inhalation sedation equipment
Cylinders
3/8-inch-thick steel although some cylinders of N2O have been made of aluminum Tested every 5 years to ensure integrity with internal hydrostatic pressure, the pressure depending on the size of the cylinder
regulators delivery pressure
45 to 55 psig Located between cylinders of gas and flowmeters on yoke on portable units Located usually on cylinder in central systems
major advantage demand flow unit
economy obtained from the decreased volume of compressed gases used
scavenging system
with N2O sedation equipment is desirable because it removes any potentially toxic waste gas from the environment
minimum oxygen liter flow
- inhalation sedation units are designed so that once turned on the unit delivers a preset minimum liter flow of O2 through the flowmeter. In most units this minimum flow is 2.5 or 3 L/min of O2. The flow of N2O cannot start until a flow of O2 has been established.
Nitronox
A type of demand-flow used in hospital and ambulatory settings Unique in that percentage is not adjustable, is fixed at 50/50, O2 and N2O and is extremely accurate
ratio of use
About 2.5 cylinders of O2 are used for every N2O cylinder
flowmeter adjustment
Adjustment of gas flow is accomplished by a fine-needle valve for each flowmeter, the knobs are both touch-coded and color-coded (in U.S. O2 control knob is green and fluted, N2O knob is blue and not fluted) Also O2 flowmeter is positioned on the right side of the flowmeters
bag tee flowmeter
Anesthetic gases leave the tops of their respective flowmeters and are combined in the mixing chamber, found in the head of the sedation unit From this point, a combination of gases flows through the machine and now exit the sedation unit through the outflow tube, known as a bag-tee and carried to the patient
yokes (portable system only)
Assembly holds cylinder of compressed gas tightly in contact with portable sedation unit Circuit of gases - from cylinder through yoke and into reducing valve - "the high-pressure system"; from reducing valve to patient - "the low-pressure system" From reducing valve, the gas enters low-pressure tubing, color-coded for specific gases, that conducts gas to attachments at the rear of sedation unit
Reservoir bag
Bladder-type bags, with the 3-L used most commonly in dentistry Attaches to base of bag-tee, usually immediately below emergency air inlet valve A portion of the gases may be diverted into the reservoir bag
Diameter Index Safety System (DISS)
Designed to ensure correct gas enters the correct part of the sedation machine Makes it physically impossible to inadvertently attach wrong tubing to wrong inlet of machine
safety features of cylinders
Color coded: N2O blue; O2 green Pin index safety system makes it physically impossible tor a N2O cylinder to be inadvertently attached to O2 portion
types of inhalation units
Continuous flow machine Intermittent-or demand-flow unit
cylinders handle
Cylinders are designed to handle 1.66 times the usual pressure Marked with a metal stamp indicating the date the cylinder was commissioned, dates of testing, the pressure for which the cylinder was designed, insignia of testing facility, and identification of manufacturer
demand flow dial
Dial provides a direct indication of the percentage of O2 delivered in the mixture; the remainder of the gas is N2O Units only show what was set, not what was actually delivered
Demand Flow Units
Does not deliver gas continuously to the patient Varies rate and flow of delivered gas according to patient's respiratory demands and requirements
demand flow disadvantage
Flow of anesthetic gases per minute is not visible or registered anywhere on the machine (cannot be visibly monitiored) Instead there is a dial on which percentages of gases are recorded and another on which the pressure at which they are delivered is visible
regulator function
Function to reduce high-pressure gas from cylinder to a pressure safe for patient and sedation unit maintain constant gas pressure to flowmeters and to patient regardless of gas pressure contained within the cylinder, important to minimize potential for damage
flowmeter instruction
Gas enters a taper tube, grows wider from bottom to top A float is inside the flowmeter for measuring volume When flow of gas begins, the gas forces the float up into the tube Calibrations on the tube indicate flow of gas in liters per minute (L/min)
Compressed gas cylinders
Gases dispensed at a pressure greater than 25 lb per square / 25 psig - pounds per square inch gauge pressure at 25 degree C or 70 degrees F are considered compressed gases according to hazardous materials regulations of the U. S. Department of Transportation (DOT) Because of potential for serious injury from improper handing of these cylinders, DOT has regulations
Regulator (temperature)
It is in the reducing valve that recompression of gases produces the tremendous increase in temperature to 815 - 1093 degrees C (1500 - 2000 degrees F). temp increase can ignite oil, grease, or Teflon if found in this area, leading to explosion and fire.
