

 Table of Contents  
Year : 2019  |  Volume : 10  |  Issue : 1  |  Page : 1-7

A comparative study of the quality of sleep in patients in the ward: Pre and postsurgery in a tertiary care hospital in South India

1 Department of Psychiatry, JSS Medical College and Hospital, Mysore, Karnataka, India
2 Department of Psychiatry, St. John's National Academy of Health Sciences, St. John's Medical College and Hospital, Bengaluru, Karnataka, India
3 Department of Community Medicine, MVJ Medical College and Research Hospital, Bengaluru, Karnataka, India

Date of Web Publication29-May-2019

Correspondence Address:
Dr. Suhas Chandran
Department of Psychiatry, St. John's National Academy of Health Sciences, St. John's Medical College and Hospital, Sarjapur Road, Bengaluru - 560 034, Karnataka
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mjmsr.mjmsr_37_18

Rights and Permissions

Background: Sleep deprivation has a deleterious effect on recovery in postoperative patients as it can lead to potentially dangerous side effects. The stress of poor sleep along with surgical stress can lead to increased sympathetic activity, which causes increase in catabolic processes, wakefulness, postoperative fatigue, hemodynamic instability, and neurological dysfunction, all of which will adversely affect postoperative recovery of patients. Aims and Objectives: (i) To compare the quality of sleep in patients, pre and postsurgery. (ii) To identify factors causing postoperative sleep disturbance. (iii) To discuss management strategies for improving postoperative sleep quality in surgical patients. Materials and Methods: The study included sixty patients admitted in the general surgical ward, with participants selected by convenience sampling. The Pittsburgh Sleep Quality Index was used to assess pre- and post-operative sleep quality and scores were compared to assess various components of sleep. Comparisons were also drawn with respect to difference in sleep according to age, sex, type of anesthesia administered, history of past use of sleep medications, and room type. Results and Conclusion: Our study showed poor postoperative sleep quality across all subgroups, i.e., age, sex, use of sleep medications, type of anesthesia administered, and room type. During the postoperative period, subjective sleep quality, sleep latency, and sleep disturbance worsened along with reduced duration of sleep, without significant changes in the habitual sleep efficiency and day-time dysfunction. Sleep is an extremely important physiological requirement for recovery after surgical stress. By identifying which component of sleep is being affected more than others, targeted interventions can be designed by the way of pharmacological or non-pharmacological methods to effectively combat sleep disturbance in surgical patients.

Keywords: Postoperative sleep quality, postsurgical insomnia, sleep disturbance

How to cite this article:
Prakrithi S N, Chandran S, Kishor M, Pradeep T S. A comparative study of the quality of sleep in patients in the ward: Pre and postsurgery in a tertiary care hospital in South India. Muller J Med Sci Res 2019;10:1-7

How to cite this URL:
Prakrithi S N, Chandran S, Kishor M, Pradeep T S. A comparative study of the quality of sleep in patients in the ward: Pre and postsurgery in a tertiary care hospital in South India. Muller J Med Sci Res [serial online] 2019 [cited 2020 Jan 18];10:1-7. Available from: http://www.mjmsr.net/text.asp?2019/10/1/1/259251

  Introduction Top

Sleep is a reversible behavioral state of perceptual disengagement and unresponsiveness to the environment.[1] It is one of the most important physiological processes required to maintain the physical and mental well-being of an individual, and the amount of sleep required per day varies from person to person. Sleep deprivation is defined as a prolonged period without the usual amount of sleep or a sufficient lack of restorative sleep over a cumulative period so as to cause physical or psychiatric symptoms and affect routine performance of tasks.[2],[3] Sleep deprivation is a major problem in surgical patients having a deleterious effect on postoperative recovery, which is further complicated by the presence of surgical stress response. The surgical stress response comprises of various endocrine and metabolic changes which occur in the body due to injury. The afferent neurons at the site of injury are activated and their firing impulses result in the release of various cytokines such as interleukin-1 (IL-1) and tumor necrosis factor-alpha from activated macrophages and monocytes in the damaged tissues, which subsequently cause the release of IL-6, which, in turn, is responsible for the acute-phase response. There is activation of the hypothalamic–pituitary–adrenal axis resulting in increased sympathetic activity and tissue breakdown, leading to increased catabolic and reduced anabolic processes.[4] This excessive sympathetic activity also causes an increase in alertness and wakefulness, contributing further to postoperative sleep disturbance.[5] Various factors such as postoperative pain, discomfort due to medical devices, positioning of the patient in bed, and external factors such as noise and light in the hospital ward may lead to disturbed sleep during the postoperative period.[6],[7] This, in turn, can cause excessive fatigue, hemodynamic instability, and hypoxemia.[8],[9] Neurological dysfunction, leading to altered mental status; cognitive dysfunctions; and psychological changes such as increased irritability, anxiety, and depressive symptoms also occur as a consequence of disturbed sleep.[10],[11],[12]

