Outline causes and consequences of altered sleep in the ICU patient. List strategies for improvement of sleep quality in these patients.
1) Environment: Noise, light, Patient care activities (monitoring, positioning, suction etc) (These only account for 30%)
2) Pharamacological – use of benzodiazepines and narcotics
3) Gravity of illness
5) Any pre-existing cause of sleep disturbance
In a large proportion, cause of disordered sleep unknown
1) Delirium (this has an adverse effect on long term outcome).
1) Minimising noise (ear plugs)
2) Cut down lights
3) Optimal ventilatory parameters to avoid non-triggered breaths, avoiding apnoeas and episodes of desaturation
4) Atypical antipsychotics
5) Role of melatonin – needs evaluation
This topic has been of some considerable interest, considering how many articles pop up when you look up "sleep disturbance in the ICU". Much of this information has been derived from this excellent article from the The Open Critical Care Medicine Journal:
The following factors have been found to act as negative influences:
- Noise: 10-20% of wakings
- Constant harsh light; misalignment of circaian cycles - artificiasl light is of insufficient intensity to act as a zeitgeber
- Sunlight exposure is limited or nonexistant
- Erratic stimulus (eg. hourly neuro obs)
- Appropriately timed meals are replaced by tube feeding
- Regular nursing care (eg. turns) disturbs nocturnal sleep
- Sepsis decreased REM sleep by influencing melatonin secretion
- Sedatives impair normal REM sleep
- Mechanical ventilation impairs sleep
The EPA recommends no higher than 45 dB in the ICU; however, this is actually quite loud - it is "the sound level recognized internationally as an upper limit for human comfort in residential interior spaces".
The following consequences have been ascribed to sleep deprivation, though in truth there really is no way of testing that.
- Impaired immunity
- Increased use of sedatives
- Impaired sleep following sicharge from ICU
Management of sleep disturance in the ICU:
- Noise minimisation
- Light level fluctuation to model the day-night rhythm
- Minimisation of mechanical ventilation, and the use of patient-triggered modes
- Atypical antipsychotics for delirium
- Use of melatonin (the studies are too few, and too heterogeneous, to make recommendations at this stage)
Wang, Janice, and Harly Greenberg. "Sleep and the ICU." Open Critical Care Medicine Journal 6.1 (2013): 80-87.
Schwab, Richard J. "Disturbances of sleep in the intensive care unit." Critical care clinics 10.4 (1994): 681-694.
Langevoort, G., et al. "Sleep disturbances in the ICU." Critical Care 15 (2011): 1-190.
Parthasarathy, Sairam, and Martin J. Tobin. "Sleep in the intensive care unit."Applied Physiology in Intensive Care Medicine 2. Springer Berlin Heidelberg, 2012. 61-70.
Bellapart, J., and R. Boots. "Potential use of melatonin in sleep and delirium in the critically ill." British journal of anaesthesia 108.4 (2012): 572-580.