ratings
It is recommended that a sedation unit should have received an acceptable rating from the ADAs Council on Scientific Affairs This listing is published in the Journal of the American Dental Association, the Dentist's Desk Reference, and on the ADA website (www.ada.org)
manifolds (central system only)
Joins multiple compressed-gas cylinders Also found on manifold is a safety pressure relief valve and an alarm that activates when pressure is too high or low
Emergency air intake valve
Located on bag-tee above reservoir bag In the event the sedation unit ceases to function and gas flow from the machine is terminated, it provides a supply of atmospheric air all equipment latex free
nitrous oxide cylinder and contents
N2O is present in both liquid and gaseous states presence of liquid N2O in the cylinder, the gas pressure gauge will record "full" as long as any liquid remains in the cylinder
color code of cylinders
N2O: light blue O2: green
oxygen cylinder contents
O2 cylinder contains only gas Pressure gauge on machine yoke reflects actual contents of cylinder
flowmeters
Permits administrator to deliver a precise volume of either gas to patient Flowmeters measure actual quantity of gas in motion not cylinder pressure; if flow is interrupted, flowmeter will read zero
Central Storage System with mobile heads
Permits the use of larger compressed-gas cylinders with mobile heads but the inhalation sedation unit sits on a portable stand without a yoke apparatus It may be moved from treatment room to treatment room Quick connect tubing attaches the unit to O2 and N2O outlets on the wall
continuous flow subgroups
Portable systems Central storage system Central storage system with mobile heads
portable systems
Rolling stand compressed-gas cylinders attach at the yoke assembly Used when frequency of use is low or expense of central storage system is prohibitive Primary drawback: because they require use of smaller cylinders, they require replacement more frequently and cause a higher cost
nitrous oxide cylinder pressure full tank
The pressure in a full tank of N2O is 650 - 900 psi
pressure in full tank of o2 is
The pressure in a full tank of O2 is 1800 - 2100 psi
nitrous cylinder half tank pressure
The pressure in a half-full tank of N2O is 650 - 900 psi This is because the contents of a tank of N2O contains both liquid and gas
the pressure in a half full tank of o2 is
The pressure in a half-full tank of O2 is 900 - 1100 psi This is because the contents of a tank of O2 contains only gas
Central Storage System
The supply of N2O and O2 is located a distance from the area where the gases are delivered Large cylinders are used Multiple treatment areas may be connected by copper piping If inhalation sedation is used regularly, there is a savings using the larger gas cylinders
considerations for handling compressed gas cylinders
Use no grease, oil, or lubricant of any type to lubricate cylinder valves, gauges, regulators, or other fittings that may come into contact with gases - extremely dangerous 2. Store full cylinders in vertical position 3. Store cylinders in an area where temperatures do not fluctuate - avoid heat in particular handle with care, open valve slow counterclockwise , valves must fully be open to prevent gas leak. close cylinders tight to prevent contamination cylinders should be cracked before attached to machine.
Color Coding Safety System
all parts of the sedation unit that carry or operate O2 are colored green in the U.S., whereas tubes, knobs, and other parts handling N2O are colored light blue
automatic manifolds
automatically activates a new full reserve cylinder of gas when cylinder in use empties
oxygen fail safe
automatically terminates the flow of N2O whenever the delivery pressure of O2 falls below a predetermined level, approximately 50 psig. When the delivery pressure of O2 through the reducing valve can no longer be maintained at 50 psig, the O2 fail-safe mechanism is activated and the flow of N2O gas is terminated.
demand flow falls below standard
because it prevents the important practice of titration from occurring
conducting tubes
breathing tube, connects bag-tee to nasal hood Large diameter and corrugated, minimizes resistance to flow of gases and prevents kinking
continuous flow units
characterized by continuous flow of gases regardless of respiratory pattern of patient Gas continues to be delivered through the machine even as patient exhales These units use greater volume of gas over a given period of time Greater accuracy and safety compared to demand-flow
Size of cylinders
classified by letters "A" the smallest, "HH" the largest "E" cylinders are used for both N2O and O2 in portable units "G" cylinders for N2O and "H" for O2 use in central storage systems
Nasal Hood
device designed to fit comfortably and securely over the patient's nose Tubes deliver gases from sedation unit, 2 tubes deliver gases, two tubes carry away exhaled gases
emergency air inlet
located on top of the bag-tee outlet, the emergency air inlet is maintained in a closed position as long as O2 or N2O - O2 is being delivered. When the flow of gases ceases, the emergency air inlet valve opens, permitting the patient to continue to breathe, now atmospheric air.
gas cylinders
maintained in a storage area and gases are delivered to treatment area through copper pipes
nonautomatic manifolds
most common. When a cylinder is empty, it must be physically turned off and new one opened
digital electronic flow control devices
now available on N2O - O2 sedation devices
disadvantage of continuous flow
of the demand-flow unit are eliminated Eliminated is the inability to visualize flow of gases and inaccuracy of the mixer valve
central storage systems with mobile heads are recommended for?
offices in which economics of central storage warrant its instillation but frequency of use of inhalation sedation does not justify purchase of heads for all treatment areas
demand flow unit parts
one dial which changes the percentages of gases delivered
Oxygen flush button
permits rapid delivery of high flows of O2 to the patient. N2O delivery is automatically stopped when the oxygen flush button is pressed. The button is ideally located on the front of the sedation unit.
importance of keeping greese and oil away from compressed gas
potentially explosive mixture Once the grease or oil ignites, either N2O or O2, although nonflammable, will support combustion. Temperature and pressure within the cylinder increase even further producing: 1. an explosion 2. a melting of the valve stem of the cylinder, releasing the contents of the cylinder Death and serious injuries have occurred
Regulators
reducing valves Located between compressed-gas cylinder and flowmeter
minimum oxygen percentage
sets a minimum of 30% O2 on sedation units - this is a safety feature of the units. HOWEVER, remember that the minimum amount of O2 that must be used when administering N2O must be 20% O2.
Second disadvantage for demand flow
the lack of accuracy of the mixer valve Percentage of gas delivered is not accurate over the full range of delivery (0% to 100% N2O)
Pin index system
the safety system used to ensure that the proper regulator is used for a specific gas, such as oxygen makes it physically impossible to attach an N2O cylinder to the yoke attachment for O2. Consists of a series of pins, the configuration that differs for each compressed gas and matching series of holes on the cylinders.
alarm
there is a shutting off of gas flows on the unit, the alarm system is activated
Reservoir bag function
to provide a reservoir if respiratory demands of patient exceed gas flow, as when a patient draws a deep breath Second use - serves as a monitoring device for respiration, will inflate and deflate with exhalations and inhalations Third potential use - can provide O2 during assisted ventilation but usually only practical with full-face mask
