Infective Endocarditis Is a Risk Factor for Heparin Resistance in Adult Cardiovascular Surgical Procedures: A Retrospective Study.

OBJECTIVES: Heparin resistance (HR), defined as a decrease in heparin responsiveness, can result in adverse events with prolonged duration of surgery. Although some clinical risk factors have been suggested, the relationship with the surgical diagnosis is unclear. The aim of present study was to elucidate the clinical predictors of HR including the surgical diagnosis. DESIGN: This retrospective cohort study determined the incidence of HR (defined as activated clotting time [ACT] <400 seconds after 250-350 IU/kg of heparin administration) and heparin sensitivity index (HSI) was calculated from the rate of change in ACT per heparin dose. Preoperative demographic data, medication history, and laboratory data also were analyzed. SETTING: Single institution, tertiary care hospital. PARTICIPANTS: Adult patients who underwent cardiovascular surgery with cardiopulmonary bypass between January 2012 and September 2018. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 287 patients, 88 (30.7%) were classified as HR. In univariate analysis, infective endocarditis (IE), platelet count, and serum fibrinogen and albumin levels were associated with HR. After adjustment for baseline ACT and initial heparin dose, IE (odds ratio 4.57, [95% CI: 1.10-19.1]; p = 0.037) and albumin ≤3.5 g/dL (3.17, [1.46-6.93]; p = 0.004) were associated independently with HR. Patients with IE had significantly lower HSI than those with other diseases. All HR patients were treated with additional heparin, and 17 of them received human antithrombin-III concentrate. CONCLUSIONS: Infective endocarditis and preoperative hypoalbuminemia were associated independently with HR. The optimal anticoagulation strategy for patients with these risk factors requires further investigations based on the authors' findings.

Preoperative continuation of aspirin administration in patients undergoing major abdominal malignancy surgery.

PURPOSE: In contrast to that in a nonoperative setting, it has been shown that perioperative administration of aspirin did not decrease the rate of death or myocardial infarction but increased major bleeding risk. Since these conflicting results might be due to concurrent use of anticoagulants and a lower thrombotic risk of patients, this cohort study was carried out for patients at a high thrombotic risk without concurrent use of anticoagulants. METHODS: Medical records for patients who underwent major abdominal malignancy surgery and who were on a preoperative antiplatelet regimen were reviewed. The patients were divided into two groups according to perioperative antiplatelet management: administration of all preoperative antiplatelet agent-suspended (no aspirin) group and only aspirin administration-continued (aspirin) group. The incidence of symptomatic thromboembolic events, frequency of exogenous blood transfusion within 30 days after surgery and the amount of intraoperative bleeding were compared between the two groups. RESULTS: After propensity score matching, 105 patients of each group were matched. The incidence of perioperative thromboembolic events in the no-aspirin group was significantly higher than that in the aspirin group [7/105 (6.7%) vs 0/105 (0%), 95% CI 1.44-∞, P = 0.016]. In contrast, neither the frequency of exogenous transfusion [21.0% vs 11.4%, 95% CI 0.88-4.38 P = 0.110] nor the amount of intraoperative bleeding [median (interquartile range), ml: 230 (70-500) vs 208 (50-500), P = 0.325] was different between the two groups. CONCLUSION: Although the sample size is relatively small, our findings suggest that continuation of aspirin administration is likely to reduce the thrombotic risk but unlikely to increase the bleeding risk of patients who undergo major abdominal surgery for malignancy.

Current Ventilator and Oxygen Management during General Anesthesia: A Multicenter, Cross-sectional Observational Study.

BACKGROUND: Intraoperative oxygen management is poorly understood. It was hypothesized that potentially preventable hyperoxemia and substantial oxygen exposure would be common during general anesthesia. METHODS: A multicenter, cross-sectional study was conducted to describe current ventilator management, particularly oxygen management, during general anesthesia in Japan. All adult patients (16 yr old or older) who received general anesthesia over 5 consecutive days in 2015 at 43 participating hospitals were identified. Ventilator settings and vital signs were collected 1 h after the induction of general anesthesia. We determined the prevalence of potentially preventable hyperoxemia (oxygen saturation measured by pulse oximetry of more than 98%, despite fractional inspired oxygen tension of more than 0.21) and the risk factors for potentially substantial oxygen exposure (fractional inspired oxygen tension of more than 0.5, despite oxygen saturation measured by pulse oximetry of more than 92%). RESULTS: A total of 1,786 patients were found eligible, and 1,498 completed the study. Fractional inspired oxygen tension was between 0.31 and 0.6 in 1,385 patients (92%), whereas it was less than or equal to 0.3 in very few patients (1%). Most patients (83%) were exposed to potentially preventable hyperoxemia, and 32% had potentially substantial oxygen exposure. In multivariable analysis, old age, emergency surgery, and one-lung ventilation were independently associated with increased potentially substantial oxygen exposure, whereas use of volume control ventilation and high positive end-expiratory pressure levels were associated with decreased potentially substantial oxygen exposure. One-lung ventilation was particularly a strong risk factor for potentially substantial oxygen exposure (adjusted odds ratio, 13.35; 95% CI, 7.24 to 24.60). CONCLUSIONS: Potentially preventable hyperoxemia and substantial oxygen exposure are common during general anesthesia, especially during one-lung ventilation. Future research should explore the safety and feasibility of a more conservative approach for intraoperative oxygen therapy.

