hey guys it's medical system fictionalist where medicine makes perfect sense helping medical students nursing students pharmacy students get their head out of their collective sphincters one student at a time we continue our anesthesiology playlist in the previous video we have learned how to manage the airway it's time today to talk about regional anesthesia so let's get started this is my anesthesiology playlist please watch these videos in order today is video number seven as we have discussed before anesthesia is not the same as analgesia you can say that analgesia is part of the anesthesia energy is a subset of anesthesia every time you have anesthesia like general anesthesia you will have analgesia with it but i can give you a pain medication pain medication will make you analgesic yeah no pain however you're still conscious oh yeah so just because i have analgesia doesn't necessarily mean that i have anesthesia let's start by answering the question of the previous video should i pre-medicate the patient in order to prevent aspiration the answer is unequivocally absolutely no no you do not because the overwhelming majority of patients are at very very very very low risk of aspiration syndrome anesthesia care phase there is preoperative there is intraoperative and there is postoperative and we have talked about that before anesthesia is general regional or local regional which is today's topic is neuraxial limb or others noraxial why neuro because we're talking about the nervous system here okay why axial because the spinal cord is in the axis is in the center the middle of your body it's in the median plane okay and then we divide the noraxial blocks into spinal and epidural the epidural is further subdivided into thoracic epidural lumbar epidural and caudal epidural in caudal you usually go through the sacral hiatus in this video we'll talk about spinal and epidural in the upcoming videos we'll talk about limb blocks in the good old days which were not so good regional anesthesia used to be called conduction anesthesia it's important to know whence we came so that we may understand where the flip we're going some person once said we do not live in the past but the past in us but medicosis says anatomy does not live in embryology but embryology lives in anatomy wow this was so deep honestly i have no idea what the flip this means let's review some embryology fertilization then cleavage then blastulation then implantation by laminar embryo tri-laminar embryo what is bilaminar epiblast hypoblast what is tri-laminar endoderm mesoderm ectoderm the ectoderm in the third week will give you your nervous system under the influence of what of the primitive streak as you know you have four types of tissue nerve tissue comes from the ectoderm your lovely nervous system with either cns or pns central peripheral central brain and spinal cord peripheral cranial nerves spinal nerves the spinal cord has many segments cervical thoracic lumbar sacral and coccygeal your beautiful ectoderm will give you surface extra for the epidermis of your skin and neuroectoderm four central nervous system neural tube and peripheral nervous system neural crest if you want to learn more about this check out my video titled neuralation in my biology playlist all right ectodermy you gave me the brain the spinal cord as well as cranial nerve spinal nerves all right how about mesodermal notochord the notochord will give you the nucleus pulposus of the intervertebral disc so here is a vertebra here is another vertebra a third vertebra between them you have one between a vertebra and the next vertebrae have an intervertebral disc the intervertebral disc is made of two parts the outer part called annulus fibrosus and the inner part called the nucleus pulposus if this is anterior and this is posterior you see that the spinal cord is behind the vertebral bodies here's your epidermis of the skin and here is your neural tube and neural crest neural tube will become brain and spinal cord neural crests will become cranial nerves and spinal nerves got some segmentation action going and look at this look at this beauty very beautiful neural tube that's your spinal cord here and then you have the neural crest became the spinal nerves what's the name of this beautiful canal in the middle spinel canal how about the vertebral canal no no the vertebral canal is a bony canal and this surrounds everything here so the spinal cord itself with its roots lie inside the vertebral canal however if i cut the spinal cord transversely inside the spinal cord itself there is the spinal canal which contains cerebrospinal fluid that's the spinal cord we can do the same thing for the brain in this case the neural tube will be the brain itself the neural crest will be cranial nerves and the cavity inside the brain is the ventricles containing csf see medicine makes so much sense once you understand what the flip you're talking about so here's your brain prosencephalon mesencephalon and rhombencephalon let's look at the inside at the inside you have a cerebrospinal fluid inside these cavities called ventricles it's made here in the lateral ventricles who makes the cerebral spinal fluid okay ready ependymal cells of the choroid plexus which lines the ventricles okay cerebral spinal fluid is here lateral ventricles and then we'll go from the lateral ventricles into the third ventricles how did you go from here to here through the interventricular foramina of monroe next we are here in the third ventricle nice let's go to the fourth ventricle how do you go through the city bra aqueduct of silvius the same doofus who discovered the sylvian fissure but that's a story for another time and then after the fourth ventricle where would you go all right i have a median opening and i have two lateral openings median in the midline what's that this is the foramen of magente and then you have two lateral foramen of lushka so lateral is lushka but median is mizandi nice and then where will the csf go the csf will go all around your brain nice where where is it here it's