Abstract
To investigate the psychometric characteristics of the modified Freedman Sleep Quality Questionnaire (mFSQQ) to assess sleep in Turkish intensive care unit (ICU) patients. This prospective cross-sectional study was conducted between December 2020 and August 2021 with patients older than 18 years, who stayed in the ICU for ≥ 24 h and were cooperative with a Glasgow Coma Scale score ≥ 10 in medical and surgical ICUs of a university hospital. During the adaptation of the items of the mFSQQ, language, content, and construct validity were examined, and the test–retest method and internal consistency were used to examine its reliability. The content validity index of the questionnaire was 0.82. The Kaiser–Meyer–Olkin measure of sampling adequacy was 0.71, which indicates adequate sampling; Bartlett’s test of sphericity was χ2 = 2868.97, p < 0.001. The Turkish version had three subscales. The factor loadings of the items were above 0.30, and the factors explained 60.59% of the total variance. The test–retest reliability coefficient was 0.85, indicating high consistency. The Cronbach α reliability coefficient was 0.80, indicating high reliability. The item-total correlations were found to be sufficient (between 0.25 and 0.78). The Turkish version of the mFSQQ showed good psychometric characteristics and can be used as a routine evaluation instrument to determine sleep quality by the ICU team and to promote sleep.
Supplementary Information
The online version contains supplementary material available at 10.1007/s41105-022-00389-2.
Keywords: Critical care, Validity, Sleep deprivation
Introduction
Sleep is a dynamic and physiological need for restoring and maintaining health and well-being [1]. Sleep plays a critical role in stress response, emotional regulation, and cognitive functioning [1, 2]. However, sleep disruptions are common in patients followed in the intensive care unit (ICU) and are associated with adverse outcomes such as decreased cognitive functions, increased length of hospital stay, and mortality [3].
More than 60% of intensive care patients report having sleep disruptions during their stay in the ICU [4, 5]. There are several factors responsible for sleep disruptions in intensive care patients. These factors may be related to the ICU settings or the clinical condition of the patient. Alarms, noise, activities of ICU professionals (i.e., physicians, nurses), direct or indirect light, measurement of vital signs, tests, and drug administrations can be considered among the environmental factors that cause sleep disruptions in the ICU [6, 7]. Clinical status of the patient (e.g., organ dysfunction, systemic inflammatory response, pain, and stress) and therapeutic interventions (medications such as vasopressors, antibiotics, sedatives, or analgesics) are other factors that lead to changes in sleep structure [8, 9]. These factors may continue to affect the patients’ sleep quality, even after their discharge. More than half of ICU survivors reported continuing to experience worse, interrupted, or altered sleep patterns for a few months after hospital discharge, compared to their prehospital patterns [10].
Inadequate sleep may cause decreased attention and impaired psychomotor performance and may contribute to the neurocognitive dysfunction common in ICU patients. Mental status changes are more common in ICU patients with severe sleep disruption [11]. Sleep disruptions can also alter the ability to breathe spontaneously and precipitate weaning failure in mechanically ventilated ICU patients. A recent study found altered sleep was associated with prolonged duration of mechanical ventilation and difficult weaning in mechanically ventilated patients [12].
Sleep is critical as a potentially modifiable risk factor that affects both the emotional and physical recovery of ICU patients. Promoting healthy sleep and good sleep quality should be seen as an essential component of the care of ICU patients. Patients' sleep patterns can be monitored, and problems can be resolved using reliable sleep assessment methods. Various objective or subjective tools are available to assess sleep in ICU patients. Objective methods such as polysomnography (PSG) are considered the gold standard for obtaining information about sleep duration and structure. However, its use in the ICU is limited because it is complex, expensive, and time-consuming [13, 14]. The alternative is to evaluate with subjective methods based on questionnaires, which are cheaper. The Richards-Campbell Sleep Questionnaire (RCSQ) and Freedman's Sleep Quality Questionnaire (FSQQ) are the most widely used tools to assess patients' sleep [4, 15]. The FSQQ is a reliable and promising tool that is developed especially for sleep assessment in ICU patients. Unlike the RCSQ, the FSQQ assesses the extent of both night and daytime sleep quality in the ICU, including patients' sleep in the home setting. The FSQQ also provides a focus on the extent to which the environmental factors or activities in the ICU affect sleep. Thus, it facilitates determining the factors that affect sleep and planning for appropriate interventions. The FSQQ has not been adapted to Turkish, although the RCSQ had been previously adapted to Turkish [16]. It is clear that the tool needs further validation by including Turkish patients. Therefore, this study aimed to evaluate the psychometric properties of the Turkish version of the modified FSQQ (mFSQQ) for sleep assessment in ICU patients.
