Clinical School (Austin Health) - Research Publications
Now showing items 1-12 of 61
Relationship between urinary sodium-to-potassium ratio and ambulatory blood pressure in patients with diabetes mellitus
Previous studies investigating the relationship between sodium intake and blood pressure have mostly relied on dietary recall and clinic blood pressure measurement. In this cross-sectional study, we aimed to investigate the relationship between 24 hour urinary sodium and potassium excretion, and their ratio, with 24 hour ambulatory blood pressure parameters including nocturnal blood pressure dipping in patients with type 1 and 2 diabetes. We report that in 116 patients with diabetes, systolic blood pressure was significantly predicted by the time of day, age, the interaction between dipping status with time, and 24 hour urinary sodium-to-potassium ratio (R2 = 0.83) with a relative contribution of 53%, 21%, 20% and 6%, respectively. However, there was no interaction between urinary sodium-to-potassium ratio and dipping status.
Serum carbohydrate antigen 19-9 in pancreatic adenocarcinoma: a mini review for surgeons
The optimal management of oncological conditions is reflected by the careful interpretation of investigations for screening, diagnosis, staging, prognostication and surveillance. Serum tumour markers are examples of commonly requested tests in conjunction with other imaging and endoscopic tests that are used to help clinicians to stratify therapeutic decisions. Serum carbohydrate antigen 19-9 (CA19-9) is a key biomarker for pancreatic cancers. Although this biomarker is considered clinically useful and informative, clinicians are often challenged by the accurate interpretation of elevated serum CA19-9 levels. Recognizing the pitfalls of normal and abnormal serum CA19-9 concentrations will facilitate its appropriate use. In this review, we appraised the biomarker, serum CA19-9, and highlighted the clinical utility and limitations of serum CA19-9 in the investigation and management of pancreatic cancers.
Analysis of tenodesis techniques for treatment of scapholunate instability using the finite element method.
Chronic scapholunate ligament (SL) injury is a common disorder affecting the wrist. Despite advances in surgical techniques used to treat this injury, SL gap re-emergence may occur postoperatively. This paper presents an investigation into the performance of the Corella, schapolunate axis (SLAM), and modified Brunelli tenodesis (MBT) surgical reconstruction techniques used to treat scapholunate instability. Finite element (FE) models were used to undertake virtual surgery, and the resulting scapholunate (SL) gap and angle obtained using the 3 techniques were compared. The Corella technique was found to achieve the SL gap and angle closest to the intact (ligament) wrist, restoring SL gap and angle to within 5.6% and 0.6%, respectively. The MBT method resulted in an SL gap least close to the intact. The results of our study indicate that the contribution of volar scapholunate interosseous ligament to scapholunate stability could be important.
Temporal lobe epilepsy following maintenance electroconvulsive therapyElectrical kindling in the human brain?
Maintenance electroconvulsive therapy (ECT) is sometimes prescribed for refractory psychiatric conditions. We describe five patients who received maintenance ECT and developed florid temporal epileptiform abnormalities on electroencephalography (EEG) despite no history of epilepsy and normal neuroimaging. All patients had received regular ECT for at least 8 months. Three patients had clinical events consistent with epileptic seizures, and video-EEG monitoring captured electrographic seizures in two patients. After cessation of ECT the EEGs normalized in all patients, and no further clinical seizures occurred. Maintenance ECT may predispose to epilepsy with a seizure focus in the temporal lobe.
Sodium bicarbonate infusion in patients undergoing orthotopic liver transplantation: a single center randomized controlled pilot trial
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.
The haemodynamic effects of intravenous paracetamol (acetaminophen) in healthy volunteers: a double-blind, randomized, triple crossover trial
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.
