Journal of Advanced Nursing, 1976, i , 453-468
Quantity and quality of patients' sieep and sieep'disturbing factors in a respiratory intensive care unit B.Ann Hilton R.N. B.S.N. M.S.N. Assistatit Professor, University oj British Columbia School of Nursing, Vancouver, Canada Accepted for publication lj June
igj6
HILTON B . A N N (H)-J6) Journal of Advanced Nursun^ I, 453-468
Quantity and quality of patients' sleep and sleep-disturbing factors in a respiratory intensive care unit This descriptive sttidy tisiiig continuous polygraplnc recording, observation and interview attempted to identify the quantity and qtiality of sleep and the factors which disturbed the sleep of selected patients in a respiratory intensive care unit. Documentation of behaviour which might be related to sleep deprivation and identification of factors which the patients perceived as interfering witli rest and sleep were also recorded. It was concluded that patients had ditficulty meeting their 'normal' needs for sleep dnc to frequent interrtiptions and possible sleep-disturbing factors. Behavioural changes related to sleep deprivation were observed.
INTRODUCTION Inability to obtain sutFicicnt sleep, a basic and vital tieed, is a common complaint of hospitalized patients. Those in intensive care units (ICU) are particularly subject to sleep disturbance. Watts (1969) suggested that the busy intensive care environment is the opposite of peace and quiet required for the recovery from serious illness. The nurse is the key person in the provision of individualized constant surveillance and coorditiated care on a 24-hour basis in intensive care. Walker (1972) stated it should be possible to help patients meet their sleep needs more adequately, even though they are affected by physiological, psychological and environmental stresses, and still to provide adequate intensive care nursing. Due to the critical nature ofthe patient's illness in the respiratory ICU and the essential need for continuous monitoring and care, the normal sleep patterns and cycles are highly susceptible to interruptions and changes. The problem posed for 453
B. A. Hilton
454
study was: documentation of the sleep patterns of patients in a respiratory ICU and identification of the factors which disturbed their sleep.
Background of the problem Sleep is characterized by rhythms and cycles indicated by biological, behavioural and electroencephalographic (EEG) alterations. The average normal night's sleep consists of 4-5 sleep cycles, with each ofthese being 90-120 minutes long. Four sleep stages and dream sleep generally occur within a cycle ina predictable pattern (US Department of Health, Education, and Welfare 1973). Dream sleep may he referred to as stage REM because of the rapid eye movements characteristic of this stage. Figure i illustrates the orderly progression of stages i, 2, 3, 4, 3, 2 and REM sleep. After 50-90 minutes, sleep lightens and the first dream period usually occurs. After dreaming, which may last approximately 20 minutes, there is a Awake REM 1 a> m* 2 [/)
«
4
1 FIGURE I
2
3
4 5 Hours of sleep
i
f
6
7
Normal itocturiial sleep patterns in young adults (source: Kales 1968)
gradual deepening of sleep usually back to stage 4. Most deep sleep, often called stage 4, occurs in the first 3 or 4 hours of sleep and then toward wakening does not occur at all The reverse is true of dream sleep. Predictable percentages of different stages in a night's sleep have been determined for various age groups. For the young adult, stage 1 occupies 5% of the nocturnal sleep pattern; stage 2 occupies 50-55%; each of stages 3 and 4 occupies 10%, and stage REM occupies 20-25%. In the middle-aged and elderly adults, stage 4 is decreased to 0-4%; and stage REM is decreased to 18-25% (Kales & Kales 1970). The sleep needs of individuals vary from as little as 3-4 hours a night to an average of 7-7^ hours. This normal sleep pattern can be influenced by many factors such as age, sex, noise, drugs, subjective feelings regarding sleep, anoxia and shift work. Sleep deprivation produces lower levels of arousal, increases in stages 3 and 4, decreases in stage i, and decreases in the time taken to go to sleep. Following either stage 4 deprivation or total sleep deprivation, there was a significant increase in stage 4 sleep even at the expense of other sleep stages (Williams et al. 1964). In
