The Effect of Adjunctive Fresh Frozen Plasma Administration on Coagulation Parameters and Survival in a Canine Model of Antivenom-treated Brown Snake Envenoming

This study aimed to assess the effects of dugite envenoming on blood coagulation and platelet count in a canine model, and the efficacy of fresh frozen plasma (FFP) in reversing the clotting disorder after both adequate and inadequate venom neutralization. Following initial dosing and administration studies, an intravenous venom dose of 1μg/kg was administered to eleven dogs. This was followed 30 minutes later by antivenom in either adequate or inadequate doses. A further 30 minutes later, the animals were given either two units of their own FFP or saline. Fibrinogen, aPTT and platelet levels were monitored for eight hours.

Of the six study dogs given antivenom plus FFP, two died at around 60 to 90 minutes post envenoming, at the end of the FFP infusions, and all but one of the survivors had persistent afibrinogenaemia. Of the five study dogs given antivenom and no FFP, all but one had return of detectable fibrinogen at eight hours after envenoming. The platelet count fell in all animals with recovery independent of antivenom dose, administration of FFP, or regeneration of fibrinogen. Post mortem examinations of dogs that died during dosage and administration studies showed massive intracardiac clots.

We conclude that early death from Brown Snake envenoming may be due to massive intravascular clotting. FFP administration was associated with persistent afibrinogenaemia regardless of antivenom dose. In the absence of any evidence for its efficacy, this study suggests that the role of FFP after Brown Snake envenoming should be reconsidered.

Abstract P5-14-12: Cosmetic outcome is better after intraoperative radiotherapy compared with external beam radiotherapy: An objective assessment of patients from a randomized controlled trial

The randomised controlled TARGeted Intraoperative radioTherapy (TARGIT) Trial has demonstrated non-inferiority between the novel technique of TARGIT (intra-operative radiotherapy with Intrabeam ®) and conventional whole-breast external beam radiotherapy (EBRT) in women with early breast cancer, in terms of the primary outcome measure of risk of local relapse within the treated breast. As there are very low recurrence rates, cosmesis becomes an increasingly important outcome of breast conserving treatment with both surgery and radiotherapy. This study was performed to determine if the single high dose of TARGIT compared with EBRT leads to impaired cosmesis.

A validated, objective assessment software tool for evaluation of cosmetic outcome was used. Frontal digital photographs were taken at baseline (before radiotherapy) and annually thereafter for up to five years. The photographs were analysed by BCCT.core which produces a composite score based on symmetry, colour and scar.

A total of 342 patients were assessed, all over 50 years old with a median age at baseline of 64 years (IQR 59 to 68). The BCCT.core scores were dichotomised into Excellent and Good (EG), and Fair and Poor (FP). There were statistically significant increases in the odds of having an outcome of EG for patients in the TARGIT group compared with the EBRT group at year 1 (OR = 2.07, 95%CI 1.12 to 3.85, p = 0.021) and year 2 (OR = 2.11, 95%CI 1.0 to 4.45, p = 0.05).

This objective assessment of aesthetic outcome in patients from a randomised setting demonstrates that those treated with targeted intraoperative radiotherapy have a superior cosmetic result compared with those patients who received conventional whole-breast external beam radiotherapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-12.

Spontaneous abdominal wall endometriosis: a case report

Endometriosis is the presence of endometrial glands and stroma outside the uterus. Spontaneous abdominal wall endometriosis (AWE) is any ectopic endometrium found superficial to the peritoneum without the presence of any previous scar. Rarely, endometriosis represents a disease of specific interest to the general surgeon, on account of its extrapelvic localisations. We describe a case with spontaneous AWE presenting as a painful mass with cyclic symptoms. A 28-year-old woman presented to the day-surgery division of our department, suffering from a painful mass in the left lower abdominal quadrant. A mobile mass of 5 x 4 cm was identified. The initial diagnosis was lipoma and excision was planned. During the operation two masses were spotted, very close to one another, and were excised within healthy limits. Pathology revealed endometrial glands surrounded by a disintegrating mantle of endometrial stroma and fibrous scar tissue in which there was a scattering of leucocytes. The woman had no scars. She was discharged from hospital after 2 hours. Two years after the excision she is free of disease and no recurrence has been observed. Spontaneous AWE is rare, accounting for 20% of all AWEs. The triad ; mass, pain and cyclic symptomatology helps in the diagnosis, but unfortunately it is not present in all cases. Spontaneous endometriomas are usually diagnosed by pathology and the treatment of choice is surgical excision.

