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PubMedDate not supplied

A radiographic study of proximal radius anatomy with implications in radial head replacement.

Anteroposterior (AP) and lateral radiographs of 20 healthy volunteers' forearms were taken in three views (full supination, neutral rotation, and full pronation). Radial head maximum diameter and angular measurements between the axis of forearm rotation (AFR) and the radial neck axis (RNA) were made with digital calipers. Repeated-measures analysis of variance revealed a statistically significant difference between the three AP groups, with supination having the smallest values (P <.0001), but not for the lateral groups (P =.128). Comparison of the AFR-RNA angle between the AP supinated position and the three lateral views revealed a statistically significant difference among all of the pairs, with the AP supinated position having the smallest values. The RNA most closely approximated the AFR with the forearm in the supinated position. For best approximating the native AFR during radial head replacement, the cut should be made perpendicular to the neck axis with the elbow extended and the forearm in the supinated position.

Adult↗

PubMed2006

The impact of different positions and thoracial restrains on respiratory induced cardiac motion.

One of the limiting factors for high resolution magnetic resonance coronary angiography (MRCA) is the motion of the heart during breathing. Current approaches use mainly motion correction in one dimension. We aimed to determine the relation between diaphragmatic motion and cardiac motion as well as the potential influence from external restraints reducing thoracical anterior posterior (AP) motion. Four real time navigators were used to collect motion parameters, diaphragmatic cranio-caudal, cardiac cranio-caudal, diaphragmatic anterior-posterior, and thoracical anterior-posterior. Measurements were performed in prone and supine position and supine position with a thorax restraint. In supine, the highest correlation was found between cranio-caudal diaphragmatic and cardiac motion (r2 = 0.71, slope = 0.26; p < 0.05). Prone positioning or external restraints led to significant changes of motion patterns, with a lower correlation between diaphragmatic and cardiac position. External manipulation of breathing by prone positioning or thoracical restraints leads to a less accurate prediction of cardiac position from assessment of diaphragmatic positions compared to standard supine positioning.

Adult↗

PubMed2000

Aspiration in chest compression alone without mechanical ventilation in the head down position in dogs.

BACKGROUND: Previous work by the authors has shown that chest compressions alone without mechanical ventilation during cardiopulmonary resuscitation in the natural supine position was associated with pulmonary aspiration in dogs. The purpose of this investigation was to test the hypothesis that a head down position may prevent aspiration during chest compressions alone and whether oxygenation can be improved by simply insufflation of oral oxygen 10 min after cardiac arrest. METHODS: Cardiac arrest was induced in ten mongrel dogs which were anesthetized and paralysed. Eight underwent chest compressions alone in different head down positions using an automatic compressor at 9 kg compression force and 3 cm compression depth. The study was composed of two parts. Part 1 evaluated the effect of insufflation of 10 l/min O2, into the mouth of the dogs, 10 min after initiation of resuscitation, using chest compressions alone. Part 2 was designed to test our hypothesis that the head down position may protect the lungs from aspiration during chest compression alone. The mouths of the dogs were filled with mixed barium and the dogs underwent serial episodes of chest compressions, for 10 min each, in the 20 degree head down, 10 degree head down and the natural supine positions. Chest X-rays with antero-posterior and lateral views were taken to evaluate pulmonary aspiration. Two additional dogs underwent direct chest compression alone in the natural supine position and the time of chest compression was shortened to 5 min. RESULTS: All dogs in the natural position showed evidence of pulmonary aspiration of barium, five or six of the dogs showed tracheal aspiration in the 10 degree head down position, while no any barium was visualized in the tracheo-broncheal trees of the dogs in the 20 degree head down position. Supplemental oxygen in the mouth improved the mean PaO2 from 67 +/- 26 to 160 +/- 97 mmHg during chest compressions alone. CONCLUSION: Chest compression alone without mechanical ventilation in the supine position caused pulmonary aspiration in the unprotected airway in dogs. This complication could be prevented by adopting a 20 degree head down position. The 10 degree head down position seemed to reduce the severity of the pulmonary aspiration, but not enough to eliminate the danger altogether. Supplemental oxygen in the mouth can improve oxygenation in chest compressions alone.

Administration, Oral↗

PubMed1986

Decreased isometric knee flexion torque with hip extension in hemiparetic patients.

