SEARCH · PubMed Health

Results for “Prone Position”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources

PubMed1997

Behaviour and physiological responses during prone and supine sleep in early infancy.

AIMS: To study the effect of prone and supine sleep on infant behaviour, peripheral skin temperature, and cardiorespiratory parameters to aid understanding of why prone sleeping is associated with an increased risk of sudden infant death syndrome. METHODS: Of 33 enrolled infants, 32 were studied at 2.5 and 28 at 5 months of age. A computer aided multichannel system was used for polysomnographic recordings. Behaviour was charted separately. RESULTS: Prone REM (active) sleep was associated with lower frequencies of short arousals, body movements and sighs, and a shorter duration of apnoeas than supine REM sleep at both ages. At 2.5 months there were less frequent episodes of periodic breathing during prone sleep in non-REM (quiet) and REM sleep. Heart rate and peripheral skin temperature were higher in the prone position during both sleep states at both ages. CONCLUSIONS: The observation of decreased variation in behaviour and respiratory pattern, increased heart rate, and increased peripheral skin temperature during prone compared with supine sleep may indicate that young infants are less able to maintain adequate respiratory and metabolic homoeostasis during prone sleep.

Female↗

PubMed1993

Inbuilt obsolescence in conventionally piloted advanced fighter aircraft.

If pilot and fighter plane capability to sustain accelerations in the 10 to 15 G range for many seconds or minutes provides an important tactical advantage, as some fighter pilots believe, currently used anti-G procedures, including the Combat Edge Technology (29), will provide only partial, questionably safe protection. Therefore, relative to preservation of maximal pilot effectiveness, current and future advanced fighters, if flown in seated positions, are physiologically outdated in respect to blackout and G-LOC prevention. Consequently, future victories in the air may come to the adversary first to discard conventional upright or partially supinated seats in favor of a biomedically advanced fighter, developed for flight in the fully horizontal, preferably prone, position.

Acceleration↗

PubMed2003

Effect of posture on oxygenation, lung volume, and respiratory mechanics in premature infants studied before discharge.

OBJECTIVES: To determine if the prone versus the supine posture was associated with higher oxygenation levels in prematurely born infants before discharge, whether any such effect was explained by alterations in lung volume or respiratory mechanics, and if the changes were greater in oxygen-dependent infants. PATIENTS: Twenty infants (10 oxygen-dependent), median gestational age 30 (range: 27-32) weeks, were studied at a median postconceptional age of 35 weeks (range: 32-38 weeks). METHODS: On 2 successive days, infants were studied both supine and prone; each posture was maintained for 3 hours. Oxygen saturation was continuously monitored and at the end of each 3-hour period; compliance and resistance of the respiratory system and functional residual capacity (FRC) were measured. RESULTS: Overall, the median oxygen saturation and FRC were significantly higher in the prone position; compliance of the respiratory system and resistance of the respiratory system were not significantly affected by posture. Differences in oxygen saturation and FRC were significantly higher in the prone posture in the oxygen-dependent, but not the nonoxygen-dependent infants. CONCLUSIONS: Superior oxygenation in the prone posture in oxygen-dependent premature infants studied before discharge could be explained by higher lung volumes.

Functional Residual Capacity↗

PubMed1993

Inhibition of the soleus H-reflex in standing man.

There exists evidence to support the notion that the segmental reflex system is not fixed and inflexible, but rather is highly modifiable under a variety of circumstances. In this study the H-wave and M-wave recruitment curves were obtained from 19 subjects, utilizing the procedures outlined by Hugon. Each subject was tested on one day under two randomly administered conditions: (1) standing; and (2) prone. Once in place, the recording and stimulating electrodes were not removed until the completion of the study, to ensure that exact placement was maintained. A percutaneous electrical stimulus (1 ms pulse) was utilized to elicit the pulse. The current was monitored with a current probe, and was increased in 2 mA increments from zero until a maximal M-wave was obtained. An analysis of variance revealed significant increases in the amplitude of the H-wave (P < 0.05) when the subject was prone with no significant increases in the M-wave. The results indicate significantly higher H/M ratios with the subjects in the prone position. Therefore, it is concluded that H-reflex amplitude is tonically depressed when the subject is maintaining a standing position.

Adult↗

PubMed2003

Intravitreal gas for submacular haemorrhage.

Submacular haemorrhage is an important cause for sudden visual loss needing immediate intervention. We report a case of submacular haemorrhage causing profound visual loss, which resolved after intravitreal injection of perfluoropropane (C3F8) gas followed by strict prone positioning.

Female↗

PubMed1995

A finite element analysis of the effects of the abdomen on regional lung expansion.

