Effect of Antiplatelet Therapy on Survival and Organ Support-Free Days in Critically Ill Patients With COVID-19: A Randomized Clinical Trial.

Importance: The efficacy of antiplatelet therapy in critically ill patients with COVID-19 is uncertain. Objective: To determine whether antiplatelet therapy improves outcomes for critically ill adults with COVID-19. Design, Setting, and Participants: In an ongoing adaptive platform trial (REMAP-CAP) testing multiple interventions within multiple therapeutic domains, 1557 critically ill adult patients with COVID-19 were enrolled between October 30, 2020, and June 23, 2021, from 105 sites in 8 countries and followed up for 90 days (final follow-up date: July 26, 2021). Interventions: Patients were randomized to receive either open-label aspirin (n = 565), a P2Y12 inhibitor (n = 455), or no antiplatelet therapy (control; n = 529). Interventions were continued in the hospital for a maximum of 14 days and were in addition to anticoagulation thromboprophylaxis. Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of intensive care unit-based respiratory or cardiovascular organ support) within 21 days, ranging from -1 for any death in hospital (censored at 90 days) to 22 for survivors with no organ support. There were 13 secondary outcomes, including survival to discharge and major bleeding to 14 days. The primary analysis was a bayesian cumulative logistic model. An odds ratio (OR) greater than 1 represented improved survival, more organ support-free days, or both. Efficacy was defined as greater than 99% posterior probability of an OR greater than 1. Futility was defined as greater than 95% posterior probability of an OR less than 1.2 vs control. Intervention equivalence was defined as greater than 90% probability that the OR (compared with each other) was between 1/1.2 and 1.2 for 2 noncontrol interventions. Results: The aspirin and P2Y12 inhibitor groups met the predefined criteria for equivalence at an adaptive analysis and were statistically pooled for further analysis. Enrollment was discontinued after the prespecified criterion for futility was met for the pooled antiplatelet group compared with control. Among the 1557 critically ill patients randomized, 8 patients withdrew consent and 1549 completed the trial (median age, 57 years; 521 [33.6%] female). The median for organ support-free days was 7 (IQR, -1 to 16) in both the antiplatelet and control groups (median-adjusted OR, 1.02 [95% credible interval {CrI}, 0.86-1.23]; 95.7% posterior probability of futility). The proportions of patients surviving to hospital discharge were 71.5% (723/1011) and 67.9% (354/521) in the antiplatelet and control groups, respectively (median-adjusted OR, 1.27 [95% CrI, 0.99-1.62]; adjusted absolute difference, 5% [95% CrI, -0.2% to 9.5%]; 97% posterior probability of efficacy). Among survivors, the median for organ support-free days was 14 in both groups. Major bleeding occurred in 2.1% and 0.4% of patients in the antiplatelet and control groups (adjusted OR, 2.97 [95% CrI, 1.23-8.28]; adjusted absolute risk increase, 0.8% [95% CrI, 0.1%-2.7%]; 99.4% probability of harm). Conclusions and Relevance: Among critically ill patients with COVID-19, treatment with an antiplatelet agent, compared with no antiplatelet agent, had a low likelihood of providing improvement in the number of organ support-free days within 21 days. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707.

Study protocol and statistical analysis plan for the 20% Human Albumin Solution Fluid Bolus Administration Therapy in Patients after Cardiac Surgery-ll (HAS FLAIR-II) trial.

Background: Fluid bolus therapy with 20% albumin may shorten the duration of vasopressor therapy in patients after cardiac surgery. Objective: To describe the study protocol and statistical analysis plan for the 20% Human Albumin Solution Fluid Bolus Administration Therapy in Patients after Cardiac Surgery-II (HAS FLAIR-II) trial. Design, setting, participants and intervention: HAS FLAIR-II is a phase 2b, multicentre, parallel group, openlabel, randomised controlled trial that will be conducted at six Australian intensive care units. Patients requiring fluid bolus therapy after cardiac surgery will be randomly assigned in a 1:1 ratio to the intervention of fluid bolus therapy with 20% albumin or a comparator of fluid bolus therapy with a crystalloid solution. Main outcome measures: The primary outcome measure is the cumulative duration of vasopressor therapy. Secondary outcomes include vasopressor use, service utilisation, and mortality. All analyses will be conducted on an intention-to-treat basis. Results and conclusion: The study protocol and statistical analysis plan will guide the conduct and analysis of the HAS FLAIR-II trial, such that analytical and reporting biases are minimised. Trial registration: This trial has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN No. 12620000137998).

