Medical Gases Flashcards
1
Q
What is the average barometric pressure at sea level?
A
760 mmHg
2
Q
Oxygen properties
A
colorless, tasteless, transparent, very common in nature.
3
Q
Oxygen supports what?
A
combustion
4
Q
Are there any contraindications to oxygen?
A
NONE
5
Q
What are some hazards and complications of excessive oxygenation?
A
retinopathy of prematurity, Oxygen toxicity, absorption atelectasis, hypoventilation(rare)
6
Q
What are some hazards and complications of insufficient oxygenation?
A
cellular damage, neurological damage, cardiac failure/death
7
Q
Oxygen is considered what?
A
a drug
8
Q
Carbon Dioxide properties
A
colorless, transparent, very slight taste and odor. Waste product of respiration, cannot support life, will NOT burn
9
Q
Carbon dioxide must be used how for medical purposes?
A
Mixture of carbon dioxide and oxygen (carbogen)
10
Q
Hazards and complications of medical carbogen
A
headache, dizziness, dyspnea, disorientation, nausea, and hypertension
11
Q
Helium properties
A
colorless, odorless, tasteless, transparent, does not support life
12
Q
Medical Helium indication
A
mixed with oxygen to make breathing gas less dense for patients with sever airway obstruction (severe asthma)
13
Q
Nitric Oxide properties
A
colorless, tasteless, transparent, slight metallic odor, unstable, does not support life
14
Q
Nitric Oxide is very commonly used where?
A
ICU setting
15
Q
Contraindications to medical helium
A
none its inert
16
Q
Nitric Oxide is a powerful what?
A
vasodilator
17
Q
Contraindications for Nitric Oxide
A
not used in some patients with some congenital heart defects
18
Q
Hazards and Complications of Nitric Oxide
A
used in very small quantites, patients are gradually weaned off it,
19
Q
Nitrous Oxide properties
A
colorless, odorless, tasteless, and transparent, non flammable but it supports combustion
20
Q
What is Nitrous Oxide used for?
A
CNS depressant and anesthetic (most common)
21
Q
Nitrous Oxide is sometimes called what?
A
laughing gas
22
Q
Contraindications for Nitrous Oxide
A
none except any known allergies or sensitivity to this gas
23
Q
Hazards and Complications to Nitrous Oxide
A
Must be used with Oxygen, very high incidence rates of misuse
24
Q
Medical Air (room air) properties
A
ordorless, colorless, transparent, tasteless
25
What is the second most common gas given to patients?
medical air
26
Nitrogen properties
nonflammable, non toxic
27
What is the primary use for nitrogen in medical field?
operate pneumatic power tools in surgery
28
What are the two flammable gases?
cyclopropane and ethylene
29
What are the 3 nonflammable gases?
Nitrogen, Carbon Dioxide and Helium
30
Fractional distillation was invented by who?
Carl von Linde
31
What is fractional distillation?
cheapest and most common way of manufacturing oxygen
32
Fractional distillation procedure is what?
air is changed to a liquid by a decrease in pressure, and temperature. As air warms Nitrogen escapes first. This process is repeated several times until oxygen is pure
33
Bulk medical oxygen definition
any oxygen system that can hold 20,000 cubic ft at one site
34
Liquid Systems
very common and best way to store.
35
How are liquid systems built?
must have safety reducing valve. Vaporizing columns are flexible to allow for expansion and contraction due to temp changes
36
Gas manifold
a series of cylinder tanks linked to each other
37
Continuous system
one main reservoir, periodically filled. Reserve supply with 1 days gas supply
38
Alternating System
two gas sources, one operates at a time, while other can be refilled or replaced. Reserve supply with 1 days gas, does not normally operate.
39
Piping Systems
must be capable of delivering 50 psi to each outlet at max flow rates
40
Zone valves
used in cases of emergency or maintenance and they can temporally shut off
41
How are zone valves placed in a hospital?
accessible to general public, must be in boxes with windows. Valves must be labeled to avoid accidental shut off.
42
Station or wall outlet
must deliver 50 psi at all outlets simultaneously and must have label for type of gas being delivered.
43
what is the connection from wall outlet to equipment called?
Quick Connects
44
What materials are cylinders constructed with?
steel or steel alloy, aluminum, and aluminum with epoxy
45
Storage and distribution of medical gases
safe use of cylinders, cylinder markings, color coding, labeling, and standardized testing
46
What are the large common sizes for cylinders?
H, K and M
47
What are the small common sizes for cylinders?
E
48
Hydrostatic testing
underwater testing and then over pressurized and checked to see if cylinder expands. Steel is every 5-10 years and aluminum is every 5 years
49
Visual inspection
use a scope to check cylinder
50
Dead Ring Test
flick cylinder with wrench to see if it rings
51
Color coding of cylinders
decreases the chance of giving the wrong gas to patients
52
Color code for oxygen
green
53
Color code for air
yellow
54
color code for nitrogen
black
55
color code for nitrogen/oxygen
black/green
56
color code for carbon dioxide
grey
57
color code for helium
brown
58
color code for nitrous oxide
blue
59
color code for cyclopropane
orange
60
color code for ethylenal
red
61
What three must agree to prevent giving patient wrong medical gas?
color coding, labels, and connection devices
62
American Standard Safety System
large cylinders with pressures greater than 1500 psi, H,K, G, M, threaded
63
Pin Index Safety System
small cylinders (E and smaller) pressures greater than 1500. Two pins on regulator and are inserted into cylinder valve.
