Postoperative Respiratory Failure

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Estimate risk of postoperative respiratory failure.

Emergency case?
ASA Class
ASA 1 = Normal healthy patient
ASA 2 = Patients with mild systemic disease
ASA 3 = Patients with severe systemic disease
ASA 4 = Patients with severe systemic disease
that is a constant threat to life
ASA 5 = Moribund patients who are not expected
to survive without the operation
Preoperative Function
Preoperative sepsis: Defined as as the presence of SIRS along with positive blood culture, clinical documentation of purulence, or positive culture from any site thought to be causative.
Preoperative septic shock: Defined as SIRS or sepsis along with documented organ and/or circulatory dysfunction.
Preoperative systemic inflammatory response syndrome (SIRS): Defined by the presence of two or more of the following within 48 hours prior to surgery:

  • temperature >38 degrees celsius or
  • heart rate >90
  • respiratory rate >20 breaths/minute or PaCO2
  • white blood cell count>12,000 cell/mm3,10% immature (band) forms
  • Anion gap acidosis defined as [Na + K] – [CL + HCO3] > 16 or Na – [CL + HCO3] > 12.

About this calculator

This risk calculator provides a risk estimate of postoperative respiratory failure (PRF) for individual patients based on a model derived from a large sample of patients. This is intended to supplement the clinician’s own judgment and should not be taken as absolute.

Postoperative respiratory failure (PRF) is considered as failure to wean from mechanical ventilation within 48 hours of surgery or unplanned intubation/reintubation postoperatively.  The validated risk calculator provides a risk estimate of PRF and is anticipated to aid in surgical decision-making and informed patient consent.

The details of the methodology are provided in the published paper:


Gupta H, Gupta PK, Fang X, Miller WJ, Cemaj S, Forse RA, Morrow LE. Development and validation of a risk calculator predicting postoperative respiratory failure. Chest. 2011 Nov;140(5):1207-15. Epub 2011 Jul 14.