PubMed Health⌕ Search

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 307 records · Page 17Linked to original sources
PubMed2001

The effect of prone positioning on intraocular pressure in anesthetized patients.

BACKGROUND: Ocular perfusion pressure is commonly defined as mean arterial pressure minus intraocular pressure (IOP). Changes in mean arterial pressure or IOP can affect ocular perfusion pressure. IOP has not been studied in this context in the prone anesthetized patient. METHODS: After institutional human studies committee approval and informed consent, 20 patients (American Society of Anesthesiologists physical status I-III) without eye disease who were scheduled for spine surgery in the prone position were enrolled. IOP was measured with a Tono-pen XL handheld tonometer at five time points: awake supine (baseline), anesthetized (supine 1), anesthetized prone (prone 1), anesthetized prone at conclusion of case (prone 2), and anesthetized supine before wake-up (supine 2). Anesthetic protocol was standardized. The head was positioned with a pinned head-holder. Data were analyzed with repeated-measures analysis of variance and paired t test. RESULTS: Supine 1 IOP (13 +/- 1 mmHg) decreased from baseline (19 +/- 1 mmHg) (P < 0.05). Prone 1 IOP (27 +/- 2 mmHg) increased in comparison with baseline (P < 0.05) and supine 1 (P < 0.05). Prone 2 IOP (40 +/- 2 mmHg) was measured after 320 +/- 107 min in the prone position and was significantly increased in comparison with all previous measurements (P < 0.05). Supine 2 IOP (31 +/- 2 mmHg) decreased in comparison with prone 2 IOP (P < 0.05) but was relatively elevated in comparison with supine 1 and baseline (P < 0.05). Hemodynamic and ventilatory parameters remained unchanged during the prone period. CONCLUSIONS: Prone positioning increases IOP during anesthesia. Ocular perfusion pressure could therefore decrease, despite maintenance of normotension.

Adolescent↗
PubMed1995

Cardiac arrest and resuscitation of a 6-month old achondroplastic baby undergoing neurosurgery in the prone position.

We describe the case of a 6-month-old achondroplastic baby who underwent foramen magnum decompression to relieve congenital cervical cord compression. During the procedure, acute hypotension occurred secondary to cord compression, and following attempts to alleviate this, torrential haemorrhage ensued and air was entrained into the circulation through large venous channels in the surgical field. This resulted in an asystolic cardiac arrest from which the baby was resuscitated whilst remaining in the prone position. Haemorrhage remained difficult to control and a second episode of air embolism occurred 5 min later leading to a profound bradycardia and hypotension again requiring full cardiorespiratory resuscitation in the prone position. In total, 11 min elapsed before an adequate spontaneous cardiac output was re-established. The procedure was abandoned and the patient transferred to the intensive care unit for postoperative management. An electroencephalogram performed after 24 h was reported as normal, and clinically the child made a full neurological recovery.

Achondroplasia↗
PubMed1988

Extracorporeal shock wave lithotripsy in the prone position: treatment of stones in the distal ureter or anomalous kidney.

A total of 15 patients underwent ESWL using the Dornier HM3 lithotriptor with the patient in the prone position. The stones were in the distal ureter over the sacroiliac joint in 10 patients, 8 of whom had undergone unsuccessful ureteroscopic manipulation. Two patients had horseshoe kidneys with stones that were too anterior to permit accurate targeting with the patient in the standard supine position. One patient had a solitary stone in a pelvic kidney and 1 had an obstructing ureteropelvic junction stone in a crossed ectopic kidney. The final patient had a reconstructed lower urinary tract with a stone at 1 of the ureterointestinal anastomoses. Excellent pulverization was achieved in all patients after only 1 prone ESWL treatment. One patient required temporary percutaneous nephrostomy after ESWL and 1 may require retrograde manipulation of fragments at the ureterovesical junction. No patient had melena, and other than temporary ileus in 1 patient who had concurrent supine ESWL of renal calculi, no gastrointestinal complications were seen. All but 1 patient were free of stones 1 month after prone ESWL. Prone ESWL prevents blockage of shock wave energy by the bony pelvis, because the shock waves enter anteriorly and exit posteriorly. ESWL with the patient in the prone position is a safe and effective treatment of calculi in the distal ureter or anomalous kidney.

Adult↗
PubMed1987

Importance of prone-position film during intravenous urography in detection of bladder tumors.

