May 062015

The fewer patients an ICU nurse has to juggle, the better those patients’ chances of making it out of the hospital alive, according to a large observational study published in Critical Care Medicine.

Data from the large EPIC II study suggested that two patients per nurse may be too many for safe, high-quality critical care. Nurse-to-patient ratios above 1:1.5 (meaning fewer than 3 patients per 2 nurses, on average) were independently associated with a lower risk for death (odds ratio of 0.71) compared to when each nurse cared for 2 patients.

The Extended Prevalence of Infection in Intensive Care (EPIC II) study in 2007 collected data from more than 1,200 ICUs in 75 countries (most in Europe and North America), twice a day, at 10 am and 10 pm. More than half were university teaching hospitals; ICU mortality was 18%.

In the U.S. and Canada, the nurse-to-patient ratio stayed close to 1:1.5 at both time points. Western Europe and Latin America had lower nurse staffing, especially at night, with an overall ratio of ~1:1.8.

But the U.S. hardly led the field in ICU nursing staffing, coming in behind most of Eastern Europe and Asia (which approached a 1:1 nurse to patient ratio overall).

"Time constraints related to a reduced nurse to patient ratio may increase the likelihood of mistakes by creating a stressful environment with distractions and interruptions that adversely affect quality of care,” authors hypothesized. Reporting was voluntary, so authors also warned of selection bias.

The finding is statistically robust, but it's still hard to draw conclusions across different national health systems. For example, in many countries outside the U.S., nurses perform the duties of a respiratory therapist.

The study correlates with many previous studies showing a strong link between increased nursing staffing in the ICU and reduced mortality. Most of these were retrospective reviews; the EPIC II study is the largest prospective observational study done to date.

Nurse staffing in ICUs is constrained in the U.S. by supply (not enough nurses), but is mainly a financial decision on the part of hospital administrators. Increasing the nurse-to-patient ratio from 1:2 to 1:1.5 would mean increasing staffing by 33%. In a 20 bed ICU with nurses making about $30/hour, that's about $1-2 million a year -- a relative bargain. This would happen if administrators sensed the public are attuned to the issue, in which case hospitals would start to compete on ICU nursing ratios the same way they do today to buy and promote the latest unproven gadgets.

If you're an ICU nurse, know that (if this data represents reality) your time and attention may be the most precious and powerful lifesaving resource we have in the ICU. Are you consistently assigned to care for 2 patients? Print out the article and this review, and organize with your colleagues to pressure your bosses for increased ICU nurse staffing. You're not lazy -- you're a strong advocate for patient safety.

Read more:

Yasser Sakr et al. The Impact of Hospital and ICU Organizational Factors on Outcome in Critically Ill Patients: Results From the Extended Prevalence of Infection in Intensive Care Study.  Critical Care Medicine, March 2015 • Volume 43 • Number 3.

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