Paired Data Points Research Articles

Human ophthalmic artery as a sensor for non-invasive intracranial pressure monitoring: numerical modeling and in vivo pilot study

Intracranial pressure (ICP) monitoring is important in managing neurosurgical, neurological, and ophthalmological patients with open-angle glaucoma. Non-invasive two-depth transcranial Doppler (TCD) technique is used in a novel method for ICP snapshot measurement that has been previously investigated prospectively, and the results showed clinically acceptable accuracy and precision. The aim of this study was to investigate possibility of using the ophthalmic artery (OA) as a pressure sensor for continuous ICP monitoring. First, numerical modeling was done to investigate the possibility, and then a pilot clinical study was conducted to compare two-depth TCD-based non-invasive ICP monitoring data with readings from an invasive Codman ICP microsensor from patients with severe traumatic brain injury. The numerical modeling showed that the systematic error of non-invasive ICP monitoring was < 1.0 mmHg after eliminating the intraorbital and blood pressure gradient. In a clinical study, a total of 1928 paired data points were collected, and the extreme data points of measured differences between invasive and non-invasive ICP were − 3.94 and 4.68 mmHg (95% CI − 2.55 to 2.72). The total mean and SD were 0.086 ± 1.34 mmHg, and the correlation coefficient was 0.94. The results show that the OA can be used as a linear natural pressure sensor and that it could potentially be possible to monitor the ICP for up to 1 h without recalibration.

Neurophysiological validation of simultaneous intrinsic and reflexive joint impedance estimates

BackgroundPeople with brain or neural injuries, such as cerebral palsy or spinal cord injury, commonly have joint hyper-resistance. Diagnosis and treatment of joint hyper-resistance is challenging due to a mix of tonic and phasic contributions. The parallel-cascade (PC) system identification technique offers a potential solution to disentangle the intrinsic (tonic) and reflexive (phasic) contributions to joint impedance, i.e. resistance. However, a simultaneous neurophysiological validation of both intrinsic and reflexive joint impedances is lacking. This simultaneous validation is important given the mix of tonic and phasic contributions to joint hyper-resistance. Therefore, the main goal of this paper is to perform a group-level neurophysiological validation of the PC system identification technique using electromyography (EMG) measurements.MethodsTen healthy people participated in the study. Perturbations were applied to the ankle joint to elicit reflexes and allow for system identification. Participants completed 20 hold periods of 60 seconds, assumed to have constant joint impedance, with varying magnitudes of intrinsic and reflexive joint impedances across periods. Each hold period provided a paired data point between the PC-based estimates and neurophysiological measures, i.e. between intrinsic stiffness and background EMG, and between reflexive gain and reflex EMG.ResultsThe intrinsic paired data points, with all subjects combined, were strongly correlated, with a range of r = [0.87 0.91] in both ankle plantarflexors and dorsiflexors. The reflexive paired data points were moderately correlated, with r = [0.64 0.69] in the ankle plantarflexors only.ConclusionAn agreement with the neurophysiological basis on which PC algorithms are built is necessary to support its clinical application in people with joint hyper-resistance. Our results show this agreement for the PC system identification technique on group-level. Consequently, these results show the validity of the use of the technique for the integrated assessment and training of people with joint hyper-resistance in clinical practice.

Handling Incomplete Data with Regression Imputation

Regression analysis is widely used in various fields due to easy-to-understand. One of purposes of regression analysis is to predict the response variable using the predictor variables. Unfortunately, in real cases, some values may be missing. This circumstance will produce large error, indeed, poor prediction. Missing value lead us to trade-off remove the paired data points or replace. The purpose of this study was to estimate the missing value with regression imputation. This study conducted two scenarios of amount of missing values, 10% and 15%. The study results showed that the higher of amount of missing values, the higher the value of MSE was. The first section in your paper.

Measuring wet bulb globe temperatures at point-of-exertion in worldwide UK military settings: a longitudinal observational study determining the accuracy of a portable WBGT monitor

IntroductionHeat illness among the UK Armed Forces is usually exertional, and therefore preventable, yet the incidence has not reduced since 2011. JSP 539 explicitly states that wet bulb globe temperature...

