Relationship between nursing workloads and patient safety incidents.

Abstract

To evaluate the relationship between nursing workloads and patient safety incidents in inpatient wards of a general hospital.
A retrospective data analysis was conducted involving the internal medicine wards in a teaching hospital in Japan between July 1st and December 31st, 2006. To assess associations between nursing workloads and patient safety incidents, we analyzed the following: the relationships between the level of patients' dependency and the number of incident reports; and the relationships between the presence of accidental falls and the presence of patients transferred from the intensive care unit to the wards.
Fifty-five nurses worked on the wards (105 beds). The total number of incidents was 142 over the 184 days of this study. There was a positive trend between the number of incidents and the total patient dependency score. The presence of accidental falls in the wards was associated with the presence of transfers from the intensive care unit to the wards (odds ratio 3.14, 95% confidence interval: 1.48, 6.65).
Greater nursing workloads may be related to the higher number of patient safety incidents in inpatient wards of hospitals.

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Journal of Multidisciplinary Healthcare 2010:3 49–54
Journal of Multidisciplinary Healthcare
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Relationship between nursing workloads
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Yuji Nishizaki1
Yasuharu Tokuda2
Ekiko Sato1
Keiko Kato1
Akiko Matsumoto1
Miwako Takekata1
Mineko Terai1
Chitose Watanabe3
Yang Ya Lim1
Sachiko Ohde1
Ryoichi Ishikawa1
1St. Luke’s International Hospital,
Tokyo, Japan; 2Mito Medical Center,
University of Tsukuba, Ibaraki, Japan;
3Saitama City Hospital, Saitama, Japan
Correspondence: Yuji Nishizaki
St. Luke’s International Hospital. 9-1
Akashi-cho, Chuo-ku, Tokyo 104-8560,
Japan
Tel +81 3 3541 5151
Fax +81 3 3544 0649
Email nishiyu77@gmail.com
Objective: To evaluate the relationship between nursing workloads and patient safety incidents
in inpatient wards of a general hospital.
Methods: A retrospective data analysis was conducted involving the internal medicine wards in
a teaching hospital in Japan between July 1st and December 31st, 2006. To assess associations
between nursing workloads and patient safety incidents, we analyzed the following: the
relationships between the level of patients’ dependency and the number of incident reports; and
the relationships between the presence of accidental falls and the presence of patients transferred
from the intensive care unit to the wards.
Results: Fifty-five nurses worked on the wards (105 beds). The total number of incidents
was 142 over the 184 days of this study. There was a positive trend between the number of
incidents and the total patient dependency score. The presence of accidental falls in the wards
was associated with the presence of transfers from the intensive care unit to the wards (odds
ratio 3.14, 95% confidence interval: 1.48, 6.65).
Conclusion: Greater nursing workloads may be related to the higher number of patient safety
incidents in inpatient wards of hospitals.
Keywords: risk management, bed control, incident report, patient dependency, nursing care,
diagnosis and procedure combination
Introduction
In order to reduce overall medical costs, an overhaul of the medical fee scheme was
conducted by the Health, Labour and Welfare Ministry of Japan. As a result of that
overhaul in 2003, they introduced the Diagnosis and Procedure Combination (DPC)
payment system into Japanese hospitals. DPC is a fixed payment system per discharge
diagnosis and procedure which is used for reducing health care expenditures. DPC
is also a system which standardized medical information storage and allowed for
the evaluation of quality of medical care.1 In hospitals which participated in this
new payment system, the hospital stays of patients were forced to be shortened in
order for the hospitals to collect payments; therefore, after introducing this new
policy, nurses in inpatient wards became busier than before, with increased bed
turnovers, including a higher number of transfers of patients from the intensive
care units (ICU) to general medical wards and a shortened average length of patient
hospital stay.2
A work overload situation developed for nurses due to an increasing number of bed
turnovers and patient transfers from ICU because of the introduction of DPC. This may
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be considered to be a factor which is associated with patient
safety incidents, such as accidental falls of inpatients.
