Respiratory Care Medical Gases and Equipment Flashcards

100 question and answer flashcards covering medical gas physics, safety systems, cylinders, concentrators, and flow meters based on lecture transcript notes.

How is the medical oxygen coming out of hospital wall units produced from bulk supplies?

Liquid oxygen is allowed to boil, causing a phase change from liquid to gas.

Why is medical oxygen cold and dry when delivered from wall outlets?

Oxygen's boiling point is extremely low, and raw piped oxygen contains $0\%$ relative humidity.

What severe injury can direct skin contact with liquid oxygen cause?

It can cause significant freezer burn or completely freeze fingers off.

Is pure oxygen gas itself flammable?

No, oxygen is not flammable on its own, but it supports and accelerates combustion.

What medical classification applies to oxygen when administered to patients?

It is classified as a medicinal gas (drug) requiring a physician's or provider's order.

What is the primary purpose of nontherapeutic gases in healthcare?

They are used to calibrate machinery and occasionally perform diagnostic testing.

What does STPD stand for in medical gas measurement?

Standard Temperature and Pressure Dry.

Under what clinical conditions are medical gases delivered raw at bedside?

Ambient Temperature and Pressure Dry (ATPD).

What is the relative humidity percentage of piped medical gases coming directly from wall units?

$0\%$ relative humidity.

Why do oxygen wall outlet stickers instruct 'use no oil'?

Because oil or organic lubricants can spontaneously combust in the presence of pure oxygen.

How does heating affect the viscosity of a gas compared to a liquid?

Heating increases the viscosity of a gas, whereas it decreases the viscosity of a liquid.

Which two medical gases are clinically evaluated for their density properties?

Helium and oxygen.

What is Heliox and what conditions is it used to treat?

A mixture of helium and oxygen used to treat asthma and upper airway obstructions.

How is specific gravity defined in respiratory care?

The density of a gas compared relative to the density of pure oxygen.

What flow pattern describes gas traversing the airways before reaching the alveoli?

Bulk flow under jet stream conditions.

What form of molecular movement occurs when gas reaches the alveoli?

Molecular diffusion, characterized by random particle movement.

How does boiling differ from surface evaporation?

Boiling requires the entire liquid volume to reach its boiling point temperature.

What is the term for cold, visible particulate liquid droplets suspended in delivered gas?

Aerosol.

What happens if the vacuum insulation inside a liquid oxygen system is breached?

The liquid oxygen boils violently almost instantly.

What components allow siphoned liquid oxygen to convert into gas in bulk supply systems?

Evaporator coils.

What is the triple point temperature of water in degrees Celsius?

$0.01^\circ\text{C}$.

What is gas solubility?

A gas's ability to dissipate inside a liquid solution.

What are the two most common sizes of compressed gas cylinders used in healthcare?

The E cylinder and the H/K cylinder.

What is the physical height of a standard E cylinder?

Approximately knee high.

What active ingredients are present in Neuro gum?

$60\,\text{mg}$ of caffeine along with L-theanine.

Which agency regulates compressed gas cylinder transportation and testing standards?

The Department of Transportation (DOT).

Which standardizing committee specifically establishes guidelines for medical oxygen equipment?

The Z79 committee.

What gas is commonly utilized in healthcare facilities for medical equipment sterilization?

Ethylene oxide (ETO).

What treatment intervention is proven to extend life expectancy in chronic hypoxic patients?

Long-term oxygen therapy (LTOT).

What is the standard full pressure rating for a compressed medical gas cylinder?

Approximately $2,015\,\text{PSI}$ to $2,200\,\text{PSIG}$.

What is the fraction of inspired oxygen ($FiO_2$) in standard room air and medical air?

$21\%$ (or $0.21$).

What are the primary component gases of purified medical air?

$21\%$ oxygen ($O_2$) and $79\%$ nitrogen ($N_2$).

Which gas is denser: pure oxygen or room air?

Pure oxygen is more dense than room air.

What is the universal color code for oxygen cylinders in the United States?