Additionally, poor sleep has also been reported to cause immunosuppression and abnormal immune responses. During sleep, there is reduced activity of the sympathetic nervous system and the hypothalamic–pituitary–adrenal system, which results in the reduction of circulating levels of cortisol, epinephrine, and norepinephrine in the body, which act as immunosuppressants. Furthermore, there is increase in growth hormone, prolactin, and melatonin, all of which are known to increase immune cell activation and production of cytokines. Therefore, with sleep deprivation, there is an increase in immunosuppressant substances and decrease in immune cell activation, causing reduced immunity, thereby predisposing the individual to the development of infections.[13] This makes correcting sleep disturbance in postoperative patients all the more important, as they are already at a higher risk for surgical-site infections, nosocomial infections, and sepsis. Considering the implications, there is a definite need to identify factors contributing to poor sleep quality in surgical patients and provide the necessary interventions to improve sleep so as to reduce the additional stress caused by sleep deprivation, thereby resulting in better postoperative recovery and also improving the patient's subjective sleep quality. Hence, with this background, we started the study with the objectives to compare the quality of sleep in patients pre- and post-operatively and to identify the factors responsible for postsurgical sleep disturbance.

  Materials and Methods Top

The present study was a cross-sectional hospital-based study conducted at a tertiary care center in South India. The study sample consisted of sixty patients who were admitted to the general surgical ward. The participants were chosen based on convenience sampling, and the study was conducted over a period of 4 months, from November 2017 to February 2018. Patients admitted in the general surgical ward, aged 18 years and above, were included in the study. Patients admitted to the intensive care units; patients who had undergone multiple surgeries in the past 3 months; and patients with a history of any primary psychiatric illnesses such as primary insomnias, parasomnias, and dyssomnias were excluded from the study. Each patient selected was then explained about the study, and informed consent was taken before data collection. Approval was taken from the institution's Ethics Committee. Data were collected by interview technique, using a pretested semi-structured questionnaire called the Pittsburgh Sleep Quality Index (PSQI) to assess the quality of sleep. The PSQI assesses the participant's perception of global habitual sleep quality and disturbances retrospectively over a 1-month period. There are 19 items in the questionnaire, which are summed up into the following seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and day-time dysfunction. The global score from these components ranges from 0 to 21 points, where lower scores represent a better sleep quality. A global score of 5 or greater is indicative of poor sleep quality.[14]

Baseline evaluation was done for all those who fitted the inclusion criteria by applying the PSQI scale preoperatively in order to gain knowledge about the patient's usual sleeping habits and the history of use of sleep medication. The participants were then called for interview 1 month postoperatively, when the PSQI was applied for re-evaluation, to assess the amount of sleep quality after surgery. The scores thus obtained were used to compare the quality of sleep and its various components, pre- and post-operatively. Patients who scored 5 or greater on the PSQI were considered to have poor sleep quality and a score of <5 was considered to denote adequate sleep quality. The effect of surgery on the different components of sleep quality according to the PSQI scale was also evaluated by comparing changes in the individual scores which occurred pre- and post-operatively. Analysis was done using SPSS software version 22 statistics for Windows (IBM Corp., Armonk, NY, USA). Descriptive statistics such as percentage were applied and inferential statistics such as paired t-test were applied for the comparison of pre- and post-operative scores, and statistical significance was defined with P = 0.05.