The effects of recent aspirin ingestion on platelet function in cardiac surgical patients

OBJECTIVE

To examine the effects of the preoperative aspirin-free interval on platelet function in cardiac surgical patients.

DESIGN

Prospective clinical investigation.

SETTING

University-affiliated teaching hospital.

PARTICIPANTS

Patients undergoing elective coronary artery bypass graft surgery (n = 100).

INTERVENTIONS

The patients were divided into 3 groups based on the number of days since they last ingested aspirin: < or =2 days, 3 to 7 days, and >7 days. Preoperative platelet function was assessed in all patients using platelet aggregation responses to arachidonic acid, 5 microg/mL, and Platelet Function Analyser (PFA100) collagen/epinephrine closure times.

MEASUREMENTS AND MAIN RESULTS

Patients who ceased aspirin < or =2 days preoperatively had weaker platelet aggregation responses (18.5% +/- 7% maximum aggregation, mean +/- SD, n = 36) than patients who ceased aspirin 3 to 7 days preoperatively (68.8% +/- 29%, n = 48, p < 0.001) or >7 days preoperatively (68.3% +/- 28%, n = 16, p < 0.001). Similarly, patients who ceased aspirin < or =2 days preoperatively had longer PFA100 closure times (168 +/- 52 sec) than patients who ceased aspirin 3 to 7 days preoperatively (122 +/- 43 sec, p < 0.001) or >7 days preoperatively (128 +/- 42 sec, p < 0.01). The percentage of abnormal responses was also greatest in the aspirin < or =2 days group.

CONCLUSION

Cardiac surgical patients who ingest aspirin < or =2 days preoperatively have greater impairment of platelet function than patients who have a longer preoperative aspirin-free interval.

Dose-response to inhaled aerosolized prostacyclin for hypoxemia due to ARDS

STUDY OBJECTIVES

This study was carried out to determine the efficacy of and dose-response relationships to inhaled aerosolized prostacyclin (IAP), when used as a selective pulmonary vasodilator (SPV) in patients with severe hypoxemia due to ARDS.

DESIGN

Unblinded, interventional, prospective clinical study.

SETTING

A general ICU in a university-affiliated, tertiary referral center.

PATIENTS

Nine adult patients with severe ARDS (lung injury score, > or = 2.5).

INTERVENTIONS

All patients received IAP over the dose range 0 to 50 ng/kg/min. The IAP was delivered via a jet nebulizer placed in the ventilator circuit. Dose increments were 10 ng/kg/min every 30 min.

MEASUREMENTS AND RESULTS

Cardiovascular parameters (cardiac index and mean pulmonary and systemic pressures), indexes of oxygenation (PaO(2)/fraction of inspired oxygen [FIO(2)] ratio and alveolar-arterial oxygen partial pressure difference [P(A-a)O(2)]) and shunt fraction were measured or calculated at each dose interval, as were platelet aggregation and systemic levels of prostacyclin metabolite (6-keto prostaglandin F1(alpha)). A generalized linear regression model was used to determine a dose effect of IAP on these parameters. The Wilcoxon rank sum test for related measures was used to compare the effects of various doses of IAP. IAP acted as an SPV, with a statistically significant dose-related improvement in PaO(2)/FIO(2) ratio (p = 0.003) and P(A-a)O(2) (p = 0.01). Systemic prostacyclin metabolite levels increased significantly in response to delivered IAP (p = 0.001). There was no significant dose effect on systemic or pulmonary arterial pressures, or on platelet function, as determined by platelet aggregation in response to challenge with adenosine diphosphate.

CONCLUSIONS

IAP is an efficacious SPV, with marked dose-related improvement in oxygenation and with no demonstrable effect on systemic arterial pressures over the dose range 0 to 50 ng/kg/min. Despite significant systemic levels of prostacyclin metabolite, there was no demonstrable platelet function defect.

Evaluation of the TAS coagulation analyzer for monitoring heparin effect in cardiac surgical patients

OBJECTIVE

To assess the relationship between the Thrombolytic Assessment System (TAS); (Cardiovascular Diagnostics, Inc, Raleigh, NC) measurements and heparin levels in cardiac surgical patients.

DESIGN

Equipment evaluation in vitro and in vivo.

SETTING

A university teaching hospital.

PARTICIPANTS

Sixty adult patients undergoing elective cardiac surgery requiring cardiopulmonary bypass (CPB).

