1. Delirium screening post cardiac surgery
Bijoy Saha1, Stuart Gillon2, Donald Whitaker2, Gudrun Kunst1,2.
1. King’s College, London. 2. King’s College Hospital, London.
INTRODUCTION
Delirium is an acute neurological syndrome characterised by altered cognition, perception and conscious level. It is a common sequela to cardiac surgery, with a reported incidence of between 8%[1] and 54%[2]. Delirium is associated with increased length of hospital stay, cost of care and mortality[3].
The National Institute for Clinical Excellence recommend screening for delirium in high risk patients[4]; a cohort to which cardiac surgical patients universally belong.
DSM IV criteria
Disturbance of consciousness with decreased clarity of awareness and difficulties of attention.
Change in cognition, e.g. memory deficit and disorientation or presence of perceptual abnormalities. These changes are not the result of previous or evolving dementia.
The disturbance develops over a short period of time and fluctuates.
There is evidence that the disturbance is the result of a general medical condition.
Increased risk of delirium
Precipitating
Ventilator time
Post-op infection
Prolonged operating time
Surgery
Cardio pulmonary bypass
Valve
Predisposing
Age
Cerebrovascular disease
Diabetes
AIMS
To assess adherence to national guidelines and efficacy of current practice
OBJECTIVES
To identify the means by which clinical staff at King’s College Hospital assess for the presence of delirium within the post-operative cardiac surgical population
To compare these methods with validated screening measures
3 Clinical Subtypes
Hyperactive - heightened arousal: restless, agitated or aggressive
Hypoactive – withdrawn: quiet and sleepy
Mixed
RESULTS
A total of 26 patient days were assessed. In six (26%) cases delirium was actively sought however the assessment used was not a recognised delirium screening tool. The CAM tool identified four cases of delirium (15%); three of these (75%) were not picked up by our standard practice. One patient was deemed to have delirium by nursing assessment however CAM was negative. CAM proved a practically applicable tool in this population.
METHOD
Approval was granted by the local Clinical Audit Committee. For a three week period in March 2014, patients on day 1, 2 and 3 post cardiac surgery were assessed; those admitted directly to the Intensive Care Unit were excluded. Two investigators (BS and SG) interviewed the nurse directly responsible for patient care to determine whether delirium had been actively assessed, what means had been used to assess for delirium and whether delirium was believed to be present. Subsequently, the short Confusion Assessment Method (CAM) test[5] was conducted as a formal screen.
Delirium data collection sheet
DISCUSSION
Nursing staff don’t routinely, actively assess for delirium
When they do, they utilise informal (talking to the patient) or non-delirium-specific tools (e.g. the GCS)
The CAM tool is practical and can be carried out in less than two minutes.
In our group (using CAM as the Gold Standard for identifying delirium) there were four cases (15%) of delirium; three of these (75%) were ‘missed’ by current practice.
One patient was incorrectly labelled as being delirious when their CAM suggested otherwise.
Study is limited by small number of patients and time period the data was collected
No.
Question
Yes No
Answers if yes
Question 1a
Have you looked for delirium today?
Question 1b
If yes: How have you looked for delirium?
Question 2a
Do you think the patient has delirium?
Question 2b
If yes: Why do you think they have delirium?
CONCLUSIONS
In this local audit, the incidence of delirium, as determined by the CAM tool, is in keeping with published rates. An ad hoc system of delirium assessment demonstrated poor sensitivity and specificity. We suggest the implementation of a validated delirium screening tool in the post cardiac surgical population.
REFERENCES
1. Bucerius, J., et al., Predictors of delirium after cardiac surgery delirium: effect of beating-heart (off-pump) surgery. J Thorac Cardiovasc Surg, (1): p
2. Smulter, N., et al., Delirium after cardiac surgery: incidence and risk factors. Interact Cardiovasc Thorac Surg, (5): p
3. Eeles, E.M.P., et al., Hospital use, institutionalisation and mortality associated with delirium. Age and Ageing, (4): p
4. NICE. Delirium - diagnosis, prevention and management [cited th April 2014]; Available from:
5. Wei, L.A., et al., The Confusion Assessment Method: A Systematic Review of Current Usage. Journal of the American Geriatrics Society, (5): p
Guy’s, King’s & St. Thomas’
School of Medicine