Perioperative Pulmonary Atelectasis: Part II. Clinical Implications

The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient’s safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.

Processing of slow-global auditory regularities causes larger neural responses to heartbeats in patients under minimal consciousness state, compared to unresponsive wakefulness syndrome

Objectives: Determine if contextual processing of auditory regularities (local-global paradigm) modulate the heartbeat-evoked responses (HERs), and if these modulations may provide complementary information to the auditory related potentials to facilitate the diagnose of patients with disorders of consciousness (DOC). Methods: DOC patients underwent the local-global paradigm to evaluate the cognitive processing of short/long term-auditory regularities. High-density EEG was recorded to evaluate HERs in local, global and overall conditions. Results: The global effect triggers higher HERs, as well as overall higher HER variance appears in minimally conscious patients. The variance and amplitude effects were uncorrelated, indicating different cognitive processes. Discussion: Our results corroborate previous findings on HER variance, a marker able to separate DOC without specific stimulations. HER modulations in response to global auditory irregularities represents a novel neural signature of consciousness access, which may facilitate the bedside diagnosis of state of consciousness with more affordable options to neuroimaging methods.

The diagnostic value of Doppler ultrasonography after pediatric kidney transplantation

Ultrasonography (US) plays a major diagnostic role in the pre- and post-transplant evaluation of recipient and donor. In most cases, US remains the only necessary imaging modality. After pediatric kidney transplantation, US can ensure immediate bedside diagnosis of vessel patency and possible postoperative non-vascular complications. Criteria for US diagnosis of kidney vessel thrombosis and stenosis in the transplant will be presented. Non-vascular complications after kidney transplantation include hydronephrosis, hematoma, lymphocele, and abscess. US can detect suggestive, but nevertheless non-specific, acute signs (sudden increase in volume and elevated resistive index), and chronic rejection, which therefore remains a histological diagnosis. US is of little or no help in detection of tubular necrosis or drug toxicity, but it can exclude other differential diagnoses. This educational review provides a practical and systematic approach to a multimodal US investigation of the kidney transplant. It includes a short overview on possible indications for contrast-enhanced ultrasonography (CEUS) in children after kidney transplantation.

Ultrasound examination as a method of early “bedside” diagnosis of acute kidney injury in geriatric patients after urgent abdominal surgery

Geriatric patients are particularly vulnerable to the development of postoperative complications, one of which is acute kidney injury (AKI). Early diagnosis of AKI is an important component of the effectiveness of its prevention and treatment. It is believed that ultrasound examination of renal blood flow may be a promising method for bedside diagnosis of AKI. The aim is to evaluate the predictive value of renal resistance index (RRI) and semiquantitative renal perfusion (SQP) as methods for early diagnosis of AKI in geriatric patients after urgent abdominal surgery. Materials and methods. A prospective single-center study included 40 patients (72.5 (65; 81.5) y. o.) who were assessed for the risk of development, the presence and stage of AKI, and additionally measured hemodynamic parameters, intra-abdominal pressure (IAP), and abdominal perfusion pressure (APP). Renal resistance index (RRI) and semi-quantitative renal perfusion score (SQP) were determined using Doppler ultrasound (ultrasound probe CH-6, SIEMENS, Acuson Antares). Statistical analysis was performed using the STATISTICA for Windows 13 program (StatSoftInc., No. JPZ804I382130ARCN10-J). Results. In the postoperative period, AKI developed in 26 patients (65%). Compared with patients without AKI, they had a 14% lower level of mean arterial pressure (MAP) (p=0.008), as well as an average of 4 mmHg higher IAP (p=0.005) and significantly lower APP (p=0.0348). Correlation analysis revealed a weak relationship between the values of MAP, IAP, APP and the development of AKI (r=0.34, r=0.41, r=0.392, respectively, p˂0.05). Patients with AKI had a 13.9% higher RRI than patients without AKI (0.75 (0.72; 0.81) r.u. vs 0.66 (0.61; 0.69) r.u., respectively, p=0.000001), however, the degree of SQP of the kidneys did not differ significantly between the groups (p=0.636). The correlation between the RRI and the development of AKI was of moderate strength (r=0.57, p˂0.05). MAP, IAP, and APP were significantly very weakly correlated with RRI (r=0.34; r=0.41, r=0.392, respectively, p˂0.05). ROC analysis showed that RRI>0.71 r.u. is the threshold level for AKI with 87.2% sensitivity and 73.5% specificity, and it has a high predictive value (area under the curve AUC 0.868 (p<0.0001)). Conclusions. High RRI values are associated with AKI in geriatric patients after urgent abdominal surgery. RRI may be a bedside diagnostic tool for AKI, in contrast to renal SQP, which has shown no predictive value.

