Asthma Testing in Pregnancy
The demonstration of a reduced FEV1 or ratio of FEV1 to forced vital capacity (FVC) with a 12% or greater improvement in FEV1 after the administration of inhaled albuterol confirms a diagnosis of asthma in pregnancy. Methacholine testing which is used to confirm bronchial hyperactivity in patients with normal pulmonary function, is contraindicated during pregnancy because of the lack of data on the safety of such testing in pregnant patients.
Inhaled β-agonists and Inhaled SteroidsMany studies have shown no increased perinatal risks (including preeclampsia, preterm birth, low birth weight, and congenital malformations) associated with the use of inhaled β-agonists or inhaled corticosteroids in women who were exposed to these agents. Among the drugs for which reassuring data on use in pregnancy are available, albuterol is the inhaled β-agonist that has been studied most extensively, and budesonide is the most extensively studied inhaled corticosteroid.
Q: What are the risks of using oral corticosteroids for the treatment of asthma during pregnancy?
A: The use of oral corticosteroids among pregnant women with asthma has been associated with increased risks of preeclampsia and prematurity among their offspring, as compared with the use of other asthma medications.
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NEJM 2009 April
2009年4月29日 星期三
H1N1新流感：醫師常見十大Q&A
1. 目前市面上似乎有口罩因被囤積而缺貨的情形，疾管局可否提供作為防疫使用？
答： 依傳染病防治法第二十條規定略以「………醫療機構應充分儲備各項防治傳染病之藥品、器材及防護裝備。」又防疫物資及資源建置實施辦法第六條略以「醫療機構為因應傳染病大流行之隔離需要，應自行預估防治動員三十天所需求之防疫物資安全儲備量………」。依作戰計畫，疫情等級提升至B 級時，醫療機構若有不足時，各醫療(事)機構間可相互支援，再有不足，先向縣市疫情指揮中心提出需求。
2. 請問如何取得抗新型流感藥物克流感或瑞樂沙？
答： 合乎通報、公費藥物使用條件之病患，若該醫療院所若為本局之合約配置點，可以直接在該醫院開立藥物，若非配置點，則可轉院到有配置藥物的醫院或請地方衛生局協助。
3. 通報衛生局，請病人回家等衛生局嗎? 還是先幫忙轉負壓?
答：若調查病例之臨床表現無住院的適應症，可以在通報衛生局及採檢後，開立抗病毒藥物後，配戴口罩並避免搭乘大眾運輸工具回家進行居家隔離並等候檢驗結果，衛生局人員將至個案家中開立居家隔離通知書。如經醫師診療評估認為有住院必要者或經檢驗判定為確定個案者，須依「傳染病防治法」安排住院隔離治療，如有相關疑問，請聯絡所在地衛生局。
4. 採檢部份- 由誰來採？需要做何種防護？
答：採檢原則與Influenza 相同，在負壓或是通風良好處採檢，醫護人員需穿戴完整PPE(隔離衣、手套、N95 口罩、髮帽、護目裝備)，採集鼻咽或咽喉拭子檢體，及血清檢體(須採二次，血量約3ml，急性期(發病第1~5 天)與恢復期[發病第14~15天])。
5. 採檢之檢體要送哪裡？如何送?
答: 送疾病管制局研檢中心昆陽辦公室一樓單一窗口，檢體需要冷藏輸送不可冷凍，並附檢體送驗單。
6. 採檢多久後有結果？
答: 原則上，從檢體送抵該窗口開始計算，6 小時至2 天會有結果。(下午三點前檢體送達，則當天發報告，若三點之後，則隔天會有結果。)
7. 開藥原則? 要不要建議家人預防性用藥? 要不要合併Amantadine? 可以申請
Relenza 嗎?
答：符合調查病例的病人即可投藥，然預防性用藥則限極可能病例或確定病例的密切接觸者。目前疾管局提供的H1N1 公費用藥包括Tamiflu 及Relenza，臨床醫師可以二者擇一來治療病患。至於Amantadine，非公費用藥，不在疾管局的建議範圍之內，使用與否由臨床醫師決定。
8. 臨床醫護人員要如何防護?