64
Diameter Index Safety System
low pressure gas connections (less than 200 psi) wall outlets, regulator outlets, and quick connect adapters
65
Pressure Relief valves
every cylinder has to have one. Means of decreasing internal pressure in the cylinder in the event of a malfunction
66
What are the three types of pressure relief valves
spring loaded, frangible disk, and fusible plug
67
What is the pressure most gas cylinders of any size contain?
2200 psi
68
Grab and Go cylinders have what permanently attached?
regulator
69
What is "cracking" a cylinder?
slow open and reclose the cylinder valve. This removes dust, dirt, or rust that may cause malfunction.
70
Cylinder valve factors
E (622 liters/2200psi) =0.28 L/psi
| H/k (6900 liters/2200) =3.14 L/psi
71
What is the equation used to find the number of minutes left in cylinder?
PSI X cylinder factor/Rate of use LPM
72
Reducing valve definition
reduces gas pressure from high, variable pressure to a lower more constant pressure
73
Regulator definition
combination of reducing valve plus a flowmeter.
74
Principle of operation definition
gas pressure vs. spring tension. When 2 opposing forces reach equilibrium, final outlet pressure is achieved
75
What are the two types of regulators?
preset and adjustable
76
Preset regulator
outlet pressure is fixed. Usually 50 psi
77
Adjustable regulator
outlet pressure is variable and can get adjusted by the user
78
Single Stage
pressure drops in one step (stage) from cylinder to outlet pressure (2200-50 psi)
79
Multiple Stage
pressure drops 2 or more specific stages before reaching out
80
Flowmeter definition
used to measure and dispense gas going to patient
81
Bourdon Gauge style flowmeter
actually measure pressure but is calibrate to read flow (based on pressure) without restrictions. Handy when transporting.
82
Thorpe tube Non compensated
does not read accurately is restriction to flow is added
83
Thorpe tube back pressure compensated
always reads accurately even if restriction is added
84
What are the three ways to determine if a flowmeter is back pressure compensated?
read label
take apart to determine position of needle valve to float
turn flow meter off, plug into wall outlet, If float jumps its back pressure compensated
85
Flow Restrictors
adding restrictions to flow. Used in home liquid oxygen units, on Grab and Go and on some gas regulators.
86
PaO2
partial pressure of oxygen in arterial blood, requires a needle stick and run through blood analyzer. Measures amount of oxygen dissolved in plasma.
87
SaO2
saturation of oxygen in arterial blood. Measures all species of hemoglobin. Requires arterial blood sample and co-oximeter
88
SpO2
saturation of oxygen predicted by pulse oximetery. Indirect measurement by comparing light absorption during systole and diastole in a well perfused capillary bed.
89
Purpose of pulse oximetry
non invasive estimate of arterial oxygen saturation using select wave lengths of light.
90
Functional Hemoglobin
measurement of percentage of hemoglobin capable of carrying oxygen. Pulse oximeter is capable of doing this.
91
Fractional Hemoglobin
True SaO2 via a co-oximeter. This compares the hemoglobin carrying oxygen against all other hemoglobin types for a more accurate measurement(requires needle stick)
92
Range of error for a pule oximeter
plus/minus 5
93
Haldane effect
is pH changes the PaO2 remains the same but the SpO2 becomes lower
94
Reasons a pulse oximeter could not read accurately
poor perfusion, dark skin, nail polish, ambient light, motion artifact, dyes, anemia
95
How much hemoglobin is available for oxygen transport
15%
96
Things to consider when picking a site for pulse oximeter to go on
warm, clean, dry, thin, well perfused, and a relatively still area
97
Types of probes for pulse oximeter
disposable vs. nondisposable, finger, ear, wrap, reflective
98
Advantages to pulse oximeter
continuous, instant results, non invasive, comfortable, simple and portable
99
Disadvantages to pulse oximeter
false high readings, only oxygenation assessed, cross contamination, potential tissue injury
100
Signs and symptoms of acute hypoxemia
tachycardia, tachynpea, cyanosis, paleness, poor perfusion, hypertension, restlessness, dyspnea, disorientation, lethargy, labored breathing, coma
101
Signs and symptoms of chronic hypoxemia
same as acute plus loss of coordination, sleepyness, headaches, clubbing of digits
102
What are some conditions or diseases requiring oxygen
heart attack, trauma, congestive heart failure, respiratory disease, anaphylaxis, surgical procedures, labor and delivery
103
What are some signs of good or improving oxygenation?
normal vital signs, good skin color, capillary refill <2 secs, good pulses, good skin temp, normal urine output, normal CNS status
104
What does A+O x 3 mean?
patient knows name, date, and place
105
Low flow devices definition
concentration or percent O2 varies with patients breathing pattern
106
Factors that will affect the percentage of oxygen the patient receives from low flow equipment are?