Fibroblast Activation Protein-α as a Target in the Bench-to-Bedside Diagnosis and Treatment of Tumors: A Narrative Review

Fibroblast activation protein-α (FAP) is a type II integral serine protease that is specifically expressed by activated fibroblasts. Cancer-associated fibroblasts (CAFs) in the tumor stroma have an abundant and stable expression of FAP, which plays an important role in promoting tumor growth, invasion, metastasis, and immunosuppression. For example, in females with a high incidence of breast cancer, CAFs account for 50–70% of the cells in the tumor’s microenvironment. CAF overexpression of FAP promotes tumor development and metastasis by influencing extracellular matrix remodeling, intracellular signaling, angiogenesis, epithelial-to-mesenchymal transition, and immunosuppression. This review discusses the basic biological characteristics of FAP and its applications in the diagnosis and treatment of various cancers. We review the emerging basic and clinical research data regarding the use of nanomaterials that target FAP.

Detection of Volatile Organic Compounds as Potential Novel Biomarkers for Chorioamnionitis – Proof of Experimental Models

Background: Histologic chorioamnionitis is only diagnosed postnatally which prevents interventions. We hypothesized that volatile organic compounds (VOCs) in the amniotic fluid might be useful biomarkers for chorioamnionitis and that VOC profiles differ between amnionitis of different origins.Methods: Time-mated ewes received intra-amniotic injections of media or saline (controls), or live Ureaplasma parvum serovar 3 (Up) 14, 7 or 3d prior to c-section at day 124 gestational age (GA). 100 μg recombinant ovine IL-1α was instilled at 7, 3 or 1d prior to delivery. Headspace VOC profiles were measured from amniotic fluids at birth using ion mobility spectrometer coupled with multi-capillary columns.Results: 127 VOC peaks were identified. 27 VOCs differed between samples from controls and Up- or IL-1α induced amnionitis. The best discrimination between amnionitis by Up vs. IL-1α was reached by 2-methylpentane, with a sensitivity/specificity of 96/95% and a positive predictive value/negative predictive values of 96 and 95%. The concentration of 2-methylpentane in VOCs peaked 7d after intra-amniotic instillation of Up.Discussion: We established a novel method to study headspace VOC profiles of amniotic fluids. VOC profiles may be a useful tool to detect and to assess the duration of amnionitis induced by Up. 2-methylpentane was previously described in the exhalate of women with pre-eclampsia and might be a volatile biomarker for amnionitis. Amniotic fluids analyzed by ion mobility spectrometry coupled with multi-capillary columns may provide bedside diagnosis of amnionitis and understanding inflammatory mechanisms during pregnancy.

Serological Rapid Test for Diagnosis of SARS-COVv-2 Works Also on Gastro-intestinal Tissue Samples of COVID-19 Patients: Practical Aspects of Single Center Observational Study.

SARS-COV-2 infection spreading becomes a long and challenging medical question. The possibility to improve the diagnosis of SARS-COV-2 infection in digestive endoscopy is important because gastrointestinal symptoms can be the presenting symptoms of COVID-19.We tried to obtain a fast and “bedside” diagnosis of gastrointestinal COVID-19 by performing serological rapid test to verify the presence of SARS-COV-2 in gastrointestinal mucosal specimens.From the 4th to the 30th January 2021, regular mucosal biopsies were taken from stomach, ileum or colon of 10 COVID-19 patients (7M, 3F, mean age: 49.7 y.o.) and from 10 negative patients ( 6M, 4F, mean age: 50 y.o.) according to standard clinical indications. One specimen for each patient was placed in a sterile test-tube with 5 drops of standard reagent for rapid serological test for 10 minutes.After that period, both the specimen and the drops were put on the platform for serological rapid tests. In all COVID-19 patients, tests were positive for both IgG and IgM bands (and control bands, confirming that the test worked properly). Otherwise, the analysis of gastrointestinal specimen of negative patients showed only the control band.No differences were found for different specimens (stomach, colon or ileum). Statistical analysis conducted to compare the results of the two groups confirmed the difference between COVID-19 positive and negative groups.Applying this kind of analysis, we can immediately verify if gastrointestinal symptoms (especially diarrhea) of a non-tested patient are related to SARS-COV-2 infection and we can use this test as a rapid test in case of suspected endoscopic findings to confirm the association with SARS-COV-2 infection.In the end, the test can contribute to help in the differential diagnosis of gastrointestinal manifestations considering the long-term management of SARS-COV-2 infections.