Vasoconstriction during non-hypotensive hypovolemia is not associated with activation of baroreflex: A causality-based approach.

Non-hypotensive hypovolemia simulated with oscillatory lower body negative pressure in the range of -10 to -20 mmHg is associated with vasoconstriction {increase in total peripheral vascular resistance (TPVR)}. Due to the mechanical stiffening of vessels, there is a disjuncture of mechano-neural coupling at the level of arterial baroreceptors which has not been investigated. The study was designed to quantify both the cardiac and vascular arms of the baroreflex using an approach based on Wiener-Granger causality (WGC) - partial directed coherence (PDC). Thirty-three healthy human volunteers were recruited and continuous heart rate and blood pressure {systolic (SBP), diastolic (DBP), and mean (MBP)} were recorded. The measurements were taken in resting state, at -10 mmHg (level 1) and -15 mmHg (level 2). Spectral causality - PDC was estimated from the MVAR model in the low-frequency band using the GMAC MatLab toolbox. PDC from SBP and MBP to RR interval and TPVR was calculated. The PDC from MBP to RR interval showed no significant change at -10 mmHg and -15 mmHg. No significant change in PDC from MBP to TPVR at -10 mmHg and -15 mmHg was observed. Similar results were obtained for PDC estimation using SBP as input. However, a significant increase in TPVR from baseline at both levels of oscillatory LBNP (p-value <0.001). No statistically significant change in PDC from blood pressure to RR interval and blood pressure to TPVR implies that vasoconstriction is not associated with activation of the arterial baroreflex in ≤-15 mmHg LBNP. Thereby, indicating the role of cardiopulmonary reflexes during the low level of LBNP simulated non-hypotensive hypovolemia.

Coronary artery disease and its vascular associates in patients with chronic nonsurgical hypoparathyroidism.

OBJECTIVE: Patients with chronic hypoparathyroidism (cHypoPT) are prone to intracranial-calcification, cataract and nephrocalcinosis. In this study, we systematically investigated the possibility of increased coronary artery calcification (CAC) and coronary artery disease (CAD) in them. DESIGN: Cross-sectional. PATIENTS AND MEASUREMENTS: Ninety-four nonsurgical cHypoPT (M:F = 50:44; age = 45 ± 15 years) with 18.6 ± 9.3 years of illness were assessed. Those with dyspnoea, angina, syncope, abnormal electrocardiogram, echocardiography or significant CAC underwent coronary angiography or myocardial-perfusion-stress imaging. Their lipid parameters and high-sensitivity C-reactive protein (hsCRP) were compared with age-matched healthy controls (Group A, n = 101). The prevalence of CAC in cHypoPT was compared with that of subjects referred from cardiology-clinics (Group B, n = 148, age = 52 ± 11 years). RESULTS: One of 94 cHypoPT had known CAD. On screening, 17 cHypoPT required evaluation for CAD. Two of 17 had severe coronary stenosis, and 12 showed subclinical CAD. CAC and aortic-valve calcification occurred in 21.5% and 11.8%. Clinical and subclinical CAD, CAC and aortic-valve calcification in cHypoPT ≥50 years of age was 8.1%, 27.0%, 52.8% and 27.8%, respectively. Frequency of age-adjusted CAC was comparable between cHypoPT and control Group B (30.2% vs. 30.7%, p = .93). Elevated hsCRP was higher in cHypoPT than in controls A (52% vs. 32%, p < .01). Factors associated with CAD in cHypoPT were CAC and hypertension. However, CAD and CAC showed no association with long-term calcemic or phosphatemic control and intracranial-calcification in cHypoPT. CONCLUSIONS: Clinical and subclinical CAD was observed in 3.2% and 12.8% of cHypoPT patients. The increased prevalence of CAD, CAC and aortic-valve calcification in cHypoPT above 50 years of age suggested their careful cardiac evaluation during follow-up.

Effect of Yoga Based Cardiac Rehabilitation on Blood Pressure Variability and Baroreflex Sensitivity: RCT in Patients Post MI.

