Medicine (Austin & Northern Health) - Research Publications
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ItemNo Preview AvailableMild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest(MASSACHUSETTS MEDICAL SOC, 2023-07-06)BACKGROUND: Guidelines recommend normocapnia for adults with coma who are resuscitated after out-of-hospital cardiac arrest. However, mild hypercapnia increases cerebral blood flow and may improve neurologic outcomes. METHODS: We randomly assigned adults with coma who had been resuscitated after out-of-hospital cardiac arrest of presumed cardiac or unknown cause and admitted to the intensive care unit (ICU) in a 1:1 ratio to either 24 hours of mild hypercapnia (target partial pressure of arterial carbon dioxide [Paco2], 50 to 55 mm Hg) or normocapnia (target Paco2, 35 to 45 mm Hg). The primary outcome was a favorable neurologic outcome, defined as a score of 5 (indicating lower moderate disability) or higher, as assessed with the use of the Glasgow Outcome Scale-Extended (range, 1 [death] to 8, with higher scores indicating better neurologic outcome) at 6 months. Secondary outcomes included death within 6 months. RESULTS: A total of 1700 patients from 63 ICUs in 17 countries were recruited, with 847 patients assigned to targeted mild hypercapnia and 853 to targeted normocapnia. A favorable neurologic outcome at 6 months occurred in 332 of 764 patients (43.5%) in the mild hypercapnia group and in 350 of 784 (44.6%) in the normocapnia group (relative risk, 0.98; 95% confidence interval [CI], 0.87 to 1.11; P = 0.76). Death within 6 months after randomization occurred in 393 of 816 patients (48.2%) in the mild hypercapnia group and in 382 of 832 (45.9%) in the normocapnia group (relative risk, 1.05; 95% CI, 0.94 to 1.16). The incidence of adverse events did not differ significantly between groups. CONCLUSIONS: In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia. (Funded by the National Health and Medical Research Council of Australia and others; TAME ClinicalTrials.gov number, NCT03114033.).
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ItemHospital-acquired complications in intensive care unit patients with diabetes: A before-and-after study of a conventional versus liberal glucose control protocol(WILEY, 2019-07)BACKGROUND: Critically ill patients with diabetes mellitus (DM) are at increased risk of in-hospital complications and the optimal glycemic target for such patients remains unclear. A more liberal approach to glucose control has recently been suggested for patients with DM, but uncertainty remains regarding its impact on complications. METHODS: We aimed to test the hypothesis that complications would be more common with a liberal glycemic target in ICU patients with DM. Thus, we compared hospital-acquired complications in the first 400 critically ill patients with DM included in a sequential before-and-after trial of liberal (glucose target: 10-14 mmol/L) vs conventional (glucose target: 6-10 mmol/L) glucose control. RESULTS: Of the 400 patients studied, 165 (82.5%) patients in the liberal and 177 (88.5%) in the conventional-control group were coded for at least one hospital-acquired complication (P = 0.09). When comparing clinically relevant complications diagnosed between ICU admission and hospital discharge, we found no difference in the odds for infectious (adjusted odds ratio [aOR] for liberal-control: 1.15 [95% CI: 0.68-1.96], P = 0.60), cardiovascular (aOR 1.40 [95% CI: 0.63-3.12], P = 0.41) or neurological complications (aOR: 1.07 [95% CI: 0.61-1.86], P = 0.81), acute kidney injury (aOR 0.83 [95% CI: 0.43-1.58], P = 0.56) or hospital mortality (aOR: 1.09 [95% CI: 0.59-2.02], P = 0.77) between the liberal and the conventional-control group. CONCLUSION: In this prospective before-and-after study, liberal glucose control was not associated with an increased risk of hospital-acquired infectious, cardiovascular, renal or neurological complications in critically ill patients with diabetes.