Three patients with neoplasms on the anterior wall or dome of the urinary bladder underwent intravenous urography (IVU). In each case, the lesion was detected only on the prone-position radiograph. Contrast medium layers in the dependent part of the bladder. If all filming is performed with the patient in supine position, lesions on the anterior wall may be undetected. We advocate routine inclusion of one prone-position film during IVU.

Adenocarcinoma↗
PubMed1986

[Significance of the Bárány convection hypothesis for thermal nystagmus. Quantitative comparison of the intensity of thermal nystagmus in supine and prone position].

The hypothesis of Bárány explaining thermic nystagmus has been shaken. We must accept a non-convective triggering of nystagmus in extraterrestrial space. Under terrestrial conditions, however, the reversibility of the thermic nystagmus by changing from supine to prone position continues to support the convection hypothesis. We examined the nystagmus intensity in the supine and prone position with 22 healthy ears. The thermic stimulus was monitored via computer-controlled alternating irrigation system. The sequence of examinations was randomised and the evaluation of the nystagmus effected by automatic analysis. Our data allow to assess the importance of the non-convective nystagmus. With clinical test conditions about 85% of the maximal thermal reaction can be explained by the convection hypothesis of Bárány. However, interindividual variance is considerable, and one exceptional case with predominantly non-convectively released nystagmus is presented.

Adult↗
PubMedDate not supplied

Comparison of post-stress ejection fraction and relative left ventricular volumes by automatic analysis of gated myocardial perfusion single-photon emission computed tomography acquired in the supine and prone positions.

BACKGROUND: We have previously described an automatic method for measuring left ventricular ejection fraction (LVEF) for myocardial perfusion single-photon emission computed tomography (SPECT). The repeatability of this method has not been previously described. METHODS AND RESULTS: This study compares LVEF and relative end-systolic and end-diastolic volumes assessed from myocardial perfusion SPECT by our automatic method in 180 consecutive patients undergoing gated myocardial perfusion SPECT with injection of 99mTc-labeled sestamibi in whom the acquisitions were performed sequentially in supine and prone positions. The algorithm operated completely automatically in the prone and supine positions in 178 of the 180 patients. Very high correlations were observed for LVEF (r = 0.93), relative left ventricular end-systolic volume (r = 0.98), and relative left ventricular end-diastolic volume (r = 0.97). The mean paired absolute difference between LVEFs in the prone and supine position was 3.8+/-3.2, for left ventricular end-systolic volume was 4.9+/-4.8 ml, and for left ventricular end-diastolic volume was 7.4+/-6.7 ml. When patients were classified by the extent and severity of stress perfusion defect, there was no significant difference in repeatability for the measurements in any category. CONCLUSIONS: Our algorithm for automatic quantification of LVEF and relative end-systolic and end-diastolic volumes from gated 99mTc sestamibi myocardial perfusion SPECT is repeatable. When performed in the prone position, values of ejection fractions and ventricular volumes are essentially identical to those obtained in the supine position.

Adult↗
PubMed1992

New head-prone position for posterior fossa surgery in infants with severe hydrocephalus.

A new head-prone position is described for posterior cranial fossa surgery on infants whose cerebral cortical mantle has been markedly thinned by severe hydrocephalus. The new position furnished a direct line of sight to the apex of the IV ventricle corresponding to that provided by the classic high sitting position, without the latter's risks of air embolism and of acute subdural hematoma secondary to tearing of corticodural bridging vessels due to escape of gravity-impelled CSF from the large ventricles. The anesthesiologic technique, the positioning of the patient, and the surgeon's posture presented no unusual problems.

Anesthesia, Inhalation↗
PubMed2006

Contact pressure distribution features in Down syndrome infants in supine and prone positions, analyzed by photoelastic methods.

BACKGROUND: Local force distribution supporting the bodyweight of infants with Down syndrome (DS) appears to be different from that of healthy controls. The purpose of the present study was to establish methods to assess this force distribution and to allow therapeutic evaluation of neurological development in DS infants prior to walking. METHODS: Contact pressure distribution patterns in supine and prone positions were measured by photoelastic methods and were compared between DS infants and healthy controls. The DS group included eight subjects, seven with regular trisomy 21, and one with a Robertson translocation. The controls consisted of 14 neonates, four 4-month-old infants and eight 7-month-old infants. RESULTS: In both groups, head loading ratio decreased as age advanced but the decrement was less in the test group than in the control group. When the bodyweight loading ratios were measured in two different lying positions, that is, prone and supine, the ratios for prone generally tended to be smaller than those for supine in the controls. This kind of difference between prone and supine was not seen in the DS group. The bodyweight is somewhat sustained with limbs and the limbs loading ratios in the DS group were always significantly lower than in the controls. CONCLUSION: Coordinated development of weight-supporting limbs seems to be poor in the DS group.