To assess the effects of 12 weeks Yoga based Cardiac Rehabilitation program on Blood Pressure Variability and Baroreflex Sensitivity in Eighty patients post myocardial infarction. Randomized controlled trial with two parallel groups. A tertiary care institution in India. The Yoga group received 13 hospital-based structured yoga sessions in adjunct to the standard care. Control Group participants received enhanced standard care involving three brief educational sessions on importance of diet and physical activity. Beat to beat arterial pressure variability and baroreflex sensitivity was determined non-invasively. Baseline measurement was done at 3 weeks post Myocardial Infarction. The measurements were repeated at 13th week and at 26th week post MI. There was no significant difference between the groups in time domain indices of SBP variability. At 26th week post MI, after normalization the Low Frequency power increased in the yoga group as compared to the decrease in the standard care group (p = 0.02). Though the High Frequency power increased in both the groups, the magnitude of increase was higher in the standard care group (p = 0.005). However, the total power increased significantly in yoga group with a concurrent decrease in standard care group (p = < 0.001). The SBP All BRS was significantly different between the groups with an increase in the yoga group and a decline in standard care group (p = 0.003) at 13th week. A short-term Yoga based cardiac rehabilitation has additive effects in improving baroreflex sensitivity and dampening blood pressure variability post myocardial infarction in patients under optimal medication.The main trial is registered in Clinical Trials Registry-India (CTRI) (Ref. No: CTRI/2012/02/002408). In addition, CTRI has also been registered for the sub-study. (Ref. No: CTRI/2017/09/009925).

The effect of Bacillus coagulans Unique IS-2 supplementation on plasma amino acid levels and muscle strength in resistance trained males consuming whey protein: a double-blind, placebo-controlled study.

PURPOSE: The aim of the present study was to assess the effect of Bacillus coagulans Unique IS-2 supplementation on absorption and utilization of protein in resistance-trained males. METHODS: In this double blind, placebo-control trial, resistance-trained males (21.08 ± 2.84 years) were randomized to consume, either 20 g of whey protein powder {80% whey protein concentrate (WPC80), amounting to 15.4 g protein} with 2 billion CFU Bacillus coagulans Unique IS-2 (supplemental group) or 20 g of whey protein powder and lactose instead of Bacillus coagulans (placebo group) once daily for 60 days with a controlled resistance exercise protocol. The whey protein concentrate (WPC-80) given to both groups had a lactose content of 6.8%. Plasma-free amino acids (PFAAs) were determined at baseline, at 30 and 60 days of supplementation. Muscle strength, hypertrophy, VO2 max, and body composition, and other biochemical parameters were assessed at baseline and end line. RESULTS: A positive effect of probiotic Bacillus coagulans Unique IS-2 supplementation was observed on protein absorption as evidenced by an increase in total PFAA by + 16.1% (p = 0.004). Branched chain amino acids (BCAA) comprising isoleucine (p = 0.016), leucine (p = 0.001), and valine (p = 0.002) were increased by + 33.1% in ITT analysis as compared to placebo after 60 days. At 30 days an increase in isoleucine by + 35% (p = 0.113), leucine by + 43% (p = 0.032), and valine by + 32% (p = 0.017) was observed in ITT analysis. Probiotic effect was shown on exercise performance as evidenced by an increase in one RM of leg press and vertical jump power by + 16.61% (p = 0.024) and + 7.86% (p = 0.007), respectively. CONCLUSION: Significantly increased absorption of BCAA with supplementation of B. coagulans Unique IS-2 along with whey protein and improvement in leg press and vertical jump power was noted indicating the positive effect of the probiotic on muscle power in the lower body. TRIAL REGISTRATION NUMBER: CTRI/2017/03/008117; Date:16.03.2017.

High-frame-rate A-mode ultrasound for calibration-free cuffless carotid pressure: feasibility study using lower body negative pressure intervention.