Tidal volume, rate, inspiratory flowrate, anatomic reservoir, and respiratory pattern
107
Nasal catheter
low flow, not used much anymore, flowrates 6-10 LPM, 22-44% oxygen
108
Nasal cannula
low flow, most common device, Adults 0.5-6 LPM, Peds 0.1-2 LMP, convenient and easy to use, 22-44% oxygen
109
Simple mask
Mask is less comfortable, 5-10 LPM, 35-50% oxygen
110
Partial rebreather
6-10 LPM, 40-70% oxygen
111
Non rebreather
10 LPM and up (usually 15) 60-80% oxygen
112
Trans tracheal oxygen
Used for patients on long term oxygen, surgically placed, ..25-4 LPM, 22-50% oxygen
113
Rounding of patients
Usually done every 4 hours, checks orders, observe patients, check equipment
114
High flow definition
Fixed performance, can predict patients oxygen percentages that's provided to them of all inspired gas. Exceeds patients inspiratory flow rate
115
Bernoulli effect
As gas flow thru a tube the lateral pressure is inversely proportional to the velocity
116
Venturi effect
Sucking theory, addition of a tube of gradually increasing diameter in the direction of flow near a restriction (jet orifice) will restore the lateral pressure to it's pre-restriction pressure
117
Viscous shearing force
Dragging force, as moving fluid or gas encounters a stationary fluid or gas, the friction between the two will cause the moving fluid to accelerate the stationary fluid.
118
Entrainment principles
1. The tighter the restriction:
- greater inc. in velocity
- greater dec. in lateral pressure
- greater pressure gradient between pre and post restrictions
2. If entrainment port size is held constant more of the second gas will be entrained with a smaller jet than a larger one
3. If entrainment port size is increased and the jet size is held constant more of the second gas will be entrained
4. Any restriction to flow at distal end of tube will cause back pressure which can decrease entrainment
119
Venturi mask
High flow, suppose to deliver a pre mixed concentration of oxygen at a flow rate that exceeds the patients inspiratory flow rate
120
What is the typical flow rate for adults?
25-30 LPM at rest
121
What do we try to keep the flow rates at?
Greater than 40 LPM
122
Ratio for 24 LPM
25:1
123
ration for 28 LPM
10:1
124
Ratio for 30 LPM
8:1
125
Ratio for 31 LPM
7:1
126
Ratio for 35 LPM
5:1
127
Ratio for 40 LPM
3:1
128
Ratio for 50 LPM
2:1
129
Construction of small version bulk liquid reservoirs
- insulation to maintain lower temp
- pressure relief valve
- vaporizing coils
- usually large reservoir and a smaller portable unit
130
Portable units provides how many hours of oxygen depending on flow rate and temp?
8-12 hours
131
Examples of small bulk liquid reservoirs
- linde walker
- companion
- liberator/spirit
- Helios (Puritan Bennett)
132
What are some benefits to liquid oxygen respiratory systems?
- promotes patient ambulation
- improved quality of life
- 100% pure medical oxygen
- saves $$
- lower dealer maintenance
133
Handling recommendations liquid oxygen systems
- do not store in enclosed space
- keep upright
- keep away from heat
- let spills evaporate
- no smoking
134
Purpose of concentrators
Separates oxygen from environmental air and delivers to patient as supplemental oxygen
135
Molecular sieve concentrators is what?
Most common method used
136
How does molecular sieve concentrator work?
Draws in and compresses room air, zeolite crystals absorb nitrogen, oxygen is collected and held for patient
137
Membrane concentrator
Provides humidity and moderate amounts of oxygen using a semi permeable membrane
138
FIO2 for membrane concentrators
Approx. 30-40%
139
Advantages to concentrators
- patient less dependent on home care company
- less expensive
- less high pressure risks
- less fire hazard risk
140
Disadvantages to concentrators
- less portable
- requires electricity
- must have tanks for emergencies
- higher flows=lower purity of oxygen
141
Air compressor purpose
Compressed room air to provide medical devices such as nebs, vents, or hospital piped in air
142
What are the 3 styles of compressors?
Piston
Diaphragm
Rotary
143
Piston style compressor
More common, used for large systems like hospital
144
Diaphragm style compressor
Close to design as piston, used for small compressors like nebs
145
Rotary style compressor
More commonly used in mechanical vents. Very noisy
146
What are air compressors powered by?
Electricity or battery
147
Oxygen blender purpose
Provide a pre mixed concentrating of oxygen to patient
148
Oxygen blender provides how much oxygen?
21-100%
149
Oxygen blenders are usually already on what piece of equipment?
Mechanical ventilators
150
Operation of oxygen blender
Requires 50 psi air and oxygen source gases and mixed by a proportioning valve