Bolus intravenous 0.9% saline leads to interstitial permeability pulmonary edema in healthy volunteers.

PURPOSE: Bolus intravenous administration of 0.9% saline has been associated with the development of pulmonary edema, and increased mortality. An animal model has previously demonstrated that rapid intravenous administration of 0.9% saline was associated with non-hydrostatic lung injury with increased lung lavage protein. We hypothesized that this non-hydrostatic effect would also occur in human volunteers. METHODS: In a randomized, cross-over study of 14 healthy male subjects, the lung lavage protein concentration and cardiorespiratory effects of an intervention with rapid intravenous administration of 30 mL/kg of 0.9% saline were compared with sham intervention. Bronchoalveolar lavage (BAL) was performed after fluid administration. Doppler echocardiography, lung ultrasound, pulmonary function tests, and blood sampling were performed before and after each intervention. RESULTS: The BAL total protein concentration was greater after 0.9% saline administration than with sham (196.1 µg/mL (SD 87.6) versus 129.8 µg/mL (SD 55.4), respectively (p = 0.020). Plasma angiopoietin-2 concentration was also increased to 2.26 ng/mL (SD 0.87) after 0.9% saline administration compared with sham 1.53 ng/mL (SD 0.69) (p < 0.001). There were small increases in stroke volume (from 58 mL (IQR 51-74) to 66 mL (IQR 58-74), p = 0.045) and Doppler echocardiography left ventricle E/e' ratio (from 5.0 (IQR 4.5-6.0) to 5.7 (IQR 5.3-6.3), p = 0.007), but no changes to right ventricular function. CONCLUSION: Rapid intravenous administration of 0.9% saline leads to interstitial permeability pulmonary edema in healthy human volunteers. Further research is now warranted to understand these effects in critically ill patients.

A retrospective audit of cumulative ionising radiation levels in hospitalised pregnant patients.

BACKGROUND: Among hospitalised patients, diagnostic radiation is possibly used least on pregnant patients due to the fear of ionising radiation on the fetus; however, what levels are currently being prescribed. AIMS: To assess the cumulative levels of ionising radiation received by pregnant patients during a single admission to a tertiary hospital. MATERIALS AND METHODS: A retrospective audit of pregnant patients admitted to Flinders Medical Centre, South Australia, Australia, between 2013 and 2017 inclusive was performed. All procedures utilising ionising radiation were collected including conventional radiology, computed tomography, fluoroscopy and nuclear medicine. Individual and cumulative effective doses for mother and fetus were calculated using patient dose reports and published conversion factors. RESULTS: From 547 patients, the median cumulative effective dose was 0.02 mSv and only five patients received more than 10 mSv, with 19.07 mSv the highest dose received. The median fetal cumulative effective dose was 0.01 mSv but only three fetuses received more than 10 mSv, likely due to fetal exclusion in some procedural fields of view. Stays longer than ten days were associated with significantly higher cumulative effective dose, as did those with maternal cardiovascular related admission, for both maternal and fetal exposures. CONCLUSION: These results suggest that pregnant patients are exposed to low doses of ionising radiation, in both individual procedures and cumulative doses. The detrimental risks associated with these levels of ionising radiation are not overt and so clinicians should question which risk is higher, the ionising radiation from the radiological procedures received or the lack of diagnostic information if avoided?

Understanding Restrictive Versus Liberal Fluid Therapy for Major Abdominal Surgery Trial Results: Did Liberal Fluids Associate With Increased Endothelial Injury Markers?