Materials and methods
Design
This study has a prospective cross-sectional design to determine the psychometric properties of the Turkish version of the mFSQQ.
Sample and setting
The study included patients admitted to ICUs of a university teaching hospital in Turkey between December 2020 and August 2021. The ICUs consisted of tertiary adult medical and surgical units for anesthesia, cardiovascular surgery, and general surgery that had a capacity of 15, 10, and 6 beds, respectively. There are more than 1200 medical, surgical, trauma, and cardiovascular surgery applications per year. The type of ICUs is open wards with a nurse/patient ratio of 1:2.
The number of participants is commonly required to be at least five times the number of items in validity-reliability studies [17, 18]; this rule was taken into consideration in determining the sample size. Thus, participation of at least 130 patients was aimed since the mFSQQ has 26 items. Inclusion criteria for the study were as follows: being hospitalized and planned to stay in the ICU for more than 24 h (intubated or not), over the age of 18, cooperative, and with a Glasgow Coma Scale (GCS) score of ≥ 10. Exclusion criteria were as follows: (a) being diagnosed with delirium at admission to the ICU according to the Confusion Assessment Method for the ICU (CAM-ICU), (b) being sedated (< −1) or agitated (> + 1) according to the Richmond Agitation and Sedation Scale (RASS), (c) being hemodynamically unstable, (d) having a medical history of sleep disorder, (e) having neurocognitive dysfunction, (f) having severe auditory or visual impairments, (g) being admitted to ICU more than once, and (h) being transferred from external ICUs.
Data collection procedure
All potential participants were screened for eligibility criteria between 8:00 am and 12:00 am daily by the research nurse along with the head nurse of each ICU. Since each participant must be awake and calm, patient consciousness levels were assessed daily with RASS and GCS. Similarly, the presence of delirium was evaluated using the CAM-ICU.
The data were collected using the Turkish version of the mFSQQ and a patient information form. The patient information form recorded the socio-demographic (age, gender, etc.) and clinical (medical diagnosis, comorbid conditions, APACHE-II score, GCS score, etc.) characteristics of the patients at the time of admission. The FSQQ, which was developed by Freedman et al. (1999), is a tool that subjectively evaluates sleep quality in ICU patients, taking into account the environmental factors in the ICU [4]. Due to the importance of pain in sleep quality in ICU patients, the FSQQ was later modified by Bihari et al. with the addition of pain assessment [19]. The questionnaire requires participants to rate on a 10-point scale their overall quality of sleep (a) at home in the weeks and months before their admission to the ICU, (b) averaged across their whole ICU admission, and (c) on the first day, at the midpoint, and at the end of their ICU stay. Sleep quality is graded from 1 (poor quality) to 10 (excellent quality). Sleepiness is graded from 1 (incapable of keeping awake) to 10 (completely alert and awake). Regarding the environmental factors and noise, a score of 1 indicates “no interruption” and 10 indicates “significant interruption” [4, 19]. The questionnaire were asked on the patients discharge day from the ICU. On average, it took 2–5 min to complete the questionnaire. If there was a problem preventing patients from completing the questionnaire (e.g., muscle weakness, invasive intubation), the questionnaire was read loudly for the patients, and their responses were recorded by writing.
Ethical considerations
The permission to adapt and use the modified version of the questionnaire was obtained from Dr. Bihari via e-mail. The study protocol was reviewed and approved by the Clinical Research Ethics Committee of the School of Medicine of an University (Approval #: 2020-20/20) and the hospital administration. Informed consent was obtained from the patients.
