hi there this is nasul and i'll be presenting bowel obstruction which is a lower gastrointestinal disorder during this lecture we'll be looking at the classification of bowel obstruction and there are two classifications mechanical bowel obstruction and a non-mechanical which can also be referred to as a functional bowel obstruction when we're presenting or looking at these two types of bowel obstruction we'll look at it from the ethiological risk factors the pathophysiology that's involved and a clinical manifestation how they differ between these two types of bowel obstruction so before we get into the actual content of bowel obstruction or intestinal instruction i think it's important that we look at how does food propel or travel through the gi tract so once food is consumed and it's broken down by gastric juices and other intestinal juices and chemicals as we try to break down food in their smallest component to obtain nutrients from it the food is then made into a bolus and that bolus has to get through the gi tract one process by which food gets through the gi tract is by peristalsis and really what peristalsis involved is the longitudinal circular and diagonal muscles that is in the gi tract will contract and this is where you're seeing the contraction right here and that contraction allows for a kind of sequential or a wave like motion that will then push the food forward through the gi trend there's also a different process involved at the same time called segmentation and segmentation mostly involves longitudinal and circular muscles in the small intestine where they kind of squeeze food back and forth along the intestinal wall all in an attempt to move move food along and also allow for nutrients and chemicals to be absorbed from the small intestine so that brings us now to discussing what is an intestinal obstruction without making classification that is whether it's mechanical and or non-mechanical just as a broad discussion intestinal instruc obstruction really involves either a partial or a complete obstruction in the intestine that prevents contents or intestinal contents from getting through the gi tract most often where it occurs is in the small intestine but being mindful that bowel obstruction can also occur in the large intestine obviously because of the narrowing of the tube that we often would see obstructions happening mostly in this small intestine so it's not uncommon to see diagnoses of sbo which is really small bowel obstructions so when we look at bowel obstruction as a broad category that bowel obstruction can then be split are classified into a mechanical obstruction and or a non-mechanical or functional obstruction bowel obstructions are classified based on the cause so mechanical obstruction the causes are different from those of non-mechanical or functional obstruction when we look at mechanical obstruction there is physically something that is obstructing or causing an occlusion so an obstruction and or an occlusion in the lumen of the gi tract therefore once there is something physically there in the lumen it does not allow contents of the gi tract to get through whereas with a non-mechanical or functional obstruction there is no physical obstruction or physical occlusion within the lumen of the gi tract but rather what is happening with the non-mechanical or functional obstruction there is a loss of peristalsis and remember earlier we talked about the importance of peristalsis and segmentation in moving contents forward within the gi tract so loss of peristalsis therefore means that there's going to be stasis of the gastrointestinal content trying to get through the gi tract leading to an obstruction within the gastrointestinal tract so looking at bowel obstruction when we look at the two classification which is mechanical obstructions and non-mechanical or functional bowel obstruction the reason that these are categorized categorized and or classified this way is based on the cause so the causes of mechanical obstruction would look differently than that of functional obstruction now with functional obstruction or non-mechanical the most common type is referred to as paralytic alias when you see the word alias ilius simply means gut so when we use the word alias this means that gut and therefore what this simply means that a paralyzed gut now you'll also see that there's an alternative term that can be used instead of paralytic which is we could refer to it as a dynamic alias pretty much have the same meaning where that gut or the alias is lacking peristalsis resulting in a bowel obstruction so causes of mechanical obstruction includes tumors adhesions hernias vulvulis or a telescoping of the bowel and this will all be discussed on the next slide so something is physically present that is causing the obstruction or occlusion within the gi tract so it could be a tumor that's present there it could be an adhesion that's there or the patient has a hernia and or a volvulus or the bowel is telescoping itself that is causing that physical obstruction to occur now remember with an a dynamic alias or non-mechanical there is no physical obstruction within the gi tract but rather there's a loss of peristalsis not allowing for the contents to move through so when you think about what causes a bowel to become paralytic or to become a dynamic think about inflammation and the release of chemical mediators that can potentially during that inflammatory process stop or put a halt to peristalsis so things like pancreatitis peritonitis any sort of infection