Table 1 Accordion severity classification of postoperative complications: expanded classification [13]

1. Mild

Requires only minor invasive procedures that can be done at the bedside such as insertion of intravenous lines, urinary catheters, and nasogastric tubes, and drainage of wound infections. Physiotherapy and the following drugs are allowed: antiemetics, antipyretics, analgesics, diuretics, electrolytes, and physiotherapy.

2. Moderate

Requires pharmacologic treatment with drugs other than those allowed for minor complications, for instance, antibiotics. Blood transfusions and total parenteral nutrition are also included.

3. Severe

Invasive procedure without general anesthesia. Requires management by an endoscopic, interventional procedure or re-operation^a without general anesthesia.

4. Severe

Operation under general anesthesia. Requires management by an operation under general anesthesia.

5. Severe

Organ system failure.^b

6. Death

Postoperative death.