Effect Of Body Position Research Articles

Effects of Various Body Positions on Arterial Stiffness as Assessed by Pulse Wave Velocity

BackgroundStandard measurements of arterial stiffness via pulse wave velocity (PWV) are conducted with participants in the supine position. When participants cannot tolerate supine position for prolonged procedure time (e.g., low back pain), accommodations may be made to tilt the bed up or bend the knees (i.e., Fowler’s positions). Moreover, a new testing device (Vicorder) that uses neck oscillometric cuff requires upper body tilt to avoid jugular vein interference on the recorded carotid pulse. Accordingly, this study aimed to investigate the effect of varying body positions on arterial stiffness measured via PWV.METHODSA total of 70 adults (43 women) varying widely in age (19‐66 years old), race/ethnicity (41% non‐white), and medical conditions were studied. Both carotid‐femoral PWV (cfPWV) and brachial‐ankle PWV (baPWV) were measured using two different testing devices (Omron vp1000plus and Vicorder) with participants in the reference supine (0º) position, 10º, 20º, 30º, and 40º upper body tilted‐up positions with and without knee flexion. The presence of jugular vein interference was documented visually on the oscillometric arterial waveforms at each body angle.RESULTSBoth cfPWV and baPWV measured at 10º upper body tilt‐up position were not significantly different from those assessed at the reference supine (0º) position. Upper body angle of 20º or greater produced PWVs that were significantly and gradually elevated (p<0.01). The magnitude of elevations in cfPWV were 7% (95% CI [6‐11%]) at 20º and 15% (95% CI [11‐18%]) at 40º while the elevations in baPWV were 8% (95% CI [6‐10%]) at 10º and 33% (95% CI [30‐36%]) at 40º compared with the supine (0º) position. Knee flexion did not alter cfPWV compared with straight knees whereas knee flexion decreased baPWV at the same upper body angle (p<0.05). Jugular vein interference in the Vicorder device appeared on 78% of participants in the supine (0º) position and gradually decreased as the upper body angle increased, resulting in 7% of the participants at 30º angle. The appearance of Jugular vein contamination was not affected by knee flexion.CONCLUSIONArterial stiffness as assessed by cfPWV and baPWV increased gradually and significantly by the use of semi‐Fowler position of ≥20º whereas bending knees at each angle decreased baPWV, but did not appear to influence cfPWV. Our present findings highlight the difficulty in comparing two different devices that are supposed to reflect the same arterial property.

Why upright standing men urinate more efficiently than in supine position: A morphological analysis with real-time magnetic resonance imaging.

Few studies have examined the effects of body position on urination efficiency morphologically. We aimed to dissect out the anatomical changes of pelvic organs during urination in the upright and supine positions by a real-time magnetic resonance imaging (rtMRI) system. Thirteen healthy male volunteers aged 26-60 years were included in the study. The sagittal real-time two-dimensional images were taken to evaluate urinary efficiency, along with change in six morphological indices at the time of storage and the beginning of voiding, in both upright ant supine positions. Urination was more efficient in upright position than in supine position, as expressed by higher average rate of bladder emptying (9.9 ± 4.2 vs. 6.8 ± 2.9 ml/s, p < 0.05) and also by fewer participants showing significant residual urine (1/13 vs. 7/13, p < 0.05). At the onset of voiding in standing position, the levator ani (LA) muscle moves downward and backward followed by descent of the bladder neck and rotation of the prostate around the symphysis. Such changes were expressed by two morphological indices. One was posterior vesicourethral angle at the start of voiding, 152 ± 7 versus 140 ± 1 in upright and supine position (p < 0.05). The other index was the change in angle between the LA line and pubo-coccygeal line in upright and supine position, 9.4 ± 9.9 versus 1.6 ± 7.9 before voiding (p < 0.05) and 30.2 ± 14.0 versus 17.3 ± 12.9 after the start of voiding (p < 0.05). The dynamic relaxation of LA seemed to be a key movement that enables more efficient urination in standing position than in supine position.

