Monitoring effectiveness of controlling hospital acquired infections by prevalence surveys

To determine the effectiveness of control measures for hospital acquired infection (HAI) by prevalence studies.

National Hospital of Sri Lanka in Colombo (NHSL).

Two prevalence surveys were undertaken, in October 1994 and in July 1997, after implementing infection control measures. The numbers of patients in the two studies were 2563 and 2865. The subjects were assessed for hospital acquired infection through information obtained from case notes and by discussion with ward nursing and medical staff. The changes in infection control activities during this 3-year period included increasing the number of infection control nurses, educational programs to health care workers at all levels, improvements in disposal of clinical waste, implementing published guidelines for use of antibiotics, cannula-site management and urinary catheter care.

The prevalence of HAI in the hospital decreased significantly (p < 0.0001) from 13.5% in 1994 to 8.7% in 1997. A significant decrease (p < 0.0001) in infection rates was observed in medical wards, but the decrease in surgical wards and the burns unit did not reach statistical significance. The intensive care units showed a weakly significant increase (p < 0.05) of infection rate attributable to the large number of war injured who needed intensive care. The most significant reduction in rates of infection was seen in wound infection (p < 0.001), respiratory infections (p < 0.01) and in cannula site infections (p < 0.001).

Implementation of infection control policies can have a significant impact on the prevalence of HAI, and their effectiveness could be measured by repeated prevalence surveys.