Patient Safety Tip of the Week
August 31, 2010 Postoperative Delirium
While we were preparing our August 17, 2010 Patient Safety Tip of the Week “Preoperative Consultation – Time to Change” we came across a good article on postoperative delirium (Mantz 2010) in the anesthesiology literature. We’ve previously discussed extensively the issue of postoperative delirium (see our October 2008 back-to-back columns “Managing Delirium” and “Preventing Delirium” and our March 31, 2009 Patient Safety Tip of the Week “Screening Patients for Risk of Delirium” and our January 26, 2010 Patient Safety Tip of the Week “Preventing Postoperative Delirium”). In those prior columns we’ve discussed the incidence of postoperative delirium and the serious long-term effects and the cost burden of delirium. A recent meta-analysis (Witlox 2010) confirmed the significant risks of death, institutionalization, and dementia in patients discharged after a bout of delirium.
But the Mantz article does a nice job of summarizing some of the practical aspects of preventing, identifying and managing postoperative delirium. It includes a case report (with the nuance that the patient also has a second discrete episode of delirium), and a good description of the clinical features of delirium and the tools used to help identify it. They note that the CAM-ICU may be inferior to some of the other tools in patients in the PACU (remember, their perspective is that of the anesthesiologist). They have a thorough discussion of the causes and precipitating factors, stressing some that are especially likely to be present in the PACU (eg. pain from bladder distension, hypoxemia related to residual neuromuscular relaxation, residual effects of anesthetic agents or sedating agents or anticholinergic agents). In their case they suspect the initial episode of delirium was related to occult infection (it was a clue she had peritonitis) and a second episode several days later may have been related to benzodiazepine withdrawal. Potential pathophysiological mechanisms underlying delirium are discussed, including the potential influence of many of the drugs used perioperatively on some of the postulated neurotransmitter abnormalities in delirium. They also discuss many of the components of a multimodality approach that is discussed below in more detail. And they provide the view of the geriatrician (one of the authors is a geriatrician), which stresses the relationships of delirium to dementia and depression and the issues of physical and cognitive autonomy and activities of daily living.
In the prior columns we noted above we have discussed identification of risk factors for postoperative delirum. The most salient predictors of postoperative delirium are the presence of dementia or disordered executive function. Those previous columns noted some of the validated prediction tools that can be used but often you can screen for delirium risk using simple tests like the MMSE or the clock drawing test. Our August 17, 2010 Patient Safety Tip of the Week “Preoperative Consultation – Time to Change” also discussed the importance of preoperative assessment for vision or hearing impairment, thorough review of the patient’s medications, and preparation of the patient and family/caregivers for the possibility of delirium.
NICE has just published a 662-page guidance “DELIRIUM: diagnosis, prevention and management” that is probably the most comprehensive single-source document available on all aspects of delirium. Fortunately, the important lessons have been distilled into a much more manageable summary document and a recent BMJ issue had an even briefer summary. The most important recommendation from the NICE guidance is: “THINK DELIRIUM”. Basically, we need a high index of suspicion in patients with risk factors for delirium and constant awareness of factor that might precipitate delirium and then constant vigilance to identify it early and manage it effectively.
NICE identifies 4 risk factors for delirium as really standing out:
- Age 65 or older
- Cognitive dysfunction or dementia
- Current hip fracture
- Any severe illness
They stress, both at presentation and throughout the patient’s course, asking about and observing for signs of change in behavior or fluctuations in behavior. Family or caregivers may first point these out. In particular, the hypoactive form of delirium may be the hardest to detect. Look also for changes in cognitive function, perception, physical function, and social behavior. While we typically think about confusion, hallucinations, delusions, agitation, restlessness, and sleep disturbances as signs of delirium, those with hypoactive delirium may have poor concentration, slowed responses, reduced mobility and reduced movements, changes in appetite, and social withdrawal. If signs suggestive of possible delirium are present, someone trained in delirium recognition should do a formal clinical assessment. They discuss the use of validated tools such as the CAM and CAM-ICU to screen for delirium. Note there was also just published a review (Wong 2010) on multiple different tools that are used to screen for delirium, comparing the pros and cons of each and including such practical considerations as how long the provider can spend doing such assessments. While they concur that the CAM is probably the best tool to use, they point out the simple GAR (Global Attentiveness Rating) may also be an effective tool. In the GAR you simply have a 2-minute conversation with the patient and ask yourself “how well did the patient keep his mind on interacting with you during the interview?” (you rate him on a 1-to-10 visual analogue scale).
