The TurboAire Challenger is a cost effective substitute for drug induced bronchospasm. Since no drugs or chemicals are administered, the patient risk is lower. The patient needs to be monitored for only one-half hour following the conclusion of the exposure to cold air, not the 2 to 4 hours suggested for drug related brochial provocation methods.

The TurboAire Challenger is an excellent source of portable arctic air for pronchial provocation and Exercise Induced Asthma studies throughout the year. Perform bronchial challenge using cold air, without the wait or worry associated with obtaining methacoline. Schedule tests when convenient. The TurboAire Challenger supplies cold air any time, anywhere.

The TurboAire Challenger has been marketed since 1984 and is preferred by research and clinical personnel to provide cold air for bronchial challenge.

• Low temperature: -20 degrees C
• Lightweight: 17 ounces
• Instant cold dry air
• Ease of use with either exercise or isocapnic hyperventilation
• Operates on compressed air from tanks
• No electricity, chemicals, or liquids
• No maintenance
• Low cost, economical operation
• Adult and pediatric mouthpiece options

Background

The purpose of performing bronchial provocation studies of any kind is to document the presence or absence of a physiologic response to a specific stimulus. The most common form of testing is done using a chemical or drug stimulus (Histamine, Methacholine, Formaldehyde, etc) which the patient inhales. These techniques are good for industrial or allergic asthma evaluation.

Exercise induced asthma (EIA) is a specific response and has been attributed to loss of water vapor from the airway, coupled with a thermal (cold) stimulus. To evaluate this specific response, it is necessary to produce a specific stimulus to cold, dry air. Until now, cold air generators worked with either copper coils immersed in a bath of acetone and dry ice or alcohol and dry ice or a heat exchanger from a freon refrigeration system. The patient inspires air through the coil with temperatures in the -5 to -10 degree C range. Both these methods require bulky systems which are difficult to get near the patient and the chemical based coolers have the added potential hazard of the patient inhaling the cooling solution vapors.

A Better Way

The turboaire challenger is the first system to offer absolute cold and dry inspired gas in a in a small package which can be easily brought to the patient on a treadmill or ergometer. It has no moving parts and uses no chemicals. The total flow available to the patient is approximately 240 liters/minute of air at -10 to -15 degrees C.

The temperature is controlled by pressure regulator (80 to 110 psig) and the inlet gas temperature is reproducible to within 0.6 degree C. Due to the relatively high pressures and total flow required, hospital piped air systems are insufficient to operate the Challenger at sub-zero temperatures. Operation using wall air is possible with some reduction in temperature differential and total flow. The cost to hospitals for an "H" or "K" cylinder of compressed air ranges from $7.00 to $10.00, maintaining a low cost per test. Testing time per cylinder ranges between sixteen and twentyfour minutes depending on tank and temperature selection. The standard system uses 375 liters of air per minute. 35% of this is used to cool, resulting in 244 liters/min being deliverd to the patient.

Most protocols call for breathing the cold air for 6 to 8 minutes at 60 to 80% predicted maximum work. There are no valves in the mouthpiece block and it is made of natural acetyl. There is a 10-32 threaded port at the top of the block for placement of a temperature probe or a hose barb for a CO2 line.

Standard Turboaire Challenger includes the cold air generator, breathing block and pediatric and adult mouthpiece adapters in a permanent carrying case. For standard cold air provocation tests you will also need a high pressure hose (No. 2009-1) and high flow regulator (No. 2009-4). A standard ventilator supply hose can be used as a high pressure hose.

Isocapnic Hyperventilation

The Turboaire Challenger can be easily configured for use with isocapnic hyperventilation protocols. The Challenger is connected to a 2-way valve. The outlet of the valve is attached to the Target Ventilation Meter.

CO2 can be titrated into the system at the breathing block. The 2-way valves have ports for placement of a temperature probe and a CO2 analyzer sample line. Reference 1 used titrated flows of 1-2 liters per minute of 100% CO2 and a target flow rate of 15 to 25 times the patient's FEV1. (Better buy pre-mixed CO2 in Air) These flowrates were in children and higher flows may be required in adults. It has been recommended that end-tidal CO2 be monitored to prevent accidental hypercapnia. VacuMed's model 17515 CO2 analyzer automatically displays end-tidal CO2. (Use #2009-3 High Flow Regulator for the CO2/Air mixture)

Principle of Operation

The Turboaire Challenger produces cold air with a generator that works on a pure physical principle. There are no moving parts in the generator and it is the physical geometry of the generator which provides this unique characteristic.

Figure 3 is a schematic of the internal geometry of the Challenger's generator. High pressure enters the side inlet of the generator chamber. As it enters the nozzles, it loses part of its pressure as it expands and gains sonic or near sonic velocity. The nozzles are aimed so that the air is injected tangentially at the circumference of the generation chamber. All of the air leaving the chamber goes into the hot tube. It makes this choice because the opening to the hot tube is always larger that the opening to the cold end. Centrifugal force keeps the air in a zone near the inside surface of the hot tube as it moves toward the valve at the end.

Thirty-five percent of the air traveling down the hot end exits the hot tube valve. The remaining air is forced back to the center of the hot tube where, still spinning, it moves back toward the cold outlet. I goes all the way through the hot tube, through the center of the generator chamber and into the cold outlet.

The original stream of air in the hot tube did not occupy the center of the tube because of centrifugal force. Therefore it defines an ideal path of the inner stream to follow. The outer ring of air is moving towards the hot end and the inner ring is moving toward the cold end. Both streams are rotating in the same direction and at the same angular velocity. Kinetic energy is proportional to the square of the linear velocity. Particles within the inner ring travel with a lower linear velocity as compared to those in the outer ring so that the particles leaving the cold end have 1/16th of their entering kinetic energy. This energy leaves the inner core as heat and is transferred to the outer core. The absolute temperature drop is proportional the driving pressure. Lower outlet temperatures will be obtained with lower inlet temperatures and/or higher driving pressure.

A booklet detailing technical Issues and Protocol is available for download. To become an expert, Click here to download a PDF file.

The following components (listed below) are included in number 2009-10 "complete system":
2009, 2009-1, 2009-4, 2012, 2012-1, TAC2700.
For pediatric use, order separately (or substitute for TAC2700) the TAC2600 valve.
No. 2009-4 high flow regulator fits only to a compressed air tank, order separately (or substitute for 2009-4) no. 2009-3 for CO2 mix regulator.
Large tanks (H-size) of compressed air should be purchased locally.

Last Updated: 28 Feb 2022

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