Effect of lung-protective ventilation-induced respiratory acidosis on the duration of neuromuscular blockade by rocuronium.

PURPOSE: The purpose of this study was to elucidate whether lung-protective ventilation-induced respiratory acidosis increased the duration of neuromuscular blockade by rocuronium. METHODS: A total of 72 patients were enrolled. After the induction of general anesthesia, rocuronium 0.6 mg/kg real body weight was administered. Tidal volume and positive end-expiratory pressure were randomly assigned as either 10 ml/kg predicted body weight and 0 cmH2O (group S) or 6 ml/kg and 5 cmH2O (group L), respectively. Respiratory rate was started at 10/min. Neuromuscular blockade was monitored by acceleromyography at the adductor pollicis with train-of-four stimulation. The time from the initial bolus injection of rocuronium to first recovery of the first twitch was defined as DUR1. Immediately, rocuronium 0.15 mg/kg was administered. The time from first recovery of the first twitch to second recovery of the first twitch was defined as DUR2. We also measured arterial pH (pH1 and pH2, respectively). RESULTS: Data from 66 patients (33 each in groups L and S) were eventually available. pH1 and pH2 were significantly lower in group L compared with group S [pH1: 7.308 (7.288-7.334) vs. 7.439 (7.423-7.466); p < 0.01, pH2: 7.306 (7.285-7.330) vs. 7.453 (7.436-7.476); p < 0.01]. DUR1 and DUR2 were significantly prolonged in group L compared with group S [DUR1: 31 (24-36) vs. 24 (20-30) min; p = 0.029, DUR2: 19 (15-22) vs. 15 (12-17) min; p = 0.020]. CONCLUSIONS: Lung-protective ventilation-induced respiratory acidosis increased the duration of neuromuscular blockade by rocuronium.

Effects of heparin bridging anticoagulation on perioperative bleeding and thromboembolic risks in patients undergoing abdominal malignancy surgery.

Recent publications provided controversial results indicating that perioperative heparin bridging anticoagulation (HBA) increased the bleeding risk without decreasing the thromboembolic risk in patients undergoing minor surgery. To investigate if this is also the case in high-risk patients undergoing major abdominal malignancy surgery, we retrospectively collected data of 3268 patients over a 10-year period. After the interruption of preoperative antithrombotic agents, HBA was initiated with a prophylactic-dose of unfractionated heparin in 133 patients (HBA group), and 62 patients did not receive HBA (non-HBA group). The incidence of exogenous blood transfusion (EBT) and thromboembolic events (TEEs) within 30 days after surgery were compared between the HBA and non-HBA groups. The results showed that the incidence of EBT and TEEs was similar between the two groups (23.3 vs 19.4 %; P = 0.535) and (4.1 vs 3.2 %; P = 0.821), respectively. The amount of intraoperative bleeding and the length of postoperative hospital stay were also similar [median (quantile 1-3); 192 (71-498) vs 228 ml (100-685); P = 0.422] and [12 (9-19) vs 14.5 days (10-21); P = 0.052], respectively. These findings may suggest it is unlikely that prophylactic-dose HBA affects bleeding and thromboembolic risks in patients undergoing major abdominal malignancy surgery.

[Thrombotic and Bleeding Risks of Patients on Antiplatelet Therapy Undergoing Major Abdominal Malignancy Surgery].

BACKGROUND: Controversies still exist whether to continue or withdraw aspirin (ASA) perioperatively. This study was performed to determine whether patients on preoperative antiplatelet therapy (APT) benefit from continuing ASA in terms of thrombotic and bleeding risk prevention. METHODS: Among 307 consecutive patients who were on APT preoperatively for the secondary prevention of cardiovascular disease and who underwent elective major abdominal malignancy surgery, 148 patients had all the preoperative APT withdrawn and the remaining 159 patients continued only ASA. Comparisons were made between the 2 groups regarding the rate and the amount of exogenous blood transfusion as well as the incidence of thromboembolic events (TEEs) within 1 month after surgery. RESULTS: The incidence of perioperative TEEs of the APT withdrawn group was significantly higher than that of the ASA group (6.2% vs 0%, P = 0.005), while the rate and the amount of exogenous blood transfusion were not different each other (23.6% vs 17.0%, P = 0.146 and 4 units vs 4 units, P = 0.544, respectively). CONCLUSIONS: Considering the relatively low bleeding risk when continued and the increased thrombotic risk after withdrawal, ASA should be continued perioperatively in patients undergoing major abdominal malignancy surgery.

