Intravenous anaesthesia: No. 6 (1944) Pt. 1 of 2

I the the barbiturates in common use are ventic evipan otherwise known as hexobarbitone and penty penty is in many ways the most efficient and forms the subject of this demonstration here is the apparatus you'll need sterile 10 cubic cm syringes and 20 cubic cm syringes with eccentric nozzles a wideborn needle or canula for mixing the solution a hypodermic needle for the actual injection ether or sterile water in a bowl for rinsing the syringes sterile G swabs a holder for the ampols ampol files an artificial Airway quarter in adhesive tape for fixing the syringe to the forearm or this rubber device for the same purpose there should also be a cylinder of oxygen or better an anesthetic machine if it's available in the theater there must be an armrest rubber pad and wrist strap for securing the patient's arm during the operation penty is supplied as a sterile powder in 1 G and half G ampuls amples of distilled water are supplied separately though sterile tap water saline or melted snow can be used in emergency break off the tops of the ampols before washing your hands and making up the solution now rinse the syringe and canula draw up the distilled water and squirt it into the powder which will dissolve at once fill the syringe with a solution which should be straw colored and quite clear attach the hypodermic needle and lay the syringe on the sterile towel the solution may be used up to 24 hours after preparation first inspect the patient's veins if they're deeply embedded in fat they can be made more obvious by hot fermentations applied for half an hour before the operation you will find usually that manual compression is sufficient to distend the veins if a touray is used it should be of soft rubber and tied gently over some material conveniently the patient sleeve the patient can help to make the veins more prominent by opening and closing his fist the best vein to choose is one which will enable the syringe to lie comfortably on his forearm either of these two would do but not this one alternatively you can often find a suitable Vein on the front of the wrist or on the back of the hand success in Vena puncture depends largely on the sharpness of your needle this should be a number 17 with the bevel cut at 30° this needle has a slight hook so you should touch up the point with a sterile hone now clean the skin with Spirit or ether choose a point in the skin in line with the vein but at a short distance from the intended sight of puncture hold the charged syringe with the needle at about 30° to the surface and with a bevel upwards pierce the skin with a sliding action when the needle is moving freely in the subcutaneous layer pick up and enter the vein pass the needle along it for about half an inch to prevent it slipping out now withdraw the plunger gently if the needle is in the vein blood will be aspirated into the syringe the tour or hand can now be released and the injection made pental is irritant if injected subcutaneously but it doesn't lead to sloughing and it requires no treatment the puncture must be done smoothly any jerking or stabbing movement is likely to result in transfixion of the vein if the brachial artery is entered accidentally as in this case the patient will complain of pain in the hand and forearm when you make the injection withdraw the needle immediately and make a fresh puncture at another side finally fix the syringe in position with adhesive tape The Eccentric nozzle allows the syringe to rest closely on the forearm without the needle distorting the vein you must be careful that the patient doesn't Bend his arm or the needle may break off in the vein some competent person must be in charge of the arm until it's fixed in position now we'll follow through the most important parts of an actual anesthesia this is a healthy woman of 23 who is to have an inguinal Hern orapi predication reduces the necessary dose of penty by about 1/3 and makes smoother the course of anesthesia she had an injection of 1/3 of a grain of pum and 150th of a grain of Scopolamine 3/4 of an hour ago the dose would have been hared for a patient between 14 and 18 years of age or over 60 or if her resistance had been lowed by anemia CIA or shock the breathing will be very quiet to make it more obvious du we are attaching a whsp of cotton wool as an indicator the essential point you must bear in mind is that pental is an anesthetic that depresses breathing this depression limits the depth to which the anesthesia may be taken there is no standard dose a patient must be given what he needs and no more the patient should be encouraged to relax and to compose herself for sleep don't ask her to count this is valous and tends to disturb the smooth progress of the induction individuals apparently similar in physique and habit vary so greatly in their behavior under barbiturates that it's impossible to judge the dose in Advance give each patient the same initial rapid injection of 3 cubic cm note the time and watch their reaction closely with experience you will then be able to form a very reliable estimate of their susceptibility the patient will lose cont ious in about 30 seconds this will usually be followed by a period of apnea lasting 5 to 20 seconds corresponding to the maximum effect of the pental on this mainly you judge their reaction with the effect of the pental wearing off and with carbon dioxide accumulating she starts to Breathe Again equilibrium is established with a higher level of Alva carbon dioxide and she won't again become apneic except with much deeper anesthesia the greatest care must be taken from the start to maintain an unobstructed airway most patients will breathe very comfortably if the head is turned to one side on the pillow support the chin if necessary don't use an artificial Airway if you can avoid it as it tends to stimulate lenel spasm 3 minutes have passed and the patient shows signs of waking up while the towels are applied inject another 1 to 2 cubic cm and again see that the airway is clear all is now ready again note the time and inject 2 to 4 cubic cm according to the reaction to the initial dose this patient is having 3 cubic cm until you have gained sufficient experience it's better to ER on the side of caution you can always inject more but you can't withdraw what you've put in at the moment of deepest anesthesia 45 seconds later the surgeon makes his incision during the operation further injections of one or two cubic cm are made as indicated usually by a slight movement of the arm or leg not often quite as marked as in this case anesthesia can be deepened so rapidly and so easily that its General level can and therefore should be much lighter than would be practicable with an inhalation anesthetic it must never be so deep that the breathing stops in some Orthopedic operations this woman has a fractured leg even slight movement is not