pressure Flashcards
1 mmHg=___cm H20
1 mmHg=1.35 cm H20
one (1) atm (atmosphere) equals what in:
- mmhg:
- gm/cm2:
- Bar:
- mBar:
- hPa:
- psi:
- kPa:
one (1) atm (atmosphere) equals what in:
- mmhg: 760
- gm/cm2: 1033
- Bar: 1.01325
- mBar: 1013
- hPa: 1000
- psi: 14.7
- kPa: 101.325
1 Bar= ____dynes/cm2
1 bar=106 dynes/cm2
1 pascal(Pa)=___
1 Pascal=1 newton/meters2
1 kiloPascal (kPa)=_____ Pa
1 kiloPascal=1000 Pa
- 1 atm= _____Pa
(remember a Pa is a very small unit) - what is a hPa?
- thererfore, how many hPa in 1 atm?
- 1 atm=100,000 Pa
- a hPa is a hectopascal (10(2) Pa) or 100 Pa
- 1,000 hPa in 1 atm
1 bar=____atm
1 bar=1 atm
- what is psia?
- what is psig?
- psig vs psia; what is the difference?
- psia is absolute psi and has a zero point that is a vacum
- psig is psi on a guage and its zero point is atmospheric pressure
- psia=psig+1 atm (psia is bigger)
___atm=___mmhg=___Bar=___mBar=___hPa=___psi=___kPa
1atm=760mmHg=1Bar=1000mBar=1000hPa= 14.7Psi=100kPa
how to calculate atmospheric pressure:
at sea level the atmospheric pressure is 29.9 inches of mercury
(29.9 inches Hg x 25.4 mm per inch=760 mmhg)
(1 inch=2.54 cm=25.4 mm)
how does atmospheric pressure change at sea level compared to high altitudes?
21% oxygen at sea level has a partial pressure of 159 mmHg
(760 x .21= 159.6)
21% oxygen at high altitude has a partial pressure of 80mmHg
–because the atmospheric pressure is only 380 mmHg–
(380 x .21=79.8 or 80)
(so divide the known % of the gas by the given atmospheric pressure to get your partial pressure.
- what is the pressure generated by a 2 ml syringe?
2. a 20 ml syringe?
- 500 kPa (5 atm or 5x 760 mmHg= 3,800 mmHg)
2. 100 kPa (1 atm)
why should you inject distally and slowly for Beir block?
if LA is pushed fast, the force of the pressure of the syringe may be greater than the cuff and push LA systemically.
- where is a Bourdon guage used?
- how does it work?
- Bourdon guage has what is called an “aneroid” manometer; what does this mean?
- used for higher than 1 atm pressure (E tanks)
- high pressure of gas causes a tube to uncoil and move a pointer
- aneroid means without liquid (greek)
what monitors pressure on the ADU?
a D-Lite sensor which monitors airway pressure
what Low pressure conditions are detected by pressure monitoring (D-lite or whatever)?
Low peak inspiratory pressures:
- disconnect
- major leak
- failure of fresh gas flow
- tracheal tube leak/ extubation
- ventilator failure, disconnected vent, incorrect vent setting
- scavenger malfunction
- increased compliance
- reduced resistance
what other pressure conditions are detected by pressure monitoring:
- high pressure
- sustained pressure
- sub ambient pressure
- low battery
how can the pressure alarm be fooled?
- alarm not on
- threshold too low
- peep on
- elbow obstructed
- partial extubation
- disconnect
- what should be your low limit on your peak pressure?
2. how do you test the alarm?
- 8-10 cm H2O
2. disconnect the alarm to see if alarm rings
atmospheres:
how many pascals does each one take to make 1 atm?
1. pascals
2. hecto pascals
3. kilo pascals
4. how do the pascals relate (? kpa = ? hpa = ? pa)
- 100,000 pa=1 atm
- 1,000 hpa= 1 atm
- 100 kpa=1 atm
- (1 kpa = 10 hpa = 1,000 pa)
how many bars…
- how many pka in 1 bar?
- how many dynes in 1 bar?
- how many mbars in 1 bar?
- how many atm in 1 bar?
- 100 kpa in 1 bar
- 106 dynes/cm squared in 1 bar
- 1013 mbars in 1 bar
- 1 atm = 1.01 bar
