Evaluation of acute pain: "objective pain score" Vs. "numeric rating scale"
For acute pain management, the pain scores are used variably. Various factors are used for the assessment of pain by the patient as well as the caregiver. The most common scale used for this purpose is the numeric rating scale (NRS). The application of this scale is the abstract thinking by a patient to assign a score to correctly reflect analgesic needs and its analysis is subject to bias. This study was performed to evaluate the acute postoperative pain and its comparison with the NRS to endorse a 4-point objective pain score (OPS).
About 93 patients who underwent laparotomy and used patient-controlled analgesia were taken up. They showed 1021 paired readings of the OPS and NRS which were tracked by Acute pain service (APS) personnel. Two incremental levels were formed from the rescue analgesia - level 1-paracetamol 1 g for NRS 2 - 5 and OPS 3, Level 2-Fentanyl 25 mcg for NRS ≥ 6 and OPS 1 and 2. An individualistic consultant decided rescue analgesia when there were incidents of disagreement between the two scores.
There was a total agreement between NRS and OPS across the pain range with 25 disagreements in 8 patients. The rescue analgesia was raised from level 1 to 2 on 24 occasions but it lowered from level 2 to 1 in one occasion. The verdict to supplement analgesia went towards OPS over the NRS on all 25 occasions. There were 17 occasions in which observer bias was possible for level 2 rescue analgesia apart from the 25 disagreements.
The OPS outshined the NRS as a stand-alone pain score for defining mild and moderate pain.