How did humans acquire erect bipedal walking?

There are a number of potential physical advantages to performing orotracheal intubation in an upright position. The objective of this study was to measure the success of intubation of a simulated patient in an upright versus supine position by novice intubators after brief training. This was a cross-over design study in which learners (medical students, physician assistant students, and paramedic students) intubated mannequins in both a supine (head of the bed at 0°) and upright (head of bed elevated at 45°) position. The primary outcome of interest was successful intubation of the trachea. Secondary outcomes included log time to intubation, Cormack-Lehane view obtained, Percent of Glottic Opening score, provider assessment of difficulty, and overall provider satisfaction with the position. There were a total of 126 participants: 34 medical students, 84 physician assistant students, and 8 paramedic students. Successful tracheal intubation was achieved in 114 supine attempts (90.5%) and 123 upright attempts (97.6%; P=0.283). Upright positioning was associated with significantly faster log time to intubation, higher likelihood of achieving Grade I Cormack-Lehane view, higher Percent of Glottic Opening score, lower perceived difficulty, and higher provider satisfaction. A subset of 74 participants had no previous intubation training or experience. For these providers, there was a non-significant trend toward improved intubation success with upright positioning vs supine positioning (98.6% vs. 87.8%, P=0.283). For all secondary outcomes in this group, upright positioning significantly outperformed supine positioning.

Helping the woman to adopt a comfortable position during childbirth significantly affects labor changes and pain management. However, there is a lack of consensus on the impacts of different childbirth positions on labor outcomes. In addition, a scarce of studies have assessed the effects of the upright and recumbent positions on delivery outcomes, especially in the Kingdom of Saudi Arabia. This study aimed to examine and compare the influence of upright and recumbent childbirth positions on birth outcomes. The setting was the childbirth unit at East Jeddah Hospital from November 2020 to March 2021. The research design was quasi-experimental, including 300 women in labor under 18-45 years. The sample includes two equal groups of 150 women: upright (experiment) and recumbent (comparison) position groups. Three tools were used to collect data: a structured interviewing questionnaire, the modified WHO partograph, and the Wong-Baker FACES® pain rating scale. Descriptive statistics, chi-square, independent t-test, and paired t-test were used for data analysis. Women in the recumbent position spent a longer duration in the first, second, and third stages of childbirth and had higher pain scores and less satisfaction with the assumed position than women in the upright position, with a highly significant difference (p <0.001). Laboring women in upright positions experienced faster progress of labor, shorter duration of childbirth, less pain, and higher satisfaction than those assumed recumbent positions. This study serves as an input for midwives and nurses to enable them to offer appropriate advice to improve intrapartum care. In addition, educational programs targeting pregnant women about the positive impacts of upright position on women's birth experience are encouraged.

Combined inhalation of nitric oxide and oxygen in patients with moderate to severe COPD: effect on blood gases

Background: Patients describe that body posture may affect their abdominal bloating, distension, and flatulence, but whether changes in position have objectively demonstrable effects, either beneficial or deleterious, has not been...

Our aim was to assess the efficacy and mechanism of solid bolus transit through the esophagus. Eight healthy volunteers were studied with concurrent manometry and videofluoroscopy while swallowing 5 ml liquid barium, a 5-6 mm diameter bread ball, and 4 g chewed bread in both a supine and upright posture. As many as four successive swallows were performed until clearance was achieved. The esophageal clearance of liquid barium was 100% with the first swallow. Clearance of the unchewed bread ball occurred with the first swallow in only 6.7% of trials in the upright posture and 5.9% in the supine posture. After four swallows, clearance was 100% and 52.9% in the upright and supine postures, respectively. Chewed bread was more readily cleared than unchewed bread, with 100% clearance after two swallows in the upright posture and 91% clearance after four swallows in the supine posture. The most common locus of bread stasis was at the aortic arch and carina. The bread boluses were noted to move more effectively when localized in the head as opposed to the tail of the bolus composite. Nonocclusive contractions often occurred at the bolus tail despite the increased peristaltic amplitude seen with the chewed bread. Failed peristalsis, a frequent cause for solid clearance failure, was observed during 30% of all bread swallows. This usually occurred distal to the stopping point of the bolus, suggesting it to be the result rather than the cause of impaired transit. Although infrequently perceived by these normal subjects and in contradistinction to liquid clearance, bread is rarely cleared from the esophagus with a single swallow. Mastication and an upright posture facilitate the esophageal transport of solids. Bolus composition and impaired bolus transit alter the amplitude and conductance of peristalsis. Manometric data pertaining to liquid clearance through the esophagus do not readily apply to bread.

