Wednesday, 5 November 2014

Time to wake up to sleep deprivation in ICU

Sleep.

Its not the sexiest subject in critical care medicine.  Its not the first thing that leaps to your mind when you see your patients in ICU.  It doesn't appear on anyone's FAST HUG, or any other checklist for that matter.  When we do think about it, its usually applied only to the recovering long term patients, and not to acutely unwell people.

But how important is it?

What we do know is we do it every day.  We know we need it to restore energy and clarity of thinking.  We know most terrestrial animals do it too.

I find myself half way through my working career and am already finding that a busy night on call, with a hasty midnight journey back to the ICU, or a series of phone calls, completely disrupts my existence for days afterwards.  If I have a series of shifts like this, I feel I'm prone to respiratory viruses, at least, anecdotally.  I don't think clearly, am irrational and emotional.

So doesn't it stand to reason that our patients suffer similarly?

Sleep is largely governed by 2 parallel processes, a homeostatic mechanism that causes increasing and often precipitous fatigue, and a humeral process known as the circadian rhythm.

We know that our patients sleep poorly in ICU.  A number of factors play a part, including noise, light, pain, drugs and the disease process itself.  We know that the circadian rhythms, measured by a number of indicators, appear disturbed.  Poor sleep is associated with delirium and metabolic disturbances in critically ill.  Both are associated with complications long term such as post-traumatic stress disorder, impaired glucose control and infectious morbidity.

This month's Society of Critical Care Medicine iCritical Care podcast features a terrific interview on this subject.  Michael Weinstein chatted to Brian Gehlbach at January's SCCM congress in San Franscisco after he and a number of colleagues presented their work into this fascinating but often neglected area.  Its a thought provoking discussion and sent me searching the literature for more.

Sadly, there's currently little to guide clinicians.  But slowly, the literature is building.

A recent study by Patel et al has demonstrated the potential improvement in outcomes by implementing relatively inexpensive interventions.  This complements work done at Johns Hopkins by Kamdar et al.  Other studies have demonstrated the impact of light and noise on ICU patients and their sleep patterns.  There is almost no work on the impact of pharmacology - though we all recognise that drug induced "sleep" is currently no substitute for the real thing.

Taking this issue seriously requires significant culture change.  It requires research to tell us the factors that impact sleep and the consequences of impaired sleep.  It demands development of ventilation strategies that minimise sleep disruption.  We need to understand the way circadian rhythms interact with critical illness, medications and other interventions.  It will impact on drug administration, on nursing and medical staffing ratios, on workflow patterns, and even on the design of intensive care units themselves.

Make a start by checking out this excellent podcast

References
Patel J et al.  The effect of a multi-component multidisciplinary bundle of interventions in sleep and delirium in medical and surgical ICU patients.  Anaesthesia (2014); 69:540-49