One of the great advantages of operating on a patient's limb is that you can use a tourniquet to prevent bleeding. This will save blood and enable you to see his tissues more clearly.
You can use any of these:
A special pneumatic tourniquet which resembles the cuff of a sphygmomanometer. The pressure at which a tourniquet is applied is important; this is more easily controlled pneumatically, so a pneumatic tourniquet is much the best. Also you can, if necessary, let it down rapidly during an operation to perfuse the tissues, or to find arteries that need tying.
An Esmarch's bandage which is a strip of red rubber 7 cm wide and 2 metres long. It is satisfactory, provided: (1) You spread it out carefully over an encircling cotton wool pad. (2) You don't put it on too tight, especially on a thin limb.
A reliable sphygmomanometer. You may not have a special pneumatic tourniquet, so this is probably what you will have to use.
Never use a Samway's tourniquet. This is a rubber tube with a hook at one end. It too easily injures the tissues underneath it.
A tourniquet will prevent blood entering a limb, but it will not remove blood which was already there when you applied it. You can remove this blood in two ways: (1) You can raise the patient's limb for at least a minute to help the blood to drain away from it before you apply the tourniquet. This is the only safe thing to do if there is sepsis. It will leave a little blood in his vessels, which can be an advantage, because you can more easily see where they are. (2) You can wind an Esmarch bandage round his limb from its distal to its proximal end to squeeze out the blood. Then you can apply a pneumatic tourniquet (or a sphygmomanometer) round the base of his limb to stop blood entering it. Finally, you can remove the Esmarch bandage. This will provide an almost totally bloodless field, but is only safe if there is no sepsis.
A tourniquet has disadvantages: (1) If you apply too much pressure for too long over too narrow an area, you may injure the nerves to the limb, and cause a paresis; this is usually only temporary, but it may be permanent. A transient radial nerve palsy is common, even if you apply a tourniquet correctly. (2) If you forget to take a tourniquet off, so that it is left on for 6 hours or more, Volkmann's ischaemic contracture, myoglobinaemia, or gangrene may follow. This happens more easily if a patient has arterial disease. So apply a tourniquet carefully; record the time when you applied it, and don't leave it on too long (arm 1[1/2] hours, leg 2 hours, shorter times and lower pressures in children). (3) If a tourniquet is too loose, it may obstruct only the veins, and increase bleeding.
TOURNIQUET Conn, improved pneumatic with dial, in case complete, (a) adult, (b) child. One only of each size. A pneumatic tourniquet is one of the most useful surgical instruments, and is almost essential. Alas, few district hospitals have them.
BANDAGE, rubber, Esmarch 3 m[mu]75[mu]1 mm, fitted with tapes, two only. If you don't have an Esmarch bandage, cut one spirally from the inner tube of a motor cycle tyre, leaving out the elliptical pieces shown as in Fig. 3-12. The tube from an ordinary car tyre is too thick.
HANK (42 years) was to have a bunion removed. The junior resident was asked to apply an Esmarch tourniquet. He had never applied one before, so he just wound the whole bandage round the patient's unpadded leg. 10 days later at the follow up clinic the patient had a numb foot. LESSON Learn how to apply a tourniquet, before you apply one. IF YOU APPLIED A TOURNIQUET, IT IS YOUR RESPONSIBILITY TO REMOVE IT Fig. 3-11 TOURNIQUETS. A, don't use Samway's tourniquet, or you may injure the patient's limb. B, a pneumatic tourniquet is much the best. C, Esmarch's bandage is a roll of red rubber. D, the site to apply it in the arm. E, the site in the leg. F, use a rubber catheter as a finger tourniquet. G, and H, when you apply a tourniquet, take the time and record it. I, if you want to exsanguinate a patient's arm, raise it and then apply Esmarch's bandage, starting in the patient's hand. J, blow up the pneumatic tourniquet, then unwind the bandage, starting proximally in his limb. K, you can use Esmarch's bandage as a tourniquet.
TOURNIQUETS INDICATIONS. (1) A wound toilet in a patient's injured limb, particularly if this has to be followed by the repair of his vessels, nerves, and tendons. (2) Any hand operation, other than a very small one. Hand injuries, and hand sepsis. (3) The exploration and drainage of bones and joints, when this is anatomically possible, as in a patient's lower humerus, his elbow and parts distal to it. Or his lower femur, his knee, and parts distal to that.
CONTRAINDICATIONS. (1) The SS and CS varieties of sickle cell disease, but not AS heterozygotes. (2) Impaired circulation due to arterial disease. Sepsis is not usually considered a contraindication to the use of a tourniquet, but it is to exsanguination with an Esmarch's bandage.
CAUTION ! Never use a rubber tube tourniquet (such as Samway's), except on a finger, where you can use a catheter for a few minutes. Anywhere else, a rubber tube may damage the nerves of the limb.
ANAESTHESIA. A tourniquet is painful and a conscious patient will not usually tolerate one for more than 5 minutes. So the practical methods of anaesthesia are: (1) General anaesthesia. (2) Ketamine (A 8.1). (3) Axillary block (A 6.18).
SITES FOR APPLYING A TOURNIQUET There are only four of these: (1) The middle of a patient's upper arm (D, in Fig. 3-11). (2) His finger (F). Use a rubber catheter. This is only safe for a short procedure, such as draining a pulp infection. (3) His upper thigh, a hand's breadth below his groin if he is an adult (E). At this point the femoral artery lies close to the femur and is easily compressed.
