Evaluación Preanestesica

Anesthesia evaluation refers to the series of interviews, physical examinations, and laboratory tests that are generally used in North America and western Europe to assess the general fitness of patients scheduled for surgery and to determine the need for special precautions or additional testing. There is no universally accepted definition of anesthesia evaluation as of 2003; however, the Task Force on Preanesthesia Evaluation of the American Society of Anesthesiologists (ASA) has tentatively defined it as "....the process of clinical assessment that precedes the delivery of anesthesia care for surgery and for non-surgical procedures." Anesthesia evaluation is usually discussed in the context of elective or scheduled surgical procedures rather than emergency surgery .

Anesthesia evaluation is a relatively recent development in preoperative patient care. Prior to the 1970s, anesthesiologists were often given only brief notes or outlines of the patient's history and physical examination written by the operating surgeon or the patient's internist. This approach became increasingly unsatisfactory as the practice of anesthesiology became more complex. In the last four decades, the introduction of new anesthetics and other medications, laser-assisted surgical procedures, increasingly sophisticated monitoring equipment, and new discoveries in molecular biochemistry and genetics have made the anesthesiologist's role more demanding. During the 1980s and 1990s, some departments of anesthesiology in large urban medical centers and major university teaching hospitals began to set up separate clinics for anesthesia evaluation in order to improve the assessment of patients before surgery.

Purpose

Anesthesia evaluation has several different purposes. The information that is obtained during the evaluation may be used to:

• Guide the selection of anesthetics and other medications to be used during surgery.

• Plan for the patient's postoperative recovery and pain management.

• Educate the patient about the operation itself, the possible outcomes, and self-care during recovery at home.

• Determine the need for additional staff during or after surgery.

• Minimize confusion caused by rescheduling operations because of last-minute discoveries about patients' health.

• Improve patient safety and quality of care by collecting data for later review and analysis. The ASA has noted that few controlled trials of different approaches to anesthesia evaluation have been conducted as of 2003, and that further research is needed.

Description

There are several parts or stages in a typical anesthesia evaluation. The evaluation itself may be done in the hospital where the operation is scheduled, or in a separate facility attached to the hospital. The timing of the evaluation is affected by two major variables: the invasiveness of the operation to be performed and the patient's overall physical condition. An invasive operation or procedure is one that requires the surgeon to insert a needle, catheter, or instrument into the body or a part of the body. Surgical procedures are classified as high, medium, or low in invasiveness. Procedures that involve opening the chest, abdomen, or skull are usually considered highly invasive. Examples of less invasive procedures would include tooth extraction , most forms of cosmetic surgery, and operations on the hands and feet.

The patient's physical condition is classified according to the ASA's six-point system as follows:

• P1. Normal healthy patient.

• P2. Patient with mild systemic disease.

• P3. Patient with severe systemic disease.

• P4. Patient with severe systemic disease that is life-threatening.

• P5. Moribund (dying) patient who is not expected to survive without an operation.

• P6. Brain-dead patient whose organs are being removed for donation.

As of 2003, the ASA recommends that patients with severe disease be interviewed and have their physical examination before the day of surgery. Patients in good health or with mild systemic disease who are scheduled for a highly invasive procedure should also be interviewed and examined before the day of surgery. Patients in categories P1 and P2 who are scheduled for low- or medium-invasive procedures may be evaluated on the day of surgery or before it.

Patient history and records

The first part of an anesthesia evaluation is the anesthesiologist's review of the patient's medical history and records. This review allows the anesthesiologist to evaluate the patient for risk factors that may increase the patient's sensitivity to the sedatives or other medications given before and during the operation; increase the danger of complications related to heart function and breathing; and increase the difficulty of treating such complications.

These risk factors may include:

• Heart or lung disease. These diseases often require the anesthesiologist to lower the dosages of sedatives and pain-control medications.

• Liver or kidney disease. Disorders of these organs often slow down the rate of medication clearance from the patient's body.

• Present prescription medications. These may interact with the sedatives given before the operation or with the anesthetic agent.

• Herbal preparations and other alternative medicines. Some herbal preparations, particularly those taken for insomnia or anxiety (St. John's wort, valerian, kava kava) may intensify the effects of anesthetics. Others, like ginseng or gingko biloba, may affect blood pressure or blood clotting. It is important for patients to include alternative health products in the list of medications

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