Liberal fluid strategies in critically ill patients are associated with harm, thought to be due to endothelial and glycocalyx injury. As the restrictive versus liberal fluid therapy for major abdominal surgery trial not only failed to report survival benefit with restrictive fluids but was associated with a higher rate of acute kidney injury, we hypothesized that factors other than endothelial and glycocalyx injury were likely to account for these findings. Consequently, we measured injury biomarkers in a cohort of the restrictive versus liberal fluid therapy for major abdominal surgery trial. DESIGN: The restrictive versus liberal fluid therapy for major abdominal surgery trial was an international, randomized, assessor-blinded trial comparing restrictive with liberal IV fluid regimens that represented traditional care in patients undergoing major abdominal surgery. SETTING AND PATIENTS: Cohort of restrictive versus liberal fluid therapy for major abdominal surgery bloods was collected at a single major site (161 patients) prior to, day 1 and day 3 after surgery. INTERVENTION: Bloods were blindly and randomly batch analyzed for plasma markers of endothelial/glycocalyx injury-angiopoietin-1, angiopoietin-2, soluble tyrosine-protein kinase-2 receptor, soluble intracellular adhesion molecule-1, syndecan, and tumor necrosis factor-α. Data were examined as restrictive versus liberal enrollment groups and high versus low (± 5,000 mL) fluid groups. Differences were examined by linear mixed modeling. MEASUREMENT AND MAIN RESULTS: There were no significant differences in any biomarkers between the restrictive (n = 75) and liberal (n = 86) groups. When examined as low (n = 81) and high (n = 79) fluid groups, plasma angiopoietin-2 (p = 0.009) and soluble intracellular adhesion molecule-1 (p = 0.01) were elevated in the high fluid group. There were no differences in other biomarkers. CONCLUSIONS: Although these results are consistent with previous findings of vascular injury following liberal fluid therapy, they suggest alternative mechanisms underlie the clinical outcomes from restrictive versus liberal fluid therapy for major abdominal surgery study. CLINICALTRIALSGOV IDENTIFIER: NCT01424150.

Acute respiratory distress syndrome phenotypes with distinct clinical outcomes in PHARLAP trial cohort.

Background: The Permissive Hypercapnia, Alveolar Recruitment and Low Airway Pressure (PHARLAP) randomised controlled trial compared an open lung ventilation strategy with control ventilation, and found that open lung ventilation did not reduce the number of ventilatorfree days (VFDs) or mortality in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Parsimonious models can identify distinct phenotypes of ARDS (hypo-inflammatory and hyperinflammatory) which are associated with different outcomes and treatment responses. Objective: To test the hypothesis that a parsimonious model would identify patients with distinctly different clinical outcomes in the PHARLAP study. Design, setting and participants: Blood and lung lavage samples were collected in a subset of PHARLAP patients who were recruited in Australian and New Zealand centres. A previously validated parsimonious model (interleukin-8, soluble tumour necrosis factor receptor-1 and bicarbonate) was used to classify patients with blood samples into hypo-inflammatory and hyperinflammatory groups. Generalised linear modelling was used to examine the interaction between inflammatory phenotype and treatment group (intervention or control). Main outcome measure: The primary outcome was number of VFDs at Day 28. Results: Data for the parsimonious model were available for 56 of 115 patients (49%). Within this subset, 38 patients (68%) and 18 patients (32%) were classified as having hypo-inflammatory and hyperinflammatory phenotypes, respectively. Patients with the hypo- inflammatory phenotype had more VFDs at Day 28 when compared with those with the hyperinflammatory phenotype (median [IQR], 19.5[11-24] versus 8[0-21];P= 0.03). Patients with the hyperinflammatory phenotype had numerically fewer VFDs when managed with an open lung strategy than when managed with control "protective" ventilation (median [IQR], 0 [0-19] versus 16 [8-22]). Conclusion: In the PHARLAP trial, ARDS patients classified as having a hyperinflammatory phenotype, with a parsimonious three-variable model, had fewer VFDs at Day 28 compared with patients classified as having a hypo-inflammatory phenotype. Future clinical studies of ventilatory strategies should consider incorporating distinct ARDS phenotypes into their trial design.

Cumulative radiation in critically ill patients: a retrospective audit of ionising radiation exposure in an intensive care unit.

