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Results for “Supine Position”

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PubMed1998

Positional changes and stabilization of middle ear pressure.

Middle ear pressure has been shown to increase when body position is shifted from the erect to the supine position, which is explained by an increased volume of the middle ear mucosa due to an increased hydrostatic pressure. The increase in the volume of middle ear mucosa consists of a fast major response followed by slow minor increase, which is reflected by a similar pattern in the increase of middle ear pressure. Since many otological experiments may be performed with subjects in the supine position, it is of interest to analyse these changes in middle ear pressure, as results may be affected by changes in middle ear pressure. The present study investigated the middle ear pressure changes due to a shift in body position from sitting to supine at time intervals of 15 s over a period of 120 s in a group of 20 normal adults. The middle ear pressure was found to increase 22 daPa (mean; S.D. = 12.1), whereas a stable middle ear pressure was reached after 30 s, indicating a steady state concerning the increase in volume of the middle ear mucosa. Thus, it is recommended that experiments with subjects in the supine position should be carried out only after assuming the position for 30 s. The increase in pressure did not correlate to the prevailing middle ear pressure or to the body height.

Acoustic Impedance Tests↗

PubMed2001

Expiratory flow limitation and orthopnea in massively obese subjects.

BACKGROUND: Morbidly obese subjects, who often complain about breathlessness when lying down, breathe at low lung volume with a reduced expiratory reserve volume (ERV). Therefore, during tidal breathing the expiratory flow reserve is decreased, promoting expiratory flow limitation (EFL), which is more likely to occur in the supine position, when the relaxation volume of the respiratory system, and hence the functional residual capacity (FRC), decrease because of the gravitational effect of the abdominal contents. PURPOSE: The aim of the study was to assess EFL and orthopnea in massively obese subjects and to evaluate whether orthopnea was associated with the development of supine EFL. METHODS: In 46 healthy obese subjects (18 men) with a mean (+/- SD) age of 44 +/- 11 years and a mean body mass index (BMI) of 51 +/- 9 kg/m(2), we assessed EFL in both the seated and the supine positions by the negative expiratory pressure method and assessed postural changes in FRC by measuring the variations in the inspiratory capacity (IC) with recumbency. Simultaneously, dyspnea was evaluated in either position using the Borg scale dyspnea index (BSDI) to determine the presence of orthopnea, which was defined as any increase of the BSDI in the supine position. RESULTS: Partial EFL was detected in 22% and 59%, respectively, of the overall population in seated and supine position. The mean increase in the supine IC amounted to 120 +/- 200 mL (4.1 +/- 6.4%), indicating a limited decrease in FRC with recumbency in these subjects. Orthopnea, although mild (mean BSDI, 1.7 +/- 1.3), was claimed by 20 subjects, and in 15 of them EFL occurred or worsened in the supine position. Orthopnea was associated with lower values of seated ERV (p < 0.05) and was marginally related to supine EFL values (p = 0.07). No significant effect of age, BMI, obstructive sleep apnea-hypopnea syndrome, FEV(1), and forced expiratory flow at 75% of vital capacity was found on either orthopnea or EFL. CONCLUSION: In morbidly obese subjects, EFL and dyspnea frequently occur with the subject in the supine position, and both supine EFL and low-seated ERV values are related to orthopnea, suggesting that dynamic pulmonary hyperinflation and intrinsic positive end-expiratory pressure may be partly responsible for orthopnea in massively obese subjects.

Adult↗

PubMed1992

[Dimensions of the pharynx in function of the posture, in neonates and infants].

The authors measured the pharyngeal patency of 25 wakeful newborns and infants on X-ray films of the lateral upper airway. The upper airway patency depends on the head position. The velopharyngeal and the posterior tongue space are smaller in supine position than in ventral position. In supine position the airway space behind the base of the tongue is significantly greater when the head is extended than when the head is in neutral position (p less than 0.007).

