A law requiring set nurse-to-patient ratios in intensive care units across a US state has not resulted in anticipated improvements in patient welfare, according to a new study.
The law passed in the state of Massachusetts in 2014 required a 1:1 or 2:1 patient to nurse ratio in intensive care, with hopes that it would boost patient safety and outcomes.
“We did not identify improvements in patient outcomes associated with the state’s nursing requirements”
However, research published in the journal Critical Care Medicine has found the staffing regulations appeared to make little or no difference.
Under the state law, ICUs were required to implement 1:1 or 2:1 ratios based on patient acuity and anticipated care needs.
The ratios – for adult patients admitted to ICU for a day or longer – would be determined with the help of a patient acuity tool and the professional judgement of nurses on the unit in question.
The state’s six “academic ICUs” – in teaching hospitals – were required to comply with the new regulations by the end of March 2016, while all other hospitals had until the end of January 2017.
Researchers from the Beth Israel Deaconess Medical Centre – which is affiliated to Harvard Medical School – compared outcomes for patients in Massachusetts ICUs with 114 similar ICUs nationwide before, during and after the regulations came into force.
“The modest changes in nurse staffing we saw in Massachusetts remained unassociated with changes in hospital mortality”
Lead author Dr Anica Law said they had expected to see improvements in patient outcomes as a result of the staffing regulations, but this was not the case.
“We hypothesized that Massachusetts ICU nurse staffing regulations would result in decreased complications and mortality for critically ill patients when compared with patients admitted to ICUs across the country unaffected by Massachusetts regulations,” she said.
“But we did not identify improvements in patient outcomes associated with the state’s nursing requirements,” noted Dr Law.
The analysis focused on mortality rates at academic ICUs but the team also looked at changes in community hospitals and outcomes for critically ill patients who needed support from a ventilator.
In addition, they looked at a range of complications including catheter-associated urinary tract infections, central line-associated bloodstream infections, hospital-acquired pressure ulcers and falls in which patients were injured.
They found there had been small increases in ICU nurse staffing ratios in Massachusetts following the introduction of the regulations. On average, ratios went from 1.38 patients per nurse to 1.28 patients per nurse.
However, the changes were not significantly higher than in other states where the staffing law was not in force, suggesting the increases in Massachusetts could not be attributed to the legislation.
“Efforts to regulate patient-to-nurse ratios should carefully first consider the extent of the effects on nurse staffing levels”
The risk of mortality and complications in Massachusetts’ ICUs also remained stable after the law was brought in, with no real difference compared with hospitals in other areas.
“Our results suggest that the Massachusetts nursing regulations were not associated with changes in staffing or patient outcomes,” said Dr Law.
“The modest changes in nurse staffing we saw in Massachusetts – approximately one extra nurse per 20-bed ICU per 12-hour shift – remained unassociated with changes in hospital mortality,” she said.
The research team said there were “multiple factors” that could have contributed to the minimal staffing changes and lack of improvements observed in Massachusetts.
These included the fact that staffing levels were adequate before the law was passed or the fact hospitals had “significant leeway” in choosing which acuity tool to use and how it was deployed.
The study’s limitations include the fact the researchers could not separate the impact of mandated patient-to-nurse ratios with using measures of acuity to work out staffing levels.
Other methods for deciding safe staffing levels may have had different results, they suggested.
“It is possible that our findings are the result of suboptimal nursing resource allocation as a result of the acuity tool alone, and that using other methods of nurse staffing distribution may yield different outcomes,” said the researchers.
Source: Beth Israel Deaconess Medical Center
The study did not look at the impact of the regulations on other important measures such as patient and family satisfaction and emotional wellbeing or on the nurses themselves when it came to job satisfaction and their working environment – all of which merits “further investigation”, they said.
Meanwhile, they noted that a longer study period might show legislation had prevented a decrease in nurse staffing levels or helped ensure staffing increased in line with rising patient complexity.
In the meantime, the study team concluded there were clear questions about whether it was cost-effective.
“Given the excess costs of enacting and enforcing statewide legislation to implement acuity-guided ICU nurse staffing, future efforts to regulate patient-to-nurse ratios should carefully first consider the extent of the effects of the mandate on nurse staffing levels,” they said in their study paper.
“In line with previous studies outside of the ICU, our study of ICU nurse staffing adds further evidence suggesting that statewide legislation to mandate nurse staffing strategies may not effectively improve patient outcomes,” they said.