OBJECTIVE: Ionising radiation is a valuable tool in modern medicine including for patients in an intensive care unit (ICU). However, clinicians are faced with a trade-off between benefit of information received from procedure versus risks associated with radiation. As a first step to understanding the risk and benefits of radiation exposure to ICU patients, we aimed to assess the cumulative levels of ionising radiation patients receive during their ICU stay. DESIGN: Retrospective audit. SETTING: A single tertiary care ICU in South Australia. PARTICIPANTS: This audit included 526 patients admitted to the ICU at Flinders Medical Centre, Adelaide, SA, for longer than 120 hours (long stay) over a 12-month period from April 2015 to April 2016. MAIN OUTCOME MEASURES: Cumulative radiation exposure to ICU patients. RESULTS: The 526 patients audited underwent 4331 procedures totalling 5688.45 mSv of ionising radiation. The most frequent procedure was chest x-ray (82%), which contributed 1.2% to cumulative effective dose (CED). Although only 3.6% of the total procedures, abdominal and pelvic computed tomography (CT) contributed the most to CED (68%). Over 50% of patients received less than 1 mSv CED during their stay in the ICU. However, 6% received > 50 mSv and 1.3% received > 100 mSv CED. Trauma patients received significantly higher CED compared with other admission diagnoses, and CED increased with length of stay. CONCLUSION: Most ICU patients received low CED during their stay, with the majority receiving less than the recommended limit for members of the public (1 mSv). These results may educate clinicians regarding radiation exposures in ICU settings, highlighting the relatively low exposures and thus low risk to the patients.

Small volume resuscitation with 20% albumin in intensive care: physiological effects : The SWIPE randomised clinical trial.

PURPOSE: We set out to assess the resuscitation fluid requirements and physiological and clinical responses of intensive care unit (ICU) patients resuscitated with 20% albumin versus 4-5% albumin. METHODS: We performed a randomised controlled trial in 321 adult patients requiring fluid resuscitation within 48 h of admission to three ICUs in Australia and the UK. RESULTS: The cumulative volume of resuscitation fluid at 48 h (primary outcome) was lower in the 20% albumin group than in the 4-5% albumin group [median difference - 600 ml, 95% confidence interval (CI) - 800 to - 400; P < 0.001]. The 20% albumin group had lower cumulative fluid balance at 48 h (mean difference - 576 ml, 95% CI - 1033 to - 119; P = 0.01). Peak albumin levels were higher but sodium and chloride levels lower in the 20% albumin group. Median (interquartile range) duration of mechanical ventilation was 12.0 h (7.6, 33.1) in the 20% albumin group and 15.3 h (7.7, 58.1) in the 4-5% albumin group (P = 0.13); the proportion of patients commenced on renal replacement therapy after randomization was 3.3% and 4.2% (P = 0.67), respectively, and the proportion discharged alive from ICU was 97.4% and 91.1% (P = 0.02). CONCLUSIONS: Resuscitation with 20% albumin decreased resuscitation fluid requirements, minimized positive early fluid balance and was not associated with any evidence of harm compared with 4-5% albumin. These findings support the safety of further exploration of resuscitation with 20% albumin in larger randomised trials. TRIAL REGISTRATION: http://www.anzctr.org.au . Identifier ACTRN12615000349549.

Fluid resuscitation associated with elevated angiopoietin-2 and length of mechanical ventilation after cardiac surgery.

