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Results for “Supine Position”

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At least 55 records · Page 3Linked to original sources

PubMed1999

Pulmonary perfusion is more uniform in the prone than in the supine position: scintigraphy in healthy humans.

The main purpose of this study was to find out whether the dominant dorsal lung perfusion while supine changes to a dominant ventral lung perfusion while prone. Regional distribution of pulmonary blood flow was determined in 10 healthy volunteers. The subjects were studied in both prone and supine positions with and without lung distension caused by 10 cmH2O of continuous positive airway pressure (CPAP). Radiolabeled macroaggregates of albumin, rapidly trapped by pulmonary capillaries in proportion to blood flow, were injected intravenously. Tomographic gamma camera examinations (single-photon-emission computed tomography) were performed after injections in the different positions. All data acquisitions were made with the subject in the supine position. CPAP enhanced perfusion differences along the gravitational axis, which was more pronounced in the supine than prone position. Diaphragmatic sections of the lung had a more uniform pulmonary blood flow distribution in the prone than supine position during both normal and CPAP breathing. It was concluded that the dominant dorsal lung perfusion observed when the subjects were supine was not changed into a dominant ventral lung perfusion when the subjects were prone. Lung perfusion was more uniformly distributed in the prone compared with in the supine position, a difference that was more marked during total lung distension (CPAP) than during normal breathing.

Adult↗

PubMed2004

Supine position is safe and effective for percutaneous nephrolithotomy.

BACKGROUND AND PURPOSE: The prone position has been widely adopted in conventional percutaneous nephrolithotomy (PCNL). Following its introduction in 1998, we changed our routine practice of PCNL from the prone to the supine position, which had numerous benefits and was safe and effective. Tract formation and stone fragmentation and retrieval were accomplished with the patient supine. PATIENTS AND METHODS: We report our experience with 62 patients (67 renoureteral units) treated in the supine position and describe the technique in detail. RESULTS: The primary stone clearance rate was 76%, and the mean number of sessions of PCNL was 1.3. There was no procedure-related major complication. There were also no splanchnic injuries. One kidney loss (emergency nephrectomy for control of hemorrhage) was noted but was not directly related to the procedure (profuse bleeding after accidental traction on the balloon nephrostomy tube by the patient 1 week after PCNL). Modification of positioning was made to suit the body build of Chinese patients. CONCLUSION: There are several advantages to the supine position for the patient and the urologist, with greater versatility of stone manipulation along the whole upper urinary tract. There are a few limitations of the supine position, but they can be overcome. Performing PCNL with the patient in the supine position is a sound alternative to the conventional prone position.

Adult↗

PubMed2000

Sequential changes of arterial oxygen tension in the supine position during one-lung ventilation.

UNLABELLED: To investigate how surgical positions affect the severity and progress of hypoxemia during one-lung ventilation (OLV), we studied 33 adult patients undergoing right thoracotomy with left OLV. The patients were divided into three groups according to the positions during surgery as follows: the supine position (SP) group (n = 11), the left semilateral decubitus position (LSD) group (n = 9), and the left lateral decubitus position (LLD) group (n = 13). Analysis of arterial blood gases was sequentially determined every 5 min for 30 min during OLV (fractional ratio of inspiratory oxygen = 1.0) in each position. OLV was promptly terminated and switched to bi-lung ventilation if Spo2 declined to 90%. Pao2 progressively decreased with time in all three groups (P < 0.01). The incidence of termination of OLV within 30 min was higher in the SP group (82%), compared with that in the LSD (11%) and LLD (8%) groups (P < 0.01). Final Pao2 (65+/-12 mm Hg, mean +/- SD, P < 0.01 versus LLD, P < 0.05 versus LSD) and SaO2 (91%+/-4%, P < 0.01 versus LLD and LSD) at the termination of OLV in the SP group were the lowest. There was no difference between these values in the LSD and LLD groups (128+/-54 mm Hg, 96%+/-2%, and 167+/-69 mm Hg, 97%+/-4%, respectively) 30 min after the start of OLV. The time for Pao2 to decrease to 200 mm Hg calculated from each regression curve was 354 s in the SP group, 583 s in the LSD group, and 798 s in the LLD group. The time for Pao2 to decline to 100 mm Hg was 794 s in the SP group. In the regression curves of the LSD and LLD groups, the Pao2 did not decrease to 100 mm Hg. Heart rate was slow at baseline in the SP group (P < 0.05 versus LSD), but other hemodynamic variables did not differ among the three groups throughout this study. The LSD was as effective as the LLD in avoiding life-threatening hypoxemia during OLV. IMPLICATIONS: Close observation and prompt counteractions including termination of one-lung ventilation (OLV) are crucial for patients under OLV in the supine position, because life-threatening hypoxemia frequently occurs approximately 10 min after starting OLV, even under 100% oxygen inhalation. The left semilateral decubitus position was as effective as the left lateral decubitus position in avoiding life-threatening hypoxemia during OLV.

