Circadian distribution of sleep phases after major abdominal surgery
01 Jan 2008-BJA: British Journal of Anaesthesia (Oxford University Press)-Vol. 100, Iss: 1, pp 45-49
TL;DR: Patients have significantly increased REM sleep, LS, and reduced time awake during the daytime period after surgery compared with before surgery, suggesting disturbances in the circadian regulation of the sleep-wake cycle may be involved in the development of postoperative sleep disturbances.
Abstract: Background It is believed that the severely disturbed night-time sleep architecture after surgery is associated with increased cardiovascular morbidity with rebound of rapid eye movement (REM). The daytime sleep pattern of patients after major general surgery has not been investigated before. We decided to study the circadian distribution of sleep phases before and after surgery. Methods Eleven patients undergoing elective major abdominal surgery were included in the study. Continuous ambulatory polysomnographic monitoring was made 24 h before surgery and 36 h after surgery, thus including two nights after operation. Sleep was scored independently by two blinded observers and the recordings were reported as awake, light sleep (LS, stages I and II), slow wave sleep (SWS, stages III and IV), and REM sleep. Results There was significantly increased REM sleep ( P =0.046), LS ( P =0.020), and reduced time awake ( P =0.016) in the postoperative daytime period compared with the preoperative daytime period. Five patients had REM sleep during the daytime after surgery. Three of these patients did not have REM sleep during the preceding postoperative night. There was significantly reduced night-time REM sleep for two nights after surgery compared with before surgery ( P =0.001). Conclusions Patients have significantly increased REM sleep, LS, and reduced time awake during the daytime period after surgery compared with before surgery. Disturbances in the circadian regulation of the sleep–wake cycle may be involved in the development of postoperative sleep disturbances.
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TL;DR: It is concluded that the pathogenesis of POCD is multifactorial and future studies should focus on evaluating the role of postoperative sleep disturbances, inflammatory stress responses, pain and environmental factors.
Abstract: There is evidence that postoperative cognitive dysfunction (POCD) is a significant problem after major surgery, but the pathophysiology has not been fully elucidated. The interpretation of available studies is difficult due to differences in neuropsychological test batteries as well as the lack of appropriate controls. Furthermore, there are no internationally accepted criteria for defining POCD. This article aims to provide an update of current knowledge of the pathogenesis of POCD with a focus on perioperative pathophysiology and possible benefits achieved from an enhanced postoperative recovery using a fast-track methodology. It is concluded that the pathogenesis of POCD is multifactorial and future studies should focus on evaluating the role of postoperative sleep disturbances, inflammatory stress responses, pain and environmental factors. Potential prophylactic intervention may include minimal invasive surgery, multi-modal non-opioid pain management and pharmacological manipulation of the inflammatory response and sleep architecture.
267 citations
Cites background from "Circadian distribution of sleep pha..."
...The rebound REM sleep leads to labile haemodynamics and ventilatory changes with a decrease in hypoxic drive with implications for cardiovascular morbidity.(33,35,36) Acetylcholine and adenosine play an important role in mediating alertness and wakefulness, and the elderly are more susceptible to unwanted...
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...A substantial decrease in REM sleep occurs on the first postoperative night,(35,36) followed by a profound rebound phenomenon on the second to fourth postoperative night, where REM sleep increases in both intensity and amount.(33,35,36) The rebound REM sleep leads to labile haemodynamics and ventilatory changes with a decrease in hypoxic drive with implications for cardiovascular morbidity....
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TL;DR: Combination of an obstructive sleep apnea screening tool preoperatively (SACS) and recurrent PACU respiratory events was associated with a higher oxygen desaturation index and postoperative respiratory complications.
Abstract: Background: Patients with obstructive sleep apnea are at risk for perioperative morbidity. The authors used a screening prediction model for obstructive sleep apnea to generate a sleep apnea clinical score (SACS) that identified patients at high or low risk for obstructive sleep apnea. This was combined with postanesthesia care unit (PACU) monitoring with the aim of identifying patients at high risk of postoperative oxygen desaturation and respiratory complications. Methods: In this prospective cohort study, surgical patients with a hospital stay longer than 48 h who consented were enrolled. The SACS (high or low risk) was calculated; all patients were monitored in the PACU for recurrent episodes of bradypnea, apnea, desaturations, and pain‐sedation mismatch. All patients underwent pulse oximetry postoperatively; complications were documented. Chi-square, two-sample t test, and logistic regression were used for analysis. The oxygen desaturation index (number of desaturations per hour) was calculated. Oxygen desaturation index and incidence of postoperative cardiorespiratory complications were primary endpoints. Results: Six hundred ninety-three patients were enrolled. From multivariable logistic regression analysis, the likelihood of a postoperative oxygen desaturation index greater than 10 was increased with a high SACS (odds ratio 1.9, P < 0.001) and recurrent PACU events (odds ratio 1.5, P 0.036). Postoperative respiratory events were also associated with a high SACS (odds ratio 3.5, P < 0.001) and recurrent PACU events (odds ratio 21.0, P < 0.001). Conclusions: Combination of an obstructive sleep apnea screening tool preoperatively (SACS) and recurrent PACU respiratory events was associated with a higher oxygen desaturation index and postoperative respiratory complications. A two-phase process to identify patients at higher risk for perioperative respiratory desaturations and complications may be useful to stratify and manage surgical patients postoperatively. PATIENTS with obstructive sleep apnea (OSA) are at risk for perioperative morbidity, and many patients who present for surgical procedures may have undiagnosed OSA. 1–5 In 1993, approximately 4% of men and 2% of
236 citations
TL;DR: One half of unanticipated tracheal intubations in a period of 30 days occurred within the first 3 days after nonemergent, noncardiac surgery and were independently associated with a 9-fold increase in mortality.
