The influence of hemodialysis on intracranial pressure waveform in patients with chronic kidney disease: an observational study

ABSTRACT BACKGROUND: Among the complications related to chronic kidney disease (CKD), those of a neurological nature stand out, and for a better quality of life for patients, the diagnosis and treatment of these complications is fundamental. OBJECTIVES: This study aimed to assess the effect of hemodialysis on intracranial pressure waveform (ICPw) in patients with chronic kidney disease undergoing hemodialysis and those who are not yet undergoing substitutive therapy. DESIGN AND SETTING: An observational study was conducted in two stages at a kidney replacement therapy center in Brazil. The first was a longitudinal study and the second was a cross-sectional study. METHODS: Forty-two patients on hemodialysis were included in the first stage of the study. In the second stage, 226 participants were included. Of these, 186 were individuals with chronic kidney disease (who were not undergoing substitutive therapy), and 40 did not have the disease (control group). The participants' intracranial compliance was assessed using the non-invasive Brain4care method, and the results were compared between the groups. RESULTS: There was a significant difference between the hemodialysis and non-hemodialysis groups, with the former having better ICPw conditions. CONCLUSIONS: Hemodialysis influenced the improvement in ICPw, probably due to the decrease in the patients' extra-and intracellular volumes. Furthermore, ICPw monitoring can be a new parameter to consider when defining the moment to start substitutive therapy.

Deadly ECG Sign: An Aspect to Recognize in the Settings of STEMI

Learning Objectives: Learn how to identify and differentiate the shark fin EKG pattern from other EKG patterns and abnormalities. Explore the potential diagnostic and prognostic implications of the shark fin EKG pattern, including its association with increased risk of arrhythmias and sudden cardiac death. Background: The Lambda-wave ECG, also known as the Shark fin or Thombostone pattern, has been linked to ST-elevation myocardial infarction's (STEMI) hazardous implications. It is characterized by merged QRS, ST, and T waves, forming a 'triangular QRS-ST-T waveform' or 'giant R waves.' This treacherous signature poses an alarming risk, with chances of cardiogenic shock and ventricular fibrillation leading to fatality. To tackle this peril, implementing swift thrombolysis or percutaneous intervention for reperfusion is critical for successful treatment. For optimal outcomes, the preferred setting to utilize ventricular assist devices is the ICU. Misdiagnosis can happen and be seen as either wide complex tachycardia or ECG changes induced by hyperkalemia. Imperative to prevent severe complications, early detection and treatment are crucial. We are reporting three cases of this Ekg pattern.

A Ventricular Fibrillation Recognition Method Based on Random Forest and BP Neural Network / 中国医疗器械杂志

Ventricular fibrillation is the most common pathophysiological mechanism leading to cardiac arrest. If cardiac arrest can be rescued in time, the survival rate of patients can be greatly improved. Therefore, rapid and accurate identification of ventricular fibrillation is extremely important. This paper proposes an automatic detection algorithm for ventricular fibrillation based on random forest and BP (back propagation) neural network. Pass the ECG signal through a 6 s moving window, calculate 6 kinds of characteristic parameters according to the time-frequency domain information of the signal, use these 6 kinds of characteristic parameters as the input of the classifier, carry out classification and test, and give the authoritative experts in the database. A total of 44 cases of related data were used to evaluate the method. The results show that using the ten-fold cross-validation method, the accuracy of classification of ventricular fibrillation in the CU database (Creighton University Ventricular Tachyarrhythmia Database) and the AHA database (the American Heart Association Database) has reached 96.38% and 99.45%, which has certain applicability.

The correlation between carotid blood flow and the parameters derived by pulse oximetry plethysmographic waveform during cardiopulmonary resuscitation in a porcine model / 中华急诊医学杂志

