摘要:

Immediate defibrillation is the single most effective therapy to reverse ventricular fibrillation cardiac arrest today. The once physician-only skill of defibrillation has entered mainstream society and is saving the lives of many sudden cardiac arrest (SCA) victims in a variety of settings. The automated external defibrillator (AED) and the concept of public access defibrillation (PAD) are a result of collaborative efforts between the American Heart Association (AHA) and medical manufacturers. Today, airports, airlines, casinos, cruise ships, and other public venues have modernized their first aid kits to include an AED. The success of these programs has ignited a trend in public safety and subsequently marketed the worth of AEDs in the home. Although optimal placement of AEDs remains uncertain, PAD is showing great promise in reducing the death rate from SCA. The lay public, both trained and untrained, is emerging as the next level of emergency care responders able to use a defibrillator.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The introduction of the 2000 Guidelines for Cardiopulmonary Resuscitation emphasizes a new, evidence-based approach to the science of ventilation during cardiopulmonary resuscitation (CPR). New laboratory and clinical science underemphasizes the role of ventilation immediately after a dysrhythmic cardiac arrest (arrest primarily resulting from a cardiovascular event, such as ventricular defibrillation or asystole). However, the classic airway patency, breathing, and circulation (ABC) CPR sequence remains a fundamental factor for the immediate survival and neurologic outcome of patients after asphyxial cardiac arrest (cardiac arrest primarily resulting from respiratory arrest). The hidden danger of ventilation of the unprotected airway during cardiac arrest either by mouth-to-mouth or by mask can be minimized by applying ventilation techniques that decrease stomach gas insufflation. This goal can be achieved by decreasing peak inspiratory flow rate, increasing inspiratory time, and decreasing tidal volume to approximately 5 to 7 mL/kg, if oxygen is available. Laboratory and clinical evidence recently supported the important role of alternative airway devices to mask ventilation and endotracheal intubation in the chain of survival. In particular, the laryngeal mask airway and esophageal Combitube proved to be effective alternatives in providing oxygenation and ventilation to the patient in cardiac arrest in the prehospital arena in North America. Prompt recognition of supraglottic obstruction of the airway is fundamental for the management of patients in cardiac arrest when ventilation and oxygenation cannot be provided by conventional methods. “Minimally invasive” cricothyroidotomy devices are now available for the professional health care provider who is not proficient or comfortable with performing an emergency surgical tracheotomy or cricothyroidotomy. Finally, a recent device that affects the relative influence of positive pressure ventilation on the hemodynamics during cardiac arrest has been introduced, the inspiratory impedance threshold valve, with the goal of maximizing coronary and cerebral perfusion while performing CPR. Although the role of this alternative ventilatory methodology in CPR is rapidly being established, we cannot overemphasize the need for proper training to minimize complications and maximize the efficacy of these new devices.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Basic life support and rapid defibrillation for ventricular fibrillation or pulseless ventricular tachycardia are the only two interventions that have been shown unequivocally to improve survival after cardiac arrest. Several drugs are advocated to treat cardiac arrest, but despite very encouraging animal data, no drug has been reliably proven to increase survival to hospital discharge after cardiac arrest. This review focuses on recent experimental and clinical data concerning the use of vasopressin, amiodarone, magnesium, and fibrinolytics during advanced life support (ALS). Animal data indicate that, in comparison with epinephrine (adrenaline), vasopressin produces better vital organ blood flow during cardiopulmonary resuscitation (CPR). These apparent advantages have yet to be converted into improved survival in large-scale trials of cardiac arrest in humans. Data from two prospective, randomized trials suggest that amiodarone may improve short-term survival after out-of-hospital ventricular fibrillation cardiac arrest. On the basis of anecdotal data, magnesium is recommended therapy fortorsades de pointesand for shock-resistant ventricular fibrillation associated with hypomagnesemia. In the past, CPR has been a contraindication to giving fibrinolytics, but several studies have demonstrated the relative safety of fibrinolysis during and after CPR. Fibrinolytics are likely to be beneficial when cardiac arrest is associated with plaque rupture and fresh coronary thrombus or massive pulmonary embolism. Fibrinolysis may also improve cerebral microcirculatory perfusion once a spontaneous circulation has been restored. A planned, prospective, randomized trial may help to define the role of fibrinolysis during out-of-hospital CPR.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Cardiac arrest survival rates remain low despite increased access to advanced cardiac life support. Survival from cardiac arrest is, at least in part, related to the perfusion pressures and blood flow achieved during cardiopulmonary resuscitation (CPR). A number of alternative CPR devices have been developed that aim to improve the perfusion pressures and/or blood flow achieved during CPR. Active compression-decompression CPR devices are by far the most studied alternative CPR devices, but the results have been inconsistent and conflicting. A number of other devices, including the inspiratory impedance threshold valve, minimally invasive direct cardiac massage, phased chest and abdominal compression-decompression CPR, and vest CPR, are all capable of improving perfusion pressures and/or blood flow compared with standard external chest compressions. However, no convincing human outcome data has been produced yet for any of these devices. Although an interesting area of research, none of the alternative CPR devices convincingly improve long-term patient outcomes.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Despite all of the progress in reanimating patients in cardiac arrest over the last half century, resuscitation attempts usually fail to restore spontaneous circulation. Thus, the most common of all resuscitation decisions after initiation remains the decision to stop. An entire library of research and guidelines for terminating resuscitative efforts has been developed in the past decade. However, this most central decision is often left open to chance, provider preference, family wishes, futility judgments, and resource concerns—a host of subjective considerations at the bedside and beyond. This article sheds light on these considerations, acknowledging the pivotal role that resuscitation science and guidelines can play in the multifactorial decision to discontinue resuscitative efforts.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Acute coronary syndromes represent the acute, life-threatening phases of coronary heart disease. Patients with acute coronary syndromes are at high risk of major adverse cardiac events. Treatment of these patients remains controversial because of the heterogeneous nature of these conditions and recent advances in their management options. The older standbys of aspirin, heparins, nitrates, &bgr;-blockers, and thrombolytic therapy have given way to vastly improved interventional capabilities (with improved adjunctive pharmacotherapy), low molecular weight heparins, glycoprotein IIb/IIIa antagonists, safer theinopyridines, thrombin inhibitors, and newer generation fibrinolytics. Despite these substantial advances, a great deal of confusion remains. Clinicians know that there are better forms of therapy but are not sure how to use them, when to use them, or even what to use. They do not have all the answers at present and probably have more questions than answers.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Distributive shock is a common problem in intensive care. Systemic hypotension is a medical emergency and will cause end-organ injury if not reversed. There are relatively few medications available to treat distributive shock. Catecholamines are most widely used for this indication and work by stimulating &agr;- andagr;-and/or &bgr;-adrenergic receptors. Vasopressin and corticosteroids may have a role in reversing refractory shock and work primary through nonadrenergic mechanisms. Shock is difficult to define using hemodynamic criteria, because the same hemodynamic values can be normal in one patient, yet represent shock in another. Thus, the appropriate therapeutic endpoints for vasopressor therapy are not uniform for all patients. Similarly, the available evidence comparing vasopressor agents in terms of safety and efficacy is limited. When used at doses necessary to reverse distributive shock, less potent vasoconstrictors (eg, dopamine) do not appear to be safer than more potent ones (eg, norepinephrine) and do not appear to be as effective.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

