Appendix 1.

Medical complication the model predicts for by organ system

Complication	Definition
Cardiac complications
Air embolism	Entrainment of air into the venous circulation and heart detected by any monitoring device including Doppler, TEE, or sudden decrease in end-tidal CO₂, SpO₂, or blood pressure or air in coronary vessels on post-mortem examination
Arrest^*	Cardiac output insufficient to maintain a palpable central pulse, and requiring CPR, electroshock therapy and/or vasoactive drugs to maintain an adequate perfusion pressure.
Arrhythmia (telemetry+Tx or mc06/death)	Any cardiac rhythmthat varies frombaseline and requires either extramonitoring, drugs, consultations, or electroshock therapy, or results in hypotension or death.
CHF (new S3/JVD+rales/CXR+Tx)	An abnormality of cardiac function is responsible for the failure of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues, manifested by pulmonary edema, a new S3 gallop, jugular venous distension, rales, pleural edema or effusion, and requiring treatment.
Hypertension	SBP >180 or DBP >100 for >5 min
Hypotension (SBP/MAP <50% base, >5 min)	MAP <50% of baseline for >5 min
Infarction (mc09+enzymes/new Qs)^*	Necrosis of heart tissue as evidenced by elevated ST segments or new Q waves or new wall motion abnormality associated with elevated cardiac enzymes (troponin, CK-MB)
Inappropriate or inadequate fluid therapy	Insufficient replacement of volume with blood products, crystalloid or other colloid to maintain adequate perfusion and oxygenation of all tissues, as evidenced by inadequate urine output, low central filling pressures, elevated lactate, metabolic acidosis with pH <7.35, and/or hypotension responsive to fluids. Criteria: (1) inadequate urine output (<0.5 mL/kg/h); (2) hypotension responsive to fluid challenge; (3) elevated lactate level; (4) metabolic acidosis (pH <7.35); and/or (5) low central filling pressures
Ischemia (sx/1 mm ST 2 leads, ROMI/Tx)^*	Myocardial ischemia is a deficiency of the blood supply to the heart muscle, leading to symptoms, flat depression of the ST segment of >0.1 mV below the baseline (ie, the PR segment) and lasting >0.08 s, treatment, or rule-out MI monitoring
Thermoregulation	Temperature <35°C for >30 min
Other cardiac occurrence	Other circulation or cardiac-related occurrence
Pulmonary complications
ARDS (FiO₂>50/vent>48 h+ mc04/mr05)^*	Acute hypoxemic respiratory failure owing to pulmonary edema caused by increased permeability of the alveolar capillary barrier. Criteria: (1) FiO₂>50%; (2) ventilator support for >48 h; (3) PaO₂/FiO₂≤300 mmHg; and (4) bilateral lung infiltrates on CXR
Empyema	Purulent fluid collection in the pleural space confirmed by imaging studies and aspiration or by surgery
Hemothorax	Blood in the pleural space confirmed by imaging studies and aspiration or surgery
Pleural effusion	Excess fluid in the pleural space
Postoperative hypoxia (FiO_2>50× 48 h or supplemental O₂ ×7 d)^*	Requirement for supplemental oxygen postoperatively, with FiO₂>50% for 48 h or supplemental oxygen by nasal cannula for 7 days
Pneumonia (>38.0+Cx/CXR and Tx)	Infection of the lung parenchyma confirmed by fever, sputum or bronchial cultures, CXR, and requiring treatment
Pneumothorax	Accumulation of gas in the pleural space resulting in symptoms (tachycardia, hypotension), requiring extra surveillance (eg, repeat CXRs or pulse oximetry) or treatment (chest tube placement)
Pulmonary embolus (CTA/VQ/ angiography+Tx)^*	Sudden onset of shortness of breath, tachypnea, cyanosis, tachycardia, hypotension, or chest pain confirmed to be a imaging studies to be a pulmonary thrombus, and requiring treatment; or diagnosis made at autopsy
Respiratory arrest^*	Sudden cessation of voluntary breathing, requiring CPR or mechanical ventilation
Other respiratory	Other respiratory problem
Gastrointestinal complications
Ascites	Effusion and accumulation of serous fluid in the abdominal cavity leading discernable on physical examination or radiologic imaging (free peritoneal fluid > 25 mL), leading to symptoms, unplanned evaluation, or requiring treatment
Colitis	Inflammation of the colon manifested as diarrhea or bloody diarrhea, sepsis, abdominal pain, or toxic megacolon. Criteria: (1) Rectal discharge; (2) perineal ulceration; (3) colonoscopic and biopsy evidence of inflammation
GI bleeding (heme pos+drop Hct 10% or Tx)	Blood loss through the gastrointestinal tract, including hematemesis, melena, hematochezia, occult GI bleeding may be identified in the absence of overt bleeding by special examination of the stool (eg, guaiac testing), or symptoms of blood loss or anemia such as lightheadedness, syncope, angina, or dyspnea. Criteria: (1) Bloody vomitus or stool; (2) bleeding from the rectum; (3) Hct decrease >10%; (4) lightheadedness, syncope, angina, or dyspnea
Ileus	Abdominal distension and no passage of stool or flatus by postoperative day 3
Obstruction	Pseudo-obstruction is colonic distension in the absence of mechanical obstruction, with cecal diameter of >9 cm and air in all colonic segments on plain radiographs
Pancreatitis	Acute inflammation of the pancreaswith sudden onset of: (1) abdominal pain; (2) nausea; (3) vomiting; (4) high levels pancreas enzymes (serumamylase 3× normal)
Perforation^*	Iatrogenic perforation of the stomach, small intestine, or large intestine during the procedure or perforation later caused by implants or instrumentation. Criteria: (1) Nausea, vomiting, or ileus; (2) abdominal or groin pain and referred pain; (3) air in the abdomen on plain radiograph or CT or other imaging study; (4) abdominal distension and tenderness; or surgical finding of perforation
