Changes In Body Position Research Articles

Blood pressure measurement and nocturnal dipping patterns are heavily affected by body posture through changes in hydrostatic pressure between the arm and the heart.

Nocturnal blood pressure (BP) shows the highest predictive power for cardiovascular events. However, there is a poor reproducibility of personalized dipping patterns in single individuals. We hypothesize that changes in body position during sleep cause variations in hydrostatic pressure,leading to incorrect BP values and dipping classifications. 26 subjects aged 18-30 years, as well as 25 participants aged 50 years and older underwent ambulatory BP measurements on the left arm, as well as determination of the hydrostatic pressure difference between the cuff and heart level during BP measurement. We observed that the BP measurement cuff was above the heart level (negative hydrostatic pressure) mostly through the night. Laying on the right side revealed the largest hydrostatic pressure difference and maximum incorrect BP measurement, with a mean of -9.61 mmHg during sleep. Correcting for hydrostatic pressure led to reclassification of nocturnal hypertension in 14 subjects (27.5%). Dipping patterns changed in 19 participants (37.3%). In total, 25 subjects (49.0%) changed either their nocturnal hypertension and/or their dipping classification. Our findings underscore the importance of accounting for hydrostatic pressure in ambulatory BP monitoring. Changes in body posture during sleep provide a plausible reason for the variability seen in nocturnal dipping patterns. Further research should focus on incorporating hydrostatic pressure compensation mechanisms in 24-h BP measurement. Limiting the noticeable effect of hydrostatic pressure differences could greatly improve hypertension diagnosis, classification, and treatment monitoring.

Stress test protocols applied without treadmill and bicycle ergometer: procedures and interpretation

The article highlights the possibility of application of exercise tests without special equipment. The methodological features of conducting tests and their interpreting options are shown. Changed body position tests have been updated. The definitions of stress tests and exercise tests have been clarified. A classification of ergometers and indicators of monitored parameters has been worked out. Examples of medical reports are given. The application possibilities of stress tests were considered in real clinical practice at the stages of treatment and rehabilitation of patients with a wide range of nosologies. Tables for independently determining the exercise test results are presented. The methods can be used in pediatric practice. The article is addressed to a wide range of practitioners and functional diagnostics specialists.

Tracking autonomic nervous system activity using surface ECG: Personalized, multiparametric evaluation

We present a concise review of the background, pitfalls, and potential solutions for the noninvasive evaluation and continuous tracking of cardiac autonomic nervous system activity (ANSA), using surface-ECG-accessible parameters, including heart rate (HR), heart-rate variability (HRV), and cardiac repolarization. These parameters have provided insights into the dynamics of cardiac ANSA in controlled experiments and have proved useful in risk assessment with respect to sudden cardiac death and all-cause mortality in some patient populations, as well as in implantable device programming. Yet attempts to translate these parameters from the laboratory environment to ambulatory settings have been hampered by the presence of multiple uncontrolled factors, including changes in blood pressure, body position, physical activity, and respiration frequency. We show that a single-parameter-based, simplified cardiac ANSA evaluation in an uncontrolled ambulatory setting could be inaccurate, and we discuss several approaches to improve accuracy. Discerning cardiac ANSA effects in uncontrolled ambulatory environments requires tracking multiple physiological processes, preferably using multisensor, multiparametric monitoring and controlling some physiological variables (e.g., respiration frequency); data fusion and machine-learning-based analytics are instrumental for developing more accurate personalized ANSA evaluation.

Continuous intraocular pressure variations following positional transitions in normal subjects and open angle glaucoma patients using a contact lens sensor system.

