Resuscitation
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Comparative Study
Defibrillation waveform and post-shock rhythm in out-of-hospital ventricular fibrillation cardiac arrest.
The importance of the defibrillation waveform on the evolving post-shock cardiac rhythm is uncertain. The primary objective of this study was to evaluate cardiac rhythms following the first defibrillation shock, comparing biphasic truncated exponential (BTE), monophasic damped sinusoidal (MDS), and monophasic truncated exponential (MTE) waveforms in patients experiencing out-of-hospital ventricular fibrillation cardiac arrest (OHCA). ⋯ In this retrospective cohort investigation, MDS and BTE waveforms had higher first shock defibrillation rates than the MTE waveform, while patients treated with the BTE waveform were more likely to develop an organized rhythm within 60 s of the initial shock. The results of this investigation, however, do not provide evidence that these surrogate advantages are important for improving survival. Additional investigation is needed to improve the understanding of the role of waveform and its potential interaction with other clinical factors in order to optimize survival in OHCA.
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Comparative Study
Antithrombin reduction after experimental cardiopulmonary resuscitation.
To determine whether activation of coagulation and inflammation during cardiac arrest results in a reduction of antithrombin (AT) and an increase in thrombin-antithrombin (TAT) complex during reperfusion. ⋯ AT is reduced and TAT and eicosanoids are increased after cardiac arrest, indicating activation of coagulation and inflammation.
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Automated external defibrillators (AEDs) have become increasingly available outside of the Emergency Medical Systems (EMS) community to treat sudden cardiac arrest (SCA). We sought to study the use of AEDs in the home, businesses and other public settings by minimally trained first responders. The frequency of AED use, type of training offered to first responders, and outcomes of AED use were investigated. In addition, minimally trained responders were asked if they had encountered any safety problems associated with the AED. ⋯ This survey demonstrates that AEDs purchased by businesses and homes were frequently taken to suspected cardiac arrests. Lay responders were able to successfully use the AEDs in emergency situations. Further, there were no reports of harm or injury to the operators, bystanders or patients from lay responder use of the AEDs.
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Comparative Study
Tracheal epinephrine or norepinephrine preceded by beta blockade in a dog model. Can beta blockade bestow any benefits?
Tracheal epinephrine (adrenaline) has been associated with two major deletorious side effects: increased heart rate (HR) and an initial decrease of blood pressure (BP). This prospective randomized animal study compared the haemodynamic responses to tracheally administered epinephrine or norepinephrine (nor adrenaline) alone versus each after pretreatment with propranolol for ameliorating those two untoward effects associated with epinephrine administration. Five anaesthetized mongrel dogs underwent 25 experiments of tracheal epinephrine or norepinephrine (0.02 mg/kg diluted with normal saline to 5 ml total volume) with or without an I/V non-selective beta-blocker (propranolol 0.1 mg/kg) pretreatment, and served as their own controls. ⋯ While both epinephrine or norepinephrine after pretreatment with propranolol produced a significant increase in both diastolic (from 106 to 166 mmHg and from 118 to 169 mmHg, respectively) (P<0.01) and mean BP (from 122 to 183 mmHg and from 133 to 188 mmHg, respectively) (P<0.01), only propranolol-pretreated tracheal epinephrine yielded a significant decrease in HR (from 52 to 33/m, P=0.002). Pretreatment with a beta-blocker protected against the deleterious tachycardia associated with epinephrine or norepinephrine and, by doing so, may improve the myocardial oxygen supply-and-demand balance. At the same time, the pretreatment augmented the relatively mild diastolic BP increase associated with the beta-adrenergic effect of epinephrine.