Meurier and colleagues reported that the most common
causes of errors were a lack of knowledge or information,
work overload, stressful atmosphere and a lack of support
from senior staff. Work overload is an important factor to
consider for controlling patient safety incidents.3
In ICU areas, Stones and colleagues reported that there
was a relationship between the working condition of nurses
and poor patient outcomes, such as the following: central
line associated bloodstream infections; ventilator-associated
pneumonia; and, 30-day mortality.4 We must focus on nurses’
working conditions and try to control work overload in this
new DPC era.
Accidental falls are critical patient safety incidents for
inpatients because elderly inpatients are very vulnerable
and likely to endure accidental falls. Complications result-
ing from fall injuries are a leading cause of death in older
people.5 Rubenstein and colleauges reported that 25% to 75%
of elderly people who had hip fractures did not recover to
their pre-injury functional status;6 therefore, we must focus
on accidental falls.
Poor working conditions have been associated with
burnout of both nurses and physicians.7 A stressful
atmosphere at work is a major cause of burnout. It was found
to be a dangerous factor in depression and in suicides among
medical health workers.8 We also know shorter sleeping time
due to work overload is a cause of patient safety incidents.9
We must safeguard nurses’ mental health by controlling
working hours and conditions.
We must learn from the prior studies mentioned above.
We must also create methods of assessment of working
conditions for nurses to solve the poor conditions and reduce
the number of patient safety incidents, including accidental
falls. We know useful indicators for assessment of nursing
workload in the ICU area,10 but not for the general wards.
This study therefore aimed to evaluate the relationships
in this new era of the DPC scheme between the level of
patients’ dependency and the number of patient safety
incidents and between the presence of accidental falls and the
presence of patients transferred from the ICU to the wards
at a teaching hospital in Japan. The reason why levels of
patients’ dependency and transfers from ICU were chosen
is that the total dependency score of all patients and the
workloads related to newly incoming patients with critical
illnesses, such as occurs in transfers from an ICU, are likely
to predominate over routine nursing tasks in terms of the
amount of daily work, among nurses in this new era of the
DPC scheme. In addition to incident reporting, the presence
of accidental falls was selected as an indicator of risk man-
agement because of its high frequency and its great impact
on patients’ quality of life and mortality.11,12
Methods
Study setting
This study was conducted at St. Luke’s International
Hospital, Tokyo, Japan. This hospital has 520 inpatient beds,
an emergency department, and an outpatient walk-in clinic,
and it provides primary to tertiary care for about 500,000
people in the Tokyo metropolitan area.
In this hospital, the study was conducted on three internal
medicine wards where about 30 patients were admitted con-
stantly each day in each ward. A total of 55 nurses (21, 15,
and 19 for each ward, respectively) worked, based on a two-shift
system. The hospital met the distribution criteria for the number
of inpatients per nurse (seven patients for one nurse).
Data collection
Incident reports
Between July 1st and December 31st, 2006, information on
incident reports was collected from the safety management com-
mittee of this hospital as a safety measure. The incident reports
were required when there were unintended events that could
have harmed or did harm a patient. The incidents included the
following: procedures; examinations; trouble with intravenous
lines and gastric tubes; medication errors; and, accidental falls.
Over the same period, daily information was also collected
from the safety management committee both on the number of
accidental falls, as another safety measure, and on the number
of transfers from the ICU to the internal medicine wards as yet
another measure of nursing workloads.
Patient dependency score
Patient dependency scoring information incorporating the
degree of nursing care (monitoring and procedures) provided
for these patients was collected from daily nursing reports.
These scores were recorded daily on electronic medical
records by nurses working on the inpatient wards. The scores
consisted of 28 items scored from 0 to 1 or from 0 to 2, as
is shown in Table 1. This scoring system is considered a
useful objective indicator to assess the workloads of ward
nurses in a hospital.13
Ethics approval
We handled delicate observational data, such as clinical incident
report data, so ethical approval was necessary. Ethics approval

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was obtained from the Institutional Review Board of St. Luke’s
International Hospital (Approval Number: 06-235).
Statistical analysis
To assess the relationship between the total score of patients’
dependency and the number of patient safety incidents, we
graphed this data to indicate this relationship clearly.