In addition to identifying and managing underlying causes and precipitating factors (eg doing a full drug review, looking for electrolyte disturbances, hypoxemia, infection, etc.), they offer practical suggestions on managing the patient with delirium:
- Try to maintain as much consistency and familiarity of staff for the patient as possible
- Avoid moving the patient from room to room or ward to ward if possible
- Involve family, friends and familiar caregivers as much as possible
- A multicomponent intervention package (delivered by a multidisciplinary team) should be tailored to the individual needs of the patient
- Reorientation
- Reassurance
- Appropriate lighting
- Clear signage
- Consider a readily visible clock and calendar
- Assess and modify any sensory deficits (eg. hearing, vision)
- Regular visits from family and friends
- Avoid dehydration, attend to nutritional status
- Prevent constipation
- Look for and treat infection, hypoxia, etc.
- Assess for and manage pain
- Avoid catheters, restraints
- Mobilize early
- Promote natural sleep (minimize noise, avoid procedures or meds when sleeping, etc.)
- Use verbal or non-verbal de-escalation techniques where possible for the distressed patient
- Only when the above fail, consider short-term haloperidol or olanzapine, beginning in very low doses and titrating to effect on the patient’s symptoms.
They note the importance of documenting the occurrence of delirium not just in the hospital record but also in the ambulatory record, given the serious long-term associations seen with delirium.
We also refer you back to our January 26, 2010 Patient Safety Tip of the Week “Preventing Postoperative Delirium”) for a discussion on the role of depth of sedation/anesthesia, type of opioids used, and pre-op hydration management in preventing postoperative delirium.
References:
Mantz J, Hemmings H, Boddaert J. Case Scenario: Postoperative Delirium in Elderly Surgical Patients. Anesthesiology 2010. 112(1): 189-195 January 2010
Wong CL; Holroyd-Leduc J, Simel DL, Straus SE. Does This Patient Have Delirium?: Value of Bedside Instruments. JAMA 2010; 304(7): 779-786
http://jama.ama-assn.org/cgi/content/abstract/304/7/779
Witlox J, Eurelings LSM, de Jonghe JFM et al. Delirium in Elderly Patients and the Risk of Postdischarge Mortality, Institutionalization, and Dementia: A Meta-analysis. JAMA. 2010; 304(4):443-451
http://jama.ama-assn.org/cgi/content/abstract/304/4/443
NICE (National Institute for Clinical Excellence). National National Clinical Guideline Centre. DELIRIUM: diagnosis, prevention and management. Clinical Guideline 103. July 2010
full guidance:
http://www.nice.org.uk/nicemedia/live/13060/49908/49908.pdf
NICE (National Institute for Clinical Excellence). National National Clinical Guideline Centre. DELIRIUM: diagnosis, prevention and management. Clinical Guideline 103. July 2010
summary document:
http://www.nice.org.uk/nicemedia/live/13060/49909/49909.pdf
Young J, Murthy L, Westby M, Akunne A, O’Mahony R, on behalf of the Guideline Development Group.Guidelines: Diagnosis, prevention, and management of delirium: summary of NICE guidance. BMJ 341:doi:10.1136/bmj.c3704 (Published 28 July 2010)
http://www.bmj.com/content/341/bmj.c3704.extract?sid=4453e855-9632-412d-9028-89422c5ff442
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