On account of the mechanical disturbance of external chest pressing to electrocardiogram (ECG) signal, the ECG rhythm cannot be identified reliably during the cardio-pulmonary resuscitation period. Whereas the possibility of successful resuscitation will be lowered due to interrupted external chest pressing, a new filtering algorithm, enhanced leastmean-square (eLMS) algorithm, was proposed and developed in our laboratory. The algorithm can filter the disturbance of external chest pressing without the support of hardware reference signal and correctly identify ventricular fibrillation (VF) rhythm and normal sinus rhythm in case of uninterrupted external chest pressing. Without other reference signals, this algorithm realizes filtering only through the interrupted electrocardiograma (cECG) signal. It was verified with ECG signal and disturbance signal under different signal to noise ratios and contrasted with other mature algorithms. The verification results showed that the identification effect of eLMS was superior to those of others under different signal to noise ratios. Furthermore, ECG rhythm can be correctly identified only through cECG signal. This algorithm not only reduces the research and development(R & D)costs of automated external defibrillator but also raises the identification accuracy of ECG rhythm and the possibility of successful resuscitation.
Objective To explore the effect of aortic root perfusion of amiodarone when intractable ventricular fibrillation occurs during valve replacement. Methods Totally 42 patients were selected as a drug group, who underwent intractable ventricular fibrillation following ascending aortic opening in valve replacement in Beijing Anzhen Hospital from October 2006 to October 2016. There were 26 males and 16 females with an average age of 56.31±12.56 years. The aorta was re-blocked when intractable ventricular fibrillation occured, amiodarone (150 mg diluted to 20 ml) through the aortic root perfusion tube was applicated, and suction was repeated 8-10 times with the cumulative amount of 150-200 ml, and then the ascending aorta was opened and fast compressed with a frequency of 200 times/min. While 53 patients with the same condition during the same period were selected as a control group. There were 35 males and 18 females with an average age of 58.79±19.81 years. The commonly used clinical treatment method of intractable ventricular fibrillation was adopted, such as continuous intravenous injection of 1 mg/kg lidocaine, while ascending aortic was re-blocked. The warm blood perfusion was given until the heart re-beated. The clinical outcomes were compared between the two groups. Results There was one perioperative death in the drug group and two deaths in the control group during perioperative period. Defibrillation frequency (3.11±0.59 times vs. 4.91±1.34 times, t=–2.917, P=0.000), heart rate 5 min after re-beating (91.65±9.81 beats/min vs. 98.32±10.21 beats/min, t=–2.019, P=0.032), cardiopulmonary bypass time (71.68±10.21 min vs. 81.59±12.93 min, t=–2.512, P=0.032), dopamine dosage (4.32±1.28 μg·kg–1·min–1 vs. 5.79±1.98 μg·kg–1·min–1, t=–2.781, P=0.015), epinephrine dosage (0.03±0.01 μg·kg–1·min–1 vs. 0.06±0.02 μg·kg–1·min–1, t=–3.996, P=0.000) and norepinephrine dosage (0.01±0.01 μg·kg–1·min–1 vs. 0.03±0.01 μg·kg–1·min–1, t=–4.163, P=0.000) of the drug group were significantly shorter or lower than those of the control group. The rate of cardiac rhythm 5 min after re-beating (42.8% vs. 9.4%, χ2=11.211, P=0.000) of the drug group was higher than that of the control group. Conclusion During intractable ventricular fibrillation following ascending aortic opening in valve replacemen, re-blocking the aorta and amiodarone reperfusion of the aortic root can significantly improve the heart re-beating rate and avoid ventricular re-fibrillation, shorten the cardiopulmonary bypass time and reduce the dosage of inotropic drugs.
American Heart Association (AHA) updated the advanced cardiovascular life support use of antiarrhythmic drugs during and immediately after cardiac arrest in the AHA guidelines for cardiopulmonary resuscitation and emergency cardiovascular care in November 2018. Based on the latest progress of relative evidence-based clinical evidence and 2015 AHA guidelines for cardiopulmonary resuscitation and cardiovascular emergency cardiovascular care. This update gave recommends on the use of antiarrhythmic drugs during resuscitation from adult shock-refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) cardiac arrest and immediately after restoration of spontaneous circulation following shock-refractory VF/pVT cardiac arrest, respectively. This review aims to interpret this update by reviewing the literature and comparing the recommends in this update with other guidelines.
As an important medical electronic equipment for the cardioversion of malignant arrhythmia such as ventricular fibrillation and ventricular tachycardia, cardiac external defibrillators have been widely used in the clinics. However, the resuscitation success rate for these patients is still unsatisfied. In this paper, the recent advances of cardiac external defibrillation technologies is reviewed. The potential mechanism of defibrillation, the development of novel defibrillation waveform, the factors that may affect defibrillation outcome, the interaction between defibrillation waveform and ventricular fibrillation waveform, and the individualized patient-specific external defibrillation protocol are analyzed and summarized. We hope that this review can provide helpful reference for the optimization of external defibrillator design and the individualization of clinical application.