Co-Administration of High-Dose Nebulized Colistin for Acinetobacter baumannii Bacteremic Ventilator-Associated Pneumonia: Impact on Outcomes

Acinetobacter baumannii (A. baumannii) is a difficult-to-treat (DTR) pathogen that causes ventilator-associated pneumonia (VAP) associated with high mortality. To improve the outcome of DTR A. Baumannii VAP, nebulized colistin (NC) was introduced with promising but conflicting results on mortality in earlier studies. Currently, NC is used at a much higher daily dose compared to the past. Nevertheless, there is little evidence on the effect of high-dose NC on the outcomes of A. baumannii VAPs, especially in the current era where the percentage of colistin-resistant A. baumannii strains is rising. We conducted a retrospective study comparing bacteremic A. baumannii VAP patients who were treated with and without NC co-administration and were admitted in the Intensive Care Unit of University Hospital of Ioannina from March 2020 to August 2023. Overall, 59 patients (21 and 38 with and without NC coadministration, respectively) were included. Both 28-day and 7-day mortalities were significantly lower in the patient group treated with NC (52.4% vs. 78.9%, p 0.034 and 9.5% vs. 47.4%, p 0.003, respectively). Patients treated with NC had a higher percentage of sepsis resolution by day 7 (38.1% vs. 13.5%, p 0.023) and were more likely to be off vasopressors by day 7 (28.6% vs. 8.1%, p 0.039). The addition of NC in the treatment regime of A. baumannii VAP decreased mortality.

A combination of mild-moderate hypoxemia and low compliance is highly prevalent in persistent ARDS: a retrospective study

BACKGROUND

The Acute Respiratory Distress Syndrome (ARDS) is characterized by lung inflammation and edema, impairing both oxygenation and lung compliance. Recent studies reported a dissociation between oxygenation and compliance (severe hypoxemia with preserved compliance) in early ARDS and COVID-19-related-ARDS (CARDS). During the pandemic, in patients requiring prolonged mechanical ventilation, we observed the opposite combination (mild-moderate hypoxemia but significantly impaired compliance). The purpose of our study was to investigate the prevalence of this combination of mild-moderate hypoxemia and impaired compliance in persistent ARDS and CARDS.

METHODS

For this retrospective study, we used individual patient-level data from two independent cohorts of ARDS patients. The ARDSNet cohort included patients from four ARDS Network randomized controlled trials. The CARDS cohort included patients with ARDS due to COVID-19 hospitalized in two intensive care units in Greece. We used a threshold of 150 for PaO2/FiO2 and 30 ml/cmH2O for compliance, estimated the prevalence of each of the four combinations of oxygenation and compliance at baseline, and examined the change in its prevalence from baseline to day 21 in the ARDSNet and CARDS cohorts.

RESULTS

The ARDSNet cohort included 2909 patients and the CARDS cohort included 349 patients. The prevalence of the combination of mild-moderate hypoxemia and low compliance increased from baseline to day 21 both in the ARDSNet cohort (from 22.2 to 42.7%) and in the CARDS cohort (from 3.1 to 33.3%). Among surviving patients with low compliance, oxygenation improved over time. The 60-day mortality rate was higher for patients who had mild-moderate hypoxemia and low compliance on day 21 (28% and 56% in ARDSNet and CARDS), compared to those who had mild-moderate hypoxemia and high compliance (20% and 50%, respectively).

CONCLUSIONS

Among patients with ARDS who require prolonged controlled mechanical ventilation, regardless of ARDS etiology, a dissociation between oxygenation and compliance characterized by mild-moderate hypoxemia but low compliance becomes increasingly prevalent. The findings of this study highlight the importance of monitoring mechanics in patients with persistent ARDS.

P1767 Abnormal longitudinal peak systolic strain in asymptomatic patients with psoriatic arthritis

Purpose

Purpose of this study is to evaluate systolic and diastolic myocardial function in asymptomatic patients with PsA and no cardiac comorbidities and to reveal the value of speckle tracking echocardiography in this object.

Methods

Sixty patients (29 males, mean age 52.55) and 34 healthy controls (18 males, mean age 50.79) participated the study. They were subjected to TTE to evaluate left ventricular systolic function with conventional indexes such as ejection fraction (EF) and with novel indexes such as global longitudinal strain (GLS); diastolic dysfunction was also assessed in both groups. Blood exams were conducted including crp, esr. Severity scales of the disease such as PASI and DAS 28 scores, and the duration of the disease were also recorded.

Results

Linear regression analysis showed significantly impaired global longitudinal peak systolic strain (GLS) in PsA patients (mean =-19.79, s.d. =4.54) compared to the controls (mean =-23.67, s.d. =3.27). Ejection fraction, on the contrary, did not show any significant difference between the two groups. Left ventricular diastolic function did not present significant difference between the two groups. Comparison of GLS with PASI and DAS 28 scores, disease duration, esr and crp showed no association.

Conclusions

PsA patients present a higher risk of left ventricular systolic dysfunction. GLS is a useful tool in revealing myocardial impairment. Moreover, this high risk for systolic dysfunction did not appear to correlate with disease severity markers.

Systolic and diastolic function indexes GroupStatistics group N Mean Std. Deviation Std. ErrorMean p-value E/A Cases 60 1,1510 ,49319 ,06367 0,971 Controls 34 1,1471 ,53555 ,09185 E/E" (average) Cases 60 8,21 3,016 ,389 0,703 Controls 32 7,95 3,096 ,547 GLS (%) Cases 52 -19,795 4,5495 ,6309 <0,001 Controls 34 -23,671 3,2668 ,5602 EF(%) Cases 59 59,24 3,919 ,510 0,986 Controls 34 59,26 10,880 1,866 Differences between PsA patients and control group

Abstract P1767 Figure. GLS in PsA patients and control group