General Anesthesia Part 1

have dippity this is dr. Marjorie from team MDS confer so in this video I'm going to discuss about the classification of general anesthesia and human cotton the general features of that inheres tell anesthetics so if you see this term anesthesia this means irreversible loss of response to a noxious stimuli and there are of two types of anesthesia as all of us know that local anesthesia which is regularly used in our dental clinics which in which their consciousness is maintained but you take the general anesthesia here we'll see their loss of consciousness there is a term called as balanced anesthesia so to call it as a balanced anesthesia there are four things to be happen that is unconsciousness analgesia muscle relaxation and abolition of compensated reflex responses so if this four things are present then it is called as a balanced anesthesia if you take the classification of anesthesia general anesthetics this is of two types where is inhalational and the second one is intravenous and again this inhalation is divided into a gaseous type of inhalation agents or a liquid types of in Harrisville agents so this cash is inhalation agents in through nitrox direct nitrous oxide into knocks I'm xenon this xenon is an ideal or a noble inhalational agent so if you take the liquid type of in Harriston agents these are all other examples so actually there are many of this listed in here but you can remember easily with the ending with pain in so if the in most of these in a liquid type of international agents we'll end with the aim so if you take this layer like chloroform cyclopropane drilling ether halothane and fluorine I so fluorine desflurane co feuding and methoxy feuding these all of the examples of liquid type of inhalation aliens so if you take the intravenous agents there of inducing agents and the slower acting drugs and this inducing agents in guilty open tone methoxy hangs it on top of all etomidate I'm hit a mine and if you see the slower acting drags again the slower acting drugs are subdivided into three groups the first group is Bentley Pines benzodiazepines which includes diazepam lorazepam and midazolam the second groups are like opioids which includes fentanyl Remmy fentanyl Soufan Tennille and alpha integral so you can remember with this mill at the end and the last group is of neuroleptic and the neuroleptics example there is only one drug in this category that is draw peridot so this is the classification of stages of anesthesia which is given by the doodle so if you see this classification there are four stages here and again the third stage there are four claims but in this thing you have to remember one point that is first plane and the second plane is that thing Bar will do the dental surgical procedures so if you take the stageman of general anesthesia it is also called as a stage of analgesia and here this stage will begin with the inhalation to the loss of consciousness and pupil if you see the pupil of the patient it will be normal and the other features includes like patient is conscious he'll be in a dreamlike State reflexes will be normal and displays are normal so all are not when only flexes and respiration will be normal in this stage one that is say the final is easier if you take the stage two it is called as a stage of excitement okay and this stage will start from the loss of consciousness to the gain of the chemical respiration if you see the pupil in the stage it will be large and diverse and other features like heartbeat blood pressure and muscle tone will be increased but as respiration will be irregular and there is the involuntary movements can be seen like micturition and the defecation can be involuntary in the stage two of anesthesia if you see the stage 3 as I have told it consists of four planes plane one two three and four and in this four planes the first plane and the second player important because our dental procedures can be conducted in these two planes so if the stage threes of surgical anesthesia where it starts or it extends from on staff regular respiration to the cessation of spontaneous breathing so in the plane one there will be of roving of eyeballs in the second plane you'll see loss of cornea and laryngeal reflexes in the third plane you'll see pupil starts dilation and right reflexes lost whereas in the fourth plane you will see that intercostal paralysis and the pupil is dilated here and in this other features like muscle tone heart rate increases but as blood pressure and respiration will be decreased coming to the last T's that is my de neri paralysis where there is cessation of breathing then because of this cessation of breathing there is circulation failure and finally leads to them death and if you take the case of pupil pupil here it will be of widely dilated pupil and muscles will be flabby files will be of thready pulse and blood pressure will be very low so these are the four stages of general anesthesia so coming to the general features of inhalational anesthetics which we have seen in that classification earlier so we have talked about the stages of anesthesia right so this stages of anesthesia can be differentiated only when a slow-acting a ginger used so this inherited anesthetics have two important properties that is maximum annular concentration which is also called as a Mac and blood gas partition coefficient okay so here there are two important points to remember one is potency that is this potency of the drug is inversely proportional to the minimum annular concentration and the second point is speed of on certain recovery of the drug and this speed of onset and recovery of the drug is inversely proportional to the blood gas partition coefficient if mini mark is of high for a drug then the potency of the drug will be low if blood-gas partition coefficient is high for a drug then speed up on certain recovery of the drugs will be low so these are the two important things if you see this make minimum annular concentration it will measure the potency of intra and the nitrous oxide will have a highest mark as it has a highest mark it is