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Palliative Medicine
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
When a patient with advanced illness enters the dying phase (normally a day or so before death), all medication should be reviewed; all drugs should be stopped apart from those indicated for symptom control. The route of administration may need to be reviewed. Communication is vital; anticipate problems and changes in the patient's condition and explain them to the patient and their carers. Reassure them that the patient will be kept comfortable. Often it is appropriate to use a syringe pump to administer medications (Figure 16.2; Table 16.11).
Total Intravenous Anesthesia
Published in Michele Barletta, Jane Quandt, Rachel Reed, Equine Anesthesia and Pain Management, 2023
The potential disadvantages associated with TIVA include: Accumulation of the drug in the body tissues with prolonged anesthesia resulting delayed recovery.The potential need for a syringe pump to deliver precise volumes over time.There is currently no real-time method of monitoring plasma concentration of injectable agents, and therefore the infusion rate must be adjusted based on patient responses to depth assessment and known pharmacokinetic data. This is in contrast to inhalant agent use, where end tidal agent concentrations accurately reflect the amount of the inhalant circulating in the blood.
Female Methods
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
Another commercial model uses a peristaltic pump which draws solution from a reservoir and pumps it into the body (Figure 11.18). A slowly rotating pair of rollers squeeze a tube during rotation. The fluid column ahead of the point of contact of the roller and the tube advances and the fluid column behind the point of contact draws in the fluid from the reservoir. The advantage of this technique is that the reservoir and the pump tubing can be provided in prefilled form already sterilized. No further filling is required and so the possibility of entry of infectious organisms is reduced. Drug reservoir may be made sufficiently large to obviate the need for refilling during the course of the therapy. A disadvantage is that peristaltic pumps cannot deliver as accurate boluses of infúsate as the positive displacement syringe pumps. Even so the control obtainable is adequate for pulsatile therapy.
Microfluidics in drug delivery: review of methods and applications
Published in Pharmaceutical Development and Technology, 2023
Mutasem Rawas-Qalaji, Roberta Cagliani, Noor Al-hashimi, Rahma Al-Dabbagh, Amena Al-Dabbagh, Zahid Hussain
A simple microfluidic system consists of a pump, micromixer, followed by microchannels and quench zone as shown in Figure 1 (Shrimal et al. 2020). A reliable pump can be used to achieve continuous operation like a syringe pump, peristaltic pump, or high-performance liquid chromatography pump (HPLC). For small scale systems and to attain a precise and constant flow rate, the syringe pump is preferred. However, the main drawback of the syringe pump is its small capacity (<500 mL) that requires a frequent refill of the syringe. On the other hand, the HPLC pump works at high pressure and can give a higher flow rate than syringe pump, however, it cannot handle viscous fluids which cause a failure in the check value. For viscous and shear sensitive fluids, the peristaltic pump can be used in this case, but not when a precise and constant flow is needed (Shrimal et al. 2020).
Critical design parameters to develop biomimetic organ-on-a-chip models for the evaluation of the safety and efficacy of nanoparticles
Published in Expert Opinion on Drug Delivery, 2023
Mahmoud Abdelkarim, Luis Perez-Davalos, Yasmin Abdelkader, Amr Abostait, Hagar I. Labouta
The syringe pump is one of the most commonly used fluid injection devices in OOC experiments; it can maintain reasonably constant flow rates and almost constant shear stress on the cells. However, the syringe pump is a positive displacement pump that can change the pressure in the channel if any resistance appears to maintain a constant flow. In the latter case, the experimental conditions will not represent the physiological environment as the normal blood supply depends on the flow of fluid under a stable median blood pressure determined by systolic and diastolic values. Syringe pumps are also driven by stepper motors, which generate a pulsating flow that is most pronounced at low flow rates. In other words, at low flow rate values, the fluid injected into the chip will be more pulsating and not a continuous fluid flow. Therefore, it is preferable in this case to use constant pressure pumps when the pulsating flow is not recommended, as they provide more stable flow rates. By adjusting the applied pressure, we control the generated flow rate, whose value also depends on the resistance of the hydraulic channel. Therefore, it is advised that a flow sensor should also be integrated with the circulation to obtain an accurate flow rate.
Automated crude oil vapor inhalation exposure system
Published in Inhalation Toxicology, 2022
Walter McKinney, Mark C. Jackson, Brandon Law, Jeffrey S. Fedan
Namies (1984) describes several common methods of generating gas mixtures, and divides them into two main categories: static and dynamic. Static methods are based on mixing known amounts of test compounds and dilution components then storing them, often in a flexible container. Generation of the mixture is stopped when the flexible container is filled. Samples are then taken from the flexible container. Dynamic systems use continuous generation of the test compounds and the dilution components at known rates. Dynamic methods are preferred with inhalation exposures because they provide animals with a continuous air supply. There are several dynamic generation methods including the evaporation method and the injection method. The evaporation method is one in which dilution gas passes through or over a component to be vaporized. The evaporation method is not well suited for COV generation because of its complex mixture of volatile and semi-volatile components. If this method was used the most volatile components of the mixture would off-gas early during an exposure run, leaving less volatile components behind in the evaporation jar. This would result in changing compound levels during a 6-hour long exposure run. The injection method is one in which a volatile liquid is continuously introduced into a flowing dilution gas stream. Most injection methods use a syringe pump. Syringe pumps used for putting liquids into an air stream have been extensively used since 1950s for generation of standard gases in many applications, including inhalation toxicity studies (Sidney et al. 1994; Goldsmith et al. 2011).