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ItemWhat Happens to Nutrition Intake in the Post-Intensive Care Unit Hospitalization Period? An Observational Cohort Study in Critically Ill Adults(WILEY, 2019-01)BACKGROUND: Little is currently known about nutrition intake and energy requirements in the post-intensive care unit (ICU) hospitalization period in critically ill patients. We aimed to describe energy and protein intake, and determine the feasibility of measuring energy expenditure during the post-ICU hospitalization period in critically ill adults. METHODS: This is a nested cohort study within a randomized controlled trial in critically ill patients. After discharge from ICU, energy and protein intake was quantified periodically and indirect calorimetry attempted. Data are presented as n (%), mean (SD), and median (interquartile range [IQR]). RESULTS: Thirty-two patients were studied in the post-ICU hospitalization period, and 12 had indirect calorimetry. Mean age and BMI was 56 (18) years and 30 (8) kg/m2 , respectively, 75% were male, and the median estimated energy and protein requirement were 2000 [1650-2550] kcal and 112 [84-129] g, respectively. Oral nutrition either alone (n = 124 days, 55%) or in combination with enteral nutrition (n = 96 days, 42%) was the predominant mode. Over 227 total days in the post-ICU hospitalization period, a median [IQR] of 1238 [869-1813] kcal and 60 [35-89.5] g of protein was received from nutrition therapy. In the 12 patients who had indirect calorimetry, the median measured daily energy requirement was 1982 [1843-2345] kcal and daily energy deficit was -95 [-1050 to 347] kcal compared with the measured energy requirement. CONCLUSIONS: Energy and protein intake in the post-ICU hospitalization period was less than estimated and measured energy requirements. Oral nutrition provided alone was the most common mode of nutrition therapy.
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ItemEffect of Vitamin C, Hydrocortisone, and Thiamine vs Hydrocortisone Alone on Time Alive and Free of Vasopressor Support Among Patients With Septic Shock The VITAMINS Randomized Clinical Trial(AMER MEDICAL ASSOC, 2020-02-04)IMPORTANCE: It is unclear whether vitamin C, hydrocortisone, and thiamine are more effective than hydrocortisone alone in expediting resolution of septic shock. OBJECTIVE: To determine whether the combination of vitamin C, hydrocortisone, and thiamine, compared with hydrocortisone alone, improves the duration of time alive and free of vasopressor administration in patients with septic shock. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, open-label, randomized clinical trial conducted in 10 intensive care units in Australia, New Zealand, and Brazil that recruited 216 patients fulfilling the Sepsis-3 definition of septic shock. The first patient was enrolled on May 8, 2018, and the last on July 9, 2019. The final date of follow-up was October 6, 2019. INTERVENTIONS: Patients were randomized to the intervention group (n = 109), consisting of intravenous vitamin C (1.5 g every 6 hours), hydrocortisone (50 mg every 6 hours), and thiamine (200 mg every 12 hours), or to the control group (n = 107), consisting of intravenous hydrocortisone (50 mg every 6 hours) alone until shock resolution or up to 10 days. MAIN OUTCOMES AND MEASURES: The primary trial outcome was duration of time alive and free of vasopressor administration up to day 7. Ten secondary outcomes were prespecified, including 90-day mortality. RESULTS: Among 216 patients who were randomized, 211 provided consent and completed the primary outcome measurement (mean age, 61.7 years [SD, 15.0]; 133 men [63%]). Time alive and vasopressor free up to day 7 was 122.1 hours (interquartile range [IQR], 76.3-145.4 hours) in the intervention group and 124.6 hours (IQR, 82.1-147.0 hours) in the control group; the median of all paired differences was -0.6 hours (95% CI, -8.3 to 7.2 hours; P = .83). Of 10 prespecified secondary outcomes, 9 showed no statistically significant difference. Ninety-day mortality was 30/105 (28.6%) in the intervention group and 25/102 (24.5%) in the control group (hazard ratio, 1.18; 95% CI, 0.69-2.00). No serious adverse events were reported. CONCLUSIONS AND RELEVANCE: In patients with septic shock, treatment with intravenous vitamin C, hydrocortisone, and thiamine, compared with intravenous hydrocortisone alone, did not significantly improve the duration of time alive and free of vasopressor administration over 7 days. The finding suggests that treatment with intravenous vitamin C, hydrocortisone, and thiamine does not lead to a more rapid resolution of septic shock compared with intravenous hydrocortisone alone. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03333278.
