Effects of wrapped supine, unwrapped supine and prone positions on transcutaneous oxygen tension in neonatal pneumonia.
Explore the source record for details and available documents.
Blood Gas Monitoring, Transcutaneous↗
SEARCH · Search PubMed
Results for “Supination”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Effect of maternal postural change on maternal hemodynamics in late pregnancy--supine hypertension].
The purpose of this investigation was to ascertain the effect of postural change in late pregnant women from the left lateral recumbent position to the supine position on their blood circulation. Patients in whom the blood pressure at the right upper limb in the supine position increased by at least 20mmHg or more (diastolic and/or systolic pressure) were classified as the supine hypertensive group. Patients in whom the blood pressure of the right upper limb decreased by at least 20mmHg or more were classified as the supine hypotensive group. And other patients were classified as the no blood pressure change group. The results were as follows. 1. The incidence of supine hypertension was 48% in primigravidas and 38% in multigravidas. Supine hypertension was especially common in PIH (pregnancy induced hypertension) complicated women (75%). 2. Maternal cardiac function: With postural change from the left lateral recumbent position to the supine position, CO (cardiac output) decreased and SVR (systemic vascular resistance) was increased in both the supine hypertensive and the no blood pressure change groups by the thermodilution method (n = 14). CVP (central venous pressure) and PCWP (pulmonary capillary wedge pressure) shows different pattern of change in the supine hypertensive group and the no blood pressure change group. In the former group, CVP was decreased by 45 +/- 16% and PCWP was increased by 21 +/- 9% in the supine position compared with in the left lateral recumbent position. However, in the latter group, CVP decreased by 87 +/- 69% and PCWP decreased by 53 +/- 46% as the result of the same postural change.(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiac Output↗
Electromyography of pronators and supinators in great apes.
We obtained electromyographic recordings from the supinator, biceps brachii, pronator quadratus, and pronator teres muscles of a chimpanzee and a gorilla and from the supinator, pronator quadratus, and biceps brachii muscles of an orangutan as they stood and walked quadrupedally on horizontal and inclined surfaces, engaged in suspensory behavior, reached overhead, and manipulated a variety of foods and artifacts. In Pan troglodytes and Pan gorilla, as in Homo sapiens, the supinator muscle is the prime supinator, with the biceps brachii muscle serving to augment speed or force of supination. Primary of the pronator quadratus muscle over the pronator teres muscle during pronation is less clear in the African apes than in humans. Possibly, pongid radial curvature or forelimb elongation or both factors are related to the somewhat different patterns of activity that we observed in the pronator muscles of Pan versus those reported for Homo sapiens. In Pongo pygmaeus, as in P. troglodytes and P. gorilla, the pronator quadratus muscle acts as a pronator and the supinator muscle acts to supinate the hand at the radioulnar joints. The biceps brachii muscle is active at low levels as the orangutan supinates its hand with the elbow flexed.
Animals↗
Hemodynamic responses to seated and supine lower body negative pressure: comparison with +Gz acceleration.
Hemodynamic changes between upright and supine lower body negative pressure (LBNP) to levels of -70 mm Hg were compared in 8 subjects (5 males, 3 females) and correlated with their findings during simulated Shuttle reentry acceleration with a slow onset rate of 0.002 G/s (1,020 s to peak +2 Gz) and during gradual onset exposures (0.03 G/s) to +3 Gz and +4 Gz. Six of the 8 subjects were able to tolerate 2 min at peak +2 Gz, 2-5 min at +3 Gz, and 1-2 min at +4 Gz. Heart rate (HR) at any given level of upright LBNP regularly exceeded supine levels. HR change at -50 mm Hg in upright subjects (+47.7 bpm from 74.1 +/- 1.9 (M +/- S.E.) bpm, control) was 2.6 times greater than in supine subjects (+18.3 bpm from 64.8 +/- 2.8 bpm, control). HR values at -40 mm Hg supine (73.7 +/- 2.6) matched seated upright pre-LBNP control levels (74.1 +/- 1.9 bpm), while values at -70 mm Hg supine (102.5 +/- 4.4 bpm) were not significantly different from those at -40 mm Hg upright (103.1 +/- 4.0 bpm). Peak HR during +3 Gz (145.8 +/- 7.7 bpm) and +4 Gz (152.3 +/- 6.5 bpm) significantly exceeded recorded supine and upright LBNP levels, whereas values at +2 Gz (104.8 +/- 5.5 bpm) closely matched those at -40 mm Hg upright (103.1 +/- 4.0 bpm) and -70 mm Hg supine (102.5 +/- 4.4 bpm). Supine LBNP HR changes in this relatively small group of subjects closely matched those previously reported in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
The hemodynamic and metabolic basis for decreased aerobic capacity in the supine exercise compared with the upright exercise in coronary artery disease.
