Patient turnover and nursing staff adequacy

Health Services Research, April, 2006 by Lynn Y. Unruh, Myron D. Fottler

National and statewide assessments of hospital nurse staffing frequently utilize a measure that averages counts of the number of nurses or hours of nursing care given the number of patients or patient days of care per hospital (Aiken, Sochalski, and Anderson 1996; Anderson and Kohn 1996; Spetz 1998; Buerhaus and Staiger 1999; Kovner, Jones, and Gergen 2000; Unruh 2002). These calculations provide a rough measure of nursing staff resources given patient volume, but they do not consider the intensity of nursing care that must be provided for that patient volume.

Intensity of nursing care, or the intensive effort spent at work (Green 2001), is important to consider because staffing needs vary not only with the number of patients being cared for, but also with the type of care provided for each of those patients. As nursing care intensity increases, the amount of nursing staff required to properly care for patients will increase (Moores 1970).

Factors that contribute to the level of intensity include: (1) other human resources, such as support staff; (2) physical resources, such as unit layout; (3) the work design and technology, such as the level of computerization and model of nursing care; (4) administrative practices; (5) the severity of the patients being cared for; and (6) the turnaround time to produce the product (patient turnover or throughput) (Cooper and Zaske 1987; Nichols 1991; Shamian et al. 1994; O'Brien-Pallas et al. 1997; Allan 1998; Cavouras 2002; Seago 2002).

Ideally, a measure of nursing staff adequacy indicates the volume of nurses of a certain skill level that is necessary for the given volume of patients given the intensity of nursing care required for those patients. Measuring intensity directly has been difficult as it involves assessment of mental and physical exertion on a variety of tasks and decision-making processes (O'Brien-Pallas et al. 1997). Indirectly, one could approximate it by using one or more of the factors listed above.

Patient severity is an important factor influencing nursing care intensity that is measurable and has been used to adjust nurse staffing measures (Aiken, Sochalski, and Anderson 1996; Lichtig, Knauf, and Milholland 1999; Spetz 2000; Unruh 2002, 2003a, b). Patient turnover (the inverse of length of stay) is another important measurable factor affecting the intensity of nursing care. As patient turnover increases, a similar amount of nursing care must be delivered in a shorter period of time during each patient stay (Moores 1970; Dellit et al. 2001). Also, as turnover increases, admission, transfer, and discharge procedures, thought to be the most intensive periods of the patient's stay, take up an increasing proportion of the stay (Moores 1970; Jacobson, Seltzer, and Darn 1999; Cavouras 2002; Steinbrook 2002). In general, reduced length of stay is hypothesized to eliminate the lower resource use patient care days, while retaining the higher resource use days (Shamian et al. 1994).

It is not known exactly to what extent increased patient turnover (a shorter length of stay) increases nursing intensity. Improvements in some surgical techniques can lead to patients recovering more quickly from surgery, which may result in less needed nursing care per patient stay. Also, when patients are discharged sooner, they may have nursing care "left over" to be completed postdischarge. However, other types of medical care improvements that reduce the length of stay may result in even greater amounts of needed nursing care, while having nursing care to be performed postdischarge also necessitates a more intensive discharge teaching process. In the absence of direct observation of the nursing process, measures indicating nursing care intensity through a patient turnover indicator such as length of stay can only be preliminary and approximate.

PREVIOUS RESEARCH

Research over a number of years indicates that the inverse of length of stay is an indicator of nursing care intensity. An early paper by Moores (1970) reviews a 1948 British study by Cohen that found a significant inverse relationship between length of stay and the number of trained nurses. Cooper and Zaske (1987) find a strong inverse relationship between pharmacy workload intensity and length of stay. In a 1983 study, length of stay is the most significant predictor of nursing resource use (Caterinicchio and Davies 1983). Shorter (longer) length of stay is related to increased (decreased) nursing hours in several recent studies (Kumarich, Biordi, and Milazzo-Chornick 1990; Shamian et al. 1994; ANA 1997; O'Brian-Pallas et al. 1997).

In a case study using data from a hospital Medicus patient classification system, Graf and associates (2003) find that while average patient length of stay (ALOS) fell around 22 percent from 1993 to 2000, daily nursing workload per patient increased 19 percent. Several studies call for including length of stay in physician or nursing workload measurement systems (Jacobson, Seltzer, and Darn 1999; Lichtig, Knauf and Milholland 1999; Dellit et al. 2001).