Outcomes of Patients Who Undergo Transfusion of Fresh Frozen Plasma: A Prospective, Observational, Multicentre Cohort Study in Hiroshima, Japan.

PURPOSE: Given the chronic shortage of blood for transfusion in Japan, promotion of appropriate use of fresh frozen plasma (FFP) urgently needs to be addressed by the national blood project in Japan. Whether FFP transfusions are administered appropriately in Japan is currently unclear. In this study, we aimed to investigate the outcomes of patients who undergo FFP transfusion and the appropriateness of use of FFP. PATIENTS AND METHODS: This multicentre, prospective, observational cohort study was conducted from September 2017 to April 2019 at the 15 medical institutions in Hiroshima Prefecture that are the top providers of FFP. All patients who underwent FFP transfusion during the study period were included, relevant data being extracted from the medical records. The indications for FFP transfusion were classified in accordance with the Guidelines of the Ministry of Health, Labour and Welfare of Japan. Factors associated with patient outcomes at day 28 after FFP transfusion were subjected to multivariable logistic regression analysis. RESULTS: In total, data of 1299 patients were eligible for analysis. At least 63.8% of indications for FFP were in accordance with the guideline for FFP transfusions. The mortality rate at day 28 after FFP transfusion was 16.2%. Older age (65-74 years: adjusted odds ratio [AOR]=4.3, ≥75 years: AOR=4.1), non-perioperative use (AOR=4.5), coagulopathy associated with liver damage (AOR=2.7), large volume of FFP transfused (AOR=2.5), and lack of improvement in blood coagulation following FFP transfusion were independently and significantly associated with death within 28 days after FFP transfusion. CONCLUSION: Our findings do not support the simple conclusion that FFP transfusions contribute to prognosis. However, given that coagulopathy in patients with end-stage liver disease is infrequently improved by FFP transfusion, "inappropriate" use of FFP should be avoided. It is important to promote appropriate use of FFP so as not to waste blood resources.

[Combined use of paravertebral block and general anesthesia for breast cancer surgery].

BACKGROUND: Thoracic paravertebral block (TPVB) is reportedly a useful alternative of general anesthesia (GA) for patients undergoing major breast surgery. To provide surgical anesthesia by TPVB alone, however, demands considerable patient's discomfort during neural block and during surgery. This study was undertaken to investigate if TPVB adds to patient satisfaction when combined with GA for breast cancer surgery. METHODS: In 26 women (ASA I * II) undergoing modified radical mastectomy with axillary dissection, TPVB was performed at T 1 level and 15 ml of 0.5% ropivacaine was injected prior to induction of general anesthesia. After surgery, VAS (visual analogue scale, 0-100 mm) pain scores and postoperative medication were recorded. These data with TPVB were compared with those of 17 patients who had previously undergone similar surgical procedure without TPVB in our hospital. RESULTS: The VAS scores in patients with TPVB were 34 +/- 45 mm (mean +/- SD) on admission to the recovery room and 15 +/- 5 mm next morning. Frequency of postoperative administration of analgesics in patients with TPVB was significantly less than those without TPVB. CONCLUSIONS: Above findings suggest that combined use of TPVB and GA may be a preferable choice of anesthesia for patients undergoing major breast cancer surgery.

Effect of aspirin continuation on blood loss and postoperative morbidity in patients undergoing laparoscopic cholecystectomy or colorectal cancer resection.

No consensus exists whether to continue or withdraw aspirin therapy perioperatively in patients undergoing major laparoscopic abdominal surgery. To investigate whether preoperative continuation of aspirin therapy increases blood loss and associated morbidity during laparoscopic cholecystectomy and colorectal cancer resection, we compared duration of surgical procedures, amount of intraoperative blood loss, rate of blood transfusion, length of postoperative stay, rate of conversion to open surgery, and reoperation within 48 hours between patients with and without aspirin therapy preoperatively. Twenty-nine of 270 patients who underwent laparoscopic cholecystectomy and 23 of 218 patients who underwent laparoscopic colorectal cancer resection, respectively, were on aspirin therapy. We found no significant difference in the investigated outcome between groups with the exception of longer surgical duration of laparoscopic cholecystectomy in aspirin-treated patients. Although underpowered, above findings may suggest that aspirin continuation is unlikely to increase blood loss or postoperative morbidity in patients undergoing laparoscopic cholecystectomy or colorectal cancer resection.