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Results for “Prone Position”

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PubMed2002

Percutaneous nephrolithotomy in the supine position: technical aspects and functional outcome compared with the prone technique.

OBJECTIVES: To compare the results of percutaneous nephrolithotomy in the supine and prone positions. METHODS: A total of 130 patients who underwent percutaneous nephrolithotomy for renal or upper ureteral stones were evaluated in a prospective and nonrandomized manner. The procedure was carried out in the supine or prone position in 53 and 77 patients, respectively. The results in both positions were compared regarding the technical aspects, success rate, and morbidity. RESULTS: Regardless of the position, the pelvicaliceal system could be successfully approached in all patients, and the posterior calices were the most common site of entry. Punctures through the anterior calices were more frequently reported with the supine position. A higher incidence of anteromedial displacement of the kidney during tract dilation was reported with the supine approach. The overall success rate was 89% and 84% in the supine and prone positions, respectively. The complication rates were similar in both groups, and none of the patients experienced injury of adjacent organs. CONCLUSIONS: The approach to the pelvicaliceal system is feasible in the supine position. The success and complication rates are comparable to the prone approach.

Adult↗

PubMed1996

Clinical trials: testing of adult chemical heating pad.

Chemical packs are recent innovations in the delivery of dry heat. Because these delivery systems do not have any mechanism for verifying temperature during application, research to determine their safety seems warranted. The purpose of this study was to measure the skin temperature of adults during a 30-minute application of the MediHeat adult heating pad (MH-AHP). Seventy-seven subjects received a 30-minute application of the MH-AHP to their backs while lying in both supine and prone positions. The mean skin temperature in both positions was 101 degrees F. There were significant differences, however, in minimum and maximum skin temperature between positions. Subjects in the prone position had significantly higher maximum skin temperature and significantly lower minimum skin temperature than subjects in the supine position. It is possible that the prone position allows for more air flow over the MH-AHP and that more heat was generated causing the higher maximum temperature. This explanation does not account for the lower minimum temperature. There were no significant differences in perception of heat between the positions at either 5 minutes or 30 minutes. Findings suggest that caution is necessary when applying heating devices that depend on air circulation for heat generation.

Adult↗

PubMed2004

Dosimetric analysis of a simplified intensity modulation technique for prone breast radiotherapy.

PURPOSE: Prone-position breast radiotherapy (RT) has been described as an alternative technique to improve dose homogeneity for women with large, pendulous breasts. We report the feasibility and dosimetric analysis of a simplified intensity-modulated RT (IMRT) technique, previously reported for women in the supine treatment position, to plan prone-position RT to the intact breast. METHODS AND MATERIALS: Twenty patients with clinical Stage TisN0-T1bN1 breast cancer undergoing breast-conserving therapy underwent whole breast RT using a prone position technique. The treatment plans were developed using both conventional tangents and a simplified intensity-modulated tangential beam technique based on optimization of the intensity distributions across the breast. The plans were compared with regard to the dose-volume parameters. RESULTS: Dose heterogeneity within the breast planning target volume was significantly greater for the conventional tangent plans. Of 20 patients, 16 (80%) received maximal doses of > or =110% using the conventional tangents vs. only 1 (5%) using the IMRT plan. The isodose level encompassing 5% of the planning target volume was reduced from an average of 110% with conventional tangents to 105% with IMRT. The maximal dose within the planning target volume was reduced from an average of 114% with conventional tangents to 107% with IMRT. The greatest improvement was seen in the patients with the most pendulous breasts. CONCLUSION: An IMRT planning approach is feasible for prone-position breast RT and improves dose homogeneity, particularly in women with larger, pendulous breasts. Additional follow-up is necessary to determine whether the improvements in dose homogeneity impact acute toxicity and cosmetic outcome in this cohort of women who have historically suffered from poor cosmesis after breast-conserving therapy.

Adult↗

PubMed2000

Effect of positioning on respiratory synchrony in non-ventilated pre-term infants.

