Accuracy of T2 magnetic resonance assays as point-of-care methods in the intensive care unit.

BACKGROUND: Novel molecular diagnostic methods are being evaluated in order to expedite pathogen identification in patients with bacteraemia. AIMS: To evaluate the feasibility and diagnostic accuracy of the T2 magnetic resonance (T2MR) assays - T2 Bacteria (T2B) and T2 Resistance (T2R) - as point-of-care tests in the intensive care unit compared with blood-culture-based tests. METHODS: Prospective cross-sectional study of consecutive patients with suspected bacteraemia. Diagnostic accuracy was evaluated using blood culture as the reference method. FINDINGS: In total, 208 cases were included in the study. The mean time from sampling to report was lower for the T2MR assays compared with blood-culture-based methods (P<0.001). The rate of invalid reports was 6.73% for the T2B assay and 9.9% for the T2R assay. For the T2B assay, overall positive percentage agreement (PPA) was 84.6% [95% confidence interval (CI) 71.9-93.1%], negative percentage agreement (NPA) was 64.3% (95% CI 55.4-72.6%), positive predictive value (PPV) was 48.9% (95% CI 42.5-55.3%) and negative predictive value (NPV) was 91.2% (95% CI 84.4-95.2%). Cohen's kappa coefficient was 0.402. For the T2R assay, overall PPA was 80% (95% CI 51.9-95.7%), NPA was 69.2% (95% CI 54.9-81.3%), PPV was 42.9% (95% CI 31.7-54.8%) and NPV was 92.3% (95% CI 81.1-97.1%). Cohen's kappa coefficient was 0.376. CONCLUSION: T2MR assays have high NPV for rapid exclusion of bacteraemia, and could potentially assist with antimicrobial stewardship when applied as point-of-care diagnostic tests in the intensive care unit.

Neuromuscular blockade administration is associated with altered energy expenditure in critically ill intubated patients with COVID-19.

BACKGROUND & AIMS: ESPEN guidelines advocate that energy needs of critically ill patients with COVID 19 should be assessed using indirect calorimetry, if safely available. This study described energy needs of intubated patients with COVID-19 and explores whether neuromuscular blockade administration (NMBAs) is associated with altered energy expenditure. METHODS: Resting energy expenditure (REE) and respiratory exchange rate (RER) evaluated among critically ill intubated COVID-19 patients until 28th day of intensive care unit stay (ICU-S) by indirect calorimetry. Paralysed patients were defined as those with drug induced paralysis using cicatracurium, for at least 3 days during their ICU-S. RESULTS: 34 adult COVID 19 patients (59.8% male, 35.2% obese) requiring mechanical ventilation were assessed prospectively. REE measurements suggest a gradual increase of energy needs post 3rd day of ICU-S in both patients without obesity (non ob) ((from 17.8 kcal/kgr up to 29.3 kcal/kgr actual body weight (AcBW) during 28th day of ICU-S, p = 0.011)) and patients with obesity (ob) ((from 18.1 kcal/kgr up to 30.1 kcal/kgr adjusted body weight (AjBW) during 28th day of ICU-S, p = 0.021)). NMBAs use was accompanied by a significant drop in REE, especially during first 7 days of hospitalization, both in non ob (22.9 vs 17.9 kcal/kgr AcBW, p = 0.014) and ob patients (22.5 vs 19.5 kcal/kgr ABW, p = 0.027). CONCLUSION: We identified the energy needs of COVID-19 intubated patients and highlighted a significant increase beyond the 1st week in the ICU. Administration of NMBAs should be considered, as it may impact resting energy expenditure.