Adaptation stages
Language, content, and construct validity of the Turkish version of the questionnaire were evaluated in the context of the validity studies. First, the questionnaire was translated from English into Turkish by a group of seven (two ICU physicians, three nursing faculty members, and two ICU nurses) who were experts in developing topics and tools for psycholinguistics analysis. The Turkish form of the questionnaire was created by combining separate translations. The Turkish form was then translated back from Turkish to English by an independent linguist who had never seen the original form. The Turkish version was finalized by comparing the statements in the back-translated version with those in the original questionnaire and making changes where necessary. A panel of ten experts, consisting of five ICU physicians and five ICU nurses, evaluated the content validity of the questionnaire using the Davis technique. The experts evaluated the questions in terms of clarity, scientific content, and the measurement and evaluation criteria. They were asked to suggest changes or revisions to the items as needed. Content Validity Index (CVI) was used to evaluate expert opinions. Factor analysis was used for the construct validity of the questionnaire.
The reliability of the questionnaire was evaluated using the test–retest method and internal consistency. The stability of the questionnaire was assessed by the evaluation of the correlation between the questionnaire administered by two observers (researchers) 1 h apart. Intra-class correlation coefficient (ICC) was used for this evaluation. Finally, Cronbach's alpha (α) was used to determine internal consistency.
Analysis
The data were analyzed with the Statistical Package for the Social Sciences (SPSS version 25.0, SPSS Inc., Chicago, USA). Statistical methods used in data analysis are summarized in Table 1. In addition, Bartlett’s test was used for the suitability of the sample for factor analysis, and the Kaiser–Meyer–Olkin (KMO) test was used for the adequacy of the sampling. The statistical significance level was set as p < 0.05.
Table 1.
Methods and analyses used in the evaluation of data
| Descriptive analyzes of the participants | Acceptable values | |
|---|---|---|
| • Socio-demographic and health characteristics of the participants | • Number, percentage, mean, standard deviation | |
| Validity analyses | ||
|
• Language validity • Content validity • Construct validity |
• Translation and back-translation • CVI (Davis technique) • Factor analysis |
• > 0.80 • For KMO index: – 0.90–1.00: excellent sampling – 0.80–0.89: very good sampling – 0.70–0.79: adequate sampling – 0.60–0.69: mediocre sampling – 0.50–0.59: week sampling – < 0.50: inadequate sampling • For factor loads: > 0.30 |
| Reliability analyses | ||
|
• Test–retest method • Internal consistency of the items |
• ICC • Cronbach’s alpha (α), ITC |
• > 0.70 • (α) > 0.70, ITC ≥ 0.20 |
CVI content validity index; ICC intra-class correlation coefficient; ITC item total correlation coefficient
Results
Demographic and health characteristics of the participants
The sample of the study consisted of 132 patients who met the inclusion criteria within the specified date range. The mean age of the patients was 50.92 ± 10.63 years (range: 20–68 years), and most of the patients (59.8%) were men. Most of the patients (40.9%) were hospitalized due to respiratory problems. The majority of the comorbidities of the patients were hypertension (44.7%) and diabetes (22.7%). The mean GCS score of the patients was 12.03 ± 1.55. Mechanical ventilation was required in 35.6% of the patients, and the mean length of ICU stay was 10.21 ± 7.60 days. The socio-demographic and health characteristics of the patients are shown in Table 2.
Table 2.
