Ventilation and cardiopulmonary resuscitation

Ventilation is essential for oxygenation of the alveoli and arterial blood. Comatose humans have upper airway soft tissue obstruction unless the head is tilted backwards and sometimes, in addition, the jaw thrust forward. In 1960, measurements on comatose humans with or without cardiac arrest, with or without a tracheal tube, showed essentially no ventilation by sternal compressions alone. This led to combining step A (airway control), step B (mouth-to-mouth ventilation), and step C (sternal (cardiac) compressions) into basic life support. In animal models, sternal compressions alone can produce some ventilation with or without a tracheal tube, because the straight upper airways of animals do not obstruct in coma. In witnessed sudden cardiac death, the C-A-B sequence makes physiological sense, but other causes of sudden coma need the A-B-C sequence. Lay persons should continue to be taught cardiopulmonary resuscitation steps A-B-C.     

Management of cardiopulmonary resuscitation

Since cardiopulmonary resuscitation was first described in 1960, it has become a standardized medical intervention. Separate guidelines have been developed for the neonatal and pediatric population, but none exist for the elderly population. This review will discuss recent available outcome data on resuscitation of the elderly and the known physiologic changes with aging that may affect decisions made during resuscitation.     

Pharmacology of cardiopulmonary resuscitation

Among the adrenergic receptor agonists, epinephrine, at alpha and beta stimulating doses, remains the drug of choice for cardiopulmonary resuscitation. However, alpha adrenergic agonists such as phenylephrine, methoxamine and dopamine (at alpha stimulating doses) result in similar success rates of resuscitation as epinephrine. In the opposite, beta adrenergic agonists, without or with only low alpha stimulating effect, such as isoproterenol or dobutamine are significantly less efficient. There are few data indicating that sodium bicarbonate improves outcome. Moreover it carries the risk of adverse effects. It may be of benefit in case of preexisting metabolic acidosis or during prolonged resuscitation with documented acidosis. Calcium remains indicated in case of hypocalcaemia, hyperkalaemia or calcium channel blocker intoxication. Severe ionized hypocalcaemia can occur after out-of-hospital cardiac arrest.     

Recent advances in cardiopulmonary resuscitation

Modern cardiopulmonary resuscitation (CPR) has been in existence for just over 40 years. Despite many advances, the overall survival following out-of-hospital cardiac arrest remains dismally poor. However, recent research has uncovered a number of areas of promise that may change this. Until now, all cardiac arrest victims whose initial rhythm is ventricular fibrillation have been managed the same with the emphasis on defibrillation as the initial treatment, irrespective of the time in arrest. Better understanding of the pathophysiology of prolonged arrest and studies in animal and man suggests that we should now question this concept and where there has been a delay, perform chest compressions and ventilation before attempting defibrillation. When defibrillation is required, most devices deliver a monophasic shock, despite the fact that for some time biphasic shocks have been known to be relatively more effective and less injurious. The adoption of biphasic waveforms for external defibrillation is increasing with the added advantage of smaller, lighter and more portable defibrillators. Finally, return of a spontaneous circulation does not always equate to a good outcome and many victims subsequently die from or suffer significant neurological injury. For the first time there now appears to be a method of improving outcome by instituting a period of mild hypothermia in those victims who have a return of their circulation but remain comatose. When put together, these changes offer the greatest chance for many years to improve the outcome of patients who suffer a cardiac arrest outside of the hospital environment.     

