Bowel sonography in sepsis with pathological correlation: an experimental study

Abdominal perfusion in canine patients with pyometra and sepsis evaluated by Doppler and contrast-enhanced ultrasound

BACKGROUND

Sepsis is a condition characterized by organic dysfunction, leading to hemodynamic instability and high morbidity and mortality rates in humans and animals. Early identification of perfusion changes and appropriate management of sepsis are crucial for improving patient prognosis. Currently, the Systemic Inflammatory Response Syndrome (SIRS) and Sequential Organ Failure Assessment (SOFA) scores are widely studied for sepsis identification and evaluation of organ dysfunction. However, these scores do not assess gastrointestinal involvement, which is common in this condition. Contrast-enhanced ultrasound (CEUS) and Doppler have been considered promising diagnostic techniques for detecting changes in vascularization and microcirculation in a non-invasive and safe manner, particularly in the gastrointestinal system. This study aimed to evaluate duodenal perfusion using CEUS, as well as abdominal aortic and cranial mesenteric artery blood flow using Doppler ultrasound, and systolic arterial pressure (SAP) in 17 bitches with pyometra and in 10 healthy animals.

RESULTS

The variables were compared between the pyometra and control groups, as well between patients with and without sepsis determined by the SOFA or SIRS scores. Pyometra was found to cause a reduction in abdominal aortic blood flow volume, aortic peak systolic velocity, and resistivity index as evaluated by Doppler ultrasound. Patients with sepsis according to the SOFA criteria only presented lower SAP. In contrast, sepsis animals identified by the SIRS score exhibited lower SAP, aortic peak systolic velocity, aortic blood flow volume, and aortic resistivity index and additionally, higher peak intensity of contrast in the duodenal wall.

CONCLUSIONS

Pyometra causes a reduction in abdominal aortic blood flow, which is more pronounced in animals with sepsis identified by the SIRS criteria. These animals also exhibited a decrease in systolic blood pressure and an increase in duodenal perfusion, as evident by CEUS. However, these changes were not observed in patients with sepsis identified by the SOFA criteria. The alterations in intestinal perfusion observed in animals with sepsis indicate the presence of inflammation or dysfunction. In this regard, CEUS proves to be a valuable technique for detecting subtle changes in tissue hemodynamics that may not be apparent in conventional exams.

Measuring gut perfusion and blood flow in neonates using ultrasound Doppler of the superior mesenteric artery: a narrative review

The gut is a relatively silent organ in utero but takes on a major role after birth for the absorption and digestion of feed for adequate nutrition and growth. The neonatal circulation undergoes a transition period after birth, and gut perfusion increases rapidly to satisfy the oxygen demand and consumption. If this process is compromised at any stage, preterm and fetal growth restricted infants are at particular risk of gut tissue injury secondary to hypoxia, leading to necrotizing enterocolitis. Feeding can also be a challenge in these high-risk groups due to gut dysmotility. Superior mesenteric artery (SMA) Doppler is a safe, bedside investigation that could rapidly aid clinicians with feeding strategies and in monitoring high-risk infants. This article aims to establish normal patterns of gut blood flow velocity in neonates using SMA Doppler and reviews how it might be used clinically in pathologic states.

Emerging prediction methods for early diagnosis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a life-threatening disease of the digestive system that occurs in the neonatal period. NEC is difficult to diagnose early and the prognosis is poor. Previous studies have reported that abnormalities can be detected before the presentation of clinical symptoms. Based on an analysis of literature related to the early prediction of NEC, we provide a detailed review on the early prediction and diagnosis methods of NEC, including ultrasound, near-infrared spectroscopy, biomarkers, and intestinal microbiota. This review aimed to provide a reference for further research and clinical practice.

Risk factors for the prognosis of patients with sepsis in intensive care units

Background and purpose

To date, sepsis remains the main cause of mortality in intensive care units (ICU). This study aimed analyze the risk factors of the prognosis in sepsis patients.

Methods

In this case-control study, patients with sepsis admitted to the intensive care unit of a Chinese hospital between January and November 2020 were analyzed. Ultrasound and clinical data were analyzed and compared between non-survivors and survivors. The ROC curve analysis was also performed to determine the best indicator for predicting mortality.