The effect of body position while coughing on the airborne transmission of pathogens

Given the recent acceptance of the central role of airborne transmission for SARS-CoV-2, increased attention has been paid to the dispersion of respiratory droplets in different scenarios. Studies including numerical simulations have been conducted on methods for breaking the chains of transmission. Here, we present the first such study on the impact of body position while coughing on the dispersion of respiratory droplets. Four scenarios are examined, including normal standing, bending the head at different angles, coughing into the elbow in still air, and a gentle breeze from the front and behind. The model showed that an uncovered cough is dangerous and causes many droplets to enter the environment, posing a cross-contamination threat to the others. Droplets with an initial diameter smaller than 62.5 μm remain suspended in windless air for more than 3 min. In the presence of wind, these droplets move with the wind flow and may travel long distances greater than 3.5 m. The model showed that covering the mouth with the elbow while coughing is clearly the best strategy for reducing airborne transmission of exhaled pathogens. About 62% of the initial number of droplets deposit on the cougher's elbow immediately after the cough and have no chance of spreading through the air in both windless and windy conditions. Covering the cough in windless or light breeze conditions also causes the upward thermal plume around the body to expel many small droplets.

TO STUDY THE EFFECT OF BODY POSITIONS ON OXYGEN SATURATION AND PEFR IN POST CORONARY ARTERY BYPASS GRAFT PATIENTS

CABG is the most common type of heart surgery. Reduced pulmonary functions and oxygen saturation are common postoperative complications. Body positions tends to show effect on peak expiratory ow rate and oxygen saturation .so, in this study we have observed effects of different body positions in values of PEFR and oxygen saturation for better recovery from post-operative complications. Objective was to evaluate the differences in values of PEFR and oxygen saturation in different body positions (supine, erect sitting, three quarter sitting, standing). Method: the study design was observational cross-sectional study. 30 subjects of age group 40-70 years were selected through random sampling technique. PEFR and oxygen saturation values were checked on post-operative day 3.subjects were allocated each position for 15 min and then values were recorded. the study results Results: indicated that standing position shows highest PEFR value (340.67 liters/min) and best oxygen saturation (97.53), supine position shows lowest PEFR value (183.00 liters/min) and lowest oxygen saturation (93.43). Difference in between the body positions three quarter sitting, sitting and supine were signicant (p&lt;0.005) when compared with standing. The study concluded that standing position leads to highest PEFR a Conclusion: nd oxygen saturation value and supine position leads to lowest value of PEFR and oxygen saturation. So standing should be considered as best therapeutic position.

Visuospatial orientation: Differential effects of head and body positions

To orientate in space, the brain must integrate sensory information that encodes the position of the body with the visual cues from the surrounding environment. In this process, the extent of reliance on visual information is known as the visual dependence. Here, we asked whether the relative positions of the head and body can modulate such visual dependence (VD). We used the effect of optokinetic stimulation (30°/s) on subjective visual vertical (SVV) to quantify VD as the average optokinetic-induced SVV bias in clockwise and counter-clockwise directions. The VD bias was measured in eight subjects with a head-on-body tilt (HBT) where only the head was tilted on the body, and also with a whole-body tilt (WBT) where the head and body were tilted together. The VD bias with HBT of 20° was in the same direction of the head tilt position (left tilt VD −1.35 ± 0.1.2°; right VD 1.60 ± 0.9°), whereas the VD bias with WBT of 20° was in a direction away from the body tilt position (left tilt VD 2.5 ± 1.1°; right tilt VD −2.1 ± 0.9°). These findings show differential effects of relative head and body positions on visual cue integration, a process which could facilitate optimal interaction with the surrounding environment for spatial orientation.

Effects of body position on measurement of respiratory function and cough capacity: Comparison between young and elderly

Effects of body position on measurement of respiratory function and cough capacity: Comparison between young and elderly

Effects of Recording Device, Body Position, Electrode Placement, and Sedation on Electrocardiogram Intervals in Dogs

Effects of Recording Device, Body Position, Electrode Placement, and Sedation on Electrocardiogram Intervals in Dogs

Dominance and prestige: Meta-analytic review of experimentally induced body position effects on behavioral, self-report, and physiological dependent variables.

Dominance and prestige: Meta-analytic review of experimentally induced body position effects on behavioral, self-report, and physiological dependent variables.

Supplemental Material for Dominance and Prestige: Meta-Analytic Review of Experimentally Induced Body Position Effects on Behavioral, Self-Report, and Physiological Dependent Variables

Supplemental Material for Dominance and Prestige: Meta-Analytic Review of Experimentally Induced Body Position Effects on Behavioral, Self-Report, and Physiological Dependent Variables

Prolonged Continuous Monitoring of Regional Lung Function in Infants with Respiratory Failure.