A finite element model of the dog lung, heart and abdomen, consisting of three solid linearly elastic bodies, was developed to study the effects of gravity on the vertical stress distribution and lung volume in different body positions at functional residual capacity (FRC). The geometry of the lung was obtained from an isolated dried dog lung after inflation to total lung capacity (TLC). The compliance of the rib cage, diaphragm and the abdomen was simulated by spring elements located on their surfaces. In the prone position, gravitational forces acting only on the lung contributed to the vertical gradient (0.19 cmH2O/cm) in transpulmonary pressure (Ptp). This result was independent of chest wall compliance. In the supine position, the addition of the heart and abdomen with a compliant diaphragm and abdominal walls increased the vertical Ptp gradient to 0.53 cmH2O/cm. In the head-up (upright) position, both heart and abdominal weight contributed to the vertical gradient (0.47 cmH2O/cm). Diaphragmatic compliance was of less importance to the vertical gradient in the head-up and head-down positions in the absence of the abdomen. The smallest vertical gradient (0.11 cmH2O/cm) was obtained in the head-down position with abdominal weight reducing the gradient caused by lung weight. Lung volume at FRC was virtually unaffected by gravity in the prone body position, was reduced by gravity in the supine and head-down positions but increased in the head-up position. The effects of a compliant diaphragm and abdominal weight are important contributors to the distribution of stress and volume in the intact lung.

Abdomen↗

PubMed1990

Blood loss, operating time, and positioning of the patient in lumbar disc surgery.

Many textbooks and papers on lumbar disc surgery still, nearly 40 years after the first description of a variant of the kneeling position, pay no attention to the positioning of the patient. In this study, the association between intraoperative blood loss, operating time, and position of the patient was studied in 436 patients undergoing a standard macrosurgical operation for lumbar disc herniation. Prone position on bolsters was used in 216 cases, 192 of which were primary operations, and a frame-supported kneeling position in 220, 203 of which were primary operations. The mean blood losses in prone versus kneeling positions in the primary operations were 376 ml and 150 ml, respectively (P less than 0.001), and the mean operating times were 74 minutes and 52 minutes, respectively (P less than 0.001). The 99% confidence interval for the difference between the mean operating times was from 15 to 29 minutes. A moderate nonlinear positive correlation was found between intraoperative blood loss and operating time. No intraoperative complications attributable to the position of the patient emerged. On the basis of the findings in this study, the use of kneeling position is strongly advocated.

Adult↗

PubMed2002

Does a pelvic belt influence sacroiliac joint laxity?

OBJECTIVE: To evaluate the influence of different positions and tensions of a pelvic belt on sacroiliac joint laxity in healthy young women. BACKGROUND: Clinical experience has shown that positive effects can be obtained with different positions and tensions of a pelvic belt. A functional approach to the treatment of the unstable pelvic girdle requires an understanding of the effect of a pelvic belt on a normal pelvic girdle. METHODS: Sacroiliac joint laxity was assessed with Doppler imaging of vibrations. The influence of two different positions (low: at the level of the symphysis and high: just below the anterior superior iliac spines) and tensions (50 and 100 N) of a pelvic belt was measured in ten healthy subjects, in the prone position. Data were analysed using repeated measures analysis of variance. RESULTS: Tension does not have a significant influence on the amount by which sacroiliac joint laxity with belt differs from sacroiliac joint laxity without belt. A significant effect was found for the position of the pelvic belt. Mean sacroiliac joint laxity value was 2.2 (SD, 0.2) threshold units nearer to the without-belt values when the belt was applied in low position as compared to the case with the belt in high position. CONCLUSIONS: A pelvic belt is most effective in a high position, while a tension of 100 N does not reduce laxity more than 50 N. RELEVANCE: Information about the biomechanical effects of a pelvic belt provided by this study will contribute to a better understanding of the treatment of women with pregnancy-related pelvic pain.

Adolescent↗

PubMed1995

[Transient tracheal obstruction during surgical correction of scoliosis in a patient with Marfan's syndrome].

A 13-yr-old male with Marfan's syndrome underwent surgical correction of severe scoliosis. He had not manifested dyspnea previously in any position. Under anesthesia with thiamylal and vecuronium, his trachea was intubated with a reinforced endotracheal tube without any difficulty. Anesthesia was maintained with nitrous oxide and fentanyl, 8 micrograms.kg-1. The patient was placed in a prone position. Thirty min after the start of operation, when orthopedists compressed the thoracic vertebrae vertically, positive pressure ventilation became impossible abruptly, even with a high airway pressure. Three min later, ventilation became possible after cessation of compression and by mouth-to-tube insufflation. SpO2 monitored with a pulse oximeter recovered immediately from 61% to 99%. A capnogram showed a lengthy retardation of an inspiratory phase. Emergency fibreoptic bronchoscopy revealed that the trachea had been compressed vertically; the compression was reduced by moving the chest supporters laterally. After the apneic episode, the operation continued uneventfully, and he was discharged a month later. A severe deformity of the thorax due to severe scoliosis and weak tracheal tissue due to connective tissue defect caused partial tracheal compression before the surgery, and made his trachea susceptible to complete obstruction by vertical external compression on the thorax. Patients with Marfan's syndrome and scoliosis should have careful preoperative airway evaluation. The selection and positioning of endotracheal tubes should be done with care. During surgery, the patient's body position and the condition of the trachea should be checked frequently. Capnography and fiberoptic bronchoscopy seem to be mandatory for early detection of tracheal stenosis and prevention of tracheal obstruction.

