Effect Of Body Position Research Articles

The effect of hand and body position on chest compression quality and rescuer fatigue in prone cardiopulmonary resuscitation

AimThis study aimed to compare the quality of compressions in supine cardiopulmonary resuscitation (CPR) and prone CPR by performing chest compressions on a manikin. Evaluating the effect of prone CPR using different hand and body position on the quality of manual chest compressions and fatigue of participants. MethodsAfter completing 2 min of chest compression in the supine position (Supine Group), 25 participants randomly performed three sets of 2-minutes chest compressions on a prone position manikin. Stand + hands overlapped Group: participants stood beside the patient bed with their hands overlapped and placed on the posterior segment of the thoracic spine between the scapulae, Straddle + hands separated Group: participants straddled the patient bed with their hands placed above the scapulae on both sides at the mid-chest level, and Straddle + hands overlapped Group: participants straddled the patient bed with their hands overlapping on the posterior segment of the thoracic spine between the scapulae. Subsequently, the quality of chest compressions and participants fatigue were assessed. ResultsChest compression depth ratio and mean chest compression depth (MCCD) were worse in the three prone CPR groups (Stand + hands overlapped Group: 0.0(0.0,15.6) %, 39.8 ± 1.3 mm; Straddle + hands separated Group: 1.4(0.0,11.7) %, 42.4 ± 1.2 mm; Straddle + hands overlapped Group: 0.0(0.0,9.2) %, 40.9 ± 1.2 mm) than in the Supine group (87.1(68.1,94.0) %; p < 0.001, 52.4 ± 0.4 mm; p < 0.001). In the three prone CPR groups, Straddle + hands separated Group had the greatest MCCD, lowest changes in heart rate (p = 0.018) and lowest changes in RPE scores (p < 0.001). There were no significant differences between the four groups in terms of mean chest compression rate, accurate chest compression rate ratio, or correct recoil ratio. ConclusionThis simulation-based study showed that the quality of chest compressions was worse in the prone position than in the supine position. When prone chest compressions were performed using different hand and body position, prone CPR performed by a participant straddling a hospital bed with hands placed above the scapula on either side at the mid-chest level provided higher-quality chest compressions and lower rescuer fatigue.

Effects of head gaze and body position on attention in real-world scenes.

Effects of head gaze and body position on attention in real-world scenes.

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.

The Influence of Body Position on the Resting Motor Threshold of Posterior Root-Muscle Reflexes Evoked via Transcutaneous Spinal Cord Stimulation.

Background: Thoracolumbar transcutaneous spinal cord stimulation (tSCS) non-invasively evokes posterior root-muscle reflexes (PRMR) with the aim of neuromodulating sensorimotor function following spinal cord injury. Research is still in its infancy regarding the effect of body position on the nature of these spinally evoked responses. Therefore, the aim of this study was to investigate the influence of body position on the nature of PRMR responses during tSCS. Methods: A total of 11 (6M, 5F) participants completed a full PRMR recruitment curve from 10 ma up to 120 ma (10 ma increments) at the T11/12 intervertebral space using a singular 3.2 cm diameter cathode. At each intensity, three paired pulses (50 ms inter-pulse interval), followed by three singular pulses with a six-second delay were applied in each body position (supine, supine 90-90, sitting and standing) in a randomised order. The PRMR responses in lower limb muscles were recorded using wireless electromyographic sensors placed on the Soleus, Tibialis Anterior, Rectus Femoris and Bicep Femoris long head. A two-way (body position × muscle) repeated measures analysis of variance was used to investigate the effect of body position on PRMR-evoked responses. Results: There was a significant main effect of body position on PRMR resting motor threshold (RMT) (p < 0.001), first response peak-to-peak amplitude (p = 0.003) and percentage post-activation depression (%PAD) (p = 0.012). Sitting had significantly higher RMT and significantly lower first response peak-to-peak amplitudes compared to all other positions, but significant differences in %PAD were only detectible between supine and standing. Conclusions: Body position influences the nature of PRMR-evoked responses during tSCS.