Objective:To explore the correlation between carotid blood flow and the parameters derived by pulse oximetry Plethysmographic waveform in cardiopulmonary resuscitation, so as to provide a new index for carotid blood flow monitoring in cardiopulmonary resuscitation.Methods:Seven male domestic pigs were utilized for cardiac arrest model through ventricular fibrillation induced by electrical stimulation. Eight minutes after cardiac arrest, artificial chest compression was given for 4 min, and epinephrine 20 μg/kg was injected intravenously at 2 min after chest compression. The compression frequency, compression depth, right carotid blood flow, pulse oximetry plethysmographic waveform, aortic pressure, right atrium pressure and end tidal carbon dioxide partial pressure were continuously monitored and recorded. From 30 s to 4 min after chest compression, the values of the mean right carotid blood flow, the area under curve (AUC) of pulse oximetry plethysmographic waveform, the mean perfusion index, the mean coronary perfusion pressure and the average end-tidal carbon dioxide partial pressure during 6 s before time point were calculated every 30 s. The correlations between right carotid blood flow and the AUC of pulse oximetry plethysmographic waveform and perfusion index were analyzed respectively.Results:Ventricular fibrillation was induced successfully in seven animals. There were no significant differences in the mean chest compression frequency and depth per min during 4 min of chest compression. Right carotid blood flow at 30 s after chest compression was (92.7±32.7) mL/min, and decreased to (48.5±23.5) mL/min at 1 min after chest compression ( P<0.05). There was no significant difference in blood flow before and after epinephrine injection ( P>0.05). The AUC of the blood oxygen plethysmographic waveform and perfusion index showed synchronous change trends with right carotid blood flow. Both coronary perfusion pressure and end-tidal carbon dioxide partial pressure showed different change trends with right carotid blood flow. There was a positive correlation between the right carotid blood flow and the AUC of blood oxygen plethysmographic waveform ( r=0.66, P<0.01), and also a positive correlation between right carotid blood flow and perfusion index ( r=0.57, P<0.01). Conclusions:Carotid blood flow is positively correlated with the AUC of blood oxygen plethysmographic waveform and perfusion index in a porcine model of cardiopulmonary resuscitation. Real-time monitoring of the two parameters derived by pulse oximetry plethysmographic waveform can reflect the changes of carotid blood flow to a certain extent.

Quantitative analysis of the effect of contact pressure on the reflection characteristics of radial pressure wave / 生物医学工程学杂志

The radial artery pulse wave contains a wealth of physiological and pathological information about the human body, and non-invasive studies of the radial artery pulse wave can assess arterial vascular elasticity in different age groups.The piezoelectric pulse wave transducers were used to non-invasively acquire radial artery pulse waves at different contact pressures in young and middle-aged and elderly populations. The radial artery waveforms were decomposed using a triangular blood flow model fitting method to obtain forward and reflected waves and calculate reflection parameters. Finally a correlation analysis and regression analysis of the contact pressure Psensor with the reflection parameters was carried out. The results showed that the reflection parameters RM, RI and Rd had a strong negative correlation with Psensor in both types of subjects, and the correlation coefficients and slopes of the regression curves were significantly different between the two types of subjects (P<0.05). Based on the results of this study, excessive contact pressure on the transducer should be avoided when detecting radial artery reflection waves in clinical practice. The results also show that the magnitude of the slope of the regression curve between the reflection parameters and the transducer contact pressure may be a potentially useful indicator for quantifying the elastic properties of the vessel.

A novel wearable transcutaneous tibial nerve stimulator inhibits bladder reflexes in cats / 中国康复理论与实践

ObjectiveTo observe the inhibitory effects of a novel wearable transcutaneous tibial nerve stimulator on bladder reflex in cats under different stimulation parameters. MethodsA total of 18 cats were divided into intensities, frequencies and waveforms groups, which wore the stimulator on the ankles and stimulated in different threshold (T) intensities (1/2 T, 1 T, 3/2 T and 2 T), frequencies (5 Hz, 10 Hz, 15 Hz and 30 Hz) and waveforms (A and B). The cats were anesthetized and infused normal saline to induce bladder reflex, while the bladder capacity was measured. Cystometrograms were compared among stimulation parameters. ResultsThe bladder capacity was not significantly different among the intensities (F = 1.997, P = 0.126), while the bladder capacity was more after TNS of 3/2 T and 2 T than baseline (P < 0.05). The bladder capacity was significantly different among the frequencies (F = 3.894, P = 0.014), while the bladder capacity was more after 5 Hz, 10 Hz and 15 Hz of TNS (P < 0.05). The bladder capacity was significantly different between the waveforms (F = 5.184, P = 0.019), while the bladder capacity was more after waveform A of TNS than baseline (P < 0.05). ConclusionThe novel wearable transcutaneous tibial nerve stimulator can effectively inhibit the physiological bladder reflex in cats, which associates to the intensity, frequency and waveform of stimulation.

