Weaning from Impella and mobilization of Impella patients

Weaning of patients from Impella is complex and includes evaluation of the underlying disease, which is essential for estimating the potential for heart recovery. Monitoring during the weaning phase with echocardiography and pulmonary artery catheters will be discussed, as well as the use of intravenous and oral heart failure drugs. Patients who are candidates for weaning must be stable, without inotropes, and must have recovered from acute end-organ damage. Coronary artery disease and valvular heart diseases should be appropriately addressed before weaning to take the maximum advantage of haemodynamic stability provided by the support and to maximize the possibility of weaning. Tips and tricks for the mobilization of Impella patients will also be discussed.

Pump flow setting and assessment of unloading in clinical practice

The rationale for mechanical circulatory support (MCS) in cardiogenic shock is to restore cardiac output in selected patients when critically low or in case of refractory cardiac arrest. Furthermore, an MCS device that moves blood from either the left atrium or the left ventricle to the systemic circulation will potentially unload the ventricle. These devices are used alone or in combination with venoarterial extracorporeal membrane oxygenation (VA-ECMO). If a left-sided Impella device is used, it should be run at the highest possible performance level during treatment while avoiding suction events. When combined with VA-ECMO, the Impella device should be run at a lower performance level, ensuring sufficient left ventricular emptying but avoiding suction. Continuous monitoring is pivotal and patients managed outside the catheterization laboratory should be monitored with an arterial line, a central venous catheter, frequent use of pulmonary artery catheters and regular imaging by transthoracic echocardiogram.

Safety First: An Ambulation Protocol for Patients With Pulmonary Artery Catheters

Background Patients with indwelling pulmonary artery catheters have historically been excluded from participating in early mobility programs because of the concern for catheter-related complications. However, this practice conflicts with the benefits accrued from early mobilization. Objective The purposes of this quality improvement project were to develop and implement a standardized ambulation protocol for patients with a pulmonary artery catheter in a cardiac surgery intensive care unit and to assess and support safe ambulation practices while preventing adverse events in patients with pulmonary artery catheters. Methods From October 2016 through October 2017, this single-center quality improvement project developed and analyzed the implementation of a safe patient ambulation protocol in the cardiac surgery intensive care unit. Frontline nursing staff and the interdisciplinary team were educated on a standardized protocol that facilitated patient ambulation. Data analyzed included distance of ambulation, catheter migration, presence of cardiac dysrhythmias, and adverse events during ambulation. Results During this 1-year project, 41 patients participated in 94 walks for a total distance of 13 676.38 m. There were no reported episodes of cardiac dysrhythmia, accidental occlusion of the pulmonary artery, catheter migration, or pulmonary artery rupture related to ambulation with a pulmonary artery catheter. Conclusions The use of a standardized ambulation protocol can successfully result in safe mobilization of patients with indwelling pulmonary artery catheters.

A dynamic model of the body gas stores for carbon dioxide, oxygen and inert gases that incorporates circulatory transport delays to and from the lung.

Many models of the body's gas stores have been generated for specific purposes. Here, we seek to produce a more general purpose model that: i) is relevant for both respiratory (CO2 and O2) and inert gases; ii) is based firmly on anatomy and not arbitrary compartments; iii) can be scaled to individuals; and iv) incorporates arterial and venous circulatory delays as well as tissue volumes so that it can reflect rapid transients with greater precision. First, a 'standard man' of 11 compartments was produced, based on data compiled by the International Radiation Protection Commission. Each compartment was supplied via its own parallel circulation, the arterial and venous volumes of which were based on reported tissue blood volumes together with data from a detailed anatomical model for the large arteries and veins. A previously published model was used for the blood gas chemistry of CO2 and O2. It was not permissible ethically to insert pulmonary artery catheters into healthy volunteers for model validation. Therefore, validation was undertaken by comparing model predictions with previously published data and by comparing model predictions with experimental data for transients in gas exchange at the mouth following changes in alveolar gas composition. Overall, model transients were fastest for O2, intermediate for CO2 and slowest for N2. There was good agreement between model estimates and experimentally measured data. Potential applications of the model include estimation of closed-loop gain for the ventilatory chemoreflexes, and improving the precision associated with multibreath washout testing and respiratory measurement of cardiac output.

