Peripheral Vascular Tone Research Articles

Pulse oximetry-based perfusion index as a non-invasive indicator of systemic hemodynamics during spinal anesthesia in cesarean delivery

Background & Objectives: Placental perfusion is not autoregulated and is susceptible to effects of spinal anesthesia (SA) induced hypotension. The perfusion index (PI) is a non-invasive marker of peripheral vascular tone, and a higher PI indicates increased risk of hypotension following SA. This study aims to establish preoperative baseline PI in our local population and its correlation with incidence of intraoperative hypotension. Methods: This prospective observational study recruited 35 parturients who underwent elective lower segment cesarean section (LSCS). Preoperatively, baseline heart rate (HR), systolic blood pressure (SBP), mean arterial pressure (MAP) and PI were documented. SA was performed with 8 to 10 mg of injection bupivacaine 0.5% (hyperbaric) at L3–L4 interspace followed by co-loading with 1 L Hartmann solution. Hypotension was defined as SBP less than 80% of baseline or less than 90 mmHg. A bolus of phenylephrine 50 µg was given as rescue medication to treat the hypotension. Intraoperatively, degree of decrease in SBP, MAP and HR, as well as the amount of phenylephrine required was recorded every minute until delivery of the baby and 3 min thereafter. Results: The correlations between parturients’ baseline PI with the degree of decreases in systolic and mean arterial pressure (r = 0.81, P < 0.001 and r = 0.76, P < 0.001, respectively) and phenylephrine requirement (r = 0.761, p < 0.005) were recorded. This study identified that the patients with cut-off PI value of 3.2 were at higher risk for SA induced hypotension with a sensitivity of 85.9% and a specificity of 87.5% (P = 0.001). Conclusion: The patients with baseline cut-off perfusion index value of more than 3.2 were at higher risk for spinal anesthesia induced hypotension in elective cesarean section. Abbreviations: CO - cardiac output; LSCS - lower segment cesarean section MAP - mean arterial pressure; PI - perfusion index; SA - spinal anesthesia Keywords: Hypotension; Pulse Oximeter; Perfusion Index; Spinal Anesthesia; Cesarean section; Citation: Manap NSA, Zaini RHM, Shukeri WFWM, Omar SC, Abu Bakar MZ, Seevaunnamtum P. Pulse oximetry-based perfusion index as a non-invasive indicator of systemic hemodynamics during spinal anesthesia in cesarean delivery. Anaesth. pain intensive care 2024;28(5):927−932; DOI: 10.35975/apic.v28i5.2570 Received: July 23, 2024; Reviewed: September 02, 2024; Accepted: September 10, 2024

Role of Pleth variability index and perfusion index for predicting hypotension following spinal anaesthesia in patients undergoing caesarean section

Pleth variability index and perfusion index are noninvasive continuous hemodynamic monitors that can assess peripheral vascular tone and intravascular volume status and thus can predict hypotension following spinal anaesthesia. Spinal anaesthesia is the choice of anaesthesia in caesarean sections. Approximately 70% of patients will develop hypotension after spinal anaesthesia, which can lead to maternal and fetal complications. Thus, the Pleth Variability Index (PVI) and perfusion index (PI) allow the identification of patients with an increased susceptibility to hypotension following spinal anaesthesia.: This prospective observational study was conducted in a tertiary care centre with 102 obstetric patients undergoing spinal anaesthesia for caesarean section in the age group of 18-35 years who were full term with ASA≤ grade II, BMI 35kg/m. Pleth variability index and Perfusion index were measured before and after spinal anaesthesia. The data was analysed using ROC and multiple linear regression models using SPSS software. In the hypotension group PVI and PI at one minute is higher than without the hypotension group. PVI at one minute is an independent factor for predicting hypotension following spinal anaesthesia (P=0.039). ROC analysis of baseline and one-minute PVI showed only one-minute PVI can predict hypotension with an AUC-0.633(95% CI-0.492-0.774) and an optimal cut-off value of 19.5. ROC analysis of baseline and one-minute PI revealed both baseline and one-minute PI could predict hypotension with AUC-0.507 (95% CI 0.378-0.636) and 0.540 (95% CI 0.410-0.682) respectively. The optimal cut-off of baseline PI for predicting hypotension is 2.5 with a sensitivity of 51.4%, specificity of 61.5% and one-minute PI is 4.5 with a sensitivity of 60.8% and specificity of 53.8%. Baseline PVI is not a predictor of hypotension and one-minute PVI ≥19.5 can predict hypotension following spinal anaesthesia. One minute PI ≥ 4.5 is more sensitive in predicting hypotension than Baseline PI ≥2.5.: The Pleth Variability Index and Perfusion Index are noninvasive monitors which can predict hypotension following spinal anaesthesia in cesarean sections.

