ORCID Profile
0000-0002-1480-5956
Current Organisation
St Vincent's Hospital Melbourne
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Publisher: SAGE Publications
Date: 11-2011
DOI: 10.1177/0310057X1103900606
Abstract: This study compared the cardiac output responses to haemodynamic interventions as measured by three minimally invasive monitors (Oesophageal Doppler Monitor, the VigileoFlotrac and the LiDCOrapid) to the responses measured concurrently using thermodilution, in cardiac surgical patients. The study also assessed the precision and bias of these monitors in relation to thermodilution measurements. After a fluid bolus of at least 250 ml, the measured change in cardiac output was different among the devices, showing an increase with thermodilution in 82% of measurements, Oesophageal Doppler Monitor 68%, VigileoFlotrac 57% and LiDCOrapid 41%. When comparing the test devices to thermodilution, the kappa statistic showed at best only fair agreement, Oesophageal Doppler Monitor 0.34, LiDCOrapid 0.28 and VigileoFlotrac -0.03. After vasopressor administration, there was also significant variation in the change in cardiac output measured by the devices. Using Bland-Altman analysis, the precision of the devices in comparison to thermodilution showed minimal bias, but wide limits of agreement with percentage errors of Oesophageal Doppler Monitor 64.5%, VigileoFlotrac 47.6% and LiDCOrapid 54.2%. These findings indicate that these three devices differ in their responses, do not always provide the same information as thermodilution and should not be used interchangeably to track cardiac output changes.
Publisher: BMJ
Date: 2019
DOI: 10.1136/BMJOPEN-2018-023455
Abstract: Postoperative morbidity and mortality in older patients with comorbidities undergoing gastrointestinal surgery are a major burden on healthcare systems. Infections after surgery are common in such patients, prolonging hospitalisation and reducing postoperative short-term and long-term survival. Optimal management of perioperative intravenous fluids and inotropic drugs may reduce infection rates and improve outcomes from surgery. Previous small trials of cardiac-output-guided haemodynamic therapy algorithms suggested a modest reduction in postoperative morbidity. A large definitive trial is needed to confirm or refute this and inform widespread clinical practice. The Optimisation of Perioperative Cardiovascular Management to Improve Surgical Outcome II (OPTIMISE II) trial is a multicentre, international, parallel group, open, randomised controlled trial. 2502 high-risk patients undergoing major elective gastrointestinal surgery will be randomly allocated in a 1:1 ratio using minimisation to minimally invasive cardiac output monitoring to guide protocolised administration of intravenous fluid combined with low-dose inotrope infusion, or usual care. The trial intervention will be carried out during and for 4 hours after surgery. The primary outcome is postoperative infection of Clavien-Dindo grade II or higher within 30 days of randomisation. Participants and those delivering the intervention will not be blinded to treatment allocation however, outcome assessors will be blinded when feasible. Participant recruitment started in January 2017 and is scheduled to last 3 years, within 50 hospitals worldwide. The OPTIMISE II trial has been approved by the UK National Research Ethics Service and has been approved by responsible ethics committees in all participating countries. The findings will be disseminated through publication in a widely accessible peer-reviewed scientific journal. ISRCTN39653756 .
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1053/J.JVCA.2014.04.010
Abstract: To investigate whether the pleth variability index (PVI), derived noninvasively from a pulse oximeter probe, would predict fluid responsiveness in patients undergoing noncardiac surgeries. A clinical, prospective, observational study. Operating room of a tertiary care hospital. Twenty-nine adult patients undergoing a range of noncardiac surgeries, requiring general anesthesia, tracheal intubation, and mechanical ventilation. Intravenous volume expansion with 500 mL of colloid following induction of general anesthesia and after a period of hemodynamic stability before the start of surgery. Baseline values for PVI and stroke volume index, derived from an esophageal Doppler monitor, were compared with final values after the volume expansion. Patients were classified into fluid responders and nonresponders based on a stroke volume index increase of ≥ 10%. The optimal cut-off value for baseline pleth variability index for predicting fluid responsiveness was determined. There were 17 responders (59%) to the 500-mL volume expansion. Baseline PVI value was significantly different between responders and nonresponders (16.5 ± 6.4% v 10.3 ± 2.7% p = 0.004). Receiver operating characteristic analysis demonstrated significant predictive ability of an increase in stroke volume index for PVI with area under the curve of 0.84 (95% confidence interval = 0.69-0.99). The optimal cut-off value for baseline PVI was 10.5%, with a sensitivity of 88% and a specificity of 67%. Pleth variability index is predictive of fluid responsiveness in adult patients undergoing noncardiac surgery.