To evaluate the efficacy of a novel contact lens sensor system (CLS) in detecting continuous intraocular pressure (IOP) variations following positional transitions, and to explore these IOP variation patterns among normal subjects, untreated glaucoma patients, and untreated ocular hypertension (OHT) subjects. This prospective comparative study included 20 normal subjects, 14 high tension glaucoma (HTG) patients, 16 normal tension glaucoma (NTG) patients, and 14 OHT subjects. Participants wore the CLS for continuous IOP monitoring while undergoing sequential body position changes: from sitting to supine to a 10° head-down tilt (HDT), with each position maintained for ten minutes. Continuous IOP parameters, including mean, peak, and fluctuation (peak minus valley) in each position, as well as increment (peak minus starting value), interval (time to arrive peak), and velocity (increment divided by interval) after two position transitions, were compared among different positions and groups, respectively. Normal subjects, HTG and NTG patients exhibited higher CLS IOP mean and peak in supine/HDT positions compared to sitting (P < 0.05), but the mean or peak in HDT did not significantly differ from that in supine (P > 0.2). In OHT, all IOP parameters showed no significant difference among various positions (P > 0.1), except for velocity. Comparisons among groups revealed that during the transition from sitting to supine, HTG demonstrated higher IOP increment than other three groups and higher velocity than normal subjects (P < 0.05). NTG patients exhibited no significant differences in IOP increment, interval and velocity, compared to normal subjects (P > 0.05). The CLS proved effective in continuously recording IOP responses following positional changes in normal and glaucomatous eyes. Transitioning from sitting to supine resulted in increased IOP among normal subjects, HTG and NTG patients, but not in OHT. Compared to normal subjects, this IOP increase was more pronounced and rapid in HTG, but comparable in NTG. WHAT IS KNOWN : Positional transitions can induce IOP variations, which differ among normal subjects and glaucoma patients, and potentially relate to glaucomatous neuropathy. However, prior findings are constrained by the discontinuity of traditional tonometry. This study utilized a novel contact lens sensor system (CLS) to continuously monitor IOP during positional transitions in normal subjects and untreated glaucoma/OHT subjects. Continuous IOP outcomes revealed that normal subjects, HTG patients, and NTG patients exhibited an increase in IOP when transitioning from sitting to supine, whereas OHT did not. Compared to normal subjects, this increase in IOP was more pronounced and rapid in HTG patients, but similar in NTG.

The impact of body position on neurofluid dynamics: present insights and advancements in imaging.

The intricate neurofluid dynamics and balance is essential in preserving the structural and functional integrity of the brain. Key among these forces are: hemodynamics, such as heartbeat-driven arterial and venous blood flow, and hydrodynamics, such as cerebrospinal fluid (CSF) circulation. The delicate interplay between these dynamics is crucial for maintaining optimal homeostasis within the brain. Currently, the widely accepted framework for understanding brain functions is the Monro-Kellie's doctrine, which posits a constant sum of intracranial CSF, blood flow and brain tissue volumes. However, in recent decades, there has been a growing interest in exploring the dynamic interplay between these elements and the impact of external factors, such as daily changes in body position. CSF circulation in particular plays a crucial role in the context of neurodegeneration and dementia, since its dysfunction has been associated with impaired clearance mechanisms and accumulation of toxic substances. Despite the implementation of various invasive and non-invasive imaging techniques to investigate the intracranial hemodynamic or hydrodynamic properties, a comprehensive understanding of how all these elements interact and are influenced by body position remains wanted. Establishing a comprehensive overview of this topic is therefore crucial and could pave the way for alternative care approaches. In this review, we aim to summarize the existing understanding of intracranial hemodynamic and hydrodynamic properties, fundamental for brain homeostasis, along with factors known to influence their equilibrium. Special attention will be devoted to elucidating the effects of body position shifts, given their significance and remaining ambiguities. Furthermore, we will explore recent advancements in imaging techniques utilized for real time and non-invasive measurements of dynamic body fluid properties in-vivo.

Ergonomics in Facial Plastic and Reconstructive Surgery: A Clinical Evaluation.

