Zeroing is
designed to negate the influence of external pressures
, such as atmospheric pressure, on the monitoring system. Zeroing the arterial line ensures that only the actual pressures from the patient will be measured by the transducer, thus providing accurate data on which to base treatment decisions.
Why do you zero the transducer?
Zeroing the Transducer
By opening the stopcock to air, the
monitoring system uses atmospheric pressure as a reference
for zero. Pressing the zero button negates the effects of atmospheric pressure so that the pressure values reflect only those of the patient.
When should transducer be zeroed?
The device is zeroed when
the air-fluid interface is opened to atmospheric pressure
(otherwise it would read diastolic blood pressures of ~ 760mmHg).
What is a zero transducer?
To zero the line, the 3-way tap at the transducer is opened so that the
transducer is exposed to atmospheric pressure
. The ‘zero pressure’ button is pressed on the monitor (thus the monitor has a reference for pressure that equates to zero).
Why is Phlebostatic axis important?
The phlebostatic axis is
the reference point for zeroing the hemodynamic monitoring device
. This reference point is important because it helps to ensure the accuracy of the various pressure readings. Nurses must ensure the accuracy of their hemodynamic monitoring devices.
Where should a line transducer be?
For patients who are lying down, the transducer is usually positioned at the
level of the right atrium or the midaxillary line
. For patients who are sitting, the cerebral pressure is less than at the level of the heart, so the transducer should be placed at the level of the brain.
How long should an art line last?
Arterial lines are generally kept in place for a short period, until you feel better and your condition stabilizes. You will stay in a critical care area where you are closely monitored, usually an intensive care unit (ICU). Your provider may insert a new arterial line if you need it for more than
five days
.
Can you run fluids through an arterial line?
Arterial lines are connected to a bedside monitor to continuously display both the waveform and pressure from within the artery (Image 2). prevent blood from clotting in an arterial catheter, a
slow continuous
infusion of fluid is run into the catheter (at 2-3 ml per hour).
How does a transducer work?
A transducer
receives sequences of high voltage electrical pulses called transmit pulses from the echosounder
. … When the wave of sound bounces back, the transducer acts as a microphone. It receives the sound wave during the time between each transmit pulse and converts it back into electrical energy.
What is a normal CVP?
A normal central venous pressure reading is
between 8 to 12 mmHg
. This value is altered by volume status and/or venous compliance.
What is CVP?
From Wikipedia, the free encyclopedia.
Central venous pressure
(CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system.
How do you level a CVP transducer?
CVP is usually recorded at the
mid-axillary line
where the manometer arm or transducer is level with the phlebostatic axis. This is where the fourth intercostal space and mid-axillary line cross each other allowing the measurement to be as close to the right atrium as possible.
What causes Overdamping?
Inaccurate damping can lead to inappropriate treatment:
Overdamping (defined as when the oscillations following the downstroke are sluggish and can underestimate systolic pressure or overestimate diastolic pressure). Causes include:
Loose connections
.
Air bubbles
.
What causes whip in an arterial line?
Resonance or whip causes falsely increased systolic readings and falsely decreased diastolic readings. It occurs when the system’s frequency of oscillation
(i.e., heart rate) matches the system’s natural frequency of vibration
causing whip in the signal.
What causes a dampened waveform?
There are a number of causes of an over-damped waveform.
Tiny air bubbles in the tubing
, a clot at the tip of the catheter, tubing that is “too” stiff or kinked and / or a catheter that is positioned against the wall of the blood vessel.
