Clinical School (Austin Health) - Research Publications

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    Sodium bicarbonate infusion in patients undergoing orthotopic liver transplantation: a single center randomized controlled pilot trial
    Weinberg, L ; Broad, J ; Pillai, P ; Chen, G ; Nguyen, M ; Eastwood, GM ; Scurrah, N ; Nikfarjam, M ; Story, D ; McNicol, L ; Bellomo, R (WILEY-BLACKWELL, 2016-05)
    BACKGROUND: Liver transplantation-associated acute kidney injury (AKI) carries significant morbidity and mortality. We hypothesized that sodium bicarbonate would reduce the incidence and/or severity of liver transplantation-associated AKI. METHODS: In this double-blinded pilot RCT, adult patients undergoing orthotopic liver transplantation were randomized to an infusion of either 8.4% sodium bicarbonate (0.5 mEq/kg/h for the first hour; 0.15 mEq/kg/h until completion of surgery); (n = 30) or 0.9% sodium chloride (n = 30). PRIMARY OUTCOME: AKI within the first 48 h post-operatively. RESULTS: There were no significant differences between the two treatment groups with regard to baseline characteristics, model for end-stage liver disease and acute physiology and chronic health evaluation (APACHE) II scores, and pre-transplantation renal function. Intra-operative factors were similar for duration of surgery, blood product requirements, crystalloid and colloid volumes infused and requirements for vasoactive therapy. Eleven patients (37%) in the bicarbonate group and 10 patients (33%) in the sodium chloride group developed a post-operative AKI (p = 0.79). Bicarbonate infusion attenuated the degree of immediate post-operative metabolic acidosis; however, this effect dissipated by 48 h. There were no significant differences in ventilation hours, ICU or hospital length of stay, or mortality. CONCLUSIONS: The intra-operative infusion of sodium bicarbonate did not decrease the incidence of AKI in patients following orthotopic liver transplantation.
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    The haemodynamic effects of intravenous paracetamol (acetaminophen) in healthy volunteers: a double-blind, randomized, triple crossover trial
    Chiam, E ; Weinberg, L ; Bailey, M ; McNicol, L ; Bellomo, R (WILEY, 2016-04)
    AIM: The haemodynamic effects of intravenous paracetamol have not been systematically investigated. We compared the physiological effects of intravenous mannitol-containing paracetamol, and an equivalent dosage of mannitol, and normal saline 0.9% in healthy volunteers. METHODS: We performed a blinded, triple crossover, randomized trial of 24 adult healthy volunteers. Participants received i.v. paracetamol (1 g paracetamol +3.91 g mannitol 100 ml(-1) ), i.v. mannitol (3.91 g mannitol 100 ml(-1) ) and i.v. normal saline (100 ml). Composite primary end points were changes in mean arterial pressure (MAP), systolic blood pressure (SBP) and diastolic blood pressure (DBP) measured pre-infusion, during a 15 min infusion period and over a 45 min observation period. Systemic vascular resistance index (SVRI) and cardiac index were measured at the same time points. RESULTS: Infusion of paracetamol induced a transient yet significant decrease in blood pressures from pre-infusion values (MAP -1.85 mmHg, 95% CI -2.6, -1.1, SBP -0.54 mmHg, 95% CI -1.7, 0.6 and DBP -1.92 mmHg, 95% CI -2.6, -1.2, P < 0.0001), associated with a transient reduction in SVRI and an increase in cardiac index. Changes were observed, but to a lesser extent with normal saline (MAP -0.15 mmHg, SBP +1.44 mmHg, DBP --0.73 mmHg, P < 0.0001), but not with mannitol (MAP +1.47 mmHg, SBP +4.03 mmHg, DBP +0.48 mmHg, P < 0.0001). CONCLUSIONS: I.v. paracetamol caused a transient decrease in blood pressure immediately after infusion. These effects were not seen with mannitol or normal saline. The physiological mechanism was consistent with vasodilatation. This study provides plausible physiological data in a healthy volunteer setting, supporting transient changes in haemodynamic variables with i.v. paracetamol and justifies controlled studies in the peri-operative and critical care setting.