Patients' sleep in a respiratory intensive care unit severely dreani-dcprivcd subjects, the REM stage was found to succeed wakefulness rather than deep sleep {Kooi 1971). General sleep deprivation effects include lassitude, decreased mobility, sensory changes, visual and auditory illusions, hallucinations, disorientation and others. The patient in intensive care is affected by his pathophysiological status with its accompanying discomforts, necessary mechanical apparatus, constant observation periods and therapies, lack of privacy and meaningful stimuli, as well as by his personal reactions to illness, hospitalization, and life and family problems. All of these contribute to stress in the patient and stress may be a sleep-inhibiting factor. Monitoring machines and vital supportive equipment may be disturbing or reassuring and thus inhibit or promote sleep. Minor malfunctions may seem major threats to the sick person. Davis (T972) thought uniformity and lack of meaningful and familiar stimulation rather than sensory deprivation or overstimulation were significant for these patients. The care of the patient in an ICU involves a team of people each of whom requires time with the patient. This multiplicity of involvement may be uncoordinated. McFadden (1968), Garner (1969), Dowd (1968), Kinash (1972) and Walker's (1972) studies, using subjective criteria for the presence of sleep, reported frequent interruptions and disturbance thereby making it difficult for the patient to meet his sleep needs. With the emergence of IGUs and open-heart surgery, 30-70% ofthe openheart surgery patients suffered delirium 3-5 days postoperatively (Egerton & Kay 1964). Sleep deprivation is held to be a factor. Other prime factors were patient history of psychosis, sensory-deprivation, older age, and a multiplicity of causes. The onset of delirium of 3-5 days corresponds with the development of behavioural manifestations of sleep deprivation (Kornfeld 1971). Kinash and McFadden reported behavioural changes which might have been related to their subjects' apparent sleep deprivation and that there was a possible relationship between the deprivation and behavioural changes noted.
Statement of purposes The primary purpose of the study was to document the quantity and quality of sleep and to identify the factors which disturbed the sleep of selected patients in a respiratory IGU. The purpose included documentation of behaviour which might be related to sleep deprivation and identification of factors which the patients in the respiratory IGU perceived as interfering with rest and sleep. The ultimate purpose of this investigation was the provision of care that is more conducive to patients' rest and sleep. METHOD A descriptive approach was selected. Data was collected by continuous observation, sleep stage monitoring, sleep-disturbing factor recording, and interviewing. Patients from the respiratory IGU of a large university teaching hospital were selected.
455
456
B. A. Hilton
To obtain objective and accurate measurement of stages and cycles of sleep, polygraphie recording on an electroencephalographic machine was used to document brain wave potentials (EEG), eye movements (EOG), and skeletal muscle tension (EMG) for forty-eight continuous hours. Factors which might be interpreted as sleep-disturbing to the patient or which might have prevented patients from resting or sleeping were recorded. Observations of unusual behaviour which might have been related to sleep deprivation were also recorded. Approximately one week following transfer from the ICU, each patient was interviewed to ascertain his normal sleep patterns; to identify factors which he or she believed prevented the obtaining of rest and sleep; and to record the recall and perceptions of unexplained experiences. Other sources of patient data were used to complete the patient profiles and to determine whether drugs for analgesia or sedation had been administered during the study period.
Techniques used for polygraphie sleep recording Standardized nomenclature and methods for recording and scoring sleep recordings developed by the Association for the Psychophysiological Study of Sleep were used as the source of technique. Identification ofthe sleep stages is possible by monitoring EEG, HOG and EMG. The polygraphie tracings were made at a paper speed of fifteen millimetres per second on an eight channel Mingograff electroencephalographic machine. Two channels of EEG, two channels of EOG and one channel of EMG were used. Needle electrodes were used for scalp placement, ear clips and surface electrodes for eye and chin areas. Figure 2 illustrates the placement of these electrodes.