within the abdominal cavity hypokalemia can do it post surgery as a result of anesthesia etc there's medications that can also cause this to occur so there's many examples of things that can result in a functional bowel obstruction but again just to recap the classification whether a patient has a mechanical bowel obstruction versus a functional or non-mechanical is primarily dependent upon the cause so looking at the causes of mechanical obstruction i farsaf would like to say these images were adopted or taken from medical surgical nursing in canada fourth edition by lewis at all and so when we look at the causes one of the first one we look at is a which is adhesion so this a diagram is looking at an adhesion and so when you ask yourself what is an adhesion an adhesion really is a band of scar tissue that is kind of attaching or banding [Music] two loops of bowel together so a band of scar tissue [Music] holding together two loops of vowels and so if whole together the loops of bowel what that means is contents cannot get through the gi tract so as content is trying to make its way through the gi tract there is a physical obstruction at the point of where the adhesion is b which is looking right over here this is a hernia and so this is a male patient and often what it is really a hernia is where the intestine pretty much gets through the inguinal canal and it's kind of stuck there again causing an obstruction because as the content of the gi tract is trying to get through then it's blocked or it's kind of cut off where it's trapped in that inguinal canal now women can also have hernias often it's abdominal hernia and usually after a pregnancy where the abdominal muscle becomes weak or if you've had multiple abdominal surgeries where again the abdominal muscles become weak the gut can then kind of slip through within the muscle and get trapped again resulting in what we refer to as an abdominal hernia c is looking at and that's right over here this is called intussusception or what's often referred to as telescoping of the bowel so in the previous slide we talked about telescoping of the bowel and what it really means is one portion of the bowel slips into or kind of folds itself just exactly how a telescope slides into itself but if you think about it now the content of the gi tract is trying to get through [Music] it's hitting a physical obstruction because of the telescoping intussusception or telescoping of the vowel is very very common in children more so than your adult patients so babies are often subjected to telescoping of the bowels and so their presentation how they present clinically is they would come in with projectile vomiting they're crying they're inconsolable often the legs are pulled up and they're just in excruciating pain so intussusception is also referred to as telescoping f is showing you what a neoplasm is so a neoplasm or a tumor will then also cause an obstruction or an occlusion within the lumen of that gi tract not allowing content to get through and then lastly g this is called a volvulous and now the reason are the cause for evolvius is often idiopathic so they're not exactly sure what causes a volvulus to occur and really what a volvulus is it's the twisting of the gut where the gut kind of like banned itself in a knot for idiopathic reasons but again as the content is trying to get through to the gi tract once that knot is there then you can put the content through again leading to a mechanical bowel obstruction so in our previous slides we looked at the causes for mechanical obstruction now looking at the second classification for bowel obstruction non-mechanical or functional obstruction remember in the previous slides we mentioned that it involves the loss of peristalsis so things that might cause a loss of peristalsis is some sort of neuromuscular or vascular disorder and with non-mechanical or functional obstruction there is a halt in peristalsis where it's non-existent and therefore the contents within the gi tract cannot move forward there is no physical obstruction within functional obstruction it just means that the alias or the gut becomes paralyzed or a dynamic and the most common type of non-mechanical or functional obstruction is something referred to as paralytic alias so there are many causes to functional obstruction and one of those things um is post-op so often this is referred to as post-operative alias where you'll see a decline or an arrest in intestinal motility post operation there are many risk factors that can cause this so some of the things that can result in a patient ending up with functional obstruction post-op could be age could be a big reason in why they're at risk electrical imbalances electrolytes imbalances so when we look at some of the electrolytes that can become imbalanced during surgery potassium sodium those are all things calcium as well can also become abnormal surgical factors so start to think about medications that are used so opioid medications attaching to moon copper receptors in the intestine slowing down intestinal motility also we could have some contamination in the process when they're doing abdominal surgery could occur so there's a number of reasons why initial stages of a spinal cord injury with spinal cord injury it always remember that within the gi tract we do have the nervous system so often referred to as the enteric nervous system that innervates the gi tract and so what it does is it get receives the signal and that's how it's communicated to cause the release of gastrointestinal