Surgeons experience a risk for physical strain and injury secondary to physical demands in the workplace. To minimize injury and maximize career longevity, physicians should be aware of ergonomics pitfalls and postural correction methods. This study investigates ergonomic trends in Facial Plastic and Reconstructive Surgery (FPRS) clinic by quantifying surgeons' and trainees' cervicothoracic spine posture. Participants completed a 22-item questionnaire to evaluate current ergonomic practices. A lightweight device was calibrated and attached to the mid-scapular region of participants, providing real-time posture feedback. The percentage of time in upright posture was recorded during clinical and operative workdays. Upright posture was defined as neutral spine positioning with acceptable mild to moderate deviations. Two FPRS attending surgeons, 1 FPRS fellow, and 11 otolaryngology residents participated over 12 months. Discomfort was most commonly reported in the neck, shoulders, and upper back during clinic. Symptoms were self-treated by changing body position, wearing specialized footwear, adjusting height of the chair or examination table, or ignoring discomfort. Eighty-two percent were unaware of ergonomic guidelines or appropriate considerations. Time spent in upright posture was significantly higher in clinic (84.9%) than in the OR (53.5%) (p < 0.001). Upright posture declined after reaching 6 work hours (p = 0.029); no such patterns were observed in the OR (p = 0.946). Although time spent in upright posture was objectively poorer in the OR, these data suggest ergonomics are an important consideration in the outpatient setting, with surgeons experiencing discomfort during and after clinic. Further investigation is warranted to identify actionable changes and promote healthy ergonomics. N/A Laryngoscope, 2024.

Forensic-radiological diagnosis of gunshot wounds

Although gunshot wounds are less common in Germany than in other countries, aproportion of suicides and violent crimes are committed with firearms, which is why basic knowledge of diagnosis is important. Fundamentals regarding forensic assessment of gunshot wounds are discussed alongside typical radiological findings. In addition to analyzing our own cases and evaluating official statistics, this article is based on adiscussion of basic research and expert recommendations. The article describes the characteristics of the bullet entry and exit as well as special features of the bullet trajectory, particularly in bony injuries, and discusses their significance for radiological findings. Pitfalls in interpretation, such as changes in body position and the deflection of projectile (fragments) in the body, are presented, as are the advantages of supplementary radiological diagnostics (projectile search before initiation of dissection, simple detection of an air embolism, clarity of bullet trajectory reconstruction). This article is intended to provide an overview of not only typical types of weapons and projectiles but also their effects on the body of the victim, which must be documented by the examiner.

Human body temperature and cardiovascular response to changes in ambient temperature and body posture

Health problems due to heat or cold exposure is closely related not only to body temperature (BT) but also to blood flow rate (BFR) and blood pressure (BP). Therefore, it is necessary to understand the physiological mechanisms of the human body, such as how these physiological quantities change and how they affect each other. In this study, to clarify the physiological mechanisms of the human body, we measured the whole-body distribution of BT and BFR, as well as BP, heart rate, and metabolic rate under changes in ambient temperature and body posture. A total of 19 subjects were tested in three cases, including the temperature up-step and down-step cases, where the ambient temperature changed from 28 °C to 38 °C or 18 °C in the supine position, and the posture change case, where the posture changed alternately between the supine and standing positions at an ambient temperature of 28 °C. The results showed that the core temperature was efficiently maintained due to BFR regulation, especially in the extremities, in response to changes in ambient temperature. Additionally, changes in cerebral BFR in response to changes in posture were suppressed due to regulation of BFR, especially in the lower limbs, and heart rate. Furthermore, in the extremities, the BFR not only in the skin but also in the subcutaneous tissue and muscle was estimated to increase in hot environments and decrease in cold environments.

