KYJ6 - IE ratio
Knowing your Jargon.
In this episode of KYJ (Knowing your Jargon, not to be confused with KY Jelly), we look at one of the forgotten respiratory assessment data. The humble IE ratio is often observed, yet rarely recorded. It stands for Inspiratory :Expiratory. It is a ratio of time that it takes for a person to inhale a breath, vs the time it takes to exhale.
Normally we take 1.5 to twice as long to breathe out than we do to breathe in. Therefore our normal IE Ratio is expressed as between 1:1.5 to 1:2 .
This simply means if it took you one second to breathe in, it would be normally expected that you'd take 1.5 - 2 secs to breathe out. This becomes a function of lung compliance and air way obstruction.
Lets consider two extremes .
Scenario 1 a high IE ratio of 3:1
In this example, a person takes 3 times longer to inhale than exhale. In upper respiratory stridor eg croup, or foreign body airway obstructions, the difficulty might be getting a lung full in. We see this in circumferential chest burns also; and if severe enough, a surgical skin release procedure called Escarotomy, is performed to release pressure.
Scenario 2
In Low IE ratios, the patient has no trouble breathing in, but may exhibit difficulty exhaling due to lower airways restriction, or bronchospasm. A classic example is the acute Asthma patient who may have breathing so laboured, that an IE ratio is something like 1:5. It takes 5 times longer to exhale that inhale. In children with restrictive airways diseases like asthma, the lower the IE ratio, the more exhausted they get. Gas trapping occurs followed by respiratory failure and arrest.
... Just a KYJ quicky tonight.
Keep rocking the jargon.
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