Prognostic Significance of Postoperative Subsyndromal Delirium

Abstract

Background Whether postoperative subsyndromal delirium (SSD) is a separate syndrome from delirium and has clinical relevance is not well understood. Objectives We sought to investigate SSD in older surgical patients and to determine its prognostic significance. Methods We performed a prospective cohort study of patients aged ≥65 years of age scheduled for noncardiac surgery. Postoperative delirium was determined using the Confusion Assessment Method. SSD was defined as the presence of at least one out of a possible 10 symptoms of delirium, as defined by the Confusion Assessment Method, but not meeting criteria for delirium. Results The number of features of SSD on the first postoperative day was associated with the subsequent development of delirium on the next day, after controlling for other risk factors. Compared to a patient with no SSD features, a patient with one SSD feature was 1.07 times more likely to have delirium on the next day (95% CI 0.42, 2.53), 2 features – 3.32 times more likely (95% CI 1.42. 7.57), and ≥ 2 features - 8.37 times more likely (95% CI 4.98, 14.53). Furthermore, there was a significant relationship between the number of features of SSD and increased length of hospital stay, and worsened functional status at one month after surgery. Conclusions SSD is prevalent in at risk surgical patients and has prognostic significance. Only one symptom of SSD was sufficient to cause a significant increase in hospital length of stay and further decline in functional status. These results suggest that monitoring for SSD is indicated in at risk patients.

Implementation of an ICU Bundle: An Interprofessional Quality Improvement Project to Enhance Delirium Management and Monitor Delirium Prevalence in a Single PICU*

“…Described by Schieveld et al (6), children with emerging delirium have an atypical presentation characterized by anxiety and disturbances in cognition, but do not develop full delirium. Future studies are needed to determine if pediatric emerging/subsyndromal delirium places children at risk for additional morbidity as described in adult literature (33). We identified 41 patients who had only one positive CAP-D(R) rating and we conceptualized these cases as emerging delirium.…”

Preoperative Risk Factors for Subsyndromal Delirium in Older Adults Who Undergo Joint Replacement Surgery

“…While subsyndromal symptoms are less severe than those seen in delirium, they are predictors for adverse outcomes, increased falls postoperatively, including increased lengths of hospital stays and long-term care admissions, and higher mortality rates (Cole, McCusker, Dendukuri, & Han, 2003; Cole et al, 2011; DeCrane, Culp, & Wakefield, 2012). Some have concluded that the presence of even one core symptom of delirium in an older adult is sufficient enough to result in an increase in the length of hospital stay and/or a decline in functional status (Shim, DePalma, Sands, & Leung, 2015). Identification of patients who are at risk for subsyndromal delirium should be made prior to surgery so prevention strategies can be initiated.…”

“…Given that one subsyndromal delirium symptom may be sufficient to cause increased lengths of hospital stay, a decline in functional status, and an increased risk for development of delirium (Shim et al, 2015), understanding the significance of subsyndromal delirium seemed essential in identifying high-risk patients for prevention and early detection to minimize adverse outcomes.…”

Subsyndromal delirium compared with delirium, dementia, and subjects without delirium or dementia in elderly general hospital admissions and nursing home residents

“…Subsyndromal delirium (SSD) is thought to represent a subthreshold state related to delirium and associated with poor posthospitalization outcomes similar to those associated with delirium [1][2][3][4][5][6][7][8]. However, it lacks a standardized definition, even in Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) [9] where it is only noted as an "attenuated delirium syndrome" without specific criteria.…”

“…Early attempts at categorical delineation of SSD required the presence of fewer symptoms than for syndromal delirium, although the specific symptoms were arbitrarily selected, did not involve severity determinations, and required only one or two symptoms that had not been empirically chosen for specificity to the delirium syndrome [1,3,6,7,[10][11][12][13].…”