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The Isolated, Coronary-Perfused, Right Ventricular Wall Preparation
Published in John H. McNeill, Measurement of Cardiac Function, 2020
Thane G. Maddaford, Hamid Massaeli, Grant N. Pierce
It is important to clean the tubing at the end of each working day with 0.1 N HC1 and 70% ethanol for at least 5 min each, followed by pumping deionized water through the system. Bacterial contamination can be a serious detriment to heart performance, particularly at the lower flow rates employed here. Tubing should be replaced completely in the entire perfusion system on at least a bimonthly basis. All other nonmetal fittings and stopcocks should be occasionally soaked overnight in 0.1 N HC1 or replaced. Metal parts in the perfusion system must be made of corrosion-proof metal, such as high quality stainless steel for clamps, and platinum or gold for stimulating electrodes. Surfaces can be coated with a nontoxic plastic or enamel coating for additional protection.
Bioengineering Aids to Reproductive Medicine
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
Besides carbon dioxide gas, other distending media are also used in hysteroscopy. Dextrose 5% in water is a medium readily available in hospitals. The sugar has the property of flocculating erythrocytes and so the medium mixes with blood less readily than saline. Viscosity is low and so leakage past the hysteroscope is a problem. Also spill over into the peritoneal cavity is a possibility but seldom leads to complications. The medium is well absorbed and does not produce post hysteroscopy discomfort. Delivery system is extremely simple. A blood pressure cuff is wrapped around a plastic infusion bag containing the solution. Plastic intravenous tubing leading from the bag is connected to the inflow channel of the hysteroscope. A stopcock in the inflow path helps to control the flow. When the pressure within the uterine cavity builds up, the flow rate can be increased by inflating the blood pressure cuff. The manometer connected to the cuff gives an approximate indication of pressure. Since the measurement is indirect and variable, parameters such as the rigidity of the bag wall, opening of the stopcock, and length and diameter of the connecting tubing may introduce significant difference between the cuff pressure and the intrauterine pressure. Too much reliance should not be put on the cuff pressure data.
Isolated, Perfused Microvessels
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Michael J. Davis, Lih Kuo, William M. Chilian, Judy M. Muller
Microvessels often fail to develop spontaneous tone because small leaks in the system have not been detected and the vessels are being chronically dilated by flow. These leaks can occur not only from untied side-branches, but also from loose connections to valves and pipette holders. If this problem is suspected, we suggest connecting the pipette system using plugged (heat-polished) pipettes, pressurizing the entire system, then systematically closing off parts of the system while monitoring pressure with a transducer. We find that pressure transducers often have small leaks and may require rigorous tightening or even custom gaskets to prevent leaks. Whenever possible, we use Hamilton 3-way valves rather than disposable stopcocks.
Dosing Errors Made by Paramedics During Pediatric Patient Simulations After Implementation of a State-Wide Pediatric Drug Dosing Reference
Published in Prehospital Emergency Care, 2020
John D. Hoyle, Glenn Ekblad, Tracy Hover, Alyssa Woodwyk, Richard Brandt, Bill Fales, Richard L. Lammers
Our simulations allowed us to observe a previously undescribed phenomenon for prehospital pediatric medication administration-entrainment of air into the administration syringe and administration of that air to the simulated patient. Although it is doubtful that the amount of air itself would be harmful, it still contributed to under dosing of medication, especially those given in small volume syringes (e.g., 1 mL). This phenomenon was observed when medications were drawn directly into an administration syringe and with transfer to a second syringe for dilution. The training EMS crews receive for dilution requires pushing out a set amount of saline from a pre-loaded 10-mL saline flush syringe, such that the volume matches the dilution volume in the PDR instructions, and then drawing up the entire volume of the supplied drug vial. Next a 3-way stopcock is affixed to the syringe with diluted drug and a smaller administration syringe (e.g., 1 mL or 3 mL) is attached to the stopcock. Diluted drug is then pushed into the administration syringe. An unintended consequence of this process is that the air in the stopcock, typically about 0.2–0.3 mL, is pushed into the administration syringe. In our simulations, this amount of air was rarely recognized or eliminated. A way to avoid this would be to prime the stopcock with diluted drug prior to attaching the administration syringe. Uniformly, this was not done.
Development of a hydrogen cyanide inhalation exposure system and determination of the inhaled median lethal dose in the swine model
Published in Inhalation Toxicology, 2018
Jillian M. Staugler, Michael C. Babin, M. Claire Matthews, Matthew K. Brittain, Mark R. Perry
The system was designed to operate in two modes, bypass mode and exposure mode. The operation modes were controlled by a manually operated two-position four-way stopcock-type™ control valve (Series 2010 A, Hans Rudolph, Inc., Shawnee, KS), hereafter referred to as a 4-way valve. For each exposure, the HCN concentration was allowed to stabilize while the system was in bypass mode, during which clean air was provided to the animal, and the HCN exposure atmosphere was exhausted to the chemical fume hood. Turning of the 4-way valve to exposure mode initiated animal exposures. Excess clean air and HCN was passively exhausted to the hood during both bypass and exposure modes, eliminating potential pressure differences within the system. The flow of air was delivered to the animal via a pull system controlled by the exhaust flow. Respiratory parameters were monitored before (baseline), during (challenge) and after (clean air washout) exposures. During exposures, the HCN concentration and animal weight were used to calculate the required inhaled volume needed to achieve the target inhaled dose. A schematic of the exposure system is presented in Figure 1.
Triolein emulsion enhances temozolomide brain delivery: an experimental study in rats
Published in Drug Delivery, 2021
Won-Bae Seung, Seung Heon Cha, Hak Jin Kim, Seon Hee Choi, Juho Lee, Dongmin Kwak, Hyunwoo Kim, Jin-Wook Yoo, Yong-Woo Kim, Sang Kyoon Kim, Da-Sol Lee
TMZ, triolein, and trypan blue were purchased from Sigma-Aldrich (St. Louis, MO, USA). Silk and ketamine hydrochloride were purchased from Ailee (Busan, Korea) and Huons (Gyeonggi-do, Korea), respectively, whereas Rompun (xylazine) was purchased from Bayer Korea (Seoul, Korea). Dimethyl sulfoxide (DMSO) was purchased from Daejung (Siheung-si, Korea). Intravenous (IV) catheters and 2-mL syringes were purchased from Dukwoo Medical Co., Ltd. (Gyeonggi-do, Korea) and Korea Vaccine (Seoul, Korea), respectively. The three-way stopcock was purchased from Becton Dickinson (Franklin Lakes, NJ, USA).