Head↗

PubMed1998

Expiratory flow limitation and intrinsic positive end-expiratory pressure in obesity.

Breathing at very low lung volumes might be affected by decreased expiratory airflow and air trapping. Our purpose was to detect expiratory flow limitation (EFL) and, as a consequence, intrinsic positive end-expiratory pressure (PEEPi) in grossly obese subjects (OS). Eight OS with a mean body mass index (BMI) of 44 +/- 5 kg/m2 and six age-matched normal-weight control subjects (CS) were studied in different body positions. Negative expiratory pressure (NEP) was used to determine EFL. In contrast to CS, EFL was found in two of eight OS in the upright position and in seven of eight OS in the supine position. Dynamic PEEPi and mean transdiaphragmatic pressure (mean Pdi) were measured in all six CS and in six of eight OS. In OS, PEEPi increased from 0.14 +/- 0.06 (SD) kPa in the upright position to 0.41 +/- 0.11 kPa in the supine position (P < 0.05) and decreased to 0.20 +/- 0.08 kPa in the right lateral position (P < 0.05, compared with supine), whereas, in CS, PEEPi was significantly smaller (<0.05 kPa) in each position. In OS, mean Pdi in each position was significantly larger compared with CS. Mean Pdi increased from 1.02 +/- 0.32 kPa in the upright position to 1.26 +/- 0.17 kPa in the supine position (not significant) and decreased to 1. 06 +/- 0.26 kPa in the right lateral position (P < 0.05, compared with supine), whereas there were no significant changes in CS. We conclude that in OS 1) tidal breathing can be affected by EFL and PEEPi; 2) EFL and PEEPi are promoted by the supine posture; and 3) the increased diaphragmatic load in the supine position is, in part, related to PEEPi.

Adult↗

PubMed2004

Normal and transplanted lateral knee menisci: evaluation of extrusion using magnetic resonance imaging and ultrasound.

The aim of the study is to develop a clinically useful and reproducible method for evaluating lateral meniscal extrusion in normal and transplanted knees under different axial loading conditions. Magnetic resonance imaging (MRI) and ultrasound (US) were used to assess meniscal extrusion. Both types of imaging were performed at least 6 months postoperatively (mean 23.5 months). Coronal MR images (DESS-3D sequence) of the lateral compartments of 10 normal knees and 17 transplanted lateral knees were analyzed. Extrusion was defined as the distance measured from the femoral condyle or tibial plateau to the outer edge of the meniscus. Subjects were examined in the supine position. Ultrasound print-outs of the lateral compartment of both knees of ten patients (transplanted side and contralateral normal side) were analyzed. Extrusion cross-sectional area (CSA) and distance were measured just anterior to the lateral collateral ligament: the former was defined as the CSA of the meniscus outside the knee, the latter as the greatest distance from a line connecting the femur and tibia to the outer edge of the lateral meniscus. Patients were examined in the supine position, bipodal stance and unipodal stance. The viable meniscal allograft was securely sutured to a bleeding functional meniscal rim. No bone blocks were used to fix the allograft; instead, the anterior and posterior horn were firmly sutured to their enthesis. The MRI results (tibial) show the transplanted lateral meniscus to be significantly (p<0.005) more extruded in comparison to the normal lateral meniscus. The anterior horn (mean 5.8 mm, SD=2.8) of the transplanted lateral meniscus tends to be more extruded than the posterior horn (mean 2.7 mm, SD=1.48). The posterior horn of the normal lateral meniscus does not (mean 0 mm) extrude, while the mean extrusion of the anterior horn is 0.8 mm (SD=0.92). In the US results, the transplanted lateral meniscus is significantly (p<0.005) more extruded than the normal lateral meniscus in all patient positions. Both cross-sectional surface and distance are equally good parameters to determine meniscal extrusion. There is no statistical difference between patient positions. The transplanted lateral meniscus extrudes, in the supine position, bipodal and unipodal stance 6.43 (SD=1.84), 6.01 (SD=1.93) and 6.99 mm (SD=2.7) respectively. The extrusion surface of the lateral transplanted meniscus is 50.50 mm2 (SD=15.32), 47.24 mm2 (SD=14.35) and 58.61 mm2 (SD=29.65) in the supine position, bipodal stance and unipodal stance respectively. The normal lateral meniscus extrudes in the supine position, bipodal and unipodal stance 3.77 (SD=1.76), 3.94 (SD=1.66) and 3.79 mm (SD=1.79) respectively. The extrusion surface of the normal lateral meniscus is 22.42 mm2 (SD=12.54), 23.24 mm2 (SD=12.74) and 24.79 mm2 (SD=10.18) in the supine position, bipodal stance and unipodal stance respectively. The presented data shows that the transplanted lateral meniscus, without bone block fixation but with firm fixation of the horns to the original entheses, extrudes in the lateral direction significantly more than the normal meniscus. The transplanted lateral meniscus, however, does not extrude more in the lateral direction under axial load. The anterior horn of both normal and transplanted menisci is extruded more laterally than the posterior horn. Both methods are adequate to measure laterally-directed extrusion of the normal and transplanted lateral meniscus, but have distinctive advantages and disadvantages: MRI in this series visualizes the complete-from posterior to anterior-meniscal body, but only in the supine, non-weight-bearing position. Using ultrasound one can evaluate the meniscal extrusion in different conditions of axial loading, but only from a single examination point.