Blood Gas Analysis↗

PubMed2003

Quadriceps femoris torque and EMG activity in seated versus supine position.

PURPOSE: To compare voluntary and electrically evoked knee extensor torque, surface electromyography (EMG), and activation level obtained under seated versus supine position, i.e., with shortened versus lengthened rectus femoris (RF) muscle. METHODS: The knee extensor torque obtained during maximal voluntary contractions (MVC) and after single and paired stimuli applied at rest was measured under seated (i.e., 90 degrees hip angle) and supine (i.e., 180 degrees hip angle) conditions. The associated EMG activity from biarticular RF and monoarticular vasti was also recorded, and activation level was estimated by means of the twitch interpolation technique. RESULTS: Knee extensor MVC was 10.6% higher in the seated compared with the supine position (P < 0.01). EMG normalized to the M-wave amplitude for respective muscles and for respective positions was significantly lower under supine conditions, and deficits averaged approximately 20% for vasti and approximately 41% for RF (P < 0.05). Similarly, activation level estimated in the supine position was approximately 4% lower than the seated counterpart. Relative MVC losses observed supinely were significantly correlated with the corresponding activation level deficits (P < 0.05). On the other hand, both single and paired stimuli resulted in higher torque amplitudes in the supine with respect to the seated position, and mean differences were comprised between 10% (single twitch, P < 0.05) and 20% (potentiated doublet, P < 0.001). RF M-wave amplitude recorded supinely was 19% higher than the seated counterpart (P < 0.01). CONCLUSION: The higher neural activation observed for the knee extensor muscles in the seated versus supine position, likely attributable to improved motor unit recruitment, may reflect a neurophysiological mechanism partly compensating the neuromuscular transmission-propagation impairment and/or mechanical disadvantage of shortened RF muscle.

Adult↗

PubMed1985

Rearranged automated keratometer for newborn infants and patients in the supine position.

To measure corneal curvature in newborn infants and patients in the supine position, we rearranged an automated keratometer, dividing it into two parts, the power unit and the measuring system. The measuring unit was mounted on a universal stand. We observed no difference in measured value between the sitting and supine positions and no difference in maneuverability. We also examined the effect of a speculum in normal adult subjects in the supine position, in which both the strong and the weak radii and the axis of astigmatism were slightly affected. However, there was no significant difference in the mean values of the strong and weak radii of corneal curvature in 22 eyes of infants with corrected gestational ages of 37 to 43 weeks. The examination was carried out with ease. The mean value of corneal curvature was 7.05 mm and the range was 6.63 to 7.74 mm.

Adult↗

PubMed2001

[Comparison between the anterior chamber configuration in the supine position and that in the prone position in patients with narrow angle].

PURPOSE: To determine whether the anterior chamber configuration of patients with narrow angle is changed in the prone position. PATIENTS AND METHODS: The study included 16 eyes of 16 patients whose anterior chamber angle was classified as Shaffer 2 or narrower. The prone position test(PPT) and ultrasound biomicroscopy (UBM) were performed on every subject. In the UBM examination, the following parameters were measured both in the supine position and in the prone position: the angle-opening distance at 250 microns from scleral spur(AOD 250), the angle-opening distance at 500 microns from scleral spur(AOD 500), the trabecular-iris angle(TIA), and the anterior chamber depth at the center of the cornea(anterior chamber depth, ACD). RESULTS: While the intraocular pressure was higher after PPT than before the test, every subject was evaluated as negative for PPT. Mean value of every parameter examined was lower in the prone position than in the supine position(AOD 250: 114 microns, vs. 128 microns, AOD 500: 121 microns vs. 144 microns, TIA: 12.1 degrees vs. 15.5 degrees, ACD: 1966 microns vs. 2002 microns), and the change in ACD was statistically significant (p = 0.013). CONCLUSIONS: The anterior chamber configuration of patients with narrow angle is changed in prone position. Such a change can occur in patients classified as negative for PPT.