To elucidate the mechanism of reduced exercise tolerance in the supine position, 14 patients with coronary artery disease were studied by both supine ergometer exercise and upright treadmill exercise. Maximal oxygen consumption in the supine position amounted to 80% of that in the upright position (1110 +/- 453 vs 1387 +/- 470 ml/min; p less than 0.001). Maximal cardiac output was identical in both positions (12.07 +/- 4.44 vs 12.55 +/- 4.49 l/min; ns). Maximal arteriovenous oxygen difference in the supine position amounted to 83% of that in the upright position (9.22 +/- 1.92 vs 11.14 +/- 1.88 vol%; p less than 0.01). Thus, the lower maximal oxygen consumption in the supine position was not caused by the decreased cardiac output but by the impaired augmentation of arteriovenous oxygen difference. Lactate concentration at the same oxygen consumption was higher in the supine position, which means early augmentation of anaerobic metabolism. We concluded that the aerobic capacity in the supine position was significantly lower than that in the upright position in patients with coronary artery disease, and the impaired utilization of transported oxygen was considered to be one of the mechanisms of the decreased aerobic capacity in the supine position.
Adult↗
Maternal cerebral hemodynamics in the supine hypotensive syndrome.
Cerebral hemodynamics were studied in eight nonpregnant women and 24 women in late pregnancy by internal carotid artery velocimetry with a 3.5-MHz continuous-wave Doppler system. Criteria for supine hypotensive syndrome were a mean blood pressure decrease of 15 mmHg and a 2-minute sustained increase in pulse of 20 beats per minute under postural change from the left lateral to supine position. Nonpregnant and normal pregnant controls not meeting these two criteria displayed decreases of 22.9 and 21.7%, respectively, in time-averaged mean peak velocity (mean velocity) in the supine position compared with the left lateral position. Five subjects with subclinical supine hypotensive syndrome who met one of the above criteria showed a 37.0% decrease in internal carotid artery mean velocity in the supine position. Two patients with supine hypotensive syndrome could not tolerate the supine position for more than 6 minutes, at which time internal carotid artery mean velocity fell below 10 cm/second, reverse flow was observed, and they complained of dizziness, nausea, and syncope. Internal carotid artery mean velocity in all women showed no change in the sitting position compared with the left lateral position. These results indicate that the supine position should be avoided in late pregnancy, especially by women with cerebrovascular complications.
Adult↗
Supine position and sleep loss each reduce prolonged maximal voluntary ventilation.
Because of the prevalence of supine posture and sleep deprivation in both health and disease, we wondered how each of them influences prolonged maximal voluntary ventilation (MVV). Accordingly, we compared 12-second, 1-min, and 10-min isocapnic MVV supine with that measured in the upright posture in 8 healthy subjects. MVV decreased 6-10% supine, independent of test duration (p less than 0.01). Although end-expiratory lung volume was 0.47 liter lower during supine resting breathing (p less than 0.001), end-expiratory lung volumes during short-term MVV maneuvers were identical. To investigate any additional effect on MVV due to sleep loss, 12 healthy subjects performed 12-second, 1-min, and 30-min isocapnic MVV maneuvers in the supine position, either after normal sleep or after a 24-hour sleepless period. Sleep deprivation reduced MVV by 7-14%, again independent of test duration (p less than 0.05). Sleep loss also reduced the ventilation chosen to represent a submaximal (75%) breathing effect (p = 0.05), and it increased subjective ratings of fatigue and confusion (p less than 0.01). We conclude that supination and sleep deprivation together decrease both short- and long-term MVV by nearly 20%, with impairment of supination not caused by lung volume changes, and with the sleep loss effect occurring in tandem with a rise in the subjective assessment of breathing effort.
Adult↗
Gas exchange in dogs in the prone and supine positions.
To determine the cause of the difference in gas exchange between the prone and supine postures in dogs, gas exchange was assessed by the multiple inert gas elimination technique (MIGET) and distribution of pulmonary blood flow was determined using radioactively labeled microspheres in seven anesthetized paralyzed dogs. Each animal was studied in the prone and supine positions in random order while tidal volume and respiratory frequency were kept constant with mechanical ventilation. Mean arterial PO2 was significantly lower (P less than 0.01) in the supine [96 +/- 10 (SD) Torr] than in the prone (107 +/- 6 Torr) position, whereas arterial PCO2 was constant (38 Torr). The distribution of blood flow (Q) vs. ventilation-to-perfusion ratio obtained from MIGET was significantly wider (P less than 0.01) in the supine [ln SD(Q) = 0.75 +/- 0.26] than in the prone position [ln SD (Q) = 0.34 +/- 0.05]. Right-to-left pulmonary shunting was not significantly altered. The distribution of microspheres was more heterogeneous in the supine than in the prone position. The larger heterogeneity was due in part to dorsal-to-ventral gradients in Q in the supine position that were not present in the prone position (P less than 0.01). The decreased efficiency of oxygenation in the supine posture is caused by an increased ventilation-to-perfusion mismatch that accompanies an increase in the heterogeneity of Q distribution.
