{"id":664,"date":"2012-07-22T10:49:41","date_gmt":"2012-07-22T07:49:41","guid":{"rendered":"http:\/\/www.hvtd.org\/?p=664"},"modified":"2012-07-22T10:49:41","modified_gmt":"2012-07-22T07:49:41","slug":"a-loc-sendromu","status":"publish","type":"post","link":"https:\/\/www.hvtd.org\/?p=664","title":{"rendered":"A-LOC Sendromu"},"content":{"rendered":"
\n

\"\"<\/a>Akselerasyon, birim zaman i\u00e7indeki h\u0131z\u0131n de\u011fi\u015fim miktar\u0131d\u0131r. Pilotun bu akselerasyona verdi\u011fi fizyolojik yan\u0131tlar G kuvvetinin miktar\u0131na ve hareketin y\u00f6n\u00fcne ba\u011fl\u0131d\u0131r.<\/p>\n

\u0130stirahat halindeki bir ki\u015fi normal yer\u00e7ekimi kuvvetinin (1 G) etkisi alt\u0131ndad\u0131r. A\u011f\u0131rl\u0131\u011f\u0131 80 kg. olan bir pilot 2 G\u2019de 160, 9 G\u2019de 720 kilo v\u00fccut a\u011f\u0131rl\u0131\u011f\u0131na ula\u015f\u0131r. +Gz s\u0131ras\u0131nda, kalp \u00fczerindeki seviyelerde (beyin, g\u00f6z) kan damarlar\u0131ndaki hidrostatik bas\u0131n\u00e7 azal\u0131r. +Gz art\u0131\u015f\u0131 ile olu\u015fan ilk belirti periferik g\u00f6r\u00fc\u015fte azalmad\u0131r. Bunu takiben \u00e7evresel g\u00f6r\u00fc\u015fte daralma (t\u00fcnel g\u00f6r\u00fc\u015f\u00fc) ve +2 G \u00fczerinde ortaya \u00e7\u0131kan gray out\u2019dur. G kuvveti +4 Gz\u2019e ula\u015f\u0131rsa, tam g\u00f6r\u00fc\u015f kayb\u0131 (black out) meydana gelebilir; takiben i\u015fitsel ve mental fonksiyonlar etkilenebilir. Beyin kan ak\u0131m\u0131 azal\u0131r veya tamamen durursa, bilin\u00e7 kayb\u0131 (G-LOC: Loss of consciousness) ortaya \u00e7\u0131kar; tam veya g\u00f6receli inkapasitasyon olur (3).<\/p>\n

Tam inkapasitasyon; kabaca 9-21 saniyelik bilin\u00e7 kayb\u0131 durumudur. Bu s\u00fcre\u00e7te konvulsiyonlar ve spazmlar meydana gelebilir, u\u00e7u\u015f kontrolleri kaybedilir. Mental konf\u00fczyon, oryantasyon bozuklu\u011fu, stupor, apati ve hat\u0131rlama g\u00fc\u00e7l\u00fc\u011f\u00fc olabilir. Bu s\u0131rada bilin\u00e7li olarak u\u00e7a\u011f\u0131 u\u00e7urmak, karar vermek, tehditlere kar\u015f\u0131 reaksiyon g\u00f6stermek ve etkin ileti\u015fim kurmak m\u00fcmk\u00fcn de\u011fildir (2,3).<\/p>\n

A-LOC:<\/strong> G-LOC\u2019a neden olamayacak derecelerdeki +Gz kuvvetlerine k\u0131sa s\u00fcreli maruz kal\u0131nd\u0131\u011f\u0131nda veya – Gz kuvvetli bir hareketin akabinde + Gz kuvvetli manevralarda (push to pull) ortaya \u00e7\u0131kabilen, sinsi bir durum olarak tan\u0131mlanabilir. Bu durum 1980\u2019lerin sonunda ABD Deniz Kuvvetleri taraf\u0131ndan (4), ABD Hava Kuvvetleri taraf\u0131ndan N-LOC (Near Loss of Consciousness) <\/strong>olarak adland\u0131r\u0131lm\u0131\u015ft\u0131r (1). \u201cNeredeyse, hemen hemen, k\u0131smi bilin\u00e7 kayb\u0131\u201d <\/em>bi\u00e7iminde T\u00fcrk\u00e7e\u2019le\u015ftirilebilecek olan A-LOC (veya N-LOC), \u00e7ok \u00e7e\u015fitli fiziksel, fizyolojik, bili\u015fsel ve duygusal semptomlar\u0131 i\u00e7eren bir sendromdur. Pilotlar\u0131n ve u\u00e7u\u015f doktorlar\u0131n\u0131n \u00e7o\u011fu bu kavram\u0131 tam olarak bilmezler; bunu ya\u015fayan pilotlar bu konuda konu\u015fmaktan ka\u00e7\u0131n\u0131rlar veya sanki normal bir olgu gibi g\u00f6r\u00fcrler (4).<\/p>\n