BACKGROUND AND PURPOSE: Body position can play an important role in an infant's recovery from respiratory disease, but few studies have accounted for sleep state which is known to have a direct influence on the control of respiratory muscles as well as on metabolic and circulatory changes. The purpose of this study was to examine the influence of body position on respiratory function in pre-term infants whilst accounting for sleep state. METHOD: Thoraco-abdominal motion was assessed using respiratory inductance plethysmography (RIP) to provide measures of relative rib cage (RC) and abdominal (AB) movement in ten non-ventilated pre-term infants. Continuous measurements of oxygen saturation (SaO2), pulse and heart rate (HR), were made and sleep state was recorded using behavioural criteria and electro-oculogram (EOG) measurements. RESULTS: The results showed a significant increase in HR in supine, but no significant difference in SaO2 as a function of position, compared to the prone position where a significant reduction was found in thoraco-abdominal asynchrony for both groups and a reduction in variability in both HR and SaO2. Intra-subject variability of thoraco-abdominal motion as a function of position demonstrated no significant difference on return to supine or on return to prone, illustrating good repeatability of measures. CONCLUSIONS: Prone positioning of pre-term infants recovering from respiratory disease may improve respiratory function. As measured, the improvement in respiratory synchrony in prone position brings pre-term infants' breathing pattern into line with that expected in term infants.

Cross-Over Studies↗

PubMed2005

"Supine-prone" dynamic X-ray examination: new method to evaluate low-grade lumbar spondylolisthesis.

Lumbar instability often causes clinical symptoms, and spondylolisthesis is a main factor of the low back pain. Segmental lumbar instability generally is due to a degenerative or listhesic process of the lumbar spine and radiological imaging is essential to diagnose it. Lumbar spine segmental mobility has commonly been studied by dyanamic radiographic methods. Dynamic X-rays, with maximal extension and flexion of the lumbar tract, represents the most widely used technique and a valid method to estimate sagittal segmental lumbar motion. Between 1998 and 2002 we treated 75 patients for low-grade spondylolisthesis. All patients underwent a preoperative dynamic X-rays examinination, to evaluate the degree of the lumbar mobility. We report a supine-prone position as new method to clearly estimate the slipping of lumbar vertebrae. The patients had a standard lateral X-rays film in the supine position, and then in the "prone" position. We compared the two methods and we found a higher degree of listhesis in 19 cases (14 I grade, 5 I-II grade), while there was no difference in 56 cases. The higher degree of listhesis was in the prone position. We believe that the supine-prone position is an economic method and should be mandatory performing a dynamic X-rays examination.

Humans↗

PubMed1990

Significance of exercise and bed rest in pregnancy--study on the lying postures of gravidas during sleep (2).

For the purpose of determining the most reasonable lying posture for pregnant women, we investigated the lying positions of both 247 non-pregnant women and 302 pregnant women during sleep. As for the rate of each position during the entire period of observation, 33.2% of the non-pregnant women were in the supine position, 41.2% in the lateral position, 18.4% in Sims' position and 7.1% in the prone position. In the pregnant group, the rate of supine position, simple lateral position and Sims' position was 34.2%, 52.2% and 12.7%, respectively, but the rate of the prone position was limited to 0.8%. All of the gravidas assuming the prone position were at less than 16 weeks of gestation. Non-pregnant women could sleep in a variety of positions, but pregnant women could assume the prone position during sleep only in the stage when the abdomen is not yet prominent or distended. Pregnant women were restricted significantly, either consciously or unconsciously, with progress in gestation.

Adult↗

PubMedDate not supplied

Effect of position on pulmonary mechanics in healthy preterm newborn infants.

