Intravenous procedures (1970s)

since calculations and visual demonstrations have confirmed all my suppositions i am obliged to conclude that in animals the blood is driven round in a circuit with an unceasing circular kind of motion in this way william harvey englishman physician to the king and professor of anatomy at the london college of physicians announced his theory of blood circulation to the world in 1628 his proof was a masterpiece of deduction he showed that each time the heart contracted it ejected two fluid ounces of blood in the course of an hour therefore the heart beating an average of 72 times per minute pumps out 8640 ounces of blood since the weight of this blood would be three times greater than the weight of the average human being there could be but one explanation for the apparent contradiction the body must contain a limited amount of blood which the heart pumps over and over again through a fixed circulatory system harvey's discoveries are as important today as they were 350 years ago much modern therapy depends on utilizing the circulatory system almost as a means of transport for administering drugs for fluid care for routine maintenance of fluid and electrolytes in patients unable to ingest and for artificial feeding when the oral root is not possible all these and the obtaining of blood samples depend upon entry into the system by means of venipuncture the first stage in utilizing the blood circulation for therapy is usually preparing the drip this is relatively easy and as such is usually handled by a nurse there are many types of drip set available but the most frequently used is the administration set for the infusion of blood or solutions the procedure is simple enough after the set is removed from the container close the clamps and push the cannula through the bung of the solution container then squeeze and release the filter chamber gently several times until full and if necessary squeeze and release the drip chamber until about one-third full if an airway is required open the slide clamp on the air inlet tube then open the clamp on the drip tubing and expel the air by letting the fluid run through the set then reclose the clamp the solution is now ready to be passed into the circulatory system and you must decide from which point in that system although most superficial veins are suitable for entry the preferred sites are the anterior aspect of the forearm the radial side of the wrist the dorsum of the hand the veins of the anticubicle region and occasionally the veins in the dorsum of the foot or at the ankle entry at all these sites is relatively simple and becomes even more simple with practice but there are four groups of patients whose veins are notoriously difficult to cannulate first the infant here the veins are obviously very small and it's often more practical to enter by the scalp vein a process which is now much simpler than it used to be secondly the geriatric where the veins are tortuous and fragile and the skin has lost its elasticity thirdly the obese where superficial veins are small and scarce and finally for obvious reasons the vasoconstricted patient clearly then site selection is determined by the condition of the patient and the purpose of the intravenous procedure the last preliminary stage is the choice of the appropriate intravenous device a choice usually made between the catheter the cannula or the increasingly accepted winged needle this is the cannula a tapered plastic tube formed around a needle which provides the method of entry peter williams age 36 gastric outside causing considerable internal not bleeding well hello mr williams again now remember i said you'd have to have a transfusion it won't take long right sister oh by the way is mr williams left or right-handed good prepare the cuff would you just going to put a cuff around your arm helps make the veins stand out right it's often found that veins in the forearm are readily accessible if the arm is allowed to hang down for a time at a level below the heart because this induces vein distension if the veins stand out well then manual compression will easily be sufficient to fill them however it's usually necessary to apply a tourniquet which must be tightened just sufficiently to obstruct venus return without stopping the arterial flow good mr williams i'd like you just to drop your arm over the edge of the bed if you would where the veins are small and deep like slapping of the skin above the chosen vein will help increase dilation and facilitate entry where it's still difficult to make veins stand out the application of heat to the whole arm is often successful and may be essential if other methods fail when the vein is standing out the site is swabbed clean now what we're going to do is give you a little local anesthetic just so she won't feel anything afterwards the injection of a local anesthetic with a very fine gauge needle is obviously kinder to the patient and helps him relax for what to him is an unnerving procedure remember patients are usually conscious during cannulation and an explanation of what is happening tends to have a calming effect many doctors prefer to start the procedure by nicking the skin above the vein with a scalpel this makes it easier and quicker to insert the cannula the cannula is usually introduced through the skin directly above the vein and as parallel to the skin as possible this is so that vein entry will not be at so steep an angle as to risk penetrating the firewall of the vein then the cannula is advanced as far into the vein as possible at this point the blood flashes back up the cannula now pressure is applied to the skin and the cannula held firmly in the vein while the needle is withdrawn when the cannula has been successfully placed it's connected to the lower fitting of the drip set and strapped to the skin using a length of half inch tape fold it around the base of the cannula a further length of wider tape is used to hold the loop drip set tubing firmly to the arm the hole of this is now covered with an adhesive dressing to ensure that any movement of the drip set will not be transmitted to the cannula