Clinical application of clot waveform analysis / 中华检验医学杂志

Bleeding and thrombotic diseases are closely related to various clinical departments. Laboratory-related tests play an important role in disease diagnosis and differential diagnosis, risk assessment, cause finding, and efficacy monitoring. Clot waveform analysis (CWA), as an automated coagulation detection technology, can provide more valuable information about the entire coagulation process of a plasma sample. A large number of studies have showed that CWA has certain value in the evaluation of coagulation status of COVID-19 patients, the judgment of clinical phenotype of hemophilia A (HA) patients, and the monitoring of direct oral anticoagulant drugs (DOAC). In-depth interpretation and application of CWA in different clinical settings can provide more laboratory information for diagnosis and treatment of bleeding and thrombotic diseases.

Doppler ultrasound of umbilical artery in prediction of fetal outcome in pregnancy induced hypertension Sudanese population

The pregnancy induced hypertension increase the fetal mortality and morbidity and the using of Doppler umbilical artery indices decrease the fetal mortality and morbidity however, there is few complete data about the most frequently altered Doppler US parameters to predict fetal outcome in pregnancy induced hypertension . Methods This ia cohort prospective study done in two hundred and six women of second and third trimester presenting to antenatal clinic in Soba University Hospital at the department of Obstetrics & Gynecology, in the fetus unit and critical pregnancy in the period From June 2008 to April 2013 to assess the Doppler indices of umbilical artery in pregnancy induced hypertension for prediction of prenatal outcome; 105 pregnancy induced hypertension patients and 101 women with uneventful pregnancies as normal control group included in this study . Baseline investigations and color Doppler of umbilical artery were done. Statistical analysis of data were done using SPSS, Receiver Operating Characteristic (ROC) curve analysis was performed and the area under the curve (AUC) used to determine sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of umbilical artery Doppler indices to predict fetal outcome. Results The study determine that there was significant difference in Doppler indices in PIH and control group ( p<0.01, the mean indices of umbilical artery is higher in PIH group compared with normal pregnancy group , the mean different of S/D ratio was 0.40, mean difference of RI was 0.06 and the mean different of PI index was 0.16, high percentage of adverse fetal outcome had been reported in in Pregnancy Induced Hypertension group than in control , which was more in absent and reversed flow velocity in umbilical artery in Pregnancy Induced Hypertension compared with group of Pregnancy Induced Hypertension with present end diastolic flow velocity. Systolic/Diastolic ratio was most accurate in predicting adverse outcome in pregnancy induced hypertension patients, followed by the Pulastility index then the Resistance index (75%, 66% and 57% respectively). Conclusion This study concluded that pregnancy induced hypertension leads to worsen placental insufficiently, which appears on the higher Doppler indices of umbilical artery to PIH patients when compared with normal pregnancy. A low diastolic flow and higher indices characterized the pregnancies with abnormal outcomes. Doppler of the umbilical artery was useful to predict fetal well being in PIH patients, high percentage of adverse fetal outcome had been reported in absent and reversed end diastolic flow velocity in umbilical artery compared with group of present flow velocity.

Study on a quantitative analysis method for pulse signal by modelling its waveform in time and space domain / 生物医学工程学杂志

In order to quantitatively analyze the morphology and period of pulse signals, a time-space analytical modeling and quantitative analysis method for pulse signals were proposed. Firstly, according to the production mechanism of the pulse signal, the pulse space-time analytical model was built after integrating the period and baseline of pulse signal into the analytical model, and the model mathematical expression and its 12 parameters were obtained for pulse wave quantification. Then, the model parameters estimation process based on the actual pulse signal was presented, and the optimization method, constraints and boundary conditions in parameter estimation were given. The spatial-temporal analytical modeling method was applied to the pulse waves of healthy subjects from the international standard physiological signal sub-database Fantasia of the PhysioNet in open-source, and we derived some changes in heartbeat rhythm and hemodynamic generated by aging and gender difference from the analytical models. The model parameters were employed as the input of some machine learning methods, e.g. random forest and probabilistic neural network, to classify the pulse waves by age and gender, and the results showed that random forest has the best classification performance with Kappa coefficients over 98%. Therefore, the space-time analytical modeling method proposed in this study can effectively quantify and analyze the pulse signal, which provides a theoretical basis and technical framework for some related applications based on pulse signals.

