Physiologic preparation for surgery

Even though an urgent surgery is needed, the existing organ failures should always be corrected prior to, during or following the surgery, otherwise the favourable outcome of the treatment is unlikely.

The preoperative workup should be as short and efficient, in emergency being primarily aimed at reducing hypovolaemia and tissue dehydration. In patients with hypovolaemia, electrolyte and acid-base imbalances, infusion therapy including intravenous solutions of polyglucin, albumin, protein (and sodium bicarbonate in those with acidosis) with cardiovascular agents is immediately to be provided. To correct metabolic acidosis resulting from diabetes mellitus concentrated solutions of glucose with insulin are given.

In acute haemorrhage (and after the bleeding has been controlled) intravenous administration of polyglucin, albumin, and plasma is indicated. In sustained massive bleeding intravenous fluid therapy will be started with cannulas placed at least in two peripheral veins simultaneously while the patient is being transferred to the operating room where he/she is operated on to stop the bleeding. Intravenous fluid therapy is to be continued throughout surgery.

Emergency management of shock (traumatic, toxic or haemorrhagic with the bleeding already controlled) is aimed at:

a) eliminating the shock factor (pain control in traumatic shock; bleeding control in haemorrhage; detoxication therapy in toxic shock);

b) restoration of the circulating blood volume by way of intravenous fluid therapy;

c) restoring vascular tone with vasoconstrictors.

In most cases, surgery can be started with systolic blood pressure of at least 90 mm Hg. In the cases of haemorrhagic shock and sustained internal bleeding the surgery may be started before the patient's circulatory parameters have been corrected as the causative factor of the shock - bleeding - can definitively be controlled only by operating on the patient.

The physiologic preparation for the surgery must include the following:

1. Estimation of the surgical risk associated with the underlying circulatory disorders, diagnosis and management of the preoperative cardiovascular problems (e.g. preparations that improve microcirculation (rheopolyglucin).

2. Prevention and treatment of respiratory distress (oxygen therapy, improvement of pulmonary circulation, and mechanical ventilation in severe cases).

3. Detoxication therapy - fluid infusion, blood substitutes with detoxicating properties, forced diuresis with specific techniques - hemabsorption, lymph absorption, plasmapheresis and oxygen therapy.

4. Correction of fluid, electrolyte, and acid-base disorders.

Intravenous fluid therapy is aimed at restoring the circulating blood volume, eliminating dehydration, and normalising fluid, acid-base and electrolyte balances. Therefore, in hypovolaemia, electrolyte, and acid-base imbalances the abovementioned therapy is a matter of urgency (see Chapter VI).

Also, the preoperative period may require that a number of manipulations be performed. If, for instance, the patient ate the previous day or shows the signs of intestinal obstruction, the stomach is to be lavaged before the operation to prevent vomiting or regurgitation during general anaesthesia.

Stomach lavage. To perform gastric washout the following equipment is needed: a nasogastric tube, funnel, bowl, plastic apron, pair of gloves, a cup and jug with boiled water. The patient's condition permitting, he/she is made to lie (or sometimes sit on a chair); the end of the tube will be lubricated with vaseline and inserted into the patient's throat (they should try to swallow the tube while the physician passes it into the oesophagus). On reaching the first mark on the tube (50 cm) the end appears at the cardiac portion of the stomach. If the stomach is full, the contents start gushing out immediately and are thus to be directed into the bowl. When the spontaneous flow stops, a glass funnel will be attached to the outer end with subsequent aspiration of the gastric contents. To do this, the funnel is raised 20-25 cm above the mouth level and 0, 5-1 l of water that passes into the stomach is poured into the funnel. To prevent air from entering the stomach, the water must flow continuously. When all the water in the funnel has been emptied into the stomach, the tube with the funnel still attached is then lowered into the bowl (below the knee and bed levels for the patient sitting and lying, respectively) with the funnel cup in an upward position. After the funnel has been filled up with the gastric contents it is emptied into the bowl or bucket. If the amount of fluid emptied is less than that given, the position of the tube is changed - it can be pushed a little further or pulled back, the funnel being either gently pushed down or pulled out. Thereafter, the contents usually starts to flow out, the procedure being repeated after the gastric contents have stopped flowing. The stomach should be washed until clear water starts flowing out.

When the flow stops, irrigating syringe has to be used - pour with force and aspirate the water, the procedure being repeated several times. As a matter of fact, pieces of food particles that cause obstruction are evacuated in this process; alternatively, the tube can be removed and reinserted.

Finally, the tube is to be removed gently into a napkin placed at the patient's mouth.

Insertion of urethral catheter. The procedure is applied preoperatively to empty the bladder in urinary retention, monitor the urine output during operation and prevent bladder injury during pelvic surgery or laparoscopy.

The equipment required includes a sterile rubber catheter, two sterile forceps, sterile vaseline oil, gauze swabs, furacilin solution 1: 5000 or 2% boric acid. All these are to be placed on a sterile tray. The hands are washed with running water and soap, and cleansed with alcohol for 3 minutes.

