External noninvasive cardiac pacing in out-of-hospital cardiac arrest

External noninvasive cardiac pacing was applied outside the hospital to 19 patients who had experienced cardiopulmonary arrest and 1 patient with life-threatening bradycardia. Seven patients developed electrocardiographic evidence of pacemaker capture, although only 2 had palpable pulses. The patient with bradycardia was successfully paced. This study demonstrates the feasibility of cardiac pacing in out-of-hospital cardiac arrest but confirms the poor prognosis of asystolic cardiac arrest even with the application of pacing.     

Utility of cardiac troponin measurement after cardiac surgery

Postoperative cardiac failure due to myocardial necrosis remains a major complication in cardiac surgical procedures and its diagnosis is still difficult. In fact, cardiac enzymes, electrocardiogram and echographic signs are often misleading. The prognostic valve of troponin I after coronary artery bypass or conventional value surgery has been evaluated in 500 adult patients. Postoperative troponin I concentrations after cardiac surgery represent an independent variable associated with mortality (in-hospital death) and morbidity (low cardiac output and acute renal failure).     

Spontaneous gasping generates cardiac output during cardiac arrest

OBJECTIVES: To measure stroke volumes coincident with spontaneous gasping during untreated ventricular fibrillation and to evaluate the effects of gasping. DESIGN: Prospective study in laboratory animals. SETTING: University-affiliated research institute. SUBJECTS: Male Yorkshire-X domestic pigs. INTERVENTIONS: Pigs were anesthetized (ketamine, 20 mg/kg intramuscularly and sodium pentobarbital, 30 mg/kg intravenously), intubated, and mechanically ventilated. Ventricular fibrillation was electrically induced and untreated for 7 mins. The right femoral artery and vein were cannulated. A 5.5/7.5-MHz biplanar transesophageal echocardiography transducer was advanced into the esophagus. MEASUREMENTS AND MAIN RESULTS: Stroke volumes were measured as the product of the transaortic blood flow velocity and transesophageal echocardiographic measurements of valve area. In addition, left ventricular volumes were echocardiographically estimated at peak inspiration and at peak expiration of each gasp by transesophageal methods. The stroke volume produced by gasping averaged 23 +/- 6 mL, which represented approximately 60% of a precardiac arrest stroke volume (38 +/- 8 mL, p <.001). Increases in end-tidal carbon dioxide tension coincident with each gasp were consistent with comparable increases in pulmonary blood flow and therefore stroke volumes. Both were associated with increases in aortic pressure from 20 +/- 3 to 33 +/- 8 mm Hg (p <.001) and coronary perfusion pressure from 4 +/- 3 to 13 +/- 7 mm Hg (p <.001). CONCLUSIONS: Our studies confirm that preterminal gasping during ventricular fibrillation increases both ventilation and forward blood flow.     

心脏介入术中并发急性心脏压塞的抢救与护理

目的研究心脏介入术(CIO)中并发急性心脏压塞(ACT)的抢救与护理。方法将64例患者实施CIO时并发ACT,以数字法随机分成观察组及对照组各32例,2组均实施ACT抢救措施,对照组在此基础上另实施常规护理,而观察组则实施综合护理。对比2组ACT发现率及抢救成功率,2组护理满意情况以及HDL评分情况。结果观察组ACT发现率及抢救成功率均显著高于对照组,差异均有统计学意义(P0.05);观察组的护理满意情况显著优于对照组,差异有统计学意义(P0.05);观察组护理后的焦虑、抑郁评分及总分均显著低于护理前及对照组,差异有统计学意义(P0.05)。结论对CIO并发ACT患者,积极予以抢救措施及综合护理,可明显提升抢救成功率及护理满意率,降低HDL评分,减少医患纠纷。     

Non-invasive cardiac mapping for non-response in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an effective intervention in selected patients with moderate-to-severe heart failure with reduced ejection fraction and abnormal left ventricular activation time. The non-response rate of approximately 30% has remained nearly unchanged since this therapy was introduced 25 years ago. While intracardiac mapping is widely used for diagnosis and guidance of therapy in patients with tachyarrhythmia, its application in characterization of the electrical substrate to elucidate the mechanisms involved in CRT response remain anecdotal. In the present review, we describe the traditional determinants of CRT response before presenting novel non-invasive techniques used for CRT optimization. We discuss efforts to identify the target electrical substrate to guide the deployment of pacing electrodes during the operative procedure. Non-invasive body surface mapping technologies such as ECG imaging or ECG belt enables prediction of acute and chronic CRT response. While electrical dyssynchrony parameters provide high predictive accuracy for CRT response when obtained during intrinsic conduction, their predictive value is less when acquired during CRT or LV-pacing.

Key messages

• Classic predictors of CRT response are female gender, NYHA class ≤ III, left ventricular ejection fraction ≥25%, QRS duration ≥150 ms and estimated glomerular filtration rate ≥60 mL/min.
• ECG-imaging is a comprehensive non-invasive mapping system which allows to express the amount of electrical asynchrony of a CRT candidate.
• Non-invasive body surface mapping technologies enables excellent prediction of acute and chronic CRT response before implantation.
• When performed during CRT or LV-pacing, the added value of these mapping systems remains unclear.