Diagnosis Of Endothelial Dysfunction In Children With Neurocirculatory Dystonia: Test With Reactive Hyperemia

The article examines the role of nitric oxide in the regulation of peripheral vascular tone in children with neurocirculatory dystonia. When using a functional test with reactive hyperemia, its high diagnostic significance was revealed; a decrease in the formation of nitric oxide in the vascular endothelium (endothelial dysfunction) was established in children with neurocirculatory dystonia (p <0.001).

First Real-Life Data on the Diving Response in Healthy Children.

Swimming and diving are popular recreational activities, representing an effective option in maintaining and improving cardiovascular fitness in healthy people. To date, only little is known about the cardiovascular adaption to submersion in children. This study was conducted to improve an understanding thereof. We used a stepwise apnea protocol with apnea at rest, apnea with facial immersion, and at last apnea during whole body submersion. Continuous measurement of heart rate, oxygen saturation, and peripheral resistance index was done. Physiologic data and analysis of influencing factors on heart rate, oxygen saturation, and peripheral vascular tone response are reported. The current study presents the first data of physiologic diving response in children. Data showed that facial or whole body submersion leads to a major drop in heart rate, and increase of peripheral resistance, while the oxygen saturation seems to be unaffected by static apnea in most children, with apnea times of up to 75s without change in oxygen saturation.

Exaggerated Peripheral and Systemic Vasoconstriction During Trauma Recall in Posttraumatic Stress Disorder: A Co-Twin Control Study

BackgroundIndividuals with posttraumatic stress disorder (PTSD) face an increased risk of cardiovascular disease, but the mechanisms linking PTSD to cardiovascular disease remain incompletely understood. We used a co-twin control study design to test the hypothesis that individuals with PTSD exhibit augmented peripheral and systemic vasoconstriction during a personalized trauma recall task. MethodsIn 179 older male twins from the Vietnam Era Twin Registry, lifetime history of PTSD and current (last month) PTSD symptoms were assessed. Participants listened to neutral and personalized trauma scripts while peripheral vascular tone (Peripheral Arterial Tone ratio) and systemic vascular tone (e.g., total vascular conductance) were measured. Linear mixed-effect models were used to assess the within-pair relationship between PTSD and vascular tone indices. ResultsThe mean age of participants was 68 years, and 19% had a history of PTSD. For the Peripheral Arterial Tone ratio analysis, 32 twins were discordant for a history of PTSD, and 46 were discordant for current PTSD symptoms. Compared with their brothers without PTSD, during trauma recall, participants with a history of PTSD had greater increases in peripheral (β = −1.01, 95% CI [−1.72, −0.30]) and systemic (total vascular conductance: β = −1.12, 95% CI [−1.97, −0.27]) vasoconstriction after adjusting for cardiovascular risk factors. Associations persisted after adjusting for antidepressant medication use and heart rate and blood pressure during the tasks. Analysis of current PTSD symptom severity showed consistent results. ConclusionsPTSD is associated with exaggerated peripheral and systemic vasoconstrictor responses to traumatic stress reminders, which may contribute to elevated risk of cardiovascular disease.

Electroacupuncture relieves portal hypertension by improving vascular angiogenesis and linking gut microbiota in bile duct ligation rats.

