Immune Suppression

The incidence of HIV infection has been stable in USA, at approximately 20–30 newly diagnosed infections per 100,000 population per y.

20–25% of HIV infected pts will require surgery.

Major risk factors: Neutropenia, yeast overgrowth, and/or nosocomial colonization of skin and mucosa.

In one study of AIDS pts undergoing intraabdominal surgery, 22.2% 30-d mortality was reported.

Mortality is greatest at the extremes of age.

Greatest source of morbidity and mortality is secondary to infection.

Pneumonia accounts for approximately 40% of all deaths.

Increased incidence of postop pneumonia, wound infection, postop sepsis, respiratory insufficiency, SIRS, and hypotension due to cardiovascular instability.

Increased healing time.

Nosocomial transmission of infection

Interactions with other drugs (IV recreational drugs, antiviral agents)

Transmission of pathogenic drug-resistant strains of microbial agents to medical personnel (e.g., new strains of tuberculosis)

Decreased pulm reserve due to repeated infections

Decreased myocardial reserve secondary to underlying disease and generalized poor health

Translocation of intestinal bacteria due to severe mucositis

Immune suppression can arise from multiple causes, both primary and acquired.

In the intraop period, surgical trauma, anesthetic agents, blood transfusion with or without severe hemorrhage decreases the immune response.

Primary immune deficiency (most are familial).

The very young have immature immune systems.

Aging alters some cellular immune responses.

Acquired:

• Malnutrition, drugs (glucocorticoids, chemotherapy, antiviral), massive burns, or trauma

• Cancers (leukemia, lymphoma, and multiple myeloma)

• Infections (HIV stages 2–4, influenza, sepsis)

• Smoking decreases respiratory defense mechanisms