Cardiac arrest: long-term cognitive and imaging analysis
Introduction
The progressive improvement of emergency healthcare has increased the percentage of cardiac arrest (CA) survivors. Nevertheless, there are about 30–50% of patients that remain with different degrees of anoxic encephalopathy and with diverse levels of impairment in daily life activities [1]. Although the ultimate goal of cardiopulmonary resuscitation (CPR) is to return the patient to a pre-arrest functional level for a sustained period of time [2], [3], evaluation of outcome after CA focuses mainly on survival, less emphasis being given to other outcome measures.
Although cognitive impairment, particularly memory dysfunction, has been reported in about 20–50% [4], [5], [6] of CPR survivors, there are few long-term analyses of neuropsychological sequelae and their impact on cognitive and mood dysfunction of patients, families and society [7], [8], [9], [10].
Neurological and neuropsychological outcomes influence health related quality of life (HR-QOL), a multivariate concept progressively more used in the outcome analysis of CA [3]. Even so, HR-QOL is probably not the best measurement to analyze personal and social impact of cognitive dysfunction due to brain anoxia, as higher cognitive impairment and mood changes can lead to an underscoring of difficulties by the patient [10]. Currently recommended neurological outcomes in the Utstein reporting style [11], [12], [13] focus on Cerebral Performance Categories (CPC) defined in a 1–5 scale with 1, being good cerebral performance and 5, brain death. Although CPC classification is easy to use, it does not detail sufficiently higher cognitive function impairment. For example grade 3: ‘includes a wide range of cerebral abnormalities from independent existence to paralysis and able to communicate minimally’. There could be important social and personal differences among patients classified as CPC 1: ‘good cerebral performance’ and as CPC 2: ‘moderate cerebral disability’. In this latter group, patients must be conscious and have sufficient cerebral function for part-time work in a sheltered environment or the independent activities of daily life, but they can present important neurological deficits such as hemiplegia, ataxia, dysarthria, dysphagia, seizures and permanent memory or mental changes.
Notwithstanding the widely known neurophysiologic abnormalities caused by brain anoxia, there is still much uncertainty about the mechanisms of neuroplasticity following cerebral anoxia in humans [14] and the cognitive rehabilitation potential.
This study has two main objectives: (i) to evaluate the extension and cognitive dysfunction characteristics of CA survivors from our ongoing program of evaluation of HR-QOL; (ii) to analyze the contribution of neuropsychological testing and cerebral imaging to the development of a long-term classification of neurological impairment.
Section snippets
Subjects and procedure
All the nineteen CA adult patients admitted to an eight-bed medical/surgical (ICU) of a tertiary care hospital from April 1997 to December 2000, alive at 6 months after ICU discharge attended a follow-up interview [15]. Eleven of these patients lived in the geographical area of the hospital and agreed to participate in a more extensive evaluation. Patient and family interviews, neurological examination, cognitive testing and computerized tomography (CT) scan were performed in all patients. CA
Global evaluation and interrater reliability
The reliability of classification was assessed considering the CT scan, the neurological examination, the CPC and the neuropsychological overall performance.
Considering a dichotomous classification (joining affected or considerably affected patients), for nine out of the 11 patients there was complete agreement (Table 1). In patient 1M there was lack of agreement on the classification of CPC, considered as affected by two examiners and not affected by other examiner. In the eldest patient
Discussion
The neurological examination, neuropsychological testing and brain CT scan measurements assessed in 11 patients observed between 1 and 3 years after CA were in close agreement, indicating a good overall performance in six of these patients.
With reference to the prognostic value of CA variables at admission, the GCS score 3 days after CA was associated with cognitive outcome evaluated on average 22 months after CA. Four of the five remaining patients presented an abnormal GCS score and all
Acknowledgements
We thank Minal Honavar, for her review of the manuscript.
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