the least potent the second thing is methoxy fluorine which has a low mag as it has a low mark then it is most potent drug then we'll come to this blood gas partition coefficient it will determine the speed of onset and recovery so the fastest acting drug and with a low blood gas partition is best flooring and the slowest acting drug with high blood gas partition coefficient is methoxy Florence so these two are irreversibly proportional and these two are irreversible proportional so coming to the systemic effects of inhale additional agents so first we'll see the respiratory thing so in this respiratory thing the maximum respiratory depression is caused by the including whereas this actually this inhalation agents will blend the response to hypercapnia at hypoxia so the agent which do this thing is halothane and this halothane is also having under effect on respiration that is maximum drunk or dilation is caused by the halothane and the last is very important all these inhalation agents reduce the CVA activity but only if there is one inhalation agent which will not reduce that is ether ether will not reduce the ciliary activity so a respirator is done so we'll go with a cardiac now so in this cardiac actually all this inhalation agents will decrease the cardiac output except to drugs that is I so fluorine a - flooring and the maximum decrease I mean the drug which decreases the blood treasure in maximum amount is isoflurane whereas the increased blood pressure is cyclopropane as this isoflurane the black treasure it is a choice in control hypotension but as this cyclopropane increases the blood pressure it is used in the patient's or as a shock then maximum carrier contractility will be seen with the halothane and if you see the baroreceptor reflex it is blunted maximum with the halothane and it is not blunted or it is not affected with the eyes of Florence so this is where the cardiac effects of inhalation agents then coming to the liver toxicity actually there are three drugs which produce this liver toxicity three inhalational so one is a a Harrow tea the second is chloroform and third when is the methoxy fluorine then if you take the hepa total i mean that hepatotoxicity is done if you take the nephrotoxicity nephrotoxicity is caused by two drugs that is methoxy fluorine i see what fluorine okay and this me toxic fluorine is associated with vasopressin resistant polyurethane and failure this is very important to note why because this methoxy fluorine is high in fluoride content so because of this high fluoride content it will cause the vasopressin resistant renal failure and why this fluoride is a during this methoxy flow rain because this methoxy program is highly inflammable so the degrees that decrease the in flammability fluoride is added in this methoxy fluorine so if you take a black night oxide will cause a megaloblastic anemia and finally leads to the marrow suppression also and coming to the skeletal muscles maximum relaxation of the skeletal muscles is with the ether and remember all in Hoschton agents of the skeletal muscle relaxants except the nitrous oxide okay and in this system EK effects you have to people have to remember that what are the exceptions where there is no muscle relaxation where there is no decrease in blood pressure and where there is no blunt of reflex so this exceptional cases are important and here there are four important the general points that is maximum analgesia is produced by the trial in the good analgesia is produced by the ether maximum metabolic effect is shown by chloroform but as ether and cyclopropane can cause the hyperglycemia so if you take the inflammation in flammability in flammability which is the one of the important feature of this inhalation agent ether entropic cyclopropane will have a highly inflammable hence they should not be used when Cotter is done or cata we should not be used when when these two agents are used and there are three agents inhalational anesthetics like sevoflurane tri lean and methoxy Florence they should not be used when there is a closed circuit remember this point because they and even these things will have a these three three can react with the soda line okay if sevoflurane reacts with the soda line it will produce the component a which is a nephrotoxic whereas if thrillin reacts with the soda lime it will produce two agents two things that is dichloro acetone and the forcing this dichloro acetone is a neurotoxic and mostly this neurotoxicity can be seen with the fifth kind of seventh cranial nerves but as the phosgene agent there is a RDS that is acute respiratory distress syndrome can be seen with this foster and the last thing is methoxy fluorine when used in the closed circuit it can revive react with this rubber tubing which is very dangerous are very inflammable so hence these three things cannot be used when there is a closed circuit so this there are few gases which are filled in the cylinders so you which are used in the general anesthesia okay so this cylinders are have been given with some color coding which is very important for us and if you see this nitrous oxide it is given a color coding with a blue if you take the cyclopropane it is blue where a cyclopropane is of orange then for the air cylinder it is given with you can see in the picture there is a grey and right so this air is filled in a gray color the cylinder with a white veins and if you take the oxygen in this oxygen also there are two colors that means oxygen is filled with a black cylinder with white wings whereas carbon dioxide is filled in the gray color cylinder and helium is filled in a brown color cylinder and if you stake this intern ox also there are two colors you can see here so this is filled in a blue color cylinder with a white things so these are the very important things to note down as the color coding is very important to identify the types of that cash is agents so this is this part has been done and which explains or which gives you a brief idea of the general property of this inhalational anesthetics okay so stay home and stay well happy learning with MDS conta