Preterm infants are often placed in the supine position to facilitate care and observation. Prone positioning may positively affect later neurodevelopmental outcome, but it may also affect pulmonary function. Using a computerized system, we examined the effect of positioning on pulmonary mechanics in spontaneously breathing healthy preterm infants. Eleven infants with a mean birth weight (+/- SD) of 1523 +/- 171 gm and a mean gestational age (+/- SD) of 31.7 +/- 1.5 weeks were studied during the first 2 weeks of life. Pulmonary mechanic measurements were obtained in both supine and prone positions by mask pneumotachography and esophageal balloon technique. Respiratory rate and oxygen saturation were unaffected by positioning. There was a statistically, but not clinically, significant increase in heart rate in the prone position. However, there were no significant differences in tidal volume, minute ventilation, pulmonary resistance, or dynamic compliance between positions. The contribution of intrasubject variability of serial measurements was assessed in a separate group of four infants studied three times in the same position. There was no significant difference in respiratory rate, tidal volume, dynamic compliance per kilogram, or total pulmonary resistance in the same infant when studied in the same position over time (p > or = 0.24). The maximum variability (95% confidence limit) was 25.5% for tidal volume, 21% for dynamic compliance, and 44.3% for resistance. Because prone positioning did not adversely affect pulmonary mechanics or oxygen saturation in these healthy preterm infants, we suggest that prone position be used to facilitate the developmental needs of these infants.

Birth Weight↗

PubMed2006

CT urography: a comparison of strategies for upper urinary tract opacification.

A consensus is yet to be reached regarding the best strategy for ensuring maximum ureteric delineation during CT urography (CTU). In this study we have compared various CTU protocols to try to establish the best method for ureteric delineation. Saline infusion in the supine position, saline infusion in the prone position, furosemide administration (10 mg, iv) and buscopan administration (20 mg iv) with saline infusion in the prone position were tried in four groups, each having 15 patients who were undergoing CTU. The pelvicalyceal system and ureter were divided into six segments, to each of which an opacification score was assigned (0, unopacified segment; 1, less than 50% opacified segment; 2, 50-99% of the segment opacified; or 3, completely opacified segment) and the results compared. Furosemide administration resulted in complete opacification of 93% of the ureters (28 of 30). In the distal (below the sciatic notch) ureter, the mean score with furosemide was 2.9, while that with saline, supine and prone positioning was 1.87 and 1.83, respectively, and this difference was highly significant (P = 0.0002 and P = 0.0001). It was also significantly higher than the buscopan group (score 2.3, P = 0.002). Also in the lower (the iliac crest to the sciatic notch) and upper (above the iliac crest) ureter, furosemide had significantly higher scores than saline infusion in either position. Saline infusion in the supine and prone positions had very similar scores in all segments that were less than the buscopan group, but this difference was not statistically significant. During CT urography, furosemide administration in low doses is the most effective and convenient technique for ureteric opacification.

Adolescent↗

PubMed1998

Transoesophageal echocardiography during scoliosis repair: comparison with CVP monitoring.

PURPOSE: Accurate haemodynamic assessment during surgical repair of scoliosis is crucial to the care of the patient. The purpose of this study was to compare transoesophageal echocardiography (TEE) with central venous pressure monitoring in patients with spinal deformities requiring surgery in the prone position. METHODS: Twelve paediatric patients undergoing corrective spinal surgery for scoliosis/kyphosis in the prone position were studied. Monitoring included TEE, intra-arterial and central venous pressure monitoring (CVP). Haemodynamic assessment was performed prior to and immediately after positioning the patient prone on the Relton-Hall table. Data consisted of mean arterial blood pressure (mBP), heart rate (HR), CVP, left ventricular end-systolic and end-diastolic diameters (LVESD and LVEDD respectively) and fractional shortening (FS). Right ventricular (RV) function and tricuspid regurgitation (TR) were assessed qualitatively. Analysis was performed using descriptive statistics, Student's t test, sign rank, and correlation analysis. RESULTS: There was an increase in CVP (8.7 mmHg to 17.7 mmHg; P < .01), and decreases in LVEDD (37.1 mm to 33.2 mm; P < .05), and mean blood pressure (75.0 mmHg to 65.7 mmHg; P < .05) when patients were placed in the prone position. Fractional shortening, LVESD, and HR did not change from the supine to the prone position. Right ventricular systolic function and tricuspid regurgitation were unchanged. CONCLUSION: These data indicate that the CVP is a misleading monitor of cardiac volume in patients with kyphosis/scoliosis in the prone position. This is consistent with previous studies. In this clinical situation, TEE may be a more useful monitoring tool to assess on-line ventricular size and function.

Adolescent↗

PubMed2001

Association between sudden infant death syndrome and prone sleep position, bed sharing, and sleeping outside an infant crib in Alaska.