PURPOSE: Existing technologies to measure central blood pressure (CBP) intrinsically depend on peripheral pressure or calibration models derived from it. Pharmacological or physiological interventions yielding different central and peripheral responses compromise the accuracy of such methods. We present a high-frame-rate ultrasound technology for cuffless and calibration-free evaluation of BP from the carotid artery. The system uses a pair of single-element ultrasound transducers to capture the arterial diameter and local pulse wave velocity (PWV) for the evaluation of beat-by-beat BP employing a novel biomechanical model. MATERIALS AND METHODS: System's functionality assessment was conducted on eight male subjects (26 ± 4 years, normotensive and no history of cardiovascular risks) by perturbing pressure via short-term moderate lower body negative pressure (LBNP) intervention (-40 mmHg for 1 min). The ability of the system to capture dynamic responses of carotid pressure to LBNP was investigated and compared against the responses of peripheral pressure measured using a continuous BP monitor. RESULTS: While the carotid pressure manifested trends similar to finger measurements during LBNP, the system also captured the differential carotid-to-peripheral pressure response, which corroborates the literature. The carotid diastolic and mean pressures agreed with the finger pressures (limits-of-agreement within ±7 mmHg) and exhibited acceptable uncertainty (mean absolute errors were 2.4 ± 3.5 and 2.6 ± 4.0 mmHg, respectively). Concurrent to the literature, the carotid systolic and pulse pressures (PPs) were significantly lower than those of the finger pressures by 11.1 ± 9.4 and 11.3 ± 8.2 mmHg, respectively (p < .0001). CONCLUSIONS: The study demonstrated the method's potential for providing cuffless and calibration-free pressure measurements while reliably capturing the physiological aspects, such as PP amplification and dynamic pressure responses to intervention.

Aerobic and anerobic contamination of mobile phones of health personnels with probable transfer of bacterial microbes to their hands at a tertiary care hospital of India.

Background and Aims: Mobile phone (MP) contamination of health personnels (HPs) in hospitals is a potential health hazard to the patients and the HP themselves. However, transfer of microbes from MPs of HP to their hands has not been demonstrated before, which would make potential threat into an actual peril. The primary objective was to determine aerobic and anerobic bacterial contamination of MP and hands of HP. The secondary objective was to determine probable transfer of bacterial microbes from MP to hands of tested HP. Material and Methods: Three swabs each were taken from 374 HP first from their MP, second from their dominant hand and third from their dominant hand after cleaning with disinfectant followed by a mock phone call of one minute (DHM). Aerobic and anerobic bacterial microbes were identified with standard methods. Results: Three hundred twenty-two HPs were recruited. Bacterial contamination was seen in 92% MP, 85% dominant hands, and 68% DHM of tested HP. Of these, contamination with potentially pathogenic bacterias (PPB) was 50% in MP, 25.6% in hands, and 31% in DHM. Anerobic contamination (1.6%) was present on MP but not in hands or DHM. In 54.7% HP, there was presence of similar bacterial microbes in MP and DHM of which 30% were PPB. When disinfectant was used in non-protocolized way in DHM, decrease in aerobic spore forming bacteria (ASB) was seen but not of gram-positive and gram-negative bacterial microbes. Conclusion: There is significant aerobic bacterial contamination, including PPB, seen in MP, hands, and DHM of HP in a tertiary care hospital of India; however, anerobic bacterias are found only in MP. Similar bacterial microbes in MP and DHM point to probable transfer of aerobic bacterias from MP to hands of HP which does not decrease when hand disinfectants are used in non-protocolized way, which is a point of concern.

Student perceptions on synchronous virtual versus face-to-face teaching for leader-centered and participant-centered postgraduate activities during COVID-19.

Consequent to the unprecedented COVID-19 pandemic, pedagogic changes were introduced in postgraduate courses in Physiology, where face-to-face teaching was replaced with synchronous virtual mode for leader-centered (seminar, symposium) and participant-centered (journal club, group discussion) academic activities. We hypothesized that the effectiveness of virtual and face-to-face modes as perceived by postgraduate students in terms of facilitating their overall learning may differ across the spectrum of leader-centered and participant-centered activities. To assess the same, we designed and administered a comprehensive, structured, and validated feedback questionnaire. Postgraduate students (n = 29) rated virtual sessions significantly more convenient, but less attentive and comprehensible, and reported better audiovisual experience during face-to-face sessions. Students rated flexibility to attend, self-paced learning, ability to revise, lookup for information in real time, and accessibility to distant expertise as important features of virtual sessions and instant feedback, eye-to-eye contact, and ability to interact in the group for face-to-face sessions. Virtual and face-to-face sessions were perceived as equally effective in facilitating their overall learning for the conduct of leader-centered seminars and symposia. However, face-to-face sessions were considered more effective for the conduct of participant-centered group discussions and journal clubs. During the pandemic, students perceive the synchronous virtual mode as an equally effective alternative for the conduct of leader-centered academic activities, but face-to-face teaching is still preferred for the conduct of participant-centered academic activities.