within the vein right normal yeah wasn't too bad was it leave it at 40 drops a minute please the butterfly needle has gained widespread acceptance because of its ease and simplicity in use originally developed for use in baby's scalp veins it proved so successful that its use spread to other difficult procedures the elderly the obese and the vasoconstricted patients clearly the advantages of butterfly sets in these difficult procedures made equally good sense in routine venipuncture so the larger sizes were developed to provide the flow rates necessary for routine adult infusions the short sharp bevel makes for easy vein entry and greatly reduces the risk of cutting out the thin wall needle gives maximum flow within minimum diameter the wings provide a positive finger grip and firm anchor for taping the flexible tubing means that any movement in the drip set is not transmitted via the needle to the patient the risk of vein trauma is thus virtually eliminated right here we are thank you yeah fine it's your first uh operation yes yes not to worry nothing too serious elizabeth butch 23 diabetic for a while we've got to keep your sugar level up now i just want you to clench and unclench the fist hard as you can keep doing that's it this will just feel a little bit cold for a minute don't forget when the vein has been selected the sight is swabbed clean the needle is short in length effectively reducing the risk of vane trauma the thin wall design ensures maximum flow within minimum diameter and the flexible plastic wings fold back providing the doctor with absolute control the lure fitting is connected to the drip set and fluid is flushed through it the needle is now ready for insertion there it is grasp the wings of the needle between forefinger and thumb and pass the needle through the skin directly above the vein and parallel to it when the tip penetrates the vein blood will flash back along the tubing indicating vein entry the needle can now be advanced further along the vein for greater stability yeah didn't hurt did it not really no no the clamp on the drip set is opened and the fluid can be seen passing along the tubing into the vein at this point the wings which gave such smooth control for the vein entry now fold flat to provide a secure base for strapping this is done quite simply by laying two short lengths of tape across the wings and parallel to the needle and applying a third slightly longer tape across the needle at the same time forming a loop in the tubing so that if the patient jerks her arm the movement will be taken up by the loop and not transmitted to the needle in the vein you move your arm yes very well good fine that's it of the many devices available for intermittent therapy only the butterfly int has the advantage of having a latex injection site separated from the needle by a short length of flexible tubing because of this tubing there's no movement or pressure in the vein at the moment you pierce the injection site on the lure fitting and of course as the tubing is flexible you can inject from any position the third venipuncture device is the catheter which is sometimes used for entering the veins of the anticubicle fossa when the veins of the forearm are not practicable for cut down procedures for long-term parenteral nutrition and for such specialist techniques as central venous pressure monitoring the long catheter is inserted into the vein in the usual manner and then threaded along as far as required this process could be time consuming and has now been simplified by the recent development of the drum cartridge catheter this new device has made the placement of an intravenous catheter in the true venous system easier and since monitoring of central venous pressure is a valuable aid in controlling response to intravenous therapy this procedure will probably be used more frequently central venous pressure is a measure of effective circulating blood volume relative to the ability of the heart to handle that volume and serial measurements can serve as a diagnostic aid and therapeutic guide to circulatory dynamics the conventional routes for venipuncture are the arm the internal and external jugular and the subclavian vein in this case the arm root has been selected to insert the catheter the needle guard is opened and venipuncture is carried out this x-ray film shows the movement of the catheter along the vein the thicker line is a metal stilette which provides the necessary rigidity for placement insertion of this type of catheter is not without its dangers and if obstruction is felt the unit should be withdrawn and the procedure restarted once in position the needle must be immobilized and the retaining ring should be fastened into place and strapping applied to the needle guard the stilette can then be removed and the catheter connected to a drip set with an extension tube for monitoring the pressure readings readings of cvp are taken in relation to a reference point on the patient's body such as the mid axillary line should the patient be moved the manometer must be realigned it's wise to measure the length of any needle outside catheter after it's been withdrawn from the vein to ensure that embolism of the tubing has not occurred if the catheter has been placed correctly the fluid level will show a rise and fall with respiration and there may also be a faster oscillation due to the heart's action when terminating an intravenous infusion stop the flow of fluid by means of a clamp with the butterfly needle held firmly in place gently remove the adhesive tape by which the needle and adapter were secured with one hand place and hold a sterile swab over the site of injection with the other hand keep the hub of the needle flush with the skin and slowly withdraw the needle taking care not to drag the tip against the posterior wall of the vein secure the swab over the injection site and apply pressure for two or three minutes to avoid a hematoma skill in venipuncture is acquired only with practice but the development of devices like the butterfly has meant that a once difficult procedure has been remarkably simplified harvey would doctors have approved you