Dynamic Light Scattering: A New Noninvasive Technology for Neonatal Heart Rate Monitoring

Background: Heart rate (HR) detection in premature infants using electrocardiography (ECG) is challenging due to a low signal amplitude and the fragility of the premature skin. Recently, the dynamic light scattering (DLS) technique has been miniaturized, allowing noninvasive HR measurements with a single sensor. Objective: The aim was to determine the accuracy of DLS for HR measurement in infants, compared to ECG-derived HR. Methods: Stable infants with a gestational age of ≥26 weeks, monitored with ECG, were eligible for inclusion. HR was measured with the DLS sensor at 5 different sites for 15 min each. We recorded every 10th second of the DLS-derived HR and the DLS signal-to-noise ratio (SNR), and the ECG-derived HR was extracted for analysis. Patients were randomly divided into 2 groups. In the first group, the optimal SNR cut-off value was determined and then applied to the second group to assess agreement. Results: HR measurements from 31 infants were analyzed. ECG-DLS paired data points were collected at the forehead, an upper extremity, the thorax, a lower extremity, and the abdomen. When applying the international accuracy standard for HR detection, DLS accuracy in the first group (n = 15) was optimal at the forehead (SNR cut-off 1.66). Application of this cut-off to the second group (n = 16) showed good agreement between DLS-derived HR and ECG-derived HR (bias –0.73 bpm; 95% limits of agreement –15.46 and 14.00 bpm) at the forehead with approximately 80% (i.e., 1,066/1,310) of all data pairs remaining. Conclusion: The investigated DLS sensor was sensitive to movement, overall providing less accurate HR measurements than ECG and pulse oximetry. In this study population, specific measurement sites provided excellent signal quality and good agreement with ECG-derived HR.

Ecological momentary assessment of mood and physical activity in people with depression

Background: This study aimed to examine temporal associations between physical activity and subsequent mood in people with moderate to severe depression. Methods: The study used ecological momentary assessment to associate mood, measured via text messaging twice daily for five days, using a 10-point Likert scale, with objectively measured physical activity (accelerometer data) in people with moderate-to-severe depression. Multilevel regression models were used to explore the relationship between physical activity undertaken at different intensities over the previous one and three hours, and subsequent affect score. A total of 388 paired data points were collected from 43 participants. Results: There was no association between minutes of moderate-vigorous physical activity in the previous hour and subsequent affect score (which we had hypothesised). However, exploratory analyses found a significant relationship between affect and combined physical activity in the previous hour (β1 coefficient = 0.023, p = 0.037). Limitations: Periods of moderate-vigorous activity were infrequent, reducing the statistical power for analysing associations with this intensity of activity. Only one dimension of mood was sampled. Conclusions: The data suggest that, in people with moderate-to-severe depression, time spent engaging in any intensity of physical activity was significantly associated with subsequent mood. Further research is needed to more clearly define the dynamics of the relationship between physical activity and low mood. This will aid identification of optimal prescription criteria for physical activity in people with depression.

Agreement Between Arterial Carbon Dioxide Levels With End-Tidal Carbon Dioxide Levels and Associated Factors in Children Hospitalized With Traumatic Brain Injury