OBJECTIVE: To determine the contribution of prone sleeping, bed sharing, and sleeping outside an infant crib to sudden infant death syndrome (SIDS). METHODS: We conducted a retrospective descriptive study of all SIDS cases in Alaska from January 1, 1992, through December 31, 1997. Reviewed data sources included maternal and infant medical records, autopsy reports, birth and death certificates, police and state trooper death scene investigations, and occasionally home interviews. RESULTS: The death certificate identified SIDS as a cause of death for 130 infants (cause-specific infant mortality rate: 2.0 per 1000 live births). Among infants for whom this information was known, 113 (98%) of 115 were found in the prone position, sleeping outside an infant crib, or sleeping with another person. By contrast, 2 (1.7%) were found alone and supine in their crib (1 of whom was found with a blanket wrapped around his face). Of 40 infants who slept with a parent at the time of death, only 1 infant who slept supine with a non-drug-using parent on an adult nonwater mattress was identified. CONCLUSION: Almost all SIDS deaths in Alaska occurred in association with prone sleeping, bed sharing, or sleeping outside a crib. In the absence of other risk factors, SIDS deaths associated with parental bed sharing were rare.

Adult↗

PubMedDate not supplied

[Effect of preterm infant position on weaning from mechanical ventilation].

OBJECTIVE: To determine the effects of prone positioning on cardiorespiratory stability and weaning outcome of preterm infants during weaning from mechanical ventilation. METHODS: From January to December 1999, a sample of 42 preterm infants, with birthweight < 2,000 g, mechanically ventilated in the first week of life, were randomly divided, in the beginning of the weaning process, into two groups according to the position: supine position (n = 21) or prone position (n = 21). Heart rate, respiratory rate, transcutaneous oxygen saturation and ventilatory parameters were recorded every one hour. Length of the weaning process and complications were also assessed. RESULTS: In both groups the mean gestational age was 29 weeks, most of the patients presented very low birthweight and respiratory distress syndrome. The mean length of the weaning process was 2 days. There were no differences between the groups regarding respiratory rate, heart rate and transcutaneous oxygen saturation, however, oxygen desaturation episodes were more frequent in supine position (p = 0.009). Ventilatory parameters decreased faster and reintubation was less frequent in the prone group (4% versus 33%). No adverse effects of prone positioning were observed. CONCLUSION: These results suggest that prone position is a safe and beneficial procedure during weaning from mechanical ventilation and may contribute to weaning success in preterm infants.

Female↗

PubMed2001

The prone sleeping position impairs arousability in term infants.

OBJECTIVE: To investigate whether the prone sleeping position impaired arousal from sleep in healthy infants and whether this impairment was related to cardiorespiratory variables, temperature, or age. STUDY DESIGN: Healthy term infants (n = 24) were studied with daytime polysomnography on 3 occasions: 2 to 3 weeks after birth, 2 to 3 months after birth, and 5 to 6 months after birth. Multiple measurements of arousal threshold (cm H(2)O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep and quiet sleep when infants slept both prone and supine. RESULTS: Arousal thresholds were significantly higher in both active sleep and quiet sleep when infants slept prone at 2 to 3 weeks and 2 to 3 months, but not at 5 to 6 months. These increases were independent of any sleep position-related change in either rectal or abdominal skin temperature, respiratory rate, oxygen saturation, or heart rate. CONCLUSIONS: The prone position significantly impairs arousal from both active sleep and quiet sleep in healthy term infants. This impairment in arousability occurred with no clinically significant changes in cardiorespiratory variables or body temperature. Decreased arousability from sleep in the prone position provides an important insight into its role as a risk factor for sudden infant death syndrome.

Arousal↗

PubMed1991

Prospective cohort study of prone sleeping position and sudden infant death syndrome.

