The latest medical research on Transplant Pulmonology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about transplant pulmonology gathered by our medical AI research bot.

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Meropenem extraction by ex vivo extracorporeal life support circuits.

Journal of Extra-Corporeal Technology

Meropenem is a broad-spectrum carbapenem-type antibiotic commonly used to treat critically ill patients infected with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. As many of these patients require extracorporeal membrane oxygenation (ECMO) and/or continuous renal replacement therapy (CRRT), it is important to understand how these extracorporeal life support circuits impact meropenem pharmacokinetics. Based on the physicochemical properties of meropenem, it is expected that ECMO circuits will minimally extract meropenem, while CRRT circuits will rapidly clear meropenem. The present study seeks to determine the extraction of meropenem from ex vivo ECMO and CRRT circuits and elucidate the contribution of different ECMO circuit components to extraction.

Standard doses of meropenem were administered to three different configurations (n = 3 per configuration) of blood-primed ex vivo ECMO circuits and serial sampling was conducted over 24 h. Similarly, standard doses of meropenem were administered to CRRT circuits (n = 4) and serial sampling was conducted over 4 h. Meropenem was administered to separate tubes primed with circuit blood to serve as controls to account for drug degradation. Meropenem concentrations were quantified, and percent recovery was calculated for each sample.

Meropenem was cleared at a similar rate in ECMO circuits of different configurations (n = 3) and controls (n = 6), with mean (standard deviation) recovery at 24 h of 15.6% (12.9) in Complete circuits, 37.9% (8.3) in Oxygenator circuits, 47.1% (8.2) in Pump circuits, and 20.6% (20.6) in controls. In CRRT circuits (n = 4) meropenem was cleared rapidly compared with controls (n = 6) with a mean recovery at 2 h of 2.36% (1.44) in circuits and 93.0% (7.1) in controls.

Meropenem is rapidly cleared by hemodiafiltration during CRRT. There is minimal adsorption of meropenem to ECMO circuit components; however, meropenem undergoes significant degradation and/or plasma metabolism at physiological conditions. These ex vivo findings will advise pharmacists and physicians on the appropriate dosing of meropenem.

Development of new colloid osmotic pressure measurement method using ultrafiltration membrane during cardiopulmonary bypass.

Journal of Extra-Corporeal Technology

Clinical practice of measuring colloid osmotic pressure (COP) was abandoned after correcting hypoosmolarity did not improve overall patient outcomes. However, the use of albumin and colloidal solutions has contributed to maintaining intraoperative and postoperative fluid balance at lower levels. Reduced perioperative fluid balance is consistently reported to have positive effects on clinical outcomes. Priming solutions for cardiopulmonary bypass typically include colloids; however, the optimal type of priming solution has not yet been determined. Stricter COP management may further improve postoperative courses. To achieve this, the widespread adoption of a measurement method suitable for COP monitoring during cardiopulmonary bypass is required.

A test circuit was made which measured COP using an ultrafiltration membrane method based on the changes in hydrostatic pressure that occurs across a semipermeable membrane. We then compared the measurements obtained using this method with colloidal osmometer measurements.

COP measurements were obtained for a total of 100 tests (10 times each for 10 test solutions). The evaluation parameters included simultaneous reproducibility, correlation with the colloid osmometer, and measurement time. The results demonstrated high accuracy of the ultrafiltration membrane method, simultaneous reproducibility within 3%, a high positive correlation with the colloid osmometer (correlation coefficient: R2 = 0.99; p < 0.01), and equal time required for measurement.

Measuring COP using ultrafiltration membranes solves problems within existing measurement methods. Although further improvements in the method are necessary, it has implications for future research and clinical applications.

Impact of pre-bypass ultrafiltration on prime values and clinical outcomes in neonatal and infant cardiopulmonary bypass.

Journal of Extra-Corporeal Technology

A standard blood prime for cardiopulmonary bypass (CPB) in congenital cardiac surgery may possess non-physiologic values for electrolytes, glucose, and lactate. Pre-bypass Ultrafiltration (PBUF) can make these values more physiologic and standardized prior to bypass initiation. We aimed to determine if using PBUF on blood primes including packed red blood cells and thawed plasma would make prime values more predictable and physiologic. Additionally, we aimed to evaluate whether the addition of PBUF had an impact on outcome measures.

Retrospective review of consecutive patients ≤ 1 year of age undergoing an index cardiac operation on CPB between 8/2017 and 9/2021. As PBUF was performed at the perfusionists' discretion, a natural grouping of patients that received PBUF vs. those that did not occur. Differences in electrolytes, glucose, and lactate were compared at specific time points using Fisher's exact test for categorical variables and the Wilcoxon rank sum test for continuous variables. Clinical outcomes were also assessed.

