A dose-response curve for the negative bias pressure of an intrathoracic pressure regulator during CPR

An intrathoracic pressure regulator (ITPR) is a device that can be added to the external end of an endotracheal tube to create controlled negative airway pressure between positive pressure ventilations. The resulting downward bias of the airway pressure baseline promotes increased venous return and enhanced circulation during CPR and also during hypovolemic shock. In the present study we exercised a mathematical model of the human cardiopulmonary system, including airways, lungs, a 4 chambered heart, great vessels, peripheral vascular beds, and the biomechanics of chest compression and recoil, to determine the relationship between systemic perfusion pressure during CPR and the value of baseline negative airway pressure in an ITPR. Perfusion pressure increases approximately 50 percent as baseline airway pressure falls from zero to –10 cm H2O. Thereafter perfusion pressure plateaus. Negative bias pressures exceeding –10 cm H2O are not needed in ITPR-CPR

Reduced Atrial Tachyarrhythmia Susceptibility After Upgrade of Conventional Implanted Pulse Generator to Cardiac Resynchronization Therapy in Patients with Heart Failure

OBJECTIVES: We sought to identify the impact of cardiac resynchronization therapy (CRT) on atrial tachyarrhythmia (AT) susceptibility in patients with left ventricular (LV) systolic dysfunction in whom worsening heart failure (HF) resulted in upgrade from conventional dual-chamber pulse generator to cardiac resynchronization therapy-defibrillator (CRT-D). BACKGROUND: Cardiac resynchronization therapy with a defibrillator improves survival rates and symptoms in patients with LV systolic dysfunction but little is known about its effects on AT incidence in the same patient population. METHODS: Twenty-eight consecutive HF patients who underwent device upgrade to CRT-D were included. Patients had \u3e or =2 device interrogations in the 1 year before upgrade and \u3e or =3 interrogations in the 18- to 24-month follow-up after upgrade. Echocardiographic parameters were assessed before and at 3 to 6 months after CRT-D. Additional observations included number of hospital stays, HF clinical status, and concomitant pharmacological therapy. By virtue of this study design, each patient served as his/her own control. Statistical analysis was performed by 2-tailed paired t test and with nonparametric tests where appropriate. RESULTS: Within 3 months after CRT, the number of HF patients with documented AT decreased significantly from the immediate pre-CRT value and tended to decline with time. At 1-year follow-up, 90% of patients were AT-free compared with 14% of patients 3 months before CRT (p \u3c 0.001). Furthermore, the number of AT episodes/year and their maximum duration decreased after CRT (mean +/- SD; 181 +/- 50 vs. 50 +/- 20.2, p \u3c 0.05, and 220.8 +/- 87 s vs. 28 +/- 21 s, p \u3c 0.05, respectively). Finally, CRT was associated with improved LV ejection fraction (mean +/- SD; from 26 +/- 5.3% to 31 +/- 7%, p \u3c 0.001) and reduced number of HF or arrhythmia hospital stays (p \u3c 0.05). CONCLUSIONS: Our findings support the view that CRT might decrease AT susceptibility in HF patients with LV systolic dysfunctio

Post-conditioning to improve cardiopulmonary resuscitation

International audienc

Venoarteriovenous ECMO in Concomitant Acute Respiratory Distress Syndrome and Cardiomyopathy Associated with COVID-19 Infection

In the most severe cases, novel coronavirus (SARS-CoV-2) infection leads to Acute Respiratory Distress Syndrome which may be refractory to standard medical interventions including mechanical ventilation. There are growing reports of the use of venovenous (VV) extracorporeal membrane oxygenation (ECMO) in these cases. A subset of critically ill COVID-19 patients develops cardiomyopathy as well, manifested by cardiogenic shock with reduced ejection fraction, dysrhythmias, and subsequent increase in mortality. One strategy for managing ARDS with an element of cardiogenic shock is venoarteriovenous (VAV) ECMO. Less than 1% of the cases in the worldwide ELSO COVID-19 database employed any form of hybrid cannulation. To date, there has only been one reported case of patient salvage with arterial or partial arterial support. We present a case that demonstrates the potential role of VAV ECMO in the case of concomitant severe ARDS with cardiomyopathy in the setting of COVID-19 infection