The natural biochemical changes during ventricular fibrillation with cardiopulmonary resuscitation and the onset of postdefibrillation pulseless electrical activity
ABSTRACT The objective of this study was to document the biochemical changes during ventricular fibrillation (VF) with cardiopulmonary resuscitation (CPR), and to identify factors associated with postdefibrillation pulseless electrical activity (PD-PEA).
It has been reliably estimated that as much as 60% of out-of-hospital sudden cardiac death can be attributed to the onset of PD-PEA (Niemann JT, Cruz B, Garner D et al. Immediate countershock versus CPR before countershock in a 5-minute swine model of ventricular fibrillation arrest. Ann Emerg Med 2000;36:543-6). Previous attempts to treat reversible causes of pulseless electrical activity have not been successful clinically (Niemann JT, Stratton SJ, Cruz B, Lewis RJ. Outcome of out-of-hospital postcountershock asystole and pulseless electrical activity versus primary asystole and pulseless electrical activity. Crit Care Med 2001;29:2366-70).
This investigation used 22 studies on 14 anesthetized pigs breathing 100% oxygen. Ventricular fibrillation was induced with a right ventricular catheter electrode, and the chest was compressed with a pneumatically driven Chest Thumper (Michigan Instruments) (80-100 lb at 60/min). The electrocardiogram and aortic pressure were recorded continuously. Arterial pH, P(O2), P(CO2), Na+, K+, Ca2+, Cl-, SaO2, glucose, hematocrit, and hemoglobin level were measured at selected times. Ventricular defibrillation was achieved with transchest electrodes.
Typically, during VF with CPR, mean aortic pressure was 20 to 25 mm Hg. In all cases aortic P(O2) decreased to about 20% of the initial value in 10 minutes, and aortic blood K+ increased by 50% in 6 minutes. By 5 to 8 minutes, the incidence of PD-PEA was 50%.
Ventricular fibrillation duration, arterial K+, and arterial P(CO2) were statistically correlated with the onset of PD-PEA in this study. In addition, trends suggest an association of mean arterial blood pressure and arterial P(O2) with the onset of PD-PEA.
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ABSTRACT: To systematically evaluate the evidence of the effect of advanced life support techniques on outcome in veterinary cardiopulmonary resuscitation (CPR) and to outline knowledge gaps. Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. Academia, referral practice, and general practice Sixteen population, intervention, control group, outcome questions were evaluated to determine if recommendations could be made concerning drug therapy, including vasopressors, vagolytics, corticosteroids, reversal agents, buffer therapy, and correction of electrolyte disturbances. Electrical defibrillation strategies as well as other advanced interventions such as open-chest CPR, impedance threshold devices, and special considerations regarding anesthesia-related cardiopulmonary arrest (CPA) were also investigated. There is strong evidence supporting the use of standard-dose (0.01 mg/kg) epinephrine in CPR, as well as early electrical defibrillation for animals experiencing CPA due to ventricular fibrillation or pulseless ventricular tachycardia, preferentially using a biphasic defibrillator. For CPA due to certain causes and with the availability of advanced postcardiac arrest support, open chest CPR is preferred. Many knowledge gaps regarding other pharmacologic and advanced therapies were identified, and further studies are recommended to better systematically address these questions.06/2012; 22 Suppl 1:S44-64. DOI:10.1111/j.1476-4431.2012.00755.x
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ABSTRACT: Objective: We investigated the influence of β-receptor blocker metoprolol on return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) in rats with induced myocardial infarction (MI). Methods: Male Sprague-Dawley rats were randomly divided into three groups: the sham-operated group, the MI group without metoprolol, which was fed the vehicle, and the MI+metoprolol group receiving intragastric metoprolol. Each group was further divided randomly into three subgroups, depending on the dosage of epinephrine administered during subsequent CPR applied after the induction of asphyxial cardiac arrest. Results: The ROSC rate was significantly decreased in the low dose subgroup of MI group, unchanged in the medium dose subgroup of MI group, and significantly decreased in the high dose subgroup of MI group, compared with the same dose subgroup of sham-operated group. MI+metoprolol group had a lower ROSC rate than MI group in the medium dose subgroup, and a higher ROSC rate than MI group in the high dose subgroup. There was no difference in blood K(+) values of successful rats between MI group and MI+metoprolol group. The rats with successful CPR had lower blood K(+) values than rats with unsuccessful CPR in each of the three treatment groups. Conclusions: Metoprolol administered to MI rats over a long period significantly improved ROSC rates under an appropriate dose of epinephrine during CPR. An increasing high blood K(+) value would attenuate the rate of a successful CPR.Journal of Zhejiang University SCIENCE B 06/2013; 14(6):505-10. DOI:10.1631/jzus.B1200293 · 1.29 Impact Factor
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ABSTRACT: Objective To report acid base, electrolyte, glucose, and lactate values collected during or immediately after cardiopulmonary resuscitation (CPR) in dogs and cats.DesignRetrospective study.SettingUniversity Teaching Hospital.AnimalsThirty-two dogs and 10 cats.InterventionsNone.Measurements and Main ResultsBlood gas, electrolyte, glucose, and lactate values measured during CPR or within 5 minutes of return of spontaneous circulation (ROSC) were retrospectively evaluated. The time of blood collection with respect to the occurrence of cardiopulmonary arrest (CPA), the initiation of CPR or ROSC was noted. Forty-two venous blood samples were analyzed, 24 collected during CPR and 18 samples were collected within 5 minutes of ROSC. Metabolic acidosis and hyperlactatemia were evident in all samples in the study while an increased PvCO2 occurred in 88% of samples collected during CPR and in 61% of samples collected following ROSC. Hyperkalemia occurred in 65% of all cases, decreased ionized calcium was evident in 18%, hypoglycemia was evident in 21% while hyperglycemia was evident in 62%. There was no significant difference in any parameter evaluated between dogs and cats during CPR.There was no significant difference of any variable measured during the first 15 minutes of CPA versus those measured more than 15 minutes following CPA. When the values measured during the first 5 minutes of ROSC were compared to those measured during CPR, the pH and PvO2 were significantly lower in the CPR group.Conclusions Biochemical abnormalities including metabolic acidosis, hyperkalemia, ionized hypocalcemia, hypoglycemia, and hyperglycemia can be identified during CPR and immediately following ROSC. The therapeutic and prognostic relevance of these changes are yet to be defined and may prove to be useful to guide patient management in the future.03/2014; 24(2). DOI:10.1111/vec.12151