Age Factors↗
PubMed2001

4A randomized trial of prolonged prone positioning in children with acute respiratory failure.

STUDY OBJECTIVE: To compare the effect of the prone position (PP) vs supine position (SP) on oxygenation in children with acute respiratory failure (ARF). DESIGN: Prospective, randomized controlled trial. SETTING: A 36-bed pediatric critical-care unit in a tertiary-care, university-based children's hospital. PATIENTS: Ten children (mean [SD] age, 5 +/- 3.6 years) with ARF with a baseline oxygenation index (OI) of 22 +/- 8.5. INTERVENTIONS: Following a period of stabilization in the SP, baseline data were collected and patients were randomized to one of two groups in a two-crossover study design: group 1, supine/prone sequence; group 2, prone/supine sequence. Each position was maintained for 12 h. Lung mechanics and acute response to inhaled nitric oxide were examined in each position. MEASUREMENTS AND MAIN RESULTS: OI was significantly better in the PP compared to the SP over the 12-h period (analysis of variance, p = 0.0016). When patients were prone, a significant improvement in OI was detected (7.9 +/- 5.3; p = 0.002); this improvement occurred early (within 2 h in 9 of 10 patients) and was sustained over the 12-h study period. Static respiratory system compliance and resistance were not significantly affected by the position change. Inhaled nitric oxide had no effect on oxygenation in either position. Urine output increased while prone, resulting in a significantly improved fluid balance (+ 6.6 +/- 15.2 mL/kg/12 h in PP vs + 18.9 +/- 13.6 mL/kg/12 h in SP; p = 0.041). No serious adverse effects were detected in the PP. CONCLUSION: In children with ARF, oxygenation is significantly superior in the PP than in the SP. This improvement occurs early, remains sustained for a 12-h period, and is independent of changes in lung mechanics.

Acute Disease↗
PubMed1984

[Prone position in hysterosalpingography].

The authors discuss the importance of prone hysterosalpingography to the aim of a careful tubal examination. Nearly all the complete or partial tubal obstructions, observed during supine hysterosalpingography, have been resolved by the simple prone position. The high percentage (91%) of successes, without pharmacological help, recommends the routine use of this simple method in all cases of doubtful tubal obstructions.

Fallopian Tube Diseases↗
PubMed2001

Short-term effects of inhaled nitric oxide and prone position in pulmonary and extrapulmonary acute respiratory distress syndrome.

Inhaled nitric oxide (NO) and prone position (PP) are frequently used in the treatment of acute respiratory distress syndrome (ARDS). We compared the gas exchange and hemodynamic effects induced by the combination of NO inhalation and PP in patients with ARDS and analyzed whether or not pulmonary (Pu) and extrapulmonary (Epu) ARDS patients behave differently. Eight Pu and seven Epu ARDS patients were studied in four situations: supine position (SP); SP with NO inhalation at 5 ppm (SP + NO); PP; and PP with NO inhalation (PP + NO). In comparison with SP, NO inhalation and PP induced significant increases in Pa(O(2))/FI(O(2)) (from 106 +/- 58 in SP to 131 +/- 69 mm Hg in SP + NO, p = 0.01, and to 184 +/- 67 mm Hg in PP, p < 0.001). Pu and Epu ARDS showed a similar improvement in Pa(O(2))/FI(O2) with PP. Only Pu ARDS patients showed a significant increase (p < 0.001) in oxygenation induced by NO inhalation from 81 +/- 45 to 100 +/- 50 mm Hg in SP, and from 146 +/- 53 to 197 +/- 98 mm Hg in PP. In conclusion, PP is associated with a marked improvement in oxygenation, irrespective of the causes of ARDS, and additive effects of NO inhalation are mainly seen in patients with Pu ARDS.

Administration, Inhalation↗
PubMed2006

Cardiopulmonary resuscitation in prone position: a simplified method for outpatients.

