Objective Assessment of the Immediate Postoperative Analgesia Using Pupillary Reflex Measurement

Abstract

In the immediate postoperative period, the PDR is significantly correlated with the VRS. The pupillometer could be a valuable tool to guide morphine administration in the immediate postoperative period.

Pupillary reflex measurement predicts insufficient analgesia before endotracheal suctioning in critically ill patients

“…[9] confirm that PDR is an earlier and more sensitive response predictor of analgesia than the hemodynamic changes or the bispectral index (BIS) in children under general anesthesia. In the immediate postoperative period, the PDR is significantly correlated with the verbal rating scale [10]. The authors concluded that the PDR could be useful to assess pain in patients with whom direct communication is difficult.…”

Pupil diameter during postanesthetic recovery is not influenced by postoperative pain, but by the intraoperative opioid treatment

“…Two recent studies were conducted in a setting close to ours, after various surgeries performed during balanced general anesthesia. Aissou et al [13] observed 61 patients in whom a PDR was elicited by an intentional pressure applied to the wound and measured before and after morphine given for pain relief. Although neither spontaneous pain before morphine nor pain relief after morphine influenced the baseline PD before the additional noxious stimulation, both variables were well correlated to the intensity of PDR.…”

“…As in the 2 previous studies conducted in PACU, we intentionally included a heterogeneous population and had a liberal attitude toward the practice of anesthesia and analgesia, aiming to reflect routine clinical practice [13,14]. In such observational design, it is difficult to distinguish the effects of pain (and analgesia in general) and those of opioids administered postoperatively.…”

“…Feeling that such conditions were far from the clinical context, the immediate postoperative period was studied. Two similar observational studies failed to find a significant relation between early postoperative pain and PD [13,14].…”

Objective Assessment of Acute Pain

“…Both the pupil diameter response to the noxious stimulus itself and light induced dilatation are thought to reflect sympathetic responses to pain. However, there are inconsistent results regarding the correlation between pupillary responses and post-operative self-reported pain scores [33][34][35]. Responses can also be influenced by drugs including opioids and vasoactive agents, along with environmental luminance and genuine conditions of the eye [36].…”