FIGURE 2 Placement of EEG, EMG, ant! EOG electrodes for recording sleep stages (source: Rcchtschaffen & Kales ig68}
Patients' sleep in a respiratory intensive care unit
457
Assumptions 1 Sleep is beneficial. 2 Sleep which approximates the normal sleep pattern is more beneficial. 3 Normal sleep patterns are individualized. 4 It is possible to discern factors that waken the patient or prevent him from resting or sleeping. 5 It is possible to identify unusual behaviour associated with sleep deprivation. Definitions Sleep: (defined polygraphically and sleep stages scored according to Rechtschaffen d< Kales 1968). These are illustrated in Figure 3 which is a sample from the investigator's study. Stage I—2-7 cycles per second waves of low voltage occurring amongst mixed frequency EEG. This was accompanied by slow eye movements and muscle tone below the level of wakefulness. Sharp vertex waves with amplitudes as high as 200 microvolts appear in the latter part of stage i. Staj^e 2—sleep spindles which are 6 or 7 distinct waves in a half-second period and/or K complexes which are well-defined negative sharp waves immediately followed by a positive component with a duration exceeding one-half second. If more than 3 minutes lapses where no spindles or K complexes occur, the stage is defined as stage i. Stage 3—at least 20-49% ofthe epoch consists of waves of 2 cycles per second or slower with amplitudes greater than 75 microvolts. Stage 4—more than 50% ofthe epoch consists of waves of 2 cycles per second or slower with amplitudes greater than 75 microvolts. Stage REM^relatively low^ voltage, mixed frequency waves, 'saw-tooth' waves, and waves of 8-13 cycles per second. There is an absence of sleep spindles, K complexes and vertex sharp waves. Muscle tone reaches its lowest level although transient increases in this tonic activity may occur. Rapid eye movements might be absent in this stage as long as the other requirements ofthe stage were met. Intervals of less than 3 minutes between sleep spindles were termed stage 2 regardless of muscle tone level if there were no rapid eye movements or movement arousals. Stage W{u'akejiihies-:)—8-13 cycles per second and/or low voltage mixed frequency waves, rapid eye movements, possibly eye blinks, and high muscle tone. Normal sleep cycle: A normal sleep cycle is approximately 90-120 minutes long and is characterized by the progression of stages from stage i-2-3-4-3-2-stage REM. An uninterrupted period of 90-120 minutes is required to complete a sleep cycle. Behaviour related to sleep deprivation: Behaviour observed by the investigator and/or recalled by the patient as an inexplicable experience, such as: mumbling; slurred and rambling speech; disordered thinking; demand for more attention than usual; exaggerated anger when attention is not given; frequent
B. A. Hilton
EMG
20/iV
EEG EOG
|
1 second
1 second
FIGURE 3 Stages of sleep using electroencephalogram (EEG), muscle tone (UMG), and eye movement (EOG) recordings
A Stage W (wakefulness)—the EEG contains alpha activity and/or low voltage, mixed frequency activity. Rapid eye movements and high muscle activity are present B Stage I—a relatively low voltage mixed frequency EEG without rapid eye movements C Stage 2—12-14 cycles per second sleep spindles (underlined) and K complexes (arrow) on a background of relatively low voltage, mixed frequency EEG activity D Stage 3—moderate amounts of higli amplitude, slow wave activity E Stage 4—-large amounts of high amplitude, slow wave activity F Stage REM—a relatively low voltage, mixed frequency EEG in conjunction with episodic REMs and low amplitude EMG
Patients' sleep in a respiratory intensive care tuiit complaints and arguments; sensory disturbance; diplopia; visual illusions or hallucinatiotis; auditory hallucinations; nightmares; disorientation; delusions; paranoia; motor impairment; hyperactivity; and restlessness. Definite sleep-disturbing factor: any factor which wakens the patient trom any stage of sleep or changes the level toward wakefulness. Possible sleep-disturbing factor: any factor which may have kept the patient awake or prevented him from obtaining uninterrupted sleep patterns.