Adaptive strategies to conduct participant-centric structured virtual group discussions for postgraduate students in the wake of the COVID-19 pandemic.

In the wake of COVID-19, the postgraduate activities in physiology were shifted from live (face-to-face teaching) to virtual mode. This transition posed a challenge to postgraduate students and faculty moderators, especially for participant-centric group discussion, wherein face-to-face interaction contributes significantly to active learner engagement. To bridge the gap between live group discussion (GD) and virtual GD in the conventional format (VGD), we implemented an innovative yet feasible multistep approach of conducting structured virtual group discussion (sVGD). It involved priming of students during the preparatory phase and incorporation of the Tuckman model of group dynamics, which consists of sequential substages of forming, storming, norming, and performing into the virtual format. Unsupervised synchronous and asynchronous, as well as supervised synchronous interactions within and in between the minigroups in a structured way, led to active engagement of students with one another and the moderator, despite the constraints imposed by the virtual format. After establishing the feasibility of the approach during the first GD (sVGD-1), sVGD-2 was conducted, further refining the approach, and feedback was obtained from the postgraduate students. Pre-GD feedback revealed that the live session was preferred over virtual for the conduct of GD, whereas both live GD and sVGD were perceived to be more effective than VGD in the post-GD feedback. Such pedagogical innovations may also help to address the challenges posed in traditional teaching across the undergraduate and postgraduate courses in medical education and beyond during such unforeseeable circumstances.

IUPS Physiology Education Workshop series in India: organizational mechanics, outcomes, and lessons.

Active learning promotes the capacity of problem solving and decision making among learners. Teachers who apply instructional processes toward active participation of learners help their students develop higher order thinking skills. Due to the recent paradigm shift toward adopting competency-based curricula in the education of healthcare professionals in India, there is an emergent need for physiology instructors to be trained in active-learning methodologies and to acquire abilities to promote these curriculum changes. To address these issues, a series of International Union of Physiological Sciences (IUPS) workshops on physiology education techniques in four apex centers in India was organized in November 2018 and November 2019. The "hands-on" workshops presented the methodologies of case-based learning, problem-based learning, and flipped classroom; the participants were teachers of basic sciences and human and veterinary medicine. The workshop series facilitated capacity building and creation of a national network of physiology instructors interested in promoting active-learning techniques. The workshops were followed by a brainstorming meeting held to assess the outcomes. The aim of this report is to provide a model for implementing a coordinated series of workshops to support national curriculum change and to identify the organizational elements essential for conducting an effective Physiology Education workshop. The essential elements include a highly motivated core organizing team, constant dialogue between core organizing and local organizing committees, a sufficient time frame for planning and execution of the event, and opportunities to engage students at host institutions in workshop activities.

Contribution of systemic vascular reactivity to variability in pulse volume amplitude response during reactive hyperemia.

PURPOSE: The aim of the present study was to investigate why the magnitude of reactive hyperemia (RH) observed by pulse volume amplitude (PVA) after arm occlusion differs greatly among study subjects. METHODS: Healthy subjects (n = 12) in the age range of 22-30 years participated in this study. Vascular reactivity was assessed by measuring the changes in finger PVA simultaneously in the test (occluded arm) and control arm (contralateral non-occluded arm) using two separate Photoplethysmographic sensors. Short-term HRV was computed from simultaneously acquired lead II ECG signal to monitor the changes in cardiac sympathetic nervous activity. RESULTS: The observed coefficient of variation for inter-subject variability in PVA response in test arm during second minute of RH was 115.3%. In the control arm, significantly reduced PVA was observed during the period of occlusion as well as RH. This observation was corroborated by simultaneously acquired short-term HRV which showed a significant rise in total power (p value < 0.005) and low-frequency (LF) power (p value < 0.05) during release of occlusion when compared to the baseline. A significant positive correlation (Spearman r = 0.33; p = 0.02) was observed between % change in PVA in the control arm and in the test arm for first 3 min of RH. CONCLUSIONS: Sympathetic activation possibly plays an important role in mediating the inter-subject variability of vascular responses during reactive hyperemia which warrants simultaneous recording of both the test and the control arm responses during RH to accurately assess endothelial function.

Planning, implementation, and evaluation of multicomponent, case-based learning for first-year Indian medical undergraduates.

Didactic lecture is an effective method to quickly pass on a high volume of information to a large number of students. However, if not well designed, lectures can be monotonous and provide only passive learning, with little scope for higher order learning skills. To address this drawback of lectures, we supplemented it with case-based learning (CBL), which has been shown to promote self-learning. After giving an overview of gastrointestinal physiology through lectures, CBL on peptic ulcer disease was implemented for first-year Bachelor of Medicine, Bachelor of Surgery students. The present study aimed to evaluate the students' and teachers' opinions on the notion of supplementing lectures with CBL. In previous reports, discussion using clinical cases was primarily employed as the solitary component for conducting CBL. In the present study, three different but mutually exclusive components, such as case discussion, concept map, and critical thinking exercise on a specific topic in gastrointestinal pathophysiology, were integrated to form the multicomponent CBL (MC-CBL). Students reported that MC-CBL could promote application of the knowledge learned in lectures in a more appropriate context (92.42% positive response), enhance their learning efficiency (98.46% positive response), promote their active participation in the learning process (98.48% positive response), and help them in integrating physiological concepts with clinical science (98.46% positive response). Teachers observed that MC-CBL could promote active learning, analytic, and problem-solving skills of students. In conclusion, MC-CBL appeared to be an effective supplement for the lectures, providing an opportunity for the students to relate the knowledge learned during lectures.

Impaired systemic vascular reactivity & raised high-sensitivity C reactive protein levels in chronic obstructive pulmonary disease.

BACKGROUND & OBJECTIVES: Chronic obstructive pulmonary disease (COPD) is characterized by slowly progressive airflow limitaion, chronic lung inflammation and associated systemic manifestations. The objective of this preliminary study was to investigate the levels of high sensitivity C reactive protein (hs CRP) and tumour necrosis factor-α (TNF-α) as markers of systemic inflammation and assessment of systemic vascular reactivity that may play an important role in development of cardiovascular disease in COPD patients. METHODS: Systemic vascular reactivity was assessed non-invasively by measuring peripheral pulse waveform changes during reactive hyperemia (RH) in 16 COPD patients and 14 controls by photoplethysmography technique (PPG). Parameters measured were pulse wave amplitude (PWA), slope and pulse transit time (PTT). Tumour necrosis factor-α (TNF-α) and hs CRP were measured as markers of inflammation. RESULTS: PWA during the 1 st , 2 nd and 3 rd minutes post release of occlusion were significantly higher than the baseline means in controls, whereas in the patient group there was no significant change in the PWA during any of the observed time periods following release of occlusion, in comparison to the baseline means. Similar results were observed in slope values for patients and controls. Maximum percentage change in PWA during RH with reference to baseline was significantly lower in patients as compared to controls (26.78±20.19 vs 57.20±19.80%, p<0.001). Maximum percentage change in slope during RH with reference to baseline was significantly lower in patients as compared to controls (19.77±10.73 vs 39.25±13.49%, P<0.001). A vascular tone response as represented by PTT was also impaired in the 3 rd minute of RH as compared to baseline mean values in COPD patients only. INTERPRETATION & CONCLUSIONS: Our findings showed raised hs CRP levels and impaired systemic vascular reactivity in COPD patients. Whether these may increase the risk of cardiovascular disease in COPD patients need to be confirmed in future studies with large sample size and appropriate study design.

Waist Circumference Rather than Body Mass Index is Better Indicator of Insulin Resistance in Type 2 Diabetes Mellitus in North Indian Population.

Obesity and insulin resistance (IR) are associated with type 2 diabetes mellitus (DM). Obesity can be quantified by body mass index (BMI) and waist circumference (WC). Similarly, IR is commonly quantified by fasting-plasma-insulin (FPI) and Homeostatic model assessment (HOMA-IR). We aimed our study to find correlation between obesity-parameters and IR especially in the Indian population where despite lower BMI there is more prevalence of type 2 DM. In 34 uncomplicated patients of type 2 DM weight and WC were measured and BMI was calculated. HOMA-IR and FPI level were estimated to assess IR. Significant correlation was found between HOMA-IR and WC (r = +0.368, P = 0.0324) but it was non-significant between HOMAIR and BMI. Correlations were also not significant between FPI and WC or BMI. In conclusion, HOMA-IR and WC are better measures of IR and obesity as compared to FPI and BMI, respectively in type 2 DM.

