Can a patient be delirious post-surgery?

Postoperative Delirium: A Common and Serious Complication

Yes, patients can absolutely develop delirium after surgery—this is a common and serious complication that occurs in approximately 18-50% of surgical patients, with even higher rates (up to 50%) after cardiac surgery. 1

What Postoperative Delirium Is

Postoperative delirium is an acute confusional state characterized by:

• Fluctuating mental status that changes throughout the day 1
• Inattention and inability to focus 1
• Disorganized thinking or altered level of consciousness 1
• Acute onset, typically within the first few days after surgery 2, 3

This is not simply confusion—it is a medical emergency that requires immediate recognition and treatment. 4

Why This Matters: Impact on Mortality and Quality of Life

Postoperative delirium is associated with devastating outcomes that extend far beyond the hospital stay:

• Increased mortality both in-hospital and long-term 1
• Prolonged cognitive impairment lasting months to over a year after surgery 1, 5
• Reduced functional recovery and independence 1
• Longer hospital stays and increased readmission rates 1, 2
• Persistent cognitive decline, with 40% of patients not returning to baseline at 6 months 5

In cardiac surgery patients specifically, those who develop delirium show significantly lower cognitive function scores at 1 month (24.1 vs. 27.4 on MMSE) and 1 year (25.2 vs. 27.2) compared to those without delirium. 5

Who Is at Highest Risk

The most powerful risk factors for developing postoperative delirium include:

Patient-Specific Factors (Cannot Be Modified):

• Advanced age: Patients 65-85 years have 2.67 times the odds; those over 85 have 6.24 times the odds 1
• Pre-existing cognitive impairment or dementia: 3.99 times increased odds 1
• History of prior delirium: 3.9 times increased odds 1
• Male sex 1
• Low BMI (BMI <18.5): 2.25 times increased odds 1
• Lower educational level (college degree protective with OR 0.45) 1

Medical Factors:

• ASA status IV: 2.43 times increased odds 1
• Elevated preoperative C-reactive protein: 2.35-3.56 times increased odds depending on level 1
• Multiple comorbidities and polypharmacy 1
• Smoking history 1
• Living in institutional care 1

Surgical Factors:

• Longer duration of surgery/anesthesia 1
• Type of surgery (cardiac surgery has particularly high rates at ~50%) 1

Mandatory Screening Protocol

All surgical patients must be systematically screened for delirium at least once per nursing shift (every 8-12 hours) using validated tools. 1, 4

Recommended Screening Tools:

• Confusion Assessment Method (CAM) for general ward patients 1, 4
• CAM-ICU for intensive care patients 1, 4
• Intensive Care Delirium Screening Checklist (ICDSC) as alternative for ICU 4

Critical pitfall: Hypoactive delirium (quiet, withdrawn patients) is frequently missed but may have worse outcomes than hyperactive delirium. 6, 4 Do not assume a quiet patient is doing well—actively screen them.

Prevention Strategies (More Effective Than Treatment)

Prevention is far more effective than treatment once delirium develops. 3

Multimodal Opioid-Sparing Analgesia:

The JAMA Surgery guidelines recommend using: 1

• Acetaminophen
• Tramadol
• Dexmedetomidine (reduces mortality, delirium incidence, and may reduce acute kidney injury) 1
• Pregabalin or gabapentin

Rationale: Adequate pain control is essential, as uncontrolled pain is a significant risk factor for delirium. 1 However, excessive opioid use also increases risk, necessitating multimodal approaches. 1

What Does NOT Work:

• Prophylactic antipsychotics (e.g., haloperidol) do NOT reduce delirium incidence 1

Nonpharmacologic Strategies (First-Line):

• Early mobilization 1
• Reorientation techniques 1
• Sleep hygiene 6
• Avoiding hypothermia (maintain temperature >36°C) 1

Medication Management:

• Avoid benzodiazepines (strongest modifiable risk factor for ICU delirium) 7, 6
• Avoid anticholinergic medications 7
• Minimize sedation depth when possible 7

When Delirium Develops: Immediate Actions

Once delirium is identified, immediately investigate and treat underlying causes: 1, 6, 4

Systematic Evaluation:

1. Pain assessment (use validated tools even in intubated patients) 1
2. Oxygenation status (hypoxemia) 1, 6
3. Hemodynamic status (low cardiac output, shock) 1, 6
4. Infection/sepsis screening 1, 6
5. Metabolic derangements: electrolytes (especially sodium), glucose, renal function 6, 4
6. Medication review: especially benzodiazepines, opioids, anticholinergics 7, 6
7. Substance withdrawal: alcohol, benzodiazepines, opioids 6

Treatment Approach:

• Nonpharmacologic interventions remain first-line even for treatment 1
• Low-dose oral antipsychotics appear most effective when pharmacologic treatment is needed 3
• Treat the underlying cause rather than just symptoms 1, 4

Long-Term Cognitive Implications

Delirium is not just a temporary confusion—it has lasting consequences:

• Patients with postoperative delirium show a trajectory of initial severe decline followed by prolonged impairment 5
• At 1 year post-surgery, 31% of patients with delirium still have not returned to their preoperative cognitive baseline 5
• The relationship between delirium and long-term cognitive decline persists even after adjusting for baseline differences 5
• Some studies show cognitive changes persisting up to 7.5 years after surgery 7

Important distinction: Postoperative delirium (acute, days to weeks) and delayed neurocognitive recovery/postoperative cognitive disorder (weeks to months) are related but distinct entities. 7, 8 Not all patients with delirium develop long-term dysfunction, and vice versa, but delirium significantly increases the risk. 8

Key Clinical Pitfalls to Avoid

1. Failing to screen systematically: Delirium remains underdiagnosed despite available tools 4, 2, 3
2. Missing hypoactive delirium: The quiet, withdrawn patient may be more impaired than the agitated one 6, 4
3. Attributing symptoms to dementia: Always investigate for acute, reversible causes 4
4. Using prophylactic antipsychotics: No evidence of benefit 1
5. Inadequate pain control: Undertreating pain increases delirium risk more than using potentially deliriogenic medications 1