The male patient is put supine with his legs bent in the hip and knee joints and opened apart. The tray or pot for the collection of urine is placed in between the patient's legs. The urethral meatus and the surrounding areas are cleansed thoroughly with gauze swabs dipped into antiseptic. Using the forceps the catheter is picked 2-3 cm from the end and dipped into the sterile vaseline oil. The left hand (between fingers 3 and 4) is used to fix the penis while fingers 1 and 2 to open the outer end of the urethra. Using the forceps, the catheter is inserted into the urethra and subsequently into the bladder. Passing through the isthmus of the urethra the catheter can encounter resistance. Once the catheter is in the bladder, urine should flow freely into the disposable basin provided. The volume, colour and turbidity of the urine are noted. The catheter is removed after the bladder has been completely emptied.

When the bladder cannot be emptied with the soft catheter, a metallic one should be used, which, however, requires much experience for the danger of injuring the urethra.

Passing the catheter in a female patient is technically easier since the female urethra is shorter, wider and straighter. It is performed with the woman supine and her legs apart. The patient lies on the bad-pan. Running water is used to wash the perineum, the smaller lips being opened with the left hand fingers. Cotton swabs soaked in antiseptic are used to cleanse the external urethral meatus. With the right hand and forceps the catheter is passed into the urethra. A metallic catheter for women can be used, which is held in such a way that the beak points upwards. The catheter is easily inserted until urine appears. On emptying the bladder the catheter is removed.

Enema. To perform a cleansing (purgative) enema the following items are necessary: Esmarch's cup with a rubber tube, a tap or clamp, and a glass or plastic tip (end-piece). 1-1, 5 l of water are poured into the cup and fills the tube to evacuate all the air, the tube is then closed with the tap or clamped at its end. The tip (end piece) is to be lubricated with vaseline or oil. The patient will be placed on the left side (on the side of the sigmoid colon) to insert the tip into the rectum 10-15 cm deep. The clamp is then removed or the tap opened and the cup gradually raised. After the water has started flowing slowly into the rectum, the end piece is removed and the patient turned to lie supine on a bed pan or receiver (they are made, if possible, to sit on the closet). It is recommended that the water be allowed to stay as long as possible in the rectum before evacuation.

Cleansing («siphon») enema. This type of enema is indicated when ordinary enemas are ineffective in evacuating faeces (intestinal obstruction, faecal impaction). The equipment used for the cleansing enema includes a rubber or plastic tube fitted onto a large glass funnel. The patient should be placed on their left side at the edge of the bed or couch. The funnel will be filled with water, the clamp opened to drive away the air and then closed again to fill up. The tip of the rubber tube is inserted into the rectum 10-12 cm deep, the clamp being removed and the funnel raised to allow the water to flow into the large intestine. 2-3 l of water are usually passed at a time, with constant pouring it into the funnel so as to avoid a break in the flow of water and to prevent air from entering the intestine. When the patient expresses the urge to defaecate the funnel is lowered below the bed level and the water flows out together with the faeces and air. When filled up, the funnel is emptied. Filling with water and evacuating the intestinal contents are repeated several times, using totally 10-15 l of water. Such signs as massive evacuation of the faeces and gases, a relief of pain and reduction in abdominal distension in patients with intestinal obstruction are favourable.

Prevention of endogenous infection. All chronic infections (e.g. tooth decay, tonsillitis, pharyngitis and pyogenic dermatitis) should be sought and treated preoperatively. When the impending surgery has a relative indication, the patient can be discharged to eradicate the infection before admission back to the surgery.

The surgery for a lung abscess involves bronchoscopy to remove, at least initially, inspissated purulent debris. For the patients to be operated on for a large intestinal condition a soft diet, cleansing enema and oral broad-spectrum antibiotics for a few days preoperatively are ordered.

In addition, the patient will be examined by the anaesthetist who prescribes the appropriate anaesthetic technique (see Chapter II).

Preliminary preparation of the operative field. On the day preceding that of the operation a cleansing enema is performed, the patient takes a hygienic bath and changes into clean fresh underwear; immediately before transfer of the patient to the operating theatre the exposure area will be dry-shaved.

The operative field should be prepared differently in case of an ulcer or wound: the dressing is removed and the wound is covered with a sterile dressing, the skin around the wound being cleansed with benzene or ether and the hair dry-shaved. All movements - cleansing the skin or shaving the hair - must be directed outward from the wound so as to reduce the risk of contaminating the wound. On shaving, the dressing should be removed and the surrounding skin cleansed with 5% alcohol solution of iodine, with the wound being covered with sterile dressing. In the theatre the wound is again scrubbed widely with alcohol solution of iodine and isolated with sterile operating sheets.

Anaesthetic technique. Before the patient is taken to the operating theatre he/she is given specific drugs to reduce the risk of adverse effects of anaesthesia and surgery itself, as well as to avoid negative events intra-operatively.

⇐ Предыдущая26272829303132333435Следующая ⇒

Поделиться: