Table 1.

Characteristic of included studies

Source	Study design (RCT /OBS)	Sample size (% male)	Examiner experience with PoCUSa	Examination protocol		Eligibility criteriab,c	Outcomes
				PoCUS protocol	Control
Baker [40]	RCT	442 (58)	Mixed	Volpicelli’s 8 view, subcostal cardiac clip (posterior lung not tested)	Medical history, physical examination, ECG, blood test, CXR, echocardiography, CT	Inc: ≥ 60 years, able to understand and sign a written consent, not requiring immediate resuscitation Exc: no data	Length of stay, mortality
Blans [46]	OBS	61d (52)	Beginner	BLUE, cardiac: standard transthoracic windows: LV/RV dilatation and function, pericardial tamponade / effusion, subcostal view: IVC	Not stated	Inc: call for MET based on Modified Early Warning Score Exc: pregnancy, requiring direct lifesaving intervention, GCS < 9 or GCS declined ≥ 2 as the primary reason for MET attendance	Mortality
Colclough [38]	RCT	40 (55)	Not specified	Cardiac (based on Preoperative Pocket Echocardiography Trial)	Not stated	Inc: National Health Service triage category 1–3 Exc: no data	Time to diagnosis, mortality
Corsini [47]	OBS	124 (61)	Beginner	Bilateral anterior, Lateral, and posterior lung ultrasound, transabdominal scanning for lung bases and subcostal for diaphragm	CXR	Inc: ≥ 23 week of gestational age, RR > 60, oxygen supplementation, respiratory support Exc: CPR	Time to diagnosis
Harel [48]	OBS	202 (61)	Not specified	no data	CXR	Inc: < 18 years, suspected pneumonia Exc: ED left before discharge, both PoCUS and CXR were made, PoCUS undertaken not by patient’s treating physician	Length of stay, re-admission rate
Laursen [39]	RCT	315 (43)	Expert	FATE protocol, modified Volpicelli’s 8 view, deep veins according to American College of Emergency Medicine’s criteria	Blood samples, blood gasses, ECG, CXR, CT, echocardiography	Inc: RR > 20, SAT < 95%, coughing, chest pain Exc: permanent mental disability, PoCUS not done within 1 h after the primary assessment	Length of stay, re-admission rate, mortality
Nakao [45]	OBS	324 (49)	Not specified	Volpicelli’s 8 view	Not stated	Inc: ≥ 50 years, suspected acute heart failure or COPD exacerbation Exc: ST-elevation myocardial infarction, known interstitial fibrosis, lobectomy or PTX	Time to treatment, length of stay
Pivetta [41]	RCT	518 (53)	Not specified	Volpicelli’s 8 view	Past medical history, history of present illness, physical examination, arterial blood gas analysis, ECG, CXR, N-terminal pro-brain natriuretic peptide	Inc: sudden onset of dyspnea or increase in the severity of chronic dyspnea in the previous 48 h Exc: mechanically ventilated at the time of first evaluation, dyspnea in context of trauma	Time to diagnosis, length of stay, mortality
Riishede [42]	RCT	211 (51)	Expert	Volpicelli’s 8 view (modified), subcostal or apical cardiac (4-chamber: pericardial effusion, LV function, RV overload)	clinical examination, blood samples, ECG, CXR, CT, echocardiography	Inc: coughing, chest pain, RR > 20, SAT < 95% Exc: PoCUS already done, inability to randomize or do PoCUS < 4 h	Appropriate treatment, re-admission rate, mortality
Seyedhosseini [43]	RCT	50 (58)	Mixed	BLUE protocol	Patients’ history, physical examination, CXR, biochemistry, CT	Inc: > 12 years, Acute Respiratory Distress Syndrome within the past 7 days Exc: dyspnea due to previously diagnosed medical condition, need CPR on arrival	Time to treatment, length of stay, mortality
Wang [44]	RCT	128 (51)	Expert	BLUE protocol, parasternal long-axis view to assess cardiac contractility and left ventricular ejection fraction, subxiphoid view to assess IVC	Bedside CXR, central venous and arterial blood gas parameters, myocardial injury marker levels, pulse index contour continuous cardiac output catheter, pulmonary artery catheter	Inc: admitted to ICU with acute pulmonary edema, dyspnea in 48 h, partial arterial oxygen pressure / fraction of inspired oxygen < 300 mmHg, bedside CXR showing ≥ 1 new sign of acute pulmonary edema according to the assessment of the attending ICU physician Exc: history of chronic cardiac dysfunction	Time to diagnosis, length of stay, mortality
Wang [51]	RCT	130 (49)	Expert	Extended FATE and BLUE-plus protocols were modified into a critical care ultrasonic examination protocol	Vital signs, medical history, physical examination, laboratory tests, CXR, CT	Inc: required emergent critical consultation for pulmonary or circulation failures from medical / surgical units, post-surgical patients Exc: refused ICU transfer, already experienced cardiac arrest, advanced cancer	Time to diagnosis, time to treatment, mortality
Zanobetti [49]	OBS	2683 (51)	Expert	LUS (longitudinal and oblique scans on anterolateral and posterior thoracic areas, according to Volpicelli), cardiac (apical 4-chamber view to evaluate left ventricular ejection fraction or presence of right ventricular dilatation, subcostal long axis to assess pericardial effusion and left ventricular ejection fraction), IVC	Vital signs, medical history, physical examination, ECG, CXR, CT, echocardiography, blood sampling or arterial blood gas	Inc: acute dyspnea of every degree Exc: traumatic origin, discharged after ED evaluation	Time to diagnosis
Zieleskiewicz [50]	OBS	165 (62)	Mixed	Cardiac (left and right ventricular function, pulmonary assessment), BLUE protocol, imaging of the deep veins when deemed necessary	Taking medical history, performance of a circulatory, respiratory and neurological assessment, vital signs, blood testing, conduction of any additional tests judged necessary by the physician	Inc: medical or surgical wards and developing respiratory and/or circulatory failure justifying placement of a call to the RRT Exc: pregnancy, cardiac arrest, technical limitations to the performance of US, lung or cardiac transplant, RRT call for a neurological failure, RRT call by the ED and impossible follow-up	Time to diagnosis, time to treatment, length of stay, appropriate treatment, mortality

BLUE Bedside Lung Ultrasound in Emergency, CPR cardiopulmonary resuscitation, Exc exclusion, FATE Focus Assessed Transthoracic Echocardiography, GCS Glasgow Coma Scale, Inc inclusion, IVC inferior vena cava (diameter), LUS lung ultrasound, LV left ventricule, MET Medical Emergency Team, OBS observational study, RCT Randomized Control Trial, RR respiratory rate/min, RRT rapid response team, RV right ventricule, SAT peripheral oxygen saturation

^aExaminer practice: beginner: trained in basic level and/or low clinical experience; expert: trained in high level and/or high level of clinical experience

^bConsent and dyspnea as an eligibility criteria is not specifically mentioned, due to being omnipresent

^cAge restriction is highlighted only when children or older population were included

^dWe received data from the authors just about patients treated with respiratory failure