  Results Top

Around 30% of the study participants were under 35 years of age, 48.3% were aged 36–60 years, and 21.7% were aged above 60 years. Nearly 58.3% of them were male and 41.7% were female. Almost 60% of the study participants opted for the general ward, 25% for the four-sharing ward, 11.7% for the two-sharing ward, and 3.3% for the single-bed private ward. Nearly 60% of the patients were operated under spinal anesthesia, 31.7% under general anesthesia (GA), and 8.3% under local anesthesia [Table 1].
Table 1: Distribution of study participants according to various factors

Click here to view

Around 53.25% of the patients aged >60 years reported a poor sleep quality as compared to 35.4% of patients aged between 36 and 60 years and 16.5% of those aged <35 years. The number of females with poor baseline sleep quality was slightly higher than the males, with 36% females and 31.43% males reporting poor sleep quality. The proportion of patients who had poor sleep quality with a history of use of sleep medication in the past was more than that of patients who had not used sleep medication, with 72.73% who had used sleep medications reporting poor sleep and 27.27% of patients who had not taken sleep medication reporting poor sleep. Almost 50% of the patients in the general ward had poor sleep, as compared to 13.33% in four-sharing ward type and none in either two-sharing or single-type rooms [Table 2].
Table 2: Distribution of study participants according to preoperative quality of sleep based on age, sex, past use of sleep medication, and room type

Click here to view

Around 55.56% of the patients aged <35 years, 72.41% of 35–60 year olds, and 69.23% of patients aged >60 years reported worsening of sleep quality postoperatively. Nearly 77.1% of males and 52% of the female participants had a poorer sleep quality (scored higher on the postoperative PSQI). Almost 72.73% of the patients with a history of use of sleep medication and 65.31% of the patients with no such history reported poor sleep. Nearly 89.5% of the patients who were given GA had a poorer sleep quality postoperatively compared to 58.3% of patients of spinal anesthesia and 40% of patients of local anesthesia who reported the same. Postoperative sleep disturbance was reported across all types of wards, with 50% patients in single rooms, 42.86% in two-sharing ward type, 46.67% in four-sharing ward type, and 80.56% in the general ward reporting poor sleep quality [Table 3].
Table 3: Distribution of postoperative sleep quality based on age, sex, type of anesthesia administered, and room type

Click here to view

When we compared each of the component scores of the PSQI scale obtained in the pre- and post-operative periods, we found that during the postoperative period, subjective sleep quality was poor (P< 0.001), sleep latency increased (P< 0.001), sleep duration reduced (P = 0.005), and sleep disturbance increased (P< 0.001). However, habitual sleep efficiency did not vary remarkably in the pre- and post-operative periods (P = 0.051). There was also no significant postoperative change in the sleep quality with respect to the use of sleep medications in the past (P = 0.23). Moreover, it was found that there were no pronounced changes in day-time dysfunction in the postoperative period (P = 0.06) [Table 4].
Table 4: Assessment of changes in the different components of sleep quality pre- and post-operatively

Click here to view

  Discussion Top

The present study included sixty participants, with the majority being middle aged, i.e., within 36–60 years, with 58% of them being males. The aim of the study was to compare the quality of sleep pre- and post-operatively based on various factors and to compare the changes which occurred in different components of sleep pre- and post-operatively. This study showed that, after the surgical intervention, there was significant worsening of subjective sleep quality (the individual's own perception about the quality of his/her own sleep), increase in the sleep latency (the time taken to fall asleep after getting into bed), reduction in the sleep duration (the time in hours the individual actually spends in sleep), and increase in the sleep disturbance (evinced by how often the individual had trouble sleeping because of having pain/discomfort/bad dreams/getting up to use the bathroom). However, there was no significant change in the habitual sleep efficiency (the percentage of time in bed during which the person is asleep) and day-time dysfunction (evidenced by having had trouble staying awake during the daytime, while driving or eating meals or engaging in social activity, besides feeling unenthusiastic about getting things done).