Abstract: Background Although the risk of hypoxemia is greatest during the first 72 h after surgery, little is known of the incidence of respiratory failure during this period. The authors studied the incidence and predictors of unanticipated early postoperative intubation (within 3 days) and its role in mortality. Methods A total of 222,094 adult patients undergoing nonemergent, noncardiac surgery in the American College of Surgeons-National Surgical Quality Improvement Program database were studied to determine the incidence and independent predictors of unanticipated early postoperative intubation. A risk-class model was developed and subsequently validated in 109,636 patients. Results Overall, 2,828 of 5,725 (49.4%) unanticipated tracheal intubations in a period of 30 days occurred within the first 3 days after surgery. The incidence of unanticipated early postoperative intubation was 0.83-0.9% in the derivation and validation cohorts. Independent predictors of unanticipated early postoperative intubation included current ethanol use, current smoker, dyspnea, chronic obstructive pulmonary disease, diabetes mellitus needing insulin therapy, active congestive heart failure, hypertension requiring medication, abnormal liver function, cancer, prolonged hospitalization, recent weight loss, body mass index less than 18.5 or ≥ 40 kg/m, medium-risk surgery, high-risk surgery, very-high-risk surgery, and sepsis. Unanticipated early postoperative intubation was an independent predictor of 30-day mortality, with an adjusted odds ratio of 9.2. Higher risk classes were associated with increasing incidence of unanticipated early postoperative intubation and death. Conclusions One half of unanticipated tracheal intubations in a period of 30 days occurred within the first 3 days after nonemergent, noncardiac surgery and were independently associated with a 9-fold increase in mortality. The authors present a validated perioperative risk class index for determining risk of unanticipated early postoperative intubation.
164 citations
TL;DR: Postoperatively, sleep architecture was disturbed and AHI was increased in both OSA and non-OSA patients and breathing disturbances during sleep were greatest on postoperative N3.
Abstract: Background:Anesthetics, analgesics, and surgery may profoundly affect sleep architecture and aggravate sleep-related breathing disturbances. The authors hypothesized that patients with preoperative polysomnographic evidence of obstructive sleep apnea (OSA) would experience greater changes in these p
141 citations
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...OSA 38 34 (23, 55)† 3 (0, 39)* 45 (20, 66)† 37 (15, 58)† 33 (20, 46)†...
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TL;DR: Patients with a higher preoperative AHI were predicted to have a higher postoperatively AHI and slow wave sleep percentage was inversely associated with postoperative A HI and central apnea index.
Abstract: Introduction:The knowledge on the mechanism of the postoperative exacerbation of sleep-disordered breathing may direct the perioperative management of patients with obstructive sleep apnea The objective of this study is to investigate the factors associated with postoperative severity of sleep-diso
132 citations
References
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TL;DR: Analyses of the (nonadditive) interaction of the circadian and sleep-dependent components of sleep propensity and sleep structure revealed that the phase relation between the sleep-wake cycle and the circadian pacemaker during entrainment promotes the consolidation of sleep and wakefulness and facilitates the transitions between these vigilance states.
Abstract: The role of the endogenous circadian pacemaker in the timing of the sleep-wake cycle and the regulation of the internal structure of sleep, including REM sleep, EEG slow-wave (0.75-4.5 Hz) and sleep spindle activity (12.75-15.0 Hz) was investigated. Eight men lived in an environment free of time cues for 33-36 d and were scheduled to a 28 hr rest-activity cycle so that sleep episodes (9.33 hr each) occurred at all phases of the endogenous circadian cycle and variations in wakefulness preceding sleep were minimized. The crest of the robust circadian rhythm of REM sleep, which was observed throughout the sleep episode, was positioned shortly after the minimum of the core body temperature rhythm. Furthermore, a sleep-dependent increase of REM sleep was present, which, interacting with the circadian modulation, resulted in highest values of REM sleep when the end of scheduled sleep episodes coincided with habitual wake-time. Slow-wave activity decreased and sleep spindle activity increased in the course of all sleep episodes. Slow-wave activity in non-REM sleep exhibited a low amplitude circadian modulation which did not parallel the circadian rhythm of sleep propensity. Sleep spindle activity showed a marked endogenous circadian rhythm; its crest coincident with the beginning of the habitual sleep episode. Analyses of the (nonadditive) interaction of the circadian and sleep-dependent components of sleep propensity and sleep structure revealed that the phase relation between the sleep-wake cycle and the circadian pacemaker during entrainment promotes the consolidation of sleep and wakefulness and facilitates the transitions between these vigilance states.