The Effects of Body Position and Cadence on Energy Expenditure, Exercise Intensity, and Substrate Utilization During Indoor Cycling

The Effects of Body Position and Cadence on Energy Expenditure, Exercise Intensity, and Substrate Utilization During Indoor Cycling

Effect of body position on transesophageal atrial pacing in dogs

ObjectiveTo evaluate the effect of body position on transesophageal atrial pacing (TEAP) in dogs. Study designProspective, experimental trial. AnimalsA total of eight mixed-breed dogs, median body mass 25 kg (range 11–31 kg). MethodsTEAP was performed using a 6 Fr (2 mm) pacing catheter introduced transorally and positioned in the lower esophagus in left lateral recumbency. The catheter was withdrawn in 5 mm increments until successful TEAP. The minimum pacing threshold (MPT) was determined at each 5 mm increment until atrial capture could not be achieved at a maximal pulse amplitude of 40 mA. The zone of capture (ZOC) was the total distance over which TEAP was achieved. The same process was repeated in right lateral, ventral and dorsal recumbency. A linear mixed model was used to assess the impact of body position on TEAP and ZOC. ResultsTEAP was achieved in all body positions. There was significant random effect of individual dogs on ZOC (p = 0.048) but not on MPT (p = 0.109). MPT was 11.56 ± 8.65 mA (mean ± SD), 8.43 ± 2.29 mA, 10.63 ± 6.91 mA and 10 ± 7.44 mA for dorsal, left and right lateral, and ventral recumbency, respectively. ZOC was 5.12 ± 2.08 cm, 6.35 ± 2.41 cm, 5.94 ± 3.23 cm and 5.31 ± 2.2 cm for dorsal, left lateral and right lateral, and ventral recumbency, respectively. Neither ZOC (p = 0.363) nor MPT (p = 0.716) varied significantly between body positions. Conclusions and clinical relevanceTEAP can be performed successfully in all body positions in dogs. Body position did not significantly influence MPT or ZOC values for TEAP. Further studies are needed to compare the efficacy of TEAP with the efficacy of standard pharmacological therapy for management of bradycardia during general anesthesia in dogs.

The Effect of Change Position on Cardiac Function Patterns on Patients with COVID-19 Diagnosis: A Clinical Trial Study.

Various methods are used to treat patients with coronavirus, including drug therapy and alternative and non-invasive therapies Research has been done on the effects of body position on cardiac function in patients with COVID-19 diagnosis. This study was performed on patients admitted with COVID-19 diagnosis. Patients with inclusion criteria were selected based on purpose and entered into the study. They were divided into three groups: Group A patients were placed in a semi-sitting position, group B patients were placed in a tripod position, and group C patients were placed in a prone position. After being placed in the relevant positions at 15 and 60 minutes were measured in terms of heart rate and blood pressure at the mentioned times in the relevant checklist. The results showed that there was no statistically significant difference in heart rate between the three groups before the intervention (P>0.05). In other words, changes in heart rate over time between the three groups (in several measurements) were statistically significant (P<0.05). Regarding Systolic Blood Pressure (SBP) and Diastolic Blood pressure patterns, the results showed that the three position groups was not statistically different before and 15 and 60 minutes after the intervention (P>0.05). According to the results, it can be concluded that placing the patient in all three positions of the tripod, prone and semi-sitting can be effective in improving the patient's heart rate pattern and lead to improving the patient's clinical condition.

The effect of body position, leg dominance, and automatic releasing mechanism on quadriceps muscle tone assessed by Pendulum Test in able-bodied persons.

