tailieunhanh - The Anaesthesia Science Viva Book - part 7

Đây là một khu vực đơn giản của giải phẫu mà Allen sửa đổi thử nghiệm có một ứng dụng lâm sàng rõ ràng, mặc dù có giá trị là tranh chấp. Nếu bạn truyền đạt thông tin cơ bản quá nhanh sau đó bạn sẽ thấy mình thảo luận về áp lực động mạch dạng sóng và giảm xóc. | CHAPTER 4 Glucagon Glucagon exerts its postive-intropic effect via an increase in the synthesis of cAMP. It is rarely used for this specific purpose. Ephedrine Ephedrine is a sympathomimetic which has both direct and indirect a- and p-effects but which is used primarily as a vasopressor. It inhibits the breakdown of noradrenaline norepinephrine by monoamine oxidase and this mixture of actions mean that its main influence on BP is via an increase in CO. Its aj-effects mediate peripheral vasoconstriction while the Pj-effects increase the force and rate of myocardial contraction. Pharmacology 203 CHAPTER 4 The anaesthesia science viva book Bioavailability Commentary Bioavailability is a simple concept whose value is disputed by some authorities. It is a subject however that can fit readily into the time frame of the viva. Make sure that you are able to define it and that you can draw the curves of concentration plotted against time of a drug that is given intravenously and one that is given by some other route. The questioning is likely to revert thereafter to a general discussion of the factors that may affect drug absorption. The viva You will be asked to define the term bioavailability and to describe how it could be measured. Bioavailability is that fraction of the dose of an administered drug that gains access to the systemic circulation and is therefore available to act at its receptor sites. It is assumed that the bioavailability of an intravenous dose is 100 or . Alternatively bioavailability can be defined simply as the ratio of the effective dose to the administered dose. It has been used most commonly as a measure following oral administration but it applies equally to drugs given by other routes of which there are many . These include rectal vaginal nasal ocular pulmonary sublingual extradural intrathecal and transdermal routes. Critics who doubt the usefulness of the term cite the cumbersome American Food and Drug Administration FDA definition of .