When subjected to a period of oxygen deprivation, endothelial cells exhibit a characteristic pattern of responses that can be considered either adaptive or pathologic, depending on the circumstances. In this review, the molecular basis for these responses is detailed. Hypoxia shifts the endothelial phenotype towards one in which anticoagulant properties are diminished, permeability and leukoadhesivity are increased, and proinflammatory features dominate the endovascular milieu. Of all the different points of intersection between the coagulation and inflammatory axes in the vasculature, perhaps most fundamentally, hypoxia alters several key transcriptional factors, including early growth response gene 1 (Egr1) and hypoxia-inducible factor (HIF) 1, which coordinate separate programs of gene activation. The preponderance of forces in the hypoxic endovascular environment, perhaps designed as an evolutionary adaptation to oxygen deprivation, can trigger severe, pathologic, clinical consequences in the setting of tissue ischemia.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Controversy concerning the pulmonary artery catheter (PAC) and its use as a bedside clinical tool continues to be a significant bone of contention. In the pursuit of evidence-based medicine, a substantial effort has been made over the last 25 years to demonstrate the benefit or lack thereof of PAC-led therapy, and this endeavor still persists with large, randomized, clinical trials currently in progress both in the United States and in the United Kingdom. This article reviews the core evidence for and against PAC efficacy and safety and considers the most appropriate method for validation of such a device.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Lithium dilution cardiac output (LiDCO™; LiDCO, London, UK) is a minimally invasive indicator dilution technique for the measurement of cardiac output. It was primarily developed as a simple calibration for the PulseCO™ (LiDCO, London, UK) continuous arterial waveform analysis monitor. The technique is quick and simple, requiring only an arterial line and central or peripheral venous access. These lines would probably already have been inserted in critical care patients. A small dose of lithium chloride is injected as an intravenous bolus, and cardiac output is derived from the dilution curve generated by a lithium-sensitive electrode attached to the arterial line. Studies in humans and animals have shown good agreement compared with results obtained with other techniques, and the efficacy of LiDCO™ in pediatric patients has also been proven. Compared with thermodilution, lithium dilution showed closer agreement in clinical studies with electromagnetic flow measurement.PulseCO™ is a beat-to-beat cardiac output monitor that calculates stroke volume from the arterial pressure waveform using an autocorrelation algorithm. The algorithm is not dependent on waveform morphology, but, rather, it calculates nominal stroke volume from a pressure–volume transform of the entire waveform. The nominal stroke volume is converted to actual stroke volume by calibration of the algorithm with LiDCO™. Initial studies indicate good fidelity, and the results from centers in the United States and the United Kingdom are extremely encouraging. The PulseCO™ monitor incorporates software for interpretation of the hemodynamic data generated and provides a real-time analysis of arterial pressure variations (ie, stroke volume variation, pulse pressure variation, and systolic pressure variation) as theoretical guides to intravascular and cardiac filling.

ISSN:1070-5295    

出版商:OVID    

年代:2002

数据来源: OVID