Sample To be eligible for inclusion in the sample the patients were eighteen years of age or over, conscious and rational, able to see, hear, and comprehend the English language, agreed to participate in the study, were not sufFeritig from a drug overdose, head injury, or any neurological problem which would affect the sleep recordings, and did not have a cardiac pacemaker. Permission from their attending physician was also obtained. Ten subjects constituted the study sample, varying in age from 34-81 years. All patients had respiratory insufficiency although their primary medical diagnoses varied. Data were incomplete for four patients in areas of continuous 48-hour recording, observation, or interview. The fnidings must be interpreted in the light ofthe fact that only a small number of patients was studied. There is a possibility that an observer's presence at the patient's bedside may have altered the fmdings to promote more or less sleep. Six observers were involved in collecting the data.
Method of scoring sleep stages Frequencies, amplitudes and wave patterns were considered for the EEG, EOG and EMG channels in identifying and scoring sleep stages, the characteristics of which were given in the defmitiotis. One page of record was twelve inches long and was called an epoch. At a paper speed of fifteen millimetres per second, an epoch occupied twenty seconds. All recordings were analysed by hand by the investigator. Each epoch was assigtied a single stage score based on the stage which predominated in that epoch.
Reliability cbeck A pretest was done on one patient. The investigator also recorded her own sleep by the same methods in the laboratory for one night, to determine whether the patient was being exposed to any additional discomforts by participating in the study. It was concluded that the patient was not being exposed to additional discomforts. The investigator's night record and a 24-hour period of a subject s record were checked for reliability of scoring sleep stages by a neurosurgeon involved in sleep studies,
459
46o
B. A. Hiltoti
THE FINDINGS Quantity of sleep A comparison of tlic subjects' nonnal sleep pattems and the norms cited in the literature indicated that patients had less total sleep time than normally and that the percentages of time in the sleep stages were not that of the normal cycle. Total sleep time ranged from six minutes to i3'3 hours during a 24-hour period (see Table i). Only 50-60% of the sleep occurred during the night period as contrasted TABLE I
Quantity of steep during 24-liour periods atid night periods Xorinal hours sleepl24 hours as reported hy subjects
Subject
'iota! slee[ hours
First night
Second 24 hotirs 3-3
I-irsI 24
Second night
1
,s
5-9
2-9
4 5
9
2-3
6-.S-S-5
3-0 o-t
0
2-6
6
*
7-0
2-0
7 9
S-5t
5-9
5-0
S-4 6-9
6-8 8
17
13
13-3
4-6
8-0
5-3
2-6
5-8
37 3-3 47 3-5
TOO-O
49-1
roo-Q
60-4
10
Average Percentage
2-2
4-0
41 9-2
2-3 4T
* Patient deceased I Includes a 2-hoiir nap
to almost 100% of that they normally experienced at home. Table 2 compares the predictable percentage stage time to the subjects. Stage i predominated to the deprivation of all other stages, especially stage 4 (deep sleep) and REM (dream sleep). Analgesics and sedatives tended to promote stages i and 2 sleep and at the same time there was decrease in the other stages. TABLE 2
Stage I
Comparison of'iwrntal' stage percentages to stihject stage percentages Nortital stage % * Middle-aged and elderly \'ou>ig adult differences
5
" > / sleep stages
First 24 hours
Second 24 hours
49 4t 7
43
32
2
.SO-55
3
10
4
iO
0-4
0-1
4-5
20-25
18-2.S
3-6
6-0
REM
* Source of the normals are from Kales & Kales (1970) p. 2234.
