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Congenital Heart Disease in Pregnancy
Published in Afshan B. Hameed, Diana S. Wolfe, Cardio-Obstetrics, 2020
The first definitive surgical repairs for D-TGA were the Senning [18] and Mustard [19] atrial switch procedures. The atrial switch procedure is a physiologic correction that uses surgically placed baffles to redirect systemic venous return across the atrial septum to the left atrium, thus allowing deoxygenated blood to flow to the pulmonary artery; the pulmonary venous baffle directs the pulmonary venous return rightward across the atrial septum to the right atrium, thus allowing oxygenated blood to travel to the aorta. In the atrial switch procedure, the right ventricle thus serves as the systemic ventricle, pumping oxygenated blood to the aorta, while the left ventricle is the subpulmonary ventricle, pumping deoxygenated blood to the pulmonary artery. Long-term sequelae of the atrial switch procedures include baffle stenoses which can increase pressures in the systemic or pulmonary veins, baffle leaks which would result in an atrial level shunt, systemic right ventricle systolic and diastolic dysfunction, tricuspid regurgitation, atrial tachyarrhythmias, and sinus node dysfunction.
Open Cultivation Systems and Closed Photobioreactors for Microalgal Cultivation and Biomass Production
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
C.K. Madhubalaji, Ajam Shekh, P.V. Sijil, Sandeep Mudliar, Vikas Singh Chauhan, Ravi Sarada, Ambati Ranga Rao, Gokare A. Ravishankar
Stirred tank photobioreactors (Figure 15.9) are the most common and conventional photobi oreactors. Impellers of various size and shapes are used for mechanical agitation. Baffles are used to reduce the vortex. The CO2 (v/v) is bubbled from the bottom of the reactor. The light is provided by externally illuminated fluorescent lamps. The disadvantage of the stirred tank reactor is that it has a lower surface area to volume ratio which in turns decreases light harvesting efficiency. Due to this reason, the stirred tank photobioreactors are less explored, and its use is limited for microalgae cultivation. Pohl (1988) tried to overcome this disadvantage by providing a fluorescent lamp internally to the culture. The use of optical fibers is also in practice but it is known to create an impediment in the pattern of culture mixing (Pohl 1988). Its use for CO2 utilization by microalgae is restricted due to drawbacks like low surface area to volume ratio, which reduces light harvesting efficiency (Franco-Lara et al. 2006), and another one is high shear stress. The major element of a stirred tank photobioreactor is the impeller or agitator, which is responsible for homogenous mixing, aeration, and better heat and mass transfer (Doran 2013).
Interventional cardiac catheterisation in adults with congenital heart disease
Published in Ever D. Grech, Practical Interventional Cardiology, 2017
Hussam S Suradi, Ziyad M Hijazi
The success of the Senning and Mustard type venous switches for the treatment of the transposition of the great arteries has led to the long-term survival of many of these patients. These intra-atrial surgical baffles allow the systemic venous return to flow through the atria and cross the mitral valve to fill the left ventricle. The left ventricle then pumps the blood to the pulmonary arteries. The fully oxygenated blood returns to the left atrium and flows over the other side of the baffle to the right ventricle and out the aorta. A number of these patients have been noted to have progressive obstruction of these venous baffles. The surgical results of repair of the baffles obstruction were not favourable, therefore, trans-catheter therapy with balloon dilation and stenting emerged as the preferred therapy of choice.32,33 Complete obstructions can be perforated and residual narrowings treated using single or multiple stents (Figure 36.12). Re-dilatation for neointimal hyperplasia induced stenosis following stent placement is also successful.34 Furthermore, conduit leaks can be treated percutaneously via the use of covered stents or occlusion devices.
Canalplasty using underwater bone drilling in transcanal endoscopic myringoplasty for patients with a narrow external auditory canal
Published in Acta Oto-Laryngologica, 2022
Quanming Zhang, Lue Zhang, Nan Zeng, Jing Hu, Shuo Li, Chunsheng Gao, Qiong Yang
A problem associated with the underwater drilling technique is that the tympanomeatal flap might be floated by continuous saline irrigation and entangled and torn by the rotating bur. In the series of operations in this study, after the TM was completely avulsed from the malleus handle, the surgeon tried to tuck the tympanomeatal flap into the protympanum and place an elastic thin oval metal baffle of an appropriate size on the outside of the flap to fix and protect it. The results showed that no tissue injury by the bur or baffle occurred. Notably, an appropriate size of the baffle is of great importance: A baffle that is too small, cannot be firmly fixed, while a baffle that is too large, may cause cutting damage to the chorda tympani or even result in dislocation of the ossicular chain under undue pressure. Therefore, the safety of this kind of baffle requires observation in more cases, and a more ideal method for protecting the tympanomeatal flap needs to be further explored.
Impaired neuromuscular function by conjoint actions of organophosphorus insecticide metabolites omethoate and cyclohexanol with implications for treatment of respiratory failure
Published in Clinical Toxicology, 2021
Kosala N. Dissanayake, Robert Chang-Chih Chou, Adrian Thompson, Filip Margetiny, Charlotte Davie, Scott McKinnon, Vishwendra Patel, Lester Sultatos, Joseph J. McArdle, Richard E. Clutton, Michael Eddleston, Richard R. Ribchester
For isolation of nerve-muscle preparations, mice were sacrificed in accordance with UK Home Office Schedule 1, by anaesthetic overdose followed by cervical dislocation. Nerve-muscle preparations of flexor digitorum brevis (FDB), hemidiaphragm, or triangularis sterni (TS) [34,37] were promptly dissected and maintained in mammalian physiological saline (MPS) with the following composition (mM): Na+ (158); K+ (5); Ca2+ (2); Mg2+ (1); Cl− (169); glucose (5); HEPES (5); pH 7.2–7.4. Solutions were bubbled with air for at least 20 min. Most experiments were conducted at room temperature (19–25 °C). Dimethoate, omethoate, cyclohexanone, cyclohexanol or xylene (all Sigma-Aldrich) were added directly from aqueous stock solutions to bathing solutions to give the concentrations required. Aliquots (10–100 µl) were either pipetted directly and thoroughly mixed into MPS in the recording chamber to the required concentration, or solutions containing the required final concentration in 50 ml volumes were rapidly exchanged with the solution in the recording chamber (volume approximately 10 ml) using coupled back-to-back 20–50 ml syringes connected to ports at opposite ends of the chamber. Baffles built into the chamber facilitated laminar flow and complete solution exchange occurred within 5–20 s.
Percutaneous techniques for treatment of tricuspid valve dysfunction in congenital heart disease – an emerging therapy
Published in Expert Review of Cardiovascular Therapy, 2021
Dysfunction of systemic TV in ccTGA or after Senning or Mustard operation is a more complex situation. After the initial atrial switch operation, most patients do well for some years; however, in some RV dysfunction with dilation and consecutive TVR occurs. Surgical tricuspid valve replacement, if indicated, is a high-risk procedure also bioprosthesis in this position has a limited durability [7,8]. Percutaneous tricuspid valve-in-valve implantation is a relatively new treatment option for these patients. For transcutaneous valve delivery in this anatomy, the atrial baffle has to be perforated. If a baffle has been formed by synthetic material as it is done in the Mustard procedure, the perforation could have been technically more demanding. Nevertheless, even in a Senning anatomy, a balloon dilatation of the septum can be appropriate before advancing a big sheath across the baffle. If in the future inevitable valve dysfunction reoccurs, surgical valve replacement with a mechanical prosthesis needs to be discussed [9].