Adolescent↗

PubMedDate not supplied

Turning a patient prone with ARDS.

This case report outlines the treatment and management of a patient who developed ARDS. The causes of ARDS and disordered physiology are discussed briefly. Prone positioning is identified as an important component of management.

Adolescent↗

PubMed2003

Observation of idiopathic full-thickness macular hole closure in early postoperative period as evaluated by optical coherence tomography.

PURPOSE: To report the optical coherence tomography (OCT)-determined progressive changes in a macular hole (MH) following vitreous surgery with a gas tamponade. Observational case report. METHODS: A 60-year-old woman with an idiopathic full-thickness MH (Gass, Stage 2) in the left eye underwent vitreous surgery with a gas tamponade. The progressive closure of the MH was followed by OCT because an unplanned decrease of the gas tamponade made the macula accessible to OCT examination. RESULTS: On day 1, the tissue surrounding the MH extended into the center, and on day 2, the subretinal fluid and foveal cysts decreased and the retinal separation was reduced. On the third postoperative day, the MH was closed and the foveal contour was similar to that of normal retinas. CONCLUSION: These results demonstrated that a small MH appears to be closed by 3 days after vitrectomy with gas tamponade. Although we cannot generalize to all sizes of MH, our findings suggest that small MHs are closed much earlier than reported and that the duration of maintaining a prone position can be shortened.

Diagnostic Techniques, Ophthalmological↗

PubMed1998

Use of high-frequency and nonconventional ventilation for respiratory failure.

Over the past several years, many new strategies have evolved for improving the care of patients with acute lung injury and respiratory failure. Although many of these new modalities remain unproven, some show much promise for decreasing the morbidity and mortality seen in critically ill patients who need assisted ventilation. In this review, we discuss recent data concerning four of these modalities: high frequency ventilation, prone positioning, tracheal gas insufflation, and partial liquid ventilation.

Critical Care↗

PubMed1998

Softness and potential to cause rebreathing: Differences in bedding used by infants at high and low risk for sudden infant death syndrome.

OBJECTIVE: This study was carried out to determine whether bedding used by infants, who are at either high or low risk for sudden infant death syndrome (SIDS), differs in physical properties favoring rebreathing of exhaled gases. STUDY DESIGN: We compared softness and limitation of carbon dioxide dispersal by bedding, using a mechanical model. A questionnaire was used to describe sociodemographic risk factors and sleep practices; bedding was studied in homes with a model positioned where each infant was found sleeping that morning. RESULTS: The groups differed with respect to five sociodemographic risk factors (p values all < or = 0.0001). In addition, infants at higher risk were more likely to have been placed to sleep prone (46%, p = 0.02) by parents who were less likely to be aware of the risk associated with the prone position (62% aware, p = 0.005). Infants at higher risk had softer bedding (p < 0.0001, 54.1+/-17.2 cm2 vs 33.7+/-7.7 cm2 in contact with model), which caused more limitation of carbon dioxide dispersal (p = 0.008; CO2 retained, 0.60%+/-0.15% vs 0.34%+/-0.05%). CONCLUSIONS: A series of infants who are at high risk for SIDS because of sociodemographic factors more often sleep on bedding that has physical properties favoring rebreathing, and their parents are less often aware of the risk associated with prone sleeping.

Bedding and Linens↗

PubMedDate not supplied

Bilateral ulnar decubitus as a complication of macular hole surgery.

Bilateral ulnar decubitus is described in a 69-year-old patient maintaining prone positioning after vitrectomy, membrane peeling, and perfluoropropane gas injection for the treatment of a macular hole. Patients should be warned to report any skin breakdown or ulnar paresthesias resulting from positioning and to change position frequently to allow weight bearing on other parts of the body. Patients with certain personality traits may be more likely to maintain correct positioning despite pain or injury to ensure surgical success.

Aged↗

PubMed2002

A randomized trial on the effects of body positions on lung function with acute respiratory failure patients.