答：照護病人時應確實遵守標準防護措施、飛沫傳染防護措施及接觸傳染防護
措施，但因為目前的傳播途徑仍未明確，因此建議直接照護極可能或確定病例的工作人員，於進入病房時應佩戴經過密合測試的拋棄式N95 口罩。若可能發生分泌物飛濺，如：氣管插管、引發氣霧或噴霧治療、誘發痰液的採檢、支氣管鏡檢查、呼吸道痰液的抽吸、氣管造口護理、胸腔物理治療、鼻咽抽吸技術、正壓呼吸器面罩等，應使用護目裝備。
9. 病人來到急診，本院非應變醫院，需要轉診?
答：並沒有規定非應變醫院一定不能收治病患，當疑似病患需要住院，可由指揮官調度床位。但若為確定病例則優先收治在應變醫院。
10. 臨床覺得不像H1N1 新型流感可是有旅遊史，可以讓病人回家嗎？
答：如果臨床上沒有任何症狀，請給予衛教並自主健康管理。
答： 依傳染病防治法第二十條規定略以「………醫療機構應充分儲備各項防治傳染病之藥品、器材及防護裝備。」又防疫物資及資源建置實施辦法第六條略以「醫療機構為因應傳染病大流行之隔離需要，應自行預估防治動員三十天所需求之防疫物資安全儲備量………」。依作戰計畫，疫情等級提升至B 級時，醫療機構若有不足時，各醫療(事)機構間可相互支援，再有不足，先向縣市疫情指揮中心提出需求。
2. 請問如何取得抗新型流感藥物克流感或瑞樂沙？
答： 合乎通報、公費藥物使用條件之病患，若該醫療院所若為本局之合約配置點，可以直接在該醫院開立藥物，若非配置點，則可轉院到有配置藥物的醫院或請地方衛生局協助。
3. 通報衛生局，請病人回家等衛生局嗎? 還是先幫忙轉負壓?
答：若調查病例之臨床表現無住院的適應症，可以在通報衛生局及採檢後，開立抗病毒藥物後，配戴口罩並避免搭乘大眾運輸工具回家進行居家隔離並等候檢驗結果，衛生局人員將至個案家中開立居家隔離通知書。如經醫師診療評估認為有住院必要者或經檢驗判定為確定個案者，須依「傳染病防治法」安排住院隔離治療，如有相關疑問，請聯絡所在地衛生局。
4. 採檢部份- 由誰來採？需要做何種防護？
答：採檢原則與Influenza 相同，在負壓或是通風良好處採檢，醫護人員需穿戴完整PPE(隔離衣、手套、N95 口罩、髮帽、護目裝備)，採集鼻咽或咽喉拭子檢體，及血清檢體(須採二次，血量約3ml，急性期(發病第1~5 天)與恢復期[發病第14~15天])。
5. 採檢之檢體要送哪裡？如何送?
答: 送疾病管制局研檢中心昆陽辦公室一樓單一窗口，檢體需要冷藏輸送不可冷凍，並附檢體送驗單。
6. 採檢多久後有結果？
答: 原則上，從檢體送抵該窗口開始計算，6 小時至2 天會有結果。(下午三點前檢體送達，則當天發報告，若三點之後，則隔天會有結果。)
7. 開藥原則? 要不要建議家人預防性用藥? 要不要合併Amantadine? 可以申請
Relenza 嗎?
答：符合調查病例的病人即可投藥，然預防性用藥則限極可能病例或確定病例的密切接觸者。目前疾管局提供的H1N1 公費用藥包括Tamiflu 及Relenza，臨床醫師可以二者擇一來治療病患。至於Amantadine，非公費用藥，不在疾管局的建議範圍之內，使用與否由臨床醫師決定。
8. 臨床醫護人員要如何防護?
答：照護病人時應確實遵守標準防護措施、飛沫傳染防護措施及接觸傳染防護
措施，但因為目前的傳播途徑仍未明確，因此建議直接照護極可能或確定病例的工作人員，於進入病房時應佩戴經過密合測試的拋棄式N95 口罩。若可能發生分泌物飛濺，如：氣管插管、引發氣霧或噴霧治療、誘發痰液的採檢、支氣管鏡檢查、呼吸道痰液的抽吸、氣管造口護理、胸腔物理治療、鼻咽抽吸技術、正壓呼吸器面罩等，應使用護目裝備。
9. 病人來到急診，本院非應變醫院，需要轉診?
