Proposed Protocol for the Focused Analysis of Dengue Fever by Serial Ultrasound in Paediatric Patients: The AEDES Protocol

Edwin Mauricio Cantillano Quintero¹, Jesús Domínguez-Rojas², José Daniel Almazan Monroy^1*, Linda Banegas Pineda¹, Melissa Portillo Lagos¹, Javier Ponce³

¹Instituto Hondureño de Seguridad Social: San Pedro Sula, Hospital Nacional Mario Catarino Rivas: San Pedro Sula. Pediatra Intensivista. Honduras, Peru
²Instituto Nacional de Salud del Niño. Jefe de Cuidados Intensivos Pediátricos, Lima, Perú
³Hospital G Rawson, San Juan, San Juan. Pediatra Intensivista, Argentina

*Corresponding author: Jesús Dominguez-Rojas, Pediatrics Critical Care, Instituto Nacional de Salud del Niño, Lima, Perú;
Email: [email protected]

Citation: Quintero EMC, et al. Proposed Protocol for the Focused Analysis of Dengue Fever by Serial Ultrasound in Paediatric Patients: The AEDES Protocol. J Pediatric Adv Res. 2025;4(1):1-10.

Copyright^© 2025 by Quintero EMC, et al. All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Table 1: Questions and answers by fast focused ultrasound.

The use of a convex transducer (2.5 to 5 MHz) is recommended for the application of the AEDES protocol, since it has a superior penetration capacity in deeper structures. The latter has proven to be a very useful tool for the evaluation of cavity leaks. However, the sector transducer is an equally viable alternative. For pediatric pulmonary evaluations, the linear transducer emerges as a readily applicable alternative. In both cases, the default abdominal configuration should be used. It is recommended that the ultrasound equipment be placed on the right side of the patient. This arrangement makes it easier for the operator to hold the probe (or transducer) with the right hand while manipulating the ultrasound control panel with the left hand. The patient should be placed in supine decubitus at zero degrees if tolerated. Implementation of the Trendelenburg position in the patient increases the sensitivity for detection of findings within the upper abdominal windows; however, it is not considered a mandatory requirement. In cases where the patient’s head is positioned at an angle of 30 degrees or greater, there is a tendency for fluid accumulation in the lower abdomen. It is crucial to orient the transducer marker in alignment with the visible marker on the screen. This marker is systematically placed to the patient’s right in the transverse plane and to the patient’s head in the longitudinal plane (Fig. 1).

Figure 1: Useful transducers in AEDES. A: Convex transducer, B: Linear transducer, C: Indicator or mark on a linear transducer (black arrow).

The AEDES is composed of 9 basic ultrasound windows that are shown and described below Fig. 2.

Figure 2: Illustration of protocol ultrasound sites. Window 1 and 2: site of interstitial syndrome; 3 and 4: site of pleural effusion and ascites on the right; 5: site of gallbladder wall; 6 and 7: site of pleural effusion and ascites on the left; 8: site of ascites; 9: site of pericardial effusion.

Window 1 and 2: Pulmonary Interstitial Assessment

The convex or linear probe should be placed in the anterior chest cavity, parallel to the sternum, in the hemiclavicular or parasternal line, with the probe marker oriented cranially (Fig. 3). It is recommended that the hyperechoic pleural line be visualized in the center of the tissue, consistently positioned between the two acoustic shadows of the ribs, utilizing a depth of 3 to 5 cm. The depth should then be adjusted from 8 to 12 cm to assess the presence of B-lines. This step should be performed on both hemithoraces (Fig. 4).

Figure 3: Transducer placement on anterior thorax window 1 and 2.

Figure 4: A pulmonary unit exhibiting a normal pattern of A-lines, devoid of interstitial lung fluid. B and C. The presence of B lines and pleural effusion (identified by the yellow arrow in window 1 and the blue arrow in window 2) is evident.

Window 3 and 4: Assessment of Ascites and Pleural Effusion

The Right upper Quadrant (RQ) is the most sensitive area for the detection of free abdominal fluid. Window 3 represents the initial abdominal region to be examined by AEDES.

To obtain the window, the probe is positioned with the cephalic marker in the posterior axillary line, to the right, at the thoracoabdominal transition (Fig. 5). The posterior acoustic shadow of the ribs may impede visualization of the structures. In such instances, it is necessary to rotate the transducer 15° C to 20° C counterclockwise to fit it between the ribs. Once the structures have been identified, upward and downward movements should be performed while sliding the probe in a craniocaudal direction (Z-shaped movement).

Figure 5: Depicts the optimal transducer position for window 3.

It can therefore be postulated that window 3 can be divided into three distinct regions where free abdominal fluid accumulation may occur: the Morrison’s space, the caudal border of the liver and the suprahepatic space, in that order. The presence of anechoic contents (fluids) within these spaces, as illustrated in Fig. 6, is indicative of a positive AEDES [9,10].

Figure 6: A free fluid is present within the hepatorenal space, as observed in window 3 of the protocol.

Subsequently, following the administration of ultrasound waves via the probe in a cranial direction, the supra-diaphragmatic space is accessed with the objective of detecting pleural effusion. This is window 4 of the protocol, which is used to evaluate the pleural space of the right hemithorax. The presence of anechoic contents above the diaphragm and the finding of the column sign are specific features of pleural effusion, characterizing a positive AEDES (as illustrated in Fig. 7). A recently published systematic review identified the presence of pleural effusion in approximately one-third of patients with dengue, with an increased frequency observed in more severe stages of the disease [4]. Therefore, ultrasound is an effective method for detecting pleural effusion, which can be utilized as a valuable diagnostic tool for severe dengue and risk stratification 6, 16 and 17.