In a randomized controlled trial, we compared the potential benefits of position changes on arterial oxygen pressure in 32 patients with acute respiratory failure, maintained on artificial ventilators, distinguishing prominently as left-sided, right-sided or bilateral lung disease. Our results indicate that randomly alternating supine, left-lateral, right-lateral and prone positions have influence on gas exchange and that improvement of arterial oxygen pressure is associated with various positions. Our results show, therefore, that nursing care of patients on artificial ventilators involving changes in body positions (a simple and noninvasive means of assistance) has important therapeutic consequences and warrants attention in clinical practice.

Acute Disease↗

PubMed2006

Tragedy, utopia and medical progress.

In this article, tragedy and utopia are juxtaposed, and it is proposed that the problem of "medicalisation" is better understood in a framework of tragedy than in a utopian one. In utopia, it is presupposed that there is an error behind every setback and every side effect, whereas tragedy brings to light how side effects can be the result of irreconcilable conflicts. Medicalisation is to some extent the result of such a tragic conflict. We are given power by medical progress, but are also confronted with our fallibility, thus provoking insecurity. This situation is illustrated by the sudden infant death syndrome (SIDS). Recent epidemiological investigations have shown that infants sleeping in a prone position have a 15-20 times higher risk of dying from SIDS than infants sleeping in a supine position. A simple means of preventing infant death is suggested by this discovery, but insecurity is also created. What else has been overlooked? Perhaps a draught, or wet diapers, or clothes of wool are just as dangerous as sleeping prone? Further investigations and precautions will be needed, but medicalisation prevails.

Attitude of Health Personnel↗

PubMed1999

The usefulness of glucagon hydrochloride for colonic distention in CT colonography.

OBJECTIVE: The purpose of this study was to compare colonic distention with and without glucagon hydrochloride during CT colonography. SUBJECTS AND METHODS: CT colonography using single breath-hold, thin-section helical technique was performed on 60 patients who were in the supine and prone positions. Magnesium citrate and polyethylene glycol were used for bowel preparation. Colonic air insufflation averaged 30 bulb compressions. Thirty-three patients received IV glucagon (1 mg), and 27 patients did not. The colon was divided into eight segments, and the adequacy of the distention of each segment was evaluated. Overall colonic distention scores, defined as the number of inadequately distended segments (0-8), were recorded for the supine, prone, and combined positions. In the combined position, inadequate distention was defined as identical segments that were inadequately distended in both positions. RESULTS: A total of 960 segments were evaluated: 528 segments in the glucagon group and 432 segments in the nonglucagon group. In the glucagon group, 444 segments (84.1%) were adequately distended. In the nonglucagon group, 365 segments (84.5%) were adequately distended. The median and range for overall colonic distention scores in the supine, prone, and combined positions were 1 (0-3), 1 (0-3), and 0 (0), respectively, for the glucagon group and 1 (0-6), 1 (0-6), and 0 (0-1), respectively, for the nonglucagon group. We found no statistically significant difference in overall colonic distention between the glucagon group and the nonglucagon group for the supine (p = .84), prone (p = .15), or combined (p = .28) positions. CONCLUSION: Glucagon administration before CT colonography does not improve colonic distention.

Adult↗

PubMed2004

Distributions of lung ventilation and perfusion in prone and supine humans exposed to hypergravity.

When normal subjects are exposed to hypergravity [5 times normal gravity (5 G)] there is an impaired arterial oxygenation that is less severe in the prone compared with supine posture. We hypothesized that under these conditions the heterogeneities of ventilation and/or perfusion distributions would be less prominent when subjects were prone compared with supine. Expirograms from a combined rebreathing-single breath washout maneuver (Rohdin M, Sundblad P, and Linnarsson D. J Appl Physiol 96: 1470-1477, 2004) were analyzed for vital capacity (VC), phase III slope, and phase IV amplitude, to analyze heterogeneities in ventilation (Ar) and perfusion [CO(2)-to-Ar ratio (CO(2)/Ar)] distribution, respectively. During hypergravity, VC decreased more in the supine than in the prone position (ANOVA, P = 0.02). Phase III slope was more positive for Ar (P = 0.003) and more negative for CO(2)/Ar (P = 0.007) in the supine compared with prone posture at 5 G, in agreement with the notion of a more severe hypergravity-induced ventilation-perfusion mismatch in supine posture. Phase IV amplitude became lower in the supine than in the prone posture for both Ar (P = 0.02) and CO(2)/Ar (P = 0.004) during hypergravity as a result of the more reduced VC in the supine posture. We speculate that results of VC and phase IV amplitude are due to the differences in heart-lung interaction and diaphragm position between postures: a stable position of the heart and diaphragm in prone hypergravity, in contrast to supine in which the weight of the heart and a cephalad shift of the diaphragm compress lung tissue.

Adult↗