CAUTION ! (1) Don't apply a tourniquet anywhere else. A tourniquet on the forearm is dangerous, so is one on the lower leg, because you may damage the common peroneal nerve as it winds round the neck of the fibula. (2) Tie a tourniquet to the operating table, to prevent anyone forgetting it, because the patient cannot later be lifted off the table without removing it. A tourniquet hidden under drapes can easily be forgotten.
THE SAFE TIMES for an adult of average build are[md]the arm 1[1/2] hours, the leg 2 hours. Shorten these times by 60% in a thin adult. Halve them in an 8 year old child. Apply a tourniquet to a finger for a few minutes only. The responsibility for keeping within these times lies with the anaesthetist, who should remind the surgeon every 15 minutes how long a tourniquet has been applied.
ELEVATE THE PATIENT'S LIMB for a few minutes before you apply any kind of tourniquet. If you are going to apply an Esmarch's bandage, now is the time to apply it.
PNEUMATIC TOURNIQUET. Place a folded towel, or a thin layer of cotton wool, around the limb at the site where the tourniquet is to be applied. Wrap this snugly round the patient's limb[md]it must not be loose. Pump it up to the appropriate reading for ''arm', or ''leg', on the scale. For a child use a lower presure as indicated on the scale. Drape it out of the way of the operation, but keep the dial where you can read it. If the bag becomes contaminated, autoclave it (2.4).
USING A SPHYGMOMANOMETER AS A TOURNIQUET. On a patient's leg apply the cuff over his femoral artery. On his arm apply it as if you were taking his blood pressure, or if necessary higher up his arm. Bandage it in place with a firm unyielding bandage, and fix this with adhesive strapping.
Blow up the cuff until his distal pulses just disappear. Remember the pressure, and let the cuff down again. When you want to use it, blow it up to 80 or 100 mm above the pressure which just stops the pulses. This is about 200 mm for the arm in an adult and 180 mm in a child. For an adult leg blow it up to 250 mm. Ask an assistant to keep the cuff at this pressure, and to inflate it as necessary.
CAUTION ! Don't inflate any cuff to more than 80 to 100 mm above the pressure that will just obliterate the pulse.
USING AN ESMARCH BANDAGE AS A TOURNIQUET Tape a folded towel or a thin layer of cotton wool in position over his limb. Apply Esmarch's bandage over about 12 cm.
Put on the first two layers of the bandage without pulling. Next, do a trial run to find how many turns are necessary to obliterate the pulse. Pull out the bandage to about three- quarters of its potential expansion length with each wind. Count the number of winds you need to obliterate the pulse.
When you want to apply it, apply five more winds than are necessary to obliterate the pulse. When you have finished, it should feel moderately firm, but not rock hard.
CAUTION ! (1) Don't apply a tourniquet over too narrow a band of muscles. (2) Don't ever wind on more than five turns after you have obliterated the pulse. Every turn may add 100 mm more pressure.
AT THE END [s7]OF THE OPERATION There are two ways of controlling bleeding after you have applied a tourniquet. You can release it, either:
(1) Just before you close the patient's wound. Use this method when you do a fine operation on his hand, for example. It will reduce the blood clot in his tissues, and the stiffness and fibrosis that this might cause. Release the tourniquet, raise his limb, apply large swabs to the wound, and press them for five minutes. Lactic acid will have accumulated in his anoxic limb and will make its vessels dilate immediately the tourniquet is released. As this is metabolized, they will contract again. Remove the swabs and tie any bleeding vessels that remain. Expect him to bleed into his dressings.
Or, (2) at the end of the operation after you have closed his wound. Use this method after operations in which clot in his tissues will be less important, as when you do a sequestrectomy (7.6). Tie any tie major vessels when you come to them during an operation. When the operation is complete, sew up the wound, apply a pressure dressing, and let down the tourniquet. Remove the pressure dressing 48 hours later. Usually, this is all that is necessary. Occasionally, the wound will bleed, so that you have to remove the dressing, open it and tie the bleeding vessel. If you need to immobilize an open fracture, loosely apply a well padded cast.
EXSANGUINATING A LIMB [s7]WITH ESMARCH'S BANDAGE INDICATIONS. Any operation in which you want a completely bloodless field, particularly orthopaedic operations.
CONTRAINDICATIONS. (1) Sepsis. (2) Amputations for malignancy. It may spread both of these.
METHOD. Apply a pneumatic tourniquet round the base of the patient's limb but don't blow it up.
Raise his limb and wind Esmarch's bandage tightly round it from the distal end proximally. As you do so it will squeeze the blood out of his veins. Blow up the tournqiuet. Finally, remove the Esmarch bandage to expose his bloodless limb.
POSTOPERATIVE CARE [s7]ALL METHODS Raise his arm in a roller towel (75-1), for his leg raise the foot of his bed. Observe the circulation in his limb at least hourly; the capillary reflex is important, so pinch his nail beds. If necessary, remove a pressure bandage or split a cast lengthways and open it at least 2 cm.
DIFFICULTIES [s7]WITH TOURNIQUETS If he CANNOT EXTEND HIS WRIST after the operation, he has a tourniquet palsy. The higher the pressure and the thinner he is, the greater the risk. Fortunately, this is usually temporary and recovers within 3 weeks and occasionally up to 6 months; but it can be permanent.
1[1/2] HOURS IN THE ARM AND 2 HOURS IN THE LEG LESS FOR THIN ADULTS AND CHILDREN Fig. 3-12 MORE TOURNIQUETS. A, you can cut an Esmarch bandage from the inner tube of a motor cycle tyre (a car inner tube is too thick). B, when you apply a tourniquet, tie it to the operating table, so that you do not leave it on by mistake. C, using a discarded glove as a finger tourniquet. B, after Sally Piper from the British Journal of Anaesthesia.