Transthoracic intracardiac catheters in perioperative management of pediatric cardiac surgery patients: a single-center experience

Background Transthoracic intracardiac catheters inserted under direct vision in the pulmonary artery and left atrium during cardiac surgery play major roles in the management of patients with complex congenital heart disease. We aimed to analyze the utility of transthoracic intracardiac catheters in the perioperative management of pediatric cardiac surgery patients and review catheter-related morbidity. Methods The computerized register of all pediatric cardiac surgery patients in whom transthoracic intracardiac catheters were inserted from 2012 to 2019 in a tertiary referral center were reviewed. Results Transthoracic pulmonary artery and left atrial catheters were inserted in 89 and 71 patients, respectively. The most common indications for pulmonary artery and left atrial catheters were total anomalous pulmonary venous connection (52%) and total cavopulmonary connection (58%) respectively. The most common reason for elevated pulmonary artery and left atrial pressure after cardiopulmonary bypass was left ventricular dysfunction. Transthoracic pulmonary artery catheters helped in diagnosing pulmonary hypertensive crisis (29%), surgical decision-making (14%), and ventilator therapy (16%). Left atrial catheters helped in the diagnosis of left ventricular dysfunction (54%). The incidence of morbidity was 8.9% for transthoracic pulmonary artery catheters and 9.8% for left atrial catheters. Conclusion Transthoracic pulmonary artery catheters help in the diagnosis and management of pulmonary hypertensive crisis, for making perioperative surgical decisions, and during ventilator therapy. Transthoracic left atrial catheters help in the diagnosis of left ventricular dysfunction in the perioperative period. The diagnostic and treatment benefits provided by transthoracic intracardiac catheters outweigh the minor adverse events, supporting their continued use in the perioperative period.

Abstract 14420: Outcomes in Women With Cardiogenic Shock: Data From the Critical Care Cardiology Trial Network (CCCTN)

Introduction: Although sex-specific differences in treatment and outcomes of patients with acute myocardial infarction complicated by cardiogenic shock (AMICS) have been described, little is known about sex-specific differences in acute decompensated heart failure-related CS (ADHF-CS). Methods: The CCCTN is an investigator-initiated multicenter network of cardiac intensive care units (CICUs) in North America. Consecutive admissions (n=8240) to the CICU during annual snapshots (mostly 2 months) were submitted to the coordinating center (TIMI Study Group, Boston, MA). Patients were stratified by sex and type of CS. Adjustments were made for age and SOFA score. Results: Between 2017 and 2019, 1487 admissions were for CS of which 879 (33% women) were for ADHF-CS. In this cohort, age (median 62 y), race, and BMI (median 28 kg/m 2 ) did not differ by sex. Women and men also had similar SOFA and IABP-SHOCK II scores. Women were less likely to have CKD (28% vs 42%, p=<0.001) and CAD (28% vs 45%, p<0.001) but were significantly more likely to have underlying pulmonary disease (23% vs 15%, p<0.01). Although women and men had a similar burden of pre-existing HF (72% vs 75%, p=0.35), women were more likely to have HF with preserved ejection fraction (19% vs. 5%, p<0.001). Women had shorter CICU stays (4.0 vs 5.5 days, p<0.001), and numerically, though not significantly, lower use of pulmonary artery catheters (48% vs 53%, p=0.13) and mechanical circulatory support (28% vs 34%, p=0.11). In-hospital mortality in women with ADHF-CS was significantly higher than in men (39% vs 26%, p<0.001, adj-OR 2.05 (95% CI 1.47-2.86; p<0.001)). In contrast, in-hospital mortality for AMICS did not differ by sex (38% vs 40%, p=0.69). Conclusions: Compared to men, women admitted to the CICU with ADHF-CS had higher mortality despite similar indices of illness severity. The reason(s) behind this difference merit further study.

Postoperative Ventricular Fibrillation

This chapter assesses ventricular arrhythmias. The most common ventricular arrhythmias are premature ventricular complexes (PVCs). Occasional PVCs are rarely harmful and may be related to tissue reperfusion or electrolyte abnormalities. Other types of ventricular arrhythmias are non-sustained ventricular tachycardia and ventricular tachyarrhythmias, which include ventricular tachycardia and ventricular fibrillation. Ventricular tachycardia is defined as a rate >100 bpm with 3 or more ventricular complexes in a row, which is sustained. Meanwhile, ventricular fibrillation is a form of complex ventricular arrhythmias and usually indicates a left ventricular problem. The possible causes of ventricular arrhythmias in the perioperative period include ischemia; electrolyte abnormalities such as hypokalemia, hyperkalemia, hypomagnesemia, and hypocalcemia; pulmonary artery catheters; hypothermia and metabolic acidosis; antiarrhythmic medications; adrenergic medications and inotropes; and pacing wires. The treatment of ventricular arrhythmias includes cardioversion and defibrillation; identification and treatment of ischemia, including coronary artery bypass grafting, valvular surgery, and aortic root surgery; and the administration of lidocaine and amiodarone.