Green.

What is the universal color code for medical air cylinders in the United States?

Yellow.

What does USP stand for on medical gas cylinder labels?

United States Pharmacopeia.

What primary industrial process produces commercial pure oxygen gas from atmospheric air?

Fractional distillation of liquefied air.

What chemical formula represents the diatomic oxygen molecule?

$O_2$.

What two clinical factors dictate the risk of developing oxygen toxicity?

Oxygen concentration ($FiO_2$) and duration (contact time) of exposure.

Which exposure carries a higher risk of oxygen toxicity: $40\%$ oxygen for $24\,\text{hours}$ or $100\%$ oxygen for $1\,\text{hour}$?

$40\%$ oxygen for $24\,\text{hours}$, due to the prolonged duration of contact.

In the obstructive airway disease mnemonic, what does 'A' stand for?

Asthma.

In the obstructive airway disease mnemonic, what does 'B' stand for?

Bronchiectasis.

In the obstructive airway disease mnemonic, what does 'C' stand for?

Cystic fibrosis.

In the obstructive airway disease mnemonic, what does 'F' stand for?

Foreign body airway obstruction.

What clinical symptom indicates a patient requires increased gas flow rather than higher $FiO_2$?

Air hunger or dyspnea despite adequate oxygen saturation ($99\%$).

How many liters of gaseous oxygen are produced by expansion of $1\,\text{L}$ of liquid oxygen?

$860\,\text{L}$ of gaseous oxygen.

What internal temperature must be maintained inside a liquid oxygen vessel?

Less than $-183^\circ\text{C}$.

What is the main physical hazard of a compressed cylinder versus a liquid oxygen container?

Compressed cylinders pose a high-pressure explosion hazard, whereas liquid systems pose a cryogenic burn hazard.

What home device uses molecular sieves to concentrate oxygen from room air?

An oxygen concentrator.

What three standard Heliox mixture concentrations are available?

$80/20$, $70/30$, and $60/40$.

What is unique about the $80/20$ Heliox concentration regarding its oxygen proportion?

It delivers $20\%$ oxygen, which is lower than room air $FiO_2$ ($21\%$).

What is the primary pharmacological action of inhaled nitric oxide (INO)?

It acts as a selective pulmonary vasodilator.

What clinical condition is specifically treated with inhaled nitric oxide?

Pulmonary hypertension.

Why does inhaled nitric oxide avoid causing systemic hypotension?

It is rapidly bound and inactivated by hemoglobin in pulmonary capillaries.

What toxic waste gas can form in the ventilator circuit during inhaled nitric oxide delivery?

Nitrogen dioxide ($NO_2$).

What blood disorder can result from elevated nitrogen dioxide exposure?

Methemoglobinemia.

What gas mixture is known as Carbogen and what medical issue does it treat?

A mixture of $O_2$ and $CO_2$ used to treat singultis (severe hiccups).

What is the formal medical term for hiccups?

Singultis.

In what pulmonary function test are tiny concentrations of carbon monoxide (CO) administered?

DLCO (Diffusion Capacity of the Lung for Carbon Monoxide).

What condition develops if excessive carbon monoxide gas is absorbed into blood hemoglobin?

Carboxyhemoglobinemia.

What historical anesthetic gas was discontinued due to high explosive flammability?

Cyclopropane.

How does Heliox therapy assist patients with severe upper airway obstruction?

Its low density reduces resistance to flow, carrying oxygen past the obstruction.

What is cor pulmonale?

Right-sided heart failure secondary to chronic pulmonary hypertension or lung disease.

How does inhaled nitric oxide help manage cor pulmonale?

It dilates pulmonary vessels, reducing right ventricular afterload.

What clinical risk occurs if a severe chronic COPD patient receives excessive $FiO_2$?

Blunting of the hypoxic drive, leading to hypoventilation and CO2 narcosis.

What pressure condition must exist for one compressed cylinder to transfill into another?

The donor cylinder pressure must exceed the pressure of the receiving cylinder.