Kinesthetic estimation of the main orientations from the upright and supine positions

Understanding the degree of facial mobility upon postural changes is of great clinical relevance especially if facial assessment, facial measurements and/or facial markings are done in an upright position, but facial procedures are performed in a supine position. The objective of this study is to investigate regional facial skin displacement and facial volume changes in individuals between upright and supine positions. This multi-center study analyzed a total of 175 study participants with a mean age of 35.0 (10.2) years and a mean body mass index of 24.71 (3.5) kg/m2. 3D surface scanning technology with automated registration and alignment was utilized, and multivariate analyses were performed with adjustment for age, gender, body mass index, facial skin sagging and laxity. The medial face displaced less than the lateral face in both cranial (0.88 mm) and in lateral (0.76 mm) directions, and the lower face displaced more than the middle face in both cranial (1.17 mm) and lateral directions (1.37 mm). Additionally, the medial face lost, on average, 3.00cc whereas the lateral face increased by 5.86cc in volume; the middle face increased by 2.95cc, whereas the lower face decreased by 0.98cc in volume. All p < 0.001. Practitioners should be mindful that there is a statistically significant change in facial soft tissues between the upright and supine positions and that the magnitude of the change does not necessarily reflect on the aging process alone but is a multi-factorial process which should be individualized for each patient's needs. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evidence-Based Answer There is no significant difference between upright and recumbent position during the second stage of labor on the incidence of third and fourth degree perineal lacerations, but the incidence of second-degree lacerations is increased in women delivering in upright positions (SOR: A, meta-analysis). Among women with an epidural, there is no difference between upright or recumbent position in the incidence of any perineal laceration requiring suturing (SOR: A, meta-analysis). Delivering with or without stirrups does not affect the incidence or severity of perineal lacerations (SOR: B, single RCT).

Introduction: Data about the influence of body position on hemodynamics is rare. Aims and Objective: To compare pulmonary hemodynamics at rest and exercise during right heart catheterization (exRHC) in supine and upright position. Methods: Retrospective analysis of adults undergoing exRHC due to suspected pulmonary hypertension (PH), with cohort A undergoing supine exRHC and cohort B supine and upright exRHC. We compared supine vs. upright resting hemodynamics within subjects of B overall and by subgroups. We compared supine vs. upright hemodynamics at rest and at exercise between precapillary PH cohort A & B. Results: 270 resp. 213 patients underwent exRHC in A/B (63/60% female, age 60±15/61±15 years, 52/31 no PH, 68/38 exercise PH, 126/120 pre-capillary PH, 24/24 post-capillary PH). The table shows supine and upright resting and exercise hemodynamics. Conclusion: Body position affects resting and exercise pulmonary hemodynamics. At rest in the overall population, all pressures and the cardiac index are lower in the upright versus supine position. Exercise hemodynamics in patients with precapillary PH revealed a similar maximal cardiac index, despite a higher workload and higher transpulmonary gradient (lower pulmonary arterial wedge pressure and higher mean pulmonary artery pressure) in the upright versus supine position and despite similar resting hemodynamics.

Simulation Study of Upright Prostate Radiation Therapy: Comparison of Upright and Supine Anatomy and Dose-Volumetric Factors.

Inasmuch as spinal taps in preterm infants are frequently accompanied by clinical deterioration, the optimal position for this procedure was investigated. Three positions were each randomly assigned for five minutes to 17 healthy preterm infants without a spinal tap actually being performed: (1) lateral recumbent with full flexion (flexed position), (2) lateral recumbent with partial neck extension (extended position), and (3) sitting with head support and spine flexion (upright position). Transcutaneous PO2 and PCO2 were monitored in all infants, minute ventilation (VI) in seven, and heart rate and blood pressure in ten infants. Mean transcutaneous PO2 decreased in each of the three positions. This decrease was significantly greater in the flexed (28 +/- 8 mm Hg) as compared with the extended (18 +/- 8 mm Hg, P less than .001) and upright (15 +/- 11 mm Hg, P less than .001) positions. Mean transcutaneous PCO2 increased only in the flexed position (3 +/- 4 mm Hg, P less than .005) and levels were still elevated five minutes after that position had been discontinued. The consistent decrease in transcutaneous PO2 was accompanied by a variable effect of positioning on VI and there were no episodes of airway obstruction or apnea greater than 10 seconds. Heart rate increased in each position whereas blood pressure remained unchanged. These data suggest that although hypoventilation may contribute to the observed decrease in transcutaneous PO2, ventilation/perfusion imbalance appears to be the major mechanism. As spinal taps performed in the widely accepted flexed position carry the greatest risk of potential morbidity, it is recommended that this position be modified with neck extension or that spinal taps be performed in the upright position.

The correlation between the anatomical cardiac and electrocardiographic axes has been discussed for several years. Using upright computed tomography, this study aimed to reveal the relationship between the anatomical cardiac and electrocardiographic axes in both the supine and upright positions. Upright CT and standard supine CT were performed for healthy volunteers, following electrocardiography in both upright and supine position. On CT images, the coordinates of apex, the center of aortic valve (AV) and mitral valve (MV) were recorded, and the vectors and angles were calculated. Subcutaneous and visceral fat volume were semi-automatically calculated in a workstation. From a total 190 volunteers, 41 males were performed electrocardiography and included for this study. The QRS and anatomical axes (AV-apex and MV-apex axis) were significantly correlated in both supine and upright positions, while the angle of the AV-apex to Z axis was the most correlated (supine: r = − 0.54, p = 0.0002, upright: r = − 0.47, p = 0.0020). The anatomical axis moved in the dorsal and caudal directions from the supine to upright position. Multiple regression analysis revealed that the anatomical axis from the AV-apex to the Z-axis was determined according to age, body height, subcutaneous and visceral fat volumes.