<p>Quadriceps femoris muscle spasticity is commonly measured by the Wartenberg pendulum test. It is generally assumed that lower values of the number of swings of the leg and lower relaxation indexes are associated with higher muscle tone and more spasticity. Still, there is incoherence regarding the test&rsquo;s applications with various body positions and starting mechanisms. This study aims to investigate the influence of body position, leg dominance, and automatic leg-releasing mechanism on muscle tone measured by pendulum test in healthy population whose muscle tone is often compared to the spastic muscle tone of patients with neurologic disorders.&nbsp;</p>. <p>15 healthy adults (age: 19-32 years, 9 males, 6 females) participated in this study. A Zebris 3D ultrasound-based motion analysis system was used to record kinematic data during the pendulum test. The number of swings of the leg and the relaxation index were computed from the collected data. The pendulum test was completed in eight conditions: in supine and semi-supine positions on the dominant and non-dominant leg separately and with investigator-release and automata-release mechanisms. Paired t-tests and Wilcoxon test with the significance level of .05 were applied in comparison of pairs of the pendulum test condition.</p>. <p>1) Applying automata-release mode, in the non-dominant leg the number of swings (p=0.03) and the relaxation index (p&lt;0.001) were significantly higher in semi-supine than in supine position. 2) The non-dominant leg had significantly more swings than the dominant leg in both body positions with automata-release mode (p=0.009, p&lt;0.001). In investigator-release mode this occurred in supine position (p&lt;0.001). 3). Regarding the number of swings in investigator-release versus automata-release mode, no significant differences were found in any test condition, but the relaxation index showed significant difference for the non-dominant leg (p=0.01, p=0.009). 4) The values of the relaxation index didn&rsquo;t support in all test conditions the results what the number of swings provided about the muscle tone. In automata-release mode, the dominant leg has a lower number of swings and a higher relaxation index than the non-dominant leg.</p>. <p>The effect of body position on the quadriceps muscle tone can be assessed by applying the pendulum test with an automatic leg-releasing mechanism even when the application of conventional investigator-release mode does not show a significant effect. The pendulum test is more sensitive to assess spasticity with automatic-release than with investigator-release mode.&nbsp;</p>.

Body Positions Alter Hemodynamics and Respiration in Healthy Adults: A Systematic Review and Meta-Analysis

Objective Different body positions can exert both positive and negative physiological effects on hemodynamics and respiration. This study aims to conduct a literature review and examine hemodynamic and respiratory alterations to different body positions.Methods The study protocol was registered with the International Prospective Registry of Systematic Reviews (register no. CRD42021291464). Two independent reviewers evaluated the methodological quality of all included studies using the Down and Black checklist, while the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach. The overall effects of different body positions were reported from random effects meta-analysis.Results Three studies with low risk of bias and ten with high risk of bias met the eligibility criteria. The supine resulted in the highest cardiac output compared to the 70 deg head-up tilt, sitting, and standing positions (very low- to moderate-quality evidences) and the lowest systemic vascular resistance compared to the 70 deg head-up tilt and standing positions (moderate-quality evidence). Additionally, the supine was associated with the highest total respiratory resistance compared to the 70 deg head-up tilt, left lateral, and standing positions (very low-to moderate-quality evidence) and higher alveolar ventilation than the prone (low-quality evidence).Conclusions The supine position has the most positive association with hemodynamic variables, resulting in the highest cardiac output and the lowest systemic vascular resistance. The upright positions (70 deg head-up tilt and standing positions) has the most positive association with the respiratory variables, resulting in the lowest total respiratory resistance.

Exploring the Relative Effects of Body Position and Locomotion Method on Presence and Cybersickness when Navigating a Virtual Environment

The primary goals of this research are to strengthen the understanding of the mechanisms underlying presence and cybersickness in relation to the body position and locomotion method when navigating a virtual environment (VE). In this regard, we compared two body positions (standing and sitting) and four locomotion methods (steering + embodied control [EC], steering + instrumental control [IC], teleportation + EC, and teleportation + IC) to examine the association between body position, locomotion method, presence, and cybersickness in VR. The results of a two-way ANOVA revealed a main effect of locomotion method on presence, with the sense of presence significantly lower for the steering + IC condition. However, there was no main effect of body position on presence, nor was there an interaction between body position and locomotion method. For cybersickness, nonparametric tests were used due to non-normality. The results of Mann-Whitney U tests indicated a statistically significant effect of body position on cybersickness. In particular, the level of cybersickness was significantly higher for a standing position than for a sitting position. In addition, the results of Kruskal-Wallis tests revealed that the locomotion method had a meaningful effect on cybersickness, with participants in the steering conditions feeling stronger symptoms of cybersickness than those in the teleportation conditions. Overall, this study confirmed the relationship between body position, locomotion method, presence, and cybersickness when navigating a VE.