Results

A total of 72 patients with sepsis in ICU were included for analysis. The basic characteristics between the survivals and non-survivals were similar, except for acute physiology and chronic health evaluation (APACHE) Ⅱ score, sepsis-related organ failure assessment (SOFA) score, lactate level, ultrasound parameters from superior mesenteric artery (SMA) such as peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistive index (RI). Univariate analysis revealed that the APACHE Ⅱ score, SOFA score, lactate, low PSV, EDV, and RI were potential risk factors for mortality in sepsis, while multivariate analysis suggested that low PSV was an independent risk factor for mortality, and the adjusted odds ratio was 0.295 (95% CI: 0.094–0.925). The ROC analysis showed that the PSV (AUC = 0.99; sensitivity and specificity were 0.99 and 0.96, respectively) had good predictive value for mortality in sepsis.

Conclusion

Low PSV as found to be an independent risk factor and good predictor for mortality in patients with sepsis. This study shows the promise of ultrasound in predicting mortality in patients with sepsis; however, further studies are needed to validate these results.

Animal models of necrotizing enterocolitis

Background

Necrotizing enterocolitis (NEC) is one of the leading causes of death in premature infants. To determine the factors present in the disease that lead to increased morbidity and mortality, manipulation of variables that are shown to have a positive response has been tested using various animal models. Testing and manipulation of these variables are unwarranted in humans due to regulatory health standards.

Methods

The purpose of this review is to provide an update to previous summaries that determine the significance of animal models in studying the mechanisms of NEC. A large variety of animal models including rats, mice, rabbits, piglets, nonhuman primates, and quails have been described in literature. We reviewed the reported animal models of NEC and examined the pros and cons of the various models as well as the scientific question addressed.

Results

The animals used in these experiments were subject to gavage feeding, hypoxia, hypothermia, oxygen perfusion, and other methods to induce the disease state. Each of these models has been utilized to show the effects of NEC on the premature, undeveloped gut in animals to find a correlation to the disease state present in humans. We found specific advantages and disadvantages for each model.

Conclusions

Recent advances in our understanding of NEC and the ongoing therapeutic strategy developments underscore the importance of animal models for this disease.

Targeting IL-17A Improves the Dysmotility of the Small Intestine and Alleviates the Injury of the Interstitial Cells of Cajal during Sepsis

Intestinal dysmotility is a frequent complication during sepsis and plays an important role in the development of secondary infections and multiple organ failure. However, the central mechanisms underlying this process have not been well elucidated. Currently, effective therapies are still lacking for the treatment of sepsis-induced intestinal dysmotility. In this study, we found that the activation of IL-17 signaling within the muscularis propria might be associated with dysmotility of the small intestine during polymicrobial sepsis. Furthermore, we demonstrated that targeting IL-17A partially rescued the motility of the small intestine and alleviated interstitial cells of Cajal (ICC) injury during sepsis. The blockade of IL-17A suppressed the dominant sepsis-induced infiltration of M1-polarized macrophages into the muscularis. Additionally, impaired ICC survival may be associated with the oxidative stress injury induced by dominant infiltration of M1-polarized macrophages. Our findings reveal the important role of the IL-17 signaling pathway in the small intestine during sepsis and provide clues for developing a novel therapeutic strategy for treating gastrointestinal dysmotility during sepsis.

Doppler ultrasound assessment of the splanchnic circulation in preterms with neonatal sepsis at risk for necrotizing enterocolitis

OBJECTIVE

To evaluate the role of Doppler ultrasonography in the assessment of splanchnic circulation's hemodynamic changes in septic preterms at risk of necrotizing enterocolitis.

METHODS

A total of 51 septic preterms were divided into two groups: 25 preterms with clinical signs of necrotizing enterocolitis (NEC) and 26 preterms with no clinical signs of NEC. Both groups were assessed with Doppler ultrasonography of the celiac and superior mesenteric arteries, and each septic preterm's peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), and pulsatility index (PI) was calculated and recorded.

RESULTS

These included a statistically significant lower PSV (p: 0.001) and a lower EDV (p: 0.001) in the superior mesenteric artery in the septic group with clinical signs of NEC in comparison with the septic group with no clinical signs of NEC. A statistically significant (p < 0.001) higher PSV celiac (CA)/PSV superior mesenteric (SMA) ratio was found for the group of septic preterms with clinical signs of NEC when compared to the other group.

CONCLUSION

The study results showed that Doppler ultrasonography of the splanchnic circulation can be a tool for the early identification of NEC cases among septic preterms.

