About

The Modified Aldrete Score quantifies post-anesthesia recovery by evaluating five physiological parameters: Activity, Respiration, Circulation, Consciousness, and SpO₂. Each parameter scores 0, 1, or 2, producing a total between 0 and 10. A score ≥ 9 is the standard threshold for safe discharge from the Post-Anesthesia Care Unit (PACU). Misjudging recovery readiness risks respiratory depression, hemodynamic instability, or undetected hemorrhage. This tool implements the Modified Aldrete criteria as published by Aldrete (1995), replacing the original cyanosis criterion with pulse oximetry.

Limitations apply. The score does not assess pain, nausea, surgical-site bleeding, or cognitive orientation beyond simple arousal. Many institutions require supplementary criteria (e.g., Chung's PADSS for ambulatory surgery). Scoring intervals vary by protocol. Reassess at minimum every 15 minutes. Pro tip: document the time-stamped trajectory of scores, not just the final value. A patient who drops from 9 to 7 warrants investigation even if the latest score rebounds.

Formulas

The Modified Aldrete Score is a simple additive index:

A = 5∑i=1 C_i

where A = total Aldrete score, C_i = score for criterion i ∈ {0, 1, 2}, and the five criteria are Activity, Respiration, Circulation, Consciousness, and SpO₂.

Discharge rule:

{

DISCHARGE if A ≥ 9OBSERVE if A < 9

Range: 0 ≤ A ≤ 10. Each C_i is an ordinal scale reflecting progressive physiological competence. A score of 2 indicates baseline function. A score of 0 indicates absent or severely compromised function.

Reference Data

Criterion	Score 2	Score 1	Score 0
Activity	Moves all 4 extremities voluntarily or on command	Moves 2 extremities voluntarily or on command	Unable to move extremities
Respiration	Able to breathe deeply and cough freely	Dyspnea, shallow or limited breathing	Apneic
Circulation (BP)	± 20mmHg of pre-anesthetic level	± 20 - 49mmHg of pre-anesthetic level	± 50mmHg or more of pre-anesthetic level
Consciousness	Fully awake	Arousable on calling	Not responding
SpO₂	> 92% on room air	Needs O₂ inhalation to maintain SpO₂ > 90%	SpO₂ < 90% even with O₂ supplementation
Interpretation
Total Score	9 - 10: Ready for discharge \| 7 - 8: Continue monitoring \| ≤ 6: Requires close observation / intervention
Historical Context
Original Aldrete (1970)	Used skin color (cyanosis) instead of SpO₂. Less objective.
Modified Aldrete (1995)	Replaced color with pulse oximetry. Current standard.
Reassessment Interval	Every 5 - 15 min per institutional policy
PADSS (Chung)	Adds pain, nausea, bleeding, intake/output, ambulation for ambulatory surgery discharge
Typical PACU Stay	30 - 90 min for general anesthesia; 15 - 30 min for sedation
Minimum Score for D/C	≥ 9 (most institutions)
Maximum Possible Score	10
Number of Criteria	5

Frequently Asked Questions

Most institutions use a threshold of ≥ 9 out of 10. Some facilities accept 8 if the deducted point is attributable to a pre-existing condition (e.g., baseline limited mobility). Always follow your institutional protocol.

The original Aldrete Score (1970) assessed skin color (pink, pale, cyanotic) as the fifth criterion. The Modified version (Aldrete, 1995) replaced color assessment with pulse oximetry (SpO₂), providing an objective, quantifiable measurement. The scoring structure (0-2 per criterion, 5 criteria) remains identical.

Yes. The Aldrete Score does not evaluate pain intensity (VAS/NRS), postoperative nausea and vomiting (PONV), surgical-site bleeding, urinary retention, or ability to ambulate. A patient scoring 10 who is actively vomiting or has uncontrolled pain should not be discharged. Supplementary assessments like the PADSS (Post-Anesthesia Discharge Scoring System) address these gaps for ambulatory settings.

Standard practice is every 5 to 15 minutes. Many units assess at admission to PACU, then at 15-minute intervals. Patients showing declining scores or hemodynamic instability should be assessed more frequently. Document each assessment with a timestamp.

It applies but may be insufficient. For spinal or epidural anesthesia, motor and sensory block regression must be assessed separately (e.g., Bromage scale). For procedural sedation, the Aldrete Score can be used but recovery from sedation is typically faster, and discharge criteria may rely on the Ramsay Sedation Scale or institution-specific protocols.

Score against the patient's pre-operative baseline, not against a healthy standard. A patient who was wheelchair-bound pre-operatively and moves both upper extremities voluntarily post-operatively would score 1 for Activity (moves 2 extremities). Document the baseline limitation. Some institutions allow discharge at 8 in such cases with physician sign-off.

The original Modified Aldrete criterion references systolic blood pressure deviation from pre-anesthetic baseline. A deviation of ± 20mmHg scores 2, ± 20 - 49mmHg scores 1, and ≥ 50mmHg deviation scores 0. Some institutions have adopted MAP-based thresholds. Verify your facility's policy.