INTERVENTIONS

Part 1: Simultaneous heparin management tests (HMTs) and activated coagulation times (ACTs) were measured in 20 patients pre-CPB, during CPB, and post-CPB. In the same patients, the effect of heparin, 1 to 5 IU/mL, on the HMT was assessed in vitro. The effect of aprotinin, 50 to 200 KIU/mL, on the HMT, was assessed in vitro in a further 10 patients. Part II: Simultaneous TAS and laboratory (LAB) activated partial thromboplastin times (APTTs) were measured pre-CPB and post-CPB in 20 patients. In the same patients, the effect of heparin, 0.1 to 0.5 IU/mL, on the TAS APTT was assessed in vitro. The effect of aprotinin on the TAS APTT was assessed in vitro in a further 10 patients.

MAIN RESULTS

Part I: Heparin, 0, 1, 2, and 5 IU/mL in vitro resulted in HMTs of 164 +/- 12, 281 +/- 19, 338 +/- 16, and 436 +/- 33 seconds (mean +/- standard deviation [SD]), respectively. The HMT had less variability than the ACT in vivo. Part II: Heparin, 0, 0.1, 0.2, and 0.5 IU/mL in vitro, resulted in TAS APTTs of 34.9 +/- 4.7, 61.2 +/- 2.5, 97.4 +/- 34.7, and 197.1 +/- 64.3 seconds, respectively. The correlation (r) between the TAS and LAB APTT was 0.726 pre-CPB and 0.794 post-CPB. Aprotinin increased both the HMT and TAS APTT in a dose-related manner.

CONCLUSION

The TAS may be a useful monitor of heparin effect in cardiac surgical patients.

Respiratory complications after coronary artery bypass surgery with unilateral or bilateral internal mammary artery grafting

BACKGROUND AND STUDY OBJECTIVE

Use of bilateral internal mammary artery (IMA) grafts during coronary artery revascularization procedures carries the potential for increased incidence of postoperative respiratory complications compared with use of unilateral IMA grafts. The purpose of this study was to compare the incidence of respiratory complications such as hypoxemia, atelectasis, pleural effusion, and diaphragmatic dysfunction in patients who received one or both IMAs as conduit grafts.

DESIGN

Prospective, comparative study.

SETTING

Surgical ICU at a tertiary teaching hospital.

PATIENTS

Seventy-five patients with bilateral and 75 patients with unilateral IMA grafts.

MEASUREMENTS

Serial postoperative PaO2/fraction of inspired oxygen measurements, radiographic scores of atelectasis and pleural effusion, duration of mechanical ventilation, length of ICU and hospital stay, and incidence of pneumothorax, pneumonia, and wound infection.

RESULTS

There was a higher incidence (51% vs 25%; p=0.002) and severity (0.48+/-0.09 vs 0.15+/-0.05 on the first postoperative day, 0.39+/-0.07 vs 0.27+/-0.07 on the fourth postoperative day, mean+/-SEM; p=0.004) of postoperative right lower lobe atelectasis in the group who received bilateral IMA grafts than in those who received left IMA grafts. This finding probably reflects the effects of additional surgical intervention on the right side of the chest. Incidence and severity of pleural effusion, gas exchange impairment, duration of mechanical ventilation, ICU and hospital stay, and incidence of pneumothorax, pneumonia, and wound infection were not influenced by use of bilateral IMA grafts (p>0.05).

CONCLUSION

We conclude that use of bilateral IMA grafts during coronary artery revascularization does not increase the incidence of postoperative respiratory complications compared with unilateral IMA grafting.

Effect of low concentrations of prostacyclin on platelet function in vitro

The study was performed to determine the possible direct effects of low concentrations of prostacyclin that might spill over into the systemic circulation during the administration of inhaled aerosolized prostacyclin. Platelet aggregation in response to adenosine diphosphate and collagen, as well as measurement of the maximum amplitude of the thrombelastograph (TEG), was undertaken in vitro using venous blood exposed to low concentrations of prostacyclin (0, 10, 100 and 500 pg/ml) from eight healthy volunteers. There were statistically significant reductions in parameters of platelet aggregation in response to the agonists adenosine diphosphate (1 mumol/l and 8 mumol/l) and collagen (10 mumol/l) following exposure to as little as 10 pg/ml of prostacyclin. The maximum amplitude of the TEG was unchanged over the entire range of prostacyclin concentrations studied. The results indicate that low concentrations of prostacyclin or prostacyclin metabolite such as may be observed during inhaled aerosolized prostacyclin therapy are likely to be associated with a marked platelet aggregation defect. This defect was not detected by the TEG.