Alterations in the partial pressure of carbon dioxide, arterial (Paco2) can affect cerebral perfusion after traumatic brain injury. End-tidal carbon dioxide (EtCO2) monitoring is a noninvasive tool used to estimate Paco2 values. To examine the agreement between Paco2 and EtCO2 and associated factors in children with traumatic brain injury. A secondary analysis was conducted using data from a prospective cohort study of 137 patients younger than 18 years with traumatic brain injury who were admitted to the pediatric intensive care unit of a level I trauma center between May 1, 2011, and July 31, 2017. Analysis was performed from December 17, 2018, to January 10, 2019. The closest EtCO2 value obtained within 30 minutes of a Paco2 value and the closest systolic blood pressure value obtained within 60 minutes prior to a Paco2 value during the first 24 hours after admission were recorded. The main outcome of Paco2-EtCO2 agreement was defined as Paco2 between 0 and 5 mm Hg greater than the paired EtCO2 value, and it was determined using Bland-Altman analysis, Passing and Bablok regression, and the Pearson correlation coefficient. Multivariable regression models determined which factors were associated with agreement. The analysis included 137 patients (34 girls and 103 boys; mean [SD] age, 10.0 [6.3] years) and 445 paired Paco2-EtCO2 data points. On average, Paco2 was 2.7 mm Hg (95% limits of agreement, -11.3 to 16.7) higher than EtCO2. Overall, 187 of all Paco2-EtCO2 pairs (42.0%) agreed. There was larger variation in the Paco2-EtCO2 difference during the first 8 hours compared with 9 to 24 hours after admission to the pediatric intensive care unit. Development of pediatric acute respiratory distress syndrome within 24 hours of admission was associated with a lower likelihood of Paco2-EtCO2 agreement (adjusted odds ratio, 0.20; 95% CI, 0.08-0.51) compared with no development of pediatric acute respiratory distress syndrome. A diagnosis of pediatric acute respiratory distress syndrome 1 to 7 days after admission was associated with a larger first-day Paco2-EtCO2 difference compared with those who never developed pediatric acute respiratory distress syndrome (mean [SD] difference, 4.48 [3.70] vs 0.46 [5.50] mm Hg). In this study of pediatric traumatic brain injury, Paco2-EtCO2 agreement was low, especially among patients with pediatric acute respiratory distress syndrome. Low Paco2-EtCO2 agreement early in hospitalization may be associated with future development of pediatric acute respiratory distress syndrome. Data on EtCO2 should not be substituted for data on Paco2 during the first 24 hours.

The perfusion index measured by the pulse oximeter affects the agreement between ClearSight and the arterial catheter-based blood pressures: A prospective observational study

BackgroundClearSight is a noninvasive arterial blood pressure monitor, but it remains unknown whether it is affected by the state of perfusion to the fingers. We investigated whether the lower perfusion index (PI) measured with a pulse oximeter, which reflects finger perfusion, would affect the agreement between arterial pressures measured with ClearSight versus those obtained with an arterial catheter.MethodsPaired arterial pressure data (ClearSight and arterial catheter-based pressures) and PI values were prospectively obtained from 30 patients undergoing major abdominal surgery. The primary outcome was standard deviation (SD) of the bias (precision) of blood pressure between ClearSight and arterial catheter. The ratio of the adjusted SD of the bias between PI≤1 and PI>1 was calculated using the linear mixed-effects model. The secondary outcomes were the bias and the limits of agreement (LOA) between the two devices (repeated measures Bland-Altman analysis).ResultsWe analyzed 6312 paired data points. The adjusted SD of bias in PI ≤1 compared with those in PI >1 was 1.4-fold (95% confidence interval: 1.3- to 1.4-fold) for systolic arterial pressure, 1.5-fold (95% confidence interval: 1.3- to 1.6-fold) for diastolic arterial pressure, and 1.3-fold (95% confidence interval: 1.2- to 1.5-fold) for mean arterial pressure. The bias (LOA) were as follows: systolic arterial pressure in the PI ≤1 and PI >1 groups, -3.5 (-35.4 to 28.4) mmHg and 2.2 (-19.9 to 24.3) mmHg, respectively; diastolic arterial pressure in the PI ≤1 and PI >1 groups, 13.1 (-5.1 to 31.3) mmHg and 9.0, (-2.6 to 20.6) mmHg, respectively; and mean arterial pressure in the PI ≤1 and PI >1 groups, 8.7 (-11.3 to 28.7) mmHg and 7.6 (-6.2 to 21.3) mmHg, respectively.ConclusionsPI ≤1 was associated with a large SD of the bias between the devices. The PI value could be a real-time indicator of ClearSight precision.