14
461
Patients' steep in a respiratory intensive care unit
Stage W
Hour (time) 1 (/5;5)
21 IB/51
912315)
10:00/51
3(1? 15]
4[l8r5)
6('9f5l
REM 1 2 3 4 W
Valium 2 mg 15IO5'SI
16(05/51
22{I2I5]
23113 IS)
245I
37(03/5)
3B
Quantity and quality of patients' sieep and sieep'disturbing factors in a respiratory intensive care unit B.Ann Hilton R.N. B.S.N. M.S.N. Assistatit Professor, University oj British Columbia School of Nursing, Vancouver, Canada Accepted for publication lj June
igj6
HILTON B . A N N (H)-J6) Journal of Advanced Nursun^ I, 453-468
Quantity and quality of patients' sleep and sleep-disturbing factors in a respiratory intensive care unit This descriptive sttidy tisiiig continuous polygraplnc recording, observation and interview attempted to identify the quantity and qtiality of sleep and the factors which disturbed the sleep of selected patients in a respiratory intensive care unit. Documentation of behaviour which might be related to sleep deprivation and identification of factors which the patients perceived as interfering witli rest and sleep were also recorded. It was concluded that patients had ditficulty meeting their 'normal' needs for sleep dnc to frequent interrtiptions and possible sleep-disturbing factors. Behavioural changes related to sleep deprivation were observed.
INTRODUCTION Inability to obtain sutFicicnt sleep, a basic and vital tieed, is a common complaint of hospitalized patients. Those in intensive care units (ICU) are particularly subject to sleep disturbance. Watts (1969) suggested that the busy intensive care environment is the opposite of peace and quiet required for the recovery from serious illness. The nurse is the key person in the provision of individualized constant surveillance and coorditiated care on a 24-hour basis in intensive care. Walker (1972) stated it should be possible to help patients meet their sleep needs more adequately, even though they are affected by physiological, psychological and environmental stresses, and still to provide adequate intensive care nursing. Due to the critical nature ofthe patient's illness in the respiratory ICU and the essential need for continuous monitoring and care, the normal sleep patterns and cycles are highly susceptible to interruptions and changes. The problem posed for 453
B. A. Hilton
454
study was: documentation of the sleep patterns of patients in a respiratory ICU and identification of the factors which disturbed their sleep.
Background of the problem Sleep is characterized by rhythms and cycles indicated by biological, behavioural and electroencephalographic (EEG) alterations. The average normal night's sleep consists of 4-5 sleep cycles, with each ofthese being 90-120 minutes long. Four sleep stages and dream sleep generally occur within a cycle ina predictable pattern (US Department of Health, Education, and Welfare 1973). Dream sleep may he referred to as stage REM because of the rapid eye movements characteristic of this stage. Figure i illustrates the orderly progression of stages i, 2, 3, 4, 3, 2 and REM sleep. After 50-90 minutes, sleep lightens and the first dream period usually occurs. After dreaming, which may last approximately 20 minutes, there is a Awake REM 1 a> m* 2 [/)
«
4
1 FIGURE I
2
3
4 5 Hours of sleep
i
f
6
7
Normal itocturiial sleep patterns in young adults (source: Kales 1968)
gradual deepening of sleep usually back to stage 4. Most deep sleep, often called stage 4, occurs in the first 3 or 4 hours of sleep and then toward wakening does not occur at all The reverse is true of dream sleep. Predictable percentages of different stages in a night's sleep have been determined for various age groups. For the young adult, stage 1 occupies 5% of the nocturnal sleep pattern; stage 2 occupies 50-55%; each of stages 3 and 4 occupies 10%, and stage REM occupies 20-25%. In the middle-aged and elderly adults, stage 4 is decreased to 0-4%; and stage REM is decreased to 18-25% (Kales & Kales 1970). The sleep needs of individuals vary from as little as 3-4 hours a night to an average of 7-7^ hours. This normal sleep pattern can be influenced by many factors such as age, sex, noise, drugs, subjective feelings regarding sleep, anoxia and shift work. Sleep deprivation produces lower levels of arousal, increases in stages 3 and 4, decreases in stage i, and decreases in the time taken to go to sleep. Following either stage 4 deprivation or total sleep deprivation, there was a significant increase in stage 4 sleep even at the expense of other sleep stages (Williams et al. 1964). In
