Elsevier

The Lancet

Volume 361, Issue 9374, 14 June 2003, Pages 2068-2077
The Lancet

Review
Nosocomial infections in adult intensive-care units

https://doi.org/10.1016/S0140-6736(03)13644-6Get rights and content

Summary

Nosocomial infections affect about 30% of patients in intensive-care units and are associated with substantial morbidity and mortality. Several risk factors have been identified, including the use of catheters and other invasive equipment, and certain groups of patients–eg, those with trauma or burns—are recognised as being more susceptible to nosocomial infection than others. Awareness of these factors and adherence to simple preventive measures, such as adequate hand hygiene, can limit the burden of disease. Management of nosocomial infection relies on adequate and appropriate antibiotic therapy, which should be selected after discussion with infectious-disease specialists and adapted as microbiological data become available.

Section snippets

Pathophysiology

The development of nosocomial infection is dependent on two key pathophysiological factors: decreased host defences and colonisation by pathogenic, or potentially pathogenic, bacteria. Although these two factors can arise independently, for infection to result both must be present to some degree.

Decreased host immune defence is common in patients in intensive care, largely because of continuing, concurrent disease processes. Immunosuppression—primarily due to the release of interleukin 10 and

Predisposing factors

The main predisposing factors are associated with either an increased risk of colonisation or with decreased host defence. There is a plethora of studies detailing the risk factors for various types of nosocomial infection in various groups of patients, but predisposing factors can, essentially, be divided into four key groups: those related to underlying health impairment, those related to the acute disease process, and those related to the use of invasive procedures or to other treatment

Epidemiology

The quoted incidence of nosocomial infection varies, according to the setting—ie, the type of hospital or intensive-care unit—the population of patients, and the precise definition used (hospital-acquired, intensive-care unit-acquired, nosocomial pneumonia, VAP). One of the largest databases related to nosocomial infection in intensive care is the EPIC study.” In this 1-day point prevalence study, information was obtained on all patients who occupied a bed in an intensive-care unit over 24 h in

Effect of nosocomial infection

The effect of nosocomial infection in terms of morbidity, mortality, and increased resource use is substantial. Nosocomial infection is associated with an increased length of stay,48, 49, 50, 51 which results in an additional cost of about US$3·5 billion per year,52 without taking into account antibiotic or other therapeutic costs. In a case-control study of 57 patients with catheter-related infection in Spanish intensive-care units, length of stay was increased by about 20 days and infection

Organisms

Any organism can be implicated in nosocomial infection, and many infections are polymicrobial.” Recent years have seen a swing in the pattern of infecting organisms towards gram-positive infections.56 The surveillance and control of pathogens of epidemiologic importance project (SCOPE) data57 revealed that gram-positive cocci were isolated in 64% of 10617 episodes of nosocomial bacteraemia, whereas gram-negative bacilli were isolated in only 27% of cases. The EPIC study” identified the

Respiratory

The respiratory tract is the most common site of nosocomial infection in the intensive care unit. In the EPIC study,” pneumonia accounted for 47% of nosocomial infections, the figure rising to 65% if all respiratory infections were included. Data from the NNIS show that nosocomial pneumonia accounts for 31 % of all nosocomial infections in intensive care units.30 In trauma patients, Papia and colleagues36 reported that lower respiratory tract infection accounted for 28% of infections. Although

General preventive strategies

Prevention has a key part to play in the limitation of nosocomial infection in intensive care units. Many preventive strategies have been suggested, but the most effective remain basic hygiene and care with catheter insertion and maintenance. The hands of health-care workers have been the subject of considerable research over the years, with several studies reporting high rates of contamination with potentially pathogenic organisms,122, 123, 124 and some linking infection to hand carriage by

Future perspectives

I have selected four areas that I see as having a key role if we are to see great and sustained reductions in nosocomial infections in our intensive-care units.

First, the roles of understaffing and staff composition as predisposing factors for nosocomial infection need to be emphasised. Fridkin and colleagues136 noted that the patient-to-nurse ratio was an independent risk factor for catheter-related bloodstream infection in their population of surgical patients in intensive care. The same

Conclusion

Nosocomial infection is a cause of increased morbidity, mortality, and resource expenditure throughout the hospital setting, and particularly in the intensive-care unit. A multidisciplinary approach to prevention that involves the whole intensive-care team, including management, is essential if we are to succeed in preventing nosocomial infections. Awareness of risk factors and attention to simple preventive measures such as hand-hygiene can reduce the incidence and effect of these infections.

Search strategy

We searched MEDLINE, using the following keywords: cross infection, nosocomial infection, hospital-acquired infection, ventilator-associated pneumonia, and healthcare-associated infection. We also searched the bibliographies of all relevant articles. We restricted our search to articles published in English or French, and concerning the adult intensive-care-unit population.

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