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ItemConservative Oxygen Therapy during Mechanical Ventilation in the ICU(MASSACHUSETTS MEDICAL SOC, 2020-03-12)BACKGROUND: Patients who are undergoing mechanical ventilation in the intensive care unit (ICU) often receive a high fraction of inspired oxygen (Fio2) and have a high arterial oxygen tension. The conservative use of oxygen may reduce oxygen exposure, diminish lung and systemic oxidative injury, and thereby increase the number of ventilator-free days (days alive and free from mechanical ventilation). METHODS: We randomly assigned 1000 adult patients who were anticipated to require mechanical ventilation beyond the day after recruitment in the ICU to receive conservative or usual oxygen therapy. In the two groups, the default lower limit for oxygen saturation as measured by pulse oximetry (Spo2) was 90%. In the conservative-oxygen group, the upper limit of the Spo2 alarm was set to sound when the level reached 97%, and the Fio2 was decreased to 0.21 if the Spo2 was above the acceptable lower limit. In the usual-oxygen group, there were no specific measures limiting the Fio2 or the Spo2. The primary outcome was the number of ventilator-free days from randomization until day 28. RESULTS: The number of ventilator-free days did not differ significantly between the conservative-oxygen group and the usual-oxygen group, with a median duration of 21.3 days (interquartile range, 0 to 26.3) and 22.1 days (interquartile range, 0 to 26.2), respectively, for an absolute difference of -0.3 days (95% confidence interval [CI], -2.1 to 1.6; P = 0.80). The conservative-oxygen group spent more time in the ICU with an Fio2 of 0.21 than the usual-oxygen group, with a median duration of 29 hours (interquartile range, 5 to 78) and 1 hour (interquartile range, 0 to 17), respectively (absolute difference, 28 hours; 95% CI, 22 to 34); the conservative-oxygen group spent less time with an Spo2 exceeding 96%, with a duration of 27 hours (interquartile range, 11 to 63.5) and 49 hours (interquartile range, 22 to 112), respectively (absolute difference, 22 hours; 95% CI, 14 to 30). At 180 days, mortality was 35.7% in the conservative-oxygen group and 34.5% in the usual-oxygen group, for an unadjusted odds ratio of 1.05 (95% CI, 0.81 to 1.37). CONCLUSIONS: In adults undergoing mechanical ventilation in the ICU, the use of conservative oxygen therapy, as compared with usual oxygen therapy, did not significantly affect the number of ventilator-free days. (Funded by the Health Research Council of New Zealand; ICU-ROX Australian and New Zealand Clinical Trials Registry number, ACTRN12615000957594.).
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ItemFull predicted energy from nutrition and the effect on mortality and infectious complications in critically ill adults: a protocol for a systematic review and meta-analysis of parallel randomised controlled trials(BMC, 2015)BACKGROUND: Whilst nutrition is vital to survival in health, the precise role of nutrition during critical illness is controversial. More specifically, the exact amount of energy that is required during critical illness to optimally influence clinical outcomes remains unknown. The aim of this systematic literature review and meta-analysis is to evaluate the clinical effects of optimising nutrition to critically ill adult patients, such that the entire predicted amount of energy that the patient requires is delivered, on mortality and other important outcomes. METHODS: A systematic literature review and meta-analysis will be conducted by searching for studies indexed in Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Cochrane Library. Searches will be restricted to English. Studies will be considered for inclusion if they are a parallel randomised controlled trial investigating a nutrition intervention in an adult critical care population, where one arm delivers 'full predicted energy from nutrition' (defined as provision of ≥80% of the predicted energy required) and the other arm delivers energy less than 80% of the predicted requirement. Two authors will independently perform title screening, full-text screening, data extraction and quality assessment for this review. The quality of individual studies will be assessed using the 'Risk of Bias' tool, and to assess the overall body of evidence, a 'Summary of Findings' table and the Grades of Recommendation, Assessment, Development and Evaluation system will be used, all recommended by the Cochrane Library. Pending the study heterogeneity that is determined, a fixed-effect meta-analysis with pre-defined subgroup analyses will be performed. DISCUSSION: Currently, it is controversial whether optimal energy delivery is beneficial for outcomes in critically ill patients. This systematic review and meta-analysis will evaluate whether delivering optimal energy to critically ill adult patients improves outcomes when compared to delivery of lesser amounts. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42015027512.