Effect of body position on ventilation distribution in healthy newborn infants: an observational study

ObjectivesNewborn infants have unique respiratory physiology compared with older children and adults due to their lungs’ structural and functional immaturity and highly compliant chest wall. To date, ventilation distribution has...

Effects of Body Position on Cochlear Function in Infants: An Otoacoustic Emission Study.

Otoacoustic Emission (OAE) is frequently recorded in various body positions for infants. However, little is available about whether these deviations will produce non-pathological effects on the clinical results. The current study assessed body position's effect on infants' inner ear function. Sixty normally hearing infants participated in an analytical cross-sectional study. Distortion-product OAEs (DPOAEs) were measured in the supine, side-lying, and upright positions. The DPOAE amplitude and signal-to-noise ratio (SNR) were recorded across the 1500 to 6000Hz range. The mean DPOAE amplitude and SNR values were significantly greater in the upright position than supine and side-lying positions (p < 0.05). These differences were more pronounced in the 3000 to 6000Hz range. The effects of gender and ear asymmetry on DPOAEs were not statistically significant. Our findings suggested that the upright position could be regarded as the best position for assessing DPOAEs in infants.

Effect of body position on peak expiratory flow during mechanical insufflation–exsufflation in people with cervical spinal cord injury: a pilot study

This prospective pilot study investigated the influence of body position on peak cough flow (PCF) during mechanical insufflation–exsufflation (MI-E) treatment in people with tetraplegia. Fifteen participants with cervical spinal cord injury (C-SCI) were randomized into two groups, which differed in the starting position, that is, the patients were either supine or reclined. Four sessions of MI-E in alternating positions with each session comprising three different maneuvers: five voluntary coughs, five MI-E-assisted coughs, and five MI-E-assisted with manual thrusts were performed with continuous airflow measurement reporting PCF from every cough. PCF was associated with the application maneuvers, total insufflation volume (TIV), and interaction between position and maneuvers but not with the application position. The estimated mean PCF was 1.808, 3.529, and 3.925 L/s when supine and 1.672, 3.598, and 3.909 L/s when reclined from voluntary cough, MI-E, and MI-E with manual thrust, respectively. The estimated PCF change compared to voluntary cough was 1.721 (95% CI, 1.603–1.838) L/s from the combined MI-E and 2.116 (95% CI, 2.005–2.228) L/s from the MI-E with manual thrust, calculated from the linear mixed-model analysis. PCF moderately correlated with TIV (R2 = 0.64). Therefore, either position can be used for C-SCI patients as long as MI-E can be performed with manual thrust and sufficient TIV is provided.

The Effect Of Dıfferent Body Posıtıons On Calf Blood Pressure: A Cross-Sectional Study

The calf area is an alternative measurement site when blood pressure cannot be measured at the arm. To determine the effects of different body positions on calf blood pressure readings in healthy young students. A total of 100 healthy young students who agreed to participate in the study were randomly selected. The study was carried out in Aydın Adnan Menderes University Nursing Faculty. In all participants, blood pressure was measured in four positions: supine, prone, right lateral, and left lateral recumbent. All measurements were performed three times at 1-min intervals, and the results were compared. There was no statistically significant difference between the systolic and diastolic blood pressure measurements in the supine and prone positions (p&gt;0.05). The systolic blood pressure value was significantly lower in the left lateral recumbent position than in the other positions (p

The Effects of Body Positions and Abduction Angles on Shoulder Muscle Activity Patterns during External Rotation Exercises.

Excess and repetitive glenohumeral external rotation (ER) is at a higher risk for shoulder injuries, which occurs frequently in professional sports and specific occupations. Current rehabilitation programs emphasize selective targeting of muscle activity, which can help restore dysfunctional muscle imbalances or prevent injuries. However, the impact of different body postures on GH muscle activity during ER exercises has not been fully understood. Therefore, the purpose of this study was to investigate shoulder EMG activity for different body positions and humeral abduction angles during ER exercises. Twenty-three healthy young men (age: 22.3 ± 2.3, height: 175.75 ± 4.02, mass: 75.37 ± 9.14) participated in this study. Surface Electromyography was recorded from seven shoulder muscles: upper trapezius, lower trapezius, serratus anterior, infraspinatus, and deltoid. Six ER exercises: three postures (sitting, supine lying, and prone lying) and two abduction angles (ABD; 45° and 90°) were tested using an isokinetic dynamometer. During a sitting position, the lower trapezius/upper trapezius muscle activity ratios were significantly increased for sitting compared to supine lying and prone lying (p < 0.001, p = 0.004). Serratus anterior/upper trapezius co-contraction indices were significantly increased for 90° than 45° ABD (p < 0.001). These findings can provide insight into new training programs aimed at restoring GH muscle imbalances.

