深野 賢太朗

BACKGROUND: Intercostal nerve block (ICNB) plus intravenous (IV) patient-controlled analgesia (PCA) could be an alternative method of perioperative pain management in patients undergoing video-assisted thoracic surgery (VATS). However, the efficacy of this strategy has not been established. METHODS: A retrospective observational study was conducted at an acute care hospital in Japan. Among patients who underwent VATS under general anesthesia from January 1, 2012, to December 31, 2022, we included those who received ICNB or thoracic epidural anesthesia (TEA). The ICNB group had postoperative IV PCA, and the TEA group had postoperative epidural PCA. VATS indicated for pneumothorax or biopsy was excluded. The primary outcome was the maximum pain score measured by the numerical rating scale on postoperative day 1. Secondary outcomes included the times rescue analgesics were used and the use of antiemetics. Propensity score matching was performed to minimize bias from nonrandomized assignment of anesthesia methods. RESULTS: Among 1,641 patients who met the criteria, 590 underwent ICNB and IV PCA, while 1,051 received TEA. After 1:1 propensity score-matching, 456 were in each group. The median (interquartile range) pain score on postoperative day 1 was higher in the ICNB group than in the TEA group, with values of 5 (4-7) vs. 3 (2-5) (p < 0.0001). Patients in the ICNB group more frequently used rescue analgesics on postoperative day 0, with values of 2 (1-2) vs. 1 (1-2) (p < 0.0001), and had a higher proportion of receiving antiemetics on postoperative day 1 (13.4% vs. 6.1%, p = 0.0004), compared to the patients in the TEA group. CONCLUSIONS: ICNB plus IV PCA was inferior to TEA for postoperative pain management of VATS in the study population. Protocol-based prospective studies are needed to determine the efficacy of this strategy.

BACKGROUND: Ascorbic acid is a strong antioxidant that prevents postoperative delirium by inhibiting reactive oxygen species production. This pilot study was designed to investigate the prevalence of postoperative delirium among older patients undergoing cardiovascular surgery, who received perioperative ascorbic acid administration, to estimate an appropriate sample size for further randomized controlled trials. METHODS: This single-arm prospective interventional study enrolled patients aged > 70 years scheduled to undergo elective cardiovascular surgery using cardiopulmonary bypass. Ascorbic acid (500 mg) was administered intravenously every 6 h for a total of eight times following the induction of general anesthesia. The incidence of postoperative delirium was evaluated until discharge using the Confusion Assessment Method for the Intensive Care Unit. RESULTS: Data from 48 patients were analyzed. Of the 48 patients, 16 developed postoperative delirium (33.3%). Patients in the delirium group had more severe heart failure (New York Heart Association Classification), higher European System for Cardiac Operative Risk Evaluation scores, lower intraoperative Bispectral Index, longer duration of cardiopulmonary bypass and surgery, incidence of postoperative cerebral infarction, longer intubation time, and length of intensive care unit stay. CONCLUSIONS: The incidence of postoperative delirium among older patients undergoing cardiovascular surgery who received ascorbic acid perioperatively (2 g/day for 2 days) was 33%. This incidence was comparable to that observed in a previous observational study, suggesting that ascorbic acid administration may not be effective in preventing the incidence of postoperative delirium.