Rationale: Electrical impedance tomography (EIT) allows instantaneous and continuous visualization of regional ventilation and changes in end-expiratory lung volume at the bedside. There is particular interest in using EIT for monitoring in critically ill neonates and young children with respiratory failure. Previous studies have focused only on short-term monitoring in small populations. The feasibility and safety of prolonged monitoring with EIT in neonates and young children have not been demonstrated yet. Objectives: To evaluate the feasibility and safety of long-term EIT monitoring in a routine clinical setting and to describe changes in ventilation distribution and homogeneity over time and with positioning in a multicenter cohort of neonates and young children with respiratory failure. Methods: At four European University hospitals, we conducted an observational study (NCT02962505) on 200 patients with postmenstrual ages (PMA) between 25 weeks and 36 months, at risk for or suffering from respiratory failure. Continuous EIT data were obtained using a novel textile 32-electrode interface and recorded at 48 images/s for up to 72 hours. Clinicians were blinded to EIT images during the recording. EIT parameters and the effects of body position on ventilation distribution were analyzed offline. Results: The average duration of EIT measurements was 53 ± 20 hours. Skin contact impedance was sufficient to allow image reconstruction for valid ventilation analysis during a median of 92% (interquartile range, 77-98%) of examination time. EIT examinations were well tolerated, with minor skin irritations (temporary redness or imprint) occurring in 10% of patients and no moderate or severe adverse events. Higher ventilation amplitude was found in the dorsal and right lung areas when compared with the ventral and left regions, respectively. Prone positioning resulted in an increase in the ventilation-related EIT signal in the dorsal hemithorax, indicating increased ventilation of the dorsal lung areas. Lateral positioning led to a redistribution of ventilation toward the dependent lung in preterm infants and to the nondependent lung in patients with PMA > 37 weeks. Conclusions: EIT allows continuous long-term monitoring of regional lung function in neonates and young children for up to 72 hours with minimal adverse effects. Our study confirmed the presence of posture-dependent changes in ventilation distribution and their dependency on PMA in a large patient cohort. Clinical trial registered with www.clinicaltrials.gov (NCT02962505).

Morphometrics of nuchal ligament in greyhound in different neck and body positions

This study was conducted to describe the morphometrics of nuchal ligament and investigate the effects of different neck and body positions on the nuchal ligament in greyhounds. Nine adult greyhounds cadavers without any locomotion abnormalities were dissected through the neck musculature on the left side to expose the nuchal ligament. Three pins were placed to mark regions of interest on the nuchal ligament: at one cm cranial to the site of origin (the most dorsal point of the spinous process of the first thoracic vertebra), at the midpoint of the nuchal ligament and one cm caudal to the nuchal ligament site of insertion (close to the caudal aspect of the spinous process of the axis). Each cadaver was positioned on a masonite board and placed on a table on the floor in their lateral recumbency and seven different standardized body positions; P1-P7 were mimicked using goniometers and metal wires. Photographs were taken by positioning and fixing the camera above the nuchal ligament region. The length and widths (W1, W2 and W3) of nuchal ligament were measured using Image Pro software (Image-Pro Express version 5.0) on standardized photographs of each of seven different body and neck positions. The length of nuchal ligament in relation to the neutral position (P1) was less (- 7%, p>0·05) in P6 (neck elevated) and increased in all other positions (+1%, p>0·05 for P2, +19%, p<0·05 for P3, +37%, p<0·05 for P4, +1%, p>0·05 for P5, +40%, p<0·05 for P7). Nuchal ligament width at the middle (W2) decreased significantly with P4 (- 26%, p<0·05), and P7 (- 32%, p<0·05). Also, nuchal ligament width at the site of origin (W3) decreased significantly with P4 (- 24%, p < 0·05) and P7 (-35%, p<0·05). These findings reflect the need for clinical and biomechanical studies to describe in-depth the gross anatomy of the nuchal ligament in greyhounds. They suggest that different neck and body positions change the shape, and hence, the function of the nuchal ligament during movement.

The Effects of Body Position on Trochanteric Soft Tissue Thickness-Implications for Predictions of Impact Force and Hip Fracture Risk During Lateral Falls.

Trochanteric soft tissue thickness (TSTT) is a protective factor against fall-related hip fractures. This study's objectives were to determine: (1)the influence of body posture on TSTT and (2)the downstream effects of TSTT on biomechanical model predictions of fall-related impact force (Ffemur) and hip fracture factor of risk. Ultrasound was used to measure TSTT in 45 community-dwelling older adults in standing, supine, and side-lying positions with hip rotation angles of -25°, 0°, and 25°. Supine TSTT (mean [SD] = 5.57 [2.8]cm) was 29% and 69% greater than in standing and side-lying positions, respectively. The Ffemur based on supine TSTT (3380 [2017]N) was 19% lower than the standing position (4173 [1764]N) and 31% lower than the side-lying position (4908 [1524]N). As factor of risk was directly influenced by Ffemur, the relative effects on fracture risk were similar. While less pronounced (<10%), the effects of hip rotation angle were consistent across TSTT, Ffemur, and factor of risk. Based on the sensitivity of impact models to TSTT, these results highlight the need for a standardized TSTT measurement approach. In addition, the consistent influence of hip rotation on TSTT (and downstream model predictions) support its importance as a factor that may influence fall-related hip fracture risk.

Upright versus supine MRI: effects of body position on craniocervical CSF flow

BackgroundCerebrospinal fluid (CSF) circulation between the brain and spinal canal, as part of the glymphatic system, provides homeostatic support to brain functions and waste clearance. Recently, it has been observed that CSF flow is strongly driven by cardiovascular brain pulsation, and affected by body orientation. The advancement of MRI has allowed for non-invasive examination of the CSF hydrodynamic properties. However, very few studies have addressed their relationship with body position (e.g., upright versus supine). It is important to understand how CSF hydrodynamics are altered by body position change in a single cardiac phase and how cumulative long hours staying in either upright or supine position can affect craniocervical CSF flow.MethodsIn this study, we investigate the changes in CSF flow at the craniocervical region with flow-sensitive MRI when subjects are moved from upright to supine position. 30 healthy volunteers were imaged in upright and supine positions using an upright MRI. The cranio-caudal and caudo-cranial CSF flow, velocity and stroke volume were measured at the C2 spinal level over one cardiac cycle using phase contrast MRI. Statistical analysis was performed to identify differences in CSF flow properties between the two positions.ResultsCSF stroke volume per cardiac cycle, representing CSF volume oscillating in and out of the cranium, was ~ 57.6% greater in supine (p < 0.0001), due to a ~ 83.8% increase in caudo-cranial CSF peak velocity during diastole (p < 0.0001) and extended systolic phase duration when moving from upright (0.25 ± 0.05 s) to supine (0.34 ± 0.08 s; p < 0.0001). Extrapolation to a 24 h timeframe showed significantly larger total CSF volume exchanged at C2 with 10 h spent supine versus only 5 h (p < 0.0001).ConclusionsIn summary, body position has significant effects on CSF flow in and out of the cranium, with more CSF oscillating in supine compared to upright position. Such difference was driven by an increased caudo-cranial diastolic CSF velocity and an increased systolic phase duration when moving from upright to supine position. Extrapolation to a 24 h timeframe suggests that more time spent in supine position increases total amount of CSF exchange, which may play a beneficial role in waste clearance in the brain.

TOMOGRAFIA DE IMPEDÂNCIA ELÉTRICA NA POPULAÇÃO NEONATAL E PEDIÁTRICA: UMA REVISÃO SISTEMÁTICA

OBJECTIVE: Electrical impedance tomography (EIT) is a non-invasive and radiation-free monitoring technique. The evaluation of EIT results can guide the effectiveness of different therapies, enabling better decisions, standardized behavior, and optimization in the use of resources. The objective is to characterize the use of electrical impedance tomography in the neonatal and pediatric population. METHODS: This is a systematic review, in which articles without language restrictions that addressed the applicability of electrical impedance tomography in the neonatal and pediatric population were analyzed. This review followed the PRISMA recommendations (Key Items for Reporting Systematic Reviews and Meta-analysis). RESULTS: A total of 309 studies were found, of which 302 were excluded according to the eligibility criteria, and 7 were included. All studies investigated the applicability of EIT as an assessment tool for pediatric or neonatal patients. EIT was shown to be effective in evaluating ventilation before extubation, comparing transverse alterations and total lung volume, evaluating the effects of body and head positions on the spatial distribution of ventilation, for potential diagnostic use in pediatric patients with asthma, feasible as a complementary tool in the assessment of community-acquired pneumonia in children, monitoring ventilation and perfusion in newborns and critically ill children, and evaluating recent advances in EIT related to cardiopulmonary imaging. CONCLUSION: EIT has been shown to be an effective monitoring technique for pediatric and neonatal patients. Future studies are needed to improve clinical practice.