in the subarachnoid space all right and all around your spinal cord where is it here in the subarachnoid space also it's in your brain called ventricles and inside your spinal cord called spinal canal here is the spinal cord as you see posterior horn lateral horn interior horn of the gray matter okay literal will give you autonomic fibers if you are thoracolumbar this is sympathetic if you are sacral this is parasympathetic all right in epidural or spinal anesthesia where the flip do we dip the needle you stick the needle into okay listen to this song to keep the spinal cord alive keep the needle between l3 and 5 so between l3 and l5 we are in the lumbar area yes do you think lumbar has sympathetic or parasympathetic fibers of course it has sympathetic okay and don't forget that sympathetic preganglionic were type b fibers by the postganglionic type c fibers oh yeah type c is the thinnest type b is the second thinnest which means they get affected by the anesthetic before others and that's why one of the side effects of epidural or spinal anesthesia is hypotension why because you will affect the sympathetic earlier and then what when you affect the sympathetic you cannot constrict your arteries because you have lost alpha-1 stimulation you also cannot constrict your veins oh so this will decrease the venous return oh and this will decrease the cardiac output oh yeah because if there is less input to the heart there will be less output from the heart well no duh so hypotension is a common complication of neuraxial block the meninges you have the duramata arachnoid mata and pia mata by the way it's mata not matter matter is just a substance but mata is mother so if your biological mother has abandoned you in order to go get a pedicure just remember that you have three mothers hugging you 24 7. the dura mata arachnoid mata and the most loving tender pia mata where the flip is the cerebral spinal fluid oh it is in the subarachnoid space where the flip is that between the arachnoid and the pia jura is the outermost pia is the innermost between the arachnoid and the pier you have the cerebrospinal fluid where is epidural anesthesia here outside of the juror where is the spinal anesthesia here in the sub-arytenoid space between the arachnoid and the pia by the way the arachnoid mata is a pharmacological barrier so the epidural anesthetic will not reach the subarachnoid space unless of course you are a doofus and you have penetrated the dura and the arachnoid by mistake oh wow look at that this is so beautiful frank netter is getting jealous here is the back of the patient and let's go first layer skin then subcutaneous tissue go deeper supraspinous ligament and then enter spinous ligament and then don't say infraspinous because you look a stupid it's called ligamentum flavum of vertebra and then epidural space oh epidural is above the dura no kidding after the jury you have what subdural and then arachnoid mata and then the subarachnoid space which has the cerebrospinal fluid pia mata the pier is hugging the spinal cord and then you continue pier subarachnoid arachnoid subdural and jewel because they are certain it's like a circle it's a circle baby and then you will hit the posterior longitudinal ligament and then you have vertebra see here's the vertebral body body body between them you have the intervertebral disc the green part is the outer annulus fibrosis the gray central part is the nucleus pulposus and then after that anteriorly you have the anterior longitudinal ligament i want to leave a legacy to this world i do not want anyone to remember grey's anatomy maybe as an afterthought now let's get a lovely needle and inject a local anesthetic into the epidural space aka epidural anesthesia look at this look at this look wow i'm in the epidural space so i've pierced the skin subconscious tissue supraspinous interspinous ligamentum flavor and now i'm in the epidural now let's perform a spinal anesthesia wow wow oh look at that look wow we are in the subarachnoid space which has cerebral spinal fluid it's easy to detect this because you can just let the needle drip and it will drip some cerebral spinal fluid however this is the reaper spinal fluid and not the sailing that was in the freaking needle easy the saline that you injected was at room temperature ah but the solubility sponsor is going to be warmer because the patient's body temperature is warmer than the room temperature you freaking doofus so let these drops drop onto your forearm and feel them if they are cold that's your saline if they are warm that's the patient cerebral spinal fluid congratulations you have entered the promised land spinal is in the subarachnoid epidural is in the epidural socrates said that the best way to learn is asking questions all right q a let's go is the patient conscious during the neuraxial block the answer is yes move the time can i sedate like ed benzo's opiate yeah you can some in many cases you can put the patient to sleep do i need to add a neural muscular blocker such as v uronium absolutely not because it is included in the package it's part of the deal it's part of your injection when you inject the local anesthetic it will paralyze the patient's muscle because you are around the spinal cord you absolute dork what comes out of the spinal cord um motor fibers yep you will block them can neuraxial nerve block cause permanent nerve injury it's possible but it's very unlikely be careful because many patients will exaggerate this and here is how it goes down hey karen how are you welcome to the clinic hi doctor how are you you won't believe what happened to me the bastard who is the bastard the anesthesiologist doctor he paralyzed me now i'm paralyzed from the waist downwards then how come you are wiggling your toes karen well i'm not paralyzed in the toes i'm only paralyzed in the thigh and the legs but my feet are fine this is anatomically impossible karen because the lumbosacral plexus starts in the spinal cord and then it goes downwards so if your feet are fine it means that everything before