Port-Site Metastasis After Laparoscopic Gastrectomy Extending to the Thigh: A Case Report.

Port-site metastasis (PSM) is rare following laparoscopic gastrectomy for gastric cancer. Previous reports focused on localized lesions treated with excision; contrastingly, case reports describing extensive invasion into the lower extremity skeletal muscles causing deterioration in activities of daily living are nonexistent. A 55-year-old male underwent a laparoscopic distal gastrectomy for gastric cancer. The pathological findings revealed a stage IIIA tumor. Two years later, skin hardening was observed on the left upper abdominal wall. Computed tomography displayed a 13-cm-long, flat tumor along the skeletal muscle around the left upper 12 mm port site and right hydronephrosis. The patient was diagnosed with PSM and retroperitoneal recurrence. Despite chemotherapy, three years postoperatively, PSM widely spread from the left upper abdomen to the left thigh, eventually inducing opioid-resistant leg pain and subsequent walking difficulties. Palliative radiotherapy could not improve these symptoms. The patient died three years and five months postoperatively. Extensively invasive PSM can induce refractory cancer pain and physical disorders. Therefore, early detection and palliative resection of PSM may help maintain the quality of life of patients with gastric cancer.

Single-centre observational study of the safety and efficacy of thoracoscopy under local anaesthesia for the management of thoracic infections.

OBJECTIVES: Thoracoscopy under local anaesthesia is widely performed to diagnose malignancies and infectious diseases. However, few reports have described the use of this procedure for diagnosing and treating intrathoracic infections. This study aimed to evaluate the safety and efficacy of thoracoscopy under local anaesthesia for the management of intrathoracic infections. RESULTS: Data from patients who underwent thoracoscopy procedures performed by chest physicians under local anaesthesia at our hospital between January 2018 and December 2023 were retrospectively reviewed. We analysed their demographic factors, reasons for the examinations, diseases targeted, examination lengths, anaesthetic methods used, diagnostic and treatment success rates, as well as any adverse events. Thirty patients were included. Of these, 12 (40%) had thoracoscopies to diagnose infections, and 18 (60%) had them to treat pyothorax. In terms of diagnosing pleurisy, the causative microorganism of origin was identified via thoracoscopy in only three of 12 (25.0%) patients. For diagnosing pyothorax, the causative microorganism was identified in 7 of 18 (38.9%) patients. Methicillin-resistant Staphylococcus aureus was the most common causative microorganism identified. The treatment success rates were very high, ranging between 94.4 and 100%, whereas the identification rate of the causative microorganisms behind infections was low, ranging between 25.0 and 38.9%. The most frequent adverse events included perioperative hypoxaemia and pain. There were two (6.7%) serious adverse events of grade ≥ 3, but none resulted in death. CONCLUSIONS: The efficacy of managing intrathoracic infections through thoracoscopy under local anaesthesia is commendable. Nonetheless, the diagnostic accuracy of the procedure, regarding the precise identification of the causative microorganisms responsible for intrathoracic infections, persists at a notably low level, presenting a substantial clinical hurdle.

Clinical features of pneumothorax associated with COVID-19: A retrospective analysis of two centres.

BACKGROUND: Pneumothorax is a known sequela of coronavirus disease 2019 (COVID-19). However, the clinical features of pneumothorax associated with COVID-19 have not been fully elucidated. METHODS: Patients who developed pneumothorax within 6 months of being diagnosed with COVID-19 were retrospectively analysed at two institutions. We investigated the background factors, COVID-19 severity and treatment, timing of pneumothorax onset, treatment modalities, treatment duration, and prognosis of these patients. RESULTS: A total of 21 patients were diagnosed with pneumothorax within 6 months of COVID-19 diagnosis. The combined incidence rate of pneumothorax at two institutions was 0.89 %. The mean age of these patients was 72.5 years, and they were predominantly male (90.5 %), with a history of smoking (76.1 %). The most frequent comorbidity was hypertension, followed by type 2 diabetes mellitus, COPD, and malignancy. Approximately 76 % of the patients had moderate or severe disease requiring oxygenation. Moreover, 90.5 % of these patients were taking antiviral drugs; 52.4 %, immunosuppressant agents (baricitinib/tocilizumab); and 66.7 % were on dexamethasone. The median time to the onset of pneumothorax was 15.0 days, and 86 % of cases occurred within 1 month of COVID-19 diagnosis. Bilateral pneumothorax and pneumomediastinum were noted in one patient each. Chest drainage was performed in 71.4 % of the patients. The mean treatment duration for pneumothorax was 14.1 days, and the 30-day mortality rate was 28.6 %. CONCLUSION: Pneumothorax associated with COVID-19 was more common in patients with moderate or severe disease requiring oxygenation, and occurred within 1 month of COVID-19 diagnosis. Pneumothorax associated with COVID-19 is a serious complication with a high mortality rate and clinicians should pay attention to it.