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    The impact of fluid intervention on complications and length of hospital stay after pancreaticoduodenectomy (Whipple's procedure)
    Weinberg, L ; Wong, D ; Karalapillai, D ; Pearce, B ; Tan, CO ; Tay, S ; Christophi, C ; McNicol, L ; Nikfarjam, M (BIOMED CENTRAL LTD, 2014-05-14)
    BACKGROUND: There is limited information on the impact on perioperative fluid intervention on complications and length of hospital stay following pancreaticoduodenectomy. Therefore, we conducted a detailed analysis of fluid intervention in patients undergoing pancreaticoduodenectomy at a university teaching hospital to test the hypothesis that a restrictive intravenous fluid regime and/or a neutral or negative cumulative fluid balance, would impact on perioperative complications and length of hospital stay. METHODS: We retrospectively obtained demographic, operative details, detailed fluid prescription, complications and outcomes data for 150 consecutive patients undergoing pancreaticoduodenectomy in a university teaching hospital. Prognostic predictors for length of hospital stay and complications were determined. RESULTS: One hundred and fifty consecutive patients undergoing pancreaticoduodenectomy were evaluated between 2006 and 2012. The majority of patients were, middle-aged, overweight and ASA class III. Postoperative complications were frequent and occurred in 86 patients (57%). The majority of complications were graded as Clavien-Dindo Class 2 and 3. Postoperative pancreatic fistula occurred in 13 patients (9%), and delayed gastric emptying occurred in 25 patients (17%). Other postoperative surgical complications included sepsis (22%), bile leak (4%), and postoperative bleeding (2%). Serious medical complications included pulmonary edema (6%), myocardial infarction (8%), cardiac arrhythmias (13%), respiratory failure (8%), and renal failure (7%). Patients with complications received a higher median volume of intravenous therapy and had higher cumulative positive fluid balances. Postoperative length of stay was significantly longer in patients with complications (median 25 days vs. 10 days; p < 0.001). After adjustment for covariates, a fluid balance of less than 1 litre on postoperative day 1 and surgeon caseloads were associated with the development of complications. CONCLUSIONS: In the context of pancreaticoduodenectomy, restrictive perioperative fluid intervention and negative cumulative fluid balance were associated with fewer complications and shorter length of hospital stay. These findings provide good opportunities to evaluate strategies aimed at improving perioperative care.
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    Perioperative blood management programme reduces the use of allogenic blood transfusion in patients undergoing total hip and knee arthroplasty
    Kopanidis, P ; Hardidge, A ; McNicol, L ; Tay, S ; McCall, P ; Weinberg, L (BMC, 2016-02-29)
    BACKGROUND: Optimisation of blood management in total hip (THA) and knee arthroplasty (TKA) is associated with improved patient outcomes. This study aimed to establish the effectiveness of a perioperative blood management programme in improving postoperative haemoglobin (Hb) and reducing the rate of allogenic blood transfusion. METHODS: This retrospective before and after study involves 200 consecutive patients undergoing elective TKA and THA before (Usual Care group) and after (Intervention group) the introduction of a blood management programme in an Australian teaching hospital. Patients in the Intervention group underwent preoperative treatment for anaemia and received intraoperative tranexamic acid (15 mg/kg). The primary outcomes were to compare postoperative Hb levels and the rate of blood transfusion. Secondary outcomes included measurements of total amount of allogenic blood transfused, transfusion-related complications, postoperative complications, need for inpatient rehabilitation and duration of hospital stay. RESULTS: There were no differences between baseline characteristics between groups. The mean (SD) preoperative Hb was higher in the Intervention group compared to that in the Usual Care group: 138.7 (13.9) vs. 133.4 (13.9) g/L, p = 0.008, respectively. The postoperative day 1 Hb, lowest postoperative Hb and discharge Hb were all higher in the Intervention group (p < 0.001). Blood transfusion requirements were lower in the Intervention group compared to the Usual Care group (6 vs. 20 %, p = 0.003). There were no differences in any of the secondary outcomes measured. Patients who were anaemic preoperatively and who underwent Hb optimisation had higher Hb levels postoperatively (odds ratio 5.7; 95 % CI 1.3 to 26.5; p = 0.024). CONCLUSIONS: The introduction of a perioperative blood optimisation programme improved postoperative Hb levels and reduced the rate of allogenic blood transfusion.
