Análisis de la fotopletismografía para determinación de variaciones en el tono vascular y la presión arterial: Estudio basado en redes neuronales / Photoplethys mography waveform analysis for classification of vascular tone and arterial blood pressure: Study based on neural networks

Antecedentes y objetivo: El propósito del presente estudio fue evaluar si una red neuronal superficial (RN-S) puede detectar y clasificar los cambios en la presión arterial (PA), dependientes del tono vascular mediante un análisis del contorno de la onda de fotopletismografía (FPG). Material y métodos: Las señales de FPG y PA invasivas fueron simultáneamente registradas en 26 pacientes programados para cirugía general. Se estudió la aparición de episodios de hipertensión (presión arterial sistólica (PAS) > 140 mmHg), normotensión e hipotensión (PAS < 90 mmHg). El tono vascular fue clasificado según la FPG en dos formas: 1) Mediante inspección visual de los cambios en la amplitud de la onda de FPG y en la posición de la incisura dícrota; donde las clases I-II representan vasoconstricción (incisura dícrota ubicada a > 50% de la amplitud de FPG en ondas de pequeña amplitud), tono vascular normal de clase III (incisura dícrota ubicada entre 20-50% de la amplitud de FPG en ondas normales) y vasodilatación de clases IV-V-VI (incisura dícrota a < 20% de la amplitud FPG en ondas grandes). 2) Mediante un análisis automatizado basado en RN-S que combina siete parámetros derivados de la onda de FPG. Resultados: La evaluación visual fue precisa en la detección de hipotensión (sensibilidad 91%, especificidad 86% y precisión 88%) e hipertensión (sensibilidad 93%, especificidad 88% y precisión 90%). La normotensión se presentó como clase visual III (III-III) (mediana y 1°- 3° cuartiles), hipotensión como clase V (IV-VI) e hipertensión como clase II (I-III); todos con significancia estadística (p < 0,0001). La RN-S funcionó bien en la clasificación de las condiciones de PA. El porcentaje de datos con clasificación correcta por la RN-S fue del 83% para normotensión, 94% para hipotensión y 90% para hipertensión. Conclusiones: Los cambios en la PA inducidos por alteraciones en el tono vascular fueron clasificados correctamente de forma automática con una RN-S con base en...(AU)

Background: To test whether a Shallow Neural Network (S-NN) can detect and classify vascular tone dependent changes in arterial blood pressure (ABP) by advanced photopletysmographic (PPG) waveform analysis. Methods: PPG and invasive ABP signals were recorded in 26 patients undergoing scheduled general surgery. We studied the occurrence of episodes of hypertension (systolic arterial pressure (SAP) > 140 mmHg), normotension and hypotension (SAP < 90 mmHg). Vascular tone according to PPG was classified in two ways: 1) By visual inspection of changes in PPG waveform amplitude and dichrotic notch position; where Classes I-II represent vasoconstriction (notch placed > 50% of PPG amplitude in small amplitude waves), Class III normal vascular tone (notch placed between 20-50% of PPG amplitude in normal waves) and Classes IV-V-VI vasodilation (notch < 20% of PPG amplitude in large waves). 2) By an automated analysis, using S-NN trained and validated system that combines seven PPG derived parameters. Results: The visual assessment was precise in detecting hypotension (sensitivity 91%, specificity 86% and accuracy 88%) and hypertension (sensitivity 93%, specificity 88% and accuracy 90%). Normotension presented as a visual Class III (III-III) (median and 1st-3rd quartiles), hypotension as a Class V (IV-VI) and hypertension as a Class II (I-III); all p < 0.0001. The automated S-NN performed well in classifying ABP conditions. The percentage of data with correct classification by S-ANN was 83% for normotension, 94% for hypotension, and 90% for hypertension. Conclusions: Changes in ABP were correctly classified automatically by S-NN analysis of the PPG waveform contour.(AU)

Photoplethysmography waveform analysis for classification of vascular tone and arterial blood pressure: Study based on neural networks.