Patients' sleep in a respiratory intensive care unit severely dreani-dcprivcd subjects, the REM stage was found to succeed wakefulness rather than deep sleep {Kooi 1971). General sleep deprivation effects include lassitude, decreased mobility, sensory changes, visual and auditory illusions, hallucinations, disorientation and others. The patient in intensive care is affected by his pathophysiological status with its accompanying discomforts, necessary mechanical apparatus, constant observation periods and therapies, lack of privacy and meaningful stimuli, as well as by his personal reactions to illness, hospitalization, and life and family problems. All of these contribute to stress in the patient and stress may be a sleep-inhibiting factor. Monitoring machines and vital supportive equipment may be disturbing or reassuring and thus inhibit or promote sleep. Minor malfunctions may seem major threats to the sick person. Davis (T972) thought uniformity and lack of meaningful and familiar stimulation rather than sensory deprivation or overstimulation were significant for these patients. The care of the patient in an ICU involves a team of people each of whom requires time with the patient. This multiplicity of involvement may be uncoordinated. McFadden (1968), Garner (1969), Dowd (1968), Kinash (1972) and Walker's (1972) studies, using subjective criteria for the presence of sleep, reported frequent interruptions and disturbance thereby making it difficult for the patient to meet his sleep needs. With the emergence of IGUs and open-heart surgery, 30-70% ofthe openheart surgery patients suffered delirium 3-5 days postoperatively (Egerton & Kay 1964). Sleep deprivation is held to be a factor. Other prime factors were patient history of psychosis, sensory-deprivation, older age, and a multiplicity of causes. The onset of delirium of 3-5 days corresponds with the development of behavioural manifestations of sleep deprivation (Kornfeld 1971). Kinash and McFadden reported behavioural changes which might have been related to their subjects' apparent sleep deprivation and that there was a possible relationship between the deprivation and behavioural changes noted.
Statement of purposes The primary purpose of the study was to document the quantity and quality of sleep and to identify the factors which disturbed the sleep of selected patients in a respiratory IGU. The purpose included documentation of behaviour which might be related to sleep deprivation and identification of factors which the patients in the respiratory IGU perceived as interfering with rest and sleep. The ultimate purpose of this investigation was the provision of care that is more conducive to patients' rest and sleep. METHOD A descriptive approach was selected. Data was collected by continuous observation, sleep stage monitoring, sleep-disturbing factor recording, and interviewing. Patients from the respiratory IGU of a large university teaching hospital were selected.
455
456
B. A. Hilton
To obtain objective and accurate measurement of stages and cycles of sleep, polygraphie recording on an electroencephalographic machine was used to document brain wave potentials (EEG), eye movements (EOG), and skeletal muscle tension (EMG) for forty-eight continuous hours. Factors which might be interpreted as sleep-disturbing to the patient or which might have prevented patients from resting or sleeping were recorded. Observations of unusual behaviour which might have been related to sleep deprivation were also recorded. Approximately one week following transfer from the ICU, each patient was interviewed to ascertain his normal sleep patterns; to identify factors which he or she believed prevented the obtaining of rest and sleep; and to record the recall and perceptions of unexplained experiences. Other sources of patient data were used to complete the patient profiles and to determine whether drugs for analgesia or sedation had been administered during the study period.
Techniques used for polygraphie sleep recording Standardized nomenclature and methods for recording and scoring sleep recordings developed by the Association for the Psychophysiological Study of Sleep were used as the source of technique. Identification ofthe sleep stages is possible by monitoring EEG, HOG and EMG. The polygraphie tracings were made at a paper speed of fifteen millimetres per second on an eight channel Mingograff electroencephalographic machine. Two channels of EEG, two channels of EOG and one channel of EMG were used. Needle electrodes were used for scalp placement, ear clips and surface electrodes for eye and chin areas. Figure 2 illustrates the placement of these electrodes.