Socio-demographic and health characteristics of the patients
| Characteristics | Total (n = 132) |
|---|---|
| Age, mean ± SD | 50.92 ± 10.63 |
| Sex, n (%) | |
| Male | 79 (59.8) |
| Female | 53 (40.2) |
| Admission diagnosis, n (%) | |
| Respiratory diseases | 54 (40.9) |
| Infection | 6 (4.5) |
| Trauma | 18 (13.6) |
| Post-operative/surgical monitoring | 33 (25.0) |
| Other medical reasons | 21 (16.0) |
| Comorbiditiesa, n (%) | |
| Diabetes | 30 (22.7) |
| Hypertension | 59 (44.7) |
| Heart failure | 11 (8.3) |
| CVDs | 12 (9.1) |
| COPD | 28 (21.2) |
| Kidney failure | 24 (18.1) |
| Malignancy | 7 (5.3) |
| APACHE-II score, mean ± SD | 14.28 ± 4.96 |
| GCS score, mean ± SD | 12.03 ± 1.55 |
| Requirement for MVb, n (%) | 47 (35.6) |
| ICU length of stay (days), mean ± SD | 10.21 ± 7.60 |
Validity
Content validity
Since most of the ICUs in Turkey do not have a “bedside phone” and “television”, these evaluations included in the sub-headings of the question “Rate how disruptive the following activities were to your sleep during your ICU stay” were removed in line with expert opinions. It was also suggested that the disturbing alarm sounds (heart rate monitor, ventilator, oxygen finger probe, and intravenous pump) mentioned in the survey should be collected under a single item called “alarms”. After these changes, the CVI measured according to the Davis technique was found to be 0.82.
Construct validity
This stage was carried out with the final version of the questionnaire obtained as a result of the content validity analysis. A KMO value of 0.71 and Bartlett's test of sphericity (χ2 = 2868.97, df = 231; p < 0.001) showed satisfactory sample adequacy and supported the applicability of factor analysis by varimax rotational exploratory factor analysis. The Varimax rotation method showed that the questionnaire measured 60.59% of the trait and that it had a three-factor structure (Table 3). The factor loads of the questionnaire varied between 0.47 and 0.84 (Table 4).
Table 3.
Results of the factor analysis
| Varimax rotation sums of squared factor loadings | |||
|---|---|---|---|
| Factor | Total | Explained variance (%) | Cumulative variance (%) |
| 1 | 6.974 | 31.701 | 31.701 |
| 2 | 3.611 | 16.412 | 48.113 |
| 3 | 2.794 | 12.702 | 60.815 |
Kaiser–Meyer–Olkin = 0.71; Bartlett’s test of sphericity: χ2 = 2868.97, df = 231; p < 0.001
Table 4.
Factor loadings of questionnaire
| Items | 1 | 2 | 3 | |
|---|---|---|---|---|
| Factor 1: Sleep quality | ||||
| Rate the overall quality of your sleep at home | 0.518 | |||
| Rate the overall quality of your sleep in the ICU | 0.602 | |||
| Rate the overall quality of your sleep in the ICU on the following nights; first day | 0.478 | |||
| Mid-stay | 0.665 | |||
| End of stay | 0.721 | |||
| Factor 2: daytime sleepiness | ||||
| Rate the overall degree of daytime sleepiness during your ICU stay | 0.534 | |||
| Rate the overall degree of daytime sleepiness during your ICU stay on the following days; first day | 0.651 | |||
| Mid-stay | 0.789 | |||
| End of stay | 0.765 | |||
| Factor 3: Sleep interruptions (environmental or activities related) | ||||
| Pain | 0.633 | |||
| Noise | 0.761 | |||
| Light | 0.805 | |||
| Nursing interventions | 0.680 | |||
| Diagnostic testing | 0.619 | |||
| Vital signs measurement | 0.703 | |||
| Blood samples | 0.761 | |||
| Administration of medicines | 0.789 | |||
| Alarms | 0.836 | |||
| Nebulizer | 0.841 | |||
| Doctors/nurses pagers and phones | 0.663 | |||
| Talking | 0.539 | |||
ICU intensive care unit
Reliability
Test–retest method
The consistency of the results obtained with the Turkish version of the questionnaire was evaluated by comparing the results of the questionnaires administered by different observers. Based on the analysis, the ICC was 0.85 (95% confidence interval (CI): 0.64–0.94; p < 0.05).
Internal consistency and item analysis
According to the internal consistency analysis of the questionnaire items, the reliability coefficient (α) was found to be 0.80. It was found that the item-total correlation coefficients ranged from 0.25 to 0.78 (Table 5).