Adolescent↗

PubMed1995

Effects of ascites and body position on gas exchange in patients with cirrhosis.

The effects of ascites and body position on gas exchange were evaluated in 22 male cirrhotics. All underwent spirometry and plethysmography in the sitting (erect) position. Single breath carbon monoxide diffusing capacity (DLco) was measured in the erect and supine positions in a random sequence. A significantly negative correlation was found between Kco (DLco corrected by alveolar volume [VA]) and lung volumes. DLco was significantly higher in the erect than in the supine position. On the other hand, Kco was significantly higher in the supine position. The differences of DLco and Kco between the erect and supine positions (the data in the supine minus those in the erect position) correlated highly with FEV1 and FVC. Thirteen patients underwent large volume paracentesis, and pulmonary function tests were done one day before and after paracentesis. Lung volumes and DLco increased significantly after paracentesis. In contrast, Kco decreased significantly. A significantly negative correlation was found between the change of Kco before and after paracentesis and that of lung volumes (the data after minus those before paracentesis). There was no remarkable change in the differences of DLco and Kco between the two positions after paracentesis. It is concluded that ascites may prevent further worsening of gas exchange and attenuate the postural effect on gas exchange in cirrhotic patients with significant amounts of ascites.

Adult↗

PubMed1996

Provocation of left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. Comparison of orthostasis testing and nitrate application.

Several provocation maneuvers are described in hypertrophic cardiomyopathy to Doppler echocardiographically distinguish the obstructive from the non obstructive type. No data are available about the value of orthostasis testing in comparison with nitrate application in this disease. In this study, 16 consecutive patients with hypertrophic cardiomyopathy were examined. 11 patients with hypertrophic cardiomyopathy were classified as obstructive, 5 patients with hypertrophic cardiomyopathy as non obstructive. Normal left ventricular outflow tract velocities as detected by the Doppler method were defined as < 2.0 m/s. Doppler echocardiographic measurements were performed after 10 minutes in supine position, within 10 minutes after head-up tilt and again, within 10 minutes in supine position. If systolic blood pressure during this examination exceeded 100 mm Hg 2.5 mg isosorbiddinitrate were sprayed sublingually. Measurements were done after 20 minutes in supine position and within 10 minutes after head-up tilt. Only in 7 of the 11 patients with hypertrophic obstructive cardiomyopathy maximal left ventricular outflow tract velocity in supine position measured > 2.0 m/s (2.2 +/- 0.8). During head-up tilt, all patients showed increased values (3.8 +/- 1.2 m/s). No differences in maximal left ventricular outflow tract velocity between head-up tilt and nitrate application in supine position (3.5 +/- 1.4 m/s) were present. All patients with hypertrophic non obstructive cardiomyopathy showed maximal left ventricular outflow tract velocities < 2.0 m/s in every step of the examination. Consequently, orthostasis testing was able to identify all patients with hypertrophic obstructive cardiomyopathy and demonstrated a diagnostic value similar to nitrate application.

