733 ECG and Spirometry

what is an ECG measuring

cardiac cells that generate a small electrical voltage as they depolarize and repolarize

what does the P wave correspond with

atrial depolarization/contraction

what does the QRS wave correspond with

ventricle depolarization/contraction

what does the T wave correspond wth

ventricle repolarization

what is a lead

a specified electrical “viewing angle” of the heart- the voltage difference measured between two points on the body

where is the most important lead in telemetry

lead 2- in line with electrical access of the heart and captures the largest, clearest deflections

what does spirometry measure

the volume and flow of air moved during a forced breathing maneuver

Boyle’s Law during inhalation

increased volume → decrease pressure & air flows in

Boyle’s Law during exhalation

decrease volume → increase pressure & air flows out

volume in spirometry

includes total lung capacity, residual volume, and forced vital capacity

what is volume driven by

compliance- how easily tissue stretches

elastic recoil- the lung’s passive spring back

flow

foreced expiration volume 1, forced vital capacity, loop shape

what is flow driven by

airway resistance and how much of the airway diameter restricts airflow

what are 3 things that determine stroke volume

preload, contractility, afterload

does the heart muscle receive its own blood supply mainly during systole or diastole- and why does it matter?

Diastole because during systole coronary arteries are restricted but open during diastole

what determines airway resistance?

airway muscle tone and inflammation

airflow and lung volume relationship

are physiologically separate properties- one can be abnormal without the other

FEV1/FVC ratio

The amount of air you can force out in one second over the total air you can push out in one full breath