Table 5.
Item analysis for the questionnaire
| Items | Item-total correlation coefficient | Reliability coefficient when the item is excluded |
|---|---|---|
| 1. Rate the overall quality of your sleep at home | 0.570 | 0.810 |
| 2. Rate the overall quality of your sleep in the ICU | 0.510 | 0.808 |
| 3.1. Rate the overall quality of your sleep in the ICU on the first day | 0.682 | 0.809 |
| 3.2. Rate the overall quality of your sleep in the ICU on the mid-stay | 0.783 | 0.807 |
| 3.3. Rate the overall quality of your sleep in the ICU on the end of stay | 0.616 | 0.808 |
| 4. Rate the overall degree of daytime sleepiness during your ICU stay | 0.751 | 0.808 |
| 5.1. Rate the overall degree of daytime sleepiness during your ICU stay on the first day | 0.683 | 0.806 |
| 5.2. Rate the overall degree of daytime sleepiness during your ICU stay on the mid-stay | 0.761 | 0.807 |
| 5.3. Rate the overall degree of daytime sleepiness during your ICU stay on the end of stay | 0.645 | 0.805 |
| 6. Rate how disruptive the following activities were to you sleep during your ICU stay; | ||
| 6.1. Pain | 0.721 | 0.797 |
| 6.2. Noise | 0.674 | 0.796 |
| 6.3. Light | 0.596 | 0.796 |
| 6.4. Nursing interventions | 0.572 | 0.798 |
| 6.5. Diagnostic testing | 0.789 | 0.795 |
| 6.6. Vital signs measurement | 0.353 | 0.791 |
| 6.7. Blood samples | 0.415 | 0.790 |
| 6.8. Administration of medicines | 0.273 | 0.802 |
| 6.9. Alarms | 0.780 | 0.793 |
| 6.10. Nebulizer | 0.257 | 0.804 |
| 6.11. Doctors/nurses pagers and phones | 0.343 | 0.803 |
| 6.12. Talking | 0.779 | 0.797 |
| Total Cronbach’s alpha: 0.80 |
ICU Intensive care unit
Discussion
There has been an increasing number of studies evaluating sleep quality in the ICU because of increasing concerns with the quality of ICU stay and its impact on the mental, cognitive, and physical health of patients surviving a critical illness [20]. Evidence suggests that sleep disruptions can result in health problems, such as chronic fatigue and decreased immunity, as well as mental health derangement, including a higher risk of delirium, cognitive dysfunction, decreased memory, and irritability [21, 22]. Additionally, proper sleep assessment and sleep promotion are strongly recommended in ABCDEF bundle in critical care [23]. For this reason, sleep quality assessment in the ICU is essential for patient management.
Questionnaires have been developed to assess sleep in ICU patients [4, 15]. Questionnaires allow short- and long-term evaluation of a larger number of patients than does PSG, as well as allowing the implementation of effective interventions to improve sleep quality. The tool studied ‘‘modified Freedman questionnaire’’ assesses the quality of sleep in ICU patients subjectively by taking into account environmental factors. The questionnaire can be easily administered to ICU patients. In a study investigating the factors affecting the sleep quality of 84 ICU patients according to the Freedman questionnaire was reported that the sleep quality of the patients ranged between 4.0 ± 1.7 (p > 0.001) on a 10-point scale, and the most disruptive factor was the measurement of vital signs [24]. This study shows that the Turkish version of the mFSQQ, one of these questionnaires, is supported by acceptable psychometric properties and can be used to assess sleep quality in ICU patients in Turkey (CVI = 0.82 > 0.80; KMO index = 0.71, adequate sampling; factor loads = between 0.47 and 0.84 > 0.30 for all items; ICC = 0.85 > 0.70; Cronbach’s alpha = 0.80 > 0.70; ITC = between 0.25 and 0.78 ≥ 0.20).