Adult↗

PubMed2003

Respiratory inductance plethysmography in healthy 3- to 5-year-old children.

STUDY OBJECTIVES: Because of the challenges of using standard measurements such as spirometry to measure respiratory function in 3- to 5-year-old children, there may be a role for respiratory inductive plethysmography (RIP), which is noninvasive and requires minimal subject cooperation. In this study, we described normative values of thoracoabdominal motion and timing mechanics in 3- to 5-year-old children, and hypothesized positional dependence of these measurements in this age group. DESIGN: We measured relative thoracoabdominal motion during tidal breathing using the phase angle (Phi), the labored breathing index, and the phase relation during the total breath and timing mechanics with the ratio of time to peak tidal expiratory flow to expiratory time (TPTEF/TE). SETTING: Preschools within the greater Philadelphia area and the Pulmonary Office of The Children's Hospital of Philadelphia. PATIENTS OR PARTICIPANTS: Fifty healthy children between 3 years and 5 years of age. INTERVENTIONS: RIP. MEASUREMENTS AND RESULTS: All measures varied with position. Thoracoabdominal motion was nearly synchronous in the sitting position and most asynchronous in the supine position (Phi, 15.7 +/- 4.0 degrees vs 56.1 +/- 4.3 degrees, respectively; p < 0.001). This also led to an increase in the TPTEF/TE from the sitting to the supine positions (30.3 +/- 1.4% vs 37.0 +/- 1.6%, respectively; p < 0.001). Measurements of thoracoabdominal motion and timing mechanics did not change with age, weight, height, or gender. CONCLUSIONS: We conclude that the positional dependence of these measurements is due to the alteration in respiratory mechanics between the sitting, standing, and supine positions. We further conclude that if RIP is to be a useful longitudinal measure of respiratory function in this age range, comparison measurements should be made in the same position.

Abdominal Wall↗

PubMedDate not supplied

Usefulness of electron beam tomography in the prone position for detecting atrial thrombi in chronic atrial fibrillation.

OBJECTIVE: We compared the usefulness of electron beam tomography (EBT) in the prone position relative to that in the supine position for detecting atrial thrombi. METHODS: We studied 96 patients with chronic atrial fibrillation, of whom 71 were scanned in the supine position and 25 were scanned in the prone position. Electron beam tomography was performed twice after contrast medium injection to obtain early- and late-phase images. RESULTS: Filling defects were detected in 13 patients in the supine position by EBT. Transesophageal echocardiography (TEE) revealed a thrombus in the region of the filling defect in 9 patients. In 4 patients, filling defects in the left atrial appendage were not confirmed as thrombi by TEE. Filling defects were detected in 4 patients in the prone position, all of which were confirmed as thrombi by TEE. CONCLUSION: Electron beam tomography in the prone position is an effective technique for reducing false-positive results in the detection of atrial thrombi.

Aged↗

PubMed2000

Optimization of CT colonography technique: prospective trial in 180 patients.