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    The effects on coagulation of the reinfusion of unprocessed residual blood from the cardiopulmonary bypass.
    Iyer, Y-L ; Hayward, P ; McNicol, L ; Weinberg, L (Springer Science and Business Media LLC, 2016-02-03)
    BACKGROUND: Autologous blood transfusion is a common technique in cardiac surgery to directly re-infuse residual blood from the cardiopulmonary bypass (CPB) circuit to the patient. The objective of this study was to evaluate the effects of reinfusion of unprocessed residual pump blood on the coagulation system after separation from the CPB circuit and reversal of systemic heparin with protamine. MEASUREMENTS AND MAIN RESULTS: After ethics approval, 40 participants undergoing cardiac surgery were recruited in a prospective single center cohort study. Changes in coagulation were assessed with standard plasma based laboratory assays and thromboelastography. After the reinfusion of unprocessed residual pump blood there were decreases in the mean aPTT (effect size 6 s; SD: 6.05; p < 0.0001) and thrombin time (effect size 4.08 s; SD: 9.7; p = 0.01). There were no significant changes in PT, INR and D-dimer. Post reinfusion there were increases in fibrinogen, hemoglobin and platelet counts. There were improvements in the R-time (effect size 9.1 s; SD: 16.9; p = 0.0023), K-time (effect size 1.5 s; SD: 3.6 s; p = 0.0017), alpha angle (6.9°; SD: 15.8; p = 0.012), and maximum amplitude (3.0 mm; SD: 5.6, p = 0.002) on thromboelastography. CONCLUSION: The reinfusion of unprocessed residual CPB blood resulted in no deleterious effects on the coagulation system measured by both the common laboratory plasma based measurements of coagulation and thromboelastography.
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    Comparative Evaluation of Crystalloid Resuscitation Rate in a Human Model of Compensated Haemorrhagic Shock
    Ho, L ; Lau, L ; Churilov, L ; Riedel, B ; McNicol, L ; Hahn, RG ; Weinberg, L (LIPPINCOTT WILLIAMS & WILKINS, 2016-08)
    INTRODUCTION: The most effective rate of fluid resuscitation in haemorrhagic shock is unknown. METHODS: We performed a randomized crossover pilot study in a healthy volunteer model of compensated haemorrhagic shock. Following venesection of 15 mL/kg of blood, participants were randomized to 20 mL/kg of crystalloid over 10 min (FAST treatment) or 30 min (SLOW treatment). The primary end point was oxygen delivery (DO2). Secondary end points included pressure and flow-based haemodynamic variables, blood volume expansion, and clinical biochemistry. RESULTS: Nine normotensive healthy adult volunteers participated. No significant differences were observed in DO2 and biochemical variables between the SLOW and FAST groups. Blood volume was reduced by 16% following venesection, with a corresponding 5% reduction in cardiac index (CI) (P < 0.001). Immediately following resuscitation the increase in blood volume corresponded to 54% of the infused volume under FAST treatment and 69% of the infused volume under SLOW treatment (P = 0.03). This blood volume expansion attenuated with time to 24% and 25% of the infused volume 30 min postinfusion. During fluid resuscitation, blood pressure was higher under FAST treatment. However, CI paradoxically decreased in most participants during the resuscitation phase; a finding not observed under SLOW treatment. CONCLUSION: FAST or SLOW fluid resuscitation had no significant impact on DO2 between treatment groups. In both groups, changes in CI and blood pressure did not reflect the magnitude of intravascular blood volume deficit. Crystalloid resuscitation expanded intravascular blood volume by approximately 25%.