Figure 7: Depicts window 4, which displays an anechoic content above the diaphragm, consistent with the presence of pleural effusion.

The source of this data is: Window 5: Assessment of the Gallbladder Wall. The gallbladder is a mobile structure and can assume a variety of positions within the upper right quadrant (CSD). In order to conduct this assessment, it is necessary to position the probe in the anterior region of the CSD, immediately inferior to the last rib, parallel to the clavicular midline, with the transducer mark oriented towards the patient’s head. The transducer should then be moved up and sideways in a gentle manner, while maintaining contact with the patient’s skin [6,11].

A number of studies have demonstrated that wall thickening is a significant indicator of disease severity in dengue cases, thus making it a crucial element in the AEDES classification system [5,6]. Typically, the gallbladder wall is a thin structure, with a thickness of less than 3 mm. Fig. 8 a gallbladder wall thickness exceeding 3 mm should be regarded as pathological. The objective of AEDES is not to perform a precise measurement of the gallbladder wall; rather, it is to estimate its thickness based on the examiner’s visual impression.

Figure 8: A: Transducer placed below the last rib at midclavicular line; B: Gallbladder in normal condition in transverse axis.

In dengue with severity criteria -and plasma extravasation- the gallbladder wall is thickened and with presence of perivesicular fluid as in Fig. 9.

Figure 9: A. Gallbladder in thickened longitudinal window, example shows 7.5 mm B. Gallbladder in thickened transverse window and perivesicular edema.

Windows 6 and 7

Evaluation of ascites and left pleural effusion. The left upper quadrant is evaluated in windows 6 and 7, it consists of four points: pleural space, subdiaphragmatic space, splenorenal space and lower pole of the left kidney. The anatomical reference of the region is the spleen, which is located more posteriorly than the liver in the posterior axillary line, adjacent or adhered to the patient’s bed, with the transducer marking in a cranial direction, performing a smooth sliding and Z movement from bottom to top and viceversa (Fig. 10).

It is important to note that there is active movement of the structures as the diaphragm moves with each breath, so it is necessary to ask for an inspiratory pause and rotate the transducer clockwise to avoid rib artifact.

Figure 10: Transducer positioning for window 6 and 7.

The determination of free fluid is observed in the subdiaphragmatic space as well as in the splenorenal space as an anechoic image, then when moving the transducer cranially, a new supradiaphragmatic anechoic image is identified, compatible with probable left pleural effusion, which is considered positive AEDES (Fig. 11) [18,19,24].

Figure 11: A. Presence of free fluid in the splenorenal space in window 6; B. Presence of anechoic area on the left diaphragm compatible with pleural effusion in window 7.

Window 8: Assessment of Free Fluid in the Pelvic Fossa

In this window we evaluate the retrovesical space, where the full bladder provides the possibility of better vision since it acts as a means of transduction so it can be assessed preferably before placing a bladder catheter.

To make a longitudinal cut, the transducer is placed with the mark towards the cephalic in the suprapubic midline, pendulum movement of the transducer towards the patient’s pelvis. Then, slide the transducer to the right and left by sounding the edges of the bladder to find free fluid (Fig. 12).

Figure 12: Transducer placement in transverse suprapubic area and rotate transducer longitudinally with the mark or signal towards cephalic.

Then rotate the transducer 90 degrees to make a transverse axis with the transverse axis with the transducer mark to the right of the patient and try to center the bladder on the screen (Fig. 13). Here we can identify the bladder, uterus (women), prostate (men) and colon with a possible finding of retrovesical anechoic structure, which makes it positive for free fluid [18,19,24].

Figure 13: A. Bladder in transverse section with presence of inferior anechoic area compatible with free fluid and ligamentous structures of female organs; B. Bladder in longitudinal section with presence of anterior anechoic area compatible with free fluid.

Window 9: Assessment of pericardial effusion and inferior vena cava. Excellent tool to detect pericardial effusion and cardiac tamponade. It is a very sensitive window and is initiated by placing the transducer on the skin in the subxiphoid space with the marker to the right with a slight rotation to the right shoulder and using the liver as an acoustic window (Fig. 14). At a depth of 15 to 20 cm, the ventricles can be visualized, if not, adjust the depth or apply a little more pressure (Fig. 15).

Figure 14: Transducer positioning in subxiphoid space in transverse form of window 9.

Figure 15: The presence of a pericardial anechoic area is positive for pericardial effusion and could be complemented with other cardiac windows of the FOCUS protocol [25-29].

Limitations to this window may include obesity, prominent subxiphoid processes or severe ascites and a full stomach.

Limitations

It is important to emphasize that AEDES does not diagnose or classify the severity spectrum of dengue patients. Likewise, its potential benefit in identifying cases with warning signs, its speed, ease of performance and cost-effectiveness should be taken into account, but whoever performs it should have a certified level of training and have reached an optimal learning curve.

Conclusion

The AEDES is a structured ultrasound protocol for the evaluation of dengue-related complications in the emergency department and emergency physicians, which may aid in knowledge of the evolution and follow-up of patients and contribute to reducing mortality.

Conflict of Interests

The authors have no conflict of interest to declare.

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