A Novel Practical to Demonstrate Systemic and Local Regulation of Circulation in a Human Subject.

Purpose of the study: Systemic and local regulation of peripheral circulation is a vital concept to be taught to undergraduate medical students. There is lack of an effective practical module to demonstrate and reinforce the theoretical understanding of this concept. Methodology: We designed a simple feasible novel practical using finger pulse recording coupled with hand grip test and reactive hyperemia protocol to elicit systemic and local regulation of peripheral circulation respectively. Main findings: The reduction in finger pulse amplitude during hand grip contralateral to the exercising hand demonstrates systemic regulation while the isolated ipsilateral increase in finger pulse amplitude during reactive hyperemia demonstrates local regulation. Conclusion: : Here we propose a simple novel practical for effective demonstration of systemic and local regulation of circulation for under-graduate teaching in physiology.

Vascular Responses to Post Occlusive Reactive Hyperemia and Systemic Inflammation in Overlap Syndrome of Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea.

BACKGROUND: Post-occlusive reactive hyperemia (RH) is impaired in Chronic Obstructive Pulmonary Disease (COPD) and Obstructive Sleep Apnea (OSA). The aim of the present study was to examine systemic vascular response and endothelial function in patients of Overlap Syndrome (OS) of COPD and OSA and also to investigate whether OS has any additional effect on endothelial dysfunction when compared to dysfunction caused by COPD alone. METHODS: 31 COPD patients and 13 healthy controls participated in the study. Overnight Polysomnogra was done to classify the patients into COPD only group (Apnea-Hypopnea Index <5) (n=15) and OS group (AHI >5) (n=16). Peripheral pulse waveform changes during reactive hyperemia were assessed using digital Photoplethysmography (PPG) technique in which pulse wave amplitude (PWA), Maximum slope of upstroke and Pulse Transit Time (PTT) were measured. C - reactive protein was assessed as marker of inflammation by ELISA. RESULTS: Maximum percentage changes in PWA during RH were significantly lower in the both COPD group [20.34(12.02-34.07)] (p<0.001) and Overlap Syndrome group [10.96(6.21-21.49)] (p<0.0001) as compared to Controls [49.79(46.03-65.32)], whereas amplitude responses were not significantly different in the COPD and OS group (p>0.05). Maximum percentage change in slope of upstroke showed similar responses in the three groups. CRP levels (mg/) were raised in COPD [11.60(1.75-15.00] (p<0.001) and OS group [12.52(5.28- 15.70))](p<0.0001) as compared to controls [0.59(0.58-0.91)]. Maximum percentage change in amplitude negatively correlated with serum CRP levels in COPD group (r=-0.557, p=0.03) and in OS group (r=-O.552, p= 0.02). FEV1% predicted positively correlated with maximum percentage change in amplitude in OS group(r=0.579, p=0.018). No correlation of AHI was found with any of the vascular function parameter in Overlap group. CONCLUSION: The patients with Overlap Syndrome have systemic inflammation and impaired reactive hyperaemia response. However, no additive effect of OSA was observed on impaired RH in patients with co-existing COPD.

Correction for blood pressure improves correlation between cerebrovascular reactivity assessed by breath holding and 6% CO(2) breathing.

BACKGROUND: Changes in cerebral blood flow velocity to hypercapnia are associated with changes in systemic blood pressure (BP). These confounding BP-dependent changes in cerebral blood flow velocity cause misinterpretation of cerebrovascular reactivity (CVR) results. The objective of the study was to determine the relationship between CVR assessed by breath holding and 6% CO2 breathing after correcting for BP-dependent changes in cerebral blood flow velocity. METHODS: In 33 patients of uncomplicated type 2 diabetes mellitus, CVR was assessed as percentage changes in cerebral blood flow velocity and cerebrovascular conductance index. RESULTS: Percentage change in cerebral blood flow velocity during breath holding was positively correlated with that of during 6% CO2 breathing (r = .35; P = .0448). CVR during breath holding and 6% CO2 breathing were better correlated when expressed as percentage changes in cerebrovascular conductance index (r = .49; P = .0040). Similarly, breath-holding test results expressed as percentage changes in cerebral blood flow velocity correctly identified only 37.5% of the poor reactors to 6% CO2 breathing. However, when the breath-holding test results were expressed as percentage changes in cerebrovascular conductance index, 62.5% of the poor reactors to 6% CO2 breathing were correctly identified indicating a better agreement between the test results obtained by the 2 methods. CONCLUSION: Cerebrovascular response to breath holding is better correlated with that of 6% CO2 breathing when changes in cerebral blood flow velocity were corrected for associated changes in BP.