The pathological increase in the intrahepatic resistance and decrease peripheral vascular tone in the development of portal hypertension (PHT). PHT has been linked to lower microbial diversity and weakened intestinal barrier, and interplay alters inflammatory signaling cascades. Electroacupuncture (EA) may ameliorate the inflammatory response and limit arterial vasodilatation and portal pressure. This study addresses the possible mechanisms underlying putative hemodynamics effects of EA in PHT rats. PHT was induced by bile duct ligation (BDL) over 7 days in rats. BDL rats were treated with low-frequency EA (2 Hz) at acupoint, ST36, 10 min once daily for 7 consecutive days. EA significantly reduced portal pressure and enhanced maximum contractile responses in the aorta, and blunts the angiogenesis cascade in PHT rats. EA decreased the aortic angiogenesis signaling cascade, reflected by downregulated of ICAM1, VCAM1, VEGFR1, and TGFβR2 levels. In addition, EA preserved claudin-1, occludin, and ZO-1 levels in BDL-induced PHT model. Furthermore, EA demonstrates to have a positive effect on the gut Bacteroidetes/Firmicutes ratio and to reduce pro-inflammatory cytokines and endotoxins. These results summarize the potential role of EA in the gut microbiota could potentially lead to attenuate intestine injury which could further contribute to vascular reactivity in PHT rats.

Features of regional blood flow in young people with vitamin B<sub>12</sub> deficiency anemia

Aim. To investigate specific features of regional blood flow in the liver of young people with vitamin B12 deficiency anemia (VBDA).Materials and methods. A total of 64 patients diagnosed with VBDA with the median age of 38 years and 95% confidence interval [26; 49] were examined. Hemodynamic parameters of the liver and central circulation were assessed using pulsedwave Doppler ultrasound with color and power imaging. Statistical data was processed by Statistica 25.0.Results. At the onset of VBDA, the revealed hemodynamic disorders are primarily associated with a 13.8% decrease in the ratio of the linear velocity of the portal flow and the diameter of the portal vein, which leads to liver blood stagnation. A long medical history of VBDA is associated with the venous collector of hepatic hemodynamics and a decrease in the volume values (16.8%) against the background of increased peripheral vascular tone of hepatic vessels (23.5%). A correlation between the indicators of regional blood flow in the liver and the type of central hemodynamics was revealed, being most pronounced in severe VBDA and the hypokinetic hemodynamics type.Conclusion. Assessment of the regional blood flow of the liver was found to be an effective method for diagnosing the state of target organs in VBDA and for verifying the predictors of VBDA severity.

Role of perfusion index in early detection of hypotension following spinal anesthesia for cesarean section

ABSTRACT Background The most common drawback of spinal anesthesia (SA) is hypotension, which has adverse effects on both mother and fetus; consequently, early detection and management of spinal hypotension have been considered a very important topic in obstetric anesthesia. Additionally, the capability to ultimately diagnose hypotension could permit initiation of adequate treatment. The standard method to estimate blood pressure during cesarean section is noninvasive blood pressure measurement. However, periods of hypotension could be missed within a reasonable time frame. Methods Perfusion index (PI) and blood pressure were measured in 100 pregnant women during elective cesarean section under SA. Results PI had a significant negative correlation with the change occurred in systolic blood pressure (SBP) (r = −.432, p < .0001); by using univariate linear regression analysis, the PI explains 20.2% of variability in SBP as PI significantly predicts the change occurred in SBP (F = 24.8, p < .0001), as each one unit increase in PI, accompanied by a significant decrease in SBP by 2.089 (mm/hg), as (b, t, p) (−2.089, −4.987, .0001), respectively. There was a significant difference in SBP and PI before and after giving oxytocin bolus [(z = −1.9, P = .05) and (z = −4.3, P < .0001), respectively]. By comparing PI before vs. after taking ephedrine bolus, there was a significant decrease in median of PI [median of PI before 10 (5.5–15) vs. median of PI after 7.5 (6–15.5) (z = −6.6, P < .0001)]. Discussion After SA with sympathetic blockade, peripheral vascular tone declined and therefore PI increased. Conclusion PI could anticipate the incidence of hypotension during cesarean delivery with SA. Ephedrine effect could be evaluated rapidly by the alteration in the PI so that further need can be judged. Oxytocin has a significant impact on vascular tone with 5 international unit bolus, although it does not have a significant effect on blood pressure.