Identification of complications requiring interventions after gastrointestinal cancer surgery from real-world data: An external validation study.

Background: Recently, real-world data have been recognized to have a significant role for research and quality improvement worldwide. The decision on the existence or nonexistence of postoperative complications is complex in clinical practice. This multicenter validation study aimed to evaluate the accuracy of identification of patients who underwent gastrointestinal (GI) cancer surgery and extraction of postoperative complications from Japanese administrative claims data. Methods: We compared data extracted from both the Diagnosis Procedure Combination (DPC) and chart review of patients who underwent GI cancer surgery from April 2016 to March 2019. Using data of 658 patients at Kyoto University Hospital, we developed algorithms for the extraction of patients and postoperative complications requiring interventions, which included an invasive procedure, reoperation, mechanical ventilation, hemodialysis, intensive care unit management, and in-hospital mortality. The accuracy of the algorithms was externally validated using the data of 1708 patients at two other hospitals. Results: In the overall validation set, 1694 of 1708 eligible patients were correctly extracted by DPC (sensitivity 0.992 and positive predictive value 0.992). All postoperative complications requiring interventions had a sensitivity of >0.798 and a specificity of almost 1.000. The overall sensitivity and specificity of Clavien-Dindo ≥grade IIIb complications was 1.000 and 0.995, respectively. Conclusion: Patients undergoing GI cancer surgery and postoperative complications requiring interventions can be accurately identified using the real-world data. This multicenter external validation study may contribute to future research on hospital quality improvement or to a large-scale comparison study among nationwide hospitals using real-world data.

Intraneural fibrosis within ilioinguinal nerve in inguinal hernia patients with preoperative pain: it's the sign of irreversible nerve injury, isn't it?

PURPOSE: Preoperative pain is known as one of the most powerful risk factors for chronic postoperative inguinal pain (CPIP), while its pathogenesis has not been fully elucidated. The aim of the present study was to evaluate patients with preoperative pain from the pathological perspective and discuss the potential pathogenesis of CPIP in those patients. METHODS: This was a single-institutional retrospective study. The study population was inguinal hernia patients with preoperative pain who underwent open anterior hernia repair for primary inguinal hernia with pragmatic ilioinguinal neurectomy during surgery between March 2021 and March 2023. The primary and secondary outcomes were proportion of collagen deposition and mucus accumulation within ilioinguinal nerve in those patients, respectively, which were evaluated histologically using Image J software. RESULTS: Forty patients were evaluated. Median value of proportion of intraneural collagen deposition was 38.3% (27.7-95.9). These values were positively correlated with the duration of pain (r2=0.468, P<0.001). Median value of proportion of mucus accumulation in ilioinguinal nerve was 50.1% (0-82.0). These values had no correlation with any clinicopathological variables. CONCLUSIONS: In the present study population, all patients with preoperative pain had intraneural fibrosis within ilioinguinal nerve, and its degree had a positive correlation with the pain duration.

A Case of Floating Aortic Arch Thrombosis in a Patient without Thrombophilia.

Floating aortic arch thrombi-blood clots forming in an aorta without aneurysms or atherosclerosis-in a normal aorta are exceedingly rare. The etiology is unknown, and there are no guidelines for appropriate treatment strategies. We report a case of floating aortic arch thrombosis in a patient without coagulopathy that was treated surgically. As the mass could not be identified preoperatively as a tumor or thrombus, synthetic graft replacement was performed, allowing resection of the lesion site. Histopathological examination revealed erosion and fissures in the tunica intima of the aorta, which suggested vessel damage to the tunica intima as the cause.

Impact of the COVID-19 pandemic on the trajectory of the number of bronchoscopies performed in a tertiary hospital in Kyoto city.

