Archive: Feb 2020

A novel, noninvasive assay shows that distal airway oxygen tension is low in cystic fibrosis, but not in primary ciliary dyskinesia

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Oxygen tension affects the biology of aerobic and denitrifying organisms. Using a novel, fast‐response sensor, we developed a noninvasive procedure to measure pO2 in distal human airways. We hypothesized that distal pO2 would be low in cystic fibrosis (CF) airways.

Materials and Methods

We measured the fraction of expired oxygen (FEO2) in real time using a fast laser diode analyzer in healthy subjects and in patients with CF, asthma, and primary ciliary dyskinesia (PCD). Subjects slowly exhaled to residual volume (RV), where the nadir of FEO2 (NFO) was recorded. Values were compared to peripheral oxygen saturation (SaO2), expired CO2 at RV, FEV1, FEV1/FVC, and FEF25‐75. We also measured the effect of supplemental oxygen on FEO2.


Seventy‐four subjects completed the study. Seven additional subjects could not perform the maneuver. Mean (±SD) NFO values for controls (n = 29), CF patients (n = 23), asthma patients (n = 15), and PCD patients (n = 7) were 13.4 ± 1.1%, 12.4 ± 1.2%, 13.3 ± 1.1%, 14.4 ± 0.6%, respectively. NFO in CF was lower than in controls (P = 0.0162), and NFO in PCD was higher than in CF (P = 0.0007). Asthma results were heterogeneous. Oxygen caused a dose‐dependent increase in NFO (P < 0.0005; n = 3; r2 = 0.91). NFO values were positively associated with FEV1 (P = 0.0009), FEV1/FVC (P = 0.0019) and FEF25‐75 (P = 0.0155), but there was no association with SaO2.



Distal airway pO2 is lower in CF than in controls. This may reflect absorption of oxygen in partially plugged acinar units, and/or increased epithelial oxygen consumption. Distal airway pO2 can be precisely titrated to treat infections.

Authors: Lori Mendelsohn BA(1),(2);  Christiaan Wijers BS(1),(2); Ritika Gupta BS(1),(2); Marozkina MD(2); PhD Chun Li PhD(3); Benjamin Gaston MD(1),(2)
(1) Division of Pediatric Pulmonology, RainbowBabies and Children’s Hospital, Cleveland,Ohio
(2) Department of Pediatrics, Division ofPulmonology, Case Western ReserveUniversity, Cleveland, Ohio
(3) Department of Population and QuantitativeHealth Sciences, Case Western ReserveUniversity School of Medicine, Cleveland,Ohio

First published: 28 November 2018; Pediatric Pulmonology

A novel, noninvasive assay shows that distal airway oxygen tension is low in cystic fibrosis, but not in primary ciliary dyskinesia (pdf)

Mechanical ventilators in the hot zone: Effects of a CBRN filter on patient protection and battery life

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In a contaminated environment, respiratory protection for ventilator dependent patients can be achieved by attaching a chemical, biological, radiological, or nuclear (CBRN) filter to the air intake port of a portable ventilator. We evaluated the effect of the filter on battery performance of four portable ventilators in a laboratory setting.


Each ventilator was attached to a test lung. Ventilator settings were: assist control (AC) mode, respiratory rate 35 bpm, tidal volume 450 ml, positive end-expiratory pressure (PEEP) 10 cm H2O, inspiratory time 0.8 s, and FIO2 0.21. Ventilators were operated until the battery was fully discharged. We also evaluated the ventilators’ ability to deliver all the gas through the CBRN filter and analyzed the pressures required to breathe through the anti-asphyxiation valve of a failed device.



The range of battery life varied widely across different ventilator models (99.8–562.6 min). There was no significant difference in battery life (p < 0.01) when operating with or without the CBRN filter attached. Only the Impact 731 routed all inspired gases through the CBRN filter. The pressure required to breathe though the failed device was −4 cm H2O to −9 cm H2O.


Duration of operation from the internal battery was not altered by attachment of the CBRN filter. The use of a CBRN filter is necessary for protection of ventilator dependent patients when environmental contamination is present, although conditions exist where all gas does not pass through the filter with some ventilators under normal operating conditions.