C-31 | Impact of Marijuana Use on Prevalence and Interventions in Peripheral Artery Disease

The growing legalization of marijuana use warrants investigation of its various effects on the vasculature. We aim to determine whether marijuana users have an increased risk of peripheral artery disease (PAD) and subsequent surgical intervention. De-identified patient data from the National Inpatient Sample (NIS) from 2016-2019 were queried. Inclusion criteria included a diagnosis of marijuana use and peripheral artery disease. Patients were further stratified based on any percutaneous lower extremity vascular intervention. Data was analyzed using SPSS software in a binary logistic regression model, a p value <0.001 was considered statistically significant, and samples were standardized for comparison using predicted probabilities. Of the 30m+ patients in the NIS from 2016 to 2019, there were 623,768 patients diagnosed as marijuana users. These patients had an average age of 37.4 years, even distribution across genders, were more likely to be white and more likely to be elective admissions (p<0.001). Of these patients, 2,424 (0.38%) were concomitantly diagnosed with PAD. Marijuana users were at more than three times the risk of developing PAD (OR= 3.68, p<0.001) but had no statistically significant increased risk for mortality or requiring percutaneous intervention (p<0.001). Marijuana users are at a markedly increased risk of being diagnosed with PAD but are at no increased risk of requiring intervention nor mortality from their peripheral ischemia. Possible mechanisms for this increased risk may involve changes in coagulability and peripheral vascular tone from marijuana use. Vigilant monitoring for disease screening and progression should be initiated earlier in the outpatient setting in conjunction with cessation counseling.

Perfusion index to predict post spinal hypotension in lower segment caesarean section.

It is important to predict and prevent post-spinal hypotension in lower segment cesarean section (LSCS). Peripheral vascular tone can be monitored as a perfusion index (PI) from a pulse oximeter. We aimed to study baseline PI as a predictor of post-spinal hypotension in LSCS. Prospective observational study conducted in a tertiary care teaching public hospital on patients posted for elective LSCS under spinal anesthesia. Baseline PI and hypotension were compared. A receiver operating characteristic (ROC) curve was plotted and data were analyzed using SPSS version 20. Among 90 females, 43 (47.8%) had a PI ≤3.5 and 47 (52.2%) had a PI >3.5. In the PI >3.5 group, 46 (97.9%) females had hypotension and required a high volume of IV fluids, and 29 (61.7%) required vasopressors, and the association with PI was statistically significant with Pearson's Chi-square values of 32.26 and 32.36, respectively (P = 0.001). In the ROC, the area under the curve (AUC) was 0.917, proving baseline PI >2.9 as an excellent classifier (P < 0.0001,95% confidence interval [CI] 0.840-0.965) and can predict hypotension with a sensitivity of 83.08% and specificity of 96.00%. Baseline PI >3.5 was associated with significant post-spinal hypotension and vasopressor administration in LSCS. We established baseline PI >2.9 can predict post-spinal hypotension with high sensitivity and specificity. PI is simple, quick, and non-invasive and can be used as a predictor for post-spinal hypotension in parturients undergoing LSCS so that prophylactic measures can be considered in at-risk patients for better maternal and fetal outcomes.

Harlequin Color Change in a Neonate Positive to COVID-19: Case Report

Background: Harlequin color change is a benign, idiopathic, self-limiting disorder characterized by an appearance of skin divided into two distinctly colored areas. Its etiology is unknown but thought to be caused by immaturity of hypothalamic regulation of peripheral vascular tone. COVID-19 infection in neonates is infrequent and rarely symptomatic, with only a few cases described in the literature. In isolation, both conditions have low incidence. This is the first case reported in the world literature of harlequin color change in a newborn who tested positive for COVID-19. There isn’t a single publication that links harlequin color change to COVID-19, yet. The Case: Newborn of a 34-year old mother. Who at 3 hours of life presented progressive respiratory distress with whimpering and cyanosis. At 20 hours presented a sudden color change in the right hemibody with unilateral hyperemia and contralateral pallor, simultaneous with a demarcated line separating the left and right sides of the body, involving the trunk, extremities and face, this remained for 10 minutes and then began to fade on its own until it disappeared completely. There were no changes in vital parameters associated with this phenomenon. Only one episode was reported. The transient character and the strict unilateral distribution of the manifestations did not confirm any etiology other than Harlequin phenomenon. Subsequently the patient evolved to respiratory deterioration, multiorgan failure (SOFA: 21), died at 22 days of life due to respiratory arrest.&#x0D; Conclusion: This is the first ever documented case in worldwide literature of harlequin color change in a neonate positive to COVID-19. Given the low incidence of both entities in isolation and the fact that they were discovered in the same patient, we suggest a strong possibility of SARS-CoV-2 to be the source of the harlequin phenomena in this case and should be considered as an indicator of severe COVID in newborns, but further studies that expand the selection of patients with this condition are needed. There is no literature linking the harlequin phenomenon with COVID-19.