The coronavirus disease 2019 (COVID-19) pandemic has restricted many medical practices. We aimed to investigate the impact of the COVID-19 pandemic on the number of bronchoscopies, outpatients, and hospital admissions. We retrospectively analyzed the number of outpatients, admissions, and bronchoscopies performed between March 2020 and May 2022. We defined "Peak month of the pandemic," "Wave of the pandemic," "Month in the wave," and "Period of a state of emergency" for each analysis. In the first year of the COVID-19 pandemic, analysis of variance (ANOVA) in linear mixed models indicated significant effects of "month in each wave" on the number of bronchoscopies (P = .003), outpatients (P = .041), and admissions (P = .017). The number of outpatients, admissions, and bronchoscopies was significantly influenced by the first wave of the COVID-19 pandemic. In contrast, in the second year of the COVID-19 pandemic, a mixed-ANOVA indicated significant effects of "month in each wave" only on the number of outpatients (P = .020) but no significant effects on the number of bronchoscopies (P = .407) and admissions (P = .219). During the second year of the pandemic, the number of bronchoscopies and admissions was not significantly affected by the waves of the pandemic. There were no significant differences in the number of admissions and bronchoscopies between the fourth and sixth waves. Although the number of bronchoscopies was found to be significantly affected in the early stages of the COVID-19 pandemic, the impact of the pandemic was much more limited thereafter.

Comparison of the acceptability and safety of molnupiravir in COVID-19 patients aged over and under 80 years.

Background: Molnupiravir is being widely used as a treatment for coronavirus disease 2019 (COVID-19); however, its acceptability and safety in older patients aged ≥ 80 years in real-world clinical practice is not well understood. Methods: We conducted a single-centre retrospective study and assessed the outcome of patients with COVID-19 treated with molnupiravir according to the following criteria: (A) discontinuation rate of molnupiravir; (B) type, frequency, and severity of adverse events; (C) all-cause mortality within 30 days of the diagnosis of COVID-19. Results: Forty-seven patients (46.1%) were aged ≥ 80 years (older patients) and 55 (53.9%) were aged < 80 years (younger patients). There were no significant differences in coexisting diseases and history of vaccination for COVID-19 between older and younger patients. Older patients were significantly more likely to have moderate disease (moderate 1 and 2) according to the Japanese Ministry of Health, Labour and Welfare classification than younger patients. During treatment, 8.5% of older patients and 1.8% of younger patients stopped taking molnupiravir, but the difference was not significant. Adverse events were observed in 39/102 (38.2%) patients. The most common adverse events were diarrhoea (9.8%), exacerbation of coexisting diseases (6.9%), bone marrow suppression (6.9%), liver dysfunction (5.9%), and loss of appetite (4.9%). Most adverse events were minor, ranging from grades 1 to 3. The all-cause mortality rate was 10.8%, and no molnupiravir-related deaths were observed. Conclusions: Molnupiravir treatment is acceptable and safe in older patients with COVID-19 aged ≥ 80 years.

Comparison of Minimally Invasive Surgery with Open Surgery for Remnant Gastric Cancer: A Multi-institutional Cohort Study.

BACKGROUND: Despite growing evidence of the effectiveness of minimally invasive surgery (MIS) for primary gastric cancer, MIS for remnant gastric cancer (RGC) remains controversial due to the rarity of the disease. This study aimed to evaluate the surgical and oncological outcomes of MIS for radical resection of RGC. PATIENTS AND METHODS: Patients with RGC who underwent surgery between 2005 and 2020 at 17 institutions were included, and a propensity score matching analysis was performed to compare the short- and long-term outcomes of MIS with open surgery. RESULTS: A total of 327 patients were included in this study and 186 patients were analyzed after matching. The risk ratios for overall and severe complications were 0.76 [95% confidence interval (CI): 0.45, 1.27] and 0.65 (95% CI: 0.32, 1.29), respectively. The MIS group had significantly less blood loss [mean difference (MD), -409 mL; 95% CI: -538, -281] and a shorter hospital stay (MD, -6.5 days; 95% CI: -13.1, 0.1) than the open surgery group. The median follow-up duration of this cohort was 4.6 years, and the 3-year overall survival were 77.9% and 76.2% in the MIS and open surgery groups, respectively [hazard ratio (HR), 0.78; 95% CI: 0.45, 1.36]. The 3-year relapse-free survival were 71.9% and 62.2% in the MIS and open surgery groups, respectively (HR, 0.71; 95% CI: 0.44, 1.16). CONCLUSIONS: MIS for RGC showed favorable short- and long-term outcomes compared to open surgery. MIS is a promising option for radical surgery for RGC.

Antibiotic prophylaxis for percutaneous renal biopsy: study protocol for a prospective randomized trial.

