasive and is efficient for such lesions in the supraclavicular position.

Aneurysm of the Vein of Galen in an Infant: Case report

A case of an aneurysm of the vein of Galen treated by a successful direct surgical procedure during the infancy is presented together with five year’s follow-up observation.

Oxygenation at high pressure (OHP) for the patients who developed mental signs after direct operation of intracranial aneurysms

脳動脈瘤術後精神症状を有する49例に対して慢性期に高気圧酸素療法を応用した. (1) OHPの急性効果は著効と中等度改善を合わせて49例中26例 (53%) で, 症状不変は8例 (16%) でOHPの有効性は高かった. (2) OHPの効果は症状の重篤度に左右されておりOHP開始前の症状が軽い程OHPの効果が認められた. (3) 脳動脈瘤部位別では内頚動脈瘤, 中大脳動脈瘤で症状の重篤な例でもOHPにより症状が改善する事が多かった. (4) OHPが有効であった症状は自発性欠如や見当識障害であり, 無効なのは無動性無言症であった. (5) 精神症状が判明した早期よりOHPを開始した例が急性効果が認められ, OHP開始まで3ヵ月以上経てしまった例は効果はほとんど期待できなかった. (6) 自然歴例とOHP例とで症状の遠隔成績を比較すると術後中等度以上の重度精神症状が認められた例ではOHP例の方が成績が優れていた.