The Usefulness of Perfusion Index Derived from a Pulse Oximeter in Predicting Hypotension following Spinal Anesthesia for Cesarean Section

Hypotension is a frequent complication of spinal anesthesia. Decrease in peripheral vascular tone that occurs during pregnancy is one of the factors causing hypotension in patients undergoing cesarean section under spinal anesthesia. Perfusion index derived from pulse oximeter can be an easy and non-invasive measure of peripheral perfusion. This study was conducted to test the usefulness of pulse oximeter in predicting hypotension following spinal anesthesia for cesarean section. In this study, 247 parturients undergoing elective cesarean section under spinal anesthesia were included. Parturients who had baseline PI&lt;3.5 were kept in Group I and parturients who had baseline PI&gt;3.5 were kept in Group II. All the patients were given 0.5% bupivacaine heavy 2.2 ml for spinal anesthesia. In group I, 30 patients (23.62%) had hypotension whereas in Group II, 119 patients (100%) had hypotension. The episodes of hypotension were significantly lower in Group I as compared to Group II (p&lt;0.001). The dose of mephentermine (p&lt;0.001) used was also significantly lower in Group I as compared to Group II. Therefore, we concluded that a baseline PI&gt;3.5 is a prediction of hypotension following spinal anesthesia in patients undergoing cesarean section.

An orderly sequence of autonomic and neural events at transient arousal changes

Resting-state functional magnetic resonance imaging (rsfMRI) allows the study of functional brain connectivity based on spatially structured variations in neuronal activity. Proper evaluation of connectivity requires removal of non-neural contributions to the fMRI signal, in particular hemodynamic changes associated with autonomic variability. Regression analysis based on autonomic indicator signals has been used for this purpose, but may be inadequate if neuronal and autonomic activities covary. To investigate this potential co-variation, we performed rsfMRI experiments while concurrently acquiring electroencephalography (EEG) and autonomic indicator signals, including heart rate, respiratory depth, and peripheral vascular tone. We identified a recurrent and systematic spatiotemporal pattern of fMRI (named as fMRI cascade), which features brief signal reductions in salience and default-mode networks and the thalamus, followed by a biphasic global change with a sensory-motor dominance. This fMRI cascade, which was mostly observed during eyes-closed condition, was accompanied by large EEG and autonomic changes indicative of arousal modulations. Importantly, the removal of the fMRI cascade dynamics from rsfMRI diminished its correlations with various signals. These results suggest that the rsfMRI correlations with various physiological and neural signals are not independent but arise, at least partly, from the fMRI cascades and associated neural and physiological changes at arousal modulations.

Cardiovascular autonomic nervous function in 7–12 years old children conceived naturally or by ART with frozen and fresh embryo transfer

Abstract Background Cardiovascular autonomic nervous functions (CANF) exert important homeostatic mechanisms to prevent major arterial blood pressure fluctuations by adjusting heart rate (HR), cardiac contractility, and peripheral vascular tone. Children conceived by assisted reproductive technologies (ART) are at risk of increased carotid intima-media thickness, insulin resistance, arterial stiffness, and hypertension. CANF is impaired in children with obesity and diabetes mellitus, and conductance artery stiffness is documented to influence CANF. CANF may therefore be hypothetized to be impaired in children conceived by ART. Purpose This is the first study to investigate whether children conceived by ART have impaired CANF as compared to naturally conceived children. Method CANF was studied in 105 singletons aged 7–12 years conceived naturally (NC, N=33) or by ART (frozen embryo transfer (FET, N=34) and fresh embryo transfer (Fresh ET, N=38)). CANF was evaluated with continuous non-invasive hemodynamic measurements (Finapres®) by the HR and blood pressure changes seen relative to rest during active standing, deep breathing and Valsalva, respectively. Results The descriptive data showed no difference in CANF measurements between our study groups (Table 1). In the multivariate analysis, only the Valsalva HR-ratio to rest was significantly higher in children conceived by FET as compared to NC children after adjustments for age, sex, BMI and maternal age at delivery (Figure 1). For all meaures, the effect size (Hedges d) ranged from 0.02 to 0.48. Conclusion In this study only the Valsalva HR-response between FET and NC groups were statistically significant after adjustment for confounders, and in general effect sizes were small. Our study suggests that children conceived by ART do not have a significantly impaired cardiovascular autonomic nervous function as compared to naturally conceived children. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation

Clinical evaluation and prevalence of hypertension in different areas of Pakistan Authors

Background: Hypertension is defined as a sustained systolic blood pressure greater than 140 mm Hg or sustained diastolic blood pressure greater than 90mm Hg. Hypertension occurs due to increased peripheral vascular arteriolar smooth muscle tone which leads to increased arteriolar resistance and reduced capacitance of the venous system. Primary objective: The purpose of this study was to determine the prevalence of hypertension in different areas of Pakistan and Azad Kashmir. Methods/Design: The survey was conducted among the population of different areas of Pakistan and Azad Kashmir, evaluating the dietary habits of the habitants, age factors, marital status, and job status. Setting: Data was taken from Rawalpindi Institute of Cardiology Pakistan. Participants: Data from 50 participants with different age groups was taken from the Rawalpindi Institute of Cardiology Pakistan. Intervention: Our 6th monthly survey showed that the major factors that exaggerate hypertension are, inappropriate diet, job stress, and workload, smoking in adults, age, and concomitant diseases. Primary Outcome Measures: The study is very effective for the community because it provides awareness about the emerging factors of hypertension and highlights the different ways of treating it both pharmacologically and non-pharmacologically. Results: The study revealed that people over 60 suffer more from hypertension. The disease was more common in working males than females. Smokers and patients suffering from other concomitant diseases were more prone to this disease. Conclusion: Studies help the community to modify their lifestyle to eradicate the disease. It will help in the early diagnosis of diseases and the appropriate therapy to enjoy a healthy and carefree lifestyle.

Correction of the Elevated Blood Pressure in Patients Undergoing Robot-Assisted Radical Prostatectomy

The aim of the study was to evaluate the role of urapidil hydrochloride for the management of abnormal cardiovascular response in patients undergoing robot-assisted radical prostatectomy (RARP).Material and methods. The total of 93 prostate cancer patients scheduled for elective RARP were included and randomized in two groups: urapidil (n=44) and standard anesthesia control group (n=49). Urapidil was used to control the elevated blood pressure intraoperatively. Central hemodynamic monitoring was performed at 5 steps of the surgery.Results. In the control group, the step 2 of the procedure was associated with elevated mean blood pressure (by 24.3%, P=0.045) and increased total peripheral vascular resistance (by 46.6%, P=0.011) compared with step 1, while in the urapidil group no significant changes in these parameters were found. In the urapidil group, the blood pressure was lower by 20.2% (P=0.047), afterload by 36.9% (P=0.02) vs the control group values, whereas the cardiac output was higher by 22.2% (P=0.043). Placing patient in the steep Trendelenburg position (step 3) resulted in a 22.4% increase in stroke volume (P=0.38) in the control group and a 19.2% increase in stroke volume (P=0.049) in the urapidil group compared with the previous step. Cardiac output in the urapidil group was higher by 34% (P=0.002) and blood pressure and vascular resistance were lower by 24.4% (P=0.031) and 45.7% (P=0.001), respectively, vs the control group. At steps 4 and 5, gradual stabilization of the hemodynamic parameters and peripheral vascular tone with significantly smaller differences between the groups were revealed.Conclusion. Urapidil was effective for maintaining central hemodynamic parameters in patients during robotic-assisted radical prostatectomy at step 2 of the procedure, avoiding blood pressure elevation at step 3 and significantly reducing the total peripheral vascular resistance compared with the control group.