BACKGROUND: To test whether a Shallow Neural Network (S-NN) can detect and classify vascular tone dependent changes in arterial blood pressure (ABP) by advanced photopletysmographic (PPG) waveform analysis. METHODS: PPG and invasive ABP signals were recorded in 26 patients undergoing scheduled general surgery. We studied the occurrence of episodes of hypertension (systolic arterial pressure (SAP) >140 mmHg), normotension and hypotension (SAP < 90 mmHg). Vascular tone according to PPG was classified in two ways: 1) By visual inspection of changes in PPG waveform amplitude and dichrotic notch position; where Classes I-II represent vasoconstriction (notch placed >50% of PPG amplitude in small amplitude waves), Class III normal vascular tone (notch placed between 20-50% of PPG amplitude in normal waves) and Classes IV-V-VI vasodilation (notch <20% of PPG amplitude in large waves). 2) By an automated analysis, using S-NN trained and validated system that combines seven PPG derived parameters. RESULTS: The visual assessment was precise in detecting hypotension (sensitivity 91%, specificity 86% and accuracy 88%) and hypertension (sensitivity 93%, specificity 88% and accuracy 90%). Normotension presented as a visual Class III (III-III) (median and 1st-3rd quartiles), hypotension as a Class V (IV-VI) and hypertension as a Class II (I-III); all p < .0001. The automated S-NN performed well in classifying ABP conditions. The percentage of data with correct classification by S-ANN was 83% for normotension, 94% for hypotension, and 90% for hypertension. CONCLUSIONS: Changes in ABP were correctly classified automatically by S-NN analysis of the PPG waveform contour.

Ultrasound-guided brachiocephalic vein access in neonates and pediatric patients.

Central venous accesses in neonates and pediatric patients represent a common and important procedure for both, intraoperative and postoperative care. Point-of-care ultrasound-guided technique has been proposed to increased success rate and efficiency, as well as to decrease the number of complications. Ultrasound-guided internal jugular vein cannulation is considering the "gold standard" in children. Another central venous cannulation option in neonates and children has been supraclavicular ultrasound-guided cannulation of the brachiocephalic vein using the in-plane approach. This article gives a review of the current evidence, the basic knowledge of the technique and the structured approach to follow for supraclavicular ultrasound-guided brachiocephalic vein access in children and neonates.

Ultrasound-guided brachiocephalic vein access in neonates and pediatric patients. / Accesos vasculares ecoguiados de la vena braquiocefálica en neonatos y pacientes pediátricos.

Central venous accesses in neonates and pediatric patients represent a common and important procedure for both, intraoperative and postoperative care. Point-of-care ultrasound-guided technique has been proposed to increased success rate and efficiency, as well as to decrease the number of complications. Ultrasound-guided internal jugular vein cannulation is considering the "gold standard" in children. Another central venous cannulation option in neonates and children has been supraclavicular ultrasound-guided cannulation of the brachiocephalic vein using the in-plane approach. This article gives a review of the current evidence, the basic knowledge of the technique and the structured approach to follow for supraclavicular ultrasound-guided brachiocephalic vein access in children and neonates.

Quality of Life During and After Completion of Neoadjuvant Chemoradiotherapy for Esophageal and Junctional Cancer.

BACKGROUND: The course of health-related quality of life (HRQOL) during and after completion of neoadjuvant chemoradiotherapy (nCRT) for esophageal or junctional carcinoma is unknown. METHODS: This study was a multicenter prospective cohort investigation. Patients with esophageal or cancer to be treated with nCRT plus esophagectomy were eligible for inclusion in the study. The HRQOL of the patients was measured with European Organization for Research and Treatment of Cancer QLQ-C30, QLQ-OG25, and QLQ-CIPN20 questionnaires before and during nCRT, then 2, 4, 6, 8, 10, 12, 14, and 16 weeks after nCRT and before surgery. Predefined end points were based on the hypothesized impact of nCRT. The primary end points were physical functioning, odynophagia, and sensory symptoms. The secondary end points were global quality of life, fatigue, weight loss, and motor symptoms. Mixed modeling analysis was used to evaluate changes over time. RESULTS: Of 106 eligible patients, 96 (91%) were included in the study. The rate of questionnaires returned ranged from 94% to 99% until week 12, then dropped to 78% in week 16 after nCRT. A negative impact of nCRT on all HRQOL end points was observed during the last cycle of nCRT (all p < 0.001) and 2 weeks after nCRT (all p < 0.001). Physical functioning, odynophagia, and sensory symptoms were restored to pretreatment levels respectively 8, 4, and 6 weeks after nCRT. The secondary end points were restored to baseline levels 4-6 weeks after nCRT. Odynophagia, fatigue, and weight loss improved after nCRT compared with baseline levels at respectively 6 (p < 0.001), 16 (p = 0.001), and 12 weeks (p < 0.001). CONCLUSION: After completion of nCRT for esophageal cancer, HRQOL decreases significantly, but all HRQOL end points are restored to baseline levels within 8 weeks. Odynophagia, fatigue, and weight loss improved 6-16 weeks after nCRT compared with baseline levels.