BACKGROUND: The major complication of renal biopsy is bleeding. Infection is an extremely rare complication of percutaneous renal biopsy, providing sterile techniques are used and bowel perforation does not occur. However, the questionnaire included in the Kidney Biopsy Guidebook 2020 in Japan reported that antibiotic prophylaxis was administered to patients undergoing percutaneous renal biopsy at 61% of 170 adult institutions and 57% of 54 pediatric institutions. The objective of this study is to show the non-inferiority of not administering antibiotic prophylaxis for percutaneous renal biopsy. METHODS: Patients aged ≥15 years who are scheduled to undergo percutaneous renal biopsy are eligible for inclusion in the study. Three hundred and sixty-four patients will be recruited at 6 hospitals. The patients will be randomly assigned at a 1:1 ratio to receive either a single dose of intravenous cefazolin (1 g) or no antibiotic prophylaxis. The primary outcome is the number of patients that exhibit positive urine cultures (>105 colony-forming units/ml) 3 or 4 days after the renal biopsy, or at which point the patients are diagnosed with pyelonephritis until 3 or 4 days after the renal biopsy. The secondary outcomes are the number of patients who are diagnosed with pyelonephritis within 30 days after the renal biopsy, the number of patients who are diagnosed with puncture site infections within 30 days after the renal biopsy, the number of patients who are diagnosed with an infection other than pyelonephritis or a puncture site infection within 30 days after the renal biopsy, and the number of patients who experience cefazolin-induced side effects. DISCUSSION: This randomized controlled trial aims to show the non-inferiority of not administering antibiotic prophylaxis for percutaneous renal biopsy. If this study shows that antibiotic prophylaxis is not needed, it would help to ensure patient safety and prevent the development of antibiotic-resistant bacteria. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000042378 . Registered on 7 Nov 2020.

Safety assessment of robotic gastrectomy and analysis of surgical learning process: a multicenter cohort study.

BACKGROUND: The safety of robotic gastrectomy (RG) for gastric cancer in daily clinical settings and the process by which surgeons are introduced and taught RG remain unclear. This study aimed to evaluate the safety of RG in daily clinical practice and assess the learning process in surgeons introduced to RG. METHODS: Patients who underwent RG for gastric cancer at Kyoto University and 12 affiliated hospitals across Japan from January 2017 to October 2019 were included. Any morbidity with a Clavien-Dindo classification grade of II or higher was evaluated. Moreover, the influence of the surgeon's accumulated RG experience on surgical outcomes and surgeon-reported postoperative fatigue were assessed. RESULTS: A total of 336 patients were included in this study. No conversion to open or laparoscopic surgery and no in-hospital mortality were observed. Overall, 50 (14.9%) patients developed morbidity. During the study period, 14 surgeons were introduced to robotic procedures. The initial five cases had surprisingly lower incidence of morbidity compared to the following cases (odds ratio 0.29), although their operative time was longer (+ 74.2 min) and surgeon's fatigue scores were higher (+ 18.4 out of 100 in visual analog scale). CONCLUSIONS: RG was safely performed in actual clinical settings. Although the initial case series had longer operative time and promoted greater levels of surgeon fatigue compared to subsequent cases, our results suggested that RG had been introduced safely.

Mesenteric closure after laparoscopic total gastrectomy with Roux-en-Y reconstruction is effective for prevention of internal hernia: a multicenter retrospective study.

BACKGROUND: Internal hernia (IH) is one of the critical complications after gastrectomy with Roux-en-Y reconstruction, which can be prevented by closing mesenteric defects. However, only few studies have investigated the incidence of IH after laparoscopic total gastrectomy (LTG) with Roux-en-Y reconstruction for gastric cancer till date. This study aimed to assess the efficacy of defect closure for the prevention of IH after LTG. METHODS: This multicenter, retrospective cohort study collected data from 714 gastric cancer patients who underwent LTG with Rou-en-Y reconstruction between 2010 and 2016 in 13 hospitals. We evaluated the incidence of postoperative IH by comparing closure and non-closure groups of Petersen's defect, jejunojejunostomy mesenteric defect, and transverse mesenteric defect. RESULTS: The closure group for Petersen's defect included 609 cases, while the non-closure group included 105 cases. The incidence of postoperative IH in the closure group for Petersen's defect was significantly lower than it was in the non-closure group (0.5% vs. 4.8%, p < 0.001). The closure group for jejunojejunostomy mesenteric defect included 641 cases, while the non-closure group included 73 cases. The incidence of postoperative IH in the closure group of jejunojejunostomy mesenteric defect was significantly lower than that in the non-closure group (0.8% vs. 4.1%, p = 0.004). Out of 714 patients, 41 underwent retro-colic reconstruction. No patients in the transverse mesenteric defect group developed IH. CONCLUSION: Mesenteric defect closure after LTG with Roux-en-Y reconstruction may reduce postoperative IH incidence. Endoscopic surgeons should take great care to prevent IH by closing mesenteric defects.