Publisher: SAGE Publications
Date: 26-04-2016
Abstract: Low-participation of culturally and linguistically erse (CALD) patients in medical research remains a problem in migrant and refugee destination countries such as Australia. The aims of this study were to explore i) CALD persons’ perceptions and experiences of the medical system and medical research, in this case, older Italian Australians and ii) the views of research professionals on CALD patient participation in medical research. A qualitative study was conducted in Melbourne, Australia, in 2015 utilising in-depth interviews and focus groups with four stakeholder groups: older Italian Australians (n=21) adult children of older Italian Australians (n=10) hospital Human Research Ethics Committee administrators (n=4) and clinical researchers (n=4). The data were analysed for content and thematic analysis. Themes for the CALD and family group were getting by in medical interactions receptivity to medical research: testing the waters and, receptivity to technology for support: passive versus active. Themes for the researcher and HREC groups about CALD patient participation in research were: exclusion cultural factors and e-consent. Our findings from four stakeholder perspectives and experiences confirm that there were considerable cultural, linguistic, and resourcing barriers hindering the participation of older Italian-Australians in medical research. Furthermore, our findings showed that in this study setting there were few enabling strategies in place to address these barriers despite the national ethics guidelines for equitable participation in research. The findings informed the creation of a multimedia tool whose purpose is to address and improve representation of CALD groups in clinical research.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Wiley
Date: 07-2016
DOI: 10.1111/IMJ.13089
Publisher: Springer Science and Business Media LLC
Date: 10-2014
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2008
Publisher: SAGE Publications
Date: 05-2016
DOI: 10.1177/0310057X1604400313
Abstract: There is lack of data about the agreement of minimally invasive cardiac output monitors, which make it impossible to determine if they are interchangeable or differ objectively in tracking physiological trends. We studied three commonly used devices: the oesophageal Doppler and two arterial pressure–based devices, the Vigileo FloTrac™ and LiDCOrapid™. The aim of this study was to compare the agreement of these three monitors in adult patients undergoing elective non-cardiac surgery. Measurements were taken at baseline and after predefined clinical interventions of fluid, metaraminol or ephedrine bolus. From 24 patients, 131 events, averaging 5.2 events per patient, were analysed. The cardiac index of LiDCOrapid versus FloTrac had a mean bias of −6.0% (limits of agreement from −51% to 39%) and concordance of over 80% to the three clinical interventions. The cardiac index of Doppler versus LiDCOrapid and Doppler versus FloTrac, had an increasing negative bias at higher mean cardiac outputs and there was significantly poorer concordance to all interventions. Of the preload-responsive parameters, Doppler stroke volume index, Doppler systolic flow time and FloTrac stroke volume variation were fair at predicting fluid responsiveness while other parameters were poor. While there is reasonable agreement between the two arterial pressure–derived cardiac output devices (LiDCOrapid and Vigileo FloTrac), these two devices differ significantly to the oesophageal Doppler technology in response to common clinical intraoperative interventions, representing a limitation to how interchangeable these technologies are in measuring cardiac output.
Publisher: SAGE Publications
Date: 2019
Abstract: Intravenous fluids are commonly administered for patients having colonoscopy despite relatively little data to support this practice. It is unclear what, if any, effect crystalloid administration has on stroke volume and cardiac output in patients who are fasting and have had bowel preparation agents. We aimed to assess the physiological effect of 10 ml/kg of crystalloid administration in colonoscopy patients on haemodynamic parameters including stroke volume, stroke volume variation and cardiac output, as measured with transthoracic echocardiography. Our secondary aims were to determine whether stroke volume variation predicted fluid responsiveness in gastrointestinal endoscopy patients and whether these haemodynamic measures are different in fasting patients with bowel preparation (colonoscopy patients) compared to fasting patients alone (gastroscopy patients). We recruited 54 patients having elective gastrointestinal endoscopy (25 colonoscopy, 29 gastroscopy). All patients had stroke volume, cardiac output and stroke volume variation measured with transthoracic echocardiography at baseline. In colonoscopy patients, stroke volume, cardiac output and stroke volume variation were remeasured after 10 ml/kg of intravenous crystalloid. Administration of 10 ml/kg of crystalloid increases stroke volume by 19.6 ml ( p 0.00005) and cardiac output by 0.81 l/min ( p 0.001). Stroke volume variation reduced from 23% to 14% after fluid administration ( p 0.0011). The optimum threshold of stroke volume variation to predict fluid responsiveness was 21% with a sensitivity of 77.8% and specificity of 62.5%. Administration of 10 ml/kg of crystalloid increases stroke volume and cardiac output, and reduces stroke volume variation in fasting elective colonoscopy patients.
