The accuracy of Pleth Variability Index for directed fluid optimization in donors in living donor liver transplantation

Background Fluid management strongly affects hepatic resection and aims to reduce intraoperative bleeding during living donation. The Pleth Variability Index (PVI) is a tool to assess the fluid responsiveness from the pulse oximeter waveform; we evaluated the efficacy and accuracy of finger PVI compared to pulse pressure variation (PPV) from arterial waveform in predicting the fluid response in donor hepatectomy patients with the guide of non-invasive cardiac output (CO) measurements. We recruited forty patients who were candidates for right lobe hepatectomy for liver transplantation under conventional general anesthesia methods. During periods of intraoperative hypovolemia not affected by surgical manipulation, PVI, PPV, and CO were recorded then compared with definitive values after fluid bolus administration of 3–5 ml/kg aiming to give a 10% increase in CO which classified the patients into responders and non-responders. Results Both PPV and PVI showed a significant drop after fluid bolus dose (P < 0.001) leading to an increase of the CO (P < 0.0001), and the area under the curve was 0.934, 0.842 (95% confidence interval, 0.809 to 0.988, 0.692 to 0.938) and the standard error was 0.0336, 0.124, respectively. Pairwise comparison of PPV and PVI showed non-significant predictive value between the two variables (P = 0.4605); the difference between the two areas was 0.0921 (SE 0125 and 95% CI − 0.152 to 0.337). Conclusions PVI is an unreliable indicator for fluid response in low-risk donors undergoing right lobe hepatectomy compared to PPV. We need further studies with unbiased PVI monitors in order to implement a non-invasive and safe method for fluid responsiveness.

The use of oxygen reserve index in one-lung ventilation and its impact on peripheral oxygen saturation, perfusion index and, pleth variability index

Background Our goal is to investigate the use of the oxygen reserve index (ORi) to detect hypoxemia and its relation with parameters such as; peripheral oxygen saturation, perfusion index (PI), and pleth variability index (PVI) during one-lung ventilation (OLV). Methods Fifty patients undergoing general anesthesia and OLV for elective thoracic surgeries were enrolled in an observational cohort study in a tertiary care teaching hospital. All patients required OLV after a left-sided double-lumen tube insertion during intubation. The definition of hypoxemia during OLV is a peripheral oxygen saturation (SpO2) value of less than 95%, while the inspired oxygen fraction (FiO2) is higher than 50% on a pulse oximetry device. ORi, pulse oximetry, PI, and PVI values were measured continuously. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and accuracy were calculated for ORi values equal to zero in different time points during surgery to predict hypoxemia. At Clinicaltrials.gov registry, the Registration ID is NCT05050552. Results Hypoxemia was observed in 19 patients (38%). The accuracy for predicting hypoxemia during anesthesia induction at ORi value equals zero at 5 min after intubation in the supine position (DS5) showed a sensitivity of 92.3% (95% CI 84.9–99.6), specificity of 81.1% (95% CI 70.2–91.9), and an accuracy of 84.0% (95% CI 73.8–94.2). For predicting hypoxemia, ORi equals zero show good sensitivity, specificity, and statistical accuracy values for time points of DS5 until OLV30 where the sensitivity of 43.8%, specificity of 64%, and an accuracy of 56.1% were recorded. ORi and SpO2 correlation was found at DS5, 5 min after lateral position with two-lung ventilation (DL5) and at 10 min after OLV (OLV10) (p = 0.044, p = 0.039, p = 0.011, respectively). Time-dependent correlations also showed that; at a time point of DS5, ORi has a significant negative correlation with PI whereas, no correlations with PVI were noted. Conclusions During the use of OLV for thoracic surgeries, from 5 min after intubation (DS5) up to 30 min after the start of OLV, ORi provides valuable information in predicting hypoxemia defined as SpO2 less than 95% on pulse oximeter at FiO2 higher than 50%.