Studies of the link between prone sleeping position and sudden infant death syndrome have been criticised on grounds of recall bias and for not taking into account possible confounding effects. To avoid recall bias and to allow measurement of important biological factors a prospective cohort study of the cause of sudden infant death syndrome (SIDS) is being conducted. The infants included are those at high risk of the syndrome as assessed by a perinatal score. Of the 3110 members of the cohort born between January, 1988, and end of March, 1990, 23 infants later died of SIDS. Sleep position information was available for 15 of these. Matched analysis to control for the confounding effects of infant birthweight and maternal age indicated that prone sleeping position was associated with an increased risk of SIDS (OR 4.47 95% Cl [1.30-15.43]). The findings are strengthened by the results of a concurrent retrospective case-control study of 42 SIDS cases in which the prone position was also associated with an increased risk of SIDS (unadjusted OR 3.45 [1.59-7.49]).

Case-Control Studies↗

PubMed2005

Hypotension associated with prone body position: a possible overlooked postural hypotension.

Conditions related to the dysregulation of blood pressure (BP), such as orthostatic hypotension, have been shown to be significantly associated with cardiovascular disease. Recently, the prone body position has been recognized as a possible postural factor leading to BP dysregulation. We conducted a cross-sectional study to investigate the BP response to a change in body position from supine to prone. The study subjects consisted of 271 middle-aged healthy males, randomly selected from the employees of a large manufacturing enterprise in Ehime Prefecture, Japan. Brachial BP and heart rate were measured in a sitting, supine and prone position, in that order, and each difference was defined as a postural change. The postural changes in aortic hemodynamics were also assessed using a SphygmoCor system. The basal BP measured in the sitting position was significantly decreased in the supine position (132+/-18 to 130+/-17 mmHg, p<0.001). A further reduction was observed after the postural change from supine to prone (130+/-17 to 125+/-16 mmHg, p<0.001). The heart rate was increased with the supine-to-prone postural change (4.1+/-5.8 beats/min, p<0.001), while it showed a significant decrease with the sitting-to-supine postural change (-7.6+/-5.6 beats/ min, p<0.05). The impact of BP reduction was more prominent in the aortic artery (-3.3+/-6.7%) than the brachial artery (-3.0+/-6.3%, p=0.020). Multiple regression analysis showed that basal systolic BP was a solely significant determinant of the prone-hypotension (beta=-0.309, p<0.001). In conclusion, these results indicate that lying in a prone posture could lead to unregulated postural hypotension, which has the possibility of being a novel predictor of cardiovascular frailty.

Adult↗

PubMed1998

Usefulness of the non-distension of the stomach in the evaluation of perigastric invasion in advanced gastric cancer by CT.

The purpose of this study was to evaluate by CT the usefulness of the non-distension of the stomach in determining invasion of the gastric cancer into perigastric space and adjacent organs. Forty-eight patients with pathologically proved gastric cancer were studied by conventional CT. Patients were examined using two techniques: (a) non-distension of the stomach in the supine position and 34 patients additionally in prone position; and (b) distension of the stomach with water or air in the supine and/or prone position. CT findings by both techniques were separately analysed preoperatively and compared to surgical findings. Invasion of perigastric fat was better demonstrated by the non-distension technique in 15 of the 36 patients with pathologically proven fat infiltration. Non-distension technique was more accurate than distension in detecting: (a) involvement of gastric ligaments (80 versus 67% for gastrohepatic, 85 versus 73% for gastrocolic and 80% by both techniques for gastrosplenic ligament); (b) perigastric lymphadenopathy (86% by both techniques for lymph nodes sited at the gastrohepatic ligament, 85 versus 75% for gastrocolic and 85 versus 80% for gastrosplenic ligament lymph nodes, respectively); and (c) pancreatic invasion (86 versus 80%). The prone position with non-distended stomach was particularly helpful in excluding pancreatic invasion in five patients with carcinoma of the gastric body. The distension technique was more accurate in demonstrating perigastric extension in gastroesophageal junction tumors in two patients. In conclusion, additional CT of the non-distended stomach with the patient in prone position can provide further evidence about infiltration of the perigastric fat, ligaments, lymph nodes and pancreas, in patients with gastric carcinoma, with the exception of gastroesophageal junction tumors.

Adenocarcinoma↗

PubMed2002

Gas exchange in the ventilated patient.