BACKGROUND: Fluid restriction in patients with acute respiratory distress syndrome increases ventilator-free days while lowering plasma angiopoietin-2 (Ang-2), a marker of pulmonary endothelial injury. We hypothesised that fluid resuscitation may lead to endothelial injury after cardiac surgery and analysed Ang-2, angiopoietin-1 (Ang-1) and phospholipase A2 (PLA2) levels and the impact of fluid management on ventilation time. METHODS: Patients enrolled in a single-centre, prospectively randomised interventional study of liberal or conservative fluid resuscitation strategy had plasma Ang-2, Ang-1 and PLA2 levels measured at baseline (pre-operative), 6 and 24 hours after commencement of cardiopulmonary bypass, and analysed by linear mixed models as liberal v conservative (intention to treat) or high v low fluid group (actual treatment, ≥ 3250 mL of fluid administered), and further subclassified as EuroSCORE (European System for Cardiac Operative Risk Evaluation) II ≥ 0.9 or < 0.9. RESULTS: Over 9 months, 144 patients were randomly allocated to either liberal (n =74) or conservative (n =70) fluid. Patients in the liberal fluid arm tended to an increased Ang-2 (P =0.12) and had higher PLA2 levels (P =0.03). Based on actual fluid administered, Ang-2 levels were higher, the Ang-1/Ang-2 ratio lower, and the length of mechanical ventilation and intensive care unit (ICU) stay was longer in the high fluid group (P < 0.001). The highest levels of Ang- 2 and corresponding lowest Ang-1/Ang-2 ratio, along with longest length of mechanical ventilation and ICU stay, were found with both the liberal and high fluid groups in patients with a EuroSCORE II ≥ 0.9 (P < 0.01). CONCLUSION: Liberal fluid resuscitation after cardiac surgery was associated with both pulmonary endothelial injury and prolonged length of mechanical ventilation. CLINICAL TRIAL REGISTRATION: ACTRN12612000754842.

Concordance between point-of-care blood gas analysis and laboratory autoanalyzer in measurement of hemoglobin and electrolytes in critically ill patients.

BACKGROUND: We tested the hypothesis that the results of the same test performed on point-of-care blood gas analysis (BGA) machine and automatic analyzer (AA) machine in central laboratory have high degree of concordance in critical care patients and that the two test methods could be used interchangeably. METHODS: We analyzed 9398 matched pairs of BGA and AA results, obtained from 1765 patients. Concentration pairs of the following analytes were assessed: hemoglobin, glucose, sodium, potassium, chloride, and bicarbonate. We determined the agreement using concordance correlation coefficient (CCC) and Bland-Altman analysis. The difference in results was also assessed against the United States Clinical Laboratory Improvement Amendments (US-CLIA) 88 rules. The test results were considered to be interchangeable if they were within the US-CLIA variability criteria and would not alter the clinical management when compared to each other. RESULTS: The median time interval between sampling for BGA and AA in each result pair was 5 minutes. The CCC values ranged from 0.89(95% CI 0.89-0.90) for chloride to 0.98(95% CI 0.98-0.99) for hemoglobin. The largest bias was for hemoglobin. The limits of agreement relative to bias were largest for sodium, with 3.4% of readings outside the US-CLIA variation rule. The number of readings outside the US-CLIA acceptable variation was highest for glucose (7.1%) followed by hemoglobin (5.9%) and chloride (5.2%). CONCLUSION: We conclude that there is moderate to substantial concordance between AA and BGA machines on tests performed in critically ill patients. However, the two tests methods cannot be used interchangeably, except for potassium.

Fluid-induced lung injury-role of TRPV4 channels.

Administration of bolus intravenous fluid is associated with respiratory dysfunction and increased mortality, findings with no clear mechanistic explanation. The objective of this study was to examine whether bolus intravenous (i.v.) fluid administration results in acute lung injury in a rat model and further, to examine whether this injury is associated with transient receptor potential vallinoid (TRPV)4 channel function and endothelial inflammatory response. Healthy male Sprague-Dawley rats were administered 60 ml/kg 0.9% saline i.v. over 30 min. Manifestation of acute lung injury was assessed by lung physiology, morphology, and markers of inflammation. The role of TRPV4 channels in fluid-induced lung injury was subsequently examined by the administration of ruthenium red (RR) in this established rat model and again in TRPV4 KO mice. In endothelial cell culture, permeability and P-selectin expression were measured following TRPV4 agonist with and without antagonist; 0.9% saline resulted in an increase in lung water, lavage protein and phospholipase A2, and plasma angiopoietin-2, with worsening in arterial blood oxygen (PaO2), lung elastance, surfactant activity, and lung histological injury score. These effects were ameliorated following i.v. fluid in rats receiving RR. TRPV4 KO mice did not develop lung edema. Expression of P-selectin increased in endothelial cells following administration of a TRPV4 agonist, which was ameliorated by simultaneous addition of RR. Bolus i.v. 0.9% saline resulted in permeability pulmonary edema. Data from ruthenium red, TRPV4 KO mice, and endothelial cell culture suggest activation of TRPV4 and release of angiopoietin 2 and P-selectin as the central mechanism.