The Effect of Different Body Positions on Endotracheal Tube Cuff Pressure in Patients under Mechanical Ventilation.

Introduction: Maintaining endotracheal tube intracuff pressure (ETTICP) within an optimal range is crucial for effective ventilation and prevention of aspiration. This study aimed to determine the effect of changing body position on ETTICP in patients under mechanical ventilation.Methods: In the current single-group study, each patient was taken as his/her own control. Thirty patients who met the inclusion criteria were selected as the study sample. First, the patients were placed in a supine (flat) position, head of the bed was raised to 30 degrees, and ETTICP was set at 25 cmH2 O as the baseline. Then, the ETTICP changes in the three positions (left lateral, right lateral, and semi-fowler) were compared with the baseline. Interventions were made on a random basis among the patients. Data were analyzed by repeated-measures ANOVA using SPSS version 13.Results: There was a significant difference among ETTICP means in three different body positions, so that ETTICP was higher in the left lateral position compared to other positions. Moreover, there was a significant difference among ETTICP means 0, 15, 45, and 90 minutes after changing the body position. ETTICP means after 0 and 15 minutes were significantly higher than other times compared to the baseline.Conclusion: ETTICP changes were affected by different body positions and the passage of time. Thus, regular monitoring and adjusting of ETTICP after any body positioning is essential, especially immediately and 15 minutes after repositioning.

Simulating effect of neonate body position on carbon dioxide tension in oxygen tent

Oxygen therapy is a common method of respiratory support, but its use involves the risk of carbon dioxide recycling and the development of hypercapnia in the patient.The aim of the study. Assess the carbon dioxide tension in the oxygen tent depending on the patient's body position in the experimental newborn Model.Materials and Methods. The study was performed on the phantom of the newborn. Influence of 3 patient positions at fresh mixture feed rate 2.5, 5, 7 and 10 l/min is evaluated. Monitoring of the carbon dioxide tension was carried out using Testo 480, measurements were carried out for 60 minutes.Results of the study. A clear relationship was established between the position of the newborn's body and the tension of carbon dioxide in the oxygen tent. The minimum tension of carbon dioxide is noted in the patient's position ≪on the back≪ at a fresh mixture feed rate of 7.5 l/minute and is 527 ± 64 ppm, and the maximum ‒ in the child's position ≪on the stomach≪ at the same oxygen-air mixture feed rate: 1180 ± 63 ppm.Conclusion. The position of the newborn baby's body is the main factor affecting the carbon dioxide stress in the oxygen tent.

The effect of respiration and body position on terminal thoracic duct diameter and the lymphovenous junction: An exploratory ultrasound study.

The thoracic duct (TD) drains most of the body's lymph back to the venous system via its lymphovenous junction (LVJ), playing a pivotal role in fluid homeostasis, fat absorption and the systemic immune response. The respiratory cycle is thought to assist with lymph flow, but the precise mechanism underpinning terminal TD lymph flow into the central veins is not well understood. The aim of this study was to use ultrasonography (US) to explore the relationship between terminal TD lymph flow, the respiratory cycle, and gravity. The left supraclavicular fossa was scanned in healthy non-fasted volunteers using high-resolution (13-5 MHz) US to identify the terminal TD and the presence of a lymphovenous valve (LVV). The TD's internal diameter was measured in relation to respiration (inspiration vs. expiration) and body positioning (supine vs. Trendelenburg). The terminal TD was visualized in 20/33 (61%) healthy volunteers. An LVV was visualized in only 4/20 (20%) cases. The mean terminal TD diameter in the supine position was 1.7 mm (range 0.8-3.1 mm); this increased in full inspiration (mean 1.8 mm, range 0.9-3.2 mm, p< 0.05), and in the Trendelenburg position (mean 1.8 mm, range 1.2-3.1 mm, p< 0.05). The smallest mean terminal TD diameter occurred in full expiration (1.6 mm, range 0.7-3.1 mm, p< 0.05). Respiration and gravity impact the terminal TD diameter. Due to the challenges of visualizing the TD and LVJ, other techniques such as dynamic magnetic resonance imaging will be required to fully understand the factors governing TD lymph flow.

S360 Effects of Body Position on High-Resolution Manometry Data and Chicago Classification Diagnosis

S360 Effects of Body Position on High-Resolution Manometry Data and Chicago Classification Diagnosis

The Effect of Body Position and the Reliability of Upper Limb Arterial Occlusion Pressure Using a Handheld Doppler Ultrasound for Blood Flow Restriction Training.