juices etc so in that initial stage of your spinal cord injury that message from the entire nervous system becomes lost and therefore what we are going to see is a halt in peristalsis to try to squeeze or have that sequential movement to move things along pancreatitis peritonitis or an infection in the abdominal cavity all are causing a release of many chemical mediators that can cause cessation or a halt in intestinal motility hypokalemia a very very important electrolyte that helps with contraction of muscles and so if there is hypokalemia and don't lose sight of your hypocalcemia so a drop also in calcium ions then that could also result in a decrease in intestinal motility and in burns burns is a big one where we see fluid shifting in burns often fluid shifts out of the intravascular compartment into interstitial and third space reducing that intravascular volume which means that we're going to see hypoperfusion remember the gut when your patient is hypovolemic or they have a low blood pressure the gut is not really considered an essential organ so once that fluid shifting is occur you're going to see hypo perfusion to the gut and so because of the hypoperfusion to the gut enough blood supply oxygen and nutrients is not getting into the gut and therefore that could result in an a dynamic ileus because we're losing that peristalsis to move the contents along so in this slide we're going to look at the pathophysiology of an intestinal obstruction so when we look at the intestinal obstruction this could be as a result of a mechanical and or a non-mechanical obstruction but often it's just easy to look at the mechanical obstruction because we know there's something physically there so in this case we're going to kind of insert an obstruction point right here and we're going to say that's our point of obstruction so it could be a tumor it could be an adhesion a volvulus intesception are something that's causing the obstruction to occur now this patient has just consumed food and so that bolus of food is making its way down and then it hits the point of the obstruction now remember we talked about the enteric nervous system that not only promotes the peristalsis or allow for peristalsis to occur but it's also going to encourage gastric juices all those things to be released to try to break down this bolus of food but once the food has hit that obstruction point what you're now going to see with your patient with an intestinal obstruction there's going to be an accumulation of gases and so that those that gas that is being accumulated there could be as a result of the patient swallowing air just from talking and all those activities or it could be from um intestinal bacterial metabolism that's occurring so we're going to see accumulation of gases gastric juices and this is all accumulating in the area proximal to the blockage so just where the area of blockage is just proximal we're going to see the accumulation of this gas so what does this mean for the patient so if we were to look at the intestinal area we're going to say this is where the tumor is and that bolus of food is just behind here trying to make its way through but now what's starting to occur is we're going to see fluid so this is our fluid is accumulating here air is accumulating and that's all trying all accumulating in the area that's proximal to the obstruction what that's going to then result is what you're going to see physically in the patient as abdominal distension so it's not uncommon that one of the clinical manifestations of an abdominal intestinal obstruction to be abdominal distension now as that fluid and gases are accumulating in this area this is further sending a signal to or via the enteric nervous system to say come on make stronger contractions in the intestine in an attempt to try to move the intestinal contents along so what you're now going to see is strong contractions so remember we're referring here to a mechanical obstruction so we're going to see strong contractions of the proximal intestine and those contractions are again occurring because it's trying to push the content along so if we kind of draw the gut again what we're going to see is if that bolus of food is right here that we're trying to move along but remember we do have our obstruction right here where i'm going to see strong contractions is occurring right proximal to this area trying to move that bolus of food along unfortunately because we have an obstruction there even though we're seeing the strong contractions there the food cannot be pushed along any further so because of that gas the increase in fluid what we're now going to see is increase pressure in the intestinal lumen so inside of the intestine we're going to see increase in the pressure and so we wonder what is the implication for that increase in pressure and one of the um the implication is we're going to see increase in intestinal secretions so now we have more fluid accumulating in the area proximal to that blockage and the more we have intestinal secretions accumulating there we're going to start to see the veins within the intestinal wall is going to start to compress so this is going to lead to compression of the intestinal veins and as the intestinal veins are compressing what we're now going to see is fluid shifting is going to occur so this will cause not only the veins but also blood supply to the intestinal wall is being compressed and what this is going to lead to is fluid shifting into the peritoneal cavity and this is going to further cause and