ArticleinResuscitation 81(9):1148-51 · September 2010


Authors: Thomas C. Blakeman (a) , Peter Toth (c), Dario Rodriquez (b), Richard D. Branson (a)
(a) University of Cincinnati Department of Surgery, Division of Trauma/Critical Care, Cincinnati, OH, United States
(b) Center for Sustainment of Trauma and Readiness Skills (CSTARS), United States Air Force, Cincinnati, OH, United States
(c) Medical Student, University of Cincinnati, Cincinnati, OH, United States

Mechanical ventilators in the hot zone: Effects of a CBRN filter on patient protection and battery life (pdf)

Oxygen/CO2 Analyzer for Capnography

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Model O2Cap Oxygen/CO2 Analyzer for Capnography:

Monitoring of the concentration or partial pressure of oxygen and carbon dioxide (CO2) in respiratory gases requires fast response without overshoot. The Oxigraf Oxygen/CO2 Analyzers respond in less than a second. Electrochemical sensors may incorporate long averaging times, 20 or more seconds, for large, abrupt changes in oxygen concentration. Laser diode technology offers short response times to meet your capnographic requirements. The O2Cap family integrates an Oxigraf oxygen sensor with a NDIR CO2 sensor for dual gas measurements for research, medical and laboratory measurements.



The Oxigraf O2Cap may be the O2/CO2 Analyzer you need:

  • Long life sensor, laser diode based sensor has a 10-year lifetime, does not require periodic replacement.
  • Fast response time, unit will respond to abrupt changes in O2 level in seconds.
  • NO errors due to vibration and movement
  • NO errors due to temperature changes
  • NO errors due to changes in barometric pressure
  • Accurately displays O2 levels for measuring 5-100% oxygen concentrations and 0 to 10% CO2

Oxigraf works with clients across a wide range of industries to address their unique analyzing needs. Recently, for instance, we helped a client who was looking for a way to perform capnography tests with fast breath by breath measurement. The detailed case study is outlined below.

The Problem:

This client was looking for a way to measure and display the oxygen and CO2 concentrations in a gas sample drawn through the instrument. The company turned to Oxigraf for a reliable capnography solution.

The Solution:

The Oxigraf O2Cap is an analyzer that integrates a gas sampling system with sensors to measure and display the concentrations of oxygen and carbon dioxide in a sample as the percentage of a gas in the sample by volume. This method of expressing the concentration of a gas in a sample is also known as the percent volume fraction. In addition to the sampling and sensing systems in the O2Cap, the unit has a fluorescent display used for programming the unit and observing measurements, a keypad for programming the unit’s operation and calibration, and analog outputs that allow the unit to be connected to data recording units like the OxiSoft.

When measuring the concentrations of oxygen and carbon dioxide in a gas, a sample is pumped from the input port on the front panel of the O2Cap, through the sample cell, and out an exhaust port on the back panel of the unit. Gas samples are drawn into the unit through an external filter on the input port that protects the sensors from contamination and through Nafion tubing on the filter that removes moisture from the samples that would affect the measurements and the unit’s calibration. The oxygen concentration of the gas in the sample cell is measured using laser diode absorption technology. The laser diode in the oxygen sensor produces light at a wavelength (760 nanometers) that is absorbed by oxygen. The light passes through the gas pumped into the sample cell and onto the surface of a detector.

The output of the sensor is inversely proportional to the concentration of oxygen in the sample because the amount of light reaching the detector decreases as the concentration of oxygen in the sample increases. The O2Cap has a very fast response time that enables breath to breath analysis of gas concentrations because the unit analyzes the gas sample every 10 milliseconds, or 100 times per second. During each measurement interval, the analyzer is zeroed automatically by electronic tuning of the laser to a wavelength not absorbed by oxygen.

The Oxigraf laser diode oxygen analyzer has a very long life span — especially compared to other options on the market — and requires no periodic replacement or servicing.

The Oxigraf Model O2Cap (AL) oxygen analyzer is a diverting oxygen monitor.  Gas may be flowed under pressure with the sample pump off or on. The major components, pneumatic circuit, and flow path are shown in the block diagram above.

The Result:

The client’s problem was easily resolved with the use of our O2Cap analyzer model, which allowed for an accuracy of +/-0.2%. This client was very pleased with the system we provided and has since spread the word about our product line and capabilities to other customers in the medical industry.

The O2Cap gas analyzer is calibrated at the factory and is ready to take measurements. Just connect the source of the gas sample to the gas analyzer with the proper connections and press the RUN key.

The model O2Cap and O2CapB have luer type front panel gas sample input fitting for research applications. The model O2CapD have CPC O-Ring quick connect gas sample fittings for industrial applications.
All of the Model O2Cap, O2CapB and O2CapD include a sampling pump that will draw a sample from atmospheric pressure; with an external flow control valve, it will accommodate pressurized gas up to 1.3 psig (17 psia or 120 kPa).
An optional gas sampling valve allows the pump to draw a sample for a programmable number of seconds. This feature is useful for sampling from Modified Air Packaging (MAP).

