Resistance pulmonary, measurement

Dodoo AN, Bansal SS, Barlow DJ, Bennet F, Hider RC, Lansley AB, Lawrence MJ, Marriott C (2000) Use of alveolar cell monolayers of varying electrical resistance to measure pulmonary peptide transport. J Pharm Sci 89(2) 223-231... 

Cardiac output can be measured using dye- or thermal-dilution techniques or by placement of an electromagnetic flow probe around the pulmonary artery. Insertion of a pressure transducer or fluid-filled catheter into the pulmonary artery and pulmonary vein allows for the calculation of pulmonary vascular resistance. The measurement of flow through the proximal aorta may also be useful but does not include coronary blood flow and as such is not equivalent to... 

Monitoring the patient in shock requires vigilance on the part of the nurse The patient s heart rate, blood pressure, and ECG are monitored continuously. The urinary output is measured often (usually hourly), and an accurate intake and output is taken. Monitoring of central venous pressure via a central venous catheter will provide an estimation of the patient s fluid status. Sometimes additional hemodynamic monitoring is necessary with a pulmonary artery catheter. The use of a pulmonary artery catheter allows the nurse to monitor a number of parameters, such as cardiac output and peripheral vascular resistance The nurse adjusts therapy according to the primary health care provider s instructions. 

Pulmonary artery catheter An invasive device used to measure hemodynamic parameters directly, including cardiac output and pulmonary artery occlusion pressure calculated parameters include stroke volume and systemic vascular resistance. 

Total Respiratory Resistance (/ i) - With appropriate attention to technical problems, resistance can be measured at various pressure perturbation frequencies of 3, 6, 9, and 12 Hz. Unfortunately, this measurement is affected by changes in upper-airway configuration, which may complicate the detection of changes in pulmonary airways per se. 

Several authors measured attainable pressure drops as a function of the external resistance for different groups of volunteers. Healthy male subjects (during maximal inspiration) are able to create a pressure drop (on average) of 6.7 kPa through an airflow resistance of 0.038 kPa° min 1, (which is in the range of that of marketed DPIs, see Table 3.7), whereas females are able to create a pressure drop of 3.8 kPa under the same resistance [22]. Differences between different groups of patients depend on the degree to which pulmonary func-... 

Mitsuhata et al. (1994) induced systemic anaphylaxis in dogs sensitized to Ascaris suum by intravenous injection of the antigen and measured pulmonary resistance and dynamic pulmonary compliance. 

PURPOSE AND RATIONALE Measurement of cardiac function and morphology is a key part of the preclinical evaluation of experimental medicinal compounds. Blood pressure, heart rate, and electrocardiogram evaluation are part of the core portfolio of safety pharmacology studies carried out in conscious telemetry dogs. If results from the core battery of tests raise concern then supplemental studies are conducted to measure endpoints such as left ventricular pressure, pulmonary arterial pressure, heart rate variability, baroreflex, cardiac output, ventricular contractility and vascular resistance. However, many... 

It is often possible to address function more specifically in in vitro assays, where functional parameters are usually very sensitive readouts of adverse effects. For example trans-epithelial electrical resistance (TEER) is a very sensitive marker of epithelial disturbances. TEER measures the barrier function of the entire mono-layer and is utilized to study functional disturbances of many epithelial/endothelial cell types including blood-brain barrier, pulmonary, renal, and gastrointestinal cells. Its sensitivity lies in the fact that only a small proportion of cell death has a very large impact on barrier function. Additionally, cell stress can interfere with the arrangement and population of tight junction proteins [16] thus, TEER can in certain conditions measure functional disturbances in the absence of cell death [13]. Also since TEER can be measured noninvasively, it is nondestructive and can be used to monitor the effects of treatment over days and weeks [13, 17]. For excitable cells, electrical activity has also been proven to be an extremely sensitive parameter of adverse drug reactions and microelectrode arrays have been employed successfully to monitor neurotoxicity in vitro [18]. Also, for contractile cells, such as cardiomyocytes, the use of impedance measurements to measure the effects of compounds on spontaneous contraction has been demonstrated to be a very sensitive functional monitoring parameter in vitro [19, 20], Admittedly, none of the aforementioned techniques are true biomarkers per se however, such measurements illustrate the fact that in vitro techniques allow certain possibilities that are not practically tenable in the whole body. 

Invasive hemodynamic monitoring usually is performed with a flow-directed pulmonary artery (PA) or Swan-Ganz catheter placed percutaneously through a central vein and advanced through the right side of the heart and into the PA. Inflation of a balloon proximal to the end port allows the catheter to wedge, yielding the PAOP, which estimates the pulmonary venous (left atrial) pressure and, in the absence of intracardiac shunt or mitral valve or pulmonary disease, left ventricular diastolic pressure. Additionally, cardiac output may be measured and systemic vascular resistance (SVR) calculated. Normal values for hemodynamic parameters are listed in Table 14—12. 

RV function. Another technique to assess RV function is the measurements of isovolumic relaxation time (IVRT). Prolonged right ventricular IVRT in IPAH patients was found to be the strongest predictor of clinical status and survival (35). Another novel method of predicting outcomes in patients with IPAH is Doppler measurement of pulmonary vascular capacitance, which is calculated by utilization of the relationship between stroke volume and pulmonary pulse pressure. In multivariate analysis, echo-calculated pulmonary vascular capacitance correlated more strongly with outcomes than invasively measured mPAP, RA pressure, and pulmonary vascular resistance (PVR) (36). 

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