Animals↗
Cardiac size in the supine chestfilm.
The aim of this study was to find a normal value for the cardiac size in the supine position because such a standard is hardly known in the literature. Cardiac size in the erect and supine positions were compared in 165 patients in whom both chest radiographs were performed prior to kidney transplantation. For cardiac size as well as for cardiothoracic ratio (CTR) there is a linear relation between the measured values in the two positions which allows to determine the cardiac size in the supine position from a radiograph taken in the erect position and thus to determine whether cardiac enlargement exists in a supine chest film. A survey of 100 patients without cardiac or pulmonary pathology showed 16 patients with a heart size over 15 cm, the upper limit of normal as established over 20 years ago, which suggests that nowadays a new standard might be set. If so, the upper limit of normal CTR is 0.55 in the erect and 0.58 in the supine position. Two figures are presented to determine cardiac size and CTR in the supine position from the measured values in the erect position and vice versa.
Adolescent↗
[Aggravation of hypoxemia in supine position in myotonic dystrophy].
Myotonic dystrophy (MyD) involves a variety of systems. Respiratory disorders are common, namely elevation of diaphragm, alveolar hypoventilation, aspiration pneumonia and sleep apnea. We evaluated respiratory involvement. The subjects were 11 patients with MyD. Also 6 patients with limb girdle muscular dystrophy (LG) were examined to be compared with MyD. Both groups had the similar activities of daily living. All of them never complained of dyspnea. Arterial blood gas studies were performed in supine position and standing position. A new evidence was found that hypoxemia was aggravated and alveolar-arterial oxygen pressure difference was increased in supine position in MyD. Next, pulmonary function tests were done in supine position and sitting position. Functional residual capacity (FRC) were more reduced in supine position in MyD compared with LG. The value to subtract closing capacity from FRC was negative in supine position in MyD, showing closing phenomenon. We propose the mechanism of the aggravation of hypoxemia may be the following. The reduction of FRC caused by respiratory muscle involvement brings out the closing phenomenon. Abnormal uneven distribution of ventilation-perfusion ratio happens and then hypoxemia is worsened in supine position in MyD.
Adult↗
[Potentiating effect of a supine position on ischemia induced by exercise].
Though sitting bicycle and treadmill are the commonest devices used in exercise stress testing, supine ergometric test shows some advantages, especially in research investigations. The latter allows better ECG and blood pressure recordings during exercise. Recently, a greater frequency of ST-segment depression has been reported with supine vs upright exercise, but some doubt as to the ischemic significance of this result has been raised. Thus, we compare the ECG and hemodynamic pattern during upright and supine bicycle exercise in 50 subjects with chest pain, without prior myocardial infarction: 31 had documented coronary artery disease (CAD) and 19 had normal coronary vessels. In a subgroup (22 CAD patients and all subjects without CAD) a measurement of myocardial perfusion was performed during exercise using thallium-201 radionuclide ventriculography. Initial work-load and the further graded increases were identical for both postures. The frequency of ST-segment depression was higher during supine exercise (84% vs 74%). The increase in sensitivity (+7% vs CAD) was wider if a more direct measurement of myocardial ischemia was adopted as gold standard (+13% vs TI-201 responses) and was not associated with a decreased specificity (Tab. II). In the supine position the threshold of exercise-induced ST-segment depression was significantly lower. Chest pain appeared more frequently and at a lower work-load. Accentuation and precocity of exercise-induced ischemia in the supine-position could be attributed to an increased imbalance between supply and demand of MVO2 at equivalent work-load, heart rate changes, systolic blood pressure and double product were significantly higher.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Comparison of effects of upright versus supine body position and liquid versus solid bolus on esophageal pressures in normal humans.
