Ethics approval for the study was obtained from Melbourne Health Human Research Committee on 27th of June of 2018 (protocol reference 2018.200). The study has been conducted in accordance with the Declaration of Helsinki and registered with the Australian and New Zealand Clinical Trial Registry on 28th of August of 2018 (ACTRN12618001442291). Table 1 in additional file 1 shows all the items of the World Health Organization trial registration data set.
Methods are reported in accordance with the Guidance for protocols of clinical trials (SPIRIT). (46) SPIRIT check list in additional file 2.
Study setting
The trial is performed at the Royal Melbourne Hospital, a tertiary public university-affiliated teaching hospital, with 706 beds located in Victoria, Australia. Participants are recruited from the internal medicine wards, which are logistically divided in long and short stay units. Short stay has 32 beds and long stay around 68 beds. Approximately, 30% of the internal medicine patients are hospitalized due to a cardiopulmonary condition.
Eligibility criteria
Patients admitted to the internal medicine wards with a preliminary cardiopulmonary diagnosis are invited to participate in the study. Eligible participants are selected every workday morning by internal medicine physicians during their handover. After presenting the new cases, physicians are asked to identify the cardiopulmonary cases. For the purpose of the study, a cardiopulmonary diagnosis has been defined as the medical suspicion that the main health problem of the patient is related with a heart or a lung condition. Under this definition are included the following symptoms: shortness of breath, chest pain, palpitations, cough, lower limb edema; and the suspicion or confirmed diagnosis of: heart failure, acute coronary syndrome, pulmonary embolism, pneumonia, decompensated chronic pulmonary obstructive disease, asthmatic crisis, cardiogenic syncope, interstitial pulmonary disease, cardiac valve disease, pleural and pericardial effusion.
Inclusion criteria:
- Age 18 years and older
- Less than 24 hours since admission to the internal medicine ward
- Cardiopulmonary diagnosis defined by an internal medicine specialist.
Exclusion criteria
- Previous echocardiography during the last 4 weeks prior to hospital admission
- Computed tomography chest during the current hospital admission
- Requiring infectious disease isolation (contact, drops or respiratory precaution)
- Unable to consent (by themselves or a third person who is nominated/identified as their next of kin).
Intervention
The intervention is a POCUS performed by an internal medicine physician with previous experience in POCUS and the certification of iHeartScan, iLungScan and Focused Cardiac Ultrasound courses from the Educational Ultrasound Group of the University of Melbourne. (XC).
POCUS is performed with an X-Porte portable ultrasonography machine (Sonosite, Bothwell, Andover, MA, USA) using a 1-5 MHz transthoracic and 6-13 MHz linear ultrasound probes. The ultrasound is performed at the patient bedside, taking an average of 20 minutes to be completed.
Assessment of the heart and lungs is performed based on the iHeartScan and iLungScan protocols, designed and validated by the Ultrasound Education Group of the University of Melbourne.(47-49) Heart structure and function are assessed using 2D images and color flow Doppler, spectral Doppler is not included in this study to facilitate timely completion of the ultrasound and to increase its reproducibility. Heart POCUS involves four anatomical windows to record eight views (Figure 1): parasternal long axis, right ventricle inflow, parasternal short axis at the level of aortic valve, parasternal short axis at the level of papillary muscle, apical four- chamber, apical five-chamber, subcostal four-chamber, and subcostal inferior vena cava.
Title Figure 1: Ultrasonography windows assessed in heart point-of-care ultrasound (POCUS).
Legend Figure 1: Four anatomical windows are used to assess eight views of the heart. 1) At the level of the fourth intercostal space lateral to the left border of the sternum, parasternal long axis (PLAX) and right ventricle inflow are recorded. 2) Second window is technically the same than the first, from PLAX the probe is rotated in clock direction ending in the parasternal short axis (PSAX). Two views are recorded at this point, one at the level of the aortic valve and other at the level of papillary muscle or mid left ventricle. 3) Apical window is found about the fifth intercostal space between the mid clavicular line ant the anterior axillary line. In this window the views assessed are apical four-chamber and apical five-chamber. 4) Subcostal window involves two views: subcostal four-chamber view of the heart and the inferior vena cava (IVC) view where the IVC can be identified ending in the right atrium.
The following variables are assessed and reported: volume and systolic function of the left and right ventricles, left atrial filling pressure based on the interatrial septum movement, significant regurgitation or stenosis of the valves, presence or not of pericardial effusion, diameter and collapsibility of the inferior vena cava. Definitions for each variable abnormality are summarized in Table 2. A final statement about the hemodynamic condition will be written as follows: normal, hypovolemia, vasodilated, primary systolic dysfunction, primary diastolic dysfunction, systolic and diastolic dysfunction, and/or right ventricle dysfunction as described by Royse et al. (15)and summarized in Table 3.
Table 2: Variables assessed and definitions of abnormality findings in heart point-of-care ultrasound.
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Variable assessed
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Definitions
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LV volume
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LV end of diastole diameter (LVEDD)
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Normal LVEDD : 3 - 5.6 cm
LV dilated > 5.6 cm
Hypovolemia < 3 cm
|
LV systolic function
|
Overall subjective impression
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Normal – Reduced -Increased
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Difference between diameters in diastole and systole (LVEDD-LVESD) in PLAX view
|
Normal 28 -44 mm
Reduced < 28 mm
Increased >44 mm
|
Difference between areas in diastole and systole
(LVEDA-LVESA) in PSAX view
|
Normal 50-65 mm2
Reduced < 50 mm2
Increased > 65 mm2
|
RV size
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Compared to LV size
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Normal < 2/3 of LV size
|
RV end of diastole diameter
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Normal < 4 cm
Increased > 4cm
|
RV systolic function
|
Overall subjective impression
|
Normal - Decreased
|
LA size
|
LA Diameter in PLAX or A4C views
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Normal <3.5 cm
|
LA area in A4C view
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Normal < 20 cm2
Increased >20 cm2
|
LA filling pressure
|
Inter-atrium septum movement
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Normal: systolic reversal of the inter-atrium septum
High filling pressure: Fixed curvature of the inter-atrium septum to the right.
Low filling pressure: Systolic buckling of the inter-atrium septum
|
Cardiac valves
|
Leaflets appearance and thickness
Opening of the valve
Presence of reverse jet
|
Significant Aortic stenosis:
An opening <1.5 cm in PLAX or
Heavy calcification with inability to see the valve opening
|
Significant Aortic regurgitation:
A jet that runs on the wall of the LV outflow track
A jet that is wider than 25% of the diameter of LVOT
A jet that extends down to the ventricle >2.5 cm
|
Significant Mitral stenosis:
Impaired opening of the mitral valve
A hockey stick appearance of one or both of the mitral leaflets
|
Significant Mitral regurgitation:
Regurgitation jet covering more than 20% of the LA area in A4C or PLAX
A turbulent jet that runs along the wall of the atrium
Prominent flail mitral valve leaflet or rupture papillary muscle
|
Significant Tricuspid regurgitation:
Any edge-tracking jet
Any central jet longer than 5 cm2
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Pericardial effusion
|
Presence of anechoic space between parietal and visceral pericardium
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Significant pericardial effusion is defined as > 0.5 cm in any view
|
Inferior vena cava
|
Diameter of the inferior vena cava in the subcostal view during normal breathing
|
Maximum diameter in cm and percentage of collapsibility during normal inspiration are reported. Estimation of the right atrium pressure is informed as follows:
IVC < 2.1 cm collapsing more than 50% à RAP: 3 mmHg
IVC > 2.1 cm collapsing less than 50% à RAP: 15 mmHg
Values between the two above à RAP:8 mmHg
|
Table 2. A4C: apical four chambers. LA: left atrium. LV: left ventricle. LVEDA: left ventricle end of diastole area. LVEDD: left ventricle end of diastole diameter. LVESA: left ventricle end of systole area. LVESD: left ventricle end of systole diameter. PLAX: parasternal long axis. PSAX: parasternal short axis. RAP: right atrium pressure. RVEDD: right ventricle end of diastole diameter.
Table 3: Hemodynamic state definitions
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Normal
|
Hypovolemia
|
Vasodilated
|
Primary systolic failure
|
Primary diastolic failure
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Systolic & diastolic failure
|
RV failure *
|
LV volume
|
Normal
|
Decreased
|
Normal
|
Increased
|
Normal/decreased
|
Increased
|
RV increased
|
LV systolic function
|
Normal
|
Normal/Decreased
|
Increased
|
Decreased
|
Normal
|
Decreased
|
RV decreased
|
LA filling pressure
|
Normal
|
Decreased
|
Normal
|
Normal
|
Increased
|
Increased
|
Increased
|
Table 3. Hemodynamic state is defined based on left ventricle volume, left ventricle systolic function and left atrium filling pressure. LV: left ventricle. LA: left atrium. RV: right ventricle.
*RV failure can be a hemodynamic state by itself or in combination with LV failure.