In the original study by Freedman et al., in which the questionnaire was developed and used for the first time, the results related to the validity and reliability of the questionnaire were not examined except for factor analysis, and this was stated as a limitation by the researchers [4]. Only one other study had previously investigated the psychometric properties of the FSQQ [25]. Unlike in our study, the CVI was not used, and a different strategy was followed regarding the expert opinion in that study. Based on expert ratings, the questionnaire was reported to have practical and correctly defined items [25]. Similarly, they reported a KMO value of 0.75, indicating that the sampling in their study was also sufficient. However, unlike our study, it was reported that the questionnaire had a four-factor structure in both the original study and the Spanish version (factor 1: sleep interruption secondary to interruptions by the staff or human factor, factor 2: quality of sleep, factor 3: daytime sleepiness, and factor 4: sleep interruption by environmental) [4, 25]. This difference might have resulted from the changes we made in the questionnaire by considering the structure of ICUs in Turkey. Similarly, the study on the Spanish version of the questionnaire reported high ICC (> 0.75 for each item) and cronbach α value (0.93) [25].
In the light of the findings of our study, we believe that Turkish version of mFSQQ will have several applications in the clinical setting. In ICU clinical settings, the mFSQQ could be used as a routine evaluation instrument to distinguish good and poor sleepers and then direct nurses to make corresponding treatment plans. Patients included in the study were more alert and intact. These patients may actually be more bothered by noise and interruptions. Therefore, their sleep may need to be evaluated more regularly than in sedated, unresponsive or unconscious patients. Thus, the brevity and good psychometric properties of the mFSQQ indicate that it is a suitable instrument for this patients. In clinical research, the mFSQQ can be used in correlational studies for the evaluation of sleep quality that may be associated with other variables such as anxiety, stress, ICU stay and life quality.
Strengths and limitations
By including both ventilated and non-ventilated patients in this study, we found that there was no difficulty in using the questionnaire in mechanically ventilated patients who were conscious. We read the questionnaire to these patients more loudly and showed them the questions in a larger font size so that they could point out their answers by hand gestures.
This study has some limitations. To our knowledge, this is the second study to test the relevance of the mFSQQ in another culture and language; therefore, the study was limited in terms of its comparison to other studies. This study was carried out in a single center with few participants because the patients had to be awake and have cognitive capabilities to understand the questions to respond to the questionnaire. Therefore, the results cannot be generalized. Multicenter studies with larger samples are needed to confirm the validity and reliability of the questionnaire. This study was limited to medical and surgical patients. Further studies are needed to assess sleep quality using the questionnaire in more diverse intensive care populations. The study involved some adjustments in the questions of the original mFSQQ since the ICUs where our study was carried out were of open ward type. However, these changes may be disregarded, and the whole questionnaire may be retested in future studies, depending on the ICU setting in which the study will be conducted. Another limitation was the lack of objective sleep measures in this study. The use of PSG could further validate the results related to sleep. However, funding is not available for PSG in many parts of the world. Therefore, although not an option in this study, the use of PSG may be considered for future research.
Conclusions
Based on the results of this study, the mFSQQ demonstrated good psychometric properties and can be used as a reliable tool to assess sleep quality in Turkish ICU patients. This tool can be easily applied by the intensive care team, especially nurses, to diagnose sleep problems of the ICU patients early and identify the factors affecting their sleep. Thus, it may enable nurses to apply nursing interventions to promote healthy and good sleep.
Supplementary Information
Below is the link to the electronic supplementary material.
Author contributions
ÖED: conceptualization, methodology, formal analysis, ınvestigation, resources, data curation, writing—original draft, writing—review and editing, visualization. YY: conceptualization, methodology, data curation, writing—original draft, writing—review and editing, visualization, project administration.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Declarations
Conflict of interest
The authors declare that they have no conflicts of interest.
Ethical considerations
The permission to adapt and use the modified version of the questionnaire was obtained from Dr. Bihari via e-mail. The study protocol was reviewed and approved by the Clinical Research Ethics Committee of the School of Medicine of Uludag University (Approval #: 2020-20/20) and the hospital administration. Informed consent was obtained from the patients.
Footnotes
Publisher's Note
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Change history
11/5/2024
A Correction to this paper has been published: 10.1007/s41105-024-00555-8
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