萨勃心肺复苏机在急诊心肺复苏中的应用研究

目的探讨萨勃心肺复苏机在心脏呼吸骤停患者进行心肺复苏中的应用价值。方法将2004年1月至2007年12月使用萨勃心肺复苏机抢救心脏呼吸骤停患者50例作为治疗组,2000年5月至2003年12月徒手心肺复苏抢救心脏呼吸骤停患者80例作为对照组。比较两组复苏中患者收缩压和血氧饱和度（以复苏开始5～10min时的数据作为统计资料）、自主循环恢复（ROSC）率、住院率、并发症发生情况。结果治疗组在改善心脏呼吸骤停患者的收缩压、血氧饱和度方面明显优于对照组,P〈0．05;治疗组ROSC率及住院率均高于对照组（分别为44％、40％与25％、21％）,P〈O．05。两组复苏期间主要并发症比较差异无统计学意义。结论萨勃心肺复苏机克服了徒手心肺复苏中因为医护人员或患者影响复苏效果的因素,使心肺复苏更趋标准有效。萨勃心肺复苏机能提高血液灌注压,增加每搏输出量,提高心脑的血氧供应,显著提高心肺复苏成功率,值得临床推广应用。     

电话心肺复苏研究进展

院外心脏骤停急救仍然是世界难题之一,此事件不仅发生率高并且由于大多突发、病情危机,以至预后不良。徒手心肺复苏术是应对该事件的有效手段,弥补了救护车到达前的空缺时间,改善预后。由于多种原因的影响,徒手心肺复苏术具有一定局限性。而电话心肺复苏的出现在一定程度上是对徒手心肺复苏术的改进。然而电话心肺复苏在实践过程中,所暴露出的弊端仍然会影响旁观者心肺复苏的质量。因此本研究对电话心肺复苏术的研究进展进行综述,以期推进电话心肺复苏术的发展与完善。     

New aspects of cardiopulmonary resuscitation

Objectives

To analyse the current knowledge based on the experimental and clinical research studies focused on cardiopulmonary resuscitation.

Data sources

International guidelines and recent review articles. Data collected from the Medline database with the keyword: cardiac arrest (CA).

Study selection

Research studies published during the last ten years were reviewed. Relevant clinical information was extracted and discussed.

Data synthesis

Last guidelines include significant modification in the management of cardiac arrest patient. Recognition of CA by lay rescuers is done on the absence of vital sign (no reactivity, no breathing) and it is now only recommended for healthcare providers to check the pulse. It is confirmed that chest compression has to prevail over ventilation and has to be done at a rate of 100 compressions per minutes with a compression-ventilation ratio of 30: 2. A short period of CPR before attempting defibrillation may be considered in adults with out-of-hospital ventricular fibrillation (VF) or pulseless ventricular tachycardia and a delay to EMS response. Defibrillation is provided with biphasic waveform at 150–200 J and is immediately followed by a 2 min period of CPR. Adrenaline remains the drug of choice in cardiac arrest whatever the first rhythm because no benefit has been demonstrated with vasopressin in term of survival. Amiodarone is the first line antiarrhythmic, improves short-term survival and is currently recommended after the second shock for resistant VF. Postresuscitation treatment is now receiving greater emphasis in emergency cardiovascular care, but there is little evidence to support specific therapies with the exception of hypothermia (12–24 h at 32–34 °C) that is currently recommended if patient remains unconscious after VF. Revascularization should also be discussed if CA is presumed to be from ischemic origin.

Conclusion

The last international 2005 guidelines include significant modifications of CPR. However, many questions remain unresolved and controlled studies are still needed before other changes could be recommended for routine practice. Our greatest challenge and highest priority is the training of lay rescuers and healthcare providers in simple, high-quality CPR skills that can be easily taught, remembered, and implemented to save lives.     

News in cardiopulmonary resuscitation in adults

In the paper it is presented novelties in cardiopulmonary resuscitation of adults. It was indicated to importance of maintenance of cardiac output as main factor of successful resuscitation. In was pointed out defibrilation by automatic external defibrilators (AED), especially of biphasic type. Recapitulation of the nevelties was also stated.     