Clinical efficacy of different waves of electroacupuncture on knee osteoarthritis and its effect on TGF-β1 in joint fluid / 中国针灸

OBJECTIVE@#To observe the therapeutic effects of different waves of electroacupuncture (EA) on knee osteoarthritis (KOA), and to explore the mechanism of different waves of EA on promoting cartilage repair.@*METHODS@#Ninety- seven patients with KOA were randomly divided into a dilatational wave group (32 cases, 2 cases dropped off), a continuous wave group (32 cases, 2 cases dropped off) and a discontinuous wave group (33 cases, 3 cases dropped off). The same acupoints of Xuehai (SP 10), Liangqiu (ST 34), Dubi (ST 35) and Neixiyan (EX-LE 4) were selected in the three groups. The dilatational wave (frequency of 2 Hz/10 Hz) was used in the dilatational wave group, the continuous wave (frequency of 10 Hz) was used in the continuous wave group, and the discontinuous wave (frequency of 10 Hz) was used in the discontinuous wave group. All the needles were retained for 30 min. All the treatment was given 3 times a week (on Monday, Wednesday and Friday) for 4 weeks. Lysholm knees scoring scale (LKSS) was used to evaluate the knee joint function before and after treatment, and the content of transforming growth factor-β1 (TGF-β1) in the joint effusion before and after treatment was determined by enzyme-linked immunosorbent assay (ELISA).@*RESULTS@#Compared before treatment, the total score and each score of LKSS were increased after treatment in the three groups (all <0.05). The improvements of total score, pain score, instability score, swelling score of LKSS in the continuous wave group and the dilatational wave group were superior to those in the discontinuous wave group (all <0.05). The content of TGF-β1 in the joint effusion in each group was increased after treatment (<0.05), and the improvement in dilatational wave group was superior to thoes in the continuous wave group and the discontinuous wave group (all <0.05).@*CONCLUSION@#The three different waves of EA could all improve the clinical symptoms of KOA, which may promote cartilage repair by increasing TGF-β1 content. The dilatational wave had the best overall effect, which can be used as a clinical optimal treatment.

The value of cardiopulmonary resuscitation quality index in evaluating the prognosis during cardiopulmonary resuscitation / 中华急诊医学杂志

Objective To explore the timeliness value of cardiopulmonary resuscitation quality index (CQI) in patients' prognostic evaluation during cardiopulmonary resuscitation (CPR).Methods A prospective descriptive study was conducted.According to whether they got return of spontaneously circulation (ROSC) or not,45 patients receiving CPR were divided into the ROSC group and non-ROSC group.The changes of CQI and partial pressure of end-tidal carbon dioxide (PETCO2) during CPR were collected,and were analyzed to valuate the prognosis of patients.Results The initial,end,and average PETCO2 were statistically different between the ROSC group and the non-ROSC group [7.0(3.6,14.6) vs 7.0(3.6,14.6) mmHg;29.5(19.8,35.9) vs 4.0(2.3,10.2)mmHg;and 22.2(11.8,36.3) vs 4.0(2.5,9.0) mmHg,respectively;P＜0.05],and the end CQI was statistically different between the two groups (59.6±8.9 vs 34.8±5.2,P＜0.05).The CQI differences between the two groups initiated at 11 min after CPR,and stopped at 29 min after CPR.The optimal cut-offpoint of terminal CQI and PETCO2 for prognostic was 33.2 and 16.1 mmHg respectively,and there was a statistically difference in the area under the curve between them (P＜0.05).Conclusions During CPR,both CQI and PETCO2 can be used to evaluate the prognosis,and CQI is more capable of predicting in the late stage of CPR.