When does gas flow stop during cylinder transfilling?

When both cylinders reach equal pressure (equilibrium).

What standard working pressure is maintained in hospital medical gas pipeline systems?

$50\,\text{PSIG}$.

What pipeline components permit selective shutoff of medical gases to specific clinical hospital zones?

Zone valves.

What is the universal color code for helium cylinders?

Brown.

What international color code is sometimes used for oxygen outside the United States?

White.

What tank mark indicates a cylinder is constructed from heat-treated steel?

$3\text{AA}$.

What tank mark indicates a cylinder is constructed from aluminum?

$3\text{AL}$.

What does a star ($*$) stamp on a gas cylinder signify?

The cylinder qualifies for a $10\text{-year}$ hydrostatic retest interval.

What does a plus ($+$) sign stamp on a cylinder signify?

The cylinder is approved for a $10\%$ overfill above working pressure (up to $2,200\,\text{PSI}$).

What is the cylinder factor for an H/K compressed gas cylinder?

$3.14\,\text{L/PSI}$.

What is the cylinder factor for an E compressed gas cylinder?

$0.283\,\text{L/PSI}$.

At what gauge pressure is a medical gas cylinder considered near empty and ready for replacement?

Below $500\,\text{PSI}$.

What equation calculates cylinder duration of flow in minutes?

$\text{Duration (min)} = \frac{\text{Pressure (PSI)} \times \text{Tank Factor}}{\text{Flow Rate (L/min)}}$.

How long will a full E cylinder ($2,200\,\text{PSI}$) last running at $3\,\text{L/min}$?

Approximately $207\,\text{minutes}$ (or $3.4\,\text{hours}$).

How many total liters of gas are contained in a full E cylinder at $2,200\,\text{PSI}$?

Approximately $660\,\text{L}$.

Which pressure relief device melts when exposed to high fire temperatures?

Fusible plug.

Which pressure relief device ruptures when internal cylinder pressure exceeds safety limits?

Frangible disc.

Which pressure relief device opens under excess pressure and reseals when normal pressure returns?

Spring-loaded valve.

What safety connection system is utilized for large cylinders such as H/K tanks?

ASSS (American Standard Safety System).

What safety connection system is utilized for small cylinders such as E tanks?

PISS (Pin Index Safety System).

What low-pressure safety system ($<200\,\text{PSIG}$) is used for station outlets and flow meters?

DISS (Diameter Index Safety System).

What pin position hole combination designates oxygen in the Pin Index Safety System?

Positions $2$ and $5$.

What pin position hole combination designates medical air in the Pin Index Safety System?

Positions $1$ and $5$.

What seal component must be positioned between an E cylinder valve stem and the yoke regulator?

A washer (gasket).

What manual tool opens and closes an E cylinder valve stem?

An oxygen key (cylinder wrench).

In which direction do you turn a cylinder valve stem to open gas flow?

Counterclockwise (lefty loosey).

What hazard exists when transporting a patient on a pressurized cylinder with a closed main valve stem?

The flow meter bleeds off residual line pressure, causing gas flow to suddenly stop.

What is the proper technical name for a Christmas tree oxygen adapter?

Swiveling threaded nut and nipple adapter.

What defines a pressure-compensated Thorpe tube flow meter?

It reads accurately in the presence of downstream outlet resistance or obstruction.

How do you test if a Thorpe tube flow meter is pressure-compensated when connecting to a wall outlet?

The float ball jumps up and falls back down immediately upon insertion.

Where on the float ball is flow rate measured on a standard round-ball Thorpe tube?

At the center of the ball.

Where is flow setting measured on a cylinder or pellet-style float?

At the top flat surface of the float.

What happens to delivered $FiO_2$ purity from an oxygen concentrator as flow rate is turned up?

The oxygen purity ($FiO_2$) decreases.

What is the major clinical inaccuracy of a Bourdon gauge flow meter when downstream obstruction occurs?

It indicates a falsely high flow rate relative to the actual lower flow delivered to the patient.