     

Continuous Fick cardiac output compared to thermodilution cardiac output

A system has been developed to monitor continuously the components of the oxygen Fick equation: oxygen consumption by a gas exchange analyzer and arteriovenous oxygen difference by pulse and fiberoptic oximetry. A computer-based system was developed which calculates cardiac output and other variables every 20 sec. Continuous Fick (CF) cardiac output was compared to thermodilution (TD) cardiac output in 21 ventilated post-cardiac surgery patients. A total of 237 simultaneous cardiac output measurements had a range between 2 and 11 L/min. The correlation between CF and TD cardiac outputs was r = .86, with an equation of TD cardiac output = 0.92 CF cardiac output + 1.16. There was a significant (p less than .001) difference between the two methods of cardiac output estimation. The CF method was consistently lower than TD; this difference was greater at lower flows. CF cardiac output measurement is practical; it offers distinct advantages in viewing cardiac output together with oxygen demand and oxygen extraction.     

Cardiopulmonary resuscitation. Detecting cardiac arrhythmias in cardiac arrest

This article weighs the evidence for and against giving women in labour the choice of whether or not to eat and drink. While in the 1940s UK midwives were advised not to offer women such a choice, current research has swung in the opposite direction.     

注射用复合辅酶预处理对心脏病人非心脏手术的心肌钙蛋白与心肌酶学的影响

目的 观察注射用复合辅酶（贝科能）对心脏病人非心脏手术围手术期的心肌酶谱和心肌钙蛋白的变化,从而研究贝科能的心脏保护作用。方法30例心脏病人非心脏手术即全麻下行单纯胆囊切除术的病人,美国麻醉医师协会（ASA）分级Ⅱ-Ⅲ级,随机双盲分成A、B两组,分别静滴贝科能和生理盐水,然后常规诱导。监测心电图（ECG）,心率（HR）,血压（BP）。分别于入室后（T0）,手术开始1h（T1）,术后8h（T2）,术后24h（T3）采集血液2．5ml,定量测定心肌钙蛋白T（cTnI）,及肌酸激酶（CK）和肌酸激酶同工酶（CK—MB）。结果 A组病人cTnI、CK及CK—MB在术后8h及术后24h结果与入室后结果对比均增高（P〈0．05）有显著差异。B组病人cTnI、CK及CK—MB在术后1h,术后8h及术后4h与入室后结果对比均增高（P〈0．05）,有显著差异,其中cTnI在术后8h及24h的结果与入室后对比有非常显著差异（P〈0．01）。与A组病人对比,术后1 h、8 h及24 h的cTnI与A组比较有非常显著差异（P〈0．01）,CK及CK—MB与A组比较有显著差异（P〈0．05）。结论 贝科能能减轻心肌损害,降低心脏病人术后心肌缺血以致心血管意外的发生率,在围术期应用有一定的临床意义。     

Circulating cardiac troponin I in trauma patients without cardiac contusion

Objectives: To describe the evolution and the diagnostic value of cardiac troponin I (cTnI) and to relate its concentrations with the indicators of injury in trauma patients. Design: Prospective, observational study of 17 young, previously healthy, mechanically-ventilated patients during the early post-traumatic period in the Surgical ICU of a University Hospital. Methods: Serial measurements of serum cTnI, total creatine kinase activity (CKtot) and its isoenzyme MB (CK-MB) (on admission, 12 h later, then daily for 7 days), clinical data and repeated electrocardiographic (ECG) and transesophageal echocardiographic (TEE) recordings. Results: Rhabdomyolysis was observed in all the patients with a significant relationship between CK-MB and CKtot. Despite the fact that no patient demonstrated ECG or TEE signs of myocardial contusion, elevated serum levels of cTnI were observed in six patients (35 %) without obvious dilutional interference. As compared with the others, these patients exhibited a more frequent arterial hypotension (83 % vs 18 %, p = 0.035), required greater volume expansion on day 1 (22,000 vs 8,500 ml, p = 0.027) and usually demonstrated early (83 % vs 9 %, p = 0.005) and late (66 % vs 9 %, p = 0.028) multiple organ dysfunction syndrome. Conclusions: Taking into account the high reported sensitivity and specificity of cTnI dosage, the present results suggest cTnI can play a role in the evaluation of indirect myocardial injury following traumatic shock. Received: 20 November 1997 Accepted: 3 March 1998     

Open versus closed chest cardiac massage in non-traumatic cardiac arrest

Since the rediscovery and popularization of closed-chest cardiopulmonary resuscitation (CPR) in the early 1960s, this technique has largely replaced open-chest cardiac massage. However, in the ensuing quarter of a century, a large amount of data has been accumulated that seems to indicate that open-chest CPR is the physiologically superior method of cardiopulmonary resuscitation. This paper reviews that data comparing these two CPR modalities. The first part discusses data obtained from animal studies, while the second considers the limited amount of information that has been obtained from human investigations. The authors concludes that a randomized clinical trial of open-chest and closed-chest CPR is needed to fully evaluate the efficacy of these two resuscitative techniques as well as to define the most appropriate circumstances for the use of internal cardiac massage.     

心脏直视手术中心脏复苏困难的处理

目的：为提高心脏直视手术中心脏复苏率。方法：总结２０例心脏直视手术中心脏复苏困难的处理经验。结果：胸内心脏挤压和中等剂量心脏兴奋剂有利于心脏手术中的心脏复苏；心肌出现粗颤即应尽早除颤，不宜片面追求较高的心脏自动复跳率。对复苏困难病例，依其不同情况，在常规复苏方法的基础上，可采用一些特殊复苏措施，包括消除导致复苏困难的原因、长时间心脏挤压和长时间体外循环辅助、采用外科手段等。结论：有多种因素影响心脏直视手术中的心脏复苏，正确分析判断复苏困难的特殊原因，恰当地采用综合性措施（包括外科手段）进行复苏可收到良好效果。