your feet is also fine so you're saying that i am lying i'm not saying anything anatomy is what anatomy does i don't have the luxury of creating the universe on day one how dare you so the permanent nerve damage can happen but it's extremely unlikely what's the first ligament to be pierced by your freaking needle the supraspinous ligament what happens if my epidural needle hit the artery of adam kiewicz oh my goodness the patient can suffer from anterior spinal artery syndrome pain and temperature sensation they're gone crude touch sensation gone motor functions gone how about the fine touch vibration and proprioception they are preserved because these are in the posterior and not the anterior part of the spinal cord if you remember your neuroanatomy do you remember the phenomenon of time synergism yup adding the local anesthetic and epinephrine together all right why do you add epinephrine to the local anesthetic for many reasons because it's a vasoconstrictor it decreases the release of substance b so it decreases pain also when your vasoconstrict you decrease the absorption of the local anesthetic the local acid is going to stay in place and this will keep it localized and it increases the duration of the action of local anesthetic also when you constrict the vessel less local anesthetic will escape through the systemic circulation which means less systemic toxicity and less bleeding from the procedure because of the vasoconstriction so can i add epinephrine to my local anesthetic during neuroaxial block yes you can what if my patient has any condition that increases their intra-abdominal pressure example abdominal mass abdominal tumor ascites etc what's going to happen any of these conditions will press on the inferior vena cava in the abdomen okay any vein that wants to drain into the inferior vena cava can kiss my calcaneus it's not going to happen because the vein is congested oh so congestion here will lead to congestion here what the flu is that that's your internal vertebral venous flexors oh so while your needle is trying to go into the patient's back the needle is more likely to hit a vessel because the vessels are congested why didn't your freaking anatomy professor tell you these stories because he's woke medicine makes so much sense if explained properly anatomy is boring but clinically oriented anatomy is the best thing since sliced bread what kind of local anesthetic solution should i inject into the patient's epidural space or subarachnoid space you have three options a hyperbaric isobaric or a hypobaric solution what's the difference hyperbaric we are we mean it's not the pressure it's the density and in physics density is mass over volume if you remember so hyperbaric is literally heavier than the csf and isobaric is like the same density as the csf hyperbaric is lower density which one is the most commonly used hyperbaric although it depends on the surgery and the position of the patient the rule of thumb is that you want the anesthetic to be away from the surgeon so let's say that this is a perineal surgery so here's the patient's feet all right nice nice nice nice and the patient is in the jackknife position because it's a perennial surge the surgeon is working here all right in this area where do you want the anesthetic to be away from the surgeon i want the anesthetic to be floating on the surface of the patient's back here inside not deep because it's closer to the surgery i want to be away from the surgery so in this situation you may consider a hyperbaric solution because it's going to float your thoracic spinous processes look like this they are pointing downwards however if you go to the lumbar area they are pointing outwards like this and that's why the midline approach is usually the most used but in this case you might try para median which means you go lateral and you go downwards in order to be able to hit the space surface anatomy very important now get your beautiful head and touch your hair and go down down down down down down your neck until you reach something that's very prominent yeah a prominent bone this is c7 baby in the midline of course and then you go down okay the lower edge or the lower border of the scapula is t7 nice how about the last rib l1 nice how about the iliac crest l4 how about the posterior superior lex spine this is s2 where should i put the needle to keep the spinal cord alive keep the needle between l3 and 5 because before l3 most people have their spinal cord ending about l1 to l2 level so you're going to be below this there is a difference between the spinal segment here inside the spinal cord vertebral body which is a bone and the dermatome which is skin segment all right spinal segment for example look at this look at the c1 all right c1 goes above c1 bony vertebra nice how about c2 above c2 vertebra how about c3 nerve above c3 nerve vertebra but since you have eight nerve segments here but only seven vertebral bodies oh where do you think c8 is going to go below c7 which means above t1 therefore the t1 nerve is below the t1 vertebral body t2 nerve is below t2n then etc etc etc so the vertebral body and the small segment are not always the same moreover as you go down the nerve start to go down and the exit go down before the exit go down before the exit so the l4 skin dermatome might be here however the l4 spinal segment is up there so they are not at the same level as a general rule the level of the sympathetic block is more cephalic which means upward than the level of the sensory block which is more cephalic than the level of the motor block spinal versus epidural anesthesia let's go indications when should i use spinal if the surgery is in the lower abdomen pelvis pernium lower limbs do not use it if it's upper abdominal or thoracic surgery you might go with general anesthetic and not spinal anesthesia all right epidural same thing surgery in the lower abdomen pelvis perineum lower limbs also it's used in combination with general anesthesia you can use general and epidural together during labor and delivery continuous