Aged↗

PubMedDate not supplied

[Repair of a vesicovaginal fistula in the ventral supine position (34 cases)].

The authors report the efficacy of a transvaginal approach in the ventral supine position for repair of vesicovaginal fistula based on a series of 34 consecutive patients. 34 patients, between the ages of 15 and 60 years, with vesicovaginal fistula (cervicotrigonal in one half of cases) of obstetric origin (73% of dystocia) in multiparous women (62% were treated by transvaginal closure of the fistula in the ventral supine position). 29 complete successes were obtained with 5 residual fistulae which were lost to follow-up. The use of the ventral supine position is valuable in the transvaginal repair of vesicovaginal fistulae.

Adolescent↗

PubMed1979

The effect on dosimetry of changing from the lithotomy to the supine position in treating uterine cancer with the Cathetron and external radiotherapy.

Uterine carcinoma can be treated by combined external and intracavitary irradiation. With an afterloading technique intracavitary irradiation is given with the patients in the lithotomy position. External irradiation is given with the patient in the supine position. A lead shield is used with the external fields to cover the tissues which are close to the intracavitary sources and receive high doses. The positions of the intracavitary sources seen on radiographs taken when the patient is in the lithotomy position are transferred to films taken with the patient in the supine position. From the latter the position and profile of the shield are calculated. It is shown that a reliable transfer of the positions of the sources and determination of the necessary shielding cannot be achieved in this way. It is therefore concluded that both intracavitary and external irradiation should be carried out with the patient in the supine position.

Cobalt Radioisotopes↗

PubMed1992

[Unexpected air embolism during an aneurysmal operation in supine position--a case report and a speculation about its pathogenesis].

The occurrence of air embolism in supine position operation is extremely rare. We reported a case of air embolism during the operation of a ruptured middle cerebral artery aneurysm in supine position. A 58-year-old woman was admitted to our hospital in semicomatous state. A CT scan revealed diffuse subarachnoid hemorrhage. Cerebral angiogram showed a middle cerebral artery aneurysm. Massive pinkish foamy sputum and butterfly shadow on chest x-ray strongly suggested an association of neurogenic pulmonary edema (NPE). Barbiturate therapy and controlled ventilation with positive end-expiratory pressure (5cmH2O) were started. Her airway pressure was about 35cmH2O. Decrease of pinkish foamy sputum and an improvement of chest x-ray findings on the next day encouraged us to perform a clipping operation. Just before a clip application, air bubbles were observed to pass through the middle cerebral artery under the microscope. Subsequently cardiac standstill was brought out. Fortunately, she was resuscitated, and a clip application was finished. A postoperative CT scan revealed an infarction in the middle cerebral artery area. A postoperative cerebral angiogram showed occlusion of a temporal branch of the right middle cerebral artery, P1 portion of the left posterior cerebral artery, and the right superior cerebellar artery. We speculated that high endotracheal pressure brought out pulmonary alveolar rupture, and in spite of supine position operation massive air, which flowed into systemic circulation from ruptured alveoli, caused cerebral infarction and cardiac arrest. We consider that unrecognized air embolism might be the one of the factors influencing the prognosis of severe subarachnoid hemorrhage, especially in the cases associated with neurogenic pulmonary edema.

Embolism, Air↗

PubMed2006

Lung and 'end organ' injury due to mechanical ventilation in animals: comparison between the prone and supine positions.