Increased knowledge of the pathophysiologic mechanisms of impaired gas exchange during acute respiratory failure during recent years has stimulated many studies that evaluate different treatments to improve oxygenation and outcome. Changes in body position (mainly prone positioning) can significantly improve gas exchange in patients with acute respiratory distress syndrome and acute lung failure, with few complications related to the maneuver; however, no survival advantage has yet been detected. A correlation between aerated lung tissue and oxygenation also confirms the importance of recruitment maneuvers in improving gas exchange. Recent suggestions that recruitment of alveoli proceeds during most of the inspired vital capacity and not only around the lower inflection point of the pressure-volume curve raises the question how to best perform recruitment maneuvers. New data support the hypothesis that maintenance of even small amount of spontaneous breathing during mechanical ventilation (with airway pressure release ventilation or biphasic positive airway pressure) can improve gas exchange, whereas other unconventional ventilatory modes have not yet proved advantageous. Some mechanisms responsible for the high percentage of nonresponse to inhaled nitric oxide have recently been proposed, and combinations of inhaled nitric oxide with other therapies have been tested. Increased knowledge in this area may, in the future, make inhaled nitric oxide more attractive in the treatment of adult respiratory failure as well as in neonatal intensive care.

Humans↗

PubMed2000

The effects of body positioning on sucking behaviour in sick neonates.

UNLABELLED: Some infants show better oxygenation in the prone position compared to the supine position while they are bottle-fed; however, the reason for this phenomenon is not clear. The purpose of this study was to obtain a better understanding of the effects of body position on the oral feeding performance, i.e. the sucking pressure, frequency, efficiency, and ventilation. A total of 14 infants (12 full-term, 2 preterm), who often showed O2 desaturation (SpO2 < 90) during oral feeding, were enrolled in the study. The infants were fed either in the supine position or in the prone position throughout feeding. Oxygen saturation was recorded with a pulse oxymeter. The sucking pressure was measured with a 1 mm I.D. silicone tube inserted into the artificial nipple. The ventilation volume during bottle feeding was measured with a pneumotachograph. The prone position resulted in better oxygenation (97.2 +/- 0.6% prone, 92.5 +/- 0.9% supine, P < 0.05) and larger tidal volume (6.4 +/- 0.8 ml/kg prone and 4.9 +/- 0.6 ml/kg supine, P < 0.05), although the minute ventilation during bottle-feeding was not different from that in the supine position. In the prone position, the sucking pressure and frequency were higher and the duration of each suck was shorter. CONCLUSION: Sucking in the prone position may to some extent reduce disadvantages of oral feeding on ventilation.

Gestational Age↗

PubMed2002

Interaction between apnea, prone sleep position and gliosis in the brainstems of victims of SIDS.

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died suddenly and unexpectedly under 6 months of age. Of these, 26 died from sudden infant death syndrome (SIDS), 5 from congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 from a prolonged seizure, 1 from prolonged neonatal hypoxemia, and 1 from meningitis and brain infarction. The frequency and duration of apneas recorded some 3-12 weeks prior to the infants' death were analyzed. The brainstem materials were collected and studied in an attempt to elucidate the relationship between sleep apnea, and prone sleep position and gliosis in some nuclei associated with cardiorespiratory characteristics, such as nucleus ambiguus in the medulla oblongata and the solitary nucleus, as well as structures associated with arousal phenomenon, such as the reticular formation, the superior central nucleus and the nucleus raphe magnus in the pons, the dorsal raphe nuclei in the midbrain and medulla oblongata, periaqueductal gray matter in midbrain, and locus ceruleus. Gliosis was estimated as the density of glial fibrillary acidic protein (GFAP)-positive reactive astrocytes. Variant-covariant analyses were carried out using the characteristics of apnea as an independent variable and sleep position and gliosis as dependent variables. A significant association was found only in the frequency of obstructive apnea and prone position (P<0.001) and gliosis in the raphe nuclei in the midbrain (P<0.001). Although prone position is a well-known risk factor for SIDS, the frequency of obstructive apnea has not been associated with the prone sleep position. The observed relation between prone sleep and the density of gliosis does not relate to epidemiological findings. Further studies are needed to investigate the unexpected statistical association.

Analysis of Variance↗