Role of point-of-care ultrasound in critical care and emergency medicine: update and future perspective

Point-of-care ultrasound (POCUS) is a rapidly developing technology that has the potential to revolutionize emergency and critical care medicine. The use of POCUS can improve patient care by providing real-time clinical information. However, appropriate usage and proper training are crucial to ensure patient safety and reliability. This article discusses the various applications of POCUS in emergency and critical care medicine, the importance of training and education, and the future of POCUS in medicine.

Expert opinion on evidence after the 2020 Korean Cardiopulmonary Resuscitation Guidelines: a secondary publication

Considerable evidence has been published since the 2020 Korean Cardiopulmonary Resuscitation Guidelines were reported. The International Liaison Committee on Resuscitation (ILCOR) also publishes the Consensus on CPR and Emergency Cardiovascular Care Science with Treatment Recommendations (CoSTR) summary annually. This review provides expert opinions by reviewing the recent evidence on CPR and ILCOR treatment recommendations. The authors reviewed the CoSTR summary published by ILCOR in 2021 and 2022. PICO (patient, intervention, comparison, outcome) questions for each topic were reviewed using a systemic or scoping review methodology. Two experts were appointed for each question and reviewed the topic independently. Topics suggested by the reviewers for revision or additional description of the guidelines were discussed at a consensus conference. Forty-three questions were reviewed, including 15 on basic life support, seven on advanced life support, two on pediatric life support, 11 on neonatal life support, six on education and teams, one on first aid, and one related to COVID-19. Finally, the current Korean CPR Guideline was maintained for 28 questions, and expert opinions were suggested for 15 questions.

Application of point-of-care ultrasound for different types of esophageal foreign bodies: three case reports: A CARE-compliant article

RATIONALE

Esophageal point-of-care ultrasound (POCUS) has recently been reported as a useful, quick, safe, and simple technique to detect esophageal foreign bodies (FBs). However, case series to detect esophageal FB using POCUS have been rarely reported. Chicken bones and pills, especially, have not yet been reported as esophageal FBs. The objective of this case series was to describe the POCUS findings of 3 different materials-food, pill, and chicken bone.

PATIENT CONCERNS

Case 1, a 75-year-old woman with odynophagia and neck pain occurring 30 min after eating chicken porridge; Case 2, a 32-year-old woman with neck discomfort occurring 2 h after taking a pill; Case 3, a 29-year-old woman reporting FB sensation in the neck that occurred 1 h after eating sausage and rice soup.

DIAGNOSIS

Case 1. Cervical esophageal FB (chicken bone), Case 2. Cervical esophageal FB (oral pill), Case 3. Cervical esophageal FB (food).

INTERVENTIONS

Case 1. POCUS, urgent esophagogastroduodenoscopy (EGD) with alligator forceps. POCUS findings; hyperechoic material (suspected FB) that did not disappear by swallowing and esophageal dilatation with pooling of secretions. Case 2. POCUS. POCUS findings; hypoechoic material (suspected FB) that did not disappear by swallowing, and esophageal bulging above the FB, especially observed in the longitudinal view. Case 3. POCUS. POCUS findings; hyperechoic material (suspected FB) with reverberation artifact that did not disappear with swallowing efforts. Prior FB esophageal bulging with persistent air-fluid level was especially observed in the longitudinal view.

OUTCOMES

Case 1. FB was removed by EGD with alligator forceps. Case 2. Symptoms disappeared under observation without EGD. Follow-up POCUS revealed normalized bulging esophagus. Case 3. These symptoms improved after vomiting a large piece of food material. Three patients were discharged without complications.

LESSONS

In this case series, the impacted materials were chicken bone, pill, and food. However, POCUS findings were similar (esophageal dilation, hyperechoic or hypoechoic lesion with mixed echogenic contents in food or secretion, and no change with swallowing efforts). A longitudinal view was useful to assume the presence of cervical esophageal FB in all three cases. Thus, POCUS findings could be indirect signs of a FB in the esophagus.

Interrater reliability of emergency physician-performed ultrasonography for diagnosing femoral, popliteal, and great saphenous vein thromboses compared to the criterion standard study by radiology

PURPOSE

To assess the interrater reliability and test characteristics of lower limb sonographic examination for the diagnosis of deep venous and proximal great saphenous vein thrombosis when performed by Emergency Physicians (EPs) as compared to that by the Department of Radiology (Radiology). The secondary objective was to assess the effects of patient body mass index and EP satisfaction with bedside ultrasound on sensitivity and specificity.

