Authors: Omoto M et al.
Anesthesia & Analgesia 141(5):998–1006, November 2025.
DOI: 10.1213/ANE.0000000000007409
Summary
This nationwide retrospective study analyzed all unplanned ICU admissions occurring directly from the operating room after elective surgery using Japan’s ICU database (JIPAD) from 2015–2022. Among nearly 142,000 elective surgical patients, 2666 (1.9%) required an unexpected postoperative ICU transfer.
These patients were very sick: the median APACHE III score was 51, 45.7% required postoperative mechanical ventilation, and 2% had a cardiac arrest before ICU arrival. Their median hospital stay was prolonged at 21 days, and overall in-hospital mortality was 3.3%.
Respiratory complications were the most common driver of unplanned ICU admission (16.5%), followed by hemorrhage (14.1%). However, cardiovascular complications—though less frequent—had the highest mortality at 6.8%. Notably, hospital mortality was higher than ICU mortality, suggesting that some patients who were unlikely to benefit from continued intensive care may have been stepped down to accommodate patients with greater need.
Unplanned ICU admissions most often followed gastrointestinal neoplasm surgeries (17.4%), with orthopedic surgeries next (11.4%). Respiratory complications were especially common in patients with underlying pulmonary disease and were present across more than half of surgery subtypes. Neurologic deterioration was predominantly seen after craniotomies for neoplasms. Anaphylaxis appeared across a wide range of surgical categories.
Overall, the findings highlight the small but clinically significant burden of unplanned ICU transfers after elective surgery, reinforcing the importance of early risk identification, vigilance for respiratory decline, and preparedness for cardiovascular instability.
What You Should Know
• 1.9% of elective surgeries required unplanned ICU admission.
• Respiratory issues were the most common cause; cardiovascular issues carried the highest mortality.
• Nearly half of patients required postoperative mechanical ventilation.
• GI cancer surgeries and orthopedic cases were most often involved.
• Mortality patterns suggest ICU triage pressures and early transitions out of the unit.
• Data support targeted perioperative risk-stratification and ICU-readiness planning.
KEY POINTS
Question: What are the patient characteristics, reasons for intensive care unit (ICU) admission, and outcomes for unplanned ICU admissions after elective surgery in Japan?
Findings: This nationwide ICU database analyzed 2666 patients and found that respiratory complications were the most common reason for unplanned ICU admission after elective surgery (n = 440, 16.5%), with an overall in-hospital mortality of 3.3% (88/2666). Cardiovascular complications had the highest mortality at 6.8% (20/294).
Meaning: Understanding the epidemiology and risk factors for unplanned ICU admissions and the risks linked to specific surgeries may be informative in establishing targeted clinical management, potentially improving perioperative patient care and outcomes in elective surgeries.
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