I measured the 90-degree isometric knee flexion torque of 12 hemiparetic patients while they performed unilateral knee flexion in sitting and supine positions. The measurements were taken to clarify why hemiparetic patients have difficulty flexing their involved knees when their involved hip is extended. The patients generated more torque in the sitting position than in the supine position and more torque on their nonparetic side than on their paretic side. The ratio of supine-to-sitting knee flexion torque did not differ significantly between sides. This finding suggests that hemiparetic patients do not have relatively greater difficulty generating knee flexion torque on their involved side with the hip extended than with the hip flexed. Recommendations for assessment and treatment are made with this finding in mind.

Adult↗

PubMed1994

Postural changes in pleural fluid constituents.

Measurement of pleural fluid constituents (pH, PCO2, protein, lactic dehydrogenase [LDH], glucose, red blood cells [RBC], and white blood cells [WBC]) are of value in the diagnosis of pleural effusions and in the separation of exudates from transudates. The position of the patient (sitting or lying) prior to thoracentesis may result in differences in the measurement of these constituents. We found significant postural changes (p < 0.05) in the measurement of pH, protein, LDH, and RBCs in all exudative effusions (n = 12) in the upright sitting position compared with the supine position. No postural changes were noted in the transudative effusions (n = 6). The location of basal pleural tumors and the molecular weight of certain constituents may explain this postural sedimentary effect. Repeated thoracentesis after 30 min in the sitting position may result in exudative values when borderline transudates are found in a patient previously in a supine position.

Aged↗

PubMed2005

Variation of 24-hour intraocular pressure in healthy individuals: right eye versus left eye.

PURPOSE: An assumption for the one-eye therapeutic trial of ocular hypotensive drugs is the symmetrical variation of intraocular pressure (IOP) between the two eyes. We evaluated whether or not 24-hour variations of IOP in the two eyes are similar in healthy individuals. DESIGN: Experimental study with human subjects. PARTICIPANTS: Ninety-one healthy individuals. METHODS: We reviewed bilateral IOP data collected from 38 younger (18-25 years) and 53 older (40-74 years) experimental subjects housed for 24 hours in a sleep laboratory. Intraocular pressure was measured every 2 hours using a pneumatonometer in the sitting and supine positions during the 16-hour diurnal/wake period and in the supine position during the 8-hour nocturnal/sleep period. Measurements were always taken first in the right eye. For each age group, the two eyes' means, peaks, troughs, and ranges of IOP during office hours, the diurnal period, the nocturnal period, and the 24-hour period were compared. The coefficient of determination was used to examine the strength of association between the right and left IOPs. MAIN OUTCOME MEASURES: Bilateral IOP. RESULTS: For each age group, the profiles of IOP variations were similar in the two eyes with either the habitual body positions (diurnal sitting and nocturnal supine) or the 24-hour supine position. Mean, peak, and trough IOPs in the right eye were slightly higher than those in the left eye during the defined periods. There was no difference in the IOP range, except for the supine IOP in the younger group during the diurnal period. Cosine fits of the 24-hour supine IOP indicate no difference in the estimated phase timing or the 24-hour variation between the two eyes. Coefficients of determination for single pairs of right and left IOPs were in the range of 0.311 to 0.741. CONCLUSION: Variations of 24-hour IOP in the right and left eyes are similar. However, because the strength of association between the two eyes is only moderate, it may be difficult to perform a one-eye therapeutic trial using single pairs of right and left eye IOP measurements.

Adolescent↗

PubMedDate not supplied

Diabetes mellitus and lung function.