also into the walls of the intestine leading to edema of the intestinal wall so because of this fluid shift and i also don't want to lose sight is once you have that increase in the pressure and lumen the obstruction the increase in the intestinal secretion all of this is now going to also lead to vomiting so remember the gi tract has two opening the mouth and the anus so if we have an obstruction where you've seen our point of obstruction here if the content cannot go through the gi tract and out through the rectum then that's going to back its way up so now it's going to back its way up all the way out and what we're going to see is emesis in the patient okay or vomiting so that's also so abdominal distension i'm going to kind of put these um circle them in purple so an abdominal distention is one of the manifestations so our manifestations are going to be um in these little purple boxes that we're going to see these are going to be our clinical manifestation that we're seeing in the patient with the bowel obstruction vomiting also not uncommon to see in patients with a bowel obstruction so once there is edema um because of the persistent vomiting that we're seeing the fluid shifting and the edema within the intestinal wall what these things are then resulting in overall they're resulting in hypovolemia in your patients this is all going to result in hypovolemia in the patient or loss of intravascular volume now because we're losing that intravascular volume this is then going to lead to hypoperfusion of the intestinal tract so now we have less blood going to the intestinal tract so this is going to lead to hypoperfusion of the gut and as there is going to be less blood going to the gut makes sense this is now going to result in ischemia and potentially necrosis of the gut so now the gut is losing blood supply the arterial blood supply has been diminished and that's now going to lead to necrosis or ishikemia within the intestinal tract as the gut become ischemic and necrotic it means that we're now going to see cessation of peristalsis so if you start to think now this is almost kind of heading into the gut becoming a dynamic or the gut is now presenting like a functional obstruction and as that starts to occur where we're now going to see is that necrosis in the gut can end with the decreased peristalsis is now going to cause perforation of the bowel so this can then lead to perforation of the gut and so a perforation simply means is a hole in the gut and this can cause contents within the gi tract such as intestinal bacteria endotoxins all that stuff to leak into the peritoneal cavity resulting in what's called peritonitis now i don't want you to walk away thinking that peritonitis will always always occur in a patient that has a bowel obstruction now peritonitis is a complication of someone that is experiencing a bowel obstruction so that's like late stage one other thing that i want to point out with a mechanical bowel obstruction that could be a clinical manifestation is in the area when we see a strong construct contraction of the intestinal wall to try the movement to move the content along what this will be hard as when you auscultate the abdomen is you're going to hear hyperactive vowel sounds so this will result in hyperactive vowel sounds in the gi tract okay and again this is another clinical manifestation so in early bowel obstruction we're going to hear hyperactive bowel cells proximal to where the blockage is abdominal distension is common vomiting is common now if the gut becomes perforated and or the patient end up with peritonitis at that stage of the game that will lead to absent vowel sound so absent vowel sounds will occur in the later stages of a mechanical vowel obstruction so what this really captures is the pathophysiology that's involved in a mechanical bowel obstruction just kind of giving you the idea of how the disease process is going to be manifested so just looking back at the um this diagram i just thought it was interesting to look at it from the perspective of how fluid and ear is accumulated in the proximal aspect from where the obstruction is so this is showing you kind of what i drew before but now this is kind of showing you where that obstruction is and then the fluid that accumulates and then air that accumulates all of which is going to lead to proximal bowel dilatation causing abdominal distension in the patient so completing a quick comparing contrast between mechanical and non-mechanical or functional obstruction the very first thing is looking at the cause with mechanical obstruction there is a mechanical obstruction or a physical obstruction that is preventing contents of the gi tract to flow through the lumen and if we quickly try to recall what are some of the things that do cause in mechanical obstruction it's things like tumors volvulus which is a twisting of a bowel intussusception which is the same as telescoping of the bowel hernias etc whereas in non-mechanical or functional obstruction with the most common type being paralytic alias there is no mechanical obstruction within the lumen but rather there's a loss of peristalsis or where we have cessation of peristalsis and that could occur for a number of reasons so things like pancreatitis peritonitis hypokalemia or any other electrolyte imbalance even such as hypocalcemia can result in the loss of peristalsis also looking at the type of discomfort the patient will endure once they have a mechanical bowel obstruction it's more of a colicky pain and if you try to think back