FIGURE 2 Placement of EEG, EMG, ant! EOG electrodes for recording sleep stages (source: Rcchtschaffen & Kales ig68}
Patients' sleep in a respiratory intensive care unit
457
Assumptions 1 Sleep is beneficial. 2 Sleep which approximates the normal sleep pattern is more beneficial. 3 Normal sleep patterns are individualized. 4 It is possible to discern factors that waken the patient or prevent him from resting or sleeping. 5 It is possible to identify unusual behaviour associated with sleep deprivation. Definitions Sleep: (defined polygraphically and sleep stages scored according to Rechtschaffen d< Kales 1968). These are illustrated in Figure 3 which is a sample from the investigator's study. Stage I—2-7 cycles per second waves of low voltage occurring amongst mixed frequency EEG. This was accompanied by slow eye movements and muscle tone below the level of wakefulness. Sharp vertex waves with amplitudes as high as 200 microvolts appear in the latter part of stage i. Staj^e 2—sleep spindles which are 6 or 7 distinct waves in a half-second period and/or K complexes which are well-defined negative sharp waves immediately followed by a positive component with a duration exceeding one-half second. If more than 3 minutes lapses where no spindles or K complexes occur, the stage is defined as stage i. Stage 3—at least 20-49% ofthe epoch consists of waves of 2 cycles per second or slower with amplitudes greater than 75 microvolts. Stage 4—more than 50% ofthe epoch consists of waves of 2 cycles per second or slower with amplitudes greater than 75 microvolts. Stage REM^relatively low^ voltage, mixed frequency waves, 'saw-tooth' waves, and waves of 8-13 cycles per second. There is an absence of sleep spindles, K complexes and vertex sharp waves. Muscle tone reaches its lowest level although transient increases in this tonic activity may occur. Rapid eye movements might be absent in this stage as long as the other requirements ofthe stage were met. Intervals of less than 3 minutes between sleep spindles were termed stage 2 regardless of muscle tone level if there were no rapid eye movements or movement arousals. Stage W{u'akejiihies-:)—8-13 cycles per second and/or low voltage mixed frequency waves, rapid eye movements, possibly eye blinks, and high muscle tone. Normal sleep cycle: A normal sleep cycle is approximately 90-120 minutes long and is characterized by the progression of stages from stage i-2-3-4-3-2-stage REM. An uninterrupted period of 90-120 minutes is required to complete a sleep cycle. Behaviour related to sleep deprivation: Behaviour observed by the investigator and/or recalled by the patient as an inexplicable experience, such as: mumbling; slurred and rambling speech; disordered thinking; demand for more attention than usual; exaggerated anger when attention is not given; frequent
B. A. Hilton
EMG
20/iV
EEG EOG
|
1 second
1 second
FIGURE 3 Stages of sleep using electroencephalogram (EEG), muscle tone (UMG), and eye movement (EOG) recordings
A Stage W (wakefulness)—the EEG contains alpha activity and/or low voltage, mixed frequency activity. Rapid eye movements and high muscle activity are present B Stage I—a relatively low voltage mixed frequency EEG without rapid eye movements C Stage 2—12-14 cycles per second sleep spindles (underlined) and K complexes (arrow) on a background of relatively low voltage, mixed frequency EEG activity D Stage 3—moderate amounts of higli amplitude, slow wave activity E Stage 4—-large amounts of high amplitude, slow wave activity F Stage REM—a relatively low voltage, mixed frequency EEG in conjunction with episodic REMs and low amplitude EMG
Patients' sleep in a respiratory intensive care tuiit complaints and arguments; sensory disturbance; diplopia; visual illusions or hallucinatiotis; auditory hallucinations; nightmares; disorientation; delusions; paranoia; motor impairment; hyperactivity; and restlessness. Definite sleep-disturbing factor: any factor which wakens the patient trom any stage of sleep or changes the level toward wakefulness. Possible sleep-disturbing factor: any factor which may have kept the patient awake or prevented him from obtaining uninterrupted sleep patterns.
