Higher actual postoperative pain scores and unacceptable pain, even on the first postoperative day, are associated with more postoperative complications. Our findings provide important support for the centrality of personalized analgesia in modern perioperative care.

BackgroundClinical experience teaches us that patients are willing to accept postoperative pain, despite high pain intensity scores. Nevertheless, relationships between pain scores and other methods of pain assessment, e.g. acceptability of pain or its interference with physical functioning, are not fully established. Our aims were to examine these relationships.MethodsA cross-sectional study was conducted on patients who underwent major surgery between January 2008 and August 2013. Using logistic regression, we quantified the relationships between movement-evoked pain scores on the numerical rating scale (NRS-MEP) and three dichotomous dependent variables: patient’s opinion on acceptability of pain (PO: acceptable or unacceptable pain); nurses’ observation of patient’s performance of necessary activities to expedite recovery (NO: good or bad performance); a compound measure judging the presence of the clinically desirable situation of acceptable pain associated with good patients’ performance (PONO: present or not). Using Receiver Operating Characteristics (ROC) analysis, NRS cut-off points were determined such that they best discriminate between patients having one versus the other outcome for PO, NO and PONO.Results15,394 assessments were obtained in 9,082 patients in the first three postoperative days. Nine percent of the patients had unacceptable pain while having an NRS-MEP of 0–4. An estimated 47% (95%CI = 45%-49%) of patients with an NRS-MEP of 7 described their pain as acceptable on day one. Moreover, 33% (31%-35%) performed all required physical activities, and 22% (21%-24%) combined acceptable pain with appropriate movement. NRS cut-off points for PO, NO and PONO were five, four and four, respectively, but had insufficient discriminatory power.ConclusionsOur results suggest pain management should be guided by the many dimensions of the patient’s pain experience, not solely by NRS cut-off points. Future research should evaluate the impact of such multidimensional pain assessment on patients’ functional outcome.

The blink reflex (brainstem function) is more sensitive to sevoflurane or propofol than BIS (forebrain function). Sevoflurane suppresses the blink reflex more than propofol. Different k(e0)s for blink reflex vs BIS indicate different effect sites.

Eight physiological variables--tidal volume, breathing rate, end-tidal carbon dioxide fraction, oxygen fraction in the anesthetic circuit, oxygen saturation by pulse oximetry, systolic and diastolic blood pressure, and heart rate--recorded on-line by a commercially available automated system were compared with the same variables recorded on handwritten anesthesia records. We quantified the differences between the automated and handwritten records generated from the same 30 patients (2,412 minutes of general anesthesia for elective eye surgical procedures). Considering the design of the study, we claim that the differences between both records were caused by the incompleteness or inaccuracy of the handwritten records, except in two instances. The amounts of missing or erroneous data for these eight physiological variables were expressed as fraction ("error fractions") of the time being recorded, designated EFm and EFe, respectively. For the first five variables the EFm on the handwritten records ranged between 0.23 and 0.31, and the EFe ranged between 0.01 and 0.06. For the last three variables the EFm range was 0.08 to 0.13, and the EFe range was 0.05 to 0.11. Most of these missing or erroneous data occurred during the period of induction (first 15 minutes) and at the end of the case (last 10 minutes). The EFm and EFe during induction had increased to 0.62 and 0.26, respectively, and to 0.76 and 0.06, respectively, at the end of the case. Erroneous data were observed on the automated records for the tidal volume during induction (EFe = 0.0044) and for the oxygen fraction during maintenance (EFe = 0.0024). The effect of averaging by the recordkeeper is discussed. The results of this study indicate the clinical relevance of automated record keeping.

The nomogram gives accurate results if it covers a whole A4 sheet in landscape format and could be extended to apply to other agents, for example xenon.