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Nurse staffing and ITU complications


In many parts of the world a major problem with health care delivery is capacity - just not having enough hospitals, or doctors, or nurses to do the jobs needed. In the UK we have our own version of this. One way to deal with capacity constraints is to make 'better' use of the staff we have, by using them more 'efficiently'. The quotation marks here signify the difficulty of knowing what is best, and what is most efficient. One of a series of studies on outcomes in intensive care [1] suggests that more "efficient" may not mean better (or even more efficient).


Throughout Maryland information is collected on all patients discharged from the 52 non-federal short-term stay hospitals. Retrospective information was obtained for all patients aged 30 years or older who had abdominal aortic surgery in 1994-1996. At the end of this period all ITU directors were questioned about nurse staffing, with specific questions about the nurse-patient ratio. Information about complications and co-morbid conditions was obtained from the database. Other variables sought were hospital and patient characteristics.


Of the 52 hospitals, 46 performed abdominal aortic surgery, and 38 were able to provide information. Seven hospitals with 478 patients had one nurse to one to three or four patients (fewer nurses per patient) and 31 hospitals with 2128 patients had one nurse to one or two patients (more nurses per patient). The average number of hospital beds and number of abdominal aortic surgery cases was the same for hospitals with more and fewer nurses.

Patients looked after by more or fewer nurses were similar in age, ethnicity, sex, co-morbidity and nature of admission. Slightly fewer were operated on in hospitals with larger numbers of cases of this type, but more were operated on by surgeons performing more of this type of operation. Mortality was similar, but patients in hospital with fewer nurses spent one extra day in intensive care.

Patients looked after in ITUs with more nurses had lower rates of postoperative complications than did those patients looked after in ITUs with fewer nurses (Figure 1). After adjustment for various possible confounders, all the complications in Figure 1 had adjusted relative risks of between 1.5 and 4.5.

Figure 1: Complications after abdominal aortic surgery, by ITU nursing level


Less is more. Fewer nurses may be more efficient according to one definition of efficiency, but it meant more complications and longer patient stay in ITU. One extra day in intensive care per patient adds at least £2,000 to the cost of care of each patient.

The evidence about what makes a quality service is not extensive. From Maryland, other studies have looked at intensive care organisation and outcomes [2], or have taken a wider look at the topic of staffing [3]. Initiatives to improve both safety and value of healthcare in the United States include the Leapfrog group, at , which is worth a visit.


  1. PJ Pronovost et al. Intensive care unit nurse staffing and the risk for complications after abdominal aortic surgery. Effective Clinical Practice 2001 4: 199-206.
  2. PJ Pronovost et al. Organizational characteristics of intensive care units related to outcomes of abdominal aortic surgery. JAMA 1999 281: 1310-1317.
  3. PJ Pronovost et al. Impact of critical care physician workforce for intensive care unit physician staffing. Current Opinion in Critical Care 2001 7: 456-459.
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