Validation of Noninvasive Absolute Intracranial Pressure Measurements in Traumatic Brain Injury and Intracranial Hemorrhage.

Increased intracranial pressure (ICP) causes secondary damage in traumatic brain injury (TBI), and intracranial hemorrhage (ICH). Current methods of ICP monitoring require surgery and carry risks of complications. To validate a new instrument for noninvasive ICP measurement by comparing values obtained from noninvasive measurements to those from commercial implantable devices through this pilot study. The ophthalmic artery (OA) served as a natural ICP sensor. ICP measurements obtained using noninvasive, self-calibrating device utilizing Doppler ultrasound to evaluate OA flow were compared to standard implantable ICP measurement probes. A total of 78 simultaneous, paired, invasive, and noninvasive ICP measurements were obtained in 11 ICU patients over a 17-mo period with the diagnosis of TBI, SAH, or ICH. A total of 24 paired data points were initially excluded because of questions about data independence. Analysis of variance was performed first on the 54 remaining data points and then on the entire set of 78 data points. There was no difference between the 2 groups nor was there any correlation between type of sensor and the patient (F[10, 43] = 1.516, P = .167), or the accuracy and precision of noninvasive ICP measurements (F[1, 43] = 0.511, P = .479). Accuracy was [-1.130; 0.539] mm Hg (CL = 95%). Patient-specific calibration was not needed. Standard deviation (precision) was [1.632; 2.396] mm Hg (CL = 95%). No adverse events were encountered. This pilot study revealed no significant differences between invasive and noninvasive ICP measurements (P < .05), suggesting that noninvasive ICP measurements obtained by this method are comparable and reliable.

Circadian rest-activity rhythm as an objective biomarker of patient-reported outcomes in patients with advanced cancer.

BackgroundPsychosocial symptoms often cluster together, are refractory to treatment, and impair health‐related quality of life (HR‐QoL) in cancer patients. The contribution of circadian rhythm alterations to systemic symptoms has been overlooked in cancer, despite a causal link shown under jet lag and shift work conditions. We investigated whether the circadian rest‐activity rhythm provides a reliable and objective estimate of the most frequent patient‐reported outcome measures (PROMs).MethodsTwo datasets were used, each involving concomitant 3‐day time series of wrist actigraphy and HR‐QoL questionnaires: EORTC QLQ‐C30 was completed once by 237 patients with metastatic colorectal cancer; MD Anderson Symptom Inventory (MDASI) was completed daily by 31 patients with advanced cancer on continuous actigraphy monitoring, providing 1015 paired data points. Circadian function was assessed using the clinically validated dichotomy index I < O. Nonparametric tests compared PROMs and I < O. Effect sizes were computed. Sensitivity subgroup and temporal dynamics analyses were also performed.Results I < O values were significantly lower with increasing symptom severity and worsening HR‐QoL domains. Fatigue and anorexia were worse in patients with circadian disruption. The differences were both statistically and clinically significant (P < 0.001; d ≥ 0.33). Physical and social functioning, and global quality/enjoyment of life were significantly better in patients with robust circadian rhythm (P < 0.001; d ≥ 0.26). Sensitivity analyses validated these findings.ConclusionObjectively determined circadian disruption was consistently and robustly associated with clinically meaningfully severe fatigue, anorexia, and interference with physical and social functioning. This supports an important role of the circadian system in the determination of cancer patients’ HR‐QoL and symptoms that deserves therapeutic exploitation.

Significant Correlation between Regional Tissue Oxygen Saturation and Vital Signs of Critically Ill Infants.