PURPOSE: To assess the added benefits of prone positioning in addition to supine positioning and oral iodinated contrast medium for help in the detection of colonic polyps at computed tomographic (CT) colonography. MATERIALS AND METHODS: CT colonography was performed in prone and supine positions in 180 patients with polyps or risk factors for colonic neoplasia. Patients were randomly assigned to receive a standard bowel preparation or a standard preparation plus oral iodinated contrast medium. One radiologist interpreted supine images alone, and another analyzed supine and prone images. All patients subsequently underwent colonoscopy. RESULTS: At colonoscopy, 121 large (> or =1-cm-diameter) polyps and 142 smaller (0.5-0.9-cm) polyps were identified. Prone positioning resulted in increased sensitivity for identification of patients with large (> or =1-cm) polyps (increase from 70% to 85%, P: =.004) and of patients with polyps 0.5 cm or larger (increase from 75% to 88%, P: <.005), with no change in specificity. Use of oral contrast medium did not significantly improve polyp detection even in the subset of patients in whom colonic fluid attenuation was markedly increased. CONCLUSION: Acquisition and review of supine and prone CT colonographic images significantly improves the ability to identify patients with polyps 0.5 cm in diameter or larger. Administration of oral iodinated contrast medium does not significantly improve polyp detection.

Colon↗

PubMed2005

Influence of supine sleep positioning on early motor milestone acquisition.

This study aimed to determine whether supine sleep-positioned infants have delayed motor skills at age 4 and 6 months, and if delays are associated with decreased exposure to prone position. One 4 and one 6-month-old sample of healthy infants born at term were recruited. Motor assessments included the Peabody Developmental Motor Scale (PDMS) and Alberta Infant Motor Scale (AIMS). Parents completed an infant behavior diary for 3 consecutive days. Seventy-one 4-month-old infants were assessed (38 males; mean age 4.4 mo, standard deviation [SD] 0.2). Mean motor scores were close to normative standards (AIMS 47.7, SD 19.6; PDMS gross motor quotient [GMQ] 96.3, SD 6.5; PDMS fine motor quotient [FMQ] 99.2, SD 4.8). No infant scored below cut-off values used to identify motor delay. Milestones less likely to be achieved included extended arm support in prone, hands to feet in supine, and sitting with arm support. Exposure to 'tummy time' while awake was correlated with AIMS scores (r = 0.38, p < 0.01). F i fty 6-month-old infants were assessed (21 males; mean age 6.4 mo, SD 0.4). Mean scores were shifted down for all scales, and as much as 1 SD for PDMS (AIMS 44.5, SD 21.6; PDMS GMQ 85.7, SD 7.6; PDMS FMQ 88.9, SD 9.0). Only 22% of 6-month-olds could sit without arm support versus 50% expected in a normative sample. Remarkably, 22% of our sample exhibited gross motor delays (quotient <78). Tummy time (awake) was significantly associated with the AIMS (r = 0.64) and PDMS GMQ (r = 0.55) and FMQ (r = 0.33) quotients, even after adjusting for confounders. Typically developing infants who were sleep-positioned in supine had delayed motor development by age 6 months, and this was significantly associated with limited exposure to awake prone positioning. This has important implications for interpreting motor assessments of infants at risk and for preventing inappropriate referrals.

Age Factors↗

PubMed2005

Maximal urethral closure pressure < 20 cm H2O: does it predict intrinsic sphincteric deficiency?

OBJECTIVE: To assess whether the large discrepancy in the literature in the incidence of intrinsic sphincteric deficiency (ISD) is due to different methods by which maximal urethral closure pressure (MUCP) is measured. STUDY DESIGN: We compared the measurement of MUCP in the supine position with 300 mL saline in the bladder, according to International Continence Society guidelines, to that in the sitting position (full bladder) in 54 consecutive patients who were diagnosed as having stress urinary incontinence. RESULTS: In the supine position the mean MUCP was 38.4 +/- 2.85 cm H2O as compared to 22.80 +/- 3.22 cm H2O in the sitting position (p < 0.0001). The mean difference was 15.65 +/- 2.11 cm H2O. MUCP < or = 20 cm H2O was observed in 14 of 54 (25.9%) patients in the sitting position as compared to 1 of 54 (1.8%) in the supine position. CONCLUSION: When MUCP is measured in the supine position, according to International Continence Society guidelines, the cutoff point for diagnosis of ISD should be 35 rather than 20 cm H2O.