Comparing the global PSQI scores pre- and post-operatively in different patient groups in our study, i.e., age, sex, type of anesthesia, past use of sleep medications, and room type, there was worsening of global sleep quality across all groups postoperatively. There were no significant intergroup variations (i.e., among different age groups or sexes) with respect to change in postoperative sleep quality in this study. Similar results were reported by Beliaev et al., who assessed postoperative insomnia by using questionnaires on time taken to fall asleep, duration of sleep, night-time awakenings, and other characteristics, with the study showing increased sleep latency (>30 min in 50% of the patients), reduced sleep duration, and increased sleep disturbance in postoperative patients.[15]

Our study did not show statistically significant changes in the postoperative sleep quality with respect to the history of taking sleep medications in the past. However, it is a well-known fact that benzodiazepines (BZDs) can alter sleep architecture. According to Eisen et al., BZDs reduce the duration of rapid eye movement (REM) sleep and slow-wave sleep and increase the duration of Stage 2 sleep.[16] Therefore, the patient does not enter the stages of deep sleep at all, resulting in the feeling of not being adequately rested even after sleeping for a longer duration. Research shows that around 30% of medical and 85% of the surgical patients receive sedative drugs during hospitalization,[17] and these drugs can contribute significantly to postoperative sleep disturbance. Newer “z-drugs” such as zopiclone and zolpidem have a lesser degree of effect on alteration of sleep architecture and patients are also less likely to develop tolerance or dependence to these drugs, compared to older BZDs. Therefore, the newer drugs can be used instead to reduce the amount of variation in normal sleep architecture, possibly improving postoperative sleep quality.

Although the present study did not find a significant increase in day-time sleepiness or dysfunction in the postoperative period in our study, studies conducted by Dolan et al. and Gogenur et al. show that there can be alteration in the circadian rhythm postoperatively and reported increased day-time sleepiness in postoperative patients.[6],[18] In a study investigating circadian distribution of sleep phases after major abdominal surgery, significantly increased REM sleep and increased day-time sleepiness were noted after surgery compared to before surgery, providing further evidence that the circadian rhythm gets disrupted postoperatively.[19]

Our study did not show significant variation in the occurrence of postoperative sleep disturbance in different age groups, but according to another study conducted by Leardi et al., who investigated postoperative sleep disturbance in older individuals, older age had significant impairment of sleep postoperatively compared to younger individuals. This was attributed to impaired melatonin rhythm in older patients.[20]

Although our study did not show significant variation in sleep quality with respect to the type of anesthesia administered, Desborough states that regional anesthesia can inhibit the stress response to surgery and can therefore improve the postoperative outcome.[4] Therefore, using regional anesthesia rather than general anesthesia wherever feasible might perhaps benefit the postoperative recovery. In addition to the type of anesthesia used, the kind of surgery performed and the resulting surgical stress response have a major role in worsening postoperative sleep quality, as the surgical stress response brings about various endocrine and metabolic changes which increase the sympathetic activity, which in turn causes wakefulness. Kain and Caldwell-Andrews compared the sleeping characteristics of adults undergoing outpatient elective surgery with a community control group and reported that the surgical patients experienced significant sleep disturbances postoperatively, increased pain, increased true-wake-time postoperatively, and more night time awakenings >5 min, but not more overall night-time awakenings. The study also reported that, within the surgery group, those who had higher state of anxiety preoperatively had more difficulty sleeping over the monitoring period.[21] Tranmer et al. reported that surgical patients had more sleep disturbance, less effective sleep, and more need for sleep supplementation than medical patients admitted in the same hospital, possibly due to the surgical stress response in these patients, increasing sleep disturbance.[22] Yasuma and Okada examined the prevalence of insomnia complicated by surgical stress by doing a questionnaire survey of fifty adult surgical patients and found that the incidence of insomnias such as early awakenings and difficulty in initiating and maintaining sleep, which was higher on the day of surgery and 1 day after surgery compared to two nights before surgery, suggesting that sleep quality was worsened by surgical stress.[23] Furthermore, a study comparing postoperative sleep in patients of laparoscopic and open cholecystectomy noted that disturbance of sleep architecture, day-time sleepiness, and increased total sleep time were more for open than for laparoscopic cholecystectomy, in that the disturbances lasted for 4 weeks in open surgery and 1 week in laparoscopic surgery, demonstrating that minimally invasive surgery caused lesser sleep disturbance than open surgery.[16] Rosenberg-Adamsen et al. also showed that there is considerable variation in the sleep architecture, with reduction in the duration of REM sleep and slow-wave sleep postoperatively.[24] A study examining late postoperative nocturnal hypoxemia and associated sleep patterns showed that there was decreased postoperative REM sleep initially, with a rebound increase in the duration and number of episodes of REM sleep later on, with slow-wave sleep, in turn, decreasing significantly during the postsurgical period.[25] Knill et al. showed that anesthesia with abdominal surgery led to intense increase in REM sleep during the postoperative period.[26]