Near-infrared spectroscopy (NIRS) has been used to non-invasively measure specific tissue oxygen saturation (StO2) continuously. Cerebral autoregulation status can be derived from NIRS and arterial blood pressure. The relationship of both cerebral and somatic StO2, fractional tissue oxygen extraction (FTOE), and cerebro-splanchnic oxygenation ratio (CSOR) with measured vital sign parameters for Neonatal Intensive Care Unit (NICU) patients has not been well studied. The aims of this study are to determine if significant relationships of brain and somatic StO2, brain and somatic FTOE, and CSOR parameters with vital signs for neonates exist and assess relationship between pressure passivity index, cerebral autoregulation, and mean blood pressure (MBP). Neonates weighing < 5 kg, preferentially with an arterial catheter, were enrolled in the study. FORE-SIGHT Elite (CASMedical Systems, Inc., Branford, CT, USA) cerebral and somatic NIRS sensors were placed over the abdominal right upper quadrant and right frontal-temporal area of the forehead for 24 h. Vital signs including arterial MBP were recorded simultaneously from the patients' bedside monitor. Data were averaged into 60 s windows and analyzed using linear regression. Results were stratified by gestational age (GA), birth weight (BW), and presence of brain abnormality. Data were obtained from 27 subjects (GA 22.2-42 weeks). Two subjects did not have an arterial line, thus they were not included in the MBP measurements. There were ~28,000-31,000 paired data points per comparison. Significant positive and negative correlations (p value < 0.0001) were noted between NIRS parameters and vital signs. When stratified by BW, there was a positive correlation between brain StO2 (StO2B) and MBP in the <1,500 g BW group (r = 0.193) and a negative correlation in >1,500 g group (r = 0.057). Brain and somatic FTOE in <1,500 g BW revealed a negative correlation with MBP (r = 0.172 and r = 0.086, respectively). In patients with an abnormal brain scan, a positive correlation was noted between StO2B and MBP (r = 0.354), and a negative correlation was noted between FTOE-B and MBP (r = 0.305). Generated pressure passive index plots suggested good cerebral autoregulation at low normal MBP ranges for lower weight and GA subjects. There is a significant correlation between cerebral and somatic StO2 and FTOE with measured vital sign parameters in NICU patients.

Utility of non-invasive haemoglobin monitoring in oncosurgery patients.

Background and Aims:Oncosurgeries may incur massive blood loss demanding frequent blood sampling to assess blood loss and the need for intraoperative blood transfusions. Accuracy of non-invasive spectrophotometric haemoglobin (hereafter to be referred as SpHb) monitoring has been studied in various perioperative settings. The intraoperative use of Radical-7®, Masimo Corp., (Radical-7®) for SpHb monitoring may be useful during cancer surgery. The aim of this study is to evaluate the intraoperative utility of SpHb monitoring by the Radical-7® to guide intraoperative transfusion in oncosurgeries.Methods:Fifty adult patients, undergoing oncosurgery with anticipated blood loss of more than 20% of blood volume, were selected. Continuous SpHb monitoring was performed intraoperatively and blood transfusion was based on SpHb values. Simultaneous laboratory haemoglobin (LabHb) samples were taken for validation. The accuracy of intraoperative blood transfusions based on SpHb was analysed using Error Grid Analysis. Paired measurements of SpHb and LabHb were compared using Bland–Altman plot analysis.Results:There were 66 paired data points for blood transfusion from fifty patients with a correlation of 73% (P < 0.001) between SpHb and LabHb. In the Bland–Altman analysis, the bias was − 0.313 g/dl with ~ 95% of values within the limits of agreement of 1.81 g/dl to −2.44 g/dl. In the Error Grid Analysis, most data points were in the least error zone (Zone A).Conclusion:The Radical-7® has the advantage of providing SpHb value continuously to take prompt decision regarding blood transfusion intraoperatively.