Effect of body position during weaning from total liquid ventilation in piglets

ObjectiveTo determine if change in body position improves oxygen requirements and respiratory mechanics during the transition from total liquid ventilation (TLV) to gas ventilation. MethodsFourteen piglets underwent TLV, followed by a 2-hour weaning period under conventional gas ventilation. Subjects were randomized to the experimental group (Rotating – R), that was in prone position between the 10th and 30th minute of weaning, or to the static control group (Supine – S). ResultsOxygenation index was lower in the R group at 30 minutes in prone position than that in the S group (1.9 [1.6; 2.8] vs 3.5 [3.1; 5.1], p = 0.001). This difference disappeared when subjects resumed the supine position (4.2 [3.8; 4.7] and 4.7 [3.8; 5.4], p = 0.4, for the R and S groups, respectively). The change in body position did not affect respiratory system compliance or inspiratory capacity. ConclusionProne position improved oxygenation during weaning from TLV. The effect disappeared once piglets returned to the supine position.

Pemberian Posisi Semi Fowler untuk Meningkatkan Saturasi Oksigen pada Pasien Congestive Heart Failure di Ruang Intensive Care Unit

Congestive Heart Failure (CHF) is a medical condition that affects various body systems and causes the heart to be unable to pump blood properly to meet metabolic needs. To increase oxygen levels in CHF patients, one approach is to change body position. This study used a descriptive method to evaluate the impact of the semi-Fowler position on oxygen levels. This study involved 10 patients in the ICU Room of RSUD Ir. Soekarno Sukoharjo, with the semi-Fowler position at a 45° angle applied for 15 minutes after eating at 13:00, from 23 to 25 May 2023. Patients who met the inclusion criteria were those with oxygen saturation &lt;95%, while patients who refused or experienced complications were not included. The instruments used included the SOP for the 45° semi-Fowler position and the Mindray PM 60 oximeter. The results showed that the 45° semi-Fowler position could increase oxygen saturation by around 2%, with a variation in increase between 2% and 4%. In conclusion, the 45° semi-Fowler position can increase oxygen levels by around 3-4% in CHF patients, as well as help reduce shortness of breath.

A Study on the Effects of Different Positions on the Clinical Prognosis of Patients with Acute Ischemic Stroke.

The key to treating Acute Ischemic Stroke (AIS) is to rapidly reopen occluded blood vessels, restore blood flow, and rescue the ischemic penumbra. Treatment methods mainly include thrombolysis, endovascular intervention, etc. However, these treatments are limited by strict time windows and technical conditions. Simpler and more feasible methods to improve cerebral blood flow are currently a hot topic in clinical research. In recent years, several studies have shown that changes in body position can effectively improve cerebral blood flow in patients. However, the effect on the neurological functional prognosis of AIS remains inconclusive. This review has examined the effects of changes in body position on the clinical prognosis of AIS, combining relevant guidelines and the latest research. The study has provided evidence of an improvement in the clinical prognosis of AIS.

Upper body posture changes during sitting in female office workers with lower crossed syndrome

Background/Objective: Office workers are exposed to high levels of sedentary time. This sedentary time may have impacts on office workers which affect the normal movement patterns of sitting position caused by muscle tightness and weakness. The aims of this study were to investigate postural changes in lower crossed syndrome (LCS) on a head tilt angle (HTA), craniovertebral angle (CVA), sagittal shoulder angle (SSA), and trunk flexion angle (TFA) during 30 min sitting in female office workers. Methods: Fifty-four office workers who use computer for at least 4 h/day, work for at least 5 years were recruited. All subjects were evaluated their posture, muscle length and power and assigned into three groups: healty group ([Formula: see text]), LCS type A ([Formula: see text]), and LCS type B ([Formula: see text]). Testing posture was 30[Formula: see text]min sitting at computer workstation and typing on standardized with video record. Then three pictures were captured at four points of time from VDO records. All angles were measured two-way mixed ANOVA and post-hoc Tukey test was used to analyse the data. Results: Subjects with LCS type B have less CVA, SSA, and TFA than healthy and participants with LCS type A significantly during sitting at 0, 10, 20 and 30[Formula: see text]min. There was no significant difference in HTA among the three groups. Conclusion: Subjects with LCS type B showed significant the upper body posture changes compared with other groups.

Long-term stress exposure, cortisol level and cardiovascular activity and reactivity: Observations in patients with fibromyalgia.