Oxigraf O2Cap Oxygen/CO2 Features:

  • Internal Sampling Pump.
  • Relay contacts can be used to control external equipment.
  • Relay contacts are Form C (SPDT), 5 A 250 VAC rating.
  • Analog 4 to 20 mA, analog 0 to 1 VDC, and digital RS-232 outputs. Visual, audible, and remote alarms for Low O2, High O2, Low Flow and System Check.
  • Samples and displays oxygen from 5 to 100% without range switching.
  • Calibrates electronically using 10%O2/5% CO2 and 100% O2 cal gases.
  • Electronic flow meter and display included.
  • Front panel CPC-Quick connect fitting.
  • Fast Response (< 1 sec) for prompt analysis.
  • Pressure and temperature correction automatical
  • No false oxygen readings with Ar, H2O, CO2, CO, or hydrocarbons.
  • Rugged laser diode absorption spectroscopy oxygen analysis.
  • Measures at low flows of 50 to 250 ml/min, conserving product gas.

Learn More:

Oxigraf has over 20 years of experience producing laser gas sensors and instruments and is the leading manufacturer of laser absorption spectroscopy sensors for oxygen gas measurement and analysis. Oxigraf O2iM Oxygen Safety Monitors have been widely adapted in hundreds of facilities since 2004, replacing a wide range of less reliable electrochemical sensors. Oxigraf O2 and CO2 sensors have been widely adapted by OEM manufacturers of medical respiratory gas monitors in order to measure breath waveforms, end-tidal gas values, anaerobic thresholds, VO2 max, and non-invasive cardiac outputs. For more information on our sensors, or to speak with an expert about your specific monitoring needs, contact the team today.

Please download your Oxigraf Case Study: Oxygen/CO2 Analyzer for Capnography (pdf)

CPET – Cardiopulmonary Exercise Testing

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A cardiopulmonary exercise test (CPET) is an evaluation of the cardiopulmonary system.

Physical exercise requires the interaction of the physiologic mechanisms that enable the cardiovascular and respiratory systems to support the energy demands of the contracting muscles.  Both systems are consequently stressed during exercise. Their ability to respond adequately to this stress is a measure of their physiologic competence.

  • Studies are performed under the direction of the cardiology and pulmonary divisions
  • Emphasis of testing may be influenced by the requesting division
    • Cardiac patients have more detailed electrocardiogram (ECG)/hemodynamic monitoring during testing
    • Pulmonary patient studies may include bronchial provocation with exercise testing
  • Exercise modalities
    • Bicycle ergometer
    • Treadmill
    • Selection of modality and protocol are dependent upon the requesting physician, level of fitness and health, weight, age, and patient preference

Model O2CPX – Cardiopulmonary Exercise Analyzer

The Model O2CPX is a table top analyzer used to monitor performance parameters during exercise testing. Breath-by-breath O2, CO2 and flow rate is measured precisely and accurately with internal sensors. Heart rate and pulse oximetry interfaces are compatible with Polar and Nonin accessories. Ambient temperature, humidity and barometric pressure is acquired for precise measurement correction. Our reliable solid state oxygen sensor does not require routine maintenance or factory calibration. Our O2CPX hardware easily collaborates with customer software solutions via USB interface.


KONA Software Designed for The Model O2CPX

Next generation cardiopulmonary exercise testing screen, with interactive breath-by-breath validation:

  • Visual test results viewer with custom charts and tabular breath-by-breath view.
  • Automatic VO2 and anaerobic thresholds can be manually overridden.
  • Custom reports including charts and key metrics.
  • FVC spirometry comparison test and pre/post FVCcomparison test.
  • Spirometry reports can be generated independently.
  • Patient management section with demographic information.
  • Easy calibrate screen. Pneumotachs are easily calibrated by entering a quick code.
  • Automatic flow volume correction using built in, temperature, humidity and barometric pressure sensors.
  • Oxygen saturation and polar heart rate input.
  • Optional ECG stress-test integration.
  • Optional multi-node test site version with shared relational database engine and support for 25+ test and review stations

Ergotron System Cart

Ergotron Neo-flex computer cart with height adjustable monitor and work surface for standing and sitting situations.
Complete systems cart configuration with mounting for

  • Oxigraf Model O2CPX Cardio-Pulmonary Exercise Test Analyzer mounting
  • Single monitor (up to 42 inch) or dual monitor mounting for 22 inch displays
  • Keyboard and Mouse work surface
  • Integrated Intel NUC computer mounting
  • Integrated power and cable routing
  • Mounting for 500L calibration gas cylinder on rear

Please download your O2CPX analyzer brochure.

Please download your KONA Software brochure.

Please download your Ergotron Cart brochure.