Blood volume measured by ultrasound and radioisotope dilution in critically ill subjects

BackgroundAccurate bedside assessment of circulating blood volume (BV) continues to challenge clinicians in their attempt to implement goal-directed therapy in the critically ill subject. The aim of this investigation was to comparatively evaluate BV measurements obtained by ultrasound and radioisotope dilution methodologies in adult subjects admitted to a surgical intensive care unit. Materials and methodsFifty subjects with concurrent central venous catheters and peripheral arterial lines underwent measurement of BV using both ultrasound and radioisotope dilution (BV-RD) methods. The ultrasound dilution method was performed using a 30-mL injectate (BV-UD30) and a 60-mL injectate (BV-UD60) of isotonic saline. ResultsThere were 24 paired data points for the BV-UD30 and 40 paired data points for the BV-UD60 measurements. Spearman's rank-order correlation demonstrated a positive relationship comparing both the BV-UD30 (r = 0.46, P = 0.0249) and the BV-UD60 (r = 0.80, P < 0.0001) to values obtained by radioisotope measurements. Bland–Altman analysis showed a mean bias of 1329 mL with limits of agreement (LOA) ± 2559 mL comparing BV-RD and BV-UD30, and a mean bias of 62 mL with LOA ±1353 mL for BV-RD and BV-UD60. ConclusionsThis preliminary investigation shows that the BV-UD60 had better agreement with BV-RD, compared with the BV-UD30, but its utility appears limited by a large LOA. As this technology continues to evolve, the ultrasound dilution approach may potentially become a feasible means to calculate BV in critically ill surgical subjects.

Evaluation of Reliability of MYZONE MZ-3 Heart Rate Monitor: A Study for the Future of Telephysiotherapy for Preoperative Prehabilitation in Cancer Patients.

There are a number of commercially available heart rate (HR) monitors on the market. The reliability of these monitors has had varying results. To the best of our knowledge, there are no telemonitoring services utilizing these devices for perioperative prehabilitation services for patients undergoing major surgery. The goal of this study is to pilot the MYZONE® MZ-3 HR monitor to assess its level of reliability to provide a feasible telephysiotherapy prehabilitation service through prescription-based exercise programs to patients presenting for major cancer surgery within our leading oncological health service. Paired HR data from each participant were captured and analyzed using a Bland-Altman plot. Seven healthy participants were included in the study with a total number of paired HR data points of 1,928. The bias (mean difference) between electrocardiogram and the MYZONE MZ-3 was 0.4 beats per minute (bpm) with an adjusted 95% limits of agreement of -4.5 to 5.3 bpm. The commercially available MYZONE MZ-3 HR monitor is a reliable tool for delivering telephysiotherapy to patients undergoing major cancer surgery. Further studies are needed to validate its use in this setting.

Can intracranial pressure be measured non-invasively bedside using a two-depth Doppler-technique?

Measurement of intracranial pressure (ICP) is necessary in many neurological and neurosurgical diseases. To avoid lumbar puncture or intracranial ICP probes, non-invasive ICP techniques are becoming popular. A recently developed technology uses two-depth Doppler to compare arterial pulsations in the intra- and extra-cranial segments of the ophthalmic artery for non-invasive estimation of ICP. The aim of this study was to investigate how well non-invasively-measured ICP and invasively-measured cerebrospinal fluid (CSF) pressure correlate. We performed multiple measurements over a wide ICP span in eighteen elderly patients with communicating hydrocephalus. As a reference, an automatic CSF infusion apparatus was connected to the lumbar space. Ringer's solution was used to create elevation to pre-defined ICP levels. Bench tests of the infusion apparatus showed a random error (95% CI) of less than ±0.9mmHg and a systematic error of less than ±0.5mmHg. Reliable Doppler signals were obtained in 13 (72%) patients. An infusion test could not be performed in one patient. Thus, twelve patients and a total of 61 paired data points were studied. The correlation between invasive and non-invasive ICP measurements was good (R=0.74), and the 95% limits of agreements were -1.4±8.8mmHg. The within-patient correlation varied between 0.47 and 1.00. This non-invasive technique is promising, and these results encourage further development and evaluation before the method can be recommended for use in clinical practice.

Continuous Glucose Monitoring in Patients Undergoing Extracorporeal Ventricular Assist Therapy.

