Pump thrombosis and dynamic outflow graft compression: complications in left ventricular assist device therapy.

Over the past decade, left ventricular assist device (VAD) therapy has become more prevalent and increasingly safe. Severe complications, such as VAD pump thrombosis and outflow graft obstruction, are rare, yet still associated with high morbidity and mortality. Clinical presentation, VAD alarm and log files, laboratory analysis, and non-invasive cardiac imaging are crucial for establishing the correct diagnosis and determining clinical management. Early intervention is critical to prevent adverse cardiac remodelling or VAD pump failure.

An in vitro lung model to assess true shunt fraction by multiple inert gas elimination.

The Multiple Inert Gas Elimination Technique, based on Micropore Membrane Inlet Mass Spectrometry, (MMIMS-MIGET) has been designed as a rapid and direct method to assess the full range of ventilation-to-perfusion (V/Q) ratios. MMIMS-MIGET distributions have not been assessed in an experimental setup with predefined V/Q-distributions. We aimed (I) to construct a novel in vitro lung model (IVLM) for the simulation of predefined V/Q distributions with five gas exchange compartments and (II) to correlate shunt fractions derived from MMIMS-MIGET with preset reference shunt values of the IVLM. Five hollow-fiber membrane oxygenators switched in parallel within a closed extracorporeal oxygenation circuit were ventilated with sweep gas (V) and perfused with human red cell suspension or saline (Q). Inert gas solution was infused into the perfusion circuit of the gas exchange assembly. Sweep gas flow (V) was kept constant and reference shunt fractions (IVLM-S) were established by bypassing one or more oxygenators with perfusate flow (Q). The derived shunt fractions (MM-S) were determined using MIGET by MMIMS from the retention data. Shunt derived by MMIMS-MIGET correlated well with preset reference shunt fractions. The in vitro lung model is a convenient system for the setup of predefined true shunt fractions in validation of MMIMS-MIGET.

For and against Organ Donation and Transplantation: Intricate Facilitators and Barriers in Organ Donation Perceived by German Nurses and Doctors.

Background. Significant facilitators and barriers to organ donation and transplantation remain in the general public and even in health professionals. Negative attitudes of HPs have been identified as the most significant barrier to actual ODT. The purpose of this paper was hence to investigate to what extent HPs (physicians and nurses) experience such facilitators and barriers in ODT and to what extent they are intercorrelated. We thus combined single causes to circumscribed factors of respective barriers and facilitators and analyzed them for differences regarding profession, gender, spiritual/religious self-categorization, and self-estimated knowledge of ODT and their mutual interaction. Methods. By the use of questionnaires we investigated intricate facilitators and barriers to organ donation experienced by HPs (n = 175; 73% nurses, 27% physicians) in around ten wards at the University Hospital of Munich. Results. Our study confirms a general high agreement with the importance of ODT. Nevertheless, we identified both facilitators and barriers in the following fields: (1) knowledge of ODT and willingness to donate own organs, (2) ethical delicacies in ODT, (3) stressors to handle ODT in the hospital, and (4) individual beliefs and self-estimated religion/spirituality. Conclusion. Attention to the intricacy of stressors and barriers in HPs continues to be a high priority focus for the availability of donor organs.

Multi frequency phase fluorimetry (MFPF) for oxygen partial pressure measurement: ex vivo validation by polarographic clark-type electrode.

BACKGROUND: Measurement of partial pressure of oxygen (PO2) at high temporal resolution remains a technological challenge. This study introduces a novel PO2 sensing technology based on Multi-Frequency Phase Fluorimetry (MFPF). The aim was to validate MFPF against polarographic Clark-type electrode (CTE) PO2 measurements. METHODOLOGY/PRINCIPAL FINDINGS: MFPF technology was first investigated in N = 8 anaesthetised pigs at FIO2 of 0.21, 0.4, 0.6, 0.8 and 1.0. At each FIO2 level, blood samples were withdrawn and PO2 was measured in vitro with MFPF using two FOXY-AL300 probes immediately followed by CTE measurement. Secondly, MFPF-PO2 readings were compared to CTE in an artificial circulatory setup (human packed red blood cells, haematocrit of 30%). The impacts of temperature (20, 30, 40°C) and blood flow (0.8, 1.6, 2.4, 3.2, 4.0 L min(-1)) on MFPF-PO2 measurements were assessed. MFPF response time in the gas- and blood-phase was determined. Porcine MFPF-PO2 ranged from 63 to 749 mmHg; the corresponding CTE samples from 43 to 712 mmHg. Linear regression: CTE = 15.59+1.18*MFPF (R(2) = 0.93; P<0.0001). Bland Altman analysis: meandiff 69.2 mmHg, rangediff -50.1/215.6 mmHg, 1.96-SD limits -56.3/194.8 mmHg. In artificial circulatory setup, MFPF-PO2 ranged from 20 to 567 mmHg and CTE samples from 11 to 575 mmHg. Linear regression: CTE = -8.73+1.05*MFPF (R(2) = 0.99; P<0.0001). Bland-Altman analysis: meandiff 6.6 mmHg, rangediff -9.7/20.5 mmHg, 1.96-SD limits -12.7/25.8 mmHg. Differences between MFPF and CTE-PO2 due to variations of temperature were less than 6 mmHg (range 0-140 mmHg) and less than 35 mmHg (range 140-750 mmHg); differences due to variations in blood flow were less than 15 mmHg (all P-values>0.05). MFPF response-time (monoexponential) was 1.48±0.26 s for the gas-phase and 1.51±0.20 s for the blood-phase. CONCLUSIONS/SIGNIFICANCE: MFPF-derived PO2 readings were reproducible and showed excellent correlation and good agreement with Clark-type electrode-based PO2 measurements. There was no relevant impact of temperature and blood flow upon MFPF-PO2 measurements. The response time of the MFPF FOXY-AL300 probe was adequate for real-time sensing in the blood phase.