Spatial temporal analysis for potential wave energy resources in Indonesia

Future energy becomes a concern all over the country. The fossil energy resources are decreasing now, and the exploitation these resources leave behind environmental problems. It was increasing the gas emission of CO2 and affected global warming. Renewable and environmentally friendly energy resource is the right choice to solve the problem. Wave power is one of the marine resources that have an advantage in hight density and continuity. This research aims to investigate the spatial-temporal distribution of wave power potency. This study location between 90°E – 150°E; 15°N – 15°S. We used a hindcast data simulation of WAVEWATCH-III with 0.125° (~14 km) spatial resolution and six-hourly data for 25 years (1991-2015). We determine the potential wave power resources by considering the wave flux, Presence of Exceedance (PE), Coefficient of Variation (Cv), Monthly Variability Index (MV), and Seasonal Variability Index (SV). The result shows that in the open sea, such as the Indian Ocean and Pacific Ocean, contains higher wave power density. The level of stability shows that this area is more stable than the inner sea. The power density changes periodically conducted with the monsoonal cycle. The highest energy flux in the Indian Ocean achieved when Australian monsoon and lowest when Asian monsoon, whereas in the Pacific Ocean, the peak of power density reaches when Asian monsoon onset and the lowest in June-July-August. The most stable level coherent with the highest power density, and the lowest level is in the transition period. Based on this analysis, the most potential areas for wave power development are in Enggano, Lampung, Banten, West Java, Central Java, DIY, East Java until Bali.

The Use of Oxygen Reserve Index in One-Lung Ventilation and Its Impact On Peripheral Oxygen Saturation, Perfusion Index and Pleth Variability Index

Background: Our goal is to investigate the use of the Oxygen Reserve Index (ORi) and its relation with peripheral oxygen saturation, perfusion index (PI), and pleth variability index (PVI) during one-lung ventilation (OLV).Methods: Fifty patients undergoing general anesthesia and OLV for elective thoracic surgeries were enrolled in an observational cohort study in a tertiary care teaching hospital. During general anesthesia induction, propofol, fentanyl, and rocuronium at appropriate doses were administered intravenously. All patients required OLV after a left-sided double-lumen tube insertion during intubation. Hypoxemia during OLV was defined as peripheral oxygen saturation (SpO2) value of less than 95% when the inspired oxygen fraction (FiO2) is above 60% on a pulse oximetry device. ORi, pulse oximetry, PI, and PVI were measured continuously. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and accuracy were calculated for ORi equals zero in different anesthesia time points to predict hypoxemia. At Clinicaltrials.gov registry, the Registration ID is NCT05050552.Results: The accuracy for predicting hypoxemia during anesthesia induction at ORi value equals zero at five minutes after intubation in the supine position (DS5) showed a sensitivity of 92.3% (95% CI 84.9-99.6), specificity of 81.1% (95% CI 70.2-91.9), and an accuracy of 84.0% (95% CI 73.8- 94.2). ORi and SpO2 correlation was found at DS5 (p = 0.044), 5 minutes after lateral position with two-lung ventilation (DL5) (p = 0.039), and at 10 minutes after OLV (OLV10)(p = 0.011).Conclusions: ORi equals zero at the time point of five minutes after tracheal intubation in the supine position (DS5) showed high sensitivity and specificity for predicting hypoxemia at a less than 95% value.

Platelet Variability Index: A measure of platelet count fluctuations in patients with immune thrombocytopenia

Fluctuations in platelet count levels over time may help distinguish immune thrombocytopenia (ITP) from other causes of thrombocytopenia. We derived the platelet variability (PVI) score to capture both the fluctuations in platelet count measurements and the severity of the thrombocytopenia over time. Raw PVI values, ranging from negative (less severe thrombocytopenia and/or low fluctuations) to positive (more severe thrombocytopenia and/or high fluctuations) were converted to an ordinal PVI score, from 0 - 6. We evaluated performance characteristics of the PVI score for consecutive adults with thrombocytopenia from the McMaster ITP Registry. We defined patients with definite ITP as those who achieved a platelet count response after treatment with intravenous immune globulin or high dose corticosteroids; and possible ITP as those who never received ITP treatment or did not respond to treatment. Of 841 thrombocytopenic patients, 104 had definite ITP, 398 had possible ITP, and 339 had non-ITP thrombocytopenia. The median PVI score was 5 (interquartile range [IQR] 5, 6) for definite ITP; 3 (1, 5) for possible ITP; and 0 (0, 2) for non-ITP. A high PVI score correlated with the diagnosis of definite ITP even when calculated at the patient's initial assessment, before any treatment had been administered. Platelet count fluctuations alone contributed to the specificity of the overall PVI score. The PVI score may help clinicians diagnose ITP among patients with thrombocytopenia.