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ItemNo Preview AvailableConservative oxygen therapy for mechanically ventilated adults with suspected hypoxic ischaemic encephalopathy(SPRINGER, 2020-12)PURPOSE: Liberal use of oxygen may contribute to secondary brain injury in patients with hypoxic-ischaemic encephalopathy (HIE). However, there are limited data on the effect of different oxygen regimens on survival and neurological disability in HIE patients. METHODS: We undertook a post-hoc analysis of the 166 patients with suspected HIE enrolled in a trial comparing conservative oxygen therapy with usual oxygen therapy in 1000 mechanically ventilated ICU patients. The primary endpoint for the current analysis was death or unfavourable neurological outcome at day 180. Key secondary outcomes were day 180 mortality, and cause-specific mortality. RESULTS: Patients with HIE allocated to conservative oxygen spent less time in the ICU with an SpO2 ≥ 97% (26 h [interquartile range (IQR) 13-45 vs. 35 h [IQR 19-70], absolute difference, 9 h; 95% CI - 21.4 to 3.4). A total of 43 of 78 patients (55.1%) assigned to conservative oxygen and 49 of 72 patients (68.1%) assigned to usual oxygen died or had an unfavourable neurological outcome at day 180; odds ratio 0.58; 95% CI 0.3-1.12; P = 0.1 adjusted odds ratio 0.54; 95% CI 0.23-1.26; P = 0.15. A total of 37 of 86 patients (43%) assigned to conservative oxygen and 46 of 78 (59%) assigned to usual oxygen had died by day 180; odds ratio 0.53; 95% CI 0.28-0.98; P = 0.04; adjusted odds ratio 0.56; 95% CI 0.25-1.23; P = 0.15. Cause-specific mortality was similar by treatment group. CONCLUSIONS: Conservative oxygen therapy was not associated with a statistically significant reduction in death or unfavourable neurological outcomes at day 180. The potential for important benefit or harm from conservative oxygen therapy in HIE patients is not excluded by these data.
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ItemSupplemental parenteral nutrition in critically ill patients: a study protocol for a phase II randomised controlled trial(BMC, 2015-12-24)BACKGROUND: Nutrition is one of the fundamentals of care provided to critically ill adults. The volume of enteral nutrition received, however, is often much less than prescribed due to multiple functional and process issues. To deliver the prescribed volume and correct the energy deficit associated with enteral nutrition alone, parenteral nutrition can be used in combination (termed "supplemental parenteral nutrition"), but benefits of this method have not been firmly established. A multi-centre, randomised, clinical trial is currently underway to determine if prescribed energy requirements can be provided to critically ill patients by using a supplemental parenteral nutrition strategy in the critically ill. METHODS/DESIGN: This prospective, multi-centre, randomised, stratified, parallel-group, controlled, phase II trial aims to determine whether a supplemental parenteral nutrition strategy will reliably and safely increase energy intake when compared to usual care. The study will be conducted for 100 critically ill adults with at least one organ system failure and evidence of insufficient enteral intake from six intensive care units in Australia and New Zealand. Enrolled patients will be allocated to either a supplemental parenteral nutrition strategy for 7 days post randomisation or to usual care with enteral nutrition. The primary outcome will be the average energy amount delivered from nutrition therapy over the first 7 days of the study period. Secondary outcomes include protein delivery for 7 days post randomisation; total energy and protein delivery, antibiotic use and organ failure rates (up to 28 days); duration of ventilation, length of intensive care unit and hospital stay. At both intensive care unit and hospital discharge strength and health-related quality of life assessments will be undertaken. Study participants will be followed up for health-related quality of life, resource utilisation and survival at 90 and 180 days post randomisation (unless death occurs first). DISCUSSION: This trial aims to determine if provision of a supplemental parenteral nutrition strategy to critically ill adults will increase energy intake compared to usual care in Australia and New Zealand. Trial outcomes will guide development of a subsequent larger randomised controlled trial. TRIAL REGISTRATION: NCT01847534 (First registered 5 February 2013, last updated 14 October 2015).
