RCT ch 41-42 test #2 chapters 41 and low flow of 42 (1st
half) Questions With Complete Solutions
Flow Restrictor
simplest and least expensive flowmeter device. fixed orifice
calibrated to deliver a specific flow at a constant pressure (50
psig).
Bourdon gauge
-Used with an adjustable pressure reducing valve
-Uses a fixed orifice
-Operates under varying pressures.
Fixed orifice, variable pressure flow metering device
-Measures pressure changes and liter flow
-Use to be the best choice for patient transfers since it is not
affected by gravity like flow restrictors
-Best choice when you cant maintain your flowmeter in the
upright position. Common during transport
Integrated oxygen cylinders
~includes Grab'n Go System
~eliminates need for separate oxygen tanks, Bourdon gauge
regulators, and oxygen keys/wrenches
~flow is selected and oxygen tubing to system can simply be
connected to patient
-alerts are activated when cylinder duration falls below 15 mins
Thorpe Tube (measures true flow)
,Attached to 50psig source
Preset pressure reducing valve
Bedside station outlet
-variable orifice, constant pressure flow metering device.
-Key component is a tapered transparent tube with a float
Diameter increase from bottom to top
-Gas flow suspends the float against the force of gravity.
-Reading flow: Compare float position to an adjacent calibrated
scale.
Normally L/min
-Compared to a bourdon gauge (which measures pressure) a
Thorp tube measure flow.
-Float rises, more room (like increasing the orifice) for flow to
get through thus higher flow
Uncompensated Thorpe Tube
•Calibrated in liters per minute at atmospheric pressure (without
restriction)
•Gas from 50-psig source flows into meter at rate controlled by
needle valve located before flow tube
Pressure Compensated Thorpe Tube
~prevents changes in downstream resistance, or back pressure,
from affecting meter accuracy
~calibrated at 50-psig instead of at atmospheric pressure
~flow control needle valve placed after (distal to) flow tube
~gravity dependent; not ideal for patient transport
Pressure Compensation
, design that prevents changes in downstream resistance, or back
pressure, from affecting meter accuracy
goal of O2 therapy
to maintain adequate tissue oxygenation while minimizing
cardiopulmonary work
Clinical objectives for O2 therapy
-Correct documented or suspected acute hypoxemia
-Decrease symptoms associated with chronic hypoxemia
-Decrease the workload hypoxemia imposes on the
cardiopulmonary system
where is it common to see high CO2s and low PAO2s?
patients with COPD
Polycythemia
excess of red blood cells
what does hypoxemia cause in the body?
pulmonary vasoconstriction & pulmonary hypertension
what increases the workload of the right side of the heart?
pulmonary vasoconstriction & hypertension
Chronic hypoxemia can lead to what?
right ventricular failure (corpulmonale)
What can O2 therapy decrease?
right ventricular workload and reverse pulmonary
vasoconstriction
half) Questions With Complete Solutions
Flow Restrictor
simplest and least expensive flowmeter device. fixed orifice
calibrated to deliver a specific flow at a constant pressure (50
psig).
Bourdon gauge
-Used with an adjustable pressure reducing valve
-Uses a fixed orifice
-Operates under varying pressures.
Fixed orifice, variable pressure flow metering device
-Measures pressure changes and liter flow
-Use to be the best choice for patient transfers since it is not
affected by gravity like flow restrictors
-Best choice when you cant maintain your flowmeter in the
upright position. Common during transport
Integrated oxygen cylinders
~includes Grab'n Go System
~eliminates need for separate oxygen tanks, Bourdon gauge
regulators, and oxygen keys/wrenches
~flow is selected and oxygen tubing to system can simply be
connected to patient
-alerts are activated when cylinder duration falls below 15 mins
Thorpe Tube (measures true flow)
,Attached to 50psig source
Preset pressure reducing valve
Bedside station outlet
-variable orifice, constant pressure flow metering device.
-Key component is a tapered transparent tube with a float
Diameter increase from bottom to top
-Gas flow suspends the float against the force of gravity.
-Reading flow: Compare float position to an adjacent calibrated
scale.
Normally L/min
-Compared to a bourdon gauge (which measures pressure) a
Thorp tube measure flow.
-Float rises, more room (like increasing the orifice) for flow to
get through thus higher flow
Uncompensated Thorpe Tube
•Calibrated in liters per minute at atmospheric pressure (without
restriction)
•Gas from 50-psig source flows into meter at rate controlled by
needle valve located before flow tube
Pressure Compensated Thorpe Tube
~prevents changes in downstream resistance, or back pressure,
from affecting meter accuracy
~calibrated at 50-psig instead of at atmospheric pressure
~flow control needle valve placed after (distal to) flow tube
~gravity dependent; not ideal for patient transport
Pressure Compensation
, design that prevents changes in downstream resistance, or back
pressure, from affecting meter accuracy
goal of O2 therapy
to maintain adequate tissue oxygenation while minimizing
cardiopulmonary work
Clinical objectives for O2 therapy
-Correct documented or suspected acute hypoxemia
-Decrease symptoms associated with chronic hypoxemia
-Decrease the workload hypoxemia imposes on the
cardiopulmonary system
where is it common to see high CO2s and low PAO2s?
patients with COPD
Polycythemia
excess of red blood cells
what does hypoxemia cause in the body?
pulmonary vasoconstriction & pulmonary hypertension
what increases the workload of the right side of the heart?
pulmonary vasoconstriction & hypertension
Chronic hypoxemia can lead to what?
right ventricular failure (corpulmonale)
What can O2 therapy decrease?
right ventricular workload and reverse pulmonary
vasoconstriction