Construction of an Electrocardiogram Database Including 12 Lead Waveforms / 대한의료정보학회지

OBJECTIVES: Electrocardiogram (ECG) data are important for the study of cardiovascular disease and adverse drug reactions. Although the development of analytical techniques such as machine learning has improved our ability to extract useful information from ECGs, there is a lack of easily available ECG data for research purposes. We previously published an article on a database of ECG parameters and related clinical data (ECG-ViEW), which we have now updated with additional 12-lead waveform information. METHODS: All ECGs stored in portable document format (PDF) were collected from a tertiary teaching hospital in Korea over a 23-year study period. We developed software which can extract all ECG parameters and waveform information from the ECG reports in PDF format and stored it in a database (meta data) and a text file (raw waveform). RESULTS: Our database includes all parameters (ventricular rate, PR interval, QRS duration, QT/QTc interval, P-R-T axes, and interpretations) and 12-lead waveforms (for leads I, II, III, aVR, aVL, aVF, V1, V2, V3, V4, V5, and V6) from 1,039,550 ECGs (from 447,445 patients). Demographics, drug exposure data, diagnosis history, and laboratory test results (serum calcium, magnesium, and potassium levels) were also extracted from electronic medical records and linked to the ECG information. CONCLUSIONS: Electrocardiogram information that includes 12 lead waveforms was extracted and transformed into a form that can be analyzed. The description and programming codes in this case report could be a reference for other researchers to build ECG databases using their own local ECG repository.

Study on Force Mechanism for Therapeutic Effect of Pushing Manipulation with One-Finger Meditation Base on Similarity Analysis of Force and Waveform / 中国结合医学杂志

<p><b>OBJECTIVE</b>To reveal the force mechanism for therapeutic effect of pushing manipulation with one-finger meditation.</p><p><b>METHODS</b>A total of 15 participants were recruited in this study and assigned to an expert group, a skilled group and a novice group, with 5 participants in each group. Mechanical signals were collected from a biomechanical testing platform, and these data were further observed via similarity analysis and cluster analysis.</p><p><b>RESULTS</b>Comparing the force waveforms of manipulation revealed that the manipulation forces were similar between the expert group and the skilled group (P>0.05). The mean value of vertical force was 9.8 N, and 95% CI rang from 6.37 to 14.70 N, but there were significant differences compared with the novice group (P<0.05). The result of overall similarity coefficient cluster analysis showed that two kinds of manipulation forces curves were existed between the expert group and the skilled group.</p><p><b>CONCLUSION</b>Pushing manipulation with one-finger meditation is a kind of light stimulation manipulation on the acupoint, and force characteristics of double waveforms continuously alternated during manual operation.</p>

Aplicaciones clínicas del análisis acústico de la voz / Clinical applications of acoustic voice analysis

El análisis acústico de la voz es un método de evaluación vocal objetivo y no invasivo, utilizado con fines diagnósticos, terapéuticos e investigativos. Utiliza registros acústicos obtenidos directamente de la voz del paciente mediante el uso de un micrófono profesional. Existe una gran variedad de programas y métodos de graficación disponibles, que favorecen la versatilidad y especificidad del proceso. Esta revisión muestra los métodos de graficación de la voz más utilizados.

The acoustic voice analysis is an objective and non invasive vocal assessment method, used for voice diagnosis, therapy and research. It uses acoustic records obtained from the patient's voice using professional microphones. There is a variety of softwares and graphing programs available that allows process versatility and specificity. This review presents the most utilized methods of voice graphing.

Effect of electroacupuncture pretreatment with different waveforms on septic brain injury in rats / 临床麻醉学杂志

Objective To observe the effects of three pretreatments of electroacupuncture with different waveforms for septic brain injury in rats, and to explore the optimal waveform. Methods Eighty male Sprague-Dawley rats were divided randomly into five groups (n = 16):sham group,cecal ligation and puncture group (group CLP),continuous wave group (group CW),dilata-tional wave group (group DW)and intermittent wave group (group IW).A rat sepsis model was pre-pared by cecal ligation and puncture.Brain water content was detected.Tumor necrosis factor (TNF)-α,interleukin(IL)-6,malondialdehyde (MDA)and superoxide dismutase (SOD)in serum and frontal cortex were detected 48 h after sham or CLP operation.Pathological changes of frontal cortex,ex-pression of Toll-like receptor-4 (TLR4),and apoptosis of nerve cells were observed by hematoxylin and eosin staining (H&E),immunohistochemistry and TUNEL assay,respectively.Results Com-pared with the sham group,encephaledema,as well as brain injury and neuron apoptosis increased in group CLP (P <0.05).Concentrations of tumor necrosis factor-α,interleukin-6,and malondialdehyde in serum and frontal cortex significantly increased,and the activities of superoxide dismutase significantly de-creased (P < 0.05 ).The expression of TLR4 significantly increased (P < 0.05 ).Compared with group CLP,the aforementioned indicators in the continuous,dilatational,and intermittent wave groups significantly improved (P < 0.05 ).Compared among the electroacupunctured groups,the effect of dilatational wave was the most significant,followed by intermittent wave,and continuous wave was the least one (P <0.05).Conclusion EA pretreatment with different waveforms at Baihui and Tsusanli acupoints could reduce the septic brain injury,and DW might be the best one.The mechanism might be related with the inhibition of inflammation and oxidative stress response and the decrease in nerve cell apoptosis.