1,241 citations
TL;DR: The orexin neurons in the lateral hypothalamus may help stabilize the sleep/wake system by exciting arousal regions during wakefulness, preventing unwanted transitions between wakefulness and sleep.
Abstract: A good night's sleep is one of life's most satisfying experiences, while sleeplessness is stressful and causes cognitive impairment. Yet the mechanisms that regulate the ability to sleep have only recently been subjected to detailed investigation. New studies show that the control of wake and sleep emerges from the interaction of cell groups that cause arousal with other nuclei that induce sleep such as the ventrolateral preoptic nucleus (VLPO). The VLPO inhibits the ascending arousal regions and is in turn inhibited by them, thus forming a mutually inhibitory system resembling what electrical engineers call a "flip-flop switch." This switch may help produce sharp transitions between discrete behavioral states, but it is not necessarily stable. The orexin neurons in the lateral hypothalamus may help stabilize this system by exciting arousal regions during wakefulness, preventing unwanted transitions between wakefulness and sleep. The importance of this stabilizing role is apparent in narcolepsy, in which an absence of the orexin neurons causes numerous, unintended transitions in and out of sleep and allows fragments of REM sleep to intrude into wakefulness. These influences on the sleep/wake system by homeostatic and circadian drives, as well as emotional inputs, are reviewed. Understanding the pathways that underlie the regulation of sleep and wakefulness may provide important insights into how the cognitive and emotional systems interact with basic homeostatic and circadian drives for sleep.
364 citations
TL;DR: There is an endogenous circadian rhythm of REM sleep propensity which is closely coupled to the body temperature rhythm and is capable of free-running with a period different from both 24 hr and the average period of the sleep-wake cycle.
Abstract: Ten male subjects were studied for a total of 306 days on self-selected schedules Four of them developed bedrest-activity cycle period lengths very different from 24 hr (mean = 368 hr) despite the persistence of near-24-hr oscillations in other physiologic functions, including that of body temperature (mean = 246 hr) The percentage of sleep time spent in REM sleep varied significantly with the phase of that near-24-hr body temperature cycle The peak in REM sleep propensity (RSP) occurred on the rising slope of the average body temperature curve, coincident with the phase of peak sleep tendency This was associated with a significantly increased REM episode duration and shortened REM latency (including sleep-onset REM episodes), but without a significant change in the REM-NREM cycle length We conclude that there is an endogenous circadian rhythm of REM sleep propensity which is closely coupled to the body temperature rhythm and is capable of free-running with a period different from both 24 hr and the average period of the sleep-wake cycle
346 citations
TL;DR: The grossly abnormal sleep pattern observed in patients after major non-cardiac surgery may suggest some fundamental disarrangement of the sleep-wake regulating mechanism.
Abstract: Sleep was studied in nine patients for two to four days after major non-cardiac surgery by continuous polygraphic recording of electroencephalogram, electrooculogram, and electromyogram. Presumed optimal conditions for sleep were provided by a concerted effort by staff to offer constant pain relief and reduce environmental disturbance to a minimum. All patients were severely deprived of sleep compared with normal. The mean cumulative sleep time (stage 1 excluded) for the first two nights, daytime sleep included, was less than two hours a night. Stages 3 and 4 and rapid eye movement sleep were severely or completely suppressed. The sustained wakefulness could be attributed to pain and environmental disturbance to only minor degree. Sleep time as estimated by nursing staff was often grossly misjudged and consistently overestimated when compared with the parallel polygraphic recording. The grossly abnormal sleep pattern observed in these patients may suggest some fundamental disarrangement of the sleep-wake regulating mechanism.
317 citations
TL;DR: It is concluded that anesthesia with upper abdominal surgery leads to a severe disruption of nocturnal sleep followed by the release of highly intense REM sleep about the middle of the first postoperative week.
Abstract: Characteristics of nocturnal sleep were investigated in six patients after anesthesia and cholecystectomy and in another six after anesthesia and gastroplasty. All night polysomnographic recordings were obtained while each patient slept in a private surgical ward room through two nights before and five or six nights after operation. Anesthesia included thiopental, N2O, isoflurane, and fentanyl. Postoperative analgesia was provided with parenteral morphine. Other aspects of care were routine. Nocturnal sleep was markedly disturbed after both surgical procedures. Throughout the operative night and subsequent one or two nights, sleep was highly fragmented with the usual recurring cycles of sleep stages completely disrupted. Slow wave sleep was suppressed and rapid eye movement (REM) sleep virtually eliminated. During the following 2-4 nights, as other aspects of sleep recovered, REM sleep reappeared and then increased to greater than the preoperative amount. This increased REM sleep was marked by a heavy density of eye movement activity along with frequent patient reports of unusually distressing dreams or vivid nightmares. It is concluded that anesthesia with upper abdominal surgery leads to a severe disruption of nocturnal sleep followed by the release of highly intense REM sleep about the middle of the first postoperative week.
301 citations