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Clinical Workflows Supported by Patient Care Device Data
Published in John R. Zaleski, Clinical Surveillance, 2020
The purpose of the lungs is to extract oxygen and at the same expel carbon dioxide with each breath. During CABG surgery, the patient is administered a series of drugs that have the effect of depressing respiratory and cardiovascular function. Because of their effect, these drugs will cause the cessation of spontaneous breathing below life-sustaining levels. Two such indicators of life-sustaining lung function are respiration rate, fR, and tidal volume, Vt (the volume of air inspired in a normal breath). Respiration rate is measured in terms of the number of breaths per minute. The tidal volume is a measure of the amount of air taken into the lungs during the course of a normal breath. In a resting state, the typical human breathes effortlessly at about 12 breaths per minute and a tidal volume commensurate with physiological characteristics associated with the size and weight
Chapter 17 Respiratory Function
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
The lungs are not emptied completely each time air is exhaled, indeed when a person is resting only about 0.5 l of air may be exhaled and 4 l stay in the lungs. The air which is actually exhaled and then replaced is called the tidal air and its volume the ‘tidal volume’. By taking a very deep breath the tidal volume can be increased, but some of the 4 l will still remain: this volume is called the ‘residual volume’. This residual volume is composed of the air in the mouth and trachea as well as that which remains in the lungs. Yet another term which is used is the ‘vital capacity’, which is the maximum volume of air which can be expired following the deepest possible breath. The measured values of these parameters are a little arbitrary, of course, as they depend upon the effort made by the patient.
Respiratory System
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Arthur T. Johnson, Christopher G. Lausted, and Joseph D. Bronzino
Respiratory period (T) at rest 4 s Tidal volume (VT) at rest 4.0 × 10−4 m3 (400 cm3) Alveolar ventilation volume (VA) at rest 2.5 × 10−4 m3 (250 cm3) Minute volume during heavy exercise 1.7 × 10−3 m3/s (10,000 cm3/min) Respiratory period during heavy exercise 1.2 s Tidal volume during heavy exercise 2.0 × 10−3 m3 (2000 cm3) Alveolar ventilation volume during exercise 1.8 × 10−3 m3 (1820 cm3)
Reflection efficiencies of AnaConDa-S and AnaConDa-100 for isoflurane under dry laboratory and simulated clinical conditions: a bench study using a test lung
Published in Expert Review of Medical Devices, 2021
Azzeddine Kermad, Jacques Speltz, Philipp Daume, Thomas Volk, Andreas Meiser
The disadvantage of a lower reflection efficiency of ACD-50 must be weighed against its smaller carbon dioxide retention. Due to its smaller size, volumetric dead space of ACD-50 is smaller by 50 mL, and it also reflects less carbon dioxide leading to 15 ml reduced reflective dead space compared to ACD-100 [28–31]. In a clinical study, 10 spontaneously breathing patients reduced their tidal volume by 66 ml on average when switched from ACD-100 to ACD-50 with unchanged ventilator settings, opioid, and isoflurane infusion rates [32]. This is beneficial: First, a reduced tidal volume is crucial for lung protective ventilation. Second, a reduction in tidal volume decreases V-exh and thus increases reflection efficiency according to our findings (Figure 4). Third, a reduced minute ventilation decreases losses of isoflurane through the reflector even at the same reflection efficiency. In fact, in the before-mentioned clinical study [32], end-tidal isoflurane concentrations only decreased in two patients with V-exh higher than 5 mL. ACD-50 has also been used in the operating room and showed reduced anesthetic consumption compared to conventional circle systems operated with low- and even minimal fresh gas flow [33].
Modeling pressure relationships of inspired air into the human lung bifurcations through simulations
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2018
Parya Aghasafari, Israr B.M. Ibrahim, Ramana Pidaparti
When solving the Navier-Stokes equation and continuity equation, appropriate boundary conditions need to be applied. For the present study, inlet velocity boundary conditions are defined and written as UDF in C++ programming language. The C++ codes are written based on general breathing patterns for NB and MV. For NB, the inlet boundary condition in the trachea inlet (G0) was considered as a modified sinusoidal waveform profile and waveforms for MV were characterized by active constant inhalation and passive exhalation. The inlet velocity profile was considered as a function of the cross section (S) and time (t) during breathing which are categorized in Table (2) for NB and MV. The curves for inlet boundary conditions are drawn in Fig(3). where flow rate = (tidal volume/inhalation time). Tidal volume is the lung volume that represents the normal volume of air displaced between inhalation and exhalation when extra effort is not applied. The tidal volume was considered as 700 × 10−6 m3 for NB and 420 × 10−6 m3 for MV which represent mean and low tidal volume, respectively. Mean tidal volume was considered for NB and as previous studies have shown that low tidal volume can prevent VALI[34], lower tidal volume was considered for MV.
Modeling the therapy system of noninvasive pressure support ventilation with the respiratory patient in COPD and ARDS
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Yueyang Yuan, Lixin Xie, Wei Liu, Zheng Dai
As well know the main purpose with using NPSV for respiratory patient is to support the respiratory patient breathing with an enough tidal volume (Vt), and to promote the patient breathing in sufficient flash air and thoroughly breathing out the carbon dioxide (CO2). The effective ventilation is often decided by the tidal volume. For normal breath, the tidal volume is usually ranged in a volume of 8–10 mL kg−1 (or 400–800 mL) (Poon et al. 2015). Here the unit of “mL kg−1” means milliliter per kilogram of body weight. So in this article, the flows and tidal volumes were output for researcher directly observing.