BackgroundDysregulations of blood glucose (BG) are associated with adverse outcome in critical illness; controlling BG to target appears to improve outcome. Since BG-control is challenging in daily intensive care practice BG-control remains poor especially in patients with rapidly fluctuating BG. To improve BG-control and to avoid deleterious hypoglycemia, automated online-measurement tools are advocated. We thus evaluated the point-accuracy of the subcutaneous Sentrino® Continuous Glucose Monitoring System (CGM, Medtronic Diabetes, Northridge, California) in patients undergoing extracorporeal cardiac life support (ECLS) for cardiogenic shock.MethodsManagement of BG was performed according to institute’s standard aiming at BG-levels between 100–145 mg/dl. CGM-values were recorded without taking measures into therapeutic account. Point-accuracy in comparison to intermittent BG-measurement by the ABL-blood-gas analyzer was determined.ResultsCGM (n = 25 patients) correlated significantly with ABL-values (r = 0.733, p<0.001). Mean error from standard was 15.0 mg/dl (11.9%). 44.2% of the readings were outside a 15% range around ABL-values. In one of 635 paired data-points, ABL revealed hypoglycemia (BG 32 mg/dl) whereas CGM did not show hypoglycemic values (132mg/dl).ConclusionsCGM reveals minimally invasive BG-values in critically ill adults with dynamically impaired tissue perfusion. Because of potential deviations from standard, CGM-readings must be interpreted with caution in specific ICU-populations.

Validation of Noninvasive Absolute Intracranial Pressure Measurements in Traumatic Brain Injury and Intracranial Hemorrhage: Preliminary Results

Aim: Increased intracranial pressure (ICP) is considered to be the most important mechanism of secondary brain injury in patients with acute traumatic brain injury (TBI), and intracranial hemorrhage (ICH) including subarachnoid hemorrhage (SAH). Currently, ICP can be measured and registered only using invasive techniques in routine clinical practice. Routine ICP monitoring in terms of intraventricular and intraparenchymal measurements are invasive, require a surgical procedure, and are associated with complications such as infection and intracranial bleedings. The aim of this ongoing study is the validation of noninvasive absolute ICP measurements with standard methods of invasive measurements obtained with intraventricular or intraparenchymal probes. Additionally, the accuracy and precision of noninvasive absolute ICP will be evaluated. Preliminary results are presented. Methods: The noninvasive ICP measurement device used in this study has been developed in the Telematic Science Laboratory at the Kaunas University of Technology, Lithuania. Noninvasive technique for measurement of ICP is based on simultaneously measuring of an ophthalmic artery (OA) blood flow parameters in the intracranial (IOA) and extracranial (EOA) segments of the OA with two-depth transcranial Doppler (TCD) measurements including mechanical head frame for fixation of ultrasonic transducer on the closed eye lid. No individual patient-specific calibration is required. Approval of Swissmedic and our EC was obtained in December 2013. Results: A total of 43 repeatable simultaneous paired noninvasive and invasive ICP measurements in 10 patients admitted with TBI, SAH, or ICH in our ICU. Preliminary results showed an accuracy (systematic error) of noninvasive absolute ICP measurement of 0.64 mm Hg, and a precision (standard deviation of the random error) SD = 1.76 mm Hg. The mean systematic error (0.64 mm Hg) from 43 data points showed a statistically significant evidence. To reach significant evidence > 95%, more paired data points are needed. During our 15 months study period no adverse event was observed. Conclusion: Preliminary results of this study showed that noninvasive transcranial Doppler absolute ICP measurement correlates with standard invasive ICP measurement. This method seems to be safe and reliable. The introduction of this technique is might be promising for the preoperative evaluation of patients presenting with severe stroke and brain tumors.

The relationship between the Bispectral Index (BIS) and the Observer Alertness of Sedation Scale (OASS) scores during propofol sedation with and without ketamine: a randomized, double blinded, placebo controlled clinical trial.