METHODS

A prospective study was conducted for patients with clinical suspicion for lower extremity thrombus. EPs evaluated for venous thrombosis in the common femoral vein, femoral vein of the thigh, popliteal vein, and proximal great saphenous vein. Subsequently, all patients received ultrasounds by Radiology, the criterion standard.

RESULTS

One hundred ninety-seven patients (257 individual legs) were evaluated. There was 90-95% agreement between EP and Radiology, moderate kappa agreement for common femoral vein, and femoral vein of the thigh and fair kappa agreement for great saphenous vein and popliteal vein. The sensitivity and specificity of EP ultrasounds compared with criterion standard were lower than previously reported. There was no trend in patient body mass index or provider satisfaction influencing the test characteristics.

CONCLUSIONS

Our study suggests that point-of-care sonography should not replace Radiology-performed scans. The required amount of training for EPs to be competent in this examination needs further investigation. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:360-367, 2016.

Ischemia-induced changes in glucagon-like peptide-1 receptor and neuroprotective effect of its agonist, exendin-4, in experimental transient cerebral ischemia

Glucagon-like peptide-1 receptor (GLP-1R) protects against neuronal damages in the brain. In the present study, ischemia-induced changes in GLP-1R immunoreactivity in the gerbil hippocampal CA1 region were evaluated after transient cerebral ischemia; in addition, the neuroprotective effect of the GLP-1R agonist exendin-4 (EX-4) against ischemic damage was studied. GLP-1R immunoreactivity and its protein levels in the ischemic CA1 region were highest at 1 day after ischemia/reperfusion (I/R). At 4 days after I/R, GLP-1R immunoreactivity was hardly detected in CA1 pyramidal neurons, and its protein level was lowest. GLP-1R protein level was increased again at 10 days after I/R, and GLP-1R immunoreactivity was found in astrocytes and GABAergic interneurons. In addition, EX-4 treatment attenuated ischemia-induced hyperactivity, neuronal damage, and microglial activation in the ischemic CA1 region in a dose-dependent manner. EX-4 treatment also induced the elevation of GLP-1R immunoreactivity and protein levels in the ischemic CA1 region. These results indicate that GLP-1R is altered in the ischemic region after an ischemic insult and that EX-4 protects against ischemia-induced neuronal death possibly by increasing GLP-1R expression and attenuating microglial activation against transient cerebral ischemic damage.

Long-term changes in neuronal degeneration and microglial activation in the hippocampal CA1 region after experimental transient cerebral ischemic damage

Delayed neuronal death following transient cerebral ischemia is mixed with apoptosis and necrosis, and the activation of microglia are activated after the ischemic insult. In the present study, we examined the long-term changes in neuronal degeneration and microglial activation in the gerbil hippocampal CA1 region after 5min of transient cerebral ischemia using specific markers for neuronal damage and microliosis. Transient ischemia-induced neuronal death was shown in CA1 pyramidal cells 4days after ischemia/reperfusion (I/R). However, neuronal degeneration of the pyramidal cells were observed up to 45days in the CA1 region after I/R. Microglial activation was also observed in the CA1 region after I/R. Isolectin B4- (IB4) immunoreactive ((+)) microglia appeared in the CA1 region 4days after I/R. On the other hand, ionized calcium-binding adapter molecule 1 (Iba-1)(+) microglia was markedly increased after I/R, and peaked at 15days after I/R. Thereafter, Iba-1 immunoreactivity was decreased with time-dependant manner in the ischemic CA1 region. These results indicate that neuronal degeneration of CA1 pyramidal cells may last about 45days in the CA1 region after ischemic damage, and microglial activation may be diverse according to their function, such as phagocytosis, after I/R.