Previous research suggested that exposure to long-lasting or repeated laboratory stressors may lead to rearrangement of cardiovascular control, with a shift of regulation mechanisms from dominant cardiac to dominant vascular influences between the early and late response phases, respectively. This study investigated whether similar rearrangement occurs during life stress accompanying chronic disease by analyzing also associations between cortisol level and cardiovascular variables in patients with fibromyalgia (FM). In 47 women with FM and 36 healthy women (HW), cardiovascular recordings were taken during active body posture changes (sitting, lying down, and standing). Moreover, hair cortisol concentration (HCC) was obtained. During standing, which involved orthostatic challenge, FM patients showed higher total peripheral resistance (TPR) but lower stroke volume (SV), cardiac output (CO), and baroreflex sensitivity than HW. During sitting and lying down, TPR was more closely associated with blood pressure (BP) than CO in FM patients; in contrast, CO was more closely associated with BP than TPR in HW. HCC correlated positively with TPR and BP in FM patients, but negatively with TPR and BP and positively with SV and CO in HW. Results suggest that chronic disease-related stress is associated with alterations in cardiovascular regulation toward greater involvement of vascular than cardiac mechanisms in BP control. Stress-related cortisol release may contribute to the long-term rearrangement of autonomic regulation. At the behavioral level, the dominance of vascular over cardiovascular control may relate to reduced somatic mobilization during an active fight-flight response in favor of passive and behaviorally immobile coping.

The human craniospinal venous system and its influence on postural intracranial pressure: a review.

The cerebral and spinal venous systems have similar functions but unique anatomical and physiological properties. CSF occupies space in the cranial and spinal vaults, is continuously produced, and has many roles, including maintaining a favorable environment for CNS structures. The influence of the cerebrospinal venous system on CSF dynamics has been theorized since the 1940s. Newer studies suggest venous outflow pattern alterations in response to changes in body position. However, the relationship of postural cerebrospinal venous outflow shifts with and their influence on CSF homeostasis is not well understood. The authors searched the published literature related to the anatomy and function of vertebral venous plexus (VVP), CSF, and positional cerebral venous flow characteristics. A comprehensive collection of literature was compiled and reviewed, and the relationship between cerebrospinal and venous system changes and alterations in body positions, with an emphasis on the craniocervical system, is discussed. The VVP is a network of valveless veins extending from the sacrum to the cranium that are interconnected with the cranial dural sinuses. The internal VVP occupies space within the extradural spinal canal and functions to return spinal venous blood to the heart, but it has additional properties, including the capability of bidirectional venous flow, an intraspinal dilatory capacity, and a role in cerebral venous outflow. When one rises to the upright position, CSF shifts toward the spinal canal and force vectors change, leading to reduced intracranial CSF pressure; simultaneously, cerebral venous outflow shifts from the jugular vein to the VVP outflow pathway. The venous outflow shift mechanism and its purpose are poorly understood. The authors review the known physiology of the system, identify gaps in knowledge to direct future research, and propose an interpretation of these data, concluding that position-dependent CSF and cerebrospinal venous shifts are part of a complementary positional craniospinal pressure regulation system that must be kept in balance for optimal CNS function. Current knowledge of the cerebrospinal venous anatomy, dynamic flow characteristics in response to gravity, and the venous system's influence on CSF suggests that the VVP plays a role in influencing CSF pressure, and the authors hypothesize that it plays a role in supporting intracranial pressure in the upright body posture. Further research is needed to better characterize the functional relationship of the VVP to CSF dynamics as well as identify potentially related disease states.