Adult↗

PubMed2004

Clinical predictors in obstructive sleep apnea patients with computer-assisted quantitative videoendoscopic upper airway analysis.

AIM: To identify the clinical predictors and assist surgeons in their clinical management of obstructive sleep apnea (OSA). A prospective study with a new approach to analyze the static and dynamic upper airway morphology between patients with OSA and normal subjects. METHOD: Quantitative computer-assisted videoendoscopy (validated with upper airway magnetic resonance imaging) was performed in 49 (43 males, 6 females) patients with OSA and compared with 39 (22 males, 17 females) controls (apnea-hypopnea index [AHI] < 5). Absolute cross-sectional areas and transverse and longitudinal diameters at the retropalatal and retrolingual levels were measured during end of quiet respiration and during Mueller's maneuver in the erect and supine positions, allowing us to study static and dynamic morphology (collapsibility) of the upper airway. Three thousand seven hundred forty-four (3,744) parameters were analyzed. RESULTS: In males, retropalatal and retrolingual areas during Mueller's maneuver in the supine position of 0.7981 cm (relative operating characteristics [ROC] = 0.9284, positive pressure ventilation [PPV] = 86.05%, negative pressure ventilation [NPV] = 84.62%) and 2.0648 cm (ROC = 0.8183, PPV = 76%, NPV = 83.33%), respectively, were found to be good predictors/cut-off values for OSA. The retropalatal area measured in the supine position (AS1 mol/L) and collapsibility of the retropalatal area in the supine position (CAS1) were found to have significant correlations with severity of OSA. In females, the areas measured during Mueller's maneuver in the supine position of 0.522 cm at the retropalatal level (ROC = 1, 100% PPV and NPV) and the transverse diameter at the retrolingual level during erect Mueller's maneuver of 1.1843 cm (ROC = 0.9056, PPV = 100%, NPV = 83.33%) were found to be predictive. All measurements at the retropalatal level and in the supine position had higher predictability. Area measurements obtained during Muller's maneuver were more predictive (ROC > 0.9910) than resting measurements (ROC >0.8371). Several sex and anatomic-site specific formulas with excellent predictability (ROC close or equal to 1) were also devised. CONCLUSION: Upper airway Mueller's studies are predictive and useful (independent samples t test/Mann-Whitney U test, ROC) in identifying patients with OSA. With these sex and anatomic-site specific OSA predictors/formulas and this innovative clinical method, we hope to assist other surgeons with quantitative clinical diagnosis, assessment, surgical planning, and outcome assessment tools for OSA patients.

Cross-Sectional Studies↗

PubMed2005

10th Yahya Cohen Memorial Lecture: Clinical predictors in obstructive sleep apnoea patients with computer-assisted quantitative videoendoscopic upper airway analysis.