Rosiglitazone, an agonist of peroxisome proliferator-activated receptor gamma, decreases immunoreactivity of markers for cell proliferation and neuronal differentiation in the mouse hippocampus

In the present study, we investigated the regulating effects of rosiglitazone (RSG), a synthetic agonist of peroxisome proliferator-activated receptor gamma, treatment for 28days on the cell proliferation and neuronal differentiation in the mouse hippocampal dentate gyrus by 5-bromo-2'-deoxyuridine (BrdU), Ki67 and doublecortin (DCX) immunohistochemistry. These markers were detected in the subgranular zone (SGZ) of the dentate gyrus in vehicle- and RSG-treated groups. In the RSG-treated group, the number of BrdU-, Ki67- and DCX-immunoreactive cells was significantly decreased compared to those in the vehicle-treated group. In addition, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor levels were significantly decreased in the dentate gyrus of the RSG-treated groups compared to the vehicle-treated group. These results indicate that RSG treatment decreases immunoreactivities of markers for cell proliferation and neuronal differentiation and levels of neurotrophic factors in the SGZ of the hippocampal dentate gyrus.

Characterization of multicomponent monosaccharide solutions using an enzyme-based sensor array

We report the development of a sensor for rapidly and simultaneously measuring multiple sugars in aqueous samples. In this strategy, enzyme-based assays are localized within an array of individually addressable sites on a micromachined silicon chip. Microspheres derivatized with monosaccharide-specific dehydrogenases are distributed to pyramidal cavities anisotropically etched in a wafer of silicon (100) and are exposed to sample solution that is forced through the cavities by a liquid chromatography pumping system. Production of fluorescent reporter molecules is monitored under stopped-flow conditions when localized dehydrogenase enzyme systems are exposed to their target sugars. We demonstrate the capability of this analysis strategy to quantify beta-D-glucose and beta-D-galactose at low micromolar to millimolar levels, with no detectable cross-talk between assay sites. Analysis is achieved either through fluorescence detection of an initial dehydrogenase product (NADH, NADPH) or by production of a secondary fluorescent product created by hydride transfer from the reduced nicotinamide cofactor to a fluorogenic reagent. The array format of this sensor provides capabilities for redundant analysis of sugars and for monitoring levels of other solution components known to affect the activity of enzymes. The use of this strategy to normalize raw fluorescence signals is demonstrated by the determination of glucose and pH on a single chip. Alternatively, uncertainties in the activity of an immobilized enzyme can be accounted for using standard additions, an approach used here in the determination of serum glucose.

Development of multianalyte sensor arrays composed of chemically derivatized polymeric microspheres localized in micromachined cavities

The development of a chip-based sensor array composed of individually addressable polystyrene-poly(ethylene glycol) and agarose microspheres has been demonstrated. The microspheres are selectively arranged in micromachined cavities localized on silicon wafers. These cavities are created with an anisotropic etch and serve as miniaturized reaction vessels and analysis chambers. A single drop of fluid provides sufficient analysis media to complete approximately 100 assays in these microetch pits. The cavities possess pyramidal pit shapes with trans-wafer openings that allows for both fluid flow through the microreactors/analysis chambers and optical access to the chemically sensitive microspheres. Identification and quantitation of analytes occurs via colorimetric and fluorescence changes to receptor and indicator molecules that are covalently attached to termination sites on the polymeric microspheres. Spectral data are extracted from the array efficiently using a charge-coupled device allowing for the near-real-time digital analysis of complex fluids. The power and utility of this new microbead array detection methodology is demonstrated here for the analysis of complex fluids containing a variety of important classes of analytes including acids, bases, metal cations, metabolic cofactors, and antibody reagents.

Numerical simulation and visualization of elastic waves using mass-spring lattice model

A computer program package has been developed for simulation and visualization of two-dimensional elastic wave propagation and scattering using the mass-spring lattice model (MSLM) and, for comparison, a finite difference model. To assess the reliability of the numerical schemes, their convergence and accuracy have been analysed using the Taylor series expansion and the von Neumann analysis methods. As a result, the grid spacing-time increment combinations previously adopted in the literature have proved to be non-optimal. The optimal combinations have been found and shown to yield the most accurate results with the least computation time, particularly in the high frequency regime. Using these algorithms, a program package has been developed in Visual C++ (Microsoft, Redmond, WA) with graphic user interfaces for convenient exploration of visualized results. Numerical results have been obtained for some fundamental problems in ultrasonic testing such as plane waves incident on cracks. All numerical results have shown excellent qualitative agreements with the analytical results of the wave physics, as the reflected, diffracted, head, and Rayleigh waves have been observed. Also, for numerical results with anisotropic media, the cusps on the shear wavefronts have been observed. Finally, slight modification of the modeling method for free surfaces has led to more accurate prediction of Rayleigh waves.