Impacts of body positions on the geniohyoid muscle contraction and swallowing difficulty in healthy adults.

Body positions affect swallowing and gastroesophageal reflux. Swallowing impairment is one of the main causes of aspiration pneumonia. To prevent pneumonia, evaluation of body positions on gastroesophageal reflux recommended 30 degrees or higher semi-recumbent positions. The geniohypoid muscle and tongue play central roles in swallowing. However, the effects of body positions on contracting rates in the geniohyoid muscle and tongue pressure are unclear. Moreover, correlations between geniohyoid muscle contracting rates and subjective swallowing difficulties are unclear. This study aimed to identify the proper body positions on contracting rates in the geniohyoid muscle, tongue pressure, and subjective swallowing difficulties. Twenty healthy adults swallowed 15- or 50 ml of water at 90 degrees sitting, 60- and 30 degrees semi-recumbent, and 0 degrees supine positions. We scored the subjective swallowing difficulties and measured the tongue pressure and the number of swallows. An ultrasound evaluated the geniohyoid muscle size and contracting rates. At sitting and 60 degrees semi-recumbent positions, the geniohyoid muscle showed greter contracting rates than at 30 degrees semi-recumbent and supine postions (P < 0.05), which resulted in easier swalloiwng. Greater tongue pressure was weakly correlated with fewer swallows (r = -0.339, P = 0.002), whereas the body positions did not affect. Considering swallowing and gastroesophageal reflux together, a trunk angle of 60 degrees or more might be beneficial for reducing the risk of aspiration.

IMPACT OF BODY POSITION ON ARTERIAL STIFFNESS OF ELASTIC AND MUSCULAR ARTERIES

Objective: Arterial stiffness is assessed through determination of pulse wave velocity (PWV) over an arterial segment of interest. Measurements are traditionally done in a supine position, which is both practical for high quality arterial pressure wave recordings, and the stability of pressure exerted on the arterial wall along the arterial path. The aim of this project was to study the effect of body position on the stiffness of elastic and muscular arteries. Design and method: This study was conducted with healthy adults. Aortic (cf-PWV) and brachial stiffness (CR-PWV) were repeatedly measured in three different positions (supine, 30̊ and 60̊) using the Complior Analyse. Brachial blood pressure (Mobil-O-graph) was also measured in each position. Generalized Estimating Equations in SPSS were performed to establish changes of PWV between positions. Results: In 23 healthy individuals (65% female, mean age of 36±15 years, and mean systolic (SBP) and diastolic blood pressures (DBP) of 120±2 mmHg and 76±2 mmHg, respectively), CF-PWV increased progressively with body tilting (8.7 (CI95% = 8.0–9.4) m/s supine, 9.4 (CI95% = 8.8–10.0) m/s at 30̊ and 9.5 (CI95% = 8.8–10.1) m/s at 60̊) (p&lt;0.001)). On the other hand, CR-PWV didn’t significantly change with body tilting (8.7 (CI95% = 8.0–9.3) m/s supine, 8.8 (CI95% = 8.0–9.6) m/s at 30̊ and 8.9 (CI95% = 8.1–9.6) m/s at 60̊). SBP didn’t significantly change with body tilting (120 (CI95% = 116-125) mmHg supine, 121 (CI95% = 116–125) mmHg at 30̊ and 122 (CI95% = 117-126) mmHg at 60̊), while DBP increased (76 (CI95% = 71-80) mmHg supine, 78 (CI95% = 73–83) mmHg at 30̊ (p&lt;0.022) and 81 (CI95% = 77-85) mmHg at 60̊ (p&lt;0.001)). Heart rate also increased with body tilting (68 (CI95% = 64–72) BPM supine, 69 (CI95% = 65–73) BPM at 30̊ and 77 (CI95% = 72–82) BPM at 60̊ (p&lt;0.001)). Conclusions: These preliminary results show that elastic and muscular arteries tend to react differently to body positions, without significant changes in arterial stiffness of medium muscular arteries in the arm.