答：並沒有規定非應變醫院一定不能收治病患，當疑似病患需要住院，可由指揮官調度床位。但若為確定病例則優先收治在應變醫院。
10. 臨床覺得不像H1N1 新型流感可是有旅遊史，可以讓病人回家嗎？
答：如果臨床上沒有任何症狀，請給予衛教並自主健康管理。
2009年4月23日 星期四
小兒外傷處理要記得的一些數字
小兒外傷處理要記得的一些數字：
- ETT size (mm) = 4+(age/4)
- ETT fix at length (cm): 3 x ETT size (mm)
- Chest tube size (French) = 4 x ETT size (mm)
- NG tube size (French) = 2 x ETT size (mm)
- Foley size (French) = 2 x ETT size (mm)
- Massive hemothorax = 10 cc/kg or 2 cc/kg/hr x 3~4hr
- CT indication for hematuria: >50 RBC/HPF
- DPL volume = 10 cc/kg
- SBP should > 70+(agex2) mm Hg, normally > 90+(agex2) mm Hg
2009年4月21日 星期二
Intima-media thickness, predictor of cardiovascular risk
Heart attack families
There's growing interest in carotid screening. The intima-media thickness (IMT) is a highly accurate predictor of cardiovascular risk. It can be particularly useful for predicting risk over the next three to 10 years in people aged 40-70, so even if other risk factors are low they can be given a statin and blood pressure lowering treatment. This study, worryingly, found increased carotid IMT in children of parents with premature heart attacks. An editorial warns against medical intervention without further study but says lifestyle advice for the whole family is certainly a good idea.
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There's growing interest in carotid screening. The intima-media thickness (IMT) is a highly accurate predictor of cardiovascular risk. It can be particularly useful for predicting risk over the next three to 10 years in people aged 40-70, so even if other risk factors are low they can be given a statin and blood pressure lowering treatment. This study, worryingly, found increased carotid IMT in children of parents with premature heart attacks. An editorial warns against medical intervention without further study but says lifestyle advice for the whole family is certainly a good idea.
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Source: Heart 2009;95:611-612
Steroids for asthmatic children - how long?
Oral steroids (1 mg/kg prednisolone) work well for children with an acute asthma attack. The question is, what's better, three days or five? The answer, from this study of 201 children, is that three days is as good as five. In both cases, around a third had no asthma symptoms a week after starting treatment.
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Source: Evidence-Based Medicine 2009;14:40
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Source: Evidence-Based Medicine 2009;14:40
2009年4月17日 星期五
No More Blood Cultures
Occult Bacteremia in the Postpneumococcal Vaccine Era: No More Blood Cultures
In a study of some 8000 previously healthy, young febrile children with no apparent source of infection, the rate of true-positive blood cultures was only 0.25%.
For decades, the work-up of febrile young children included blood cultures to rule out occult bacteremia. This study assessed the usefulness of this practice in the era of routine childhood immunization with pneumococcal vaccine. Researchers retrospectively reviewed the charts of 8408 previously healthy children (age range, 3–36 months) who presented to a pediatric emergency department in Phoenix between 2004 and 2007 with fever 39°C, had no apparent source of infection, had blood cultures drawn, and were discharged from the ED.
A pediatric infectious diseases specialist determined that 21 blood cultures were true positives (0.25%); of these, 14 grew Streptococcus pneumoniae. Another 159 positive cultures (1.89%) were determined to be contaminants, yielding a ratio of 7.6 contaminants for every 1 true positive culture.
Comment: Routine vaccination for Haemophilus influenzae and pneumococcus has virtually eradicated occult bacteremia in well-appearing febrile children, and the results of this study suggest that blood cultures should no longer be performed in such patients. The complete blood count also is of questionable usefulness in this patient cohort and should not be ordered. Ill-appearing children, whether febrile or not, still warrant an appropriately directed work-up, which might include blood cultures.
—
For decades, the work-up of febrile young children included blood cultures to rule out occult bacteremia. This study assessed the usefulness of this practice in the era of routine childhood immunization with pneumococcal vaccine. Researchers retrospectively reviewed the charts of 8408 previously healthy children (age range, 3–36 months) who presented to a pediatric emergency department in Phoenix between 2004 and 2007 with fever 39°C, had no apparent source of infection, had blood cultures drawn, and were discharged from the ED.
A pediatric infectious diseases specialist determined that 21 blood cultures were true positives (0.25%); of these, 14 grew Streptococcus pneumoniae. Another 159 positive cultures (1.89%) were determined to be contaminants, yielding a ratio of 7.6 contaminants for every 1 true positive culture.