Sample To be eligible for inclusion in the sample the patients were eighteen years of age or over, conscious and rational, able to see, hear, and comprehend the English language, agreed to participate in the study, were not sufFeritig from a drug overdose, head injury, or any neurological problem which would affect the sleep recordings, and did not have a cardiac pacemaker. Permission from their attending physician was also obtained. Ten subjects constituted the study sample, varying in age from 34-81 years. All patients had respiratory insufficiency although their primary medical diagnoses varied. Data were incomplete for four patients in areas of continuous 48-hour recording, observation, or interview. The fnidings must be interpreted in the light ofthe fact that only a small number of patients was studied. There is a possibility that an observer's presence at the patient's bedside may have altered the fmdings to promote more or less sleep. Six observers were involved in collecting the data.
Method of scoring sleep stages Frequencies, amplitudes and wave patterns were considered for the EEG, EOG and EMG channels in identifying and scoring sleep stages, the characteristics of which were given in the defmitiotis. One page of record was twelve inches long and was called an epoch. At a paper speed of fifteen millimetres per second, an epoch occupied twenty seconds. All recordings were analysed by hand by the investigator. Each epoch was assigtied a single stage score based on the stage which predominated in that epoch.
Reliability cbeck A pretest was done on one patient. The investigator also recorded her own sleep by the same methods in the laboratory for one night, to determine whether the patient was being exposed to any additional discomforts by participating in the study. It was concluded that the patient was not being exposed to additional discomforts. The investigator's night record and a 24-hour period of a subject s record were checked for reliability of scoring sleep stages by a neurosurgeon involved in sleep studies,
459
46o
B. A. Hiltoti
THE FINDINGS Quantity of sleep A comparison of tlic subjects' nonnal sleep pattems and the norms cited in the literature indicated that patients had less total sleep time than normally and that the percentages of time in the sleep stages were not that of the normal cycle. Total sleep time ranged from six minutes to i3'3 hours during a 24-hour period (see Table i). Only 50-60% of the sleep occurred during the night period as contrasted TABLE I
Quantity of steep during 24-liour periods atid night periods Xorinal hours sleepl24 hours as reported hy subjects
Subject
'iota! slee[ hours
First night
Second 24 hotirs 3-3
I-irsI 24
Second night
1
,s
5-9
2-9
4 5
9
2-3
6-.S-S-5
3-0 o-t
0
2-6
6
*
7-0
2-0
7 9
S-5t
5-9
5-0
S-4 6-9
6-8 8
17
13
13-3
4-6
8-0
5-3
2-6
5-8
37 3-3 47 3-5
TOO-O
49-1
roo-Q
60-4
10
Average Percentage
2-2
4-0
41 9-2
2-3 4T
* Patient deceased I Includes a 2-hoiir nap
to almost 100% of that they normally experienced at home. Table 2 compares the predictable percentage stage time to the subjects. Stage i predominated to the deprivation of all other stages, especially stage 4 (deep sleep) and REM (dream sleep). Analgesics and sedatives tended to promote stages i and 2 sleep and at the same time there was decrease in the other stages. TABLE 2
Stage I
Comparison of'iwrntal' stage percentages to stihject stage percentages Nortital stage % * Middle-aged and elderly \'ou>ig adult differences
5
" > / sleep stages
First 24 hours
Second 24 hours
49 4t 7
43
32
2
.SO-55
3
10
4
iO
0-4
0-1
4-5
20-25
18-2.S
3-6
6-0
REM
* Source of the normals are from Kales & Kales (1970) p. 2234.
14
461
Patients' steep in a respiratory intensive care unit
Stage W
Hour (time) 1 (/5;5)
21 IB/51
912315)
10:00/51
3(1? 15]
4[l8r5)
6('9f5l
REM 1 2 3 4 W
Valium 2 mg 15IO5'SI
16(05/51
22{I2I5]
23113 IS)
245I
37(03/5)
3B