Peritonitis	Inflammation or infection of the peritoneum with symptoms of (1) abdominal pain and tenderness; (2) constipation; (3) vomiting; (4) moderate fever
Other GI occurrence	Other GI-related occurrence
Neurologic complications
CVA/TIA (new focal deficit or CT/MR)^*	The abrupt onset of a nonconvulsive and new focal neurologic deficit owing to a reduction of blood flow to the brain, or abnormality on imaging studies suggestive of a CNS infarct, or CNS infarction confirmed by biopsy or autopsy
Cerebral perfusion (ICP>20 or CPP <30 for >5 min)	Reduction in the flow of blood to the brain during the procedure for >5 minutes, with intracranial pressure >20 or cerebral perfusion pressure <30 mmHg
Delirium (confusion>24 h+Tx/sitter/ restraint)	Acute change in level of consciousness characterized by reduced ability to maintain attention to external stimuli, lethargy, or agitation, and disorganized thinking as manifested by rambling, irrelevant, or incoherent speech. Criteria: (1) Confusion>24 h; and (2) was not related to narcotics; and (3) patient required restraints or continuous supervision
Diabetes insipidus	Excessive urine production from reduced production or responsiveness to ADH; diagnosis can be made by relating plasma to urine osmolality, particularly in postoperative neurosurgical patients or after head trauma, where its use can permit quick differentiation of diabetes insipidus from parenteral fluid excess
Electrolyte change (Na <130/>150, K>5.5, other)	The electrolyte balance of the extracellular fluid was sufficiently changed from normal to require extra monitoring, evaluation, or treatment beyond routine postoperative care. Specifically: Na <130 or>150 or K >5.5
Meningitis (pos Cx/Bx or CT/MR and Tx)^*	Inflammation of the meninges (the pia-arachnoid) and the CSF of the subarachnoid space associated with symptoms of fever, headache, nausea/diarrhea/ abdominal pain, and confirmed by CSF cultures or biopsy, imaging studies, and requiring treatment
SAH/intracerebral hemorrhage^*	Hemorrhage in the space between the arachnoid membrane and pia matter (subarachnoid) causing compression of the brain associated with sudden headache, neurologic deficit, and confirmed with imaging studies or blood in the CSF; may also occur in the spinal cord in association with sudden back pain
Seizure	Paroxysmal event owing to abnormal, excessive, hypersynchronous discharges from an aggregate of CNS neurons with manifestations ranging from convulsive activity to experiential phenomena not discernible by an observer, confirmed by EEG or neurology consultation
Withdrawal, alcohol (history+ mn03+Tx)	A patient with history of alcohol abuse exhibits anxiety, confusion and delirium after the cessation of alcohol intake, requiring treatment
Withdrawal, narcotic	The patient exhibits symptoms of nausea and diarrhea, coughing, lacrimation, mydriasis, rhinorrhea, profuse sweating, twitching muscles, and piloerection, or “goose bumps”; mild elevations in body temperature, respiratory rate, and blood pressure after reduction or cessation of narcotic intake, with improvement in symptoms after opioid administration
Other neurologic occurrence	Other neurologic occurrence
Hematologic complications
Coagulopathy (INR>2 or platelets <50 or Fib <100)	Any disorder reducing the ability of the blood to clot: Severity 1, INR>1.5 and <2.0, or platelets <100k and >50k; severity 2, INR>2.0 and <3.0, or platelets <50k and >20k; severity 3, INR >3.0, or platelets <20k
DVT (confirmed by imaging)	The presence of thrombosis of the iliac, femoral, or popliteal or other veins confirmed by imaging studies (duplex scan, CT, or MR) with or without swelling, warmth, erythema, or tenderness
OR hemorrhage >3,000 mL	Blood loss >3 L during the procedure.
Transfusion occurrence	The patient required an unplanned transfusion during or after the procedure, or adverse reaction to blood product transfusion
Other hematologic occurrence	Other hematologic adverse occurrence
Urologic complications
Foley catheter trauma	Injury to the urethra or bladder caused during normal insertion or removal of the Foley catheter, or during inadvertent removal of the catheter
Renal insufficiency (Cr >2 over base)	Operational definition: Failure of the kidneys characterized by rapid decline in glomerular filtration rate (hours to days), retention of nitrogenous waste products, and perturbation of extracellular fluid volume and electrolyte and acid–base homeostasis; criteria: Serum Cr >2 above baseline
Urinary retention	Inability to empty bladder under voluntary control
UTI	The presence of large amounts of bacteria (>100,000 organisms/mL) in the upper or lower urinary tract associated with symptoms or requiring treatment
Other urologic event	Other urologic adverse occurrence

ADH, antidiuretic hormone; ARDS, acute respiratory distress syndrome; CHF, congestive heart failure; CK-MB, creatinine kinase myocardial band; CPP, cerebral perfusion pressure; CPR, cardiopulmonary resuscitation; Cr, creatinine; CSF, cerebrospinal fluid; CBS, central nervous system; CT, computed tomography; CTA, computed tomographic angiography; CVA, cerebrovascular accident; CXR, chest x-ray; DBP, diastolic blood pressure; DVT, deep venous thrombosis; GI, gastrointestinal; Hct, hematocrit; ICP, intracranial pressure; INR, International Normalized Ratio; MAP, mean arterial pressure; MI, myocardial infarction; OR, operating room; ROMI, rule out myocardial infarction; SAH, subarachnoid hemorrhage; SBP, systolic blood pressure; TEE, transesophageal echocardiogram; TIA, transient ischemic attack; Tx, treatment; UTI, urinary tract infection.

Major complication.