at why it is colicky that has to do with the increase in peristalsis proximal to where the obstruction is whereas in non-mechanical or functional obstruction because of the loss of peristalsis the patient is going to experience more of a constant steady discomfort hyperactive vowel sounds so in the early stage mechanical obstruction there's hyperactive bowel sounds and where exactly is that hyperactive bowel sounds and if you recall it's located in the area proximal to where the obstruction is and the reason why it's located there is because it's trying to move along that obstruction true to the gi tract and trying to move things along now remember in and this is early mechanical obstruction as the mechanical obstruction progresses there is a chance if it is not treated there is a chance that we can have necrosis ischemia and necrosis to the gut which will then cause that gut to perforate pretty much putting the patient into a functional or a dynamic alias with the non-mechanical or functional bowel obstruction there is decrease and or absent vowel sounds because there is no peristalsis and nothing is moving through the gi tract so looking at the treatment that is involved for intestinal obstruction the primary treatment is first inserting an ng tube or a nasogastric tube and the reason for inserting that is for bowel decompression and when we mean by bowel decompression is we want to remove so if you recall once there is an obstruction there is going to be excess gas and gastric juices and other sort of gi secretions that is accumulating proximal to where the obstruction is so by inserting an ng tube and attaching that ng tube to low intermittent suctioning we're able to remove that excess gas and secretion to this decrease bowel distension in the client and also to decrease the risk of vomiting because you know there is a high risk of vomiting and once the patients vomit along with the fluid shifting in the gi tract they're at risk for hypovolemia so one of the primary treatment when you have a patient with an intestinal obstruction is the insertion of an ng2 now surgery is also a second option so if there is no resolution with an ng tube insertion then the patient will be taken for a surgery this is just to give you a recall of the amount of fluid and or air that end up accumulating proximal to that obstruction and can cause abdominal distension and increasing pain nausea and vomiting in a patient with a bowel obstruction here again this is kind of just showing you and this was taken from the jama network and this just again shows you that when someone has a small bowel obstruction then it's normal to in to insert an ng tube and mostly what it is is to remove the fluid from the stomach or from the gi tract so that we're decompressing the bowel and again try to help to reduce the dilatation that is happening in the small bowel also very important which is often covered in theory is during your endotube insertion the patient will always always have iv fluid replacement for the nasal gastric content that is being removed or drained per shift now just for simple practice purposes two questions were included to help sort of solidify the content and the first question is which of the following most likely result in a mechanical obstruction select all that applies adhesions pancreatitis occlusion to a mesenteric artery a volvulus peritonitis and hernia so if you recall back from the beginning of the earlier slides of things that can cause so the key words in this question is mechanical obstruction so something is physically obstructing the lumen of the abdomen so if adhesions yes because they are a band of scar tissue that attaches two loops of vowels together preventing the flow of content through the bowel pancreatitis inflammation of the pancreas wouldn't result in a mechanical obstruction but rather a functional and or a non-mechanical obstruction occlusion of a mesenteric artery so the mesenteric artery supplies the gi tract or the gut with oxygenated blood if there is an occlusion at the mesenteric artery that's going to prevent oxygenating blood to get to the gi tract which can subsequently lead to ischemia necrosis of the gut and ultimately a functional or non-mechanical obstruction of the abdomen so c is not an option volvulus which is a twisting of the bowel is allowing for a mechanical obstruction to occur peritonitis again inflammation within the peritoneal cavity will result in a non-mechanical obstruction or a functional obstruction and lastly hernia where the bowels are trapped either in the inguinal canal or the abdominal muscle will definitely lead to a mechanical obstruction so when it says select all that applies your answers would include a d and f which of the following is a characteristic sign of mechanical obstruction abdominal distension colicky abdominal pain steady diffuse abdominal pain and absent bowel sounds and so when you're looking for the key words in the stem so which of the following is a characteristic sign of mechanical obstruction abdominal distension while we could potentially have abdominal distension with any bowel obstruction so regardless if it is a functional and or a mechanical obstruction so a would not be the best choice in this matter steady diffuse abdominal pain is mostly seen with functional and or non-mechanical intestinal obstruction and bowel sounds being absent again is seen with a functional obstruction colicky abdominal pain is most characteristic of a mechanical obstruction so in this case your answer will be b as in bob