Principles EKG 1 Flashcards
What is monitoring?
Monitoring is making repeated or continuous observations or measurements of the patient, their physiologic function, and the function of life supporting equipment, for the purpose of guiding management decisions, including when to make therapeutic interventions and assessments of those interventions
What is electrocardiography?
Source of EMF in a 3-D space that is projected on planer surfaces
What three things do we look at on the ECG for anesthesia?
Rate
rhythm
ST segments
Where does the myocardial electrical activity start?
Initiates at the SA node
What does the SA node stand for and what does it mean?
Sinal atrial node
Means that the activity is sinus in rhythm
What is the electrically conductive tissue inside the body?
Volume conductors
Ie. Blood, pericardial fluid, interstitial fluid
How does air and other gases affect conductivity?
Air acts as a block in conductance
True or false: pores and capacitive coupling provide electrical access to the volume conductors from outside the body.
True
How are the half cell potentials that are produced between the skin and electrodes overcome?
By using amplifiers so that the half cell potentials are canceled out or blocked
Which amplifier is used so that the effects of the two half cell potentials are canceled out
Differential input DC amplifier
Which amplifier is used so that the DC voltage is blocked?
AC coupled amplifier
What type of amplifiers or most used in the OR today?
AC coupled differential amplifiers
Because of their stable half cell potential which electrodes are used in most medical applications
Silver-silver chloride (Ag-AgCl)
What is the most common mechanism that creates artifact signals?(That is signal’s that could possibly obscured the real signal)
Electrode slippage
What is the most common type of electrode used today?
Column electrodes
These keep the electrode at a fixed distance from the skin
What is one of the original type of electrodes used that connects a metallic plate that is held to the skin by rubber strap
Plate electrodes
What is an original type of electrode that is similar to the plate electrodes but most often is used as a chest electrode
Suction cup electrodes
What was the main difference in the plate electrodes and the suction cup electrodes
The plate electrodes went on the extremities
The suction cup most often went to the patient’s chest
EEG electrodes are much more sensitive than ECG electrodes because of what
Because the typical EEG electrodes are either a needle or a concave disk made of either gold or silver that is held by thick paste that is more conductive than what is used on the ECG
The “backpack” electrodes and the MRI electrodes have which side effect
They are not good for ST monitoring
What is the standard range of width of the clinical electrode used today
1 cm
The first electrometer used in 1887 by Agustus Waller used what
A 20 µ glass capillary tube filled with Mercury and was floating in sulfuric acid