Effective sepsis management rests on three key pillars: source control, antimicrobial therapy, and circulatory resuscitation.[15] Early and intentional identification of hemodynamic instability is crucial for improving sepsis survival rates.[10] Sepsis-induced hemodynamic alterations can lead to tissue hypoxia and organ dysfunction, such as in the kidneys (S-AKI). Monitoring hemodynamics, particularly in vital organs like the kidneys, is essential in such cases.[4–6] In this study, we enrolled 36 sepsis patients, both with and without renal impairment, to evaluate the usefulness of IVC/Ao ratio ultrasonography and Ultrasonic Cardiac Output Monitor (USCOM) as dynamic methods for assessing hemodynamic status in sepsis-associated acute kidney injury. We found that S-AKI patients exhibited differences in age, sex, weight, height, comorbidities, physical parameters, and blood laboratory results. [3, 16–18]
Developing fast and precise testing modalities for assessing hemodynamics in S-AKI is essential to ensure good outcomes. These modalities should provide hemodynamic information, especially related to vascular changes and fluid tolerance, and guide the selection of appropriate, fast treatment while preventing fluid overload.[7, 8] Ultrasonography modalities have been widely accepted as a tool for assessing volume status in both pediatric and adult populations. [19, 20] USCOM was used as a non-invasive dynamic method to assess hemodynamic disturbances by measuring blood flow using doppler ultrasonography. [9] The USCOM machine uses an algorithm to automatically calculate the patient's cardiac index [14]
Utilizing the IVC/Ao ratio in ultrasound to evaluate volume status is a relatively new technique. The sonographic evaluation of the IVC/Ao diameter ratio is a simple test that physicians can effectively perform without expertise in sonography and is considered a non-complex examination. [21, 22] The IVC/Ao ratio is calculated using the diameters of the IVC and Ao, and its value varies in each child due to factors such as age, gender, body weight, and body surface area. [23] Respiratory changes and fluid deficiency conditions strongly influence IVC diameter. [23] This study found that after the intervention, there was more significant improvement in IVC diameter in the sepsis group (0.60 ± 0.17 to 0.78 ± 0.15) compared to the S-AKI group (0.57 ± 0.11 to 0.62 ± 0.13). In contrast, the diameter of the Ao remains relatively stable in every child, even in dehydration conditions, due to the Ao's diameter having lower compliance than the IVC. This study showed that the Ao diameter before the intervention between the two groups was significantly different, with the S-AKI group having higher Ao diameter values (p = 0.034). After the intervention, the difference remained significant, with the S-AKI group having higher values (p = 0.003), proving that Ao diameter is not affected by hemodynamic conditions in patients. These reasons form the basis that the diameter of the Ao acts as an internal control in each child. [21, 22] Meanwhile, the IVC/Ao ratio before (0.58 (0.38–0.65) vs 0.66 (0.56–0.78)) and after the intervention (0.61 (0.41–0.87) vs 0.94 (0.80–1.33)) showed significant differences between the two groups (p < 0.001). The renal impairment group had a lower ratio, especially after the intervention. The results align with previous research conducted by Kusumastuti et al. and Djuraska et al., which demonstrated that the average IVC/Ao ratio before management is lower and considerably higher after management. [21, 24] The significance of comparing the S-AKI group and sepsis group's IVC/Ao ratios before and after management may assist clinicians in predicting responsiveness to management.
In this study, we compared the results of the IVC/Ao ratio measured using two-dimensional ultrasonography with those of the USCOM examination. Our findings showed that the USCOM CI before and after management had significant differences in both the S-AKI groups (1.8 [1.4–2.4] compared to 3.1 [2.5–3.6]) and sepsis group (1.9 [1.5–2.9] compared to 4.1 [3.7–5.1]). However, the gap in USCOM CI scores before and after intervention in sepsis patients compared to S-AKI group was even higher. This suggests that USCOM CI can predict therapy responsiveness. Our results conclude that additional insights into hemodynamic evaluation in sepsis patients can guide more precise patient management. Although USCOM offers benefits such as non-invasiveness, speed of measurement, and ease of use in examining cardiovascular parameters in pediatric patients, especially critically ill children who are bedridden in the PICU ward, it is only available in tertiary care facilities with limited availability. [25, 26] Therefore, other methods, including measuring the IVC/Ao ratio, may be necessary in settings with limited resources.
It is important to acknowledge the limitations of this research, such as the subject restrictions. Further research with a larger number of subjects and a variety of comorbidities should be conducted.