Comment: Routine vaccination for Haemophilus influenzae and pneumococcus has virtually eradicated occult bacteremia in well-appearing febrile children, and the results of this study suggest that blood cultures should no longer be performed in such patients. The complete blood count also is of questionable usefulness in this patient cohort and should not be ordered. Ill-appearing children, whether febrile or not, still warrant an appropriately directed work-up, which might include blood cultures.
—
Diane M. Birnbaumer, MD, FACEP
Published in Journal Watch Emergency Medicine April 17, 2009
Citation(s): Wilkinson M et al. Prevalence of occult bacteremia in children aged 3 to 36 months presenting to the emergency department with fever in the postpneumococcal conjugate vaccine era. Acad Emerg Med 2009 Mar; 16:220.
Published in Journal Watch Emergency Medicine April 17, 2009
Citation(s): Wilkinson M et al. Prevalence of occult bacteremia in children aged 3 to 36 months presenting to the emergency department with fever in the postpneumococcal conjugate vaccine era. Acad Emerg Med 2009 Mar; 16:220.
2009年4月13日 星期一
2009年4月11日 星期六
Simple DKA 治療有三大禁忌
Simple DKA 治療有三大禁忌 (尤其是小於20y者)！
因為治療的最佳 end-point 是 AG (anion gap)！
And, sugar 小於250 就要馬上換上糖水 + insulin。
- 不能開始就用 hypotonic solution 來 challenge (即使有 hypernatremia)！
- 不能用 Jusomine (即使 pH小於7.2)！
- 不能使 blood sugar 降太快 (每小時下降不可大於100mg/dL)！
因為治療的最佳 end-point 是 AG (anion gap)！
And, sugar 小於250 就要馬上換上糖水 + insulin。
2009年4月10日 星期五
懷疑 appendicitis？先做超音波
Diagnosing Acute Appendicitis in Adults: Accuracy of Color Doppler Sonography and MDCT Compared with Surgery and Clinical Follow-Up
OBJECTIVE. The objective of our study was to evaluate the accuracy of color Doppler sonography and contrast-enhanced MDCT in the diagnosis of acute appendicitis in adults and their utility as a triage tool in lower abdominal pain.
MATERIALS AND METHODS. We reviewed the medical records of 420 consecutive adult patients, 271 women and 149 men, 18 years old or older, referred from the emergency department to sonography examination for clinically suspected acute appendicitis between January 2003 and June 2006. Patients underwent sonography of the right upper abdomen and pelvis followed by graded compression and color Doppler sonography of the right lower quadrant. CT was performed in 132 patients due to inconclusive sonography findings or a discrepancy between the clinical diagnosis and the sonography diagnosis. Sonography and CT reports were compared with surgery or clinical follow-up as the reference standard. Statistical analyses were performed by Pearson's chi-square test and cross-tabulation software.
RESULTS. Sonography and CT correctly diagnosed acute appendicitis in 66 of 75 patients and in 38 of 39 patients, respectively, and correctly denied acute appendicitis in 312 of 326 and in 92 of 92 patients. Sonography was inconclusive in 17 of 418 cases and CT, in one of 132 cases. Sonography and CT allowed alternative diagnoses in 82 and 42 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for sonography were 74.2%, 97%, 88%, 93%, and 92%, respectively, and for CT, 100%, 98.9%, 97.4%, 100%, and 99%.
CONCLUSION. Sonography should be the first imaging technique in adult patients for the diagnosis of acute appendicitis and triage of acute abdominal pain. CT should be used as a complementary study for selected cases.
AJR 2008; 190:1300-1306
OBJECTIVE. The objective of our study was to evaluate the accuracy of color Doppler sonography and contrast-enhanced MDCT in the diagnosis of acute appendicitis in adults and their utility as a triage tool in lower abdominal pain.
MATERIALS AND METHODS. We reviewed the medical records of 420 consecutive adult patients, 271 women and 149 men, 18 years old or older, referred from the emergency department to sonography examination for clinically suspected acute appendicitis between January 2003 and June 2006. Patients underwent sonography of the right upper abdomen and pelvis followed by graded compression and color Doppler sonography of the right lower quadrant. CT was performed in 132 patients due to inconclusive sonography findings or a discrepancy between the clinical diagnosis and the sonography diagnosis. Sonography and CT reports were compared with surgery or clinical follow-up as the reference standard. Statistical analyses were performed by Pearson's chi-square test and cross-tabulation software.