Anti-tumor promoting potential of naturally occurring diarylheptanoids structurally related to curcumin

In recent years, there have been considerable efforts to search for naturally occurring substances for intervention of carcinogenesis. Many components from medicinal or dietary plants have been identified to possess potential chemopreventive properties. For instance, curcumin, a yellow colouring agent from turmeric (Curcuma longa Linn., Zingiberaceae) has been shown to inhibit tumor formation in diverse animal models. Alpinia oxyphylla Miquel that also belongs to ginger family has been used in oriental herbal medicine. In the present work, we have evaluated the anti-tumor promoting potential of yakuchinone A (1-[4'-hydroxy-3'-methoxyphenyl]-7-phenyl-3-heptanone) and yakuchinone B (1-[4'-hydroxy-3'-methoxyphenyl]-7-phenylhept-1-en-3-one), major pungent ingredients of A. oxyphylla. Thus, topical application of yakuchinone A or B significantly suppressed TPA-induced epidermal ornithine decarboxylase activity. They also reduced TPA-stimulated production of tumor necrosis factor-alpha in cultured human promyelocytic leukemia (HL-60) cells. Both compounds blunted the TPA-induced superoxide generation in differentiated HL-60 cells in a concentration-related manner and also inhibited lipid peroxidation in rat brain homogenates. Furthermore, yakuchinone A and yakuchinone B nullified the activation of the activator protein-1 (AP-1) in immortalized mouse fibroblast cells in culture. These findings indicate that pungent diarylheptanoids from A. oxyphylla have anti-tumor promotional properties that can contribute to their chemopreventive potential.

Chemopreventive effects of 2-(allylthio)pyrazine on hepatic lesion, mutagenesis and tumorigenesis induced by vinyl carbamate or vinyl carbamate epoxide

2-(Allylthio)pyrazine (2-AP), synthesized for its possible use as a hepatoprotective agent, has been found to selectively inhibit rat hepatic cytochrome P450 2E1 (Kim et al., Biochem. Pharmacol., 53, 261-269, 1997), while it enhances the activities of phase II detoxification enzymes such as glutathione S-transferase and epoxide hydrolase. As part of a program in evaluating the chemopreventive potential of 2-AP, we have determined its effects on hepatotoxicity, mutagenicity and tumorigenicity of vinyl carbamate (VC), a prototypic hepatocarcinogen preferentially activated by P450 2E1 to the ultimate carcinogenic metabolite vinyl carbamate epoxide (VCO), which undergoes detoxification by glutathione conjugation and oxirane hydrolysis. Administration of 2-AP (100 mg/kg body wt) to male Sprague-Dawley rats by gavage, 2 days, 1 day and 4 h prior to VC or VCO, markedly ameliorated the hepatotoxicity of these compounds as determined by decreased serum aspartate aminotransferase and alanine aminotransferase activities. Furthermore, 2-AP pre-treatment significantly suppressed the VC-induced hepatocarcinogenesis in infant male B6C3F1 mice. In a separate experiment, the multiplicities of skin tumors formed in female ICR mice treated with 5.8 micromol of VC or VCO were inhibited 58 and 70%, respectively, by pre-treatment with 2-AP by oral administration. The mutational spectrum of ras-oncogene in papillomas was not altered by 2-AP pre-treatment. 2-AP also inhibited the mutagenicity of VC in the Salmonella-microsome assay. Taken together, these findings suggest that 2-AP is a potential chemopreventive agent.

Inhibition of vinyl carbamate-induced hepatotoxicity, mutagenicity, and tumorigenicity by isopropyl-2-(1,3-dithietane-2-ylidene)-2-[N-(4-methylthiazol-2- yl)carbamoyl]acetate (YH439)