epidural for pain management postoperatively doctor the surgery is gone but i have severe pain you can give epidural to manage the pain contraindications of course if the patient refuses the procedure you don't do it bleeding diathesis this is not an absolute contraindication there is guidelines and it's complicated infection in the area that you'll inject into intracranial hypertension because if i have intracranial hypertension you should be removing some of my csf not adding more to my csf you freaking doofus paresthesia upper etc and the same things here if the patient started complaining of paresthesia while you're injecting the local anesthetic you stop you stop the procedure immediately because paresthesia means you have hit a freaking nerve which position should i put the patient in there is lateral decubitus there is sitting there is prone the jackknife position is used for pernil surgery epidural same positions patience positioning is more relevant here for spinal not so relevant in epidural where should i stick the needle to keep the spinal cord alive keep the needle between l3 and 5. if it's codal epidural you will go through the sacral hiatus what are we injecting local anesthetic not general local so pharmacologically speaking you have a general anesthetic and a local anesthetic there is no such thing as a regional anesthetic agent we're injecting a local here where are you injecting it subarachnoid space epidural space spinal takes less time here the procedure takes more time the patient will experience less discomfort with spinal more discomfort with epidural you know why because it takes more time no duh this needs less anesthetic this needs more and that's why you need to be very careful and not to pierce the dura because if you pierce the dura mater and you're injecting tons of local anesthetic you can cause permanent neurological damage you freaking doofus sensory and motor blocks has a stronger block of course because you're deeper which one is easier here just keep pushing until csf comes out of the needle any doofus can do it but epidural it requires a pro segmental block can be achieved with epidural you can fine tune the epidural yeah because when you change the concentration this will easily change the intensity of the block easily is the key word here do you need titration spinal ah probably not epidural yup long-term administration is easier with epidural which one depends on the natural normal curvature of your spine spinal of course spinal with spine of course the normal curvature is normally have some lumbar lordosis but sacral kyphosis thoracic kyphosis cervical lordosis complications the risk of post dural punctural headache is higher with spinal lower with epidural the risk of hypotension is higher because you're deeper of course complications of neuraxyl block what are the complications of spinal anesthesia one through ten hypotension which makes co might cause shivering why hypotension because you block the sympathetic you blocked the constriction and the venous constriction which will decrease venous return and cardiac output hypoventilation back ache bradycardia to the point of asystole because when you block the sympathetic the parasympathetic will be unopposed you might consider giving atropine here post dural puncture headache we'll talk about that soon you're in retention because you blocked my sensory fibers i cannot feel my bladder distending remember the micturition reflex nausea vomiting itching neurological complications and total spinal anesthesia what are the complications of epidural anesthesia 1 through 10 plus you might puncture the juror like a doofus and this is going to be dangerous because you are using lots of local anesthetic if you inject this to the subarachnoid space instead of the epidural space you can cause permanent neurological damage don't do it epidural abscess epidural hematoma nerve injury or permanent neurological damage post dural puncture headache more common in younger patients than older ones the larger the needle the greater the risk of headache why does the headache happen because you punctured a hole in the dura which will cause loss of some acidity but your spinal fluid which will lead your brain to sink in place your brain will be displaced downwards causing headache if the brain sinks too much it might tear some of the bridging veins which can lead to subdural hematoma when does the headache happen about 14 to 18 hours after you pierce the dura mata the headache is usually frontal or occipital or both you can also find ocular disturbances most commonly diplopia especially due to the abducens nerve injury because this is the one affected whenever you have any problems with the brain sinking change in pressure cranial nerve 6 gets hit like crazy photophobia and seeing spots in front of me treatment conservative management bed rest fluids pain medications and then you give the patients caffeine so should i run to starbucks and give him a nine dollar cup of nitro cold brew oh shut up i'm talking about intravenous caffeine injection run to starbucks oh give me a break do you want some mocha drizzle with that too get your head out of your sphincter and the last is blood patch what the flip is that you take some of the patient's blood and you inject it into the patient's hebrew spinal fluid can i give him some of my own blood because i love my patients so much shut up you can trigger an immunological reaction question of the day who is prone to aspiration syndrome coming up next limb blocks if you like this video you will love my acid-base disturbances course it's the best course that i've ever created comes with 30 videos 25 cases notes per fictionalist ultimate notebook and mind map available at medicosisperfectionalis.com thank you so much for watching please subscribe hit the bell and click on the join button you can support me here or here go to my website to download my premium courses thank you for watching as always be safe stay happy study hard this is miracles perfectionist worms and makes perfect sense