AIM: To identify the clinical predictors and assist surgeons in their clinical management of obstructive sleep apnoea (OSA) - a prospective study with a new approach to analyse the static and dynamic upper airway morphology between patients with OSA and normal subjects. To introduce a new method of assessment for surgical outcome. MATERIALS AND METHODS: Quantitative computer-assisted videoendoscopy (validated with upper airway magnetic resonance imaging) was performed in 49 (43 males, 6 females) patients with OSA and compared with 39 (22 males, 17 females) controls (apnoea-hypopnoea index <5). Absolute cross-sectional areas, transverse and longitudinal diameters at the retro-palatal and retro-lingual levels were measured during end of quiet respiration and during Mueller's manoeuvre in the erect and supine positions, allowing us to study static and dynamic morphology (collapsibility) of the upper airway. We analysed 3744 parameters. RESULTS: In males, retro-palatal and retro-lingual areas during Mueller's manoeuvre in the supine position of 0.7981 cm2 [receiver operating characteristics (ROC) = 0.9284, positive predictive value (PPV) = 86.05%, negative predictive value (NPV) = 84.62%] and 2.0648 cm2 (ROC = 0.8183, PPV = 76%, NPV = 83.33%), respectively, were found to be good predictors/ cut-off values for OSA. Retro-palatal area measured in the supine position during Mueller's manoeuvre (AS1M) and collapsibility of retro-palatal area in the supine position calculated (CAS1) were found to have significant correlations with severity of OSA. In females, areas measured during Mueller's manoeuvre in the supine position of 0.522 cm2 at retropalatal level (ROC = 1, 100% PPV and NPV) and transverse diameter at retro-lingual level during erect Mueller's manoeuvre of 1.1843 cm (ROC = 0.9056, PPV = 100%, NPV = 83.33%) were found to be predictive. All measurements at the retro-palatal level and in the supine position had higher predictability. Area measurements obtained during Muller's manoeuvre were more predictive (ROC >0.9910) than resting measurements (ROC >0.8371). Several gender and anatomical-site specific formulas with excellent predictability (ROC close or equal to 1) were also devised. Examples of surgical outcome assessment were introduced. CONCLUSION: Upper airway Mueller's studies are predictive and useful (independent samples t-test/Mann Whitney U test, ROC) in identifying patients with OSA. With these gender and anatomical-site specific OSA predictors/formulas and this innovative clinical method, we hope to assist other surgeons with quantitative clinical diagnosis, assessment, surgical planning and outcome assessment tools for OSA patients.

Adult↗

PubMed2001

Effect of postural change on blood volume in long-term hemodialysis patients.

In healthy subjects, the blood volume (BV) increases rapidly after postural change from standing to the supine position. However, little is known about the effect of postural change on BV in long-term hemodialysis (HD) patients. Therefore, we have examined the BV change caused by adopting the supine position from standing by continuous hematocrit monitoring, using the CRIT-LINE instrument, in 8 anuric HD patients. The hematocrit was monitored for 25 min with the patient in the supine position just before HD. The percentage change in the BV (% Delta BV) was calculated from the hematocrit and approximated using the equation: % Delta BV = b - [1 - exp(-c x time (min)] -a x time (min). Coefficient a was the slope of the linear part in the % Delta BV, b was the magnitude of BV increase and c was the rate of BV increase. Then we examined the relationship between the coefficients (a, b and c) and clinical parameters. In all patients, % Delta BV increased quickly after adopting the supine position. The mean increases were 2.8 +/- 0.6% after 5 min and 4.8 +/- 0.5% after 25 min. There was a significant correlation between the value of % Delta BV calculated from the hematocrit and the value calculated using above equation (0.92 < r < 0.99, p < 0.001). Although coefficient a did not correlate with a clinical parameter, coefficient b showed a significant positive linear correlation with the serum albumin level (r = 0.816, p < 0.05) and coefficient c showed a significant positive linear correlation with the percentage change in interdialytic weight gain (r = 0.736, p < 0.05). Furthermore, based on the % Delta BV, we calculated the change in total BV, which had increased by 181.5 +/- 21.9 ml after 25 min in the supine position. In conclusion, the change in the BV with time by continuous hematocrit monitoring using the CRIT-LINE instrument can be approximated by a modified monoexponential equation. BV increased quickly in HD patients after postural change from standing to the supine position.

Aged↗

PubMed2005

Effects of body posture on local sweating and sudomotor outflow as estimated using sweat expulsion.