RESULTS. Sonography and CT correctly diagnosed acute appendicitis in 66 of 75 patients and in 38 of 39 patients, respectively, and correctly denied acute appendicitis in 312 of 326 and in 92 of 92 patients. Sonography was inconclusive in 17 of 418 cases and CT, in one of 132 cases. Sonography and CT allowed alternative diagnoses in 82 and 42 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for sonography were 74.2%, 97%, 88%, 93%, and 92%, respectively, and for CT, 100%, 98.9%, 97.4%, 100%, and 99%.
CONCLUSION. Sonography should be the first imaging technique in adult patients for the diagnosis of acute appendicitis and triage of acute abdominal pain. CT should be used as a complementary study for selected cases.
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The study of 420 medical records found that sonography correctly denied acute appendicitis in 303 of 312 adult patients, meaning it had a 97% specificity rate, said Diana Gaitini, MD, of Rambam Health Care Campus in Haifa, Israel. "When the patient does not have acute appendicitis, the negative result of the color Doppler ultrasound examination is highly confident," she said. On the other hand, ultrasound's sensitivity rate was 74%, meaning it missed the diagnosis in 23 of 89 patients, Dr. Gaitini said. Ultrasound was inconclusive in 17 patients.
"We performed CT in 132 patients because the ultrasound examination was inconclusive or the patient was showing classical signs and symptoms of acute appendicitis even though the ultrasound examination was negative," said Dr. Gaitini. CT correctly diagnosed acute appendicitis in 38 of 39 patients (99% sensitivity rate) and correctly denied acute appendicitis in all 92 patients (100% specificity rate), said Dr. Gaitini. CT was inconclusive in one patient.
"CT has a slightly higher specificity rate and a higher sensitivity rate than ultrasound, but ultrasound can help the radiologist make a definitive diagnosis in most patients," Dr. Gaitini said. "The higher diagnostic performances of CT need to be evaluated against its disadvantages. Lack of radiation exposure (which is especially important in a population of mostly young patients), higher availability, lower cost and high specificity of color Doppler ultrasound are the main reasons for trying ultrasound first," she said.
The study appears in the May issue of the American Journal of Roentgenology.
如何簡單決定現場停止CPR？
Validation of a universal prehospital termination of resuscitation clinical prediction rule for advanced and basic life support providers
Resuscitation
Volume 80, Issue 3, March 2009, Pages 324-328
Prehospital termination of resuscitation rules have been derived for Emergency Medical Technician-Paramedics providing advanced life support care and defibrillation-only Emergency Medical Technicians providing basic life support care. We sought to externally validate each rule on a prospective cohort of prehospital cardiac arrest patients to determine if either rule could be proposed as a universal prehospital termination of resuscitation rule.
Methods
Investigators at the University of Toronto performed a secondary cohort analysis of data prospectively collected for the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest trial from 1 April 2006 to 1 April 2007 by one site. The diagnostic test characteristics and predicted transportation rate were calculated for each rule.
Results
Of the 2415 patients with cardiac arrest of presumed cardiac etiology, the advanced life support rule recommended termination of resuscitation for 743 patients. No survivors were identified in this group. It had a specificity of 100% for recommending transport of potential survivors, a positive predictive value of 100% for death and a predicted transport rate of 69%. The basic life support rule recommended termination of resuscitation for 1302 patients, with no survivors. This rule had a specificity of 100%, a positive predictive value of 100% and a predicted transport rate of 46%.
Conclusions
Implementing the basic life support rule as a universal termination of resuscitation clinical prediction rule would result in a lower overall transport rate without missing any potential survivors. The universal rule would recommend termination of resuscitation when there was no return of spontaneous circulation prior to transport, no shock was given and the arrest was not witnessed by Emergency Medical Services personnel. This rule may be useful for emergency medical services systems with mixed levels of providers responding to cardiac arrest patients.
Resuscitation
Volume 80, Issue 3, March 2009, Pages 324-328
Prehospital termination of resuscitation rules have been derived for Emergency Medical Technician-Paramedics providing advanced life support care and defibrillation-only Emergency Medical Technicians providing basic life support care. We sought to externally validate each rule on a prospective cohort of prehospital cardiac arrest patients to determine if either rule could be proposed as a universal prehospital termination of resuscitation rule.
