QUALITY OF SLEEP IN POSTOPERATIVE SURGICAL ONCOLOGIC PATIENTS

El objetivo del estudio fue evaluar la calidad del sueño en pacientes quirúrgicos oncológicos, utilizando el cuestionario Índice de Calidad del Sueño de Pittsburgh (PSQI), para mensurar la calidad subjetiva del sueño y la ocurrencia de disturbios. Consistió en una investigación con delineamiento observacional transversal, envolviendo 46 pacientes con diagnóstico de cáncer, sometidos a procedimientos quirúrgicos de las especialidades Cabeza Cuello y Urología. Seis componentes del PSQI fueron estadísticamente significativos y 73,9% de los entrevistados presentaron comprometimiento de la calidad del sueño. Entre las causas de los disturbios del sueño se destaca: demorar para dormir, despertar en el medio de la noche, levantarse para ir al baño y dormitar durante el día. Se espera que este estudio sensibilice al equipo de enfermería sobre la necesidad de investigar la calidad y las causas de los disturbios del sueño en sobrevivientes de cáncer, para que haya una intervención efectiva.


INTRODUCTION
According to the National Cancer Institute in Brazil, the incidence of cancer increases at the same rate as the population ages due to increased expectation of life.According to the institute, surgery is still one of the main treatments for 60% of patients.
Many tumors can be treated only with surgery while others need to be treated with a combination of surgery and radiotherapy and/or chemotherapy (1) .
The sleep disorders experienced by cancer patients can occur in different periods of the course of the disease: at the point of diagnosis, during and after treatment and in its final phase.The incidence of this disorder for these patients is expressive because it is about 30 to 50% when compared to 15% in the population in general.In addition, 23% to 44% of cancer patients present this symptom after two or five years of treatment (2) .The first REM period occurs 70 to 90 minutes after the beginning of sleep, normally with a short duration of five to 15 minutes.In general, the four or five REM episodes have their duration lengthen during the night (3) .

Sleep is well organized and structured in cycles
The whole sleep regulatory mechanism described above is altered in cancer patients due to several reasons and can cause insomnia, difficulty in falling asleep, drowsiness, nightmares, sleep interruptions in the middle of the night, staying awake for long periods, difficulties resuming sleep, waking up too early in the morning and napping during the day (4) .
The authors of this study became concerned with the theme after analyzing the Oncology Nursing Society (ONS) (5)  Accordingly, when the Brazilian literature in nursing was searched, we noted that the sleep theme is an incipient field with few studies published in the country.Three studies are highlighted because they contribute to understanding the issue concerning people with diabetes (6) , women undergoing elective gynecological surgeries (7) , and women with gynecological and breast cancers (8) .
The Patients from the head and neck and urology specialties were selected due to the large number of both large and medium oncologic surgeries performed every year at the institution.These are also fields in which the main author teaches and delivers services for the community, which facilitated the agreement of the surgeons responsible for approving the study.

METHOD
This study is an exploratory study with a transversal-observational design in which participants are evaluated a single time (9) .The study population was composed of all oncologic surgery patients from the head and neck and oncology specialties at a hospital and who met the following inclusion criteria: The Pittsburg Sleep Quality Index (PSQI) was used for data collection and another instrument was developed to identify patients' social and clinical characteristics.The PSQI was validated for the Brazilian culture (10) .This instrument was used to alterations in disposition and enthusiasm to perform daily tasks (6) .
When the instrument was applied, patients were oriented to answer questions considering their sleep habits only during the last month, in the majority of days and nights.
The global score is determined by the sum of the seven components and each one received a score between zero and three points.The maximum instrument score is 21.Scores higher than five indicate a poor quality of sleep pattern.
A database was created using Excel ® and then transferred to the Statistical Package for the Social Sciences (SPSS) for analysis.
The PSQI's internal consistency was checked by Cronbach's alpha coefficient.This is obtained after a single application of the measurement instrument, which produces values between 0 and one or between 0 and 100%.When it is higher than 70% we say the measures are reliable.All correlations (p) between each item score and the total score of the remaining items were calculated (11)   .For this study, p<0.05 was considered statistically significant.The PSQI was submitted to Cronbach's alpha and the result was 0.79, higher than 0.70, which indicates the items high internal consistency and homogeneity (11)   .In relation to the PSQI global score, 34 (73.9%)scored higher than five, which indicates their subjective quality of sleep was compromised.not once, 2-less than once a week, 3-once or twice a week and 4-three times a week or more Some items are noteworthy like the 19 patients (41.3%) who take more than thirty minutes to fall to sleep, 32 (69.5%) who wake up in the middle of the night or too early in the morning and 33 (71.7%) who wake up to go the bathroom.The ANOVA test revealed three statistically significant scores: economic income, schooling and site of cancer.