Isopropyl-2-(1,3-dithietane-2-ylidene)-2-[N-(4-methylthiazol -2-yl)carbamoyl]acetate (YH439) is a novel dithioylidene malonate derivative developed for the treatment of hepatic injury. The compound has been found to down-regulate the expression of hepatic cytochrome P-450 2E1 (CYP2E1) at the transcriptional level (8). Certain organosulfur compounds present in garlic elicit protective effects on chemically induced carcinogenesis and mutagenesis and their chemopreventive activities are associated in part with inhibition of CYP2E1. As part of a program to determine the likely chemopreventive potential of YH439, we initially examined its effects on hepatotoxicity induced by vinyl carbamate (VC), a proximate carcinogen that is preferentially bioactivated by CYP2E1. A single i.p. injection of VC (125 mg/kg body wt) to male Sprague-Dawley rats resulted in severe hepatic lesions as demonstrated by elevated levels of serum enzymes such as alanine aminotransferase and aspartate aminotransferase. Histopathological evaluation of liver sections from VC-treated animals revealed that the hepatic damage mainly consisted of centrilobular necrosis with sinusoidal congestion. Oral administration of YH439 (200 mg/kg body wt) to male Sprague-Dawley rats 2 days, 1 day and 4 h prior to VC completely prevented the hepatic damage caused by this carcinogen. In another experiment, rat hepatic microsome-mediated bacterial mutagenicity of VC was suppressed by YH439 in a dose-related manner. Furthermore, pretreatment of female CD-1 mice with YH439 by gastric intubation resulted in diminution of VC-induced skin carcinogenesis.

Early changes in circulating blood volume and volume regulating humoral factors after implantation of an electrohydraulic total artificial heart

The early changes in circulating blood volume (CBV) and volume regulating humoral factors after implantation of an electrohydraulic total artificial heart (EH-TAH) were investigated in a calf and compared with results in a sham operated control calf. CBV was measured by the dye dilution method using indocyanine green. CBV and humoral factors were periodically investigated. In the EH-TAH implanted calf, the cardiac output was estimated at 6-7 L/ min (94-109 ml/kg/min), and the aortic pressure and aerobic metabolic condition were favorable. Nevertheless, the CBV was increased to 132 and 168% of the pre-operative value (range in the control calf, 83-103%) on post operative days 4 and 8, respectively. The atrial natriuretic peptide level on days 2, 5, and 7 was 23, 170, and 240 (in the control calf, 19-61) pg/ml, respectively, and the antidiuretic hormone level was 7.3, 2.0, and 1.3 (0.5-1.3) pg/ ml, respectively. The plasma renin activity was 3.2, 3.7, and 3.1 (0.5-0.3) ng/ml/hr, respectively. The angiotensin-I and angiotensin-II levels were also increased in the EH-TAH implanted calf. It is concluded that significant water retention occurs even at sufficient cardiac output early after EH-TAH implantation. The changes in humoral factors are suggested to arise secondary to the increased CBV or other unknown factors.

The electrophilic, mutagenic and tumorigenic activities of phenyl and 4-nitrophenyl vinyl ethers and their epoxide metabolites

The metabolism and mutagenicity of phenyl and 4-nitrophenyl vinyl ethers (PVE and NPVE) and their epoxide metabolites, phenoxyoxirane (PO) and 2'-(4-nitro-phenoxy)oxirane (NPO), were studied including reactions with DNA and tests for carcinogenicity. PVE and NPVE were epoxidized in dry acetone by dimethyldioxirane to give high yields (95%) of the pure epoxides. The epoxides are unstable in aqueous media and in 0.1 N phosphate buffer, pH 7.4, at 37 degrees C; they had half-lives of 2.7 min (PO) and 4.4 min (NPO). These times were reduced to 1.9 min (PO) and 2.5 min (NPO) in the presence of isotonic (154 mM) chloride ion. In neutral phosphate buffer these epoxides hydrolyze to form glycolaldehyde and the corresponding phenols; in the presence of chloride ion, chloroacetaldehyde and several unknown compounds are also formed. Glycolaldehyde was also found as a hydrolysis product of the presumed epoxides generated in the hepatic microsomal oxidation of PVE and NPVE. PO and NPO reacted with DNA to form adducts that depurinated in weak acid to form 7-(2'-oxoethyl)guanine and N(2),3-ethenoguanine. PO was weakly mutagenic in Salmonella typhimurium TA1535 while NPO was much more mutagenic under the same conditions. PO and NPO were found to have mutagenic half-lives that matched their chemical half-lives. PO and NPO were found to be tumorigenic in the skin of mice after single or five initiating doses followed by multiple doses of phorbol ester (TPA). NPO was a stronger tumor initiator than PO. NPO had appreciable activity as an initiator of hepatoma formation in infant male B6C3F1 mice. Thus PO and NPO are electrophilic, mutagenic and tumorigenic metabolites of their corresponding phenyl vinyl ethers.