Methods
Investigators at the University of Toronto performed a secondary cohort analysis of data prospectively collected for the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest trial from 1 April 2006 to 1 April 2007 by one site. The diagnostic test characteristics and predicted transportation rate were calculated for each rule.
Results
Of the 2415 patients with cardiac arrest of presumed cardiac etiology, the advanced life support rule recommended termination of resuscitation for 743 patients. No survivors were identified in this group. It had a specificity of 100% for recommending transport of potential survivors, a positive predictive value of 100% for death and a predicted transport rate of 69%. The basic life support rule recommended termination of resuscitation for 1302 patients, with no survivors. This rule had a specificity of 100%, a positive predictive value of 100% and a predicted transport rate of 46%.
Conclusions
Implementing the basic life support rule as a universal termination of resuscitation clinical prediction rule would result in a lower overall transport rate without missing any potential survivors. The universal rule would recommend termination of resuscitation when there was no return of spontaneous circulation prior to transport, no shock was given and the arrest was not witnessed by Emergency Medical Services personnel. This rule may be useful for emergency medical services systems with mixed levels of providers responding to cardiac arrest patients.
2009年4月8日 星期三
Reflux and Asthma
Gastroesphageal Reflux and Asthma
There is a high prevalence of asymptomatic gastroesophageal reflux among patients with asthma. Esophageal pH-monitoring studies have shown that 32 to 84% of persons with asthma have abnormal acid reflux. About half of those patients with asthma who have reflux have no symptoms. Symptoms of asthma — cough and chest discomfort — may overlap with those of gastroesophageal reflux, making it difficult to distinguish between the two.
Pathophysiology of Reflux and Asthma
The causal relationship between asthma and gastroesophageal reflux is complex. Acid reflux causes bronchoconstriction through microaspiration into the airways, as well as through reflex-mediated effects of acid on the esophagus or upper airway. Asthma-related bronchoconstriction can induce acid reflux. Descent of the diaphragm with hyperinflation increases the pressure gradient between the abdomen and thorax and may cause the barrier function of the lower esophageal sphincter to diminish. Drugs used to control asthma, including beta-agonists and methyxanthine bronchodilators, may decrease the tone of the lower esophageal sphincter.
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New England Journal of Medicine - Vol. 360, No. 15, April 9, 2009
There is a high prevalence of asymptomatic gastroesophageal reflux among patients with asthma. Esophageal pH-monitoring studies have shown that 32 to 84% of persons with asthma have abnormal acid reflux. About half of those patients with asthma who have reflux have no symptoms. Symptoms of asthma — cough and chest discomfort — may overlap with those of gastroesophageal reflux, making it difficult to distinguish between the two.
Pathophysiology of Reflux and Asthma
The causal relationship between asthma and gastroesophageal reflux is complex. Acid reflux causes bronchoconstriction through microaspiration into the airways, as well as through reflex-mediated effects of acid on the esophagus or upper airway. Asthma-related bronchoconstriction can induce acid reflux. Descent of the diaphragm with hyperinflation increases the pressure gradient between the abdomen and thorax and may cause the barrier function of the lower esophageal sphincter to diminish. Drugs used to control asthma, including beta-agonists and methyxanthine bronchodilators, may decrease the tone of the lower esophageal sphincter.
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New England Journal of Medicine - Vol. 360, No. 15, April 9, 2009
Myocarditis
Myocarditis may present with a wide range of symptoms, ranging from mild dyspnea or chest pain that resolves without specific therapy to cardiogenic shock and death. Dilated cardiomyopathy with chronic heart failure is the major long-term sequela of myocarditis. Most often, myocarditis results from common viral infections; less commonly, myocarditis may result from other pathogens, toxic or hypersensitivity drug reactions, giant-cell myocarditis, or sarcoidosis. Cardiac MRI is increasingly used as a diagnostic test in suspected acute myocarditis, and may be used to localize sites for endomyocardial biopsy.
Clinical Pearl Biomarkers and Myocarditis
Biomarkers of cardiac injury are elevated in a minority of patients with acute myocarditis but, if present, may help confirm the diagnosis. Troponin I has high specificity (89%) but limited sensitivity (34%) in the diagnosis of myocarditis. Clinical and experimental data suggest that increased levels of cardiac troponin I are more common than increased levels of creatinine kinase MB in acute myocarditis.