To estimate the effects of changes in body posture on sudomotor function, sweat rates on the forearm, chest and thigh, tympanic temperature (Tty), and skin temperatures were recorded in an upright sitting and a supine position under a hot environment of 40 degrees C Ta and 40% relative humidity for 60 min. Sweat expulsions were identified on sweat rate curves and their rates (Fsw) were calculated. Tty was higher, and its initial fall was greater, in the supine position than in the sitting position. On the forearm and the chest, the regression line relating sweat rate to mean body temperature (Tmb) had a gentler slope in the supine position, whereas on the thigh, it showed a steeper slope. The regression line relating Fsw to Tmb had a steeper slope in the supine position than in the sitting position, suggesting that the gain in the mechanisms for central integration and rhythm-generation was enhanced in the supine position. The parameter of sweat rate divided by Fsw was lower on the forearm and the chest, whereas it was higher on the thigh in the supine position than in the sitting position, suggesting that sudomotor outflow was modified at the spinal cord in association with skin pressure. It was concluded that body posture affects sudomotor functions through both brain and spinal mechanisms.

Adult↗

PubMed1995

Intractable cough associated with the supine body position. Effective therapy with nasal CPAP.

We describe five patients with severe nocturnal cough and daytime somnolence in whom the coughing attacks are triggered by assuming the supine body position. Quantity and quality of the nocturnal cough were evaluated in the sleep laboratory with and without nasal continuous positive airway pressure (N-CPAP). Air flow characteristics were assessed using flow volume and airway resistance loops. Airway anatomy was evaluated bronchoscopically. In all five patients, the cough had a barking quality. Flow-volume loops showed an expiratory collapse phenomenon in two of the patients. Endoscopically, all five patients had signs of airway collapse. All patients had difficulty falling asleep because of coughing and were awakened by it frequently. Sleep times ranged from 2.5 to 4.5 h per night. With N-CPAP pressures ranging from 5 to 13 cm H2O, all five patients had clinically significant improvement in their symptoms. Their sleep times increased to a range of 5 to 7.5 h per night and the daytime somnolence markedly improved or resolved. All five patients requested a N-CPAP unit for home use. We conclude that a cough that is predominantly associated with or exacerbated by the supine body position may be treated effectively with N-CPAP.

Adult↗

PubMedDate not supplied

[Short-term effects of prone positioning on the oxygenation of pediatric patients submitted to mechanical ventilation]

OBJECTIVE: To analyze the short-term effects of prone positioning on the oxygenation of mechanically-ventilated children suffering from severe hypoxemia. MATERIALS AND METHODS: A prospective, nonrandomized trial (each patient as his/her own control) was conducted between July 1998 and July 1999. Mechanically-ventilated children with peak inspiratory pressure greater than or equal to 30 cm H(2)O, FiO(2) greater than or equal to 0.5, and PaO(2)/FiO(2) ratio less than or equal to 200 were included in the study. Each patient was kept in the prone position for two hours, returning to the supine position after this period. Oxygenation was assessed by means of PaO(2)/FiO(2) in the supine position (one hour before prone positioning), one hour after prone positioning, and one hour after returning to the supine position. Patients who presented an increase of at least 20 in PaO(2)/FiO(2) were considered responsive. The results were compared by Student t-test, Friedman test, chi-square test, Fishers exact test, and confidence interval. RESULTS: Eighteen children (10 males), whose mean age was 11.5 -/+11.5 months, with initial PaO(2)/FiO(2) of 96.06 -/+ 41.78, participated in the study. After one hour in the prone position, 27.7% of the patients (5/18) improved their PaO(2)/FiO(2) ratio (P=0.045). Six of these patients presented reduced lung compliance (four of them had acute respiratory distress syndrome); and twelve patients showed increased airway resistance (six of them presented bronchiolitis). No significant difference was observed between these two groups (reduced lung compliance x increased airway resistance) in terms of age, sex, duration of ventilation prior to change in position, peak inspiratory pressure, FiO(2), severity of hypoxemia, and outcome. CONCLUSION: Prone positioning during mechanical ventilation of children with severe hypoxemia may improve the PaO(2)/FiO(2) ratio in the first hour.

Journal Article↗