Subsyndromal delirium after cardiac surgery

Area of Science:

• Cardiology
• Critical Care Medicine
• Neuroscience

Background:

• Delirium is a common complication after cardiac surgery.
• Subsyndromal delirium (SSD) is a less severe form of delirium.
• The clinical significance and outcomes associated with SSD require further investigation.

Purpose of the Study:

• To determine the incidence of subsyndromal delirium (SSD) in patients undergoing cardiac surgery.
• To assess the impact of SSD on clinical outcomes, including intensive care unit (ICU) and hospital length of stay, ventilation duration, and mortality.
• To differentiate SSD from clinical delirium (CD) and non-delirious (ND) states.

Main Methods:

• Prospective study involving 506 patients undergoing cardiac surgery.
• Screening for SSD and CD using the Intensive Care Delirium Screening Checklist.
• Comparison of clinical outcomes between non-delirious (ND), subsyndromal delirium (SSD), and clinical delirium (CD) groups.

Main Results:

• The incidence of SSD was 34% (150 patients), and CD was 12% (54 patients).
• Factors such as age, EuroSCORE, APACHE II, emergency operations, and aortic surgery increased from ND to SSD.
• ICU and hospital stays were longer in CD patients compared to SSD patients; ND and SSD patients had similar outcomes.
• Home discharge rates decreased from ND to SSD to CD patients.
• Mortality rates did not differ significantly between ND, SSD, and CD groups.

Conclusions:

• Subsyndromal delirium (SSD) is prevalent (34%) after cardiac surgery and largely independent of clinical delirium (CD).
• SSD is associated with a reduced rate of home discharge but does not significantly impact other clinical outcomes like mortality or length of stay compared to non-delirious patients.
• SSD does not appear to be a precursor or resolving stage of delirium based on the observed clinical outcomes.