Clinical Pearl Causes of Myocarditis
Viral and postviral myocarditis remain the major causes of acute and chronic dilated cardiomyopathy; viruses associated with myocarditis include coxsackievirus B, adenovirus, parvovirus B19, Epstein–Barr virus, cytomegalovirus, and human herpesvirus 6. Other infectious causes of myocarditis include Borrelia burgdorferi (Lyme disease), with or without coinfection of ehrlichia or babesia, and Trypanosoma cruzi infection. Numerous medications including some anticonvulsants, antibiotics, and antipsychotics, have been implicated in hypersensitivity myocarditis. Eosinophilic myocarditis may occur in association with Churg–Strauss syndrome, Löffler's endomyocardial fibrosis, cancer, parasitic, helminthic, or protozoal infections.
How helpful is an EKG in diagnosing myocarditis and what kinds of EKG changes might you see in a patient with myocarditis?
A: The sensitivity of the electrocardiogram for myocarditis is low (47%). In a patient with acute myocarditis, the electrocardiogram may show sinus tachycardia with nonspecific ST-segment and T-wave abnormalities. Occasionally, the changes on electrocardiography are suggestive of an acute myocardial infarction and may include ST-segment elevation, ST-segment depression, and pathologic Q waves. Pericarditis not infrequently accompanies myocarditis clinically and is often manifested in pericarditis-like changes seen on electrocardiography.
When should endomyocardial biopsy be performed?
A: Endomyocardial biopsy should be performed in patients with unexplained, new-onset heart failure of less than 2 weeks' duration in association with a normal-size or dilated left ventricle and hemodynamic compromise, for suspected fulminant myocarditis. Endomyocardial biopsy should also be performed in patients with unexplained, new-onset heart failure of 2 weeks' to 3 months' duration in association with a dilated left ventricle and new ventricular arrhythmias or Mobitz type II or second-degree or third-degree heart block in patients who do not have a response to usual care within 1 to 2 weeks, for suspected giant-cell myocarditis. (Cooper et al., Circulation, 2007.)
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New England Journal of Medicine - Vol. 360, No. 15, April 9, 2009
Clinical Pearl Biomarkers and Myocarditis
Biomarkers of cardiac injury are elevated in a minority of patients with acute myocarditis but, if present, may help confirm the diagnosis. Troponin I has high specificity (89%) but limited sensitivity (34%) in the diagnosis of myocarditis. Clinical and experimental data suggest that increased levels of cardiac troponin I are more common than increased levels of creatinine kinase MB in acute myocarditis.
Clinical Pearl Causes of Myocarditis
Viral and postviral myocarditis remain the major causes of acute and chronic dilated cardiomyopathy; viruses associated with myocarditis include coxsackievirus B, adenovirus, parvovirus B19, Epstein–Barr virus, cytomegalovirus, and human herpesvirus 6. Other infectious causes of myocarditis include Borrelia burgdorferi (Lyme disease), with or without coinfection of ehrlichia or babesia, and Trypanosoma cruzi infection. Numerous medications including some anticonvulsants, antibiotics, and antipsychotics, have been implicated in hypersensitivity myocarditis. Eosinophilic myocarditis may occur in association with Churg–Strauss syndrome, Löffler's endomyocardial fibrosis, cancer, parasitic, helminthic, or protozoal infections.
How helpful is an EKG in diagnosing myocarditis and what kinds of EKG changes might you see in a patient with myocarditis?
A: The sensitivity of the electrocardiogram for myocarditis is low (47%). In a patient with acute myocarditis, the electrocardiogram may show sinus tachycardia with nonspecific ST-segment and T-wave abnormalities. Occasionally, the changes on electrocardiography are suggestive of an acute myocardial infarction and may include ST-segment elevation, ST-segment depression, and pathologic Q waves. Pericarditis not infrequently accompanies myocarditis clinically and is often manifested in pericarditis-like changes seen on electrocardiography.
When should endomyocardial biopsy be performed?
