Discussion
Human physiology is arranged to sleep at night and to be awake in the
daytime. This can be evidenced by hormones released in the circadian
rhythm. Among these hormones, melatonin is released during nighttime
sleep, but not during daytime sleep. Sudden changes in melatonin release
can produce a jet-lag-like condition, resulting in a disruption in human
mental health and sleep rhythm. Similarly, the shift system that
requires staying awake at night can affect sleep physiology and many
other hormonal mechanisms. Studies have reported that the night-shift
can be associated with a wide range of negative conditions, from
decreased visual acuity, lack of attention and sleep disorders to
psychiatric comorbidities.
There are many studies on psychiatric disorders associated with
nighttime insomnia. These studies addressed problems such as impaired
sleep physiology, decreased quality of life, depression and anxiety
disorders. However, there is no study literature investigating the
concentration and maintenance of attention in healthcare professionals
in intensive care units and the risks that might otherwise arise for
patients.
The necessity of providing uninterrupted health care services worldwide
requires many healthcare professionals to work in the night-shift
system. It would not be wrong to say that health problems associated
with night-shifts can also be seen in healthcare workers.
As per their duties, healthcare professionals are responsible for
carefully monitoring the vital signs of patients and correcting
potential disorders. These disorders may be respiratory or cardiac
problems that require immediate action. The timely recognition and
correction of these situations is directly related to the ability of
healthcare professionals to collect and maintain their attention.
Indeed, in a study on shift-working nurses, Zion et
al.13 reported poorer results of cognitive function
tests at 3am than at 7am, suggesting that the night-shift caused a
disruption in cognitive functions during night hours. Our study also
reported significantly poor results of the SCWI test in the night-shift
compared to the day-shift. This study has shown that a more regular
circadian rhythm, attention-enhancing activities (visit, patient
relatives visit, patient care, etc.) and a higher concentration of
people in the day-shift than at night-shift, may result in faster
collection of the attention and increased ability to focus due to the
greater number of stimuli. Lack of stimuli and deterioration of sleep
rhythm may result in distraction and loss of vital data that may require
immediate attention. This highlights the patient-related causes of high
mortality in the night-shift, as well as factors associated with
healthcare professionals. As a result, deaths due to health personnel
are among the preventable causes of death.
Studies that prove a decrease in attention level in night-shift workers
also draw attention to the cases of self-injury due to carelessness in
healthcare workers. Niu et al.5 applied the D2 test to
nurses working in 3 shifts (day-, evening-, and night-shift), and
reported an increase in selective error rate and a decrease in attention
level in the night-shift. In this study, there was a day-shift group
including nurses working from 08.00 to 16.00 and a night-shift group
including nurses working from 16.00 until 08.00 on the next day. Given
the longer duration of the night-shift (16 hours), the longer duration
of the night-shift (16 hours), it is suggested that the decrease in the
attention level of workers in the night-shift may be due to longer
periods of work and sleeplessness. The longer duration of the
night-shift in this study shows the potential higher rate of poor
results when compared to the working hours in the studies by Niu et
al.5. SCWI test showed a significant deterioration in
duration, error and correction scores in the night-shift group, which
seems to be consistent with the data of the literature studies.
Apart from the reduction in the attention level, it is also
scientifically possible to predict an increase in the level of fatigue
among night-shift workers. The study by Thompson et
al.14 can be considered as proof of this prediction.
It was reported in this study that performance-based fatigue increased
in those working in the night-shift compared to those in the day-shift.
It should not be ignored that serious risks may arise for both the
patient and the healthcare professionals in case of a decrease in the
level of attention in addition to the increase in fatigue. It should be
remembered that there may be errors in the regulation of treatments, as
well as an increased risk of self-injury in healthcare workers. It can
be argued that the risk of injury to patients or healthcare workers will
be higher for the night-shift group in our study, given the longer
duration of the night-shift in our study (16 hours) compared to the
duration of the night-shift (12 hours) in the study by Thompson et
al.14
The imbalance of melatonin levels are known to be involved in the
etiology of depression15,16. A study of hormonal
changes reported a decrease in melatonin levels and an increase in
inflammatory markers in night-shift workers17,18.
Depending on the imbalance of melatonin levels, a depressive mood
becomes inevitable in the night-shift employees. In our study, a
significant difference in the scores of Hamilton depression scale
between the employees working in the night-shift and day-shift was found
to be compatible with the literature. Although Gumenyuk et al.19reported a disturbance in sleep quality as well as
distraction in night-time healthcare workers, there was no difference
between the groups in our study in terms of the results of PUKI, a test
that assesses sleep quality. The difference between the sleep quality
scores of our study and the study by Gumenyuk et al.19can be attributed to differences in sample size. Gumenyuk et al. used a
total of 28 subjects in two groups.
This study was planned based on the hypothesis that a decrease in
attention levels may have a significant effect on patient mortality.
Literature studies have reported higher mortality rates in nighttime and
weekend shifts in patients hospitalized in intensive care units.
Although the researchers have tried to attribute high mortality rates to
factors such as diagnostic and interventional disruptions, there is an
overlook of the high rate of factors that make it difficult to collect
attention during the weekend and night-shifts. Attention levels can be
negatively affected by factors such as lower concentration of people and
longer shift times during weekend and night-shifts, which is believed to
contribute to an increase in mortality rates. In addition, the lower
number of employees in night and weekend shifts should not be
overlooked. The excessive number of chief nurses, support staff,
clinicians and intensive care physicians during the day-shift causes the
distribution of the burden of patient care. However, we believe that the
absence of support staff in the night-shift, the decrease in the
frequency of intensive care visits by the physician working in multiple
units, and the excess of the number of patients per nurse also
contributes to the reduction of attention by increasing the workload.
This study revealed a significant decrease in the level of attention in
the night-shift compared to the day-shift. We believe that it will be
beneficial to shorten the shift times, to keep the number of patients
per staff at international standards, to set active rest periods and to
plan personnel and hours to reduce the lack of attention observed in the
night shift.