Pre-operative clinical assessment for anaesthesia and the effect of HIV infection

HIV infection is common in South Africa, often remaining clinically latent and liable to be missed during clinical pre-operative assessment, despite the patient having a severe degree of immune compromise.

The primary objective was to determine the pre-operative physical status of patients presenting for anaesthesia, and to compare this with subsequent HIV tests and the CD4 counts of the HIV-positive patients. The secondary objective was to determine the prevalence of HIV infection in this group and in selected subgroups.

A sample of 350 adult patients presenting for anaesthesia at Chris Hani Baragwanath Hospital were interviewed pre-operatively, examined, and their American Society of Anesthesiologists physical status grading determined. In those who were confirmed HIV positive by blood sample, a CD4 count was checked. Further data were collected to determine trends in the characteristics of HIV-positive patients.

HIV-positive patients were more likely to be classified as ASA 1 or 2 than ASA 3 or 4 (odds ratio (OR) 2.1). HIV-positive patients with CD4 counts >200 cells/microl were more likely to be ASA 1 or 2 (OR 3.88). Of HIV-positive patients with CD4 counts <200 cells/microl, significantly more were classified as ASA 1 or 2 than ASA 3 or 4 (p < 0.0001). Three patients with CD4 counts <50 cells/microl were classified as ASA 1 or 2. The overall prevalence of HIV infection was 29.4%. Females, patients presenting for obstetric surgery, and younger age groups had higher disease prevalence rates. Patients aged 30 - 39 years (43.0%) had the highest prevalence of HIV infection; the lowest was in patients aged 60 years or older (7.7%).

Routine clinical pre-operative assessment in patients from a population with a high HIV prevalence rate may result in asymptomatic, severe immune compromise being missed in a significant number of patients.