The preoperative period encompasses the time between the patient's admission to the hospital and start of the operation.
The duration of the period may vary with a number of factors, such as
• type of disease;
• severity of the patient's condition;
• nature of the surgery.
The main purposes of the preoperative period are as follows:
1) to define the problem (i.e. to make the diagnosis);
2) to identify other conditions that may influence anaesthesia or surgery (i.e. to determine the indications and contra-indications, urgency and type of operation to be performed);
3) to prepare the patient for the operation (to minimise the risk associated with the surgery and that of postoperative complications):
• to evaluate the functions of all body systems (including the operative site) and thus to prevent their deterioration;
• to identify and, whenever necessary, eradicate endogenous infection;
• to prepare the patient psychologically;
• to choose and provide the patient with appropriate anaesthesia.
Depending on the urgency operations are classified as:
1. Emergency operations should be performed either immediately or within several hours after the patient's admission to the surgical unit.
2. Urgent operations are to be undertaken within a few days after admission.
3. Elective operations are those that have been previously scheduled.