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.

Relationship between a High-inspired Oxygen Concentration and Dorsal Atelectasis in High-energy Trauma Patients.

We performed a retrospective cohort study of 911 high-energy trauma patients who underwent chest CT scans at least twice after admission. We hypothesized that in high-energy trauma patients, a high-inspired oxygen concentration delivered after admission results in dorsal atelectasis. The study's primary outcome was dorsal atelectasis formation diagnosed based on CT images. We defined dorsal atelectasis as the presence of atelectasis at ≥ 10 mm thick on CT images. We defined high-inspired oxygen concentration as >60% oxygen delivered between two CT scans. Four hundred sixty-five patients (51.0%) developed atelectasis according to the second CT scan, and 338 (37.1%) received a high-inspired oxygen concentration. A univariate analysis showed that the rate of the high-inspired oxygen concentration in the atelectasis group was significantly higher than that in the non-atelectasis group (43.4% vs. 30.1%, p<0.001). However, a logistic regression analysis showed that there was no significant relationship between the oxygen concentration and the formation of dorsal atelectasis (OR: 1.197, 95%CI: 0.852-1.683, p=0.30). Age, the Injury Severity Score, BMI, and smoking were found to be risk factors of dorsal atelectasis formation in high-energy trauma patients. There was no relationship between the oxygen concentration and atelectasis formation in our series of high-energy trauma patients.

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.

Safety and feasibility of liver resection with continued antiplatelet therapy using aspirin.

BACKGROUND: Aspirin is widely used for the secondary prevention of ischemic stroke and cardiovascular disease. Perioperative aspirin may decrease thrombotic morbidity, but may also increase hemorrhagic morbidity. In particular, liver resection carries risks of bleeding, leading to higher risks of hemorrhagic morbidity. Our institution has continued aspirin therapy perioperatively in patients undergoing liver resection. This study examined the safety and feasibility of liver resection while continuing aspirin. METHODS: We retrospectively evaluated 378 patients who underwent liver resection between January 2010 and January 2016. Patients were grouped according to preoperative aspirin prescription: patients with aspirin therapy (aspirin users, n = 31); and patients without use of aspirin (aspirin non-users, n = 347). RESULTS: Aspirin users were significantly older (P < 0.001), with a higher proportion of males (P < 0.001) and higher frequencies of hypertension (P = 0.004) and diabetes mellitus (P < 0.001). No significant differences were observed in intraoperative parameters. Although the frequency of major morbidity tended to be higher among aspirin users than among aspirin non-users, no significant difference was identified. No postoperative hemorrhage was seen among aspirin users. CONCLUSIONS: Liver resection can be safely performed while continuing aspirin therapy without increasing hemorrhagic morbidity. Our results suggest that interruption of aspirin therapy is unnecessary for patients undergoing liver resection.

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.

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.

Species identification of animal cells by nested PCR targeted to mitochondrial DNA.

We developed a highly sensitive and convenient method of nested polymerase chain reaction (PCR) targeted to mitochondrial deoxyribonucleic acid (DNA) to identify animal species quickly in cultured cells. Fourteen vertebrate species, including human, cynomolgus monkey, African green monkey, mouse, rat, Syrian hamster, Chinese hamster, guinea pig, rabbit, dog, cat, cow, pig, and chicken, could be distinguished from each other by nested PCR. The first PCR amplifies mitochondrial DNA fragments with a universal primer pair complementary to the conserved regions of 14 species, and the second PCR amplifies the DNA fragments with species-specific primer pairs from the first products. The species-specific primer pairs were designed to easily distinguish 14 species from each other under standard agarose gel electrophoresis. We further developed the multiplex PCR using a mixture of seven species-specific primer pairs for two groups of animals. One was comprised of human, mouse, rat, cat, pig, cow, and rabbit, and the other was comprised of African green monkey, cynomolgus monkey, Syrian hamster, Chinese hamster, guinea pig, dog, and chicken. The sensitivity of the PCR assay was at least 100 pg DNA/reaction, which was sufficient for the detection of each species of DNA. Furthermore, the nested PCR method was able to identify the species in the interspecies mixture of DNA. Thus, the method developed in this study will provide a useful tool for the authentication of animal species.

[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.