Impact of Bedside Combined Cardiopulmonary Ultrasound on Etiological Diagnosis and Treatment of Acute Respiratory Failure in Critically Ill Patients

Abstract

Aims and objectives: To prospectively evaluate the impact of cardiopulmonary ultrasound (CPUS) on etiological diagnosis and treatment of critically ill acute respiratory failure (ARF) patients.

Design: This is a prospective observational study conducted in a general intensive care unit (ICU) of a tertiary care center in India. Patients over 18 years old with presence of one of the objective criteria of ARF. Patients either consecutively admitted for ARF to ICU or already admitted to ICU for a different reason but later developed ARF during their hospital stay. Written informed consent in local language was obtained from next of kin.

Interventions: All included patients underwent bedside CPUS including lung ultrasound (US) and transthoracic echocardiography plus targeted venous US by single investigator, blinded to clinical data. The US diagnosis of ARF etiology was shared with treating intensivist. Initial clinical diagnosis (ICD) and treatment plan (made before US) of each patient were compared with post-US clinical diagnosis and treatment plan. The changes in diagnosis and treatment up to 24 hours post-US were considered as impact of US.

Results: Mean age of 108 included patients was 45.7 ± 20.4 years (standard deviation). The ICD was correct in 67.5% (73/108) cases, whereas the combined CPUS yielded correct etiological diagnosis in 88% (95/108) cases. Among the 108 included patients, etiological diagnosis of ARF was altered after CPUS in 40 (37%) patients, which included "diagnosis changed" in 18 (17%) and "diagnosis added" in 22 (20%). Treatment plan was changed in 39 (36%) patients after CPUS, which included surgical interventions in 17 (16%), changes in medical therapy in 12 (11%), and changes in ventilation strategy in 4 (3.5%) patients.

Conclusion: This study demonstrates that use of combined US approach as an initial test in ARF, improves diagnostic accuracy for identification of underlying etiology, and frequently changes clinical diagnosis and/or treatment.

How to cite this article: Barman B, Parihar A, Kohli N, Agarwal A, Dwivedi DK, Kumari G. Impact of Bedside Combined Cardiopulmonary Ultrasound on Etiological Diagnosis and Treatment of Acute Respiratory Failure in Critically Ill Patients. Indian J Crit Care Med 2020;24(11):1062-1070.

Keywords: Acute respiratory failure; Combined ultrasound approach; Critical care; Impact assessment; Lung ultrasound; Transthoracic echocardiography.

Fig. 1

Bar diagram showing comparative diagnostic accuracy: initial clinical diagnosis and combined cardiopulmonary ultrasound (CPUS) diagnosis yielded a correct etiological diagnosis for acute respiratory failure (ARF) in 68% and 88% cases respectively as compared against the final diagnosis

Figs 2A to E

Ultrasound findings in a case of ARDS: LUS (A to C) showing multiple confluent B-lines diffusely in bilateral lungs (B profile) with associated pleural line irregularities (white arrow) and subpleural consolidations (white arrow); TTE (D and E) from the same patient showed normal LVEF and normal mitral inflow pattern (PW Doppler image)

Figs 3A to D

(A and B) Lung ultrasound (LUS) in a case of cardiogenic pulmonary edema showing multiple B-lines in bilateral anterior lung regions diffusely; (C) LUS in a case of pneumothorax showing the lung point which is a transition point between lung parenchyma (solid arrow) and pneumothorax (dashed arrow); (D) LUS in a case of pneumonia showing alveolar consolidation as subpleural hypoechoic region or tissue-like echotexture (C profile) with air bronchograms (white arrowheads)

Flowchart 1

Changes in etiological diagnosis of ARF after CPUS. Data represents n (%). “Diagnosis changed” represented cases where the ICD (made before US) was completely different from the modified diagnosis made by the treating intensivist after US test; and indicated complete change in etiological diagnosis of ARF. “Diagnosis added” represented cases where the ICD was part of modified diagnosis (made by the treating intensivist after US), but some additional finding/diagnosis had been added after ultrasound test

Flowchart 2

Changes in treatment plan after combined focused lung and heart ultrasound. Data represents n (%). “Lung protective ventilation” in ARDS represents mechanical ventilation using lower tidal volumes, lower inspiratory pressures, prone positioning and alveolar recruitment options by higher PEEP levels. ICT, intercostal chest tube; IMV, invasive mechanical ventilation; NIV, noninvasive ventilation