 Hi and welcome to nursing school explained that this video about respiratory terms and physiology. This video is intended to be a review for more of the respiratory kind of like critical care scenarios such as ARDS, Acute Respiratory Stress Syndrome, Acute Respiratory Failure and so forth. And really what I'm trying to do with this video is have you become familiar with these terms so that then when you hear them for the more complicated topics that you know exactly what we're talking about. So now first let's review the basic physiology. So as we know we have our alveoli here in black and the blood flows into the lungs from the pulmonary artery and the blue here represents the deoxygenated blood. And so then CO2 is diffused into the alveoli and then O2 oxygen coming in through the lungs and the alveoli gets diffused into the pulmonary vein and then is transported to all the cells throughout the body. And this is by the simple principle of diffusion like so many things in our body. So things move from an area of higher to a lower concentration. In this case the atmospheric pressure is higher than the introthoracic or intraabbiola pressure therefore everything will diffuse. And then so another important topic we're talking about respiratory is oxygenation. And the oxygen in the body can really be found in two different places or measured in two different places. So first of all it's dissolved in plasma which is expressed as millimeters of mercury in the partial pressure of oxygenation and then the other part is bound to the hemoglobin in comparison to the amount the hemoglobin can carry. So the amount of total hemoglobin available and then how much of that is saturated with oxygen modules that can then be expressed in percentage which is also our oxygen saturation of pulse oximetry that we'll get to in a little bit here. The other important term here to know is ventilation. So ventilation is the actual process of air moving in and out of the lungs and that has two parts inspiration and exhalation. And the change again happens because of the or the ventilation happens because of the change in the introthoracic pressure. And again the pressure in the atmosphere is higher than in the chest cavity and so oxygen will just diffuse in from a high to a low concentration. And the exhalation keep in mind is a passive process because of this elastic recoil of the lungs. So actually the inhalation is an agar more of an active process although we're not usually aware of the inhalation but then just by slowly recoiling the chest and all the accessory muscles and the costumus and the diaphragm being moving back in the original position it's called the elastic recoil, the elastic recoil ability of the chest wall. And then so over here the other terms are compliance and resistance and a lot of times you'll hear that when we talk about some critical care topics and we'll get into those here. So compliance first is the ease of lung expansion. So it's basically the ability of the lungs to inflate and deflate and that's the lung elasticity and again that chest wall recoil. Now when we have decreased compliance then it's difficult to inflate the lungs and there can be several causes that cause that. So the lungs are not easily expanded if there's fluid in the lungs such as in pneumonia, pulmonary edema or ARDS. If there's decreased elasticity of the lungs so when now the arveoli are not as pliable if you want to call it that and easily open and close such as in pulmonary fibrosis we have problems with decreased compliance or when there's decreased lung movement when now the lungs can't expand because there's fluid sitting in that pleural cavity due to a pleural effusion for example. So these are all causes for decreased compliance. But the compliance can also be increased and that would be the destruction of arveoli such as we see in patients with COPDO and Pizema where the arveoli are hyperextended and so now that lung, the arveoli is always kind of like hyperinflated and that would be increased compliance. And the other term here is resistance so resistance is when there is airflow difficulty during inspiration and expiration due to a change in airway diameter. So this is when we think about bronchoconstriction when for example in asthma patients all this inflammation makes the airways constricted and then causing a problem with resistance so then there's more resistance and more force needed to get the air into the lungs and that can cause some problems here because of that airway diameter. Just so you know the triangle here means change it's a very commonly used abbreviation in the medical field I know we don't see much handwriting anymore but it's a very easy way of saying change and it's just something that I've been using over the years and just so you know that that's what that means. Okay and then another term we need to look at is ventilation and perfusion and the abbreviation for it is VQ. Don't ask me who came up with that why it's not V and P for perfusion I don't know it's called VQ so V for ventilation and Q for perfusion. Normally we perfuse 4.5 liters per minute so that's the typical cardiac output that flows throughout the body and then through the lungs to get oxygenated and we strive for perfect balance as always for homeostasis and that usually means that each one milliliter of air through the ventilation so that inhalation and exhalation is each one milliliter of air is there for each milliliter of blood perfusion so that would be a perfect one to one VQ ratio right ventilation and perfusion one amount each and so that's a perfect system with a where everything works perfectly but there is a term called a VQ mismatch so now the ventilation and the perfusion are not matching so we either have not enough air or not enough blood it's usually the problem right we don't well we could have too much blood too in certain conditions but that's less likely and so when we have this VQ mismatch when there's ventilation causes that can be because of secretions so think of somebody who has a lot of thick secretions and mucus then