Role of Atelectasis in Surfactant Abnormalities Following Extracorporeal Circulation

Abstract

Surface activity of lung extracts was determined in 36 patients and 28 dogs following extracorporeal circulation. Normal results were usually found. Abnormal surface tension was demonstrated only in a few samples obtained from grossly atelectatic or congested portions of lung, normal surface tension being present in adjoining areas of the same lung. Sources of error in surface-tension measurements and factors to be considered in the interpretation of results are discussed. A possible explanation for the discrepancies in results obtained by various investigators is presented.

Comparação entre ventilação controlada a volume e a pressão no tratamento da hipoxemia no período pós-operatório de cirurgia de revascularização do miocárdio

“…A pressão exercida pelas vísceras abdominais sobre o diafragma relaxado na posição supina 14 , a pressão induzida pelo coração sobre o pulmão 15 e a manipulação cirúrgica contribuem para formação mecânica de atelectasias principalmente nas regiões pulmonares dependentes e caudais 16 . Associam-se aos fatores mecânicos, a alteração do sistema surfactante após a circulação extracorpórea 17 , aumento da permeabilidade vascular secundária à resposta inflamatória sistêmica induzida pela circulação extracorpórea 18 e lesão de isquemia e reperfusão que contribuem para formação de edema pulmonar. O edema pulmonar irá determinar um aumento da pressão hidrostática exercida pelo próprio parênquima pulmonar sobre as regiões pulmonares dependentes 19 e diminuição da difusão do oxigênio por edema alveolar.…”

“…Pressure exerted by abdominal viscerae on the relaxed diaphragm in the supine position 14 , heart-induced pressure on the lungs 15 and surgical manipulation contribute to mechanical development of atelectasis, especially in dependent and caudal pulmonary regions 16 . Changes in surfactant system after cardiopulmonary bypass 17 , vascular patency increase secondary to systemic inflammatory response induced by cardiopulmonary bypass 18 and ischemia and reperfusion inuries contributing to pulmonary edema are associated to mechanical factors. Pulmonary edema will determine an increase in hydrostatic pressure exerted by the pulmonary parenchyma on dependent pulmonary regions 19 and a decrease in oxygen spread caused by alveolar edema.…”

Συμβολη Εις Την Τεχνικην Της Αναισθησιας Κατα Την Χειρουργικην Ανοικτης Καρδιας

“…και ή ελαφρά διάτασις τών πνευμόνων, ώς και ή κατά δια στήματα εκπτυξις τούτων, προφυλάσσουν έκ τών μετεγχειρητικών άτελεκτασιών. Έν τούτοις, δεν ενδείκνυται ή μακροχρόνιος χορήγησις 0 2 προς τον σκοπόν τούτον διότι, ώς έχει άποδειχθή, τούτο προκαλεί έλάττωσιν τής επιφανειακής τάσεως τοΰ κυψελιδικού τοιχώματος δια τής άνενεργοποιήσεως τής δρώσης ουσίας επί τής επιφανείας τών πνευμό νων με αποτέλεσμα τήν δημιουργίαν άτελεκτασιών (Guest, 1966). Έξ άλλου, απεδείχθη δια πειραμάτων επί κυνών οτι, έάν ό πνεύμων πληρωθή διαδοχικώς δια C0 2 , 0 2 , Ν 2 0, ατμοσφαιρικού αέρος και Ν 2 , ό απαιτού μενος χρόνος μετά άπόφραξιν τοΰ κυρίου βρόγχου, ελαττώσεως τοΰ όγκου αυτών είς τα 7/8 τοΰ αρχικού είναι αντιστοίχως Γ 6", Γ20", Ι '42", 9'2Ι" και Ι2'6" (Lemmer και συν.…”