Sleep disturbance after major surgery is common, and some people assume anesthesia is the cause. That is probably wrong.
The “surgical stress response“, the body’s hormonal and metabolic response to the trauma of surgery, is quite profound and has an important effect on the subsequent amount and quality of sleep. The bigger the surgery, it seems, the more significant is the stress response and the accompanying sleep disturbance.
During the stress response, hormones from the pituitary gland are released, and the sympathetic nervous system is activated (adrenaline and its companion “fight or flight” hormones). Metabolic changes include increased blood sugar, and breakdown of body protein. Injured tissues release cytokines and other potent chemicals associated with inflammation.
Pain, and the medications used to treat pain, sedatives, food deprivation, fever, psychological factors, age, and a person’s usual sleep profile all affect sleep after surgery.
Pain is a major factor, in two ways. Pain decreases sleep, and, conversely, inadequate sleep exacerbates pain.
Environmental factors in the hospital (noise, observation and nursing procedures, uncomfortable temperatures, artificial light) can also limit the duration and quality of sleep. Anyone who has spent time in a hospital knows it is a busy place, beset by noise and interruption, even drama. It’s no place to get a good night’s sleep – this is especially true of conditions in Intensive Care Units.
REM (Rapid Eye Movement) sleep and Slow Wave Sleep (SWS) are important parts of the “architecture” of normal sleep. After surgery, the amount of REM sleep (associated with dreaming, and necessary for normal sleep) is decreased for 1 or 2 nights, then rebounds. Nightmares during the rebound period (around night 4) are common. SWS is also affected for the first few nights. By around 1 week most people’s sleep patterns are restored to normal, but as many as a quarter of people still are not sleeping normally at this point after major surgery. Studies of sleep patterns beyond a week after surgery do not appear to have been done.
There is evidence that general anesthesia, often blamed for a wide range of ills and unusual symptoms after surgery, is not responsible for sleep disturbance. In fact, study volunteers who underwent 3 hours of general anesthesia without surgery showed only minimal sleep disturbance afterwards, limited to the first night after the anesthesia. (Knill RL. Anesthesiology 1988 Sep;69(3):327-31).
Anesthesia – both general and regional techniques – can modify the stress response. Its possible therefore that anesthesia, particularly regional anesthesia continued into the period after surgery, could actually improve sleep but I don’t know of any studies that have tested this hypothesis.
What can be done about it
Hospitals can try to create an environment conducive to sleep, minimising interruptions, and noise, setting room temperatures for comfort.
Effective pain relief is key, and techniques using local anesthetics and some non-pharmacologic techniques are probably useful.
Minimally invasive surgery is associated with less sleep disturbance postoperatively than “open procedures” Choose minimally invasive surgery, for this and many other reasons.
Bright light during the daytime can help to restore the body’s natural rhythms (circadian) and possibly even hasten recovery (one small study – Intensive & Critical Care Nursing 2007 Oct;23(5):289-97) by mimicking the normal day/night cycle.
Reference: Rosenberg-Adamsen S. Postoperative sleep disturbances: mechanisms and clinical implications. Br J Anaesth 1996; 76: 552-559. Download article (PDF).