Variation in serum ionized calcium on cardiopulmonary resuscitation

Changes in serum ionized calcium (Ca⁺⁺) levels during cardiopulmonary resuscitation (CPR) and before and after CaCl₂ administration have been examined and investigated in 30 patients with cardiopulmonary arrest on arrival (dead on arrival patients) when a significant negative correlation was found to exist between the transportation time and aCa⁺⁺, as the aCa⁺⁺ level decreased with an increase in the transportation time. Upon arrival, the pH had fallen due to acidosis so that aCa⁺⁺ and cCa⁺⁺ levels were virtually normal. After admission, the pH rose as a result of CPR, resulting in a significant drop in both Ca⁺⁺ levels, so that in most cases resuscitation was not possible. Those successfully resuscitated took over 60min to return to normal Ca⁺⁺ levels. Administration of approximately 6.6mg/kg of CaCl₂ led to significant increases in aCa⁺⁺ and cCa⁺⁺ to essentially normal levels, even with some patients recording extremely elevated Ca levels, even with some patients recording extremely elevated Ca levels. However, the success rate of resuscitation was not found to show any significant difference according to whether CaCl₂ had or had not been administrated.Thus, it is felt necessary to re-examine the use of calcium chloride on CPR.(Gando S, Tedo I, Tujinaga H et al.: Variation in serum ionized calcium on cardiopulmonary resuscitation. J Anesth 2: 154–160, 1988)     

阻力单向活瓣在心肺复苏中的应用——一种新的心肺复苏技术

心肺复苏(cardiopulmonary resuscitation,CPR)成功率和存活率仍然很低,主要原因是CPR期间回心血量少,心脏和脑灌注不足。增加胸内负压的措施和器材明显提高心肺复苏的效果[1~4]。近来,Lu-rie等[5~10]又研制出在胸壁放松时增加胸内负压的阻力单向活瓣(inspiratory impedance threshold valve(device),ITV or ITD),使心肺复苏的效果进一步提高。1阻力单向活瓣应用的理论基础胸外按压是CPR的主要措施,临床应用已逾半个世纪。曾经认为,胸外按压作用于前胸壁,把心脏压向脊柱,随着连续性压-放动作的交替和循环,血液流入和流出心脏而产生人…     

Single operator cardiopulmonary resuscitation in ambulances

Cardiopulmonary resuscitation en route to hospital is performed by a single-handed operator in many British ambulances. In this study, three emergency ventilation devices, and mouth-to-mouth breathing, were compared for effectiveness in unintubated patients. Seventeen paramedics used each method on a Laerdal manikin in a randomised order, under identical conditions. Three experienced cardiopulmonary resuscitation instructors repeated the tests in a moving ambulance. There were significant differences in minute volume (p less than 0.01) and number of effective chest compressions (p less than 0.05); mouth-to-mouth breathing produced the best overall results and the simplest device was a close second. The value of automatic ventilators for single-operator cardiopulmonary resuscitation in unintubated patients is questioned.     

Prehospital cardiopulmonary resuscitation in the pediatric trauma patient

Purpose

Children requiring prehospital cardiopulmonary resuscitation (CPR) after traumatic injury have been shown to have poor survival. However, outcome of children still receiving CPR on-arrival by emergency medical service to the emergency department (ED) has not been demonstrated in a published clinical series.

Methods

An 11-year retrospective analysis from a level I pediatric trauma center of the outcomes of children requiring prehospital CPR after traumatic injury was undertaken. Outcome variables were stratified by survival, death, and CPR on-arrival.

Results

Of 169 children requiring prehospital CPR, there were 28 survivors and 141 deaths. Of 69 children requiring CPR on-arrival to the ED, there were no survivors. There were 70 females and 99 males. Mean age of survivors was 3.4 years; nonsurvivors, 8.8 years; and 4.6 years for CPR on-arrival. Thirty-nine percent of all injuries were sustained in motor vehicle collisions; 20%, motor pedestrian collisions; 19%, assaults; 7%, falls; 4%, all terrain vehicle/motorcycle/bicycle; and 4%, gunshot wounds. Forty-two percent of all patients expired in the ED, whereas 34% expired in the intensive care unit. Eighty-seven percent of CPR on-arrival patients expired in the ED. Fifty-five percent of survivors had full neurologic recovery.

Conclusion

Although mortality was extremely high for children requiring CPR in the field After traumatic injury, it was absolute for those arriving at the ED still undergoing CPR.