The lungs are scanned by division into three anatomical zones as previously reported by Ford et al.(49) (Figure 2). The anterior zone goes from the sternum edge to the mid-axillary line posteriorly; the upper posterior zone is defined by the mid-axillary line anteriorly, the spinous processes of the thoracic spine posteriorly, and the inferior tip of the scapular inferiorly: and the lower posterior zone defined by the mid-axillary line anteriorly, the spinous process of the thoracic spine posteriorly, and the inferior rip of the scapula superiorly. Abnormal findings are recorded as: collapse, consolidation, alveolar/interstitial syndrome, pneumothorax and/or pleural effusion. Definitions are described in Table 4. Normal lung pattern is defined as the presence of normal lung sliding, reverberation artefacts from the pleural, and absence of any of the pathologies described.
Title Figure 2: Anatomical zones scanned in lung point-of-care ultrasound (POCUS).
Legend Figure 2. Illustrations of the front (left) and back (right) of the chest showing the six anatomical zones scanned. RA: right anterior. LA: left anterior. LPU: left posterior upper. LPL: left posterior lower. RPU: right posterior upper. RPL: right posterior lower.
Table 4. Definitions of ultrasound lung abnormalities
Abnormal lung patterns
|
Definition / ultrasound findings
|
Alveolar/Interstitial syndrome
|
3 or more B-lines in a single rib space.
B-lines were defined as hyperechoic, vertical artifacts arising from the pleural line and reaching the bottom of the screen without fading.
|
Collapse or atelectasis
|
Loss of lung volume, increased tissue density and hyperechoic static air bronchograms
|
Consolidation
|
Tissue-like pattern or “hepatization” with minimal volume loss and the presence of dynamic air bronchograms
|
Pneumothorax
|
Absence of lung sliding and lung pulse.
|
Pleural effusion
|
Anechoic space between the parietal and visceral pleura with movement with the respiratory cycle. Significant pleural effusion is defined as > 1 cm. An estimation of the volume of a pleural effusion in milliliters (ml) will be done multiplying by 200 the distance in centimeters (cm) in the vertical plane from the diaphragm to the inferior lung border at the junction of the collapsed lung and aerated lung.
|
Femoral and popliteal veins are assessed for intravascular thrombosis using the 2-point compression technique (12, 42) (Figure 3), in which the vein collapsibility is evaluated in two points for each lower extremity: the common femoral vein at the level of the groin and the popliteal vein in the popliteal fossa. A deep venous thrombosis is defined as inability to completely collapse the vein with the ultrasound probe. This technique has proved a sensitivity of 96.1 % and specificity of 96.6% diagnosing proximal deep venous thrombosis when it has been compared to standard vein ultrasound performed by radiologists.(12, 42)
Title Figure 3: Femoral and popliteal vein point-of-care ultrasound (POCUS).
Legend Figure 3: A) The illustration shows the two points of the lower extremities assessed for deep venous thrombosis: The common femoral vein at the groin level and popliteal vein at the popliteal fossa. B) and C) are ultrasound images showing the vein marked with yellow arrows before (B) and after (C) external compression has been applied. In this case, the vein is entirely collapsible, consistent with absence of a deep venous thrombosis.
Once the test has been performed, a structured report summarizing the main findings is written. The quality of this report is immediately assessed by a second POCUS expert reviewing the images recorded. There are three experts participating in this study as quality evaluators (CR, AR and DC), all of them with at least 10 years of experience in POCUS. The revised report is given to the treating team without any direction of management, who in turn are requested to fill out forms about their clinical assessment before and after receiving the POCUS report (Figure 4).
Title Figure 4: Steps involved in the intervention group
Legend Fig. 4: In the intervention group a point-of-care ultrasound (POCUS) of the heart, lungs, femoral and popliteal veins is performed bedside the patient. The report summarizing the main findings is assessed by a second expert in POCUS before it is given to the treating team. The treating team is requested to fill out forms about their clinical assessment and management plan before and after receiving the POCUS report. Difference between forms will be recorded as influence of POCUS.
The intervention will not be performed or will be stopped after being already started if the patient refers intolerable discomfort during the procedure or in any clinical condition that involves urgent management such as cardiorespiratory arrest, pain or respiratory distress. In these cases, if some of the variables were already assessed, a report with partial information will be given to the treating team.
The control group follows the standard care pathway, which does not include POCUS. Diagnosis and management will be based on clinical evaluation and other investigations. Ultrasound examinations are not precluded such as those performed by cardiology or radiology staffs, but POCUS of the heart, lungs or lower extremities veins are not allowed during the time that the participant remains admitted to an internal medicine ward.
There are no restrictions in medication use or further standard investigations in any of the two groups.