Increasing Burden of Nursing Care on the Treatment of COVID-19 Patients in the Aging Society: Analyses During the First to the Third Wave of Pandemic in Kyoto City, Japan.

Background: The coronavirus disease 2019 (COVID-19) pandemic is associated with a heavy burden on patient's mental and physical health, regional healthcare resources, and global economic activity. An aging society such as Japan has many retirement homes and long-term stay hospitals for the elderly and their inhabitants. During the COVID-19 pandemic, disease clusters are often identified in retirement homes and long-term stay hospitals. Although we hypothesize that additional burdens of nursing care for elderly patients will reinforce the anxiety and exhaustion of medical staff and healthcare resources in the aging society, the actual situation is not well understood. In this study, we aimed to evaluate the current situation and countermeasures of the COVID-19 pandemic in the aging society. Methods: We reviewed COVID-19 patients who required hospitalization at the National Hospital Organization Kyoto Medical Center, a 600-bed capacity hospital located in Kyoto, Japan, between 1 April 2020 and 31 March 2021. We assessed the characteristics of the COVID-19 patients, disease severity, duration of hospitalization, outcome at discharge, degree of activities of daily living (ADLs), and complications unique to elderly patients. Results: We enrolled 118 patients who required hospitalization during the study period. Approximately 40% of the patients were aged ≥ 80 years. Dementia (27.1%) was the most prevalent underlying disease, followed by diabetes mellitus (23.7%) and chronic kidney disease (23.7%). Approximately 60% of hospitalized COVID-19 patients had impaired ADL at admission. The COVID-19 patients aged 80 years or older required significantly more longer-term hospitalization than the COVID-19 patients aged under 80 years (15.5 ± 8.2 vs. 13.1 ± 7.7, P = 0.032). In elderly patients aged 80 years or older, approximately 50% of patients had geriatric mental disorders, and approximately 70% had bedridden status and feeding difficulty. Poor ADL at admission was significantly associated with COVID-19 mortality (Odds ratio, 5.6; 95% confidence interval, 1.04-45.2; p-value = 0.044). Conclusions: The proportion of elderly patients aged 80 years or older was relatively high during the hospitalization for COVID-19. Poor ADL at admission in these elderly patients was significantly associated with poor prognosis of COVID-19. We should keep in mind that healthcare workers are forced to have an additional burden of nursing care in the aging society during the COVID-19 pandemic. Therefore, interventions to reduce the burden are urgently required.

Safety of Remdesivir for Patients 80 Years of Age or Older with Coronavirus Disease 2019 (COVID-19).

BACKGROUND AND OBJECTIVE: Although older patients with coronavirus disease 2019 (COVID-19) are at the high risk of exacerbation that requires treatment with remdesivir, the safety of this medication is unclear in clinical practice, especially among older patients. We aimed to retrospectively evaluate the safety of remdesivir in older patients with COVID-19 who required hospitalization in our institute. METHODS: We reviewed patients with COVID-19 who were treated with remdesivir at our institute between July 2020 and May 2021. We defined older patients as those aged 80 years or older at admission; all other patients were defined as younger patients. We evaluated the safety of remdesivir by examining the incidence of discontinuation of remdesivir treatment because of adverse events and the incidence of any adverse events. RESULTS: A total of 80 patients were included in this study. Compared with younger patients, fewer older patients were treated with remdesivir for more than 5 days: 4 (15.4%) vs 23 (42.6%). Discontinuation of remdesivir because of adverse events occurred in one older patient (3.9%) and four younger patients (7.4%) [p > 0.99]. Remdesivir-induced liver dysfunction was the most frequent adverse event, which occurred in 29 (36.3%) patients. There were no significant differences in the incidence of remdesivir-induced liver dysfunction, renal dysfunction, and fatigue. CONCLUSIONS: The safety of remdesivir was suggested to be comparable between patients older than 80 years of age and patients younger than 80 years of age. The results of this study may encourage the administration of remdesivir to this older patient group.