INTRODUCTION: Use of the prone position in patients with acute lung injury improves their oxygenation. Most of these patients die from multisystem organ failure and not from hypoxia, however. Moreover, there is some evidence that the organ failure is caused by increased cell apoptosis. In the present study we therefore examined whether the position of the patients affects histological changes and apoptosis in the lung and 'end organs', including the brain, heart, diaphragm, liver, kidneys and small intestine. METHODS: Ten mechanically ventilated sheep with a tidal volume of 15 ml/kg body weight were studied for 90 minutes. Five sheep were placed in the supine position and five sheep were placed in the prone position during the experiment. Lung changes were analyzed histologically using a semiquantitative scoring system and the extent of apoptosis was investigated with the TUNEL method. RESULTS: In the supine position intra-alveolar hemorrhage appeared predominantly in the dorsal areas, while the other histopathologic lesions were homogeneously distributed throughout the lungs. In the prone position, all histological changes were homogeneously distributed. A significantly higher score of lung injury was found in the supine position than in the prone position (4.63 +/- 0.58 and 2.17 +/- 0.19, respectively) (P < 0.0001). The histopathologic changes were accompanied by increased apoptosis (TUNEL method). In the supine position, the apoptotic index in the lung and in most of the 'end organs' was significantly higher compared with the prone position (all P < 0.005). Interestingly, the apoptotic index was higher in dorsal areas compared with ventral areas in both the prone and supine positions (P < 0.003 and P < 0.02, respectively). CONCLUSION: Our results suggest that the prone position appears to reduce the severity and the extent of lung injury, and is associated with decreased apoptosis in the lung and 'end organs'.

Animals↗

PubMed2002

Haemodynamic changes during neck pressure and suction in seated and supine positions.

We sought to quantify the contribution of cardiac output (Q) and total vascular conductance (TVC) to carotid baroreflex-mediated changes in mean arterial pressure (MAP) in the upright seated and supine positions. Acute changes in carotid sinus transmural pressure were evoked using brief 5 s pulses of neck pressure and neck suction (NP/NS) via a simplified paired neck chamber that was developed to enable beat-to-beat measurements of stroke volume using pulse-doppler ultrasound. Percentage contributions of Q and TVC were achieved by calculating the predicted change in MAP during carotid baroreflex stimulation if only the individual changes in Q or TVC occurred and all other parameters remained at control values. All NP and NS stimuli from +40 to -80 Torr (+5.33 to -10.67 kPa) induced significant changes in Q and TVC in both the upright seated and supine positions (P < 0.001). Cardiopulmonary baroreceptor loading with the supine position appeared to cause a greater reliance on carotid baroreflex-mediated changes in Q. Nevertheless, in both the seated and supine positions the changes in MAP were primarily mediated by alterations in TVC (percentage contribution of TVC at the time-of-peak MAP, seated 95 +/- 13, supine 76 +/- 17 %). These data indicate that alterations in vasomotor activity are the primary means by which the carotid baroreflex regulates blood pressure during acute changes in carotid sinus transmural pressure.

Adaptation, Physiological↗

PubMed1999

Craniospinal axis irradiation in children. Treatment in supine position including field verification as a prerequisite for anesthesia without intubation.

PURPOSE: For craniospinal axis irradiation in young children sometimes anesthesia is required. In order to minimize risks from the anesthesist's point of view supine position would be preferable to standard prone position. In case of irradiation in supine position verification of the 3-field junction in the cervical region causes problems, because there is no direct visual control. For such situations the clinical application of a new technique is presented. PATIENTS AND METHODS: For treatment planning a modern 3D planning system was necessary. Patient's positioning was done by using a vacuum-form body immobilizer and an integrated head mask. Radiation fields were placed only by table movements being calculated by the planning system in relation to a reference point at the patient's surface. In addition to common verification films specially prepared small films were used for the 3-field junction in the cervical region. These films were placed close to the patient for the whole time of each radiation session being exposed by every radiation field. RESULTS: Two children (age 3 and 5 years, respectively) were irradiated as described. Twenty-eight of those specially prepared films were exposed. Two films (7%) had to be excluded because of inadequate exposure. An overlap of radiation fields was seen on 1 of the 26 remaining films (4%), whereas an unacceptable gap was not found. Acute skin reactions were comparable to those observed in patients being irradiated in standard prone position. CONCLUSION: The presented technique for craniospinal axis irradiation in supine position including field verification was not only precise and reproducable, but also comfortable and safe for the patient. We suggest it as a new option for craniospinal axis irradiation in children.

