Evaluation of thoracic mechanics in the ventilated patient part 1: Primary measurements

The cause of the initial hyperventilation, which occurs on exposure to O2 at high pressure (o.h.p.), has been investigated by measuring tidal volume (VT), frequency of breathing (f) and hence ventilation (VE) in thirty-six barbiturate-anaesthetized rats, with or without their glossopharyngeal (IX) nerves sectioned, during 30-60 min of exposure to o.h.p. at 4, 6 or 8 atm absolute. In intact rats the rates of rise of VT, f and VE with time during exposure to o.h.p. were smallest at 4 and greatest at 8 atm absolute. In IX-sectioned rats the rates of rise of VT at 4, 6 and 8 atm absolute and of f at 4 atm absolute were similar to those of intact rats. At 6 atm absolute and even more so at 8 atm absolute, however, f decreased. Hence the slope of VE in IX-sectioned compared with intact rats was similar at 4 atm absolute but smaller at 6 and 8 atm absolute. In fact at 8 atm absolute VE remained constant in IX-sectioned rats. Since the slope of VE versus time in intact rats was steeper the greater the pressure and since the removal of carotid bodies in IX-sectioned rats reduced the VE slope at 6 and 8 atm absolute, the stimulus to the hyperventilation induced by o.h.p. cannot be an accumulation of CO2 in the brain resulting from the lack of O2 desaturation of haemoglobin. This theory would predict that VE should be identical at all pressures above 3.5 atm absolute. The findings in the IX-sectioned rats indicate a major contribution of the carotid bodies to the f increase in o.h.p. They may be stimulated by a histotoxic hypoxia induced by early O2 poisoning. Since the VT increase on exposure to o.h.p. was both large and fairly similar in intact and IX-sectioned rats, it is suggested that a large part of the VT increase was caused by stimulation of the central chemoreceptors by lactic acidosis induced by an o.h.p.-induced histotoxic hypoxia of the brain.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1986.sp015946

Ventilation in intact and glossopharyngeal nerve sectioned anaesthetized rats exposed to oxygen at high pressure.

Some aspects of the linearity and the frequency response of flow measurement with Fleisch type pneumotachometers are considered. The transition from a uniform velocity distribution at the entrance of the capillary tubes of the transducer to a fully developed flow profile is discussed as one of the phenomena influencing the linearity of the set-up. Besides, an expression is derived for the frequency response of the Fleisch pneumotachometer. The frequency responses as derived from measurements show good agreement with theory. In the range of the lower frequencies the frequency response of the flow measuring set-up is proved to be largely determined by the frequency response of the pressure transducer with the connecting tubes. A simple way is indicated to measure the latter. This, in combination with the calculated frequency response of the flow transducer, makes it fairly casy to determine the frequency response characteristics of a flow measuring set-up containing a Fleisch type pneumotachometer.

Linearity and frequency response of Fleisch type pneumotachometers.

Giannella-Neto, A., C. Bellido, R. B. Barbosa, and M. F. Vidal Melo. Design and calibration of unicapillary pneumotachographs. J. Appl. Physiol.84(1): 335–343, 1998.—This study presents a method fo...

Design and calibration of unicapillary pneumotachographs

Respiratory effects of cold-gas breathing in humans under hyperbaric environment.

Measurement of ventilatory flow during pulmonary function maneuvers and in severe exercise by the pneumotachograph flow transducer in dense atmospheres is handicapped by the inverse relationship between the linear range ofsuch transducers and gas density. This limitation in the usefulness of the pneumotachograph can be overcome by mounting such flow transducers in parallel and taking into account the reduction in peak ventilatory flow transducers in parallel and taking into account the reduction in peak ventilatory flow which occurs with increasing density. The design of such assemblies, their static performance characteristics, and a drift subtractor, constructedto stabilize the output of the pneumotachograph pressure transducer, are described.

Pneumotachograph for flow and volume measurement in normal and dense atmospheres

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

R. Gelfand

Author Tools

Chat about Author

Papers

Pneumotachograph for flow and volume measurement in normal and dense atmospheres