permissible then you must take deeper breathing as an indication for further injection note that the breathing has now become shallow you will have noticed that the patient's eyes have not once been looked at during these demonstrations the loss of eye reflexes is variable and doesn't follow the familiar sequence found with the inhalation anesthetics you have only two reliable signs if she does not react to surgical stimuli she's deep enough if she's breathing she's not too deep pental is an anesthetic that depresses the breathing nearly all difficulties that may arise are related to this owing to the depression obstruction may be silent there's no warning stridor as with ether and unless you're watching closely the first sign of danger may be cyanosis with its added depressant effect you must keep the airway clear in this demonstration the closed rebreathing bag is used to make it more obvious the patient's tongue has fallen back obstructing his Airway his rather feeble attempts at breathing are not enough to draw air past the obstruction and the bag doesn't move when his chin is supported the obstruction is relieved and the bag moves in light to moderate anesthesia with pental the LEL reflex is sensitive and disappears only with very deep anesthesia the stimulus of trickling saliva of surgical trauma or of an artificial Airway May produce lenal spasm this patient has developed spasm from one of these causes quite literally a fatal error is to inject more pental in an effort to abolish the spasm stop the operation pull the airway halfway out to remove one possible cause of irritation support the jaw and try artificial respiration a with oxygen Under Pressure you'll find this more effective than compressing the chest which is usually already fully contracted after you have relieved the cyanosis you can in 2 cubic cm of cardazol or 5 Cub cm of coramine intervenous if you think they are necessary but oxygen is much more important than any stimulant drugs the patient is safe under pental only so long as his color is good if he becomes cyanosed his pulse will weaken and may become irregular and his heart will stop sooner than it would with ether almost as soon in fact as with ethylchloride or chloroform this man has stopped breathing because of an overdose his color is beginning to deteriorate and his pulse is weaker put in an artificial Airway get summoned to support the jaw and start artificial respir ation his color improves at once and his pulse returns you can easily delay the return of breathing by over ventilating him if you have it at hand oxygen with 5% carbon dioxide will prevent this but never at any time give a patient undiluted carbon dioxide you must keep up artificial respiration until he has had time to detoxicate the excessive penty when he will breathe on his own blood pressure fall is usually slight but it may be severe with an overdose or if cyanosis develops and it may prove fatal in a patient who is Gravely ill here is a case where the pental has been given correctly the systolic blood pressure is 120 mm of mercury with an initial injection of 5 cubic cm it falls to 110 mm and rises again falling about 10 mm with each injection the general level Remains the Same same this patient is a healthy man with a blood pressure of 130 over 80 with a rapid injection of 10 cubic cm the systolic blood pressure Falls 40 mm and returns in due course to normal at the time he was apneic in a patient with high blood pressure large doses may result in a precipitous fall which has the effect of still further deepening the anesthesia in this case the systolic blood pressure is 190 and the diastolic 110 with the injection the systolic blood pressure Falls to 90 and does not return to normal during the operation artificial respiration with oxygen was given recovery is much slower after large doses than after small a total dose of 1 GR shouldn't be exceeded except in emergency though as much as six G has been used on occasion if the operation is still far from completion you must be prepared to change over to an inhalation anesthetic in most cases as here nitrous oxide and oxygen is sufficient single-handed administration of the anesthetic by the surgeon is unjustifiable except in Urgent cases accidents of the type you of seene may occur and without proper supervision by the NST they are likely to prove fatal for all these reasons pental is at its best in minor surgery or for the induction of anesthesia to be maintained by another agent and should be confined to the the depth of anesthesia required for adequate muscular relaxation in abdominal operations produces mocked respiratory depression and it's unsafe except in expert hands intravenous anesthesia calls for closer retention on the part of the entist than do other methods but provided its limitations and difficulties are understood it will be found most valuable the only absolute contraindication to pental is already existing sosis in this case it was due to tral obstruction but as we have seen many other circumstances call for the greatest care in its use of these the most important is the existence of an actual or potential obstruction to the airway here a fractured jaw with a swollen tongue here a quinzy only a very experienced anesthetist would be justified in giving them pental you must not use it for intraoral operations such as tonsilectomy where blood might reach the ltin unless you have the airway controlled you must use an endral tube pental is a valuable anesthetic in shock but here as after severe Hemorrhage the margin of safety is reduced and you must keep the dose to the minimum it is simplest to inject the pental into the rubber tube conveying the intravenous plasma or saline these patients need oxy especially with an anesthetic that depresses breathing it's quite satisfactory for children of any age provided a suitable vein can be found and provided the general principle of suiting the dose to the needs of the individual patient is kept in mind kidney disease is no contraindication it was was given to this man four times in the space of 3 weeks and it can be used in small doses to induce Anesthesia where there is liver disease even including jordis pendy is a delightful anesthetic from the patient's point of view induction is always as rapid and uneventful as in this case you saw at the end of the operation the patient requires little or no attention she had 16 cubic cm of pental for an operation lasting 35 minutes she woke very quietly as from a natural sleep 1 and a/4 hours afterwards but remembers nothing until 3 and 1 half hours afterwards during which time she dozed at intervals there was no norer or vomiting she was given morphine as soon as she was able to complain of pain had she been going home someone would have accompanied her although she appeared completely recovered and she would on no account have been allowed to drive a car on the same day for