Understanding respiratory motions of liver and its surrogate organs is crucial for precise dose delivery in liver cancer radiotherapy. Although these motions have been studied for respiratory motion management in the supine posture, few studies have quantified them and evaluated their correlations in the upright posture. This study quantified the respiratory motions of liver and surrogate organs and evaluated the correlations between the liver motions and surrogate signals for respiratory motion monitoring in both the supine and upright postures. 4D dynamic volume computed tomography (CT) images were acquired from 13 asymptomatic volunteers in both supine and upright postures while free breathing. The 4D liver motions were calculated by performing deformable image registration. Subsequently, superior-inferior (SI) motion at the right diaphragm apex and anterior-posterior (AP) motion at the abdominal skin surface were obtained as surrogate signals from the 4D CT images. The average displacements and maximum magnitudes of liver motions and surrogate signals were compared between the postures. Moreover, the correlations between the liver motions and surrogate signals were evaluated based on correlation models. The average liver displacements from the end-exhalation along the SI, AP, and left-right directions were -6.1, 2.1, and -0.4 mm in the supine posture and -4.6, 2.5, and 0.1 mm in the upright posture, respectively. The maximum motion range along the SI direction significantly decreased from 16.3 ± 6.6 mm in the supine posture to 11.0 ± 2.7 mm in the upright posture. Similar to the supine posture, the correlation models also reproduced the liver motions with high fitting accuracy in the upright posture. Compared to the conventional supine posture, the liver SI motion became smaller in the upright posture while keeping evident correlations with the surrogate signals, which suggests the upright posture will allow precise dose delivery with reduced internal target margins.

This study was designed to evaluate the effects of domperidone, a peripheral dopaminergic antagonist, in diabetic patients with symptomatic orthostatic hypotension. Nine patients were admitted to the hospital, placed on a diet containing 150 mEq sodium, and studied for periods of 4 hours, on different days, in the following conditions: (1) supine position, (2) upright posture (UP), (3) UP after 10 mg domperidone, intravenously in bolus, and (4) UP after 3 days of domperidone, 30 mg orally. Before domperidone the mean blood pressure observed in supine position of 132 +/- 37/75 +/- 6 mm Hg fell to 75 +/- 22/57 +/- 13 mm Hg after 2 hours in UP. Acute domperidone did not change the blood pressure response to UP. After 3 days of oral domperidone and in UP for 2 hours, the mean blood pressure value of 89 +/- 21/61 +/- 8 mm Hg was higher than that before domperidone (p less than 0.05), with relief of symptoms in all patients. This blood pressure response to UP has been maintained in six patients who completed 6 months of therapy. No differences were observed in plasma renin activity, aldosterone, sodium, and potassium and in 4-hour urinary excretion of aldosterone, epinephrine, norepinephrine, and dopamine, determined during the UP tests. Administration of domperidone for 3 days reduced the falls in creatinine clearance and the urinary excretion of sodium and potassium induced by UP but did not alter the blood pressure and aldosterone dose-response curves to angiotensin II. Although the mechanism of action is not defined, it is concluded that domperidone is effective for the treatment of orthostatic hypotension in patients with diabetes.

Gastroesophageal reflux disease (GERD) is diagnosed by the reflux index of 24-hour pH monitoring (pH monitoring). In our previous study, GER episodes during the upright position were more frequent than those during the supine position in asthmatic children. In this study, we investigated the clinical usefulness of the mean hourly number of acid refluxes, designated as the mean number of acid refluxes/hour (h) during the upright position in addition to the pH index for the diagnosis of GERD. The subjects were 22 preschool asthmatic children. When the reflux index was over 4% or the mean number of acid refluxes/h during the upright position were three times more frequent than those during the supine position even if the reflux index was below 4%, we prescribed famotidine. Children whose asthmatic symptoms improved with famotidine were included in a GERD group. Children who did not meet the criteria by pH monitoring were included in a non-GERD group in asthmatic children. The GERD group was comprised of 9 children. In 2 out of 9 GERD group children, the reflux index was below 4%. The median of the mean number of acid refluxes/h during the upright position was 12.9 in the GERD group, and 3.15 in the non-GERD group. The mean number of acid refluxes/h during the upright position were associated with asthmatic symptoms (p < 0.05). Reflux during the upright position was associated with asthmatic symptoms. The mean number of acid refluxes/h during the upright position in addition to the reflux index could be useful in the diagnosis of GERD when associated with asthma.