Publisher: Wiley
Date: 29-11-2017
DOI: 10.1111/JCE.13107
Abstract: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. The significance of adenosine induced dormant pulmonary vein (PV) conduction in atrial fibrillation (AF) ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explored. ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. Consecutive patients undergoing index AF ablation received 3 adenosine doses (12, 18, and 24 mg) in a randomized blinded order, immediately after pulmonary vein isolation (PVI). Electrophysiological (PR prolongation, AV block (AVB) and PV reconnection) and hemodynamic (BP) parameters were measured. A total, 339 doses (113/dose) assessed 191 PVs in 50 patients (66% male, 72% PAF, 52% hypertensive). Dormant PV conduction occurred in 28% of patients (16.5% [32] of PVs). All cases were associated with AVB (AVB: PV reconnection vs. no PV reconnection 100% vs. 83%, P = 0.007). AVB occurred more frequently at 24 mg versus 12 mg (92% vs. 82%, P = 0.019) but not versus 18 mg (91%, P = 0.62). AVB duration progressed between 12 mg (12.0 ± 8.9 seconds), 18 mg (16.1 ± 9.1 seconds, P = 0.001), and 24 mg (19.0 ± 9.3 seconds, P < 0.001) doses. MBP fell further at 24 mg (ΔMBP: 27 ± 12 mmHg) and 18 mg (26 ± 13 mmHg) doses compared to 12 mg (22 ± 10 mmHg vs., P 110 kg (65% vs. 91% in 70-110 kg group, P 110 kg. Weight and dosing variability may in part explain the conflicting results of studies evaluating the clinical utility of adenosine in PVI.
Publisher: Wiley
Date: 03-11-2020
DOI: 10.1111/ANAE.15301
Abstract: Aerosol‐generating procedures such as tracheal intubation and extubation pose a potential risk to healthcare workers because of the possibility of airborne transmission of infection. Detailed characterisation of aerosol quantities, particle size and generating activities has been undertaken in a number of simulations but not in actual clinical practice. The aim of this study was to determine whether the processes of facemask ventilation, tracheal intubation and extubation generate aerosols in clinical practice, and to characterise any aerosols produced. In this observational study, patients scheduled to undergo elective endonasal pituitary surgery without symptoms of COVID‐19 were recruited. Airway management including tracheal intubation and extubation was performed in a standard positive pressure operating room with aerosols detected using laser‐based particle image velocimetry to detect larger particles, and spectrometry with continuous air s ling to detect smaller particles. A total of 482,960 data points were assessed for complete procedures in three patients. Facemask ventilation, tracheal tube insertion and cuff inflation generated small particles 30–300 times above background noise that remained suspended in airflows and spread from the patient’s facial region throughout the confines of the operating theatre. Safe clinical practice of these procedures should reflect these particle profiles. This adds to data that inform decisions regarding the appropriate precautions to take in a real‐world setting.
Publisher: Elsevier BV
Date: 02-1997
Abstract: Inositol phosphate release in intact heart in response to norepinephrine involves primarily release of inositol(1,4)bisphosphate (Ins(1,4)P2) rather than inositol(1,4,5)trisphosphate (Ins(1,4,5)P3) but Ins(1,4,5)P3 release predominates under conditions of post-ischemic reperfusion. In the current study, effects of myocardial ischemia on inositol phosphate responses were examined. Global myocardial ischemia in rat ventricle caused a reduction in the content of [3H]Ins(1,4)P3 (70-90%) and [3H]Ins(1,4,5)P3 (46%) and altered the pattern of norepinephrine stimulation such that increases in [3H]Ins(1,4,5)P3 were observed. Simulated ischemia in isolated right atria or isolated ventricular myocytes (P alpha 2 16-20 mmHg. pH 6.7. KCl 10 mM) produced similar changes. Reduction in O2 in the absence of other changes reduced the content of [3H]Ins (1,4)P2 (79%) in right atria whereas hypoxia and reduced pH were required to alter the [3H]Ins(1,4,5)P3 response. Progressive reduction in atrial ATP content using metabolic inhibitors caused a parallel decrease in [3H]Ins(1,4,5)P3 content (r = 0.96) without affecting [3H]Ins(1,4)P2 or the isomers of InsP1, showing that levels of Ins(1,4)P2 and Ins(1,4,5)P3 are regulated differently in the heart. These findings show that effects of ischemia on inositol phosphates in heart are complex and multifactorial, with Ins(1,4)P2 being affected under more moderately ischemic conditions than required for alterations in Ins(1,4,5)P3. These studies also demonstrate that ischemia produces similar effects on the release and metabolism of inositol phosphates in heart regardless of the ischemic model or the myocardial preparation used.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.HLC.2017.12.006
Abstract: Atrial fibrillation (AF) affects 1.5-2% of the population and is associated with a five-fold increased lifetime risk of stroke [1]. The left atrial appendage (LAA) is the source of embolic strokes in up to 90% of patients with non-valvular AF with clots in the left atrium [2]. We reviewed the clinical notes and echocardiographic findings of 20 patients who underwent open cardiac surgery in which concurrent AtriClip (Atricure Inc, Westchester, OH, USA) device insertion was attempted at our institution from July 2013 to February 2015. This was to examine the safety and efficacy of LAA exclusion with clip devices during open cardiac surgery. Indications for LAA exclusion included a history or suspicion of atrial arrhythmia, left ventricular dilatation, or a history of transient ischaemic attacks. All 20 of the 20 participants had successful placement of the clip device (100% success rate). There were no adverse events related to the device and no perioperative mortality. There were three late deaths due to chronic obstructive pulmonary disease (COPD), leukaemia, and refractory congestive cardiac failure. No late device related complications were found on follow-up imaging in the remaining patients. The results of our study demonstrate the LAA exclusion during open cardiac surgery with the AtriClip device is safe, has a 100% success rate, and appears to be stable over time.