Prior studies have examined the static effect of intravenous ketamine on the BIS Index for sedation but it remains unknown if the BIS Index is a reliable method to track sedation levels in the presence of ketamine. The major objective of the current investigation was to compare the BIS Vista Index ability to track varying depths of sedation as determined by OASS scores in a standardized anesthetic regimen with and without ketamine. The study was a randomized, double blinded clinical trial. Patients undergoing breast surgery under sedation with propofol were randomized to receive ketamine (1.5μgkgmin(-1)) or saline. Infusion data was used to estimate propofol plasma concentrations (Cp). The main outcome of interest was the correlation between the BIS Vista Index with the OASS score. Twenty subjects were recruited and fifteen completed the study. Four hundred fifty-five paired data points were included in the analysis. Model performance (Nagelkerke R(2)) of the multinomial logistic regression model was 0.57 with the c-statistic of 0.87 (95% CI 0.82-0.91). Compared to awake the odds ratio for BIS values predicting moderate sedation in the saline/propofol group 1.19 (95% CI 1.12-1.25) but only 1.06 (95% CI 1.02-1.1) in the ketamine/propofol group (P=0.001). There was no difference in the odds for BIS values to predict deep sedation between groups (P=0.14). The BIS monitor can be used to monitor sedation level even when ketamine is used with propofol as part of the sedation regimen. However, ketamine reduces the value of the BIS in predicting moderate sedation levels.

Continuous Glucose Monitoring in Type 1 Diabetes Pregnancy Shows that Fetal Heart Rate Correlates with Maternal Glycemia.

Much evidence has shown that pregnancies in women with preexisting diabetes are affected by an increased risk of maternal and fetal adverse outcomes, probably linked to poor glycemic control. Despite great progress in medical care, the rate of stillbirths remains much higher in diabetes patients than in the general population. Recent technological advances in the field of glucose monitoring and noninvasive fetal heart rate monitoring made it possible to observe the fetal-maternal dependencies in a continuous manner. Fourteen type 1 diabetes patients were involved into the study and fitted with a blinded continuous glucose monitoring (CGM) recorder. Fetal electrocardiogram data were recorded using the Monica AN24™ device (Monica Healthcare Ltd., Nottingham, United Kingdom), the recordings of which were matched with CGM data. Statistical analysis was performed using a generalized mixed-effect logistic regression to account for individual factors. The mean number of paired data points per patient was 254±106, representing an observation period of 21.2±8.8 h. Mean glycemia equaled 5.64±0.68 mmol/L, and mean fetal heart rate was 135±6 beats/min. Higher glycemia correlated with fetal heart rate (R=0.32; P<0.0001) and was associated with higher odds of the fetus developing small accelerations (odds ratio=1.05; 95% confidence interval, 1.00-1.10; P=0.04). Elevated maternal glycemia of mothers with diabetes is associated with accelerations of fetal heart rate.

Agricultural carbon flux changes driven by intensive plastic greenhouse cultivation in five climatic regions of China

It is still controversial as to whether intensive agriculture increases or decreases carbon emissions compared to conventional farming. Carbon flux changes induced by the conversion of agricultural practices in different climatic regions have long been a scientific focus. As an intensive cultivation practice, vegetable cultivation within plastic greenhouses (PGVC) has been reported to reduce net carbon emissions following the conversion from conventional vegetable cultivation (CVC). However, it remains uncertain to what degree the carbon flux changes following the conversion in different climatic regions. Based on 637 paired soil data points and 189 vegetable data points from five major climatic regions in China, we used a full carbon cycle analysis to estimate the carbon flux changes when converting from CVC to PGVC. Results showed that the conversion reduced net carbon emissions in four climatic regions (middle temperate, warm temperate, south subtropical and north subtropical regions) but increased net carbon emissions in the Tibet Plateau region. This regional variation was attributable to the differences between soil carbon sequestration and fossil fuel emissions. The highest reduction (1.46 Mg Cha−1yr−1) occurred in the middle temperate region while the Tibet Plateau region acted as a net carbon source (−0.24 Mg Cha−1yr−1). This suggests that the conversion can increase carbon benefits within the four climatic regions. PGVC in these regions could be considered as a promising option for carbon-smart intensive agriculture and would be worth expanding in countries with similar weather conditions, to mitigate carbon emissions.