Applicability of the medication level variability index (MLVI) in adult hepatic transplantation and association with graft rejection rates

Introduction: Calculation of the Tacrolimus variation index by using the MLVI (Medication Level Variability Index) is set in pediatric liver transplant patients, and it is useful in controlling treatment adherence by associating MLVI values > 2.5 to acute graft liver rejection. Purpose: To verify the association between MLVI values and rejection in adult liver transplant patients. Methods: A retrospective cohort study including liver transplant patients over 18 years of age from December 2012 to December 2017 using orally tacrolimus. For MLVI calculation, tacrolimus serum level outpatient samples were used after 1 year of transplantation. Results: A total of 125 patients were transplanted, of which 86 met criteria for inclusion in the study. The most frequent reason for transplantation was C virus infection (55.8%, n = 48). Rejection was identified in 18.6% of patients (n = 16). The mean MLVI among rejection and nonrejection patients was 2.5 and 2.1 respectively (RR = 0.95, CI: 0.4-2.1, p = 0.57). The frequency of non-immunological complications was 56.2% (n = 9) in patients with rejection versus 62.8% (n = 44) in patients without rejection, most of them with recurrence of virus C (56,8%, n = 25). Conclusion: Although the mean value of MLVI was higher in patients with rejection, our data showed no statistical difference between both groups, which differs from previous studies in pediatric patients. A higher number of nonimmune complications were observed in patients without rejection. The findings suggest that new MLVI cutoffs should be explored in the adult population.

Brain changes underlying progression of speech motor programming impairment

Aquired apraxia of speech is a disorder that impairs speech production, despite intact peripheral neuromotor function. Its pathomechanism remains to be established. Neurodegenerative lesion models provide an unequalled opportunity to explore the neural correlates of apraxia of speech, which is present in a subset of patients diagnosed with non-semantic variants of primary progressive aphasia. The normalised pairwise variability index, an acoustic measure of speech motor programming, has shown high sensitivity and specificity for apraxia of speech in cross-sectional studies. Here, we aimed to examine the strength of the pairwise variability index and overall word duration (i.e. articulation rate) as markers of progressive motor programming deficits in primary progressive aphasia with apraxia of speech. Seventy-nine individuals diagnosed with primary progressive aphasia (39 with non-fluent variant, 40 with logopenic variant) and 40 matched healthy controls participated. Patients were followed-up annually (range 1–6 years, median number of visits = 2). All participants completed a speech assessment task and a high-resolution MRI. Our analyses investigated trajectories of speech production (e.g. pairwise variablity index and word duration) and associations with cortical atrophy in the patients. At first presentation, word duration differentiated the nonfluent and logopenic cases statistically, but the range of scores overlapped substantially across groups. Longitudinally, we observed progressive deterioration in pairwise variability index and word duration specific to the non-fluent group only. The pairwise variability index showed particularly strong associations with progressive atrophy in speech motor programming brain regions. Of novelty, our results uncovered a key role of the right frontal gyrus in underpinning speech motor programming changes in non-fluent cases, highlighting the importance of right brain regions in responding to progressive neurological changes in the speech motor network. Taken together, our findings validate the use of a new metric, the pairwise variability index, as a robust marker of apraxia of speech in contrast to more generic measures of speaking rate. Sensitive/specific neuroimaging biomarkers of the emergence and progression of speech impairments will be useful to inform theories of the pathomechanisms underpinning impaired speech motor control. Our findings justify developing more sensitive measures of rhythmic temporal control of speech that may enable confident detection of emerging speech disturbances and more sensitive tracking of intervention-related changes for pharmacological, neuromodulatory, and behavioural interventions. A more reliable detection of speech disturbances has relevance for patient care, with predominance of progressive apraxia of speech a high-risk factor for later diagnosis of progressive supranuclear palsy or corticobasal degeneration.