ABD\u2019de yap\u0131lan bir santrif\u00fcj \u00e7al\u0131\u015fmas\u0131nda, 9 pilota tedrici artan bi\u00e7imde (arada 1 dakika istirahat bo\u015fluklar\u0131 olacak \u015fekilde), bilin\u00e7 kayb\u0131 (G-LOC) olu\u015funcaya kadar 6, 8, 10 +Gz profilleri (toplam 161 profil) uygulanm\u0131\u015f ve bunlar\u0131n 66\u2019s\u0131nda A-LOC g\u00f6zlenmi\u015ftir (5). ABD Hava Kuvvetlerinin yapt\u0131\u011f\u0131 benzer \u00e7al\u0131\u015fmada ise, 58 santrif\u00fcj u\u00e7u\u015funun 3\u2019\u00fcnde G-LOC, 37\u2019sinde N-LOC ortaya \u00e7\u0131kt\u0131\u011f\u0131 g\u00f6sterilmi\u015ftir (1).<\/p>\n

A-LOC s\u0131ras\u0131nda u\u00e7ucular G kuvvetinin ba\u015flang\u0131c\u0131ndan istirahat d\u00f6nemine kadar ge\u00e7en s\u00fcrede neler oldu\u011funu hat\u0131rlayamazlar (amnezi); nerede ve ni\u00e7in orada olduklar\u0131n\u0131, o s\u0131rada ne yapt\u0131klar\u0131n\u0131, u\u00e7ak i\u00e7i cihazlar\u0131n ikazlar\u0131n\u0131 alg\u0131layamazlar (konf\u00fczyon). En dramatik olan\u0131 ise bu s\u00fcre\u00e7te konu\u015famamalar\u0131d\u0131r (afazi); ne s\u00f6ylemek istediklerini bildiklerini ama bunu kelimelere d\u00f6kemediklerini ifade ederler. Baz\u0131lar\u0131 kendilerini mutlu, zinde ve enerjik, baz\u0131lar\u0131 tam tersine ho\u015fnutsuz ve kayg\u0131l\u0131 hissederler. Ayr\u0131ca el ve kollarda s\u0131zlama (%32), istem d\u0131\u015f\u0131 hareketler (%30), donuk-ifadesiz y\u00fcz (%56), titreme, i\u015fitme kayb\u0131 (%12) ve ge\u00e7ici paralizi (%9) gibi fiziksel semptomlar g\u00f6r\u00fclebilir (3,5).<\/p>\n

A-LOC, u\u00e7u\u015f m\u00fcrettebat\u0131n\u0131n zihinsel, fiziksel ve duygusal tepkilerini bozan sinsi bir sendromdur. Bellekte olu\u015fan bo\u015fluklar, gecikmi\u015f kendine gelme s\u00fcresi ve istemli kas kontrol\u00fcn\u00fcn kayb\u0131, u\u00e7u\u015f s\u0131ras\u0131ndaki tehlikeyi artt\u0131r\u0131r.
\nKaynaklar: <\/strong><\/p>\n

1. Balldin UI, Nunneley SA, et al. Acceleration induced near-loss of concsiousness. 74th Annual ASMA Scientific Meeting, (2003) Abs # 321<\/p>\n

2. Burton RR, Whinnery JE. Biodynamics: Sustained Acceleration. In: Dehart RL, Davis JR, eds. Fundamentals of Aerospace Medicine, 3rd ed. Philadelphia: Lippincott Williams&Wilkins; 2002:136-7.<\/p>\n

3. Campbell RD, Bagshaw M. The basics of flight physiology: effects of acceleration. Human Performance and Limitations in Aviation, 3rd ed. Cornwall: Blackwell Science; 2002:31-3.<\/p>\n

4. Johnson EG, Anderson C. A-Loc: a case report and survey. 75th Annual ASMA Scientific Meeting, (2004) Abs # 71<\/p>\n

5. Shender BS, Forster EM, Hrebien L, et al. Acceration-induced near-loss of consciousness: The A-LOC Syndrome. Aviat Space Environ Med. 2003;74:1021-28<\/p>\n

Haz\u0131rlayan:<\/strong> Dr. Levent \u015eenol (GATA Hava ve Uzay Hek. Merkezi)<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Akselerasyon, birim zaman i\u00e7indeki h\u0131z\u0131n de\u011fi\u015fim miktar\u0131d\u0131r. Pilotun bu akselerasyona verdi\u011fi fizyolojik yan\u0131tlar G kuvvetinin miktar\u0131na ve hareketin y\u00f6n\u00fcne ba\u011fl\u0131d\u0131r. \u0130stirahat halindeki bir ki\u015fi normal yer\u00e7ekimi kuvvetinin (1 G) etkisi alt\u0131ndad\u0131r. A\u011f\u0131rl\u0131\u011f\u0131 80 kg. olan bir pilot 2 G\u2019de 160, 9 G\u2019de 720 kilo v\u00fccut a\u011f\u0131rl\u0131\u011f\u0131na ula\u015f\u0131r. +Gz s\u0131ras\u0131nda, kalp \u00fczerindeki seviyelerde (beyin, g\u00f6z) kan damarlar\u0131ndaki hidrostatik bas\u0131n\u00e7 azal\u0131r. +Gz […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[6],"tags":[],"class_list":["post-664","post","type-post","status-publish","format-standard","hentry","category-bulten"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/posts\/664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=664"}],"version-history":[{"count":1,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/posts\/664\/revisions"}],"predecessor-version":[{"id":666,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=\/wp\/v2\/posts\/664\/revisions\/666"}],"wp:attachment":[{"href":"https:\/\/www.hvtd.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hvtd.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}