Prognostic Impact of Serial Imaging in Severe Acute Respiratory Distress Syndrome on the Extracorporeal Membrane Oxygenation.

BACKGROUND: The impact of serial imaging on the outcome of ICU patients has not been studied specifically in patients with high illness severity. METHODS: The authors sought a relationship between the numbers of antero-posterior supine chest X-rays (CXR), computed tomography (CT) examinations, and outcome in a cohort of 292 patients with severe COVID-19 ARDS collected over 24 months in a high-volume ECMO center with established ultrasound and echocardiographic diagnostics. Of the patients, 172 (59%) were obese or morbidly obese, and 119 (41%) were treated with ECMO. RESULTS: The median number of CXRs was eight per 14 days of the length of stay in the ICU. The CXR rate was not related to ICU survival (p = 0.37). Patients required CT scanning in 26.5% of cases, with no relationship to the outcome except for the better ICU survival of the ECMO patients without a need for a CT scan (p = 0.01). The odds ratio for survival associated with ordering a CT scan in an ECMO patient was 0.48, p = 0.01. The calculated savings for not routinely requesting a whole-body CT scan in every patient were 98.685 EUR/24 months. CONCLUSIONS: Serial imaging does not impact the survival rates of patients with severe ARDS. Extracorporeal membrane oxygenation patients who did not need CT scanning had significantly better ICU outcomes.

Interpleural location of chest drain on ultrasound excludes pneumothorax and associates with a low degree of chest drain foreshortening on the antero-posterior chest X-ray.

BACKGROUND: The role of chest drain (CD) location by bedside imaging methods in the diagnosis of pneumothorax has not been explored in a prospective study yet. METHODS: Covid-19 ARDS patients with pneumothorax were prospectively monitored with chest ultrasound (CUS) and antero-posterior X-ray (CR) performed after drainage in the safe triangle. CD foreshortening was estimated as a decrease of chest drain index (CDI = length of CD in chest taken from CR/depth of insertion on CD scale + 5 cm). The angle of inclination of the CD was measured between the horizontal line and the CD at the point where it enters pleural space on CR. RESULTS: Of the total 106 pneumothorax cases 80 patients had full lung expansion on CUS, the CD was located by CUS in 69 (86%), the CDI was 0.99 (0.88-1.06). 26 cases had a residual pneumothorax after drainage (24.5%), the CD was located by CUS in 31%, the CDI was 0.76 (0.6-0.93),p < 0.01. The risk ratio for a pneumothorax in a patient with not visible CD between the pleural layers on CUS and an associated low CDI on CR was 5.97, p˂0.0001. For the patients with a steep angle of inclination (> 50°) of the CD, the risk ratio for pneumothorax was not significant (p < 0.17). A continued air leak from the CD after drainage is related to the risk for a residual pneumothorax (RR 2.27, p = 0.003). CONCLUSION: Absence of a CD on CUS post drainage, low CDI on CR and continuous air leak significantly associate with residual occult pneumothorax which may evade diagnosis on an antero-posterior CR.

X-ray indices of chest drain malposition after insertion for drainage of pneumothorax in mechanically ventilated critically ill patients.

BACKGROUND: Chest drain (CD) migration in the pleural cavity may result in inadequate drainage of pneumothorax. The aim of this study was to assess several parameters that might help in diagnosing CD migration on chest X-ray (CXR). METHODS: Patients with a CD inserted from the safe triangle with a subsequent supine CXR and CT scan performed less than 24 hours apart were assessed for CD foreshortening, angle of inclination of the CD, and CD tortuosity. CD foreshortening was expressed as a ratio between CD length measured in coronal plane only and CD length inside the pleural cavity measured on CT. The angle of inclination of the CD was measured as the angle between the horizontal line and CD at the pleural space entry on CXR. CD tortuosity was calculated as a ratio between the distance from CD pleural space entry to the tip of the CD and the length of CD from the pleural space entry to its tip on CXR. RESULTS: Altogether 28 patients were included in the study. The median time between the CXR and CT examinations was 5.4 hours (IQR, 3.8-6.9 hours). CD foreshortening was the best clue of a misplaced CD with AUC of 0.93, 100% sensitivity and 88% specificity for a cut-off value of 82%. The angle of CD inclination was greater in patients with misplaced CD with AUC of 0.83, 75% sensitivity and 92% specificity for a cut-off of 50 degrees. The performance of CD tortuosity was poor. CONCLUSIONS: Greater foreshortening of the CD and a steep angle of inclination of the CD above the horizontal at chest entry should raise suspicion of CD migration and mandate further investigation by chest ultrasound to rule out residual pneumothorax occult on CXR.