Chapter VIII. POSTOPERATIVE PERIOD. Surgeries are commonly classified depending on their urgency and the chance of curing the patient.

An operation, or a surgery, is a specific mechanic intervention upon a part of the body for diagnosis or treatment.

Surgeries are commonly classified depending on their urgency and the chance of curing the patient.

Depending on the urgency, there are the following types of operations.

1. Urgent, i.e. the ones to be performed immediately or within a few hours following the patient's admission.

2. Emergency, i.e. the ones that should be done within several days after the patient's admission.

3. Scheduled, i.e. the ones performed according to schedule (the date of the operation is not fixed).

Each operation may be either radical or palliative:

1. Radical, i.e. the one intended to extirpate the disease, usually malignant, completely.

2. Palliative, i.e. the one intended to relieve symptoms without hope of cure.

An operation can also be a one-stage or multistage surgery. Each step of a one-stage operation follows the previous one in succession, while a multi-stage operation consists of a series of surgeries performed on different days.

Current methods of anaesthesia and intensive care allow for two or more operations be done simultaneously in the same patient.

Microsurgery requires that the object to operate on be magnified at least 3- to 40-fold, which is achieved with special glasses or a microscope and that special microsurgical instruments and the thinnest sutural strips be used.

Endoscopic (e.g. laparoscopic, thoracoscopic) operations are performed with special devices.

Endovascular operations are closed intravascular interventions done under the X-ray control, e.g. widening a narrowed vessel with a special catheter; removing artificial occlusion of the vessel, or embolization; elimination of intravascular atheromata, etc.

The surgical operation consists of following main steps:

— operative access;

— primary step (operation itself);

— finishing the operation, suture of wound.

All the events associated with the operation itself, including the operation stress and effect of anaesthesia, are referred to as the postoperative period, while the consequences of surgery are called as the postoperative condition, or «postoperative disease».

The operation stress caused by the surgery results from various factors such as fear, excitement, pain, the effect of anaesthetics, trauma, wound formation, abstinence from food, being bed-ridden, etc.

The development of a stressful state is promoted by the following factors:

1. The patient's general status before and during the surgery, which depends on the type of disease.

2. The traumatic nature and duration of the surgical manipulation.

3. Inadequate anaesthesia.

In terms of its duration, the postoperative period encompasses the period from the end of the operation up to the patient's complete recovery or his/ her recognition being disabled.

The following stages of the postoperative period are identified:

• early postoperative period (from the end of surgery to the time the patient is discharged from hospital);

• late postoperative period (from the time the patient is discharged till the time he/she recovered fully or is found disabled).

Both surgery and anaesthesia bring about particular pathological changes in the body, which are the manifestations of the body's response to the surgical trauma. This induces defensive mechanisms to eliminate the consequences of the trauma and therefore restore homeostasis. The surgery affects the balance in the rate of metabolic (anabolic and catabolic) reactions rather than launches new metabolic events. The postoperative state divides into the three phases:

• catabolic phase;

• resolution phase;

• anabolic phase.

The catabolic phase lasts three to seven days. The period tends to be more acute when the serious changes in the body are caused by the severity of the principal condition or the extent and hazards of the surgery itself. The catabolic stage may also be prolonged and worsened if postoperative complications develop. These include the following:

• bleeding;

• pyogenic infections;

• hypovolaemia;

• fluid, electrolyte, and acid-base disorders.

The improper management (e.g. inadequate analgesia or nutritional support, parenteral nutritional support, pulmonary hypoventilation) is known to contribute to prolonged catabolic phase as well.

The catabolic phase is a defensive body reaction aimed at enhancing the resistance of the body by way of prompt transfer of the energetic and plastic materials to the vital organs. It is characterised by specific neuroendocrine reactions: activating the sympathetic nervous system and adrenals, hypothalamus and pituitary, intensive synthesis with subsequent release of catecholamines, glucocorticoids, aldosterone and ACTH into the blood. This results in an increase in the amount of glycogen in the circulation, accompanied by a fall in insulin blood levels. Furthermore, intensive synthesis of angiotensin and renin occurs. The neurohumoral disturbances alter the vascular tone to cause vascular spasm and defects in microcirculation and tissue perfusion, which, in turn, leads to hypoxia, metabolic acidosis, electrolyte imbalance, fluid redistribution, an increase in blood viscosity and blood cellular stasis. This further affects the extent of disturbance in the tissue redox processes that take place in the acceleration of anaerobic glycolysis as a result of tissue hypoxia. The myocardium, liver and kidneys are therefore the first to be affected.

The catabolic phase also involves accelerated protein breakdown which is manifested by the decrease in muscle and connective tissue protein, and, which is even more important, by the depletion in enzymes. The proteolysis in the liver and digestive tract is the fastest to occur, while that in the striated muscles takes significantly longer to complete. A 24-hour hunger, for example, decreases the amount of liver enzymes by 50%. The total loss of body protein during the postoperative period tends to be considerable. During ten days following uncomplicated stomach resection without parenteral nutritional support, for example, the patient loses 250 to 400 g of protein, which is twice as much as the amount of plasma protein and corresponds to the loss of 1, 700 to 2, 000 g of muscle weight. The loss of protein appears even greater if bleeding or postoperative purulent complications develop. This inflicts a particular hazard on those patients who have been hypoproteinaemic preoperatively.

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