BACKGROUND: The efficacy of cardiopulmonary resuscitation (CPR) is vital for saving lives of victims with sudden cardiac arrest. In 1960, Kuowenhoven and colleagues proposed the method that has become standard for CPR. Despite vast input of resources for public education and training of this procedure, its success rate outside hospitals remains poor to dismal. During CPR, restoration of respiration is as important as circulation. But opening the airway and giving effective mouth-to-mouth respiration is difficult for lay people to learn. Furthermore, most bystanders are reluctant to do mouth-to-mouth respiration because of the risk of infection. Therefore, the general population needs a more simplified CPR method for outpatients. The practice of CPR in the prone position, first proposed by McNeil in 1989, has not been adopted, despite the fact that it meets the desirable requirements of ideal resuscitation: simultaneous restoration of circulation and respiration with a very simple maneuver. METHODS: Part 1 (circulation test): Eleven patients who expired in the intensive care unit (ICU), with arterial lines attached, received standard pre-cordial cardiac massage, and the generated blood pressure (BP) was recorded. They were then turned to the prone position, with the head turned to one side. We compressed the patient's thoracic spine with the same force used in standard CPR (rhythm of approximately 60 per minute each time when the back bounces back), and the BP was also recorded. Part 2 (ventilation test): Ten healthy volunteers (5 doctors and 5 nurses) were enlisted for respiratory assessment during compression on the back. With the nose clipped and spontaneous breathing held, the volunteer's exhaled tidal volume upon compression was measured with a spirometer. RESULTS: Standard external cardiac massage of the cadavers generated BPs of 55 +/- 20/13 +/- 7 mmHg; however, external compression on the back of the cadavers generated higher BP of 79 +/- 20/17 +/- 10 mmHg (p = 0.028, Wilcoxon signed-rank analysis). External compression on the back of the volunteers generated mean tidal volumes of 399 +/- 110 mL. CONCLUSION: Our study revealed that prone CPR provides good respiratory and circulatory support at the same time. It is easy to perform and it may be a good alternative way for bystanders to perform CPR in public surroundings. We recommend that more investigators do further studies on this topic.

Adult↗
PubMed2006

[Evaluation of setup error and adequate setup margins in patients with prostate cancer treated by IMRT and fixed in the prone position using a set of immobilization devices].

PURPOSE: Positional reproducibility in patients with prostate cancer fixed in the prone position with a set of immobilization devices for external-beam intensity-modulated radiation therapy (IMRT) was evaluated. In addition, the adequacy of our positional error reduction strategy and current planning target volume (PTV) margins was also evaluated. RESULTS: Systematic error was corrected by the positional correction that we executed at the first stage of irradiation. The setup margin that we had calculated was 1.1 mm in the L-R direction, 1.3 mm in the A-P direction, and 2.7 mm in the C-C direction. CONCLUSION: We determined that the effectiveness of the method of correcting the error margin and the setup accuracy of the fixed method were well maintained.

Humans↗
PubMed2006

Effects of prone position on the oxygenation of patients with acute respiratory distress syndrome.

CONTEXT AND OBJECTIVE: Acute respiratory distress syndrome (ARDS) is characterized by arterial hypoxemia, and prone position (PP) is one possible management strategy. The objective here was to evaluate the effects of PP on oxygenation. DESIGN AND SETTING: Non-randomized, open, prospective, controlled clinical trial, in a surgical intensive care unit at a tertiary university hospital. METHODS: Forty-one ARDS patients underwent PP for three-hour periods. Arterial partial oxygen pressure (PaO2) was measured immediately before changing to PP, after 30, 60, 120 and 180 minutes in PP and 60 minutes after returning to dorsal recumbent position (DP). The paired-t and Dunnett tests were used. RESULTS: A notable clinical improvement in oxygenation (> 15%) was detected in 78.0% of patients. This persisted for 60 minutes after returning to DP in 56% and lasted for 12 and 48 hours in 53.6% and 46.3%, respectively. Maximum improvement was seen after 30 minutes in 12.5% of responding patients and after 180 minutes in 40.6%. No statistically significant associations between PP response and age, gender, weight, PEEP level, tidal volume, respiratory rate, PaO2/FiO2 or duration of mechanical ventilation were detected. One accidental extubation and four cases of deterioration through oxygenation were detected. The 48-hour mortality rate was 17%. CONCLUSIONS: For a significant number of ARDS patients, PP may rapidly enhance arterial oxygenation and its inclusion for management of severe ARDS is justified. However, it is not a cost-free maneuver and caution is needed in deciding on using PP.