To assess the relationship between the presence of
accidental falls and the presence of patients transferred from
the intensive care unit to the wards statistically we firstly
described a two-by-two contingency table which consisted of
the presence of accidental falls and the presence of patients
transferred from the ICU to the wards. We secondly evaluated
statistical significance by utilizing chi-square analysis, and
then we calculated the odds ratio (OR) of accidental falls by
patients transferred from ICU.
All statistical analyses were conducted utilizing SAS
Enterprise Guide 4 software (SAS Institute, Cary, NC).
Statistical significance was defined as P  0.05.
Results
There was a total of 142 incidents (57, 47, and 38 for wards
A, B, and C, respectively) on the hospital’s internal medicine
wards over 184 days. The daily mean numbers of incident
reports were 0.31, 0.26, and 0.21 for each ward, respectively.
The total patient dependency scores were 54, 314, 50, 404, and
38, 326 for each ward over 184 days, respectively. The daily
mean total scores were 295, 274, and 208, respectively. Wards
with a higher number of incidents tended to have greater total
patient severity scores. Figure 1 shows this trend.
There was a total of 39 accidental falls (12, 18, and 9 for
wards A, B, and C, respectively) on the hospital’s internal
Table 1 The contents of patient dependency scoring system
A: Monitoring and procedure
1. Wound healing care (0: none, 1: done)
2. Resuscitation (0: none, 1: done)
3. The number of measurement of blood pressure (0: 0–4, 1: more than 5)
4. Measurement the amount of urine output (0: none, 1: done)
5. Respiratory care (0: none, 1: done)
6. Dealing with more than 3 peripheral intravenous line at once (0: none, 1: done)
7. Electrocardiogram monitoring (0: none, 1: done)
8. Infusion pump (0: none, 1: done)
9. Arterial pressure measurement (arterial line) (0: none, 1: done)
10. Micro amount functional infusion pump (0: none, 1: done)
11. Central venous pressure measurement (central venous line) (0: none, 1: done)
12. Mechanical ventilator (0: none, 1: done)
13. Blood infusion or derivatives (0: none, 1: done)
14. Measurement of pulmonary artery pressure (Swan-Ganz catheter) (0: none, 1: done)
15. Specific treatment (CHDF, IABP, ventricular assist device and ICP monitor) (0: none, 1: done)
B: Patients’ situation
16. Order of complete rest on the bed (0: none, 1: done)
17. Lifting an arm up to the level of chest (0: possible, 1: impossible)
18. Roll-over by himself (0: possible, 1: possible with assistant tool, 2: impossible)
19. Standing up (0: possible, 1: impossible)
20. Keeping of sitting position (0: possible, 1: possible with assistance, 2: impossible)
21. Moving from one location to another (0: possible, 1: possible with assistance or possible under monitoring, 2: impossible)
22. Way of transfer (0: without assistance, 1: with assistance including delivering)
23. Oral care by himself (0: possible, 1: impossible)
24. Eating (0: possible, 1: possible with partial assistance, 2: impossible without complete assistance)
25. Changing clothes (0: possible, 1: possible with partial assistance, 2: impossible without complete assistance)
26. Communication ability with other people (0: possible, 1: possible or impossible case-by-case, 2: impossible)
27. Understanding of order about medical care and cure (0: yes, 1: no)
28. Dangerous behavior (0: no, 1: yes)
Abbreviations: IABP, Intra-aortic balloon pump; ICP, intracranial pressure monitor; CHDF, continuos hemodiafiltration.

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medicine wards over 184 days. No more than one accidental
fall a day was observed. There was a total of 69 ICU transfers
(31, 19, and 19 for wards A, B, and C, respectively) to the
hospital’s internal medicine wards over 184 days. No more
than one ICU transfer a day was observed except for one day
which had two ICU transfers. We show basic data of incidents,
patients dependency and transfers from ICU in Table 2.
The results of the accidental falls and ICU transfers were
as follows: the first category, ICU transfer (+) and accidental
fall (+) was 11 days; second category, ICU transfer (+) and
accidental fall (-) was 57 days; third category, ICU transfer
(-) and accidental fall (+) was 28 days; and, fourth category,
ICU transfer (-) and accidental fall (-) was 456 days. We
show this two-by-two contingency table data in Table 3. The
results of chi-square analysis utilizing the above mentioned
two-by-two contingency table was statistically significant
(P = 0.0017). The calculation result of the OR was as follows:
OR 3.14, 95% confidence interval (CI): 1.48, 6.65.