New studies monitoring ambulatory esophageal pressures during food ingestion often compare results to normal values obtained from supine liquid swallows. We compared distal esophageal peristaltic and lower esophageal sphincter (LES) pressures in 15 normal subjects during six liquid swallows in the upright and supine positions, and six solid (small marshmallow) swallows in upright position. LES pressures were significantly (P less than 0.05) higher supine than upright but no differences were noted in LES pressure, relaxation, and duration of relaxation between upright solid and liquid swallows. Distal peristaltic wave velocities were faster upright than supine. Peristaltic wave amplitudes, durations, and DP/DT were significantly (P less than 0.05) greater in supine than in upright position. Atypical wave forms, defined as nontransmitted, simultaneous, and simultaneous/repetitive, increased in the upright position compared to supine (P less than 0.01), and during solid vs liquid swallows (P less than 0.05). These results indicate that body position substantially affects normal distal esophageal peristalsis and LES pressure and that "abnormal" wave forms occur more frequently during swallowing solids than liquids in the upright position. Conclusions regarding "abnormal" motility over prolonged periods and during food ingestion in patients should be tempered by these findings.
Adult↗
Regional variations in lung expansion in rabbits: prone vs. supine positions.
We studied the vertical gradient in lung expansion in rabbits in the prone and supine body positions. Postmortem, we used videomicroscopy to measure the size of surface alveoli through transparent parietal pleural windows at dependent and nondependent sites separated in height by 2-3 cm at functional residual capacity (FRC). We compared the alveolar size measured in situ with that measured in the isolated lungs at different deflationary transpulmonary pressures to obtain transpulmonary pressure (pleural surface pressure) in situ. The vertical gradient in transpulmonary pressure averaged 0.48 +/- 0.16 (SD) cmH2O/cm height (n = 10) in the supine position and 0.022 +/- 0.014 (SD) cmH2O/cm (n = 5) in the prone position. In mechanically ventilated rabbits, we used the rib capsule technique to measure pleural liquid pressure at different heights of the chest in prone and supine positions. At FRC, the vertical gradient in pleural liquid pressure averaged 0.63 cmH2O/cm in the supine position and 0.091 cmH2O/cm in the prone position. The vertical gradients in pleural liquid pressure were all less than the hydrostatic value (1 cmH2O/cm), which indicates that pleural liquid is not generally in hydrostatic equilibrium. Both pleural surface pressure and pleural liquid pressure measurements show a greater vertical gradient in the supine than in the prone position. This suggests a close relationship between pleural surface pressure and pleural liquid pressure. Previous results in the dog and pony showed relatively high vertical gradients in the supine position and relatively small gradients in the prone position. This behavior is similar to the present results in rabbits. Thus the vertical gradient is independent of animal size and might be related to chest shape and weight of heart and abdominal contents.
Animals↗
Effect of reaction time condition on EMG activities of the biceps brachii muscle in elbow flexion and forearm supination.
Under simple- and choice-RT conditions, the biceps brachii muscle was examined in 8 healthy male subjects to determine how the temporal and spatial characteristics of elbow flexion and forearm supination differed at the initial phase of EMG activity and whether preparation or the presence of response uncertainty influenced the EMG outputs of the two movements. In the simple-RT condition, RT of supination was significantly faster than that of flexion but EMG activity of supination was less than that of flexion. In contrast, in the choice-RT condition, RT of flexion was significantly faster than that of supination but EMG activity of flexion was significantly reduced compared to supination. These findings indicate that advanced preparation or motor set facilitates the differentiation of RTs and EMG activities of the response movements and that response uncertainty causes a significant change in the temporal and spatial specificity of both elbow flexion and forearm supination.
Adult↗
[Three-dimensional CT study of the carpus under pronation-supination constraints].
By studying 3D imaging of the wrist under pronation-supination strain, we found that the simple comparison of a series of two corresponding cuts may provide a great deal of useful information on how the carpus transmits the longitudinal torque from the forearm to the hand. A special wooden trestle was made to fix the subject in the CT scanner in a permanent effort of pronation or supination. In the first group of scans, this effort was said to be "free" because the hand was simply maintained in a fixed window without any muscular contraction, except pronation or supination muscles. In the second group of scans, this effort was said to be "constrained" because the hand gripped a fixed bar with contraction of the flexor muscles. The thickness of the cuts was 1.2 millimeters and they were separated by 1.5 millimeters. Four levels were specially studied: the lower radio-ulnar joint (LRUJ), the proximal row of the carpus, the distal one and the metacarpal bases. Many elementary movements occur in the carpus in constrained supination: the triquetrum "supinates" (7 degrees), the scaphoid flattens and "pronates" (2 degrees) around the capitum the ridges of the carpal anterior concavity approximate (3 mm). In constrained pronation, the anterior concavity of the carpus flattens emphasizing the role of the anterior retinaculum. The LRUJ is very unstable: in free pronation, the ulnar head moves dorsally, firmly pressing the posterior part of the sigmoid notch, responsible for fracture of a postero-medial fragment in Colles fracture. The quadratus pronatus is a very important muscle to coapt this joint. We propose the "screwing (or unscrewing) test" in the diagnosis of arthrosis or instability of the LRUJ. We define the notion of "rotational shift" to appreciate the quality of the pronation/supination torque transmission. In constrained pronation/supination, this rotational shift is 5 degrees in the radio-carpal joint. This is very important to appreciate the quality of the wrist prosthesis. In free pronation/supination, the rotational shift is 45 degrees between radius and metacarpal bases. In constrained pronation/supination, it becomes 10 degrees. The wrist ligaments are unable to resist the wrist rotational shift and favor the torque transmission. The tendinous caging of the wrist is the main factor for maintaining rigidity of the carpus and transmitting the torque as muscles are contracted. The wrist can be compared with a fluid drive clutch, whose pedal is muscular contraction.