A comparison of postoperative thrombotic potential following abdominal aortic surgery, carotid endarterectomy, and femoro-popliteal bypass

Postoperative changes in procoagulant, anticoagulant, and antifibrinolytic factors were compared in patients undergoing abdominal aortic surgery, carotid endarterectomy, and femoro-popliteal bypass. There were increases in plasma fibrinogen (P < 0.01) and factor VIII coagulant (P < 0.01) levels following all three procedures. There were decreases in antithrombin III (P < 0.01) and protein C (P < 0.01), and increases in thrombin-antithrombin complex levels (P < 0.01) in the abdominal aortic group only. There were no significant changes in type 1 plasminogen activator inhibitor levels following any of the procedures. The results indicate that all three procedures are associated with an increased potential for thrombosis due to increases in procoagulant factors. However, patients undergoing abdominal aortic surgery are particularly at risk due to concurrent decreases in natural anticoagulant factors. Specific antithrombotic therapy should be considered for all patients undergoing vascular surgery, but particularly for those undergoing major procedures such as abdominal aortic surgery.

Thrombelastographic patterns following abdominal aortic surgery

Postoperative changes in thrombelastographic patterns were studied in thirty patients undergoing elective abdominal aortic bypass surgery. Native whole blood thrombelastography was performed preoperatively and on days 1, 2, and 3 postoperatively. The thrombelastographic changes included a decrease in r on day one (P < 0.0001), with concurrent increases in alpha (P < 0.0001) and MA (P < 0.001). On days 2 and 3 there were further increases in MA (P < 0.0001). These changes indicate enhanced procoagulant activity and progressive increases in maximum clot strength. The results confirm that hypercoagulability occurs in whole blood following abdominal aortic bypass surgery. Further studies are warranted to determine whether modification of postoperative hypercoagulability reduces the incidence of thrombotic complications in this group of patients.

Postoperative changes in coagulant and anticoagulant factors following abdominal aortic surgery

The extent and time course of changes in selected procoagulant and anticoagulant factors were investigated in 19 patients undergoing elective abdominal aortic surgery. The coagulation factors were measured preoperatively, and on days two, four, and six postoperatively. It was found that there were no significant changes outside the normal range in prothrombin time, partial thromboplastin time, or thrombin clotting time. However, there were large increases in the procoagulants, fibrinogen, factor VIII coagulant, factor VIIIRag/von Willebrand factor, and in alpha 1-antitrypsin. Over the same time there were marked decreases in the naturally occurring anticoagulants, protein C and antithrombin III, and in alpha 2-macroglobulin. These changes implied that the patients were "hypercoagulable" in the postoperative period. The maximum changes in the procoagulants occurred on either postoperative day two or day four. The maximum changes in the natural anticoagulants occurred on postoperative day two. There were no significant changes in factor V, factor X, alpha 2-antiplasmin, or platelet aggregability. The timing of the changes coincided with a period of high risk of perioperative myocardial infarction in this group of patients. Thus, it is possible that postoperative hypercoagulability contributes to the development of coronary artery thrombosis and myocardial infarction following abdominal aortic surgery.

The effect of epidural blockade on postoperative hypercoagulability following abdominal aortic bypass surgery

The effect of epidural blockade on postoperative hypercoagulability was assessed in patients undergoing elective abdominal aortic bypass surgery. Twenty patients were randomised to receive general anaesthesia alone, or general anaesthesia plus thoracic epidural blockade with 0.5% bupivacaine. It was found that the addition of epidural blockade did not alter the postoperative increase in plasma fibrinogen, factor VIII coagulant, or alpha 1-antitrypsin. Similarly, epidural blockade did not affect the postoperative decrease in antithrombin III. The results suggest that epidural blockade with local anaesthetic agents does not prevent the postoperative hypercoagulability response following abdominal aortic bypass surgery.

Treatment of neovascularization secondary to branch retinal vein obstruction

Fifty patients who developed preretinal or papillary neovascularization following tributary vein occlusion were treated by laser photocoagulation. Areas of non-perfused retina within the distribution of the obstructed vein were identified by fluorescein angiography and ablated using moderately intense laser photocoagulation burns. In forty-six patients there was satisfactory atrophy of both preretinal and papillary neovascularization without further complication or vitreous haemorrhage. Four patients who responded poorly to laser photocoagulation did so either because areas of ischaemic retina were inadequately treated or because they were unamenable to laser photocoagulation e.g., sited in the parafoveal region. Ablation of ischaemic perimacular retina together with associated intraretinal microvascular abnormalities aided the resolution of macular oedema in 19 patients. No post-operative complications could be attributed to laser photocoagulation excepting the development of fine perimacular retinal folds in one patient.