P-772 Cardiovascular autonomic nervous function in singletons conceived after ART with frozen and fresh embryo transfer compared to naturally conceived children

Abstract Study question Do children conceived after assisted reproductive technologies (ART) with frozen or fresh embryo transfer have altered cardiovascular autonomic nervous function compared to naturally conceived children? Summary answer Cardiovascular autonomic nervous function was comparable in singletons conceived after ART with frozen or fresh embryo transfer, and naturally conceived children. What is known already Cardiovascular autonomic nervous function (CANF) exert important homeostatic mechanisms to prevent major arterial blood pressure fluctuations by adjusting heart rate, cardiac contractility, and peripheral vascular tone. CANF is impaired in children with obesity and diabetes mellitus, and conductance artery stiffness is documented to influence CANF. Previous studies have reported that children conceived after ART are at risk of increased carotid intima-media thickness; insulin resistance; arterial stiffness; and hypertension. This is the first study to investigate CANF in children conceived after ART. Study design, size, duration CANF was studied in 110 singletons aged 7-12 years conceived after frozen embryo transfer (FET, N = 35), fresh embryo transfer (fresh-ET, N = 39) or natural conception (NC, N = 36). Children were born between 2009 and 2013. This study was conducted between June 2019 and October 2021. Participants/materials, setting, methods Participants were identified through the Danish IVF and Medical Birth Registries. CANF was evaluated by heart rate (HR) changes (ratio to rest) during deep breathing; Valsalva; and active stand test with continuous non-invasive hemodynamic measurements. Anthropometric measures, fasting blood samples, and maternal questionnaires were collected. Neonatal and maternal pregnancy data were collected from the Medical Birth Registry. Children with a history of congenital heart disease or mothers with gestational diabetes or diabetes mellitus were excluded. Main results and the role of chance A total of 110 singletons with a median age of 9.0 years were included in this study. We found no significant associations between conception method and our measures of CANF. For FET, fresh-ET, and NC, respectively, the HR-ratio for deep breathing was 1.62 (0.2 SD), 1.62 (0.16) and 1.63 (0.17) (ANOVA-P = 0.97). For Valsalva, the HR-ratio was 1.97 (0.4), 1.88 (0.41) and 1.63 (0.17), respectively (ANOVA-P = 0.24). For the active stand test, the HR-ratio was 1.43 (0.17), 1.41 (0.2) and 1.43 (0.19), respectively (ANOVA-P = 0.91). Associations remained non-significant after adjustment for age, sex, body surface area, body mass index, and mean arterial pressure. In the multivariate analysis, several other factors were significantly associated with HR-ratio for deep breathing: age (β = -0.06, P = 0.03), body surface area (β = 0.79, P = 0.01), body mass index (β = -0.03, P = 0.04), and mean arterial pressure (β =-0.01, P = 0.03), but not with other measures of CANF. All data for CANF were within reference limits. Also, mothers in the ART groups were older at childbirth than NC group as expected. No significant differences were observed in clinical characteristics, including neonatal and other maternal data. Limitations, reasons for caution This study is limited by its observational design to draw any firm conclusion on causality. Also, it is a limitation that the pubertal status was not systematically assessed as pubertal hormones may play a role in CANF. Wider implications of the findings This study contributes to the current knowledge about cardiovascular health risks in ART children. Reassuringly, this study found that children conceived after ART (frozen or fresh-ET) did not exhibit impaired cardiovascular autonomic nervous function compared to naturally conceived children. Trial registration number NCT03719703

A study to evaluate perfusion index as a predictor of hypotension following spinal anesthesia for caesarean section.

Background and Aims:The perfusion index (PI) has been used as a marker of peripheral perfusion. A lower PI indicates greater peripheral vascular tone and increased risk of hypotension following spinal anesthesia. The present study was conducted to evaluate and correlate perfusion index (PI) with incidence of hypotension following spinal anesthesia for caesarean section.Material and Methods:The present prospective, double blind, observational study included sixty full term parturients in the age group 18-35 years belonging to American Society of Anesthesiologists (ASA) physical status I and II, having singleton pregnancy undergoing caesarean section under spinal anesthesia. On the basis of baseline PI, patients were allocated into one of the two groups: Group I (n = 30) Patients with baseline PI ≤.3.5 and Group II (n = 30) Patients with PI >3.5.Results:The incidence of hypotension in group I was 40% as compared to 73.3% in group II (p = 0.009). Thus, the incidence of hypotension in group II with baseline PI >.3.5 was more as compared to group I. Patients in group II with baseline PI >.3.5 had significantly more episodes of hypotension as compared to those in group I with baseline PI ≤3.5.Conclusion:PI can be used as a useful tool for predicting hypotension in parturients undergoing elective caesarean section under spinal anesthesia in everyday practice.