A: Endomyocardial biopsy should be performed in patients with unexplained, new-onset heart failure of less than 2 weeks' duration in association with a normal-size or dilated left ventricle and hemodynamic compromise, for suspected fulminant myocarditis. Endomyocardial biopsy should also be performed in patients with unexplained, new-onset heart failure of 2 weeks' to 3 months' duration in association with a dilated left ventricle and new ventricular arrhythmias or Mobitz type II or second-degree or third-degree heart block in patients who do not have a response to usual care within 1 to 2 weeks, for suspected giant-cell myocarditis. (Cooper et al., Circulation, 2007.)
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New England Journal of Medicine - Vol. 360, No. 15, April 9, 2009
2009年4月3日 星期五
AED在IHCA幫助不大？！
AEDs Do Not Improve Survival from In-Hospital Arrest
During the year after one hospital switched from standard to automated external defibrillators, overall survival from in-hospital cardiac arrest dropped from 23% during the previous year to 18%.
Use of automated external defibrillators (AEDs) in the out-of-hospital setting saves lives, and a recent study suggested a survival benefit from use of AEDs in hospitals. Investigators compared time to first shock and survival rates from cardiac arrest at a large teaching hospital in Michigan during the year before and after standard monophasic external defibrillators were replaced with biphasic AEDs.
No differences in predominant rhythm or medical comorbidities were noted between the 277 patients in the standard-defibrillator group and the 284 patients in the AED group. After the switch to AEDs, rates of survival to discharge did not change significantly in patients with ventricular fibrillation or tachycardia (29% before and 31% after) but declined significantly in patients with initial asystole or pulseless electrical activity (from 23% to 15%). Time to first shock did not differ between the two periods.
Comment:
AEDs save lives when deployed appropriately in the outpatient setting. This study is not the first to dampen enthusiasm for AED use in other settings: One study showed that AED use in the home did not improve survival in patients with prior anterior myocardial infarction who were not candidates for implantable defibrillators (JW Emerg Med Apr 11 2008). Pausing cardiopulmonary resuscitation (CPR) to apply AED pads might not be beneficial in the hospital, where arrests are less often caused by "shockable" rhythms (ventricular fibrillation and pulseless ventricular tachycardia) than they are outside the hospital. Alternatively, performance of standard defibrillators might be so good that AEDs do not save additional time. For now, the emphasis in the hospital should be on an organized, rapid response with early CPR and defibrillation, either by AED or standard defibrillator.
—
Daniel J. Pallin, MD, MPH
Published in Journal Watch Emergency Medicine April 3, 2009
Forcina MS et al. Cardiac arrest survival after implementation of automated external defibrillator technology in the in-hospital setting. Crit Care Med 2009 Apr; 37:1229.
During the year after one hospital switched from standard to automated external defibrillators, overall survival from in-hospital cardiac arrest dropped from 23% during the previous year to 18%.
Use of automated external defibrillators (AEDs) in the out-of-hospital setting saves lives, and a recent study suggested a survival benefit from use of AEDs in hospitals. Investigators compared time to first shock and survival rates from cardiac arrest at a large teaching hospital in Michigan during the year before and after standard monophasic external defibrillators were replaced with biphasic AEDs.
No differences in predominant rhythm or medical comorbidities were noted between the 277 patients in the standard-defibrillator group and the 284 patients in the AED group. After the switch to AEDs, rates of survival to discharge did not change significantly in patients with ventricular fibrillation or tachycardia (29% before and 31% after) but declined significantly in patients with initial asystole or pulseless electrical activity (from 23% to 15%). Time to first shock did not differ between the two periods.
Comment:
AEDs save lives when deployed appropriately in the outpatient setting. This study is not the first to dampen enthusiasm for AED use in other settings: One study showed that AED use in the home did not improve survival in patients with prior anterior myocardial infarction who were not candidates for implantable defibrillators (JW Emerg Med Apr 11 2008). Pausing cardiopulmonary resuscitation (CPR) to apply AED pads might not be beneficial in the hospital, where arrests are less often caused by "shockable" rhythms (ventricular fibrillation and pulseless ventricular tachycardia) than they are outside the hospital. Alternatively, performance of standard defibrillators might be so good that AEDs do not save additional time. For now, the emphasis in the hospital should be on an organized, rapid response with early CPR and defibrillation, either by AED or standard defibrillator.
—
Daniel J. Pallin, MD, MPH
Published in Journal Watch Emergency Medicine April 3, 2009
Forcina MS et al. Cardiac arrest survival after implementation of automated external defibrillator technology in the in-hospital setting. Crit Care Med 2009 Apr; 37:1229.
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