精品外科实证医学课程

1、外科實證醫學課程,Somatostatin Analogues for Acute Bleeding Esophageal Varices,外科 莊世昌 醫師,執行EBM的五個步驟 ( I ),1.問問題（可以回答的問題） Converting the need for information into an answerable question. 2.找資料（可獲得最好的證據資訊） Search the database and tracking down the best evidence. 3.分析判斷（文獻的效度與重要性） Critical appraising that evidence for its validity and importance.,執行EBM的五個步驟 ( II ),4.臨床應用（整合三大層面） Integrating the critical appraising with our clinical expertise and our patients unique biology, values and circumstances. 5.評估成果（

2、執行EBM的效率） Evaluating our effectiveness and efficiency in executing step 1- 4 and seeking ways to improve them both for next time.,Case,王xx 56 y/o male Hepatitis B Hx for 20+ years Liver cirrhosis since 3+ years UGI bleeding 2 episodes = Gastroendoscope: EV bleeding Admission due to 3rd GI bleeding,Background Knowledge,Portal pressure (5-8mmHg) Esophagogastric varices : coronary & short gastric v. to azygos v. Caput medusae : epigastric v. Retroperitoneal callateral vessels Hemorrhoid venous plex

3、us Intrahepatic shunts,Portal Vein Physiology,Esophageal Varices,A. Noninterventional 1. Vasopressin, terlipressin 2. Somatostatin 3. Balloon tamponade B. Interventionsal, nonsurgical 4. Endoscopic sclerotherapy 5. Endoscopic ligation C. Surgical 6. Emergency portasystemic shunts 7. Esophageal transection and reanastomosis 8. Esophagogastric devascularization 9. Suture ligation of varices,Treatment,Medications,Vasopressin (血管加壓素) Terlipressin Somatostatin (體抑素) Octreotide,Octreotide,Sandostatin

4、0.1mg/1ml/Amp Long-acting somatostatin analog 降低奇靜脈血流 半衰期: 90 min IV bolus 50-250 ug, continuous 50-250 ug/h Side effects: hyper or hypoglycemia, Abd. pain, nausea, diarrhea, headache,Objectives,To study whether somatostatin or analogues improve survival or reduce the need for blood transfusions in patients with bleeding oesophageal varices.,How to Ask Clinical Question You Can Answer?,問題以PICO形式呈現,搜 尋 技 巧 與 策 略,資料庫的選擇 關鍵字的設定 學習各種資料庫的搜尋方法 圖書館定期開課,Step2 :Search Data for evidence,常用實證醫學電子資源,Critica

5、l appraisal 文獻的分析判斷,文獻的結果是否有可信度？ (Validity) 文獻的結果是否有重要性？ (Importance) 此資料如何運用於臨床工作?(Practice) 文獻的分析判斷前需先分類，不同種類的文獻，研究方法不同，評判方式也有異。 最常見的四類文獻：Therapy, Harm, Diagnosis, Prognosis,Step 3,Diagnostic study important,Sensitivity Specificity Likelihood ratio for a positive test result Likelihood ratio for a negative test result Positive predictive value Negative predictive value Pre-test probability (prevalence) Pre-test odds = prevalence/(1-prevalence) Post-test odds = pre-test odds LR,Therapeutic stud

6、y important,Control event rate (CER) Experimental event rate (EER) Relative risk reduction (RRR) Absolute risk reduction (ARR) Number needed to treat (NNT),The Evidence Pyramid,Levels of Evidence and Grades of Recommendations,Seach Result,Cochrane標誌及其意義,Cochrane協作網標誌（見圖）由一個圓形圖以及圍繞圓形圖的兩個粗體同心半環圖共同構成。 每一橫線代表一個試驗結果的可信區間，橫線越短則試驗精度越高，結果越肯定 垂直線（代表OR=1）將圓一分為二，可用於判斷結果差別有無統計學意義，以區別治療效果，一般來說具有療效的試驗結果分佈於垂直線左側;若橫線落在垂直線右側,則表明治療結果無效。 橫線與垂直線相接觸或相交，則表明該RCT中的不同治療措施間差異無統計學意義。 圓形圖內下方的菱形符號代表7個RCT的綜合結果。符號位於左邊表明治療措施有效

7、，位於右邊則表明治療措施弊大於利。,該圓形圖展示了一項短程價廉的激素類藥物 Hydrocortisone治療可能早產的孕婦療效的隨 機對照試驗系統評價結果。第一個試驗於1972 年報導。至1991年，另外6項試驗結果也相繼報導，但7個試驗結果不一致，該療法是否利大於害，根據單個的臨床試驗結果難以確定。而系統評價結果明確肯定：Hydrocortisone的確可降低新生兒死於早產併發症的危險，使早產兒死亡率下降30%-50%。直至1989年，由於沒有進行相關的系統評價分析和報導，多數產科醫師並未認識到該項治療措施的效果,成千上萬的早產兒可能因其母親未接受相應治療而死亡（還耗費更多不必要的治療費用）。在臨床醫學中,由於未能根據RCTs製作出及時的、不斷更新的系統評價而導致以生命為代價的這類例子，不勝枚舉。,Seach Strategy,MEDLINE (PubMed) from 1966 to Feb 2004 Key word: (somatostatin or octreotide or vapreotide or lanreotide) combined with (varic* or

8、 bleed* or hemorrhag* or hematemesis or melena) The Cochrane library Key word: (somatostatin explode all trees (mesh) or somatostatin* or octreotide or vapreotide or lanreotide) and (varic* or bleed* or hemorrhag* or hematemesis or melena ),Selection Criteria,All randomised trials comparing somatostatin or analogues with placebo or no treatment in patients suspected of acute or recent bleeding from oesophageal varices.,Description of Studies,Included 20 trials (2518 patients, average of about 10

9、0 patients per trial) The dose schedules and length of treatment were quite variable,Methodological Quality,Double-blind: nine trials Blinding during data analysis: four trials All or nearly all (90%) of the randomised patients in the analysis: seven trials In four trials, some of the randomised patients were excluded because the source of bleeding was judged to be non-variceal In the remaining trials it was not clear whether there had been additional patients that were not accounted for.,The trials were divided in two groups High-quality group: the allocation of patients to treatment groups had to be concealed and the trials had to be double-blind Low-quality group,Types of Outcome Measures,Mortality. Number of blood transfusions. Number with balloon tamponade. Number failing initial haemostasis. Number with rebleeding.,Results (1),The drugs did not reduce mortality signicantly Relative risk 0.96 (95% condence interval (CI) 0.74 to 1.24) for the high-quality trials 0.79

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