Does conventional intra-aortic balloon pump trigger timing produce optimal hemodynamic effects in vivo?

Purpose The intra-aortic balloon pump (IABP) provides circulatory support through counterpulsation. The hemodynamic effects of the IABP may vary with assisting frequency and depend on IAB inflation/deflation timing. We aimed to assess in vivo the IABP benefits on coronary, aortic, and left ventricular hemodynamics at different assistance frequencies and trigger timings. Methods Six healthy, anesthetized, open-chest sheep received IABP support at 5 timing modes (EC, LC, CC, CE, CL, corresponding to early/late/conventional/conventional/conventional inflation and conventional/conventional/conventional/early/late deflation, respectively) with frequency 1:3 and 1:1. Aortic (Qao) and coronary (Qcor) flow, and aortic (Pao) and left ventricular (PLV) pressure were recorded simultaneously, with and without IABP support. Integrating systolic Qao yielded stroke volume (SV). Results EC at 1:1 produced the lowest end-diastolic Pao (59.5 ± 7.8 mmHg [EC], 63.4 ± 11.1 mmHg [CC]), CC at 1:1 the lowest systolic PLV (69.1 ± 6.5 mmHg [CC], 76.4 ± 6.5 mmHg [control]), CC at 1:1 the highest SV (88.5 ± 34.4 ml [CC], 76.6 ± 31.9 ml [control]) and CC at 1:3 the highest diastolic Qcor (187.2 ± 25.0 ml/min [CC], 149.9 ± 16.6 ml/min [control]). Diastolic Pao augmentation was enhanced by both assistance frequencies alike, and optimal timings were EC for 1:3 (10.4 ± 2.8 mmHg [EC], 6.7 ± 3.8 mmHg [CC]) and CC for 1:1 (10.8 ± 6.7 mmHg [CC], −3.0 ± 3.8 mmHg [control]). Conclusions In our experiments, neither a single frequency nor a single inflation/deflation timing, including conventional IAB timing, has shown superiority by uniformly benefiting all studied hemodynamic parameters. A choice of optimal frequency and IAB timing might need to be made based on individual patient hemodynamic needs rather than as a generalized protocol

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

Safety assessment of open appendectomies for complicated acute appendicitis in children: a comparison of trainees and specialists

Purpose: The aim of this study was to compare the outcome of children with complicated acute appendicitis (CAA) who underwent open appendectomy (OA) performed either by trainees under the direct supervision of an SPS, or an SPS. Methods: Two hundred thirty eight patients with CAA were reviewed operated on either by a junior trainee (JT) or a senior trainee (ST) under the direct supervision of an SPS or by an SPS. The outcome measures were the overall rate of complications, operative time (OT), length of hospital stay (LHS) and 30-day readmission rate. Results: No statistical differences were observed between the three groups regarding the overall complication rates and 30-day readmission rate. Although, no statistical differences were observed in the mean OT between the three groups, the mean OT for perforated appendicitis (PA) performed by JTs was significantly longer than when performed by SPSs (p 0.012). Furthermore, there was a statistically significant difference between JTs and SPSs in terms of LHS for patients with PA (p 0.028). Conclusion: This study suggests that no statistical differences were observed between the supervised trainees and SPSs regarding the overall complication rate and 30-readmission rate when they performed OA for GA or PA except of a longer OT and LHS for PA performed by JTs. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

Three-dimensional versus two-dimensional laparoscopic surgery for colorectal cancer: Systematic review and meta-analysis

Background/Aim: Three-dimensional (3D) laparoscopy is being steadily adopted instead of two-dimensional (2D) for various procedures. Our aim was to compare the outcomes between 2D and 3D laparoscopic procedures for colorectal cancer in order to ascertain the safety, efficacy and potential advantages of 3D imaging systems. Materials and Methods: A systematic database search was conducted in March 2019. Comparative studies reporting clinical outcomes between patients undergoing elective colorectal procedures using either 2D or 3D laparoscopic equipment were eligible. Results: Six studies were selected, including 614 patients in total. Minor reduction in operative time, similar blood loss and increased number of harvested lymph nodes was noted for the 3D group. There was no difference for conversion to open surgery, time to flatus, postoperative hospital stay or postoperative complications. Conclusion: 3D Laparoscopic surgery for colorectal cancer may result in reduction of operative time and higher lymph node yields, leading to improved survival. © 2020 International Institute of Anticancer Research. All rights reserved

Hemodynamic comparison of polyurethane trileaflet and tissue heart valve prostheses

In this paper, a hemodynamic comparison of two polyurethane trileaflet heart valve prostheses with currently available biological tissue valve prostheses are made. The valves, sutured to a valve mounting ring are incorporated in a mock circulatory system and tests are performed at various heart rates to cover physiological states from rest to exercise. The measurements included the transvalvular pressure drop, percent regurgitation and the valve opening area. For comparable size valves, the functional characteristics of the polyurethane valves compare favorably with those of the bioprostheses. Such comparisons are valuable in improvements in the design of synthetic valves which can be manufactured relatively inexpensively. With improved designs to overcome problems with fatigue failure and leaflet calcification, polyurethane trileaflet valves can be a viable alternative as heart valve prostheses as well as valve of choice in the artificial heart and circulatory assist devices

In Vitro Comparison of Velocity Profiles and Turbulent Shear Distal to Polyurethane Trileaflet and Pericardial Prosthetic Valves

Abstract: A comparative study of flow dynamics past bi‐omer trileaflet valves and a pericardial bioprosthetic valve under steady and physiological pulsatile flow conditions in vitro is reported in this paper. The velocity profiles and the turbulent shear stresses distal to the valves were measured using laser Doppler anemometry. The authors\u27 results showed that the velocity profiles distal to the trileaflet valves were similar to that measured distal to the pericardial valve. Higher magnitudes of absolute turbulent shear stresses were measured distal to the synthetic valves in comparison to the pericardial valves. However, when the stresses were nondimension‐alized with respect to the orifice diameter at the inlet aspect, the stresses were comparable for all of the three valves. With design modifications to increase the orifice diameter at the inlet aspect of the polyurethane valves, the turbulent stresses distal to the valves can be minimized. Such in vitro studies on the flow dynamics past the polyurethane valves can provide information towards design changes to improve the performance characteristics of these valves. Polyurethane valves with flow characteristics comparable to the pericardial valves can be manufactured relatively inexpensively compared to mechanical or tissue valve prosthesis. Hence, the synthetic valves may be a viable alternative for short‐term use in total artificial heart devices as a bridge to transplant. © 1989 International Society for Artificial Organ

Hemodynamic comparisons of polyurethane trileaflet and bioprosthetic heart valves

Hemodynamic comparison of two polyurethane prosthetic heart valves with a bioprosthetic valve is presented. The valves were incorporated in a pulse duplicator simulating physiologic pulsatile flow, and comparisons between the valves were made on the transvalvular pressure drop, percent regurgitation, valve orifice area, rate of opening and closing as well as the performance index. The results showed that the functional characteristics of the polyurethane valves compared favorably with that of the bioprosthetic valve. The polyurethane valve can be a viable and inexpensive alternative, especially for short-term use in a total artificial heart as a bridge to transplant