0525 Effect of Body Position and Sleep State on Obstructive Respiratory Events Distribution in Children with Down syndrome

Abstract Introduction The influence of body position and sleep state on obstructive respiratory events distribution in children with Down syndrome (DS) need further studies. Methods This was a single center, retrospective study that included children younger than 18 years old with DS who were evaluated for suspected sleep disordered breathing and underwent a full overnight polysomnography in an academic sleep disorders center over a period of 10 years. DS children with Obstructive apnea hypopnea index (OAHI) ≥ 1.5 were included in this study. Total OAHI, apnea hypopnea index (AHI) in different body positions and in different sleep stages including rapid eye movement (REM) and Non-REM (NREM) sleep were collected. Results A total of 158 children with DS met the inclusion criteria. The median age was 5 years (IQR 8.0---), 53.2% were male with a median BMI z-score of 1.2. Median times (%) spent in REM and NREM sleep were 17 % and 83% respectively. Median times (minutes) spent in different body positions were supine 194.1, left side 53.5, right side 39 and prone 32. The overall median OAHI was 7.6, respiratory obstructive events were more common in REM sleep and in supine position. The median REM obstructive AHI was 20 events per hour (IQR: 10.1-34.5), whereas the median NREM AHI was 5.2 events per hour (IQR: 2.4-15 p &amp;lt; 0.0001). Similarly, supine obstructive AHI was 9.4 (IQR-4.15 – 24.1) and off supine AHI was 2.4 (IQR 0-8.9 p &amp;lt; 0.0001). Only 24 out of 158 subjects had NREM predominant OSA. Age was a significant predictor of NREM predominant OSA (P= 0.012) compared to other factors such as gender, race, BMI, tonsillar grade, hypothyroidism and congenital heart disease. For every one year increase in age, the odds of having NREM predominant OSA was 14% higher than having REM predominant OSA. Conclusion Obstructive respiratory events in children with DS occur predominantly in REM sleep and in supine position. Non-REM predominant distribution of respiratory events was seen in older children with DS. Support (if any)

0526 Effect of Body Position and Sleep State on Sleep Disordered Breathing Distribution in Infants Ages 6 to 12 months

Abstract Introduction The effect of body position and sleep state on events distribution in infants ages 6 to 12 months needs further study. We aimed to study this distribution and determine the difference of body position in infants with and without sleep disordered breathing. Methods This was a single center, retrospective study that included infants ages 6 to 12 months who were evaluated for suspected sleep disordered breathing and underwent a full overnight polysomnography in an academic sleep disorders center over a period of 10 years. Infants with ages 6 to 12 months with obstructive sleep apnea hypopnea index (OAHI) and central apnea index (CAI) ≥ 1 (sleep disordered breathing [SDB] group) were compared with infants with normal AHI who represented the control group (CG). Total OAHI, CAI, apnea hypopnea index (AHI) in different body positions, rapid eye movement (REM), and Non-REM sleep were collected. Results A total of 36 infants had SDB and 18 infants had normal AHI. The median age was not significantly different between both groups with a median age of 10 months (IQR 7.75-11) in SDB group and 8.5 months in CG (IQR 7.25- 10.00) (p=0.258). Male sex was predominant in both groups (58.3% in SDB group and 61.1% in CG). There were no significant differences between both groups in the BMI, median total sleep time, REM% sleep time, and Non-REM% sleep time. The supine sleep time in the SDB group [258.90 minutes (IQR 149.35-381.25)] was significantly higher than the supine sleep time in the CG [165.90 minutes (IQR 54.55 to 285.05)] (p=0.035). In the SDB group, REM AHI [8.55 (IQR 5.02 – 15.25] was significantly higher than Non-REM AHI [0.50 (IQR 0.30-1.20)] (p&amp;lt; 0.001). In the SDB group, there were no significant differences in the supine vs. off-supine distribution of respiratory events. Conclusion Obstructive and central respiratory events in infants ages 6 to 12 months occurred predominantly in REM sleep compared to Non-REM sleep. Infants with SDB significantly spent more time in supine position when compared to infants without SDB but the respiratory events distribution in infants with SDB did not have a significant positional distribution. Support (if any)

Commentary: The impact of yoga practice on glaucoma.