Biomechanical Phenomena↗
[Value of supine thoracic radiography in the diagnosis and quantification of pleural effusions: comparison with sonography].
The purpose of this prospective study was to verify the value of the supine chest radiograph with regard to the recognition and quantification of pleural effusions. The findings of supine chest radiographs were compared to those of chest sonography in a total of 320 pleural cavities. The correct identification and quantification of a pleural effusion was possible by supine chest radiograph alone in only 55% of cases (176/320). In 20% (64/320) supine chest x-ray was falsely negative and in 15% (48/320) falsely positive. In 10% an existing effusion was in fact recognised on supine chest x-ray; however the amount of effusion was wrongly estimated.
Adolescent↗
Effect of lung inflation on regional lung expansion in supine and prone rabbits.
At functional residual capacity, lung expansion is more uniform in the prone position than in the supine position. We examined the effect of positive airway pressure (Paw) on this position-dependent difference in lung expansion. In supine and prone rabbits postmortem, we measured alveolar size through dependent and nondependent pleural windows via videomicroscopy at Paw of 0 (functional residual capacity), 7, and 15 cmH2O. After the chest was opened, alveolar size was measured in the isolated lung at several transpulmonary pressures (Ptp) on lung deflation. Alveolar mean linear intercept (Lm) was measured from the video images taken in situ. This was compared with those measured in the isolated lung to determine Ptp in situ. In the supine position, the vertical Ptp gradient increased from 0.52 cmH2O/cm at 0 cmH2O Paw to 0.90 cmH2O/cm at 15 cmH2O Paw, while the vertical gradient in Lm decreased from 2.17 to 0.80 microns/cm. In the prone position, the vertical Ptp gradient increased from 0.06 cmH2O/cm at 0 cmH2O Paw to 0.35 cmH2O/cm at 15 cmH2O Paw, but there was no change in the vertical Lm gradient. In anesthetized paralyzed rabbits in supine and prone positions, we measured pleural liquid pressure directly at 0, 7, and 15 cmH2O Paw with dependent and nondependent rib capsules. Vertical Ptp gradients measured with rib capsules were similar to those estimated from the alveolar size measurements. Lung inflation during mechanical ventilation may reduce the vertical nonuniformities in lung expansion observed in the supine position, thereby improving gas exchange and the distribution of ventilation.
Animals↗
Sacral curvature and supine posture.
Sacral curvature (SC), represented by the angle between the first and the last sacral vertebrae, is a feature that differentiates the human pelvis from that of other animals. The sacral curvature was measured and studied in 14 cebids, 31 cercopithecids, 17 hylobatids, 85 pongids, 23 normal human children, 15 children with orthopedic handicaps, 49 normal adult human males, and 64 normal adult human females. Sacral curvature was minimal to nil in monkeys (mean 11.5 +/- 6 SD degrees), and moderate in apes (hylobatids, mean 16 +/- 10 SD degrees; pongids, mean 27.2 +/- 16 SD degrees). In human newborns SC is minimal, increasing progressively until adolescence, reaching a mean of 64.7 +/- 29 SD degrees in adult humans. This study investigates the different factors contributing to the formation of the sacral curvature. These factors include 1) the effect of erect posture, which tilts the upper part of the sacrum dorsally and the lower part of the sacrum ventrally, and 2) the influence of supine posture, which affects the development of the lower part of the sacrum. In addition to supine posture the levator ani, which is well developed in Homo sapiens, also affects the lower part of the sacrum and coccyx and influences its ventral orientation. Variation in SC can result from differences in onset and frequency of supine posture. This is the first time that supine posture has been shown to play a role in shaping the human pelvis, although it is as characteristic of H. sapiens as is erect posture.
Adolescent↗