The influence of rhythmic gymnastics on the students’ movement creativity levels

This research aimed to determine rhythmic gymnastics' influence on students' movement creativity in class VII MTSS Al Ma'arif Cilageni. In this case, movement creativity is defined as changes in body position that can stimulate students' smoothness, flexibility, originality of thinking, detail orientation, and sensitivity. The research method employed was quantitative, particularly an ex post facto design. This study's population was 25 students of class VII. The instruments covering questionnaires, observations, and documents were tested for validity and reliability to ensure accurate and reliable data. Data analysis was carried out using descriptive statistics, describing the average score and percentage of each component of movement creativity levels. The research results show that students' movement creativity level is mostly in the medium category, namely 35%. The results indicate that the fluency and flexibility components needed to be improved, while the students' authenticity, detail orientation, and sensitivity were quite good. This means that more effective rhythmic gymnastics learning model is necessary to increase students' movement creativity, especially in terms of fluency and flexibility. The research results are expected to be valuable input for teachers to improve the quality of rhythmic gymnastics learning. Implementing the right learning model leads to more optimal and better movement creativity of students. Thus, it can support the development of their motor and cognitive skills.

Effects of light-intensity physical activity on cardiometabolic parameters in young adults with overweight and obesity: The SED-ACT randomized controlled crossover trial.

To investigate how a change in body position with light-intensity physical activity (PA) 'snacks' (LIPAS, alternate sitting and standing, walking or standing continuously) compared with uninterrupted prolonged sitting affects glucose metabolism and heart rate variability (HRV) parameters in young adults with overweight and obesity. We conducted a four-arm randomized controlled crossover trial. The following conditions were tested during an 8-h simulated workday: uninterrupted prolonged sitting (SIT), alternate sitting and standing (SIT-STAND; 2.5 h total), continuous standing (STAND), and continuous walking (1.0 mph; WALK). The primary outcome was to investigate how a change in body position (alternate sitting and standing, walking or standing continuously) compared with uninterrupted sitting affects mean 8-h glucose metabolism. Secondary outcomes included the effects on 2-h postprandial glucose concentrations, as well as on 8-h/24-h heart rate and HRV parameters, in the respective study arms. Capillary blood samples were drawn from an hyperemised earlobe in the fasted state and once every hour during each trial intervention by puncturing the earlobe with a lancet and collecting 20 μL of blood (Biosen S-Line Lab+; EKF diagnostics, Barleben, Germany). HRV was assessed for 24 h including the 8-h intervention phase, and a home phase by means of a Holter electrocardiogram. All participants received the same standardized non-relativised breakfast and lunch during the four trial visits. Seventeen individuals (eight women, mean age 23.4 ± 3.3 years, body mass index 29.7 ± 3.8 kg/m2, glycated haemoglobin level 34.8 ± 3.1 mmol/mol [5.4 ± 0.3%], body fat 31.8 ± 8.2%) completed all four trial arms. Compared with SIT (89.4 ± 6.8 mg/dL), 8-h mean glucose was lower in all other conditions (p < 0.05) and this was statistically significant compared with WALK (86.3 ± 5.2 mg/dL; p = 0.034). Two-hour postprandial glucose after breakfast was approximately 7% lower for WALK compared with SIT (p = 0.002). Furthermore, significant time × condition effects on HRV parameters favouring light-intensity walking were observed (p < 0.001). Replacement and interruption of prolonged sitting with light-intensity walking showed a significant blood glucose-lowering effect and improved HRV during an 8-h work environment in young adults with overweight and obesity.

Physiological movements during sleep in healthy adults across all ages: a video-polysomnographic analysis of non-codified movements reveals sex differences and distinct motor patterns.