Closs reported that pain was the most common cause of sleep disturbance postsurgery and that analgesics helped improve sleep more than any other intervention.[27] Dolan et al., who analyzed sleep disturbance and deprivation in surgical patients, reported that pain was the main factor responsible for sleep disturbance, both preoperatively and postoperatively, and environmental factors, i.e., disturbance from nursing staff and noise in the ward became more apparent in the postoperative period.[6] From this, it follows that pain management becomes especially important and will have a significant impact in improving sleep quality. Our study showed postoperative sleep disturbances across all room types, without significant variation with room types. However, Dolan et al. also observed that sleep disturbance decreased with less number of patients in one ward, indicating that lesser number of patients in each ward would vastly improve sleep quality.[6] The reasons for this could possibly be reduction of noise and lesser number of nursing interventions taking place in the ward.

Strengths and limitations of the study

The strength of the present study is that it used a standard tool to evaluate sleep quality, which provided us with comparable data. However, it also has certain limitations. The sample size was small and study participants were chosen by convenience sampling, which made it difficult to generalize the study results to the overall population. There was also potential for recall bias as the questionnaire was administered retrospectively, a month after the surgery, when the patient was called for re-interview. We did not assess the type and duration of sleep medications used in the past, which could possibly have had an effect on the current quality of sleep, as various sedatives and hypnotics affect sleep quality and architecture in different ways. Besides the small sample size, the subgroups in each type were also much smaller and heterogeneous, as we included patients of different age groups and those undergoing various kinds of surgeries, which resulted in nonsignificant results with regard to several associations, which otherwise have had significant results in other similar studies.

  Conclusion Top

The present study shows that there is significant reduction in the quality of sleep in the postoperative period as compared to the preoperative period. This can get further exacerbated with the use of GA for surgery, increasing age of the patient, and the use of sleep medications, which affect sleep architecture. In addition, the type of surgery and the surgical stress response might also contribute to poor postoperative sleep. As this can have several adverse effects on the postoperative recovery of the patient, it is necessary to identify the factors responsible, address these issues as early as possible, and apply interventions to reduce postoperative stress and sleep disturbance. Further studies are necessary, which employ objective methods of sleep quantification such as electroencephalography, electrooculogram, and electromyogram, which will allow objective evaluation of the level of deterioration of sleep quality in the postoperative period. The nursing staff and also the patients' caregivers and bystanders should be educated about the importance of sleep, the implications of poor sleep to the patient, and the ways to recognize the factors responsible for sleep disturbance and should be trained to reduce disturbance, which can consequently improve sleep quality of the patients.