Anesthesia, General↗

PubMed2002

Reproducibility of mammary gland structure during repeat setups in a supine position.

PURPOSE: In breast conserving therapy, complete excision of the tumor with an acceptable cosmetic outcome depends on accurate localization in terms of both the position of the lesion and its extent. We hypothesize that preoperative contrast-enhanced magnetic resonance (MR) imaging of the patient in a supine position may be used for accurate tumor localization and marking of its extent immediately prior to surgery. Our aims in this study are to assess the reproducibility of mammary gland structure during repeat setups in a supine position, to evaluate the effect of a breast immobilization device, and to derive reproducibility margins that take internal tissue shifts into account occurring between repeat setups. MATERIALS & METHODS: The reproducibility of mammary gland structure during repeat setups in a supine position is estimated by quantification of tissue shifts in the breasts of healthy volunteers between repeat MR setups. For each volunteer fiducials are identified and registered with their counter locations in corresponding MR volumes. The difference in position denotes the shift of breast tissue. The dependence on breast volume and the part of the breast, as well as the effect of a breast immobilization cast are studied. RESULTS: The tissue shifts are small with a mean standard deviation on the order of 1.5 mm, being slightly larger in large breasts (V> 1000 cm3), and in the posterior part (toward the pectoral muscle) of both small and large breasts. The application of a breast immobilization cast reduces the tissue shifts in large breasts. A reproducibility margin on the order of 5 mm will take the internal tissue shifts into account that occur between repeat setups. CONCLUSION: The results demonstrate a high reproducibility of mammary gland structure during repeat setups in a supine position.

Adult↗

PubMed1982

Normal values of functional residual capacity in the sitting and supine positions.

The measurement of functional residual capacity (FRC) has assumed new importance in the diagnosis of acute respiratory failure. However few reference values exist for FRC in supine positions for both sexes. We measured the FRC in 100 healthy subjects with the helium dilution closed circuit method in the sitting and supine positions. There were 50 women aged 20 to 63 years and 50 men aged 22 to 65 years. Fifty five subjects were smokers (25 women and 30 men) but no significant differences were found between FRC of smokers and nonsmokers. The FRC always decreased when the subject changed from the sitting to supine position. In this study, the correlation coefficients between FRC and height were statistically significant for both sexes, the influence of age and weight on FRC being negligible. Our results provide useful reference values for FRC in the supine position.

Adult↗

PubMed2004

Cephalometric comparison of pharyngeal changes in subjects with upper airway resistance syndrome or obstructive sleep apnoea in upright and supine positions.

The aim of the present study was to cephalometrically compare pharyngeal changes between upright and supine positions in patients with upper airway resistance syndrome (UARS) or obstructive sleep apnoea (OSA). Eighty-two OSA patients, 70 men (mean age 49 +/- 11.8 years) and 12 women (45.9 +/- 8.3 years), underwent cephalometric sleep apnoea analysis. One upright and one supine radiograph were taken of each patient (a total of 164 cephalometric radiographs). The results showed no significant changes either in naso- or hypopharyngeal soft tissues between the two positions. In contrast, the shortest distance from the soft palate (ve1-ve2) and the tip of the soft palate (u1-u2) to the posterior oropharyngeal wall was significantly narrower (P < 0.001) in the supine position. Furthermore, in the supine position a slight thickening in the soft palate (sp1-sp2, P < 0.05) was detected with no change in the length of the soft palate (PNS-u1). The form of the tongue changed significantly: it was shorter (Tt-Tgo, P < 0.001; Tt-va, P < 0.001) and thicker (Ts/Tt-Tgo, P < 0.05) in the supine position. The present results suggest that OSA patients are prone to significant narrowing of their oropharyngeal, but not of their naso- or hypopharyngeal, airways in the supine position. Thus, treatment of OSA and UARS patients should mainly be aimed at preventing further oropharyngeal airway narrowing as a result of supine-dependent sleep.

Adolescent↗

PubMed2000

Goal directed reaching and postural control in supine position in healthy infants.

