Arozullah Respiratory Failure Index

Predicts postoperative risk of PRF in elderly male patients based on available clinical data and type of surgery.

Refer to the text below the calculator for more information about the original study and the variables used in the model.


Postoperative respiratory failure (PRF), defined as risk of mechanical ventilation for >48 hrs after surgery, or unplanned intubation ≤30 days of surgery, is among the most serious of the postoperative pulmonary complications.

The study by Arozullah et al. determined six preoperative predictors of PRF in a large multicenter observational cohort of 81,719 subjects from 44 Veterans Affairs Medical Centers undergoing major noncardiac surgery.


Points Class Predicted Probability of Postoperative Respiratory Failure
≤10 1 0.5%
11 - 19 2 2.2%
20 - 27 3 5.0%
28 - 40 4 11.6%
>40 5 30.5%

1

Type of surgery

2

Albumin (<30 g/L)

3

Blood urea nitrogen (>30 mg/dL)

4

Partially or fully dependent functional status

5

History of chronic obstructive pulmonary disease

6

Age

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Arozullah Respiratory Failure Index Explained

Postoperative respiratory failure (PRF), defined as risk of mechanical ventilation for >48 hrs after surgery, or unplanned intubation ≤30 days of surgery, is among the most serious of the postoperative pulmonary complications.

The study by Arozullah et al. determined six preoperative predictors of PRF in a large multicenter observational cohort of subjects undergoing major noncardiac surgery.

The development cohort consisted of 81,719 patients from 44 Veterans Affairs Medical Centers whilst the validation cohort consisted of 99,390 patients from 132 Veterans Affairs Medical Centers. The study excluded ventilator-dependent, comatose, do not resuscitate, and female patients.

Postoperative respiratory failure developed in 3.4% of patients. The RFI was developed from a simplified logistic regression model. The risk predictors that are used include:

Preoperative PRF risk factor Answer choices Pts
Type of surgery Abdominal aortic aneurysm 27
Thoracic 21
Neurosurgery, upper abdominal, or peripheral vascular 14
Neck 11
Emergency surgery 11
Albumin (<30 g/L) Yes 9
No 0
Blood urea nitrogen (>30 mg/dL) Yes 8
No 0
Partially or fully dependent functional status Yes 7
No 0
History of chronic obstructive pulmonary disease Yes 6
No 0
Age (Years) ≥70 7
60-69 4

The table below summarizes the final score interpretation and associated risk of PRF:

Points Class Predicted Probability of Postoperative Respiratory Failure
≤10 1 0.5%
11 - 19 2 2.2%
20 - 27 3 5.0%
28 - 40 4 11.6%
>40 5 30.5%
 

Reference

Arozullah AM, Daley J, Henderson WG, Khuri SF. Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. The National Veterans Administration Surgical Quality Improvement Program. Ann Surg. 2000; 232(2):242-53.


Specialty: Surgery

Year Of Study: 2000

Article By: Denise Nedea

Published On: November 2, 2020

Last Checked: November 2, 2020

Next Review: November 2, 2025