The precise calculation of arterial occlusive pressure is essential to accurately prescribe individualized pressures during blood flow restriction training. Arterial occlusion pressure in the lower limb varies significantly between different body positions while similar reports for the upper limb are lacking. Body position has a significant effect in upper limb arterial occlusive pressure. Using cuffs with manual pump and a handheld Doppler ultrasound can be a reliable method to determine upper limb arterial blood flow restriction. A randomized repeated measures design. Level 3. Forty-two healthy participants (age mean ± SD = 28.1 ± 7.7 years) completed measurements in supine, seated, and standing position by 3 blinded raters. A cuff with a manual pump and a handheld acoustic ultrasound were used. The Wilcoxon signed-rank test with Bonferroni correction was used to analyze differences between body positions. A within-subject coefficient of variation and an intraclass correlation coefficient (ICC) test were used to calculate reproducibility and reliability, respectively. A significantly higher upper limb arterial occlusive pressure was found in seated compared with supine position (P < 0.031) and in supine compared with standing position (P < 0.031) in all raters. An ICC of 0.894 (95% CI = 0.824-0.939, P < 0.001) was found in supine, 0.973 (95% CI = 0.955-0.985, P < 0.001) in seated, and 0.984 (95% CI = 0.973-0.991, P < 0.001) in standing position. ICC for test-retest reliability was found 0.90 (95% CI = 0.814-0.946, P < 0.001), 0.873 (95% CI = 0.762-0.93, P < 0.001), and 0.858 (95% CI = 0.737-0.923, P < 0.001) in the supine, seated, and standing position, respectively. Upper limb arterial occlusive pressure was significantly dependent on body position. The method showed excellent interrater reliability and repeatability between different days. Prescription of individualized pressures during blood flow restriction training requires measurement of upper limb arterial occlusive pressure in the appropriate position. The use of occlusion cuffs with a manual pump and a handheld Doppler ultrasound showed excellent reliability; however, the increased measurement error compared with the differences in arterial occlusive pressure between certain positions should be carefully considered for the clinical application of the method. B.

Effects of Body Position and Hypovolemia on the Regional Distribution of Pulmonary Perfusion During One-Lung Ventilation in Endotoxemic Pigs

Background: The incidence of hypoxemia during one-lung ventilation (OLV) is as high as 10%. It is also partially determined by the distribution of perfusion. During thoracic surgery, different body positions are used, such as the supine, semilateral, lateral, and prone positions, with such positions potentially influencing the distribution of perfusion. Furthermore, hypovolemia can impair hypoxic vasoconstriction. However, the effects of body position and hypovolemia on the distribution of perfusion remain poorly defined. We hypothesized that, during OLV, the relative perfusion of the ventilated lung is higher in the lateral decubitus position and that hypovolemia impairs the redistribution of pulmonary blood flow.Methods: Sixteen juvenile pigs were anesthetized, mechanically ventilated, submitted to a right-sided thoracotomy, and randomly assigned to one of two groups: (1) intravascular normovolemia or (2) intravascular hypovolemia, as achieved by drawing ~25% of the estimated blood volume (n = 8/group). Furthermore, to mimic thoracic surgery inflammatory conditions, Escherichia coli lipopolysaccharide was continuously infused at 0.5 μg kg−1 h−1. Under left-sided OLV conditions, the animals were further randomized to one of the four sequences of supine, left semilateral, left lateral, and prone positioning. Measurements of pulmonary perfusion distribution with fluorescence-marked microspheres, ventilation distribution by electrical impedance tomography, and gas exchange were then performed during two-lung ventilation in a supine position and after 30 min in each position and intravascular volume status during OLV.Results: During one-lung ventilation, the relative perfusion of the ventilated lung was higher in the lateral than the supine position. The relative perfusion of the non-ventilated lung was lower in the lateral than the supine and prone positions and in semilateral compared with the prone position. During OLV, the highest arterial partial pressure of oxygen/inspiratory fraction of oxygen (PaO2/FIO2) was achieved in the lateral position as compared with all the other positions. The distribution of perfusion, ventilation, and oxygenation did not differ significantly between normovolemia and hypovolemia.Conclusions: During one-lung ventilation in endotoxemic pigs, the relative perfusion of the ventilated lung and oxygenation were higher in the lateral than in the supine position and not impaired by hypovolemia.