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% |
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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 · 12:00 AM
Last Checked: November 2, 2020
Next Review: November 2, 2025