Healthcare Quality and Safety

Studies of the Effects of Patient Flow Variability on Healthcare Quality and Safety

Smoothing the Way to High Quality, Safety, and Economy

“Direct and indirect savings from smoother patient flow could give Medicare a new lease on life, underwrite biomedical research, reduce the national debt, support schools, and serve many other private and public purposes. At the same time, properly managed patient flow can reduce medical errors and enhance the quality of care. We owe these improvements to our patients, to the health care community, and to the next generation.” New England Journal of Medicine, October 24, 2013. Learn more »

Nurse Staffing

According to Dr. Harvey V. Fineberg, President of the Institute of Medicine of the National Academies, compassionate care cannot be provided when nurses are overloaded:

“You have to have time to experience the reality of compassion. You cannot always be running to the next”. “A setting that does not permit time, is not going to enable compassion”. Watch video »

Since staffing to peak patient load is no longer possible, hospitals staff to average patient census levels. The result of this staffing approach is frequently understaffing with attendant deterioration in quality and safety. Watch this video to hear Dr. Litvak speak about inadequate hospital nurse staffing »

Attempts to dynamically respond (i.e. staff up) to changes in the patient census have been shown to be unsuccessful. For details of a study of patient flow variability and nurse staffing funded by the Robert Wood Johnson Foundation, click here.

Addressing flow variability is the only solution to minimize nurse-to-patient staffing variability as Litvak and Laskowski-Jones discuss here.

Nurse overload with excessive patient demands leads to higher healthcare-associated infection rates (HAIs) and costs hospitals millions of additional dollars annually published by the American Journal of Infection Control. For more details, click here.

Excessive patient demand for nurses during peaks in hospital census has a significant impact on readmissions.  Each additional patient per nurse in the average nurse’s workload was associated with 7% higher odds of readmission for heart failure, 6% for pneumonia patients, and 9% for myocardial infarction patients. For more details, click here.

Hospitals with better nursing environments and above-average staffing levels were associated with better value (lower mortality with similar costs) compared with hospitals without nursing environment recognition and with below-average staffing, especially for higher-risk patients. These results do not suggest that improving any specific hospital’s nursing environment will necessarily improve its value, but they do show that patients undergoing general surgery at hospitals with better nursing environments generally receive care of higher value. Read more here.

Improvements within hospitals in work environments, nurse staffing, and educational composition of nurses coincide with improvements in quality of care and patient safety. Cross-sectional results closely approximate longitudinal panel results. Read more here.

Physician Staffing

Physicians at hospitals across the country are regularly subjected to highly fluctuating patient demand. Those peaks in demand are mostly artificial in nature and are the result of artificial variability in patient flow introduced by hospital suboptimal schedules of elective admissions. Smoothing those peaks is the only alternative to reducing physician workloads short of hiring more physicians.

Nearly forty percent of hospital-based general practitioners who are responsible for overseeing patients’ care say they experience unsafe patient workloads at least once a month, according to a study in JAMA Internal Medicine. For more details, click here.


Unmanaged variability in patient flow increases readmission risk. Baker et. al. from Johns Hopkins Hospital studied unplanned readmissions to the neurosciences ICU and found that readmissions risk increased dramatically for patients discharged as a result of increased admissions to the ICU. This study shows that expediting discharges is not the right way to manage peaks in admissions; unnecessary peaks in scheduled admissions need to be addressed directly.

Excessive patient demand for nurses during peaks in hospital census has a significant impact on readmissions. Each additional patient per nurse in the average nurse’s workload was associated with 7% higher odds of readmission for heart failure, 6% for pneumonia patients, and 9% for myocardial infarction patients. For more details, click here.

Hospitals with higher nurse staffing had 25 percent lower odds of being penalized compared to otherwise similar hospitals with lower staffing. For more details, click here.

Inpatient Mortality

Inpatient mortality risk has been shown to be significantly associated with nurse staffing levels and hospital overcrowding, both of which are compromised by unnecessary variability in patient flow.

In a study published in JAMA, Aiken, et. al. showed that mortality increases by 7% as the surgical unit nurse-to-patient ratio decreases from 1:4 to 1:5. Mortality continues to increase by 7% until the ratio reaches 1:7, after which it starts to increase exponentially. For more details, click here.

In another study published in NEJM in March 2011, Needleman, et. al. found that mortality risk increases by 2% for every understaffed shift that a patient is exposed to. In addition, the authors found that increased ADT activity has an even greater effect on mortality (4%) than patient census levels. For more details, check here.

Sprivulus et. al. found a linear relationship between mortality and hospital and ED overcrowding. Click here for more details.

Patient Safety

Occurrence of adverse events is often associated with patient flow variability, especially periods of unanticipated peak patient demand.

Increased patient volume has been shown to be related to an increase in patient harm – one study that established this link was published in the American Journal of Medical Quality in 2008.

A study by Jayawardhana, et. al. published in September 2011 linked higher NQF safe practice adoption with higher nurse hours per patient day. Maintaining higher nurse staffing levels is only possible by managing the variability in patient flow.

Boarding and Diversion

Reducing variability in volume of patient admissions has been quoted as one of the top two measures in reducing ED boarding. Lack of actions in addressing this issue may create a need for legislation. For more details, click here.

Artificial variability in patient flow is a major cause of boarding and diversion of patients in the ED as well as in other parts of a hospital such as a post-anesthesia care unit and ICUs.

McManus et. al. studied the demand for a pediatric ICU and found a very high correlation between scheduled admissions and diversion from the ICU. For more details, click here.

ICU bed availability has been shown to have a significant association with ICU admission and patient goals of care for patients experiencing sudden clinical deterioration. Click here for the study by Stelfox et. al. MA commentary by Litvak and Pronovost.

Hospital Overcrowding

Emergency department (ED) crowding continues to be a reoccurring challenge for patients and providers. ED crowding has led to delays in care, increased mortality, poor patient outcomes, reduced access to care, and decreased patient/provider satisfaction. Although the effects of inadequate patient flow are overt in the ED, patient flow issues are systemwide. High hospital occupancy contributes to poor quality of care and access for patients. Scheduled admissions contribute significantly to variability in occupancy. Variation in scheduled admissions (artificial variability) is the root cause of ED overcrowding and delay in care. Here is another example of why IHO approach is proven effective in managing patient flow.

Rapid Response Teams

Rapid response teams may save lives, but many more lives could be saved by providing the right care at the right place and time. One of the main drivers of rapid response team launches is patient placement in inappropriate units, which in turn is a result of artificial variability in patient flow. Click here to read a JAMA article.