Cardiovascular Autonomic Deficits in Different Types of Achalasia.

Background and objective Achalasia cardia is a primary esophageal motility disorder, and the etiopathology of this disease's progression is not known. Moreover, autonomic dysfunction has not been studied in different types of achalasia. In light of this, we aimed to address this lack of data in this study. Methods The diagnosis of achalasia was done using high-resolution esophageal manometry (HRM)-based Chicago classification v4.0. Autonomic function tests (AFT) such as the head-up tilt test, deep breathing test (DBT), Valsalva maneuver (VM), handgrip test (HGT), and cold pressor test (CPT), as well as the heart rate variability (HRV) test, were performed among the cohort and the results were compared with those of 39 age- and sex-matched healthy controls. Results AFT and HRV tests were done on 62 patients (30 achalasia type I, 28 type II, and 4 type III) and compared with 39 age- and sex-matched healthy controls. The mean duration of symptoms, high Eckardt score, and dysphagia were most common in type I achalasia, followed by type II and III. The results of AFT showed a generalized loss of parasympathetic and baroreflex-independent sympathetic reactivity in all types of achalasia. However, baroreflex-dependent cardiovascular adrenergic reactivity was normal. Regarding cardiac autonomic tone, there was a loss of parasympathetic and sympathetic influence, but sympathovagal balance was maintained. The severity of the loss of autonomic functions was higher in type I, followed by type II. Conclusions In all types of achalasia, parasympathetic reactivity, baroreflex-independent sympathetic reactivity, and cardiac autonomic tone were lower compared to healthy controls, and the severity of dysfunction increased during the progression of the disease from type II to type I.

Effect of "365 Breathing Technique" on Intraocular Pressure and Autonomic Functions in Patients With Glaucoma: A Randomized Controlled Trial.

PRCIS: Patients with primary open angle glaucoma were advised to follow the "365 breathing technique" for 6 weeks in addition to their pharmacological glaucoma treatment. It helped to reduce intraocular pressure (IOP), stress biomarker-cortisol, and improve autonomic dysfunction. OBJECTIVE: To study the effect of the "365 breathing technique" on IOP, autonomic functions, and stress biomarkers in patients with primary open angle glaucoma. METHODS: In this randomized, controlled, interventional trial, after randomization, 40 patients in the intervention group followed "365 breathing" (three times a day, breathing rate: 6 cycles/min for 5 min) in addition to their pharmacological glaucoma treatment and 40 patients in the control group continued only with their pharmacological glaucoma treatment. IOP, serum cortisol, heart rate variability (HRV), and heart rate response to deep breathing test (DBT) were recorded at preintervention and 6 weeks postintervention. RESULTS: The mean IOP, serum cortisol, parameters of the HRV test, and DBT were comparable between the two groups at baseline. At the 6-week follow-up, in the intervention group, mean IOP was significantly lower (16.09 ± 2.24 vs 18.38 ± 1.58 mm Hg, P = 0.03) and serum cortisol were significantly lower (13.20 ± 3.11 vs 14.95 ± 2.60 mcg/dL, P = 0.038) compared with the control group. In the HRV test, time domain analysis showed a significant difference in the root mean square of the successive difference between RR interval values between both groups at 6 weeks ( P = 0.015) pointing towards higher postintervention parasympathetic activation in the intervention group. In frequency domain analysis (HRV test), the ratio of the low-frequency component to the high-frequency component was significantly lower in the intervention group at 6 weeks (1.65 vs 1.79, P = 0.019) indicating a shift in sympathovagal balance towards greater vagal modulation.There was a significant increase in delta heart rate ( P = 0.019) and expiratory:inspiratory ratio ( P = 0.011) in the intervention group at 6 weeks when compared with baseline values, indicating improved parasympathetic reactivity to DBT. CONCLUSION: "365 breathing" technique can reduce IOP and serum cortisol, and improve autonomic dysfunction in patients with glaucoma.