Publisher: Springer Science and Business Media LLC
Date: 19-01-2021
Publisher: Springer Science and Business Media LLC
Date: 26-05-2016
Publisher: Public Library of Science (PLoS)
Date: 05-11-2020
DOI: 10.1371/JOURNAL.PONE.0239996
Abstract: A patient’s death can pose significant stress on the family and the treating anaesthetist. Anaesthetists’ attitudes about the benefits of and barriers to attending a patient’s funeral are unknown. Therefore, we performed a prospective, cross-sectional study to ascertain the frequency of anaesthetists’ attendance at a patient’s funeral and their perceptions about the benefits and barriers. The primary aim was to investigate the attitudes of anaesthetists towards attending the funeral of a patient. The secondary aims were to examine the perceived benefits of and barriers to attending the funeral and to explore the rate of bonds being formed between anaesthetists, patients and families. Of the 424 anaesthetists who completed the survey (response rate 21.2%), 25 (5.9%) had attended a patient’s funeral. Of the participants, 364 (85.9%) rarely formed special bonds with patients or their families 233 (55%) believed that forming a special bond would increase the likelihood of their attendance. Showing respect to patients or their families was the most commonly perceived benefit of attending a funeral. Participants found expression of personal grief and caring for the patient at the end-of-life and beyond beneficial to themselves and the family. Fear of their attendance being misinterpreted or perceived as not warranted by the family as well as time restraints were barriers for their attendance. Most anaesthetists had never attended a patient’s funeral. Few anaesthetists form close relationships with patients or their families. Respect, expression of grief and caring beyond life were perceived benefits of attendance. Families misinterpreting the purpose of attendance or not expecting their attendance and time restraints were commonly perceived barriers. Trial registration: ACTRN 12618000503224 .
Publisher: SAGE Publications
Date: 11-2014
DOI: 10.1177/0310057X1404200611
Abstract: There is continued controversy regarding the benefits of goal-directed fluid therapy, with earlier studies showing marked improvement in morbidity and length-of-stay that have not been replicated more recently. The aim of this study was to compare patient outcomes in elective colorectal surgery patients having goal-directed versus restrictive fluid therapy. Inclusion criteria included suitability for an Enhanced Recovery After Surgery care pathway and patients with an American Society of Anesthesiologists Physical Status score of 1 to 3. Patients were intraoperatively randomised to either restrictive or Doppler-guided goal-directed fluid therapy. The primary outcome was length-of-stay secondary outcomes included complication rate, change in haemodynamic variables and fluid volumes. One hundred patients, 50 in each group, were included in the analysis. Compared to restrictive therapy, goal-directed therapy resulted in a greater volume of intraoperative fluid, 2115 (interquartile range 1350 to 2560) ml versus 1500 (1200 to 2000) ml, P=0.008, and was associated with an increase in Doppler-derived stroke volume index from beginning to end of surgery, 43.7 (16.3) to 54.2 (21.1) ml/m 2 , P .001, in the latter group. Length-of-stay was similar, P=0.421. The number of patients with any complication (minor or major) was similar 60% (30) versus 52% (26), P=0.42, or major complications, 1 (2%) versus 4 (8%), P=0.36, respectively. The increased perioperative fluid volumes and increased stroke volumes at the end of surgery in patients receiving goal-directed therapy did not translate to a significant difference in length-of-stay and we did not observe a difference in the number of patients experiencing minor or major complications.
Publisher: Wiley
Date: 11-06-2014
DOI: 10.1111/ANAE.12758
No related grants have been discovered for Tuong Phan.