Relationship Between Near-Infrared Spectroscopy and Transabdominal Ultrasonography: Noninvasive Monitoring of Intestinal Function in Neonates

BACKGROUND

Near-infrared spectroscopy (NIRS) has the potential to continuously and noninvasively monitor intestinal function. This technology may be valuable because among neonates, intestinal maturity is highly variable and difficult to assess based solely on clinical signs. The aim of this study was to determine if there is an association between NIRS-based StO2 measurements and peristaltic activity assessed by transabdominal ultrasonography (US).

MATERIAL/METHODS

Nineteen neonates of gestational age >32 weeks were categorized according to "no/low" versus "normal/hyperactive" motility levels, based on blinded US scan results. StO2 was recorded every 2 s for 24 h, following the ultrasound recording. Differences between the resulting estimates of average StO2 (bias of fits) and goodness-of-fit (residuals) were evaluated.

RESULTS

Newborns with normal/hyperactive motility had higher mean StO2 than newborns with no/low motility (72.3±4.4 vs. 65.5±7.9, p<0.05, F=5.65). Residual errors were not significantly different between the 2 groups (p=0.213, F=0.213). A multivariate linear regression model using the means, residuals, and pairwise products of both, demonstrated more significant separation (0.47±0.26 vs. -0.24±0.33, p<0.01, F=27.4). A non-linear variant of the multivariate linear regression model demonstrated greatest separation (0.68±0.24 vs. -0.49±0.53, p<0.01, F=41.9).

CONCLUSIONS

This is the first study to demonstrate an association between NIRS-based StO2 measurements and peristaltic activity visualized by ultrasound imaging. NIRS may offer a continuous, noninvasive method to assess motility. This may have significant implications in premature infants at risk for feeding intolerance or necrotizing enterocolitis.

Complementory Value of Sonography in Early Evaluation of Necrotizing Enterocolitis

Background

Despite the widespread use of plain films to detect necrotizing enterocolitis (NEC), it is considered a time-consuming method, which exposes patients to radiation. We aimed to assess changes in ultrasonographic variables and to compare sonograhy and chest radiography in detecting early stages of NEC in suspected premature infants.

Material/Methods

This case-control study was carried out in the years 2012–2013. We enrolled 67 premature neonates using a simple sampling method and divided them into the study and control groups. All patients underwent plain abdominal radiography, gray-scale and color Doppler sonography.

Results

34 and 33 neonates were assigned to the study and control groups. No significant gender differences were found between the two groups (P=0.549). The mean bowel wall thickness ranged from 1.2 to 3.2 mm in the control group (132 abdominal quadrants) and 1–3.3 mm in the study group (136 abdominal quadrants, P=0.502). Intra-mural echogenic dots were seen in one neonate in the study group in favour of pneumatosis intestinalis. The mean ±SD bowel wall perfusion in the study and control groups were 3.117±0.975 and 2.878±0.538 dots or lines/cm², respectively (P=0.218). One neonate in the study group showed internal echoes within the mild amount of free fluid. Twelve neonates in the control group had minimal amounts of intra-abdominal free fluid.

Conclusions

The two groups differed regarding bowel wall thickness, echogenicity, and perfusion in sonograhy and color Doppler evaluation. Although those differences were not statistically significant, considering the time-consuming nature of abdominal X-ray, the use of sonograhy and color Doppler can improve diagnosis and treatment of NEC as a triage method.

Prognostic value of abdominal sonography in necrotizing enterocolitis of premature infants born before 33 weeks gestational age

OBJECTIVE

The purpose of this study was to assess the prognostic value of abdominal sonography in necrotizing enterocolitis (NEC) in preterm infants with a gestational age less than 33 weeks of gestation, using surgery and/or death as the primary outcome and stenosis as the secondary outcome.

METHODS

A retrospective study of 95 premature infants (mean gestational age: 28.6 weeks), presenting with NEC between January 2009 and November 2011 and who underwent plain abdominal radiography and sonography, was performed. In uni- and multivariate analyses, radiographic and sonographic findings were correlated with complications ('surgery and/or death' and 'stenosis').

RESULTS

Sonographic findings of free intraperitoneal air (odd ratio [OR]=8.0; IC, 1.4-44.2), free abdominal fluid (OR 3.5; IC 1.3-9.4), portal venous gas (OR 3.9; IC, 1.2-12.9), and bowel wall thickening (OR 2.8; IC,1.1-7.2) were significantly associated with surgery and/or death. Intramural gas was significantly correlated (OR=11.8; IC, 1.5-95.8) with intestinal stenosis following NEC. None of the radiographic findings were associated with complications.

CONCLUSION

Abdominal sonography is a reliable tool for the prognostic assessment of NEC in preterm infants.