To define sleep-related movements in healthy adults according to sex and age. Sleep-related movements from 50 video-polysomnography (vPSG) recordings of 27 men and 23 women, from 20 to 70 years old, were classified according to International classification of sleep disorders (ICSD-3-TR) and American Academy of Sleep Medicine (AASM) criteria (codified movements); the remaining movements (non-codified movements) were described according to type (elementary movements-EMs or complex movements-CMs), topography (focal, segmental, multifocal or generalized) and, if present, were assigned to motor patterns (MPs). Of 4057 movements analyzed, 54.6% (2216/4057) were non-codified (1861 CMs, 355 EMs) and 1841 were codified. CMs were mainly generalized (70%) while EMs were multifocal (40%) or focal (30%). The median movement index (MI; movement/hour) was 11 and the median duration was 4 seconds. MI decreased from stages N1/REM > N2 > N3; men showed a higher MI. An MP was assigned to 2204 codified and non-codified movements, mainly stretching (50%) and scratching (30%). Stretching increased in REM sleep while food-carrying behaviors increased in N2. Men showed more food-carrying behaviors, changes of body positions, and comfort movements while stretching was more common in women. Younger participants exhibited more food-carrying behaviors, while scratching and stretching were more prevalent in the middle-aged group. Older participants showed more changes in body positions and comfort movements. In total, 54.6% of sleep-related movements in healthy participants were non-codified and characterized by motor sequences that can configure MPs. Our comprehensive classification method allows a detailed description of the physiological movements underlying differential motor control during sleep stages influenced by age and sex.

Effect of Body Position Changes on Endotracheal Tube Cuff Pressure Measurements for Mechanically Ventilated Patients

Effect of Body Position Changes on Endotracheal Tube Cuff Pressure Measurements for Mechanically Ventilated Patients

FOT Technique Applied for Monitoring of COVID-19 Pneumonia Reveals Small Airways Involvement.

The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional character of hypoxia. We hypothesize that such effects could be explained by the closure of small airways. To prove the hypothesis, we evaluated the patency of small airways in 30 oxygen-dependent, spontaneously breathing patients with SARS-CoV-2 pneumonia during their hospital stay using the FOT method and then compared the results with data obtained three months later. During the acute period, total resistance (R5) and peripheral resistance (R5-20) rose above the upper limit of normal (ULN) in 28% and 50% of all patients, respectively. Reactance indices X5, AX and Fres exceeded ULN in 55%, 68% and 66% of cases. Significant correlations were observed between PaO2/FiO2, the time spent in the hospital and R5, X5, AX and Fres. After 3 months, 18 patients were re-examined. During the hospital stay, 11 of them had risen above the upper limit of normal (ULN), for both resistance (R5-20) and reactance (X5, AX) values. Three months later, ULN for R5-20 was exceeded in only four individuals, but ULN for X5 and AX was exceeded in five individuals. Lung function examination revealed a combined restrictive/obstructive ventilatory failure and reduced CO transfer factor. We interpret these changes as lung tissue remodeling due to the process of fibrosis. We conclude that during acute period of SARS-CoV-2 pneumonia, dilated pulmonary blood vessels and parenchymal oedema induce functional closure of small airways, which in turn induce atelectasis with pulmonary right-to-left shunting, followed by the resulting hypoxemia.

Speed of heart rate changes during postural provocations in children and adolescents

Heart rate is under constant autonomic influence but the development of the influence in children is not fully understood. Continuous electrocardiograms were obtained in 1045 healthy school-age children (550 females) during postural provocations with body position changes between supine, sitting, standing, supine, standing, sitting and supine (in this order), 10 min in each position with position changes within 20 s. Heart rate was measured in each position and speed of heart rate changes between positions were assessed by regressions of rates versus timing of individual cardiac cycles. Supine heart rate was gradually decreasing with age: 82.32 ± 9.92, 74.33 ± 9.79, 67.43 ± 9.45 beats per minute (bpm) in tertile age groups < 11, 11–15, > 15 years, respectively (p < 0.0001), with no significant sex difference. Averaged speed of heart rate changes differed little between sexes and age groups but was significantly faster during rate deceleration than acceleration (e.g., supine ↔ standing: 2.99 ± 1.02 vs. 2.57 ± 0.68 bpm/s, p < 0.0001). The study suggests that in children, vagal heart rate control does not noticeably change between ages of approximately 6–19 years. The gradual resting heart rate decrease during childhood and adolescence is likely caused by lowering of cardiac sympathetic influence from sympathetic overdrive in small children to adult-like sympatho-vagal balance in older adolescents.