Interplay between baroreflex sensitivity, obesity and related cardiometabolic risk factors (Review).

The baroreflex represents a rapid negative feedback system implicated in blood pressure regulation, which aims to prevent blood pressure variations by regulating peripheral vascular tone and cardiac output. The aim of the present review was to highlight the association between baroreflex sensitivity (BRS) and obesity, including factors associated with obesity, such as metabolic syndrome, hypertension, cardiovascular disease and diabetes. For the present review, a literature search was conducted using the PubMed database until August 21, 2021. The searched terms included ‘baroreflex’, and other terms such as ‘sensitivity’, ‘obesity’, ‘metabolic syndrome’, ‘hypertension’, ‘diabetes’, ‘gender’, ‘aging’, ‘children’, ‘adolescents’, ‘physical activity’, ‘bariatric surgery’, ‘autonomous nervous system’ and ‘cardiometabolic risk factors’. Obesity and its related metabolic disorders can influence baroreflex functionality and decrease BRS, mostly by potentiating sympathetic nervous system activity. Obesity induces inflammation, which can increase sympathetic system activity and lead to a higher incidence of cardiovascular events. Obesity also represents an important risk factor for hypertension through numerous mechanisms; in this setting, dysfunctional baroreceptors are not able to protect against constantly elevated blood pressure. Furthermore, diabetes mellitus and oxidative stress result in deterioration of BRS, whereas aging is also generally related to reduced cardiovagal BRS. Differences in BRS have also been observed between men and women, and overall cardiovagal BRS in healthy women is less intense compared with that in men. BRS appears lower in children with obesity compared with that in children of a healthy weight. Notably, physical exercise can increase BRS in both hypertensive and normotensive subjects, and BRS can also be significantly improved following bariatric surgery and weight loss. In conclusion, obesity and its related metabolic disorders may influence baroreflex functionality and decrease BRS, and baroreceptors cannot protect against the constantly elevated blood pressure in obesity. However, following bariatric surgery and weight loss, BRS can be significantly improved. The present review summarizes the role of obesity and related metabolic risk factors in BRS, providing details on possible mechanisms and shedding light on their interplay leading to autonomic neuropathy.

Association between preoperative toe perfusion index and maternal core temperature decrease during cesarean delivery under spinal anesthesia: a prospective cohort study

BackgroundThe main mechanism of body temperature decrease during cesarean delivery under spinal anesthesia is core-to-peripheral redistribution of body heat, attributable to vasodilation. Perfusion index (PI) obtained with a pulse oximeter helps to assess peripheral perfusion dynamics by detecting the change in peripheral vascular tone. This study aimed to examine whether preoperative toe PI could predict the decrease in core temperature induced by spinal anesthesia during cesarean delivery.MethodsParturients undergoing scheduled cesarean delivery under combined spinal-epidural anesthesia from September 2019 to March 2020 were enrolled in this single-center prospective cohort study. All parturients received 0.5% hyperbaric bupivacaine (10 mg) with fentanyl (15 μg) intrathecally. A pulse oximeter probe was placed on the left second toe for continuous PI measurement. The 3 M™ Bair Hugger™ Temperature Monitoring System placed over the right temporal region was used to record core temperature over time. We evaluated the association between the maximum core temperature decrease, which is the primary outcome, and the preoperative toe PI at operating room (OR) admission using a segmented regression model (SRM) and a generalized additive model (GAM). The maximum core temperature decrease was defined as the difference between core temperature at OR admission and minimum intraoperative core temperature.ResultsForty-eight patients were evaluated. In the SRM, the slope for the association between the maximum core temperature decrease and the preoperative toe PI changed from 0.031 to 0.124 after PI = 2.4%. Likewise, with the GAM, there was a small core temperature decrease when preoperative toe PI was greater than 2.0 to 3.0%.ConclusionsLow preoperative toe PI was associated with maternal core temperature decrease during cesarean delivery under spinal anesthesia. Preoperative toe PI is a simple, non-invasive, and effective tool for the early prediction of perioperative core temperature decrease during cesarean delivery.Trial registrationUMIN Clinical Trials Registry (registry number: UMIN000037965).