Acute rhabdomyolysis in a young woman with moderate COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having serious medical, social, and economic impacts worldwide. COVID-19 may lead to a variety of complications, including rhabdomyolysis. Although rhabdomyolysis is a rare complication, it can lead to severe kidney damage. Recent studies suggest that rhabdomyolysis caused by SARS-CoV-2 is more common in middle-aged and older men with severe COVID-19. Herein we report a case of rhabdomyolysis in a young woman with moderate COVID-19. She had a habit of muscle training. She presented with moderate COVID-19 and acute rhabdomyolysis that required a large volume of fluid infusion in addition to dexamethasone and remdesivir. Clinicians should pay attention to the development of rhabdomyolysis in patients with COVID-19, especially those with a habit of strenuous exercise or muscle training, even if they are young and have moderate COVID-19.

Change in antimicrobial susceptibility of pathogens isolated from surgical site infections over the past decade in Japanese nation-wide surveillance study.

Inappropriate antimicrobial therapy for surgical site infections (SSIs) can lead to poor outcomes and an increased risk of antibiotic resistance. A nationwide survey was conducted in Japan from 2018 to 2019 to investigate the antimicrobial susceptibility of pathogens isolated from SSIs. The data were compared with those obtained in 2010 and 2014-2015 surveillance studies. Although the rate of detection of extended-spectrum ß-lactamase producing strains of Escherichia coli was increased from 9.5% in 2010 to 23% in 2014-2015, the incidence decreased to 8.7% in 2018-2019. Although high susceptibility rates were detected to piperacillin/tazobactam (TAZ), the geometric mean MICs were substantially higher than to meropenem (2.67 vs 0.08 µg/mL). By contrast, relatively low geometric mean MICs (0.397 µg/mL) were demonstrated for ceftolozane/TAZ. Although the MRSA incidence rate decreased from 72% in the first surveillance to 53% in the second, no further decrease was detected in 2018-2019. For the Bacteroides fragilis group species, low levels of susceptibility were observed for moxifloxacin (65.3%), cefoxitin (65.3%), and clindamycin (CLDM) (38.9%). In particular, low susceptibility against cefoxitin was demonstrated in non-fragilis Bacteroides, especially B. thetaiotaomicron. By contrast, low susceptibility rates against CLDM were demonstrated in both B. fragilis and non-fragilis Bacteroides species, and a steady decrease in susceptibility throughout was observed (59.3% in 2010, 46.9% in 2014-2015, and 38.9% in 2018-2019). In conclusion, Japanese surveillance data revealed no significant lowering of antibiotic susceptibility over the past decade in organisms commonly associated from SSIs, with the exception of the B. fragilis group.

Cerebral oxygen saturation (rSO2) during cardiopulmonary bypass (CPB) measured using the INVOS oximeter closely correlates with baseline rSO2.

Baseline cerebral regional saturation (rSO2) measured using the INVOS 5100C (Medtronic, MN, USA) varies widely among patients with cardiac and/or renal diseases. To identify significant correlates of baseline rSO2 and to investigate intraoperative rSO2 changes, we conducted a retrospective study in 494 patients undergoing on-pump cardiovascular surgery. Correlations between preoperative blood laboratory test variables and baseline rSO2 before anesthesia were examined. Intraoperative rSO2 changes were analyzed. Of all the variables examined, log-transformed B-type natriuretic peptide (BNP) most significantly and negatively correlated with baseline rSO2 (r = - 0.652, p < 0.0001). Intraoperatively, rSO2 showed the lowest value during cardiopulmonary bypass (CPB) (median rSO2: 56.2% during CPB vs. 63.9% at baseline, p < 0.0001). Although rSO2 during CPB correlated positively with hemoglobin concentration and oxygen delivery during CPB (r = 0.192, p < 0.0001; and r = 0.172, p = 0.0001, respectively), it correlated much more closely with baseline rSO2 (r = - 0.589, p < 0.0001). Thus, patients showing low baseline rSO2 primarily associated with preoperatively high BNP continued to show low rSO2 even during CPB independent of hemodynamics artificially controlled by CPB. Our findings suggest that low baseline rSO2 in patients with high BNP due to cardiac and/or renal diseases is more likely to result from tissue edema causing alterations in optical pathlength and thus in calculated rSO2 values, not readily modifiable with CPB, rather than actual cerebral hemodynamic alterations readily modifiable with CPB. These may partly explain why the INVOS oximeter is a trend monitor requiring baseline measures.