High patient to nurse ratios may lead to more errors and fatal outcomes.
A high nurse to patient ratio in intensive care units was independently associated with a lower risk of in-hospital death, according to results from a study involving more than a thousand ICUs in 75 countries.
An analysis of data from the EPIC II study showed a nurse to patient ratio of more than 1:1.5 in the ICU was associated with lower in-hospital death compared with a 1:2 ratio (odds ratio 0.71, 95% CI 0.57-0.87, P=0.001), reported Ruth Kleinpell PhD, RN, from Rush University Medical Center in Chicago, and colleagues at the Society of Critical Care Medicine meeting. The results also were published in Critical Care Medicine.
“The study reinforces the importance of having good staffing, especially in the ICU where you have your most critically ill patients,” Kleinpell said.
The Extended Prevalence of Infection in Intensive Care (EPIC II) study in 2007 collected data from ICUs twice in a 24-hour period — once from 10-11 a.m. and again from 10-11 p.m. On the day that the data were collected, 13,696 adults were at 1,265 global ICUs, with the majority located in Western Europe. Other regions participating in the study were North America, Central and South America, and Asia.
About 60% of the participating centers were university hospitals. The overall ICU mortality rate was 18.2%, according to the EPIC II results.
The current study found that participating North American centers were more likely to have 24-hour microbiology availability and a 24-hour emergency department than centers in Africa and Eastern Europe, but they were less likely to have an intermediate care unit. More than 80% of the centers in the study were closed format. ICU volume was lower in participating ICUs from Western Europe, Latin America, and Asia versus North America.
The study also found that medical and mixed ICUs were associated with a higher risk of in-hospital deaths compared with surgical ICUs (OR 1.76, 95% CI 1.47-2.12 and OR 1.54, 95% CI 1.30-1.83, respectively).
Kleinpell, along with Jean-Louis Vincent, MD, PhD, of Erasme Hospital in Brussels, and colleagues said that the increased risk of in-hospital death may have been because the working nurses had limited resources.
“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,” they wrote in the journal article.
ICUs in North America had a nurse to patient ratio of 1:1.5 in the morning, and 1:1.6 in the evening. Nurse to patient ratios were significantly lower in Western Europe and Latin America, which each had an average of 1:1.8. Collectively, all the ICUs analyzed had a 1:1.5 ratio in the morning and a 1:1.8 ratio in the evening.
Brazil had the lowest nurse to patient ratio at 1:2.55 of the participating countries, Kleinpell said. France, Germany, Spain, and Belgium rounded out the top five. The U.S. was 11th out of the countries, with a median of 1.57.
The authors noted that because the study was voluntary, there may have been selection bias. Also data from EPIC II study were collected on a single day so may not have represented other days. The authors also noted that the multivariable analysis may have missed some factors, such as adherence to evidence-based guidelines, quality of care, country-specific practices, level of staff expertise, and disease-specific outcomes.
They cautioned that their data was exploratory and required confirmation through prospective studies “that consider additional country-specific ICU practice variations.”