Fluid bolus therapy in emergency department patients: Indications and physiological changes.

OBJECTIVE: The aim of the present paper is to study the indications for fluid bolus therapy (FBT) and its associated physiological changes in ED patients. METHODS: Prospective observational study of FBT in a tertiary ED, we recorded indications, number, types and volumes, resuscitation goals and perceived success rates of FBT. Moreover, we studied key physiological variables before, 10 min, 1 h and 2 h after FBT. RESULTS: We studied 500 FBT episodes (750 [500-1250] mL). Median age was 59 (36-76) years and 57% were male. Shock was deemed present in 135 (27%) patients, septic shock in 80 (16%), and cardiogenic shock in 30 (6%). Overall, 0.9% saline (84%) was the most common fluid and hypotension the most common indication (70%). 'Avoidance of hospital/ICU admission' was the goal perceived to have the greatest success rate (85%). However, although mean arterial pressure (MAP) increased (P < 0.01) and heart rate (HR) decreased (P = 0.04) at 10 min (P = 0.01), both returned to baseline at 1 and 2 h. In contrast, respiratory rate (RR) increased at 1 (P < 0.01) and 2 h (P = 0.03) and temperature decreased at 1 and 2 h (both P < 0.001). In patients with shock, 1 h after FBT, there was a median 3 mmHg increase in MAP (P = 0.01) but no change in HR (P = 0.44), while RR increased (P < 0.01) and temperature decreased (P = 0.01). CONCLUSIONS: In ED, FBT is used mostly in patients without shock. However, after an immediate haemodynamic effect, FBT is associated with absent or limited physiological changes at 1 or 2 h. Even in shocked patients, the changes in MAP at 1 or 2 h after FBT are small.

A rare case of rapidly enlarging tracheal lobular capillary hemangioma presenting as difficult to ventilate acute asthma during pregnancy.

BACKGROUND: Lobular Capillary Hemangioma (LCH) is a benign tumour that is known to be hormone responsive and have a relatively high incidence during pregnancy, the most common site being the gingival surfaces. A tracheal origin for this tumour is extremely rare, with no case reported so far in this patient population, and the only reported clinical presentation of tracheal LCH in the literature is with haemoptysis. CASE PRESENTATION: We describe a case of a 23-year-old known asthmatic who presented at 32 weeks gestation with life-threatening respiratory failure resembling acute severe asthma, requiring invasive ventilation which was extremely difficult. This was subsequently found to be due to a large tracheal LCH producing a ball-valve phenomenon and predominantly expiratory airflow limitation similar to acute asthma. The endotracheal tube was advanced past the lesion under bronchoscopic guidance, and urgent Caesarean section performed due to foetal distress. The tumour was subsequently debulked and the trachea stented, facilitated by bi-femoral veno-venous extra-corporeal membrane oxygenation with relatively low dose of heparin. CONCLUSION: To our knowledge, this is the first report of a unique presentation and management of largest tracheal LCH so far occurring during pregnancy. Pulmonary and critical care physicians should be aware of this unique differential of refractory asthma, the aggressive nature of this benign tumour due to hormonal influences during pregnancy, and feasibility of using bi-femoral veno-venous extra-corporeal membrane oxygenation with low dose heparin as a rescue, given the high risk of bleeding.

Delayed and prolonged elevated serum paracetamol level after an overdose - possible causes and implications.

We report the case of a 29-year-old man who ingested about 50 g of standard-preparation paracetamol plus other medications. The serum paracetamol level remained low in the first 24 hours. It peaked 54 hours after ingestion and remained high for 5 days. An N-acetylcysteine (NAC) infusion was started at admission, but was ceased 36 hours later as the clinical and laboratory signs were reassuring. On Day 3, the patient's liver function deteriorated and a rising serum paracetamol level was noted; hence, an NAC infusion was reinitiated. Despite this, the patient developed fulminant hepatic failure. This case underlines the importance of monitoring paracetamol levels and liver function for at least 72 hours after a suspected large overdose of paracetamol before discontinuing NAC infusion.