Intraoperative Lung Protective Ventilation Needs Periodic Lung Recruitment Maneuvers

Respiratory failure: postoperative arterial partial pressure of oxygen (PaO2) < 8 kPa (60 mmHg) on room air, a PaO2: Inhaled oxygen concentration (FI02) ratio < 40 kPa (300 mmHg) or arterial oxyhaemoglobin saturation measured with pulse oximetry < 90% and requiring oxygen therapy

Mild respiratory failure: PaO2 < 60 mmHg or pulse oxygen saturation (SpO2) < 90% on room air, but SpO2 can be raised to more than 90% when inhaling oxygen through nasal catheter less than 3 L/min.

Moderate respiratory failure: PaO2 < 60 mmHg or SpO2 < 90% when inhaling oxygen through nasal catheter less than 3 L/min, but SpO2 can be raised to more than 90% when inhaling oxygen more than 3 L/min.

Severe respiratory failure: experienced an invasive or noninvasive ventilator therapy, or PaO2 < 60 mmHg or SpO2 < 90% when administering oxygen via a nasal catheter at 3 L/min or more.

Sustained hypoxaemia: during a follow-up visit when the patient was awake and breathing room air, SpO2 ≤ 92% or the change of SpO2 (ΔSpO2, preoperative SpO2 minus postoperative SpO2) ≥ 5% on any three consecutive days.

Modified respiratory failure: met the criterion of moderate or severe respiratory failure, or mild respiratory failure in twice follow-up, or mild respiratory failure with sustained hypoxemia.

Respiratory infections: receiving antibiotics for a suspected respiratory infection and met at least one of the following criteria: new or changed sputum, new or changed lung opacities, fever, leukocyte count >12 × 109 /L

Pneumonia: United States Centers for Disease Control definition of pneumonia

Aspiration pneumonitis: acute lung injury after the inhalation of regurgitated gastric contents.

Pneumothorax: air in the pleural space with no vascular bed surrounding the visceral pleura

Pleural effusion: chest radiograph demonstrating blunting of the costophrenic angle, loss of sharp silhouette of the ipsilateral hemidiaphragm in upright position, evidence of displacement of adjacent anatomical structures or (in supine position) a hazy opacity in one hemithorax with preserved vascular shadows

Acute Respiratory Distress Syndrome: The Berlin definition of Respiratory Distress Syndrome

qSOFA ≥ 2: Two or more of: Respiratory rate ≥22/min, Altered mentation, Systolic blood pressure ≤ 100 mm Hg

SIRS: Two or more of: Temperature >38°C or <36°C, Heart rate > 90/min, Respiratory rate >20/min or PaCO2<32 mmHg (4.3kPa), White blood cell count >12 000/mm3 or 10% immature bands

MACCE: Stroke, coma, non-fatal cardiac arrest, acute myocardial infarction, congestive heart failure.

The duration between the operation date and the actual discharge date, days

Unexpected admission to ICU: It does not include patients who enter ICU at the request of surgeons but have normal spontaneous breathing, stable circulation and no disturbance of consciousness.

Death from any cause

Intraoperative hypotension: mean arterial pressure (MAP) < 60 mmHg lasting more than 3 minutes

Intraoperative vasoconstrictor needs: MAP < 60 mmHg and using any catecholamines

Intraoperative hypoxemia: SpO2 ≤ 92% lasting more than 3 minutes

Intraoperative bradycardia: heart rate ≤ 50 bpm and the decrease of heart rate from the basic value ≥ 20% lasting more than 3 minutes

Post-anesthesia care unit respiratory failure: PaO2 < 8 kPa (60 mmHg) on room air, a PaO2:FI02 ratio < 40 kPa (300 mmHg) or arterial oxyhaemoglobin saturation measured with pulse oximetry < 90% and requiring oxygen therapy

Mechanical power, J/min

PaO2 / FI02, mmHg

Postoperative pulmonary complications score: graded on a scale from 0 (no pulmonary complications) to 4 (the most severe complications).

Dead space rate (%)