DISCUSSION
Forty-one (89.1%) patients were older than 50 years of age, which is in accordance with the literature because age is an important risk factor for all types of cancer since the incidence and mortality of the disease increase exponentially after 50 years of age (1) .Statistical significance was not found in relation to the quality of sleep with age and gender.
Income up to two minimum wage salaries (71.7%) and schooling up to elementary school (80.5%) indicate patients who live in poor living conditions due to their lack of professional qualifications and low educational level.They also have limited access to public services such as the health and educational systems, which limit preventive practices and early detection (12) .These social characteristics can also hinder the knowledge of these patients regarding complementary treatments that can minimize sleep disorders.Financial difficulties can also generate worries that interfere with sleep patterns.A systematic review (13) that evaluated the use of alternative and complementary treatments among patients with cancer shows that patients who use these therapies are those with a high level of education and high family income.
These findings are compatible with the findings of this study because income and schooling were statistically significant in relation to the PSQI global score, confirming the importance of these aspects for the sleep quality of these patients.
A study (8) evaluating the sleep quality of The site of cancer was also a statistically significant variable (p=0.023).It is known that the site and stage of the disease determine the kind of treatment chosen and also affect the recovery and quality of life of those who survive it (14)   .In patients submitted to prostatectomy, the average quality of sleep, according to the PSQI global score, was 8.25.
In this group, one of the causes disturbing their sleep was the need to wake in the middle of the night to go to the bathroom, usually leaving them unable to fall back to sleep; another factor was the preoccupation of not being able to keep an active sexual life with their partners.
Although the frequency of patients submitted to chemotherapy and radiotherapy was small, one cannot forget to mention the importance of these therapies for sleep quality.Cancer patients who were submitted to specific treatments in the last six months were more subject to problems of excessive somnolence (8) .
Twenty-four (52.2%) patients in this sample slept less than six hours on average.This finding differs from another study (15) with 123 cancer patients in which 95% of the individuals had an average of 6.58 hours of sleep.However, the literature (16) also reveals that when sleep disorders exist before the disease, the symptoms worsen in 58% of the patients after the diagnosis.
Another study that focused on the poor sleep quality of cancer patients (8) highlighted the following problems: early waking (92%) and the need to go to the bathroom (92%), followed by episodes of pain (69.3%) and sensation of heat during the night (46.2%).These findings are similar to those of this study in which 27 (58.7%)patients reported poor or very poor sleep patterns.
Regarding the habit of napping (answers to the PSQI question ten) Table 3 shows that 34 (73.9%)participants reported they intentionally take a nap during the day.We also observed that 21 (45.6%)consider napping to be pleasurable and 13 (28.3%)consider it a necessity.The act of napping in the morning or afternoon was also found in 39% of the respondents of another study and 60 % of them nap at least three times a week (16) .Thus, naps during the (i.e.fatigue); and there is also the possibility that one or more symptoms are triggered by another symptom (sleep disorder that can lead to fatigue) (14) .
Sleep patterns have to be determined in order to evaluate whether sleep quality is adequate.For that, professionals in the health field should investigate patients' routines so as to determine the time when they go to bed, how long they take to fall to sleep, sleep duration, number of times they wake during the night, how long they take to resume sleeping and napping during the day, or limit it to 20 minutes, and avoid napping after 3PM (17) .