the ventilation is not going to be so easy that airflow in and out of the lungs if there's bronchospasm so if the bronchial is kind of constricted on the expand that can cause problems with ventilation if there is alveolar collapse such as an electrolysis it can cause problems with ventilation because now these alveolar are not able to perform the oxygenation by the principle of diffusion over here and then also if there's pain right the there's pain the chest cavity patient tends to not want to take a very deep breath and so that can be a problem with ventilation and then perfusion causes so causes now that pertain to the blood flow so if we now have don't have enough blood flow come in here then the CO2 can't be diffused back into the alveoli and then we don't have enough blood volume or enough hemoglobin molecules for the O2 to attach to and causes can be pulmonary embolism so now if there's a clot somewhere over here in the pulmonary artery it's going to allow less blood to flow through or if we have anemia so if we have less blood volume to begin with then we're going to have problems with perfusion and all these so either ventilation or perfusion problems will indeed will lead to hypoxemia so low oxygen in the blood and the cure or the treatment is administer O2 and that can be as simple as an exocannula or non-rebreater mask remember that when we administer an esocannula or non-rebreater mask we can't really regulate the percentage of O2 that we're giving the patient so these causes are usually not as severe now then we have another term that we need to look at which is called shunting and that means the blood exits the heart without oxygenation so now some of the blood is being shunted somewhere where it kind of bypasses the alveoli right or the lungs in general and that can be due to an extreme VQ mismatch so now we have an extreme ventilation or perfusion problem and that can be either due to anatomic reasons such as in structural heart defects as in atrial septal defect or ventricular septal defect that we see in children and sometimes even in adults and then the other cause can be to intra pulmonary problems such as ARDS acute respiratory stress syndrome or pneumonia now in this this case when there's shunting involved that patient will also suffer from hypoxemia so low oxygen in the blood but just simple oxygen administration is not going to solve the problem because we have this extreme VQ mismatch so now this patient is going to need mechanical ventilation and then increase an increase in FiO2 and FiO2 stands for fraction of inspired oxygen and that is basically the percentage that would give the patient a percentage of oxygen to be administered and that can only be measured by a ventilator machine such as a ventilator and so these are very important terms to know oxygenation ventilation compliance resistant ventilation perfusion and shunting and so then how do we measure this so ABGs are going to be very important measures or blood tests to monitor which gives us an idea about the patient's oxygenation status and their acid based balance because we know that the respiratory and renal system work together to maintain pH balance and ABGs usually give us the pH the PACO2 the PAAO2 the saturated O2 and then the bicarbonate in exchange for the hydrogen ion on the acidic side and then for monitoring or nursing care there are basically two different ways we can monitor the patient's respiratory status which is simple as a pulse oximetry that will probably offer manual with that probe that we put on the patient's fingertip and remember that it's normal to be about 94 to 99 percent depending on what textbook you're looking at or what hospital you're working at but it's less accurate if the O2 set is less than 70 percent which means that it can differ by 4 percent so if the patient's oxygenation sows 70 percent it really could mean that it's 66 or 74 and that again has a big difference between 66 and 74 although both are pretty bad numbers and that here again measures the hemoglobin the amount of oxygen bound to the hemoglobin in comparison to the amount that the body that the hemoglobin can carry so that is that percentage that we talked about over here and then the other way we can measure the patient's respiratory status which is a little bit more accurate is CO2 monitoring so we can measure both your oxygen and CO2 in the body and first of all it can be transcutaneous which is usually done in the pediatric or NICU population which is basically an electrode displaced on the skin that detects the patient's CO2 level and there is also the end tidal CO2 and that basically means that at the end of the tidal volume of the total volume that the patient can inhale and exhale we're measuring the CO2 during the expiration and that is all possible through various different methods so that can be done through the endotracheal tube through a tracheostomy and even through a nasal cannula so you might have seen these nasal cannulas then have a little bubble attached to them and that little device is the device that picks up the CO2 that the patient is exhaling and is oftentimes used in sedation procedures such in the emergency department or maybe in the operating room or in the recovery room or you might also see it when the patient is on a PCA pump because then we worry about sedation which can influence their respiratory status and rate and so we want to monitor making sure that they are not hypoventilating which we could detect by changes in their expired CO2. So thanks for watching this video on the respiratory terms of physiology which serves as a baseline to look at the different respiratory disorders specifically the critical care ones and these are everything basically that we've listed here, pneumonia, pulmonary edema, ARDS, florafusion, COPD, asthma, there's all these conditions here that you'll find on another playlist where I explain those in more detail but again these terms are important to know. Thanks for watching Nursing School Explained please give me a thumbs up if you liked the video and I'll see you soon.