Using regional anesthesia wherever possible, reducing the surgery time whenever possible and keeping it to a minimum, restricting monitoring to whenever necessary only, alleviation of postoperative pain by administering sufficient analgesia, and using newer z-drugs which do not alter sleep architecture are some of the management strategies which can be tried to improve postoperative sleep disturbance.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Carskadon MA, Dement WC. Normal human sleep: An overview. Princ Pract Sleep Med 2005;4:13-23.  Back to cited text no. 1
Sleep Deprivation. McGraw-Hill Concise Dictionary of Modern Medicine; 2002. Available from: https://www.medical-dictionary.thefreedictionary.com/sleep+deprivation. [Last accessed on 2018 May 16].  Back to cited text no. 2
Sleep Deprivation. Farlex Partner Medical Dictionary; 2012. Available from: https://www.medical-dictionary.thefreedictionary.com/sleep+deprivation. [Last accessed on 2018 May 16].  Back to cited text no. 3
Desborough JP. The stress response to trauma and surgery. Br J Anaesth 2000;85:109-17.  Back to cited text no. 4
Hilakivi I. Biogenic amines in the regulation of wakefulness and sleep. Med Biol 1987;65:97-104.  Back to cited text no. 5
Dolan R, Huh J, Tiwari N, Sproat T, Camilleri-Brennan J. A prospective analysis of sleep deprivation and disturbance in surgical patients. Ann Med Surg (Lond) 2016;6:1-5.  Back to cited text no. 6
Lane T, East LA. Sleep disruption experienced by surgical patients in an acute hospital. Br J Nurs 2008;17:766-71.  Back to cited text no. 7
Edwards H, Rose EA, Schorow M, King TC. Postoperative deterioration in psychomotor function. JAMA 1981;245:1342-3.  Back to cited text no. 8
Gill NP, Wright B, Reilly CS. Relationship between hypoxaemic and cardiac ischaemic events in the perioperative period. Br J Anaesth 1992;68:471-3.  Back to cited text no. 9
Yoo SS, Gujar N, Hu P, Jolesz FA, Walker MP. The human emotional brain without sleep – A prefrontal amygdala disconnect. Curr Biol 2007;17:R877-8.  Back to cited text no. 10
Thomas M, Sing H, Belenky G, Holcomb H, Mayberg H, Dannals R, et al. Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. J Sleep Res 2000;9:335-52.  Back to cited text no. 11
Durmer JS, Dinges DF. Neurocognitive consequences of sleep deprivation. In: Seminars in Neurology. Vol. 25. New York, USA: Thieme Medical Publishers Inc.; 2005. p. 117-29.  Back to cited text no. 12
Besedovsky L, Lange T, Born J. Sleep and immune function. Pflugers Arch 2012;463:121-37.  Back to cited text no. 13
Buysse DJ, Reynolds CF 3rd, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh sleep quality index: A new instrument for psychiatric practice and research. Psychiatry Res 1989;28:193-213.  Back to cited text no. 14
Beliaev DG, Shestokov IP, Zadorozhnaia OA, Fridman MK. Insomnia and its treatment during the postoperative period. Anesteziol Reanimatol 1994;1:37-40.  Back to cited text no. 15
Eisen J, MacFarlane J, Shapiro CM. ABC of sleep disorders. Psychotropic drugs and sleep. BMJ 1993;306:1331-4.  Back to cited text no. 16
Perry SW, Wu A. Rationale for the use of hypnotic agents in a general hospital. Ann Intern Med 1984;100:441-6.  Back to cited text no. 17
Gögenur I, Rosenberg-Adamsen S, Kiil C, Kjaersgaard M, Kehlet H, Rosenberg J, et al. Laparoscopic cholecystectomy causes less sleep disturbance than open abdominal surgery. Surg Endosc 2001;15:1452-5.  Back to cited text no. 18
Gögenur I, Wildschiøtz G, Rosenberg J. Circadian distribution of sleep phases after major abdominal surgery. Br J Anaesth 2008;100:45-9.  Back to cited text no. 19
Leardi S, Tavone E, Cianca G, Barnabei R, Necozione S, Citone G, et al. The role of melatonin in the immediate postoperative period in elderly patients. Minerva Chir 2000;55:745-50.  Back to cited text no. 20
Kain ZN, Caldwell-Andrews AA. Sleeping characteristics of adults undergoing outpatient elective surgery: A cohort study. J Clin Anesth 2003;15:505-9.  Back to cited text no. 21
Tranmer JE, Minard J, Fox LA, Rebelo L. The sleep experience of medical and surgical patients. Clin Nurs Res 2003;12:159-73.  Back to cited text no. 22
Yasuma F, Okada T. Sleep disturbances complicated by surgical stress; a questionnaire survey of 50 patients. Masui 1989;38:66-70.  Back to cited text no. 23
Rosenberg-Adamsen S, Kehlet H, Dodds C, Rosenberg J. Postoperative sleep disturbances: Mechanisms and clinical implications. Br J Anaesth 1996;76:552-9.  Back to cited text no. 24
Rosenberg J, Wildschiødtz G, Pedersen MH, von Jessen F, Kehlet H. Late postoperative nocturnal episodic hypoxaemia and associated sleep pattern. Br J Anaesth 1994;72:145-50.  Back to cited text no. 25
Knill RL, Moote CA, Skinner MI, Rose EA. Anesthesia with abdominal surgery leads to intense REM sleep during the first postoperative week. Anesthesiology 1990;73:52-61.  Back to cited text no. 26
Closs SJ. Patients' night-time pain, analgesic provision and sleep after surgery. Int J Nurs Stud 1992;29:381-92.  Back to cited text no. 27




Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Materials and Me...
Article Tables

 Article Access Statistics
    PDF Downloaded290    
    Comments [Add]    

Recommend this journal