Value of Doppler ultrasound in monitoring velocity waveforms in the fetal main pulmonary artery in patients with early onset severe preeclampsia / 中华超声影像学杂志

Objective To explore the change of Doppler velocity waveforms in the fetal main pulmonary artery in patients with early onset severe preeclampsia and to assess its value in fetal lung maturity.Methods A prospective study was conducted to analyze fetal main pulmonary artery velocity waveforms parameters including acceleration time(AT),ejection time(ET),acceleration time/ejection time (AT/ET),peak systolic velocity (PSV) in 30 cases of pregnant women with early onset severe preeclampsia.According to neonatal outcome,these cases were divided into respiratory distress syndrome (RDS) group (18 cases) and non-RDS group (12 cases).Each group was compared with 54 cases and 36 cases that were normal and had corresponding gestational age separately.Doppler parameters were compared between these two groups and their corresponding normal control groups.Results Gestational age at sonographic examination,gestational age at delivery and birth weight of neonates in RDS group were significantly lower than those in non-RDS group(all P ＜0.001).The value of AT,ET,AT/ET,PSV were lower in RDS group than those in gestational age-matched control group(all P ＜0.05),while there were no significant difference between non-RDS group and gestational age-matched control group(all P ＞ 0.05).Conclusions Doppler ultrasound monitoring fetal main pulmonary artery velocity waveforms to evaluate fetal lung maturity in patients with early onset severe preeclampsia has clinical application value.

Determination of optimal threshold for hepatic artery stenosis on Doppler ultrasonography and its effect for clinical decision of treatment for patients with tardus parvus waveform after liver transplantation / 器官移植

Objective To analyze the optimal threshold of Doppler ultrasonography(DUS)in the diagnosis of hepatic artery stenosis(HAS)after liver transplantation and propose the diagnostic criteria of CT angiography(CTA) or digital subtraction angiography(DSA)for patients with tardus parvus waveform(TPW)in combination with liver dysfunction. Methods Clinical data of 171 patients undergoing liver transplantation, postoperative conventional DUS, liver function test, CTA or DSA were collected. The optimal threshold of resistance index(RI)and systolic acceleration time (SAT)for the diagnosis of HAS were determined by multi-level likelihood ratio(MLR). Different diagnostic criteria were established and the diagnostic efficacy was statistical y compared. Positive TPW was defined as the diagnostic criterion with low confidence, positive TPW+liver dysfunction as the moderate confidences, and positive TPW+liver dysfunction or positive TPW+optimal threshold as the high confidence. Results MLR revealed that RI<0.4 and SAT>0.12 s were the optimal threshold for the diagnosis of HAS. The specificity of diagnostic criteria with moderate and high confidence was significantly higher compared with that of the low confidence(P<0.05). Moreover, the false-positive rate was significantly decreased(P<0.05). The sensitivity of diagnostic criterion with moderate confidence was significantly lower than those of low and high confidence(both P<0.05), whereas the sensitivity did not significantly differ between the diagnostic criteria with low and high confidence(P>0.05). Conclusions For patients with positive TPW detected by DUS after liver transplantation, the optimal threshold of diagnostic criteria combined with liver dysfunction contribute to appropriate clinical decision-making for clinicians.

