Acute oxygenator occlusion in two cases of polycythemia vera: Bailout strategies.

Polycytemia vera (PV) is a rare myeloproliferative neoplasm associated with microcirculatory disturbances, thrombosis and bleeding. Patients suffering from PV have a high risk of perioperative adverse events, but the literature regarding on-pump procedures in PV patients is scarce. We report two cases of acute and severe oxygenator failure during cardiopulmonary bypass and present valid exit scenarios.

Extracorporeal cardiopulmonary resuscitation at the emergency department: A retrospective patient selection evaluation.

BACKGROUND: There is an increasing use of extracorporeal life support in refractory cardiac arrest. Recent studies highlighted the importance of an early and accurate patient selection for this invasive procedure. OBJECTIVES: The aim of this study was to retrospectively validate a six-criteria-screening-checklist (witnessed collapse, bystander-cardiopulmonary resuscitation/first medical contact <5 min, shockable, age <70 years, end tidal carbon dioxide >14 mmHg and pupils not anisocoric/distorted/mydriatic) as an early screening tool in patients treated with extracorporeal cardiopulmonary resuscitation (eCPR) at the emergency department. DESIGN: Retrospective observational study. SETTING/PATIENTS: All patients at least 18 years of age with nontraumatic cardiac arrest and without return of spontaneous circulation before eCPR treatment at our department between January 2013 and December 2018 were included in this retrospective observational study. INTERVENTION: No specific intervention was set in this observational study. MAIN OUTCOME MEASURES: Primary outcome was the rate of patients who fulfilled all criteria, secondary outcome was 30-day and 6-month survival in accordance with the criteria. RESULTS: Overall, data from a total of 92 patients were eligible for analyses. Out of these, 27 patients (29%) met all criteria. Patients, who fulfilled all criteria, showed significantly higher odds for 30-day survival [OR 6.0 (95% CI 1.78 to 20.19)] P = 0.004. Patients, who did not fulfil all criteria, showed significantly higher rates of early mortality after eCPR initiation [OR 4.57 (95% CI 1.69 to 12.37)] P = 0.003. CONCLUSION: Patients fulfilling all inclusion criteria showed higher rates of survival after eCPR. Our results affirm that there is a possibility and even an obvious necessity for early patient selection based on standardised criteria before eCPR treatment. Large randomised trials are urgently needed to answer this question accurately.

A Standardized Telephone Intervention Algorithm Improves the Survival of Ventricular Assist Device Outpatients.

Ventricular assist devices (VADs) are an established therapeutic option for patients with chronic heart failure. Continuous monitoring of VAD parameters and their adherence to guidelines are crucial to detect problems in an early stage to optimize outcomes. A telephone intervention algorithm for VAD outpatients was developed, clinically implemented and evaluated. During the phone calls, a structured inquiry of pump parameters, alarms, blood pressure, INR, body weight and temperature, exit-site status and heart failure symptoms was performed and electronically categorized by an algorithm into 5 levels of severity. VAD outpatient outcomes without (n = 71) and with bi-weekly telephone interviews in their usual care (n = 25) were conducted using proportional hazard Cox regression, with risk adjustment based on a propensity score model computed from demographics and risk factors. From February 2015 through October 2017, 25 patients (n = 3 HeartMate II, n = 4 HeartMate 3 and n = 18 HeartWare HVAD) underwent 637 telephone interventions. In 57.5% of the calls no problems were identified, 3.9% were recalled on the next day because of alarms. In 26.5% (n = 169), the VAD Coordinator had to refer to the physician due to elevated blood pressure (n = 125, >85 mm Hg), INR < 2.0 or > 4.0 (n = 24) or edema (n = 10), 11.9% of the calls led to a follow-up because of equipment or exit-site problems. Propensity-adjusted 2-year survival (89% vs. 57%, P = 0.027) was significantly higher for the telephone intervention group. Continuous, standardized communication with VAD outpatients is important for early detection of upcoming problems and leads to significantly improved survival.

Importance of linguistic details in alarm messages of ventricular assist devices.

PURPOSE: In the daily use of ventricular assist devices (VAD), and especially in emergency situations, an easy, self-explanatory handling of the peripheral components is essential to solving life-threatening situations, for non-experienced bystanders as well as professional staff members. It has been proven that displaying messages can significantly improve proper reactions. However, in the case we report, an accidental pump cable disconnection could not be solved without the assistance of the VAD coordinator.
 CASE REPORT: A long-term HeartWare® HVAD patient inadvertently disconnected himself from the pump, most probably due to a metabolically caused mental disorder, for which he had been readmitted to the hospital. Unluckily, the pump cable slipped beneath the bed sheet and the ward staff was not able to solve the problem. The staff who were involved claimed that the messages on the controller did not help them to resolve the difficulty. A comparison between the German and English texts revealed some ambivalence in the German wordings. 
 RESULTS: Laypersons were asked to respond to this situation in a simulated scenario, starting with the original alarm messages "VAD stopped"-"VAD gestoppt" and "Connect Driveline"-"Verb-Kabel anschl." If they were unable to solve the problem within 3 minutes, another translation was offered orally: "Pumpe steht" and "Pumpenkabel anschließen". None of the 5 test persons were able to respond correctly to the emergency situation with the original translation, but when provided with a modified translation, everybody solved the problem within 30 seconds.
 CONCLUSIONS: Even small linguistic differences can lead to critical differences in the usability and, thus, the safety of VAD peripherals. Detailed discussions with professional translators and/or practical tests of failure scenarios may optimize usability.

Investigation of hemodynamics in the assisted isolated porcine heart.

BACKGROUND: Currently, the interaction between rotary blood pumps (RBP) and the heart is investigated in silico, in vitro, and in animal models. Isolated and defined changes in hemodynamic parameters are unattainable in animal models, while the heart-pump interaction in its whole complexity cannot be modeled in vitro or in silico. AIM: The aim of this work was to develop an isolated heart setup to provide a realistic heart-pump interface with the possibility of easily adjusting hemodynamic parameters. METHODS: A mock circuit mimicking the systemic circulation was developed. Eight porcine hearts were harvested using a protocol similar to heart transplantation. Then, the hearts were resuscitated using Langendorff perfusion with rewarmed, oxygenated blood. An RBP was implanted and the setup was switched to the "working mode" with the left heart and the RBP working as under physiologic conditions. Both the unassisted and assisted hemodynamics were monitored. RESULTS: In the unassisted condition, cardiac output was up to 9.5 l/min and dP/dtmax ranged from 521 to 3621 mmHg/s at a preload of 15 mmHg and afterload of 70 mmHg. With the RBP turned on, hemodynamics similar to heart-failure patients were observed in each heart. Mean pump flow and flow pulsatility ranged from 0 to 11 l/min. We were able to reproduce conditions with an open and closed aortic valve as well as suction events. CONCLUSIONS: An isolated heart setup including an RBP was developed, which combines the advantages of in silico/vitro methods and animal experiments. This tool thus provides further insight into the interaction between the heart and an RBP.