Operative Phase
The operative (or intra-operative) phase begins the moment the patient is taken into the operating room. Two of the major factors to consider at this phase are positioning and anesthesia.

POSITIONING.-The specific surgical procedure will dictate the general position of the patient. For example, the lithotomy position is used for a vaginal hysterectomy, while the dorsal recumbent position is used for a herniorrhaphy. Regardless of the specific position the patient is placed in, there are some general patient safety guidelines that must be observed. When positioning a patient on the operating table, remember the following:

Whether the patient is awake or asleep, place the patient in as comfortable a position as possible.

Strap the patient to the table in a manner that allows for adequate exposure of the operative site and is secure enough to prevent the patient from falling, but that does not cut off circulation or contribute to nerve damage.

Secure all the patient's extremities in a manner that will prevent them from dangling over the side of the table.
Pad all bony prominences to prevent the development of pressure areas or nerve damage.

Make sure the patient is adequately grounded to avoid burns or electrical shock to either the patient or the surgical team.
ANESTHESIA.-One of the greatest contributions to medical science was the introduction of anesthesia. It relieves unnecessary pain and increases the potential and scope of many kinds of surgical procedures. Therefore, healthcare providers must understand the nature of anesthetic agents and their effect on the human body.

Anesthesia may be defined as a loss of sensation that makes a person insensible to pain, with or without loss of consciousness. Some specific anesthetic agents are discussed in the "Pharmacy" chapter of this manual. Healthcare providers must understand the basics of anesthesiology as well as a specific drug's usage.

The two major classifications of anesthesia are regional and general.

Regional Anesthesia.-Regional anesthetics reduce all painful sensations in a particular area of the body without causing unconsciousness. The following is a listing of the various methods and a brief description of each.

Topical anesthesia is administered topically to desensitize a small area of the body for a very short period.
Local blocks consist of the subcutaneous infiltration of a small area of the body with a desensitizing agent. Local anesthesia generally lasts a little longer than topical.

Nerve blocks consist of injecting the agent into the region of a nerve trunk or other large nerve branches. This form of anesthesia blocks all impulses to and from the injected nerves.

Spinal anesthesia consists of injecting the agent into the subarachnoid space of the spinal canal

between the third and fourth lumbar space or between the fifth lumbar and first sacral space of the spinal column. This form of anesthesia blocks all impulses to and from the entire area below the point of insertion, provided the patient's position is not changed following injection of the agent. If the patient's position is changed, for example, from dorsal recumbent to Trendelenburg's, the anesthetic agent will move up the spinal column and the level of the anesthesia will also move up. Because of this reaction, care must be exercised in positioning the patient's head and chest above the level of insertion to prevent paralysis (by anesthesia) of the respiratory muscles. In general, spinal anesthesia is considered the safest for most routine major surgery.

Epidural blocks consist of injecting the agent into the epidural space of the spinal canal at any level of the spinal column. The area of anesthesia obtained is similar to that of the subarachnoid spinal method. The epidural method is frequently used when continuous anesthesia is desired for a prolonged period. In these cases, a catheter is inserted into the epidural space through a spinal needle. The needle is removed, but the catheter is left in place. This provides for continuous access to the epidural space.

Saddle blocks consist of injecting the agent into the dural sac at the third and fourth lumbar space. This form of anesthesia blocks all impulses to and from the perineal area of the body.

Caudal blocks consist of injecting the agent into the sacral canal. With this method, anesthesia is obtained from the umbilicus to the toes.

General Anesthesia.-General anesthetics cause total loss of sensation and complete loss of consciousness in the patient. They are administered by inhalation of certain gases or vaporized liquids, intravenous infusion, or rectal induction. The induction of inhalation anesthesia is divided into four stages. These stages and the body's main physiological reaction in each phase are explained below and depicted in figure 2-1.

Stage 1 is called the stage of analgesia or induction. During this period, the patient experiences dizziness, a sense of unreality, and a lessening sensitivity to touch and pain. At this stage, the patient's sense of hearing is increased, and responses to noises are intensified (fig. 2-1).

Stage 2 is the stage of excitement. During this period, there is a variety of reactions involving muscular activity and delirium. At this stage, the vital signs show evidence of physiological stimulation. It is important to remember that during this stage the patient may respond violently to very little stimulation (fig. 2-1).

Stage 3 is called the surgical or operative stage. There are four levels of consciousness (also called planes) to this stage. It is the responsibility of the anesthetist or anesthesiologist to determine which plane is optimal for the procedure. The determination is made according to specific tissue sensitivity of

Figure 2-1.-Stages of anesthesia.

the individual and the surgical site. Each successive plane is achieved by increasing the concentration of the anesthetic agent in the tissue (fig. 2-1).

Stage 4 is called the toxic or danger stage. Obviously, this is never a desired stage of anesthesia. At this point, cardiopulmonary failure and death can occur. Once surgical anesthesia has been obtained, the healthcare provider must exercise care to control the level of anesthesia. The fourth level of consciousness of stage 3 is demonstrated by cardiovascular impairment that results from diaphragmatic paralysis. If this plane is not corrected immediately, stage 4 quickly ensues (fig. 2-1).