CONCLUSIONS
of NREM-REM, which occur about four or five times during the night.A young and healthy adult enters sleep through NREM stages or phases.Stage one is a brief transitional period between being awake and asleep, which lasts five minutes and is considered light sleep.The stage two lasts 10 to 20 minutes during the initial cycle and is considered true physiological sleep.Stages 3 and 4, also called delta or slow waves, are the deepest ones and can last 20 to 40 minutes in the first cycle.The initial sequence is followed by a return to stages 4, 3 and 2, followed by a REM episode.
evaluate the subjective quality of sleep and occurrence of its disorders.It contains ten questions, items one to four are open questions and five to ten are semiopen questions.If interviewees wished and deemed necessary they could add comments to any of the questions in space provided for that.The PSQI has seven components: the first is the subjective quality of sleep, that is, the individual perception of sleep quality; the second is sleep latency; the third is sleep duration, obtained through the relation between the number of hours slept and the number of hours spent in bed, not necessarily sleeping; the fourth is related to habitual sleep efficiency; the fifth is sleep disorders, that is, situations that compromise sleep hours; the sixth is the use of medications, that is, whether the patient uses medications to sleep; the seventh is related to diurnal sleepiness and disorders during the day and refers to women with cancer, however, shows different results because the level of education was similar among individuals with good and poor quality of usual sleep (average of 4.5 and 5 years of schooling, respectively) as well as family income: five minimum wage salaries predominated (in 91.7% of the participants with good sleep patterns and in 84.6% of those with poor sleep patterns).
day might be associated with interrupted sleep during the night, which in turn contributes to poor sleep quality.Hence, when the PSQI components are jointly evaluated in relation to the global score we have a better understanding of the relation between them.A person who sleeps less than five hours per night and takes more than thirty minutes to fall asleep is considered to have a poor quality of sleep and consequently might become sleepy during the day and feel the need to nap.Disorders in sleep patterns indicate sleep is being harmed by environmental and/or personal factors.It is important to note that studying the multiple symptoms of cancer is a complex task because of the differences found in the origin of the disease and specific symptoms.Some symptoms are related to the disease and others are related to the treatment (i.e.nauseas and vomiting can be the result of intestinal obstruction or chemotherapy); or yet symptoms can be related to the disease and treatment This study aimed to evaluate the sleep quality of 46 surgical cancer patients in the head and neck and urology specialties through the Pittsburgh Sleep Quality Index and a specific instrument to identify the social and clinical characteristics of patients.Results show that all patients value sleep and the main disorders are: taking too long to fall sleep and discontinued nocturnal sleep.Income, schooling and site of the disease were statistically significant factors for quality of sleep.The participants expressed the need to nap during the day, which can be a necessity for some, but might lead, at the same time, to disorders in nocturnal sleep.Comparing the results of this study with other studies we find that there are differences in sleep quality among groups of cancer patients, which lead to the conclusion that focusing on the site of disease and specific treatments leads to more accurate results.This study presents some limitations due to the heterogeneous sample because the consequences of surgeries in the head and neck are different from urological ones.The sample is composed of 46 patients, which can be considered a small number if compared to the number of cancer patients attended per year at the institution.Another limitation is related to the transversal-observational design.A longitudinal study can complement the evaluation of sleep quality in different stages of the disease.Such limitations can be overcome in future studies.

Table 1
presents the answers to the PSQI's first four open questions and tables 2 and 3 refer to the semi-open questions from five to ten with items' frequency and percentage.We observed that the most frequent time to go to bed was between 9 and 11 P.M. for 80.4% of the participants, 37% took up to 15 minutes to sleep, 54.3% woke up after six to seven hours of sleep and 26.1% slept six to seven hours per night on average.

Table 1 -
Frequencies and percentage of participants' answers to the PSQI semi-open questions.Uberaba,

Table 2 -
Frequency and percentage of participants' answers in the PSQI semi-open questions.Uberaba (MG),

Table 4 -
Average, standard deviation and statistical significance of the PSQI components in relation to its global score.Uberaba (MG), 2008.

Table 4 .
Table 5 presents the results of the parametric test ANOVA with values statistically significant in relation to the instrument items, which refer to patients' social and clinical characteristics.
Based on the above, implementing interventions so that cancer patients acquire healthy sleep habits include: keep a regular time to sleep and wake up (even during weekends); go to bed only when feeling sleepy; get up when not able to resume sleeping after 15-20 minutes and go to another room, then perform a non-stimulating activity until feeling sleepy; sleep only the necessary amount; exercise regularly, which should be done four to six hours before going to bed; eat a light meal before going to bed; avoid heavy foods; reduce the level of noise and light; avoid stimulants such as nicotine, food and drinks with caffeine four to six hours before going to bed (i.e.chocolate, coffee and soft drinks); avoid drinking alcohol because it causes nocturnal waking; avoid