Current opinion in critical care
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Curr Opin Crit Care · Jun 2002
ReviewAlternative ventilation strategies in cardiopulmonary resuscitation.
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). ⋯ 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.
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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. ⋯ 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.
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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). ⋯ 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.
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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.
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Curr Opin Crit Care · Apr 2002
ReviewAdvanced monitoring in the intensive care unit: brain tissue oxygen tension.
Cerebral monitoring of patients with acute intracranial disorders generally focuses on intracranial pressure and cerebral perfusion pressure monitoring. Over the past few years, several new techniques have become available for more detailed routine monitoring of cerebral oxygenation and metabolism. Brain tissue oxygen pressure measurement is increasingly being used for evaluation of cerebral oxygenation. ⋯ Published experimental and clinical data are considered, and the current status of the clinical use and indications of the technique are summarized. Monitoring may be performed in relatively undamaged parts of the brain or, preferably, in the penumbra region of an intracerebral lesion. Pathophysiologic evidence warrants targeting therapy for patients with traumatic brain injury and subarachnoid hemorrhage toward improvement of cerebral oxygenation guided by continuous monitoring of brain tissue oxygen tension.