Reversed-Phase High Performance Liquid Chromatography Coupled with Pulsed Electrochemical Detection for the Determination of Related Substances in Netilmicin Sulfate Injection / 中国药学杂志

OBJECTIVE: To establish an improved reversed-phase high performance liquid chromatography method coupled with pulsed electrochemical detection for determining the related substances of netilmicin sulfate injection. METHODS: Agilent Proshell 120 SB-C18 column (4.6 mm×150 mm, 2.7 μm)and gradient elution were used. Mobile phase A was 0.2 mol·L-1 trifluoroacetic acid in 0.1 mol·L-1 sodium hydroxide solution-acetonitrile (97:3), mobile phase B was 0.1% pentafluoropropionic acid-acetonitrile (97:3), and the flow rate was 0.8 mL·min-1. A pulsed electrochemical detector was adopted, and the temperatures of detector and column were kept at 35℃. The working electrode was a gold electrode with diameter of 3 mm and a quadruple-potential waveform (QPW)was selected as detection waveform. The injection volume was 25 μL. NaOH solution of 0.8 mol·L-1 was added post-column at a flow rate of 0.3 mL·min-1. RESULTS: A total of 28 impurities could be detected and effective separation was achieved in the typical sample and most of which could not be separated in the method of Ch.P 2015. The linearity of the calibration curve for netilmicin ranged from 0.25 to 15 μg·mL-1 with a coefficient of determination equal to 0.999 1. The LOD and LOQ of netilmicin were found to be 0.25 ng and 1.25 ng, respectively. The repeatability RSD(n=6) of the single largest impurity and total impurities were 0.9% and 0.8%, respectively. The sample solution was stable within 24 h. CONCLUSION: Compared with previously published investigations, the improved method shows higher sensitivity, better separation ability and good reproducibility, especially for differentiating the origin of bulk drug for netilmicin sulfate injection, thus is more suitable for the determination of related substances of netilmicin sulfate injection.

Detection of the early keratoconus based on corneal biomechanical properties in the refractive surgery candidates.

Context: Subclinical keratoconus is contraindication to refractive surgery. The currently used methods of preoperative screening do not always allow differentiating between healthy eyes and those with subclinical keratoconus. Aim: To evaluate biomechanical parameters of the cornea, waveform score (WS), and intraocular pressure (IOP) as potentially useful adjuncts to the diagnostic algorithm for precise detection of the early keratoconus stages and selection of refractive surgery candidates. Settings and Design: Department of Ophthalmology and prospective cross‑sectional study. Patients and Methods: Patients enrolled in the study were diagnosed with refractive disorders. We assessed parameters of corneal biomechanics such as corneal hysteresis (CH), corneal resistance factor (CRF), Goldman‑correlated IOP (IOPg), corneal compensated IOP, WS, and keratoconus match index (KMI). They were classified into one of three groups based on the predefined KMI range: Group 1 (from 0.352 to 0.757) – 45 eyes, Group 2 (from −0.08 to 0.313) – 52 eyes, and Group 0 ‑ control group (from 0.761 to 1.642) – 80 eyes. Results: In both study groups, IOPg, CRF, and CH were decreased when compared to control (P < 0.0001). In control group, there was positive correlation between CH and KMI (P < 0.05), with no correlations in any of the two study groups. CRF correlated positively with KMI in control (P < 0.0001) and in Group 2 (P < 0.05). Conclusions: CH and CRF, together with WS and IOPg, consist a clinically useful adjunct to detect subclinical keratoconus in patients referred for refractive surgery when based on KMI staging.

Reference value range of pulse oximetry plethysmographic waveform parameters in the normal adults / 中华急诊医学杂志

Objective To Pulse oximetry saturation has been wildly used clinically.It has been reported that pulse oximetry plethysmographic waveform (POP) reflected the peripheral tissue perfusion.In this study,we parameterized POP,observed the value of POP parameters in normal adults,and established the normal reference value range.Methods A multi-center prospective descriptive study.Total of 1 019 adult volunteers with normovolemia from 7 cities were enrolled in this study.Sex,age,height,weight and pulse oximetry data in awake and spontaneous breathing under in quiet conditions in the room temperature were collected.POP parameters and perfusion index were analyzed using MATLAB 2012a software.The normal reference value ranges of POP parameters,including the amplitude of POP (Amp) and the area under the curve of POP (AUC),were formulated.Results Statistical differences of POP parameters were detected between men and women in the normal adult.The 95％ confidence reference value of POP parameters in normal population was as follows:Amp (104.8-2298.7) PVA and AUC (3265.8-6028.5) PVPGin total,Amp (129.4-2433.6) PVA and AUC (3319.0-5862.2) PVPG in male;Amp (89.5-2138.2) PVA and AUC (3163.9-5929.9) PVPG in female.Conclusions POP,including the amplitude of POP (Amp) and the area under the curve of POP (AUC),had normal reference value ranges in normal adults.