Adolescent↗
PubMed2000

CT analysis of caliceal anatomy in the supine and prone positions.

PURPOSE: To assess the effect of patient positioning on the position of the kidneys and their consequent projection onto plain radiographs, thus ascertaining the need for special preoperative imaging. PATIENTS AND METHODS: Fourteen patients were studied by obtaining fine (5-mm)-cut contrast-enhanced CT scans in the pyelogram phase in both the supine and prone position. The orientation of the kidneys relative to the midsagittal plane of the body and the orientation of the anterior and posterior calices relative to the axis of the kidney were measured from hardcopy images. Comparison was made between prone and supine positions for left and right kidneys separately, as well as overall. RESULTS: The position of the patient had a small effect on the orientation of the kidneys, with the mean angle changing from 56.6 degrees when supine to 61.6 degrees when prone (p < 0.05). However, no significant change in caliceal orientation or the relative projection of the anterior and posterior calices occurred as a result. CONCLUSION: There is no need to carry out special preoperative imaging in the operative or prone position.

Adult↗
PubMed2001

The oxygenation variations related to prone positioning during mechanical ventilation: a clinical comparison between ARDS and non-ARDS hypoxemic patients.

OBJECTIVES: To compare, in clinical practice, the oxygenation variations related to prone positioning (PP) during mechanical ventilation in ARDS and non-ARDS hypoxemic patients. DESIGN AND SETTING: Prospective observational study of data on consecutive patients treated with the same protocol in the intensive care unit (ICU) of a university hospital. PATIENTS: From May 1996 to December 1998, 226 PP periods without adjunction of nitric oxide (NO) inhalation and/or almitrine bismesylate infusion, performed in 59 mechanically ventilated hypoxemic patients (arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) ratio <300 mmHg) with no evidence of left ventricular failure, were included in this study. MEASUREMENTS: Arterial blood gas was measured before the PP, at 1 h from the beginning of the PP, at the end of the PP and 1 h after returning to the supine position. RESULTS: We analyzed 136 PP periods in 34 non-ARDS patients (60.2%) and 90 in 25 ARDS patients. The PP was repeated and the duration of the PP periods was: 10.6+/-0.22 h. The PP during the mechanical ventilation appeared to be safe and well tolerated. A PaO2/FIO2 ratio improvement at the end of the PP period, occurred for 196 periods (86.7%) with a mean PaO2/FIO2 ratio increase of +46.4+/-0.03% at the end of the PP periods compared to the baseline supine value. The PaO2/FIO2 ratio variations at 1 h after the start of the PP, at the end of the PP period and at 1 h after the return to supine were not different in ARDS or non-ARDS hypoxemic patients. The PaO2/FIO2 ratio improvement appeared to be more intense and more rapid in ARDS patients. CONCLUSIONS: In about 90% of periods, PP improved the PaO2/FIO2 ratio in patients with ARDS as well as in hypoxemic patients with non-ARDS. Studies are necessary to determine the impact of PP on survival and the mechanical ventilation duration in ARDS or non-ARDS hypoxemic patients.

Analysis of Variance↗
PubMed1998

Efficacy of prone positioning during intravenous urography in patients with hematuria or urothelial tumor but no obstruction.

RATIONALE AND OBJECTIVES: The authors prospectively explored the efficacy of using prone positioning during intravenous urography to improve diagnostic visualization and eliminate the need for retrograde pyeloureterography in patients with no obstruction but with hematuria, history of urothelial tumor, or abnormal results of urine cytology. MATERIALS AND METHODS: Prone radiography was added to the usual intravenous urography protocol in 510 patients (347 men, 163 women) without urinary tract obstruction. Interpretations of intravenous urograms and recommendations for retrograde pyeloureterography were made before and after evaluation of the prone image. RESULTS: Confidence in the urographic interpretation was improved with acquisition of the prone radiograph in 100 of 510 patients (19.6%) (95% confidence interval, 82.1, 118). Retrograde pyeloureterography was obviated in 46 of 510 patients (9.0%) (95% confidence interval, 33.1, 58.9). The prone image was most helpful in evaluating the distal ureters (sacral and pelvic segments). CONCLUSION: Prone patient positioning during intravenous urography is useful when complete visualization of the upper urinary tract is desirable. Obtaining the additional image is cost-effective, even when only a few retrograde pyeloureterography studies are obviated.

Adult↗