OBJECTIVES: To assess the nature of pulmonary dysfunction in type 1 diabetes and the relationship of pulmonary function tests to diabetic factors and complication. SUBJECTS AND METHODS: Sixteen type 1 diabetic patients and 26 control subjects matched for age and sex were studied. We performed spirometry measurements and measured pulmonary diffusing capacity (DL(CO)) in sitting and supine position by the single-breath method corrected by alveolar volume (VA). Glycosylated hemoglobin (HbA(Ic)), retinopathy and microalbuminuria were included as parameters of metabolic control and diabetic complications. RESULTS: Diabetic patients showed a significant reduction of the following pulmonary function tests (% predicted value) as compared with control subjects: total lung capacity (TLC, 92.6 +/- 14.5 vs. 113.9 +/- 17.5, p < 0.001), lung diffusing capacity in sitting position (DL(CO), 90.4 +/- 21.1 vs. 107.7 +/- 15.6, p = 0.004), lung diffusing capacity in supine position (DL(CO), 88.3 +/- 19.3 vs. 111.9 +/- 19.9, p = 0.001). The differences in diffusing capacity corrected by alveolar volume in sitting and supine position (DL(CO)/VA) were not significant. By changing the posture from sitting to supine position both diabetic patients and control subjects significantly increased DL(CO)/VA (103.4 +/- 17.7 vs. 112.7 +/- 22.3, p = 0.046 and 99.5 +/- 13.4 vs. 114.4 +/- 13, p < 0.001, respectively). There was no correlation between pulmonary function tests and diabetic complications. CONCLUSION: These data indicate that type 1 diabetic patients showed reduced TLC and DL(CO), features of pulmonary restrictive dysfunction. There was no correlation between abnormal pulmonary function and the presence of other diabetic complications.

Adult↗

PubMed1993

Maternal positioning affects fetal heart rate changes after epidural analgesia for labour.

Adverse fetal heart rate (FHR) changes suggestive of fetal hypoxia are seen in patients with normal term pregnancies after initiation of epidural block for labour analgesia. It was our hypothesis that, in some parturients, these changes were a consequence of concealed aortocaval compression resulting in decreased uterine blood flow. We expected that the full lateral position compared with the wedged supine position would provide more effective prophylaxis against aortocaval compression. To test our hypothesis we studied the role of maternal positioning on FHR changes during onset of epidural analgesia for labour. Eighty-eight ASA Class I or II term parturients were randomized into two groups: those to be nursed in the wedged supine position and those to be nursed in the full lateral position during induction of an epidural block. External FHR monitoring was employed to assess the fetal response to initiation of labour epidural analgesia. Epidural catheters were sited with the parturients in the sitting position and the patients then assumed the study position. After a negative test dose, a standardized regimen of bupivacaine 0.25% was employed to provide labour analgesia. The quality and efficacy of the block were assessed using VAS pain scores, motor block scores and sensory levels. The results demonstrated that there was no difference in the quality of analgesia provided nor in the incidence of asymmetric blocks. There was no difference in the observed incidence of FHR changes occurring during the initiation of the epidural block.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesia, Epidural↗

PubMed2001

Homeokinesis and short-term variability of human airway caliber.

We hypothesized that short-term variation in airway caliber could be quantified by frequency distributions of respiratory impedance (Zrs) measured at high frequency. We measured Zrs at 6 Hz by forced oscillations during quiet breathing for 15 min in 10 seated asthmatic patients and 6 normal subjects in upright and supine positions before and after methacholine (MCh). We plotted frequency distributions of Zrs and calculated means, skewness, kurtosis, and significance of differences between normal and log-normal frequency distributions. The data were close to, but usually significantly different from, a log-normal frequency distribution. Mean lnZrs in upright and supine positions was significantly less in normal subjects than in asthmatic patients, but not after MCh and MCh in the supine position. The lnZrs SD (a measure of variation), in the upright position and after MCh was significantly less in normal subjects than in asthmatic patients, but not in normal subjects in the supine position and after MCh in the supine position. We conclude that 1) the configuration of the normal tracheobronchial tree is continuously changing and that this change is exaggerated in asthma, 2) in normal lungs, control of airway caliber is homeokinetic, maintaining variation within acceptable limits, 3) normal airway smooth muscle (ASM) when activated and unloaded closely mimics asthmatic ASM, 4) in asthma, generalized airway narrowing results primarily from ASM activation, whereas ASM unloading by increasing shortening velocity allows faster caliber fluctuations, 5) activation moves ASM farther from thermodynamic equilibrium, and 6) asthma may be a low-entropy disease exhibiting not only generalized airway narrowing but also an increased appearance of statistically unlikely airway configurations.

Adolescent↗

PubMed2002

Effect of postprandial posture on digestion and absorption of dietary carbohydrate.