Yoga is the most popular form of complementary therapy being practiced to maintain one’s physical and mental wellbeing. While yoga traditionally comprises advice for ethical lifestyle and spiritual practice, it is most often associated with physical postures (asanas), breathing techniques (pranayama), and meditation (dhyana). While these exercises are routinely safe, there are risks involved for certain patients including those suffering from or at risk of glaucoma. The effects of yoga on intraocular pressure (IOP) have been found to be bidirectional, and the exact mechanisms are not yet fully understood. The authors have reviewed literature to study the effect of yoga on IOP and glaucoma. They have observed a reduction of IOP in patients of glaucoma through Jyoti tratak (candle meditation) and slow yoga breathing exercises and a rapid increase in IOP immediately after head-down posture yoga.[1] Tratak kriya is said to lead to contraction and relaxation of ciliary muscles, which may possibly increase the aqueous humor outflow and subsequently decrease the IOP.[2] Dada et al.[3] have evaluated the effect of yoga and meditation on IOP, quality of life, stress markers, neurotrophins, and gene expression in patients with primary open-angle glaucoma and found an improvement in all parameters. On the other hand, progressive glaucomatous optic neuropathy and field loss in patients who regularly practiced Sirsasana (Headstand) has also been identified.[1,4,5] Four yogasanas [Adho Mukha Savasana (downward-facing dog), Uttanasana (standing forward bend), Halasana (plough pose), and Viparita Karani (legs-up-the-wall)] showed a 20–73.7% increase in IOP in all study subjects.[1] Yoga with head-down positions was associated with a rapid rise in IOP in glaucoma and healthy eyes and with the body vertical, with a doubling of the IOP, remaining elevated as long as the position was maintained.[1] Mani Baskaran et al.[6] observed a twofold increase in IOP during Sirsasana, which was maintained during the posture in all age groups irrespective of their ocular characteristics. Valsalva maneuver is known to affect IOP; so it is expected that breath-holding yogic exercises are likely to cause IOP elevation. Forced unilateral nostril breathing has also been observed to affect IOP significantly.[7] Rakstyte et al.[8] studied an impact on IOP before, during, and after Matsyasana (fish yoga pose) and found an increased IOP in head- down position which returns to the initial value shortly after. A case series by Mehrdad Malihi et al.[9] to study the effect of different body and head positions on IOP shows a lower measurement while sitting with a neutral neck position and a rise in IOP in all other positions. Acute angle-closure glaucoma attacks often precipitated by prone-position yoga exercises suggest that this position probably increases pupillary block in “at risk” eyes by causing the lens to fall onto the iris, which has been the principle of the prone provocative test for decades. Certain questions, however, remain unanswered. It is unclear whether yoga has any sustained effects on the IOP and optic nerve. Further research is needed to fully comprehend the mechanisms by which yoga exerts its effects and determine the types, optimal duration, and frequency of yoga practice for glaucoma patients. Future studies are also warranted to ascertain whether yoga-associated IOP changes are associated with parallel changes in perimetry and nerve fiber thickness and changes in cerebrospinal fluid pressure, blood pressure in lamina cribrosa capillaries, and the ocular blood flow. It is difficult to establish direct causality between different yogic postures and glaucomatous progression, but in patients with pre-existing glaucomatous optic neuropathy, dramatic changes in IOP can definitely be harmful. Inquiring about the practice of yoga in cases of unexplained progression despite an apparently well-controlled IOP can, therefore, be an important consideration. Relaxation and meditative aspects of yoga may help to reduce stress and improve the overall well-being of an individual which can be indirectly beneficial. The key is to “keep the head above the heart at all times.” It is also important to note that yoga should not replace traditional glaucoma treatment but rather be practiced/advised as a complementary therapy and glaucoma patients should consult their healthcare provider before beginning any new exercise or relaxation program, including yoga.