Predictors of Manuscript Rejection sYndrome (MiSeRY): a cohort study
OBJECTIVES: To assess whether specific factors predict the development of ManuScript Rejection sYndrome (MiSeRY) in academic physicians. DESIGN: Prospective pilot study; participants self-administered a questionnaire about full manuscript submissions (as first or senior author) rejected at least once during the past 5 years. SETTING: Single centre (tertiary institution). PARTICIPANTS: Eight academic physician-authors. MAIN OUTCOME MEASURES: Duration of grief. MiSeRY was pre-specified as prolonged grief (grief duration longer than the population median). RESULTS: Eight participants provided data on 32 manuscripts with a total of 93 rejections (median, two rejections per manuscript; interquartile range [IQR], 1-3 rejections per manuscript). Median age at rejection was 37 years (IQR, 33-45 years); 86% of 80 rejections involved male authors (86%), 56 of the authors providing data about these rejections were first authors (60%). The median journal impact factor was 5.9 (IQR, 5.2-17). In 48 cases of rejection (52%), pre-submission expectations of success had been high, and in 54 cases (58%) the manuscripts had been sent for external review. Median grief duration was 3 hours (IQR, 1-24 h). Multivariate analysis indicated that higher pre-submission expectation (adjusted odds ratio [aOR], 5.0; 95% CI, 1.5-18), first author status (aOR, 9.5; 95% CI, 1.1-77), and external review (aOR, 19.0; 95% CI 2.9-126) were independent predictors of MiSeRY. CONCLUSIONS: To help put authors out of their MiSeRY, journal editors could be more selective in the manuscripts they send for external review. Tempering pre-submission expectations and mastering the Coping and reLaxing Mechanisms (CaLM) of senior colleagues are important considerations for junior researchers.
Intra-operative cell salvage in urological surgery: a systematic review and meta-analysis of comparative studies
OBJECTIVE: To evaluate systematically the safety and efficacy of intra-operative cell salvage (ICS) in urology. METHODS: A search of Medline, Embase and Cochrane Library to August 2017 was performed using methods pre-published on PROSPERO. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. Eligible titles were comparative studies published in English that used ICS in urology. Primary outcomes were allogeneic transfusion rates (ATRs) and tumour recurrence. Secondary outcomes were complications and cost. RESULTS: Fourteen observational studies were identified, with a total of 4 536 patients. ICS was compared with no the blood conservation technique (seven studies), preoperative autologous donation (PAD; five studies) or both (two studies). Cohorts underwent open prostatectomy (11 studies), open cystectomy (two studies) or open partial nephrectomy (one study). Meta-analysis was possible only for ATRs within prostatectomy studies. In this setting, ICS reduced ATR compared with no the blood conservation technique (odds ratio [OR] 0.34, 95% confidence interval [CI] 0.15-0.76) but not PAD (OR 0.76, 95% CI 0.39-1.31). In the non-prostatectomy setting, ATRs amongst patients who underwent ICS were significantly higher or similar in one and two studies, respectively. Tumour recurrence was found to be significantly less common (two studies), similar (eight studies) or not measured (four studies). All six studies reporting complications found no difference in their ICS cohorts. Regarding cost, one study from 1995 found ICS more expensive than PAD, while two more recent studies found ICS to be cheaper than no blood conservation technique. As a result of inter-study heterogeneity, meta-analyses were not possible for recurrence, complications or cost. CONCLUSION: Low-level evidence exists that, compared with other blood conservation techniques, ICS reduces ATR and cost while not affecting complications. It does not appear to increase tumour recurrence post-prostatectomy, although follow-up durations were short. Small study sizes and short follow-ups mean conclusions cannot be drawn with regard to recurrence after nephrectomy or cystectomy. Randomized trials with long-term follow-up evaluating ICS in urology are required.