The effect of postprandial body posture on digestion and absorption of dietary carbohydrate were examined through breath hydrogen test on 6 female subjects. During the experiment, the participants either sat on a chair or lay on their backs for the first 4 hr (from 08:00 to 12:00) after eating the test breakfast meal. They then remained sedentary on a sofa for 6 hr (12:00 to 18:00). Participants' end alveolar breath samples were collected for 10 hr (every 15 min from 08:00 to 12:30, and then every 30 min until 18:00). The experiment was conducted on two consecutive days using a randomized, crossover study design. The results demonstrated that in the supine position orocecal transit time of the test meal was significantly slower than in the sitting position (260 +/- 21 min and 238 +/- 20 min, respectively, p < 0.01). In addition, afternoon breath hydrogen excretion due to a partial malabsorption of dietary carbohydrate and its fermentation in the colon was significantly larger in the sitting position (144.0 +/- 24.1 ppm.hr) than in the supine position (110.0 +/- 26.1 ppm.hr, p < 0.05). These results support the hypothesis that there was a marked effect of postprandial body posture on the function of the digestive system. The present findings suggest that the postprandial supine position is preferable to the sitting position for the digestion and absorption of dietary carbohydrate.

Absorption↗

PubMed1998

Acute effects of continuous rotational therapy on ventilation-perfusion inequality in lung injury.

OBJECTIVE: To investigate ventilation-perfusion (VA/Q) relationships, during continuous axial rotation and in the supine position, in patients with acute lung injury (ALI) using the multiple inert gas elimination technique. DESIGN: Prospective investigation. SETTING: Eighteen-bed intensive care unit in a university hospital. PATIENTS AND INTERVENTIONS: Ten patients with ALI (PaO2/FIO2 ratio < 300 mm Hg) were mechanically ventilated in a pressure controlled mode and placed on a kinetic treatment table. MEASUREMENTS AND RESULTS: Distributions of VA/Q were determined 1) during rotation (after a period of 20 min) and 2) after a resting period of 20 min in the supine position. During axial rotation, intrapulmonary shunt (19.1 +/- 15% of cardiac output) was significantly reduced in comparison with when in the supine position (23 +/- 14%, p < 0.05), areas with "low" VA/Q were not affected by the positioning maneuver. General VA/Q mismatch (logarithmic distribution of pulmonary blood flow) was decreased during rotation (0.87 +/- 0.37) in comparison with when the patient was in the supine position (0.93 +/- 0.37, p < 0.05). Arterial oxygenation was significantly improved during continuous rotation (PaO2/FIO2 = 217 +/- 137 mm Hg) as compared with in the supine position (PaO2/FIO2 = 174 +/- 82 mm Hg, p < 0.05). The positive response of the continuous rotation on arterial oxygenation was only demonstrated in patients with a Murray Score of 2.5 or less, indicating a "mild to moderate" lung injury, while in patients presenting with progressive ARDS (Murray Score > 2.5), the acute positive response was limited. CONCLUSIONS: Continuous axial rotation might be a method for an acute reduction of VA/Q mismatch in patients with mild to moderate ALI, but this technique is not effective in late or progressive ARDS. Further studies including a large data collection are needed.

Adult↗

PubMed2001

Uvulopalatopharyngoplasty for obstructive sleep-related breathing disorders: one-year follow up.

The effectiveness of uvulopalatopharyngoplasty was evaluated in 28 patients (25 men and three women; mean age 47.6 years) with obstructive sleep apnea by comparing preoperative daytime polysomnography with those carried out 6 months and 1 year postoperatively. The mean apnea plus hypopnea index (AHI) in the supine position decreased from 51.0/h to 23.0/h 6 months postoperatively and 57.1% of patients showed a 50% or more reduction of AHI. By changing the sleep position from supine to lateral, 71.4% of the 28 patients indicated a 50% or more reduction in AHI before surgery, which increased to 92.3% of 26 patients 6 months postoperatively. The positive results of uvulopalatopharyngoplasty were maintained at least until 1 year after surgery.

Body Mass Index↗

PubMed2001

[A case of diaphragmatic paralysis in a patient with diabetes mellitus after surgery in prolonged prone position].

A 56-year-old woman with diabetes mellitus was scheduled for bilateral kidney lithotomy. She was in the prone position for about seven hours during operation. At the end of operation, arterial blood gas analysis showed PaO2 64 mmHg and PaCO2 44 mmHg under 100% oxygen inhalation through a face mask, and the chest x-rays showed elevation of the right diaphragm. Her trachea was intubated again. The right diaphragm returned to the preoperative level by positive pressure ventilation on supine position. Hypoxemia disappeared when the patient was placed in the sitting position, and the trachea was extubated. The right diaphragm returned to the normal level on the 1st postoperative day, but hypoxia continued until the 6th postoperative day with the patient on supine position. We speculate that the diaphragmatic paralysis was caused by over-extension of the neck for a prolonged period, and that the patient might have been susceptible to nerve injury due to underlying diabetes mellitus.

Diabetes Complications↗

PubMed1989

Measurement of normal portal venous blood flow by Doppler ultrasound.

The volume flow rate of blood in the portal vein was measured using a duplex ultrasound system. The many errors inherent in the duplex method were assessed with particular reference to the portal vein and appropriate correction factors were obtained by in vitro calibration. The effect of posture on flow was investigated by examining 45 healthy volunteers in three different positions; standing, supine and tilted head down at 20 degrees from the horizontal. The mean volume blood flow in the supine position was 864 (188)ml/min (mean 1SD). When standing, the mean volume blood flow was significantly reduced by 26% to 662 (169)ml/min. There was, however, no significant difference between flow when supine and when tilted head down at 20 degrees from the horizontal.

Adult↗

PubMed2006

[Expiratory flow limitation detected by negative expiratory pressure in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To evaluate the relationship between expiratory flow limitation (EFL) and chronic dyspnea and the effect of bronchodilator on EFL in patients with chronic obstructive pulmonary disease (COPD). METHODS: Thirty-three ambulatory patients with COPD (46 - 78 yrs; male 31, female 2) were included in this study. The severity of chronic dyspnea was rated according to the dyspnea scale proposed by the Medical Research Council (MRC). EFL was measured by applying negative pressure at the mouth during tidal expiration before and after bronchodilation test (inhalation of 400 microg salbutamol). RESULTS: EFL was detected in 12 (36%) of the 33 COPD patients in both seated and supine positions and in 11 (33%) only in supine position. There was a significant difference in the percent predicted forced expired volume in one second (FEV(1%)pred) between subgroups of the patients with or without EFL (t = 7.601, P < 0.01). The mean values of FEV(1%)pred in non-EFL group and EFL group was (66 +/- 16)% and (31 +/- 10)%, respectively, and the value was lowest in patients who showed EFL both in seated and supine positions [(24 +/- 7)%]. Both three-point EFL and five-point EFL were significantly correlated with FEV(1) (r = -0.836 and -0.818, respectively, all P < 0.01). There was a significant correlation between MRC dyspnea scale and three-point EFL and five-point EFL (r = 0.903 and 0.912, respectively, all P < 0.01). In the multiple regression analysis, five-point EFL was a better predictor of dyspnea than FEV(1) (regression coefficient was 0.679 and -0.265, respectively, P < 0.01 and 0.029, respectively). EFL persisted after salbutamol in all of the 23 patients with EFL under baseline conditions. CONCLUSIONS: EFL as measured by negative expiratory pressure (NEP) technique may be more useful in the evaluation of dyspnea in COPD patients than routine lung function measurements. The EFL in COPD patients is irreversible after bronchodilator administration.

Aged↗

PubMed1980

[Investigations concerning postural influences on blood and blood plasma (author's transl)].

Body position exerts considerable influence on transcapillary balance of protein-poor fluid, i.e., on the whole-body Starling equilibrium. Movement into upright position causes hemoconcentration whereas supine position makes hemodilution. This means that the alteration of blood and plasma volume influences, e.g., plasma protein concentration, hematocrit, and blood hemoglobin content. The application of the mechanical oscillator technique for high-precision density measurements on capillary blood and plasma, especially to quantify the time-course of alterations caused by posture, is discussed in this paper. Tilting into upright position (70 degrees) 45 min after recumbency led to an average increase of 6.6% after 10, and of 11.1% of plasma volume after 30 min in 12 test persons. In 13 test persons, tilting back into supine position (0 degrees) after 30-60 min of standing (70 degrees) caused a mean increase of plasma volume amounting 6.5% after 10, and of 10.5% after 30 min. Postural blood density variations showed shapes similar to that of plasma density, indicating blood volume alterations ranging between 5 and 10%. It is emphasized that, as a consequence for clinical practice, the body positioning before and during blood sampling must be taken into consideration especially in case of precise controls of the course of hematological variables, and in case of statistical comparisons among several test groups.