McConnell's sign in intra-operative acute right ventricle ischaemia: An under-recognized aetiology. / Signo de McConnell en isquemia aguda de ventrículo derecho intraoperatoria: una etiología poco reconocida.

Transoesophageal echocardiography (TEE) has become a fundamental tool in modern cardiothoracic anaesthesia. It has an indisputable role in coronary valve surgery and revascularisations with severe impairment of ventricle function. It helps in making diagnoses that can optimise the surgical strategy and to minimal invasively dynamically monitor volaemia and cardiac function during the post-operative period, detecting complications unobservable by other methods. The McConnell sign, visualised using TEE as an akinesis of the right ventricular free wall, with a normal apex motility and enlargement of the right cavities, is characteristic of right ventricular (RV) dysfunction. This sign has a 77% sensitivity and 94% specificity for the diagnosis of acute pulmonary embolism (APE). The case is presented of a 53-year-old man scheduled for aortic valve and ascending aorta replacement surgery, with a history of severe valve aortic stenosis, aortic root and arch aneurysm, and with normal coronary arteries. Post-cardiopulmonary bypass (CBP), the patient presented with haemodynamic instability, with the TEE showing a typical image of the McConnell sign, with no pulmonary hypertension. This enabled making an early diagnosis of acute RV ischaemia, that led to a change in the surgical plan, the performing of coronary revascularisation surgery. As a result, the McConnell sign, which describes the characteristics of RV dysfunction, led to making a differential diagnosis between APE, RV infarction and acute myocardial ischaemia.

Exploring the role of nerve growth factor in multiple sclerosis: implications in myelin repair.

Multiple sclerosis (MS) is a chronic disease resulting from targeted destruction of central nervous system (CNS) myelin. MS is suggested to be an autoimmune disease involving the pathogenic activation of CD4(+) T cells by a foreign antigen in the peripheral blood. The activated CD4(+) T cells liberate inflammatory cytokines that facilitate the breakdown of the blood-brain barrier (BBB) promoting their passage into the CNS. Inside the CNS, CD4(+) T cells become re-activated by myelin proteins sharing a similar structure to the foreign antigen that initially triggered the immune response. The CD4(+) T cells continue to liberate inflammatory cytokines, such as tumor necrosis factor α (TNFα), which activates macrophages and antibodies responsible for the phagocytosis of myelin. Acute CNS lesions can be re-myelinated, however, the repair of chronic demyelinating lesions is limited, leading to permanent neurological deficits. Although current MS treatments reduce severity and slow disease progression, they do not directly repair damaged myelin. Henceforth, recent treatment strategies have focused on neurotrophins, such as nerve growth factor (NGF) for myelin repair. NGF promotes axonal regeneration, survival, protection and differentiation of oligodendrocytes (OGs) and facilitates migration and proliferation of oligodendrocyte precursors (OPs) to the sites of myelin damage. NGF also directly regulates key structural proteins that comprise myelin. Interestingly, NGF also induces the production of brain-derived neurotrophic factor (BDNF), another integral neurotrophin involved in myelination. The intricate signaling between neurotrophins and cytokines that governs myelin repair supports the role of NGF as a leading therapeutic candidate in white matter disorders, such as MS.