8-10
nitrite (methemoglobin) poisonings, although pulse oximetry will be normal.
- Record all findings in the patient’s medical record.
What Not To Do:
Do not fail to recognize explanations (below) for false readings, which are common:
Excessive ambient light on the oximeter’s probe.
Hypotension - causes vasoconstriction of capillary beds
Hypothermia – causes vasoconstriction of capillary beds
Patient’s use of vasoconstrictive drugs.
Patient’s use of nail polish.
Jaundice.
Very dark pigmented skin (choose area that has less pigment – finger tips, toes, etc.)
Procedure: 3-Lead Electrocardiography
18D Skills and Training Manual, reviewed by COL Warren Whitlock, MC, USA and LTC Richard Broadhurst,
MC, ARNGWhat: Guidelines on preparing for and conducting an EKG using only three leads.
When: EKG is used for diagnostic and monitoring purposes.
Diagnose: Metabolic and toxic disorders of the heart. (example: high potassium, low calcium, toxic quinidine
or digoxin), chamber enlargement (example: ventricular and atrial enlargement), acute myocardial infarction
and myocardial ischemia (myocardial infarction or angina), or arrythmias and conduction system abnormalities
(example: bundle branch blocks seen in Chagas’ cardiomyopathy).
Monitor: Therapeutic changes made in any of the above can be monitored by EKG changes.
What You Need: A cardiac monitor/defibrillator, EKG paper, electrodes, EKG paste (conductive gel), heart
rate calculator ruler, alcohol prep pads, surgical lubricant, drapes, and tape.
What To Do:
NOTE: A 3-lead EKG is used to monitor the heart solely for dysrhythmia. The following
information can be obtained from using Lead II:
Rate: How fast the heart is beating (electrically).
Rhythm: Life-threatening dysrhythmias.
Intervals: How long it is taking to conduct an impulse through the parts of the heart.
The following information cannot be obtained from using Lead II:
The presence or location of an infarct.
Axis deviation or chamber enlargement.
Right-to-left differences in the conduction impulse formation.
The quality or presence of pumping action.
- Prepare the equipment.
a. Read the manufacturer’s instructions for proper use of the equipment on hand if not familiar with it.
b. Plug the machine into a wall outlet that is grounded.
c. Turn the power switch ON and allow the machine to perform its self-checks and warm up for
5 minutes.
d. Check the machine’s graph paper supply.
e. Verify that the machine is set on the standard settings: paper speed at 25 mm/sec; amplitude
at 10 mm/mv.
f. Verify that all other equipment is on hand: EKG paste, 3 clean electrodes, alcohol pads, drapes
or towels.