Discussion
The results of the present study indicate that a higher
patients’ dependency score was associated with the occur-
rence of incidents on our internal medicine wards. Since
patient dependency may influence the degree of workload
on wards, a bed controller may need to control workloads
by limiting transfers from the ICU to wards with a greater
dependency score.
The results of the present study also indicate that the
presence of transfers from the ICU could be a risk factor
for accidental falls. Previous studies focused mainly on
patient-related factors as risk factors for accidental falls,
but few studies have evaluated the workloads of ward
nurses as a possible risk factor.14,15 In particular, for acute
care hospitals with the DPC scheme, where the number
of transfers from the ICU is increasing, this result may be
important; moreover, it suggests that a greater number of
falls occurs with a higher number of incoming patients.
0
10000
20000
30000
40000
50000
60000
38 incidents
Total
score
57 incidents47 incidents
Figure 1 The association between the number of incidents and total scores of dependency of patients.
Table 2 The basic date of incidents, patients dependency and transfers from ICU
Ward AWard BWard C Total
Total patients dependency score (/184 days)543145040438326143044
Average patients dependency dairy score (/day)295274208777
Total incident number (/184 days)57 4738142
Average dairy incident number (/day) 0.310.260.21 0.78
Total accidental fall number (/184 days) 12 189 39
Average dairy acidental fall number (/day)0.0650.0980.0490.212
Total number of transfers from ICU (/184 days)31 1919 69
Average dairy number of transfer from ICU (/day)0.1680.0160.0160.20
Abbreviation: ICU, intensive care unit.

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The combined use of the number of transfers and the level
of patient dependency may be helpful tools for bed control.
Considering these will facilitate decision-making for the
allocation of emergency admissions to wards to enable the
safe management of patients.
In addition, the preceding study showed a positive
correlation between the overwork level and the mental
health of medical workers.9 Thus, controlling overworking
could prevent incidents and could lead to the restoration
of ward nurses’ mental health; therefore, for both patient
safety and nurses’ mental health on wards, it is important to
appropriately control the workload levels of ward nurses.
The present study had several limitations. Firstly, the ages
and job titles of nurses, which may also be influencing the
number of incidents and their mental health status were not
considered. Secondly, although the number of patients may
be a possible risk factor for incidents, the number of patients
was not considered; thus, the relationship between the
number of patients and incidents was not evaluated. Fourthly,
there might have been a selection bias. We conducted
our study in only three internal medicine wards. A study
involving all wards may be needed to minimize selection
bias. Incident reports are self reported, so there might be a
discrepancy between the submission rate between wards.
Finally, since our study was based on only three wards of a
single hospital and had an observational design, the results
may not be generalizable. A larger prospective study, as well
as a study with an interventional design, will be needed to
further validate these results.
Safe patient management is a very important issue for
establishing trusting relationships between patients, their
families and healthcare providers. This is also related to lower
medical costs.16,17 Although several theories and methods
have been proffered to prevent incidents,18–22 some of them
are not easily understandable nor applicable. Easily available
quantitative indicators, such as the patient severity scores in
our study, appear to be useful for managing patient safety by
monitoring real-time workloads on hospital wards.
Preventing incidents is also likely to lead to better
mental health among nurses working on wards; however,
since our conclusion was based on observational data
in a single hospital, further study is needed to validate
the results. We may need to consider instituting systems
solutions for creating a better working environment for
nurses. By achieving this, we could reduce the number
of patient safety incidents, falls, and nurses’ burnout,
especially in the era of the DPC and the new medical fee
scheme in Japan.
Disclosures
The authors report no conflicts of interest in this work.
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Table 3 Two-by-two contingency table of relationship between
ICU transfer and accidental fall
Accidental fall (+)
11 (days)
Accidental fall (-)
57 (days)
ICU transfer (+)
ICU transfer (-)
28 (days)456 (days)
Abbreviation: ICU, intensive care unit.