Assessment of Lung Ventilation (Nursing)

00:01 So how do we assess ventilation? Ventilation can be assessed using several respiratory volumes.

00:09 These respiratory volumes can then be combined in order to calculate something called respiratory capacities.

00:16 It is these capacities which give us information about a person's respiratory status.

00:23 Respiratory volumes and capacities are usually abnormal and people with certain pulmonary disorders and the instrument that we use to measure this is known as a spirometer.

00:35 Now the olds spirometer were pretty clunky and cumbersome to use but now mostly spirometer are used electronically.

00:45 So first, let's start with our respiratory volumes because these are going to be important in determining our respiratory capacities.

00:52 There are four main respiratory volumes.

00:55 We have the title volume, which is just the amount of air moving in and out of the lungs in a normal breath.

01:02 This is usually about 500 milliliters.

01:06 Then we have our inspiratory reserve volume.

01:09 This is the amount of air that can be inspired forcibly beyond the title volume.

01:15 So for example, if your doctor were to tell you to take a deep breath.

01:20 Opposite to this we have our expiratory reserve volume.

01:24 This is the amount of air that can be forcibly expelled from the lungs.

01:29 For example, if the doctor were to tell you to take a deep breath out and then we have our residual volume.

01:37 This is the amount of air that always remains in the lungs.

01:41 The lungs are never completely empty, And the reason why is because we need to keep our alveoli inflated or open, so there's always a residual amount of air in the lungs at all times.

01:55 So we combined these volumes in order to determine different capacities of the lungs.

02:01 To determine our inspiratory capacity, w e look at the sum of our tidal volume and our inspiratory reserve volume.

02:11 In order to determine our functional residual capacity.

02:15 We look at the residual volume as well as the expiratory reserve volume.

02:22 We determine the vital capacity of the lung by looking at our title volume and adding it to our inspiratory reserve volume and our expiratory reserve volume.

02:35 And finally our total lung capacity as a sum of all four of the different respiratory volumes.

02:46 So this is also depicted here in this chart and it says exactly what I said before where are four total volumes can be used to determine different types of capacity.

02:59 So volumes and capacities are going to be a little different between males and females.

03:04 So while the title volume is generally the same for all adults whether male or female the other volumes and subsequent capacities are usually lower and females than they are in males.

03:21 So another component of the lungs is also the anatomical dead space or just dead space in general.

03:27 And are anatomical dead space, this is not going to contribute to our gas exchange and it's just going to consist of air that is kind of always sitting in the lungs at all times.

03:39 This is usually about a hundred and fifty milliliters out of the 500 milliliters of air that we take in and out or our title volume.

03:48 We also have a dead space known as the alveolar dead space and in this space, it is occupied by non-functional alveoli.

03:57 These usually occur due to a collapse of the alveoli or some type of obstruction.

04:04 The total dead space is going to be the total of the anatomical and the alveolar dead space in the lungs.