In both cohorts, the median age at surgery was 3 months and 47% of patients were female; 308/704 (44%) of the PBUF group and 163/414 (39%) of the standard prime group had at least one preoperative risk factor. The proportion of PBUF circuits which demonstrated more physiologic values for glucose (318 [45%]), sodium (434, [62%]), potassium (688 [98%]), lactate (612 [87%]) and osmolality (595 [92%]) was significantly higher when compared to standard prime circuit levels for glucose (8 [2%]), sodium (13 [3%], potassium (150 [36%]), lactate (56 [13%]) and osmolality (23 [6%]) prior to CPB initiation. There were no differences in clinical outcomes or rates of major adverse events between the two cohorts.

PBUF creates standardized and more physiologic values for electrolytes, glucose, and lactate before the initiation of bypass without significant impacts on in-hospital outcomes.

Building an Extracorporeal Cardiopulmonary Resuscitation Program at a High-volume Extracorporeal Membrane Oxygenation Center.

Journal of Extra-Corporeal Technology

Extracorporeal Cardiopulmonary Resuscitation (ECPR) is an emerging approach to cardiac arrest. We present two contrasting cases from a high-volume ...

An in vitro comparison of intra-operative isohemagglutinin and human leukocyte antigen removal techniques in pediatric heart transplantation.

Journal of Extra-Corporeal Technology

Highly sensitized pediatric patients awaiting heart transplantation experience longer wait times and thus higher waitlist mortality. Similarly, children less than 2 years of age have increased waitlist times and mortality when compared to their older peers. To improve the likelihood of successful transplantation in these patients, various strategies have been utilized, including peri-operative plasmapheresis. However, limited data exists comparing plasmapheresis techniques for antibody reduction. This study's aim was to compare the in vitro magnitude of isohemagglutinin titers (IT) and human leukocyte antigen (HLA) antibody removal and the time required between membrane-based plasmapheresis (MP) and centrifuge-based plasmapheresis (CP) incorporated into the extracorporeal (EC) circuit.

Two MP (Prismaflex) and two CP (Spectra Optia, Terumo BCT) circuits were incorporated into four separate EC circuits primed with high titer, highly sensitized type O donor whole blood. Assays were performed to determine baseline IT and anti-HLA antibodies and then at 30-minute increments until completion of the run (two plasma volume exchanges) at two hours.

There was a decrease in anti-A and anti-B IgM and IgG titers with both MP and CP. Mean anti-A and anti-B titer reduction was by 4.625 titers (93.7% change) and 4.375 titers (93.8% change) using MP and CP, respectively. At 2 h of apheresis, CP reduced 62.5% of all ITs to ≤ 1:4, while MP reduced 50% of ITs to ≤ 1:4. Additionally, reduction of anti-HLA class II antibody to mean fluorescence intensity (MFI) <3000 was achieved with both MP and CP. At 2 h of apheresis, CP reduced MFI by 2-3.5 fold and MP reduced MFI by 1.7-2.5 fold. Both demonstrated similar hemolytic and thrombotic profiles.

In this in vitro plasmapheresis model of IT and anti-HLA antibody reduction, both MP and CP incorporated into the EC circuit can be used quickly and effectively to reduce circulating antibodies. While CP may have some greater efficiency, further study is necessary to verify this in vivo.

Direct and continuous dosing of propofol can saturate Ex vivo ECMO circuit to improve propofol recovery.

Journal of Extra-Corporeal Technology

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary bypass device that provides life-saving complete respiratory and cardiac support in patients with cardiorespiratory failure. The majority of drugs prescribed to patients on ECMO lack a dosing strategy optimized for ECMO patients. Several studies demonstrated that dosing is different in this population because the ECMO circuit components can adsorb drugs and affect drug exposure substantially. Saturation of ECMO circuit components by drug disposition has been posited but has not been proven. In this study, we have attempted to determine if propofol adsorption is saturable in ex vivo ECMO circuits.

We injected ex vivo ECMO circuits with propofol, a drug that is highly adsorbed to the ECMO circuit components. Propofol was injected as a bolus dose (50 μg/mL) and a continuous infusion dose (6 mg/h) to investigate the saturation of the ECMO circuit.

After the bolus dose, only 27% of propofol was recovered after 30 minutes which is as expected. However, >80% propofol was recovered after the infusion dose which persisted even when the infusion dose was discontinued.

