Sleep in the ICU . . . It’s Complicated!

Authored by: Peggy Pilon, BSN, MS, RN.

The importance of sleep and sleep health is a hot topic today. Sleep is a complex process that is influenced by multiple biological and environmental factors, and there is growing evidence that sleep disturbances are associated with several adverse outcomes. The impact of sleep deprivation in critically ill patients is gaining more attention, due to the link between sleep loss and ICU-acquired delirium.

Why do we sleep??

Dr. Matthew P. Walker, PhD is a professor of neuroscience and psychology at the University of California, Berkeley, and he has spent numerous years studying the impact of sleep on human health. Dr. Walker’s bestseller, Why We Sleep, established him as one of the leading experts in the science of sleep. In his book, he outlines the importance of sleep.

Dr. Walker describes sleep as a state of reduced mental and physical activity, in which consciousness is altered and sensory activity is inhibited to a certain extent. During sleep, there is a decrease in muscle activity, and interactions with the surrounding environment are significantly reduced. It is important to note that sleep is different from wakefulness in terms of the ability to react to stimuli; sleep still involves active brain patterns. During natural sleep, the body and brain go through different stages, including Light NREM (non-Rapid Eye Movement), deep NREM,  and REM (Rapid Eye Movement) sleep.

Sleep Stages

NREM Light sleep is the initial stage of the sleep cycle, and it is characterized by slow eye movement and a decrease in muscle activity. This is followed by NREM Deep sleep, which is necessary for physical restoration and growth. During this stage, the body repairs and regenerates tissues, and builds bone and muscle. Dr. Walker discusses how during NREM sleep, the glial cells (cells in the brain that help neurons function) shrink approximately 60%, thereby allowing the cerebrospinal fluid to flush out amyloid proteins. The presence of amyloid proteins is associated with Alzheimer’s disease and is toxic to neurons; thus, sleep plays an important role in reducing one’s risk for diseases like Alzheimer’s.

REM sleep, or rapid eye movement sleep, is the final stage of the sleep cycle, and it is important for cognitive function, memory consolidation, and emotional well-being. During REM sleep, the brain is highly active and dreams often occur. As we sleep, most of the body’s systems are in an anabolic state, (where the body is building up protein and fats), which helps to restore and enhance the function of the endocrine and immune systems. 

The average length of the first NREM-REM sleep cycle is 70 to 100 minutes of uninterrupted sleep. The American Academy of Sleep Medicine and the Sleep Research Society recommends that adults get at least 7 hours of uninterrupted sleep each night to promote optimal health.

Circadian Rhythms

Another important aspect of sleep is the biological clock that regulates our sleep, known as circadian rhythms. Circadian rhythms are 24-hour cycles that are part of the body’s internal clock, running in the background to carry out essential functions and processes. Circadian rhythms work by helping to make sure that the body’s processes are optimized at various points during a 24-hour day.

One of the most important and well-known circadian rhythms is the sleep-wake cycle. The sleep-wake cycle is highly influenced by the light and darkness in our environments. During the day, light exposure causes the suprachiasmatic nucleus (SCN) within the hypothalamus (a region in the brain) to send signals that generate alertness and help keep us awake and active. As night falls, the SCN initiates the production of  melatonin, a hormone that promotes sleep. The hypothalamus continues transmitting signals that help us stay asleep through the night. It is important to recognize that the SCN is highly sensitive to light, so exposure to artificial light during a normal night phase will be disruptive to the body’s normal day-night circadian rhythms. This will cause a person to be awake during the night, when they were normally supposed to be getting restorative sleep. Experts advise limiting light before bed by dimming the lights and placing electronic devices out of the bedroom.

Sleep (Or Lack Thereof) in the ICU

As we look at sleep and the care of the ICU patient, we find many opportunities for improvement. Nursing care of the critically ill does not change depending upon the time of day. ICU patients range from requiring every ~15 minute vital sign monitoring until stable, to vital sign monitoring every 2 to 4 hours regardless of time of day. Other required round-the-clock nursing care includes: blood draws for lab tests, multiple medications and IV infusion administration, wound care, line/tube care, diagnostic tests, mechanical ventilation/oxygen support, and total body repositioning every two hours. It is no wonder that sleep disturbances in ICU patients have been studied worldwide for over 30 years. With all of these distractions, how can patients be expected to get quality sleep? 

That’s not to mention the environmental conditions that adversely affect the quality and quantity of sleep for ICU patients. Patients and their families routinely share that the noise generated by alarming patient monitors and other medical devices make it difficult for patients to sleep. Many describe the common experience of just dozing off to sleep, only to be awakened by a beeping false alarm. It is well documented in the literature that noise plays a significant role in sleep interruption (11.5 – 17% of awakenings). It is also noted that the introduction of “white noise” into the ICU environment has proven unsuccessful in reducing the magnitude of changing noise levels

Besides noise, too much light or light at the wrong time is another environmental factor affecting sleep in the ICU. Light is often required to assess and care for patients, which in turn makes it difficult to sleep through routine nursing care. Even though ICU night nurses do their best to group their nursing care and use the minimum amount of light, sleep is still disrupted. 

Sedation is NOT sleep

It’s no wonder why critically ill patients are exhausted, especially when they find themselves in an ICU with noisy alarms, frequent vital signs checks, and bright patient rooms. Clinicians do their best to comfort them, but end up reaching for the only tool left in their toolbox…sedation. Most critically ill patients experience some degree of pain and discomfort while hospitalized in the ICU. In addition, many supportive therapies such as mechanical ventilation, naso-gatric tubes, invasive cardiac monitoring, and urinary catheters make it very difficult to rest/sleep normally. It would be easy to assume that sedatives and analgesics are the answer to getting sleep in the ICU. Or that because your patient is sedated, that they are gaining restorative sleep. Even though sedatives and opiates are widely used to treat pain and facilitate sleep, they do not produce appropriate natural sleep and instead can aggravate the problems associated with inadequate restorative sleep.

Sleep in the ICU: Things Need to Change NOW

So what can we do to improve sleep in the ICU? It’s important for healthcare leaders to put themselves in the “patient’s shoes” to address these issues. It’s not hard to image that these noisy ICU environments can feel like torture to our vulnerable patients. We always need to remember that treatment of the patient’s critical condition comes first. However, as soon as ICU patients are more stable, their need for restorative sleep must become more of a priority. The move to minimize sedation and treat pain appropriately to decrease ICU-induced delirium continues to be a focal point in ICU care, because sedation is not sleep. We need to support “dark” and “lights out” rest periods to promote as natural sleep as possible.

To date, managing the environmental noise remains our biggest opportunity to improve the sleep and care of the ICU patient. As vital sign monitoring devices continue to beep with non-actionable alarms that keep patients awake, we need to look to AI technologies, such as CalmWave, to manage this bedside “noise pollution.” We at CalmWave use AI technology to make every alarm an actionable alarm for the nurse to respond to. Fewer alarms means a quieter environment that can help patients sleep more and potentially heal and return home faster. Quieter environment…more sleep…faster recovery…that’s what patients want and need. Contact us to learn how we can help you turn your ICU into a more optimal place for healing and recovery.

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