Adolescent↗

PubMed2006

Infant position in neonates receiving mechanical ventilation.

BACKGROUND: Several body positions other than standard supine position have been used in patients undergoing intensive care for reducing the incidence of pressure ulcers of the skin, contractures or ankylosis and for improving the patient's well being. In patients from different age groups undergoing mechanical ventilation (MV), it has been observed that particular positions, such as prone position, may improve some respiratory parameters. Benefits from these positions have not been clearly defined in critically ill newborns who may require mechanical ventilation for extended periods of time. OBJECTIVES: To assess the effects of different positioning of newborn infants receiving MV on short term respiratory outcomes and complications of prematurity. SEARCH STRATEGY: Databases searched (up to May 2006) were the Oxford Database of Perinatal Trials, CINAHL, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006). Hand searches of proceedings of the Society for Pediatric Research from 1990 to May 2006 were used to identify unpublished studies. SELECTION CRITERIA: Randomised or quasi randomised clinical trials comparing different positions in newborns receiving mechanical ventilation. DATA COLLECTION AND ANALYSIS: Three independent and unblinded reviewers assessed the trials for inclusion in the review and extracted the data. Data were double-checked and entered into the Review Manager software. MAIN RESULTS: Eleven trials involving 206 infants were included in this review. Several positions were compared: prone vs. supine, prone vs. lateral right, lateral right vs. supine, lateral left vs. supine, lateral right vs. lateral left and good lung dependent vs. good lung uppermost. Apart from one of the two studies that compared lateral right vs. lateral left positions, and one comparing prone vs. supine position, all the included studies had a crossover design. Comparing prone vs. supine position, an increase in arterial P02 in the prone position of between 2.75 and 9.72 mm Hg (95% CI) was observed (one trial). When % hemoglobin oxygen saturation was measured with pulse oximetry, improvement in the prone position was from 1.18 to 4.36% (typical effect based on four trials). In addition, there was a slight improvement in the number of episodes of desaturation. It was not possible to establish whether this effect remained once the intervention was stopped. Negative effects from the interventions were not described, although this issue was not studied in sufficient detail. Effects of position on other outcomes were not statistically significant; however, either positive nor negative effects cannot be excluded considering the small numbers that were studied. AUTHORS' CONCLUSIONS: The prone position was found to slightly improve the oxygenation in neonates undergoing mechanical ventilation. However, we found no evidence concerning whether particular body positions during mechanical ventilation of the neonate are effective in producing sustained and clinically relevant improvements.

Humans↗

PubMed2003

Relationship between postural change of the intraocular pressure and visual field loss in primary open-angle glaucoma.

PURPOSE: To determine the relationship between the postural changes of the intraocular pressure and the visual field loss in patients with primary open-angle glaucoma. METHODS: Eleven normal subjects and 11 patients with primary open-angle glaucoma were studied. Intraocular pressure was measured in both the sitting and the supine positions. Visual fields were measured with automated perimetry. RESULTS: When patients moved from a sitting to supine position, the intraocular pressure increased by an average of 3.1 +/- 0.4 mm Hg (mean +/- SEM) in normal subjects and 4.0 +/- 0.2 mm Hg in patients with primary open-angle glaucoma. There was a significant difference between the normal subjects and patients with primary open-angle glaucoma (P = 0.049). Intraocular pressure increased by 4.4 +/- 0.3 mm Hg (P = 0.02) in the worse eye for mean deviation and 3.6 +/- 0.3 mm Hg (P = 0.38) in the better eye for mean deviation. There was no significant difference in intraocular pressure in the sitting position between both groups. CONCLUSIONS: The greatest difference in intraocular pressure between the sitting and supine positions was observed in the worse eye of patients with primary open-angle glaucoma. This result suggests that damage to the optic nerve in primary open-angle glaucoma might occur when patients are asleep in the supine position.

Case-Control Studies↗