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ItemConservative oxygen therapy for mechanically ventilated adults with sepsis: a post hoc analysis of data from the intensive care unit randomized trial comparing two approaches to oxygen therapy (ICU-ROX)(SPRINGER, 2020-01)PURPOSE: Sepsis is a common reason for intensive care unit (ICU) admission and mortality in ICU patients. Despite increasing interest in treatment strategies limiting oxygen exposure in ICU patients, no trials have compared conservative vs. usual oxygen in patients with sepsis. METHODS: We undertook a post hoc analysis of the 251 patients with sepsis enrolled in a trial that compared conservative oxygen therapy with usual oxygen therapy in 1000 mechanically ventilated ICU patients. The primary end point for the current analysis was 90-day mortality. Key secondary outcomes were cause-specific mortality, ICU and hospital length of stay, ventilator-free days, vasopressor-free days, and the proportion of patients receiving renal replacement therapy in the ICU. RESULTS: Patients with sepsis allocated to conservative oxygen therapy spent less time in the ICU with an SpO2 ≥ 97% (23.5 h [interquartile range (IQR) 8-70] vs. 47 h [IQR 11-93], absolute difference, 23 h; 95% CI 8-38), and more time receiving an FiO2 of 0.21 than patients allocated to usual oxygen therapy (20.5 h [IQR 1-79] vs. 0 h [IQR 0-10], absolute difference, 20 h; 95% CI 14-26). At 90-days, 47 of 130 patients (36.2%) assigned to conservative oxygen and 35 of 120 patients (29.2%) assigned to usual oxygen had died (absolute difference, 7 percentage points; 95% CI - 4.6 to 18.6% points; P = 0.24; interaction P = 0.35 for sepsis vs. non-sepsis). There were no statistically significant differences between groups for secondary outcomes but point estimates of treatment effects consistently favored usual oxygen therapy. CONCLUSIONS: Point estimates for the treatment effect of conservative oxygen therapy on 90-day mortality raise the possibility of clinically important harm with this intervention in patients with sepsis; however, our post hoc analysis was not powered to detect the effects suggested and our data do not exclude clinically important benefit or harm from conservative oxygen therapy in this patient group. CLINICAL TRIALS REGISTRY: ICU-ROX Australian and New Zealand Clinical Trials Registry number ACTRN12615000957594.
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ItemDysglycaemia in the critically ill and the interaction of chronic and acute glycaemia with mortality(SPRINGER, 2014-07)PURPOSE: Hyperglycaemia is common in the critically ill. The objectives of this study were to determine the prevalence of critical illness-associated hyperglycaemia (CIAH) and recognised and unrecognised diabetes in the critically ill as well as to evaluate the impact of premorbid glycaemia on the association between acute hyperglycaemia and mortality. METHODS: In 1,000 consecutively admitted patients we prospectively measured glycated haemoglobin (HbA1c) on admission, and blood glucose concentrations during the 48 h after admission, to the intensive care unit. Patients with blood glucose ≥7.0 mmol/l when fasting or ≥11.1 mmol/l during feeding were deemed hyperglycaemic. Patients with acute hyperglycaemia and HbA1c <6.5% (48 mmol/mol) were categorised as 'CIAH', those with known diabetes as 'recognised diabetes', and those with HbA1c ≥6.5% but no previous diagnosis of diabetes as 'unrecognised diabetes'. The remainder were classified as 'normoglycaemic'. Hospital mortality, HbA1c and acute peak glycaemia were assessed using a logistic regression model. RESULTS: Of 1,000 patients, 498 (49.8%) had CIAH, 220 (22%) had recognised diabetes, 55 (5.5%) had unrecognised diabetes and 227 (22.7%) were normoglycaemic. The risk of death increased by approximately 20% for each increase in acute glycaemia of 1 mmol/l in patients with CIAH and those with diabetes and HbA1c levels <7% (53 mmol/mol), but not in patients with diabetes and HbA1c ≥7%. This association was lost when adjusted for severity of illness. CONCLUSIONS: Critical illness-associated hyperglycaemia is the most frequent cause of hyperglycaemia in the critically ill. Peak glucose concentrations during critical illness are associated with increased mortality in patients with adequate premorbid glycaemic control, but not in patients with premorbid hyperglycaemia. Optimal glucose thresholds in the critically ill may, therefore, be affected by premorbid glycaemia.