Design considerations for an eHealth decision support tool in inflammatory bowel disease self-management
BACKGROUND: Electronic health (eHealth) decision support tools have the potential to: facilitate inflammatory bowel disease (IBD) self-management, reduce health care utilisation and alleviate the pressure on overburdened outpatient clinics. The purpose of this study was to explore the perspectives of key stakeholders on the potential use of a decision support tool for IBD patients. METHODS: A qualitative study using focus group methodology was conducted at a tertiary IBD centre in Melbourne, Australia in February 2015. Key stakeholders, including physicians, nurses and patients, were included in the study. Two independent reviewers undertook inductive coding and generated themes. RESULTS: In total, 31 participants were included in the study (including 16 males; 11 physicians; 6 nurses). An eHealth decision support tool was thought to be beneficial to facilitate IBD self-management. Four themes emerged: (i) Framework for the decision support tool - the tool should be an adjunct to current models of care and facilitate shared decision-making and patient engagement; (ii) Target population - stable patients with mild to moderate disease; (iii) Functionalities of the intervention - a web-based platform encompassing patient-reported outcomes, objective markers of disease and clinical algorithms based on international guidelines; and (iv) Design and Implementation - patients should be involved in the design. CONCLUSIONS: eHealth interventions are thought to be an important strategy to facilitate self-management for patients with IBD. A multi-stage iterative approach should be adopted in the design and implementation process of eHealth interventions. Patient perspectives need to be sought prior to and throughout the development of an eHealth decision support tools for IBD.
Radiotherapy-related complications presenting to a urology department: a more common problem than previously thought?
OBJECTIVE: To quantify the burden of the side effects of radiotherapy on a tertiary referral urology department. PATIENTS AND METHODS: A prospective study of all urology admissions to a public urology department at a tertiary hospital in a 6-month period was performed. Patients admitted with complications attributable to radiotherapy were included in the study. Data obtained included patient demographics, radiotherapy details, complication type and management required. RESULTS: A total of 1198 patients were admitted; 921 (77%) were elective and 277 (23%) were emergency admissions. Thirteen out of the 921 (1.4%) elective admissions and 20 out of the 277 (7.2%) emergency admissions were attributable to radiotherapy complications. Radiotherapy complications was the fourth most common reason for emergency admission, ahead of acute urinary retention. These 33 admissions were accounted for by 21 patients. A total of 39 separate complications attributable to radiotherapy were diagnosed, with some patients having multiple complications. The median (interquartile range) time to onset of complications was 4 (1-9) years. The surgical intervention rate was 67%. The commonest procedures were washout with/without clot evacuation or diathermy in theatre (15.8%) and urethral dilatation/bladder neck incision (15.8%). Two urinary diversions and two cystoprostatectomies plus urinary diversion were performed. CONCLUSION: Radiotherapy complications are consequential and account for a substantial proportion of a tertiary urology department's emergency workload. These complications generally occur years after radiotherapy and frequently require surgical intervention.
Effect of QT interval prolongation on cardiac arrest following liver transplantation and derivation of a risk index
Liver transplantation (LT) has a 4-fold higher risk of periprocedural cardiac arrest and ventricular arrhythmias (CA/VAs) compared with other noncardiac surgeries. Prolongation of the corrected QT interval (QTc) is common in patients with liver cirrhosis. Whether it is associated with an increased risk of CA/VAs following LT is unclear. Rates of 30-day CA/VAs post-LT were assessed in consecutive adults undergoing LT between 2010 and 2017. Pretransplant QTc was measured by a cardiologist blinded to clinical outcomes. Among 408 patients included, CA/VAs occurred in 26 patients (6.4%). QTc was significantly longer in CA/VA patients (475 ± 34 vs 450 ± 34 ms, P < .001). Optimal QTc cut-off for prediction of CA/VAs was ≥480 ms. After adjustment, QTc ≥480 ms remained the strongest predictor for the occurrence of CA/VAs (odds ratio [OR] 5.2, 95% confidence interval [CI] 2.2-12.6). A point-based cardiac arrest risk index (CARI) was derived with the bootstrap method for yielding optimism-corrected coefficients (2 points: QTc ≥480, 1 point: Model for End-Stage Liver Disease [MELD] ≥30, 1 point: age ≥65, and 1 point: male). CARI score ≥3 demonstrated moderate discrimination (c-statistic 0.79, optimism-corrected c-statistic 0.77) with appropriate calibration. QTc ≥480 ms was associated with a 5-fold increase in the risk of CA/VAs. The CARI score may identify patients at higher risk of these events. Whether heightened perioperative cardiac surveillance, avoidance of QT prolonging medications, or beta blockers could mitigate the risk of CA/VAs in this population merits further study.