Impact of fentanyl on acute and chronic pain and its side effects when used with epidural analgesia after thoracic surgery in multimodal analgesia: a retrospective cohort study.

BACKGROUND: We investigated the effects adding opioids to epidural anesthesia on acute and chronic pain and its side effects in multimodal analgesia. METHODS: Retrospective cohort study. We retrospectively studied patients who received epidural anesthesia after thoracic surgery. Patients were divided into two groups: epidural anesthesia with fentanyl (group F) and without fentanyl (group N). Pain visual analog scale (VAS) scores at rest and after movement, use of non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen, side effects (nausea, vomiting, pruritus, hypotension, urinary retention), and post-thoracotomy pain syndrome (PTPS) were compared between the two groups. A Mann-Whitney U test and chi-squared test were used for statistical analysis, with significance set at P<0.05. Values were presented as median [interquartile range]. RESULTS: A total of 282 patients received epidural anesthesia, 142 in group F and 140 in group N. Resting pain and movement pain were lower in group F than those in group N {resting pain: group F 12 [0-29], group N 20.5 [7-38.5], P=0.01; movement pain, group F 43 [17-65]; group N, 51.5 [39-72]; P<0.001}. Incidence of hypotension was 9.9% in group F and 2.1% in group N (P=0.01), and that of pruritus was 41.5% in group F and 10.7% in group N (P<0.001). There is no difference in the incidence of nausea and vomiting and PTPS. CONCLUSIONS: In multimodal analgesia management after thoracic surgery, the addition of fentanyl to epidural anesthesia reduced acute pain and increased the incidence of hypotension and pruritus but did not affect that of PTPS.

Dispersion of Endoplasmic Reticulum-associated Compartments by 4-phenyl Butyric Acid in Yeast Cells.

In yeast Saccharomyces cerevisiae cells, some aberrant multimembrane-spanning proteins are not transported to the cell surface but form and are accumulated in endoplasmic reticulum (ER)-derived subcompartments, known as the ER-associated compartments (ERACs), which are observed as puncta under fluorescence microscopy. Here we show that a mutant of the cell surface protein Pma1, Pma1-2308, was accumulated in the ERACs, as well as the heterologously expressed mammalian cystic fibrosis transmembrane conductance regulator (CFTR), in yeast cells. Pma1-2308 and CFTR were located on the same ERACs. We also note that treatment of cells with 4-phenyl butyric acid (4-PBA) compromised the ERAC formation by Pma1-2308 and CFTR, suggesting that 4-PBA exerts a chaperone-like function in yeast cells. Intriguingly, unlike ER stress induced by the canonical ER stressor tunicamycin, ER stress that was induced by Pma1-2308 was aggravated by 4-PBA. We assume that this observation demonstrates a beneficial aspect of ERACs, and thus propose that the ERACs are formed through aggregation of aberrant transmembrane proteins and work as the accumulation sites of multiple ERAC-forming proteins for their sequestration.Key words: protein aggregation, organelle, unfolded protein response, ER stress, 4-PBA.