The present study focussed on the development and interaction of reaching and posture in supine position in young infants. The kinematics of goal directed reaches and the concurrent ground reaction forces of the total body centre of pressure (COP) in cranial-caudal and medial-lateral direction were recorded in twelve healthy fullterm infants at 4 and 6 months of age. From eight infants, data were available at both ages. The results indicated that between 4 and 6 months, postural stability during reaching in supine position increased, as the oscillatory COP displacement in the medial-lateral direction decreased significantly with increasing age. Concurrently, reaching performance improved, which was reflected by a decrease in the number of movement units (MU), the length of the displacement-path of the hand and an increase of the length and duration of the first MU. The kinematic data of the reaching movements and the COP data were correlated at both ages, but the nature of the relation changed. At 4 months of age, the number of MU was related to the number of COP oscillations in the cranial-caudal direction, whereas at 6 months the maximum velocity of the hand movement was related to the maximum velocity of COP displacement in cranial-caudal and medial-lateral direction. This change might point to the development of a more subtle control of postural adjustments during reaching movements in supine position.

Aging↗

PubMed2000

Is there significance of the choice of prone versus supine position in the treatment of proximal ureter stones with extracorporeal shock wave lithotripsy?

OBJECTIVE: To determine whether there is a significance of the choice of prone versus supine position in the treatment of proximal ureter stones with extracorporeal shock wave lithothripsy (ESWL). METHODS: Ninety-six patients with proximal ureter stones underwent ESWL. The procedure was performed in the supine position in 48 of them (group 1) and in the prone position in the other 48 patients (group 2). Stone-free rates, repeat ESWL rates, shocks per patient and shocks per session were compared in both groups. RESULTS: The mean session number per patients was 1.64+/-0.75 in group 1 and 1. 33+/-0.59 in group 2 (p = 0.224). The stone-free rates 3 months after ESWL were 88.3% in group 1 and 90.6% in group 2. The difference between the results was statistically insignificant (p<0.05). Therefore, these two parameters were similar in both groups. On the other hand, the number of shocks per session was 4,863.54+/-2, 114.85 in group 1 and 3,704.16+/-1,726.75 in group 2. This difference was statistically significant (p = 0.011). The patients tolerated the supine position better in general. Patients in the prone position experienced discomfort on inspiration and expiration and pain localized to the lumbar vertebrae. CONCLUSION: These results suggest that the supine position decreases the number of shocks per session in the treatment of proximal ureter stones with ESWL and this will be cost-effective.

Humans↗

PubMed2006

Dosimetric and toxicity comparison between prone and supine position IMRT for endometrial cancer.

PURPOSE: To determine the dosimetric and toxicity differences between prone and supine position intensity-modulate radiotherapy in endometrial cancer patients treated with adjuvant radiotherapy. METHODS: Forty-seven consecutive endometrial cancer patients treated with adjuvant RT were analyzed. Of these, 21 were treated in prone position and 26 in the supine position. Dose-volume histograms for normal tissue structures and targets were compared between the two groups. Acute and chronic toxicity were also compared between the cohorts. RESULTS: The percentage of volume receiving 10, 20, 30, 40, 45, and 50 Gy for small bowel was 89.5%, 69%, 33%, 12.2%, 5%, and 0% in the prone group and 87.5%, 62.7%, 26.4%, 8%, 4.3%, and 0% in the supine group, respectively. The difference was not statistically significant. The dose-volume histograms for bladder and rectum were also comparable, except for a slightly greater percentage of volume receiving 10 Gy (1.5%) and 20 Gy (5%) for the rectum in the prone group. Acute small bowel toxicities were Grade 1 in 7 patients and Grade 2 in 14 patients in the prone group vs. Grade 1 in 6 patients and Grade 2 in 19 patients in the supine group. Chronic toxicity was Grade 1 in 7 patients and Grade 3 in 1 patient in the prone group and Grade 1 in 5 patients in the supine group. CONCLUSION: These preliminary results suggest that no difference exists in the dose to the normal tissue and toxicity between prone and supine intensity-modulated radiotherapy for endometrial cancer. Longer follow-up and more outcome studies are needed to determine whether any differences exist between the two approaches.

Adult↗