Our results suggest that if ECMO circuits are dosed directly with propofol, drug adsorption can be eliminated as a cause for altered drug exposure. Field of Research: Artificial Lung/ECMO.

ECPR for prolonged Pediatric Cardiac Arrest, an outcome without major neurological compromise.

Journal of Extra-Corporeal Technology

Pediatric in-hospital cardiac arrest (IHCA) has been reported in 1-3% of pediatric intensive care unit (ICU) admissions and up to 6% of children ad...

Fifth-time redo mitral valve replacement via right thoracotomy under systemic hyperkalemia cardiopulmonary bypass without aortic cross-clamp.

Journal of Extra-Corporeal Technology

The surgical management of prosthetic valvular endocarditis (PVE) can be challenging. We report a case of a 46-year-old female patient who had a hi...

Central ECMO cannulation for severe dihydropyridine calcium channel blocker overdose.

Journal of Extra-Corporeal Technology

Calcium channel blocker (CCB) toxicity carries a high mortality and is the sixth most fatal drug class reported to US poison centers. Amlodipine ov...

Our initial experience of monitoring the autoregulation of cerebral blood flow during cardiopulmonary bypass.

Journal of Extra-Corporeal Technology

Cerebral blood flow (CBF) is believed to be relatively constant within an upper and lower blood pressure limit. Different methods are available to monitor CBF autoregulation during surgery. This study aims to critically analyze the application of the cerebral oxygenation index (COx), one of the commonly used techniques, using a reference to data from a series of clinical registrations.

CBF was monitored using near-infrared spectroscopy, while cerebral blood pressure was estimated by recordings obtained from either the radial or femoral artery in 10 patients undergoing cardiopulmonary bypass. The association between CBF and blood pressure was calculated as a moving continuous correlation coefficient. A COx index > 0.4 was regarded as a sign of abnormal cerebral autoregulation (CA). Recordings were examined to discuss reliability measures and clinical feasibility of the measurements, followed by interpretation of individual results, identification of possible pitfalls, and suggestions of alternative methods.

Monitoring of CA during cardiopulmonary bypass is intriguing and complex. A series of challenges and limitations should be considered before introducing this method into clinical practice.

A multipurpose Extracorporeal Life Support Circuit: a concept for multiorgan transplant and circulatory support service Healthcare provider.

Journal of Extra-Corporeal Technology

The demand for efficient and adaptable life support systems in the field of Extracorporeal Life Support (ECLS) is steadily increasing. To meet this...

Pre-transplant factors associated with mortality after lung transplantation in cystic fibrosis: A systematic review and meta-analysis.

J Cyst Fibros

Mortality risk stratification is essential in lung transplantation (LTx) to allow listing, prioritization and mitigating strategies. In cystic fibrosis (CF) patients, predictors of post-LTx mortality are not established.

For this systematic review and meta-analysis, seven databases were searched until January 3, 2018 to identify predictors of post-LTx mortality in CF. We excluded studies of multi-organ transplantation, re-transplantation and graft survival. For multiple studies assessing the same population during overlapping time-periods, the largest one was analyzed. Risk of bias was assessed with the Newcastle-Ottawa scale (NOS). Pooled hazard ratios were calculated using random-effects models.

Fifty-four studies were included in the systematic review and 11 studies in the meta-analyses (low-to-moderate bias risk, NOS score ≥ 5). Among 10 factors assessed in the meta-analysis, B. cepacia complex (BCC) (N = 1451, unadjusted HR = 2.35, 95%CI:1.80-3.06; I2 = 20.4% and adjusted HR = 2.49, 95%CI:1.74-3.57; I2 = 46.2%) and ascending chronological year of LTx (N = 4207, unadjusted HR = 0.98, 95%CI:0.97-0.98, I2 = 4.8%) were predictors of post-LTx mortality. Male gender (N = 2903, adjusted HR = 1.12, 95%CI:1.0-1.26, I2 = 0%) and age in adults (N = 3677, unadjusted HR = 0.99, 95%CI:0.97-1.00; I2 = 64.1% and N = 2605, adjusted HR = 0.98, 95%CI:0.97-0.99; I2 = 34.3%) had borderline significant associations with post-LTx mortality. P. aeruginosa colonization, forced expiratory volume in one second (FEV1), pulmonary hypertension, body mass index (BMI), pancreatic insufficiency and CF-related diabetes (CFRD) were not predictors of mortality.

BCC was associated with a higher post-LTx mortality whereas FEV1, pulmonary hypertension, BMI, CFRD and female gender were not associated with post-LTx mortality. These findings indicate that CF-specific risk estimates of post-LTx mortality should be considered.