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At least 1,153 records · Page 64Linked to original sources
PubMed2003

Use of prone ventilation in neurogenic pulmonary oedema.

We present a case of neurogenic pulmonary oedema (NPO) due to subarachnoid haemorrhage that resulted in hypoxia refractory to conventional mechanical ventilation. Prone positioning was employed, resulting in rapid and sustained improvement in oxygenation. We discuss the pathogenesis of NPO and the mechanism of action of prone ventilation. Prone ventilation may be of value in the management of NPO, both in treating life-threatening hypoxia and in optimizing neurological recovery. Further data are required on its effect on intracranial pressure after subarachnoid haemorrhage.

Adult↗
PubMed2001

Medullary cone movement in subjects with a normal spinal cord and in patients with a tethered spinal cord.

PURPOSE: To compare movement of the normal medullary cone when the patient has changed from a supine to prone position with that in patients with known or suspected tethered spinal cord syndrome. MATERIALS AND METHODS: Fifty-six individuals divided into three groups were examined with lumbar spine magnetic resonance (MR) imaging performed with the patient in the prone and supine positions. Group 1 consisted of 15 healthy volunteers and six patients with a herniated disk; group 2, 25 patients clinically suspected of having a tethered cord; and group 3, 10 patients who previously had undergone tethered cord surgery. RESULTS: All group 1 subjects showed distinct and statistically significant medullary cone movement (range, 21%--41%); no patient in group 3 showed movement (Wilcoxon rank sum test, P <.001). In group 2, the 20 patients in whom a definite diagnosis of tethered cord syndrome was made on the basis of initial supine MR image findings showed no movement, whereas two of five patients with normal supine MR images had abnormal and decreased cone movement at prone imaging. CONCLUSION: Prone MR imaging has no additional value when the supine MR image has clearly shown the cause of tethering or in patients who have undergone tethered cord surgery, but it can provide additional information in patients clinically suspected of having a tethered cord and in whom supine MR imaging depicted no abnormalities.

Adolescent↗
PubMed2000

Prone ventilation.

Considerable clinical experience confirms that oxygenation can be improved in many patients with ARDS by employing prone ventilation. The improvement occurs because, in the prone position, the lung fits into the thorax such that lung distention is more uniform and compressive forces extant in the supine position, which serve to cause dorsal airspace collapse, are reduced. Whether these changes translate into improved clinical outcomes has yet to be determined, but prone ventilation has the potential of reducing oxygen toxicity and limiting ventilator-induced lung injury.

Humans↗
PubMed1999

Piezoelectric shockwave lithotripsy of urinary calculi: comparative study of stone depth in kidney and ureter treatments.

PURPOSE: The aim of this prospective study was to assess the relation between stone depth and the efficiency of piezoelectric extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: A total of 150 patients presenting with 25 pelvic, 75 caliceal, and 25 upper and 25 lower ureteral calculi were treated using the EDAP LT02 lithotripter. All of the stones were easy to localize with sonographic and radiographic systems, and their largest diameter ranged from 4 to 25 mm (mean 8.5 mm). Renal and upper ureteral calculi were treated with the patient in the supine position and lower ureteral stones in prone position. On the basis of a meticulous stone localization and focusing, depth measurements were carried out under real-time ultrasonic guidance, the minimal distance between the cutaneous plane and the focal point being recorded only for definitely localized calculi. RESULTS: Ureteral calculi were significantly deeper than renal stones (p < 0.0001), but the distance from the cutaneous plane was statistically similar for upper and lower ureteral calculi. Stone depth was statistically affected by body mass index (BMI), patients with a BMI >25 having significantly deeper renal and ureteral calculi than subjects with a BMI < or =25 (p < 0.00001 and 0.01, respectively). Renal stones resisting SWL were significantly deeper than successfully treated calculi (p < 0.03). At the level of the ureter, the success rate after one SWL session was 85% for stones with a depth < or =110 mm and 57% for deeper stones, the difference being significant (p < 0.05). CONCLUSION: Stone depth has a significant influence on treatment outcome after piezoelectric SWL for both renal and ureteral calculi. We recommend particular attention be given to corpulent patients presenting with ureteral stones.

Adult↗
PubMed2000

Simple nephrectomy: retroperitoneal approach.

Direct extraperitoneal surgery has become the preferred approach to laparoscopic nephrectomy since the introduction of the balloon dilation method. The lateral decubitus position provides good exposure, but the prone position is used at some centers to gain better exposure with the aid of gravity. The open conversion rate ranges from 0 to 16% and the complication rate from 5% to 45%, with most complications being minor. Retroperitoneal laparoscopic simple nephrectomy is definitely superior to open nephrectomy as judged by analgesic use and recovery time. The higher complication rate and lower efficiency can be taken care of by experience and proper case selection.

Catheterization↗
PubMedDate not supplied

Modified Stryker frame for intraoperative positioning of the patient with burns.

Positioning large patients with burns for prone burn procedures can be very difficult, requiring operating room personnel to use a gang-lift technique. We have used the upper portion of a Stryker frame mounted to a standard operating room table base in more than 200 burn procedures in adults to move patients from the supine to the prone position, and back, without complication.

Burns↗
PubMed2003

Selective pulmonary vasodilation in acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is characterized by a marked maldistribution of pulmonary perfusion in favor of nonventilated, atelectatic areas of the lungs, and it is the main cause of pulmonary right-to-left shunting and hypoxemia. Therapeutic interventions to selectively influence pulmonary perfusion in ARDS became feasible with the introduction of inhaled nitric oxide, which provided a means not only to reduce pulmonary hypertension, but also to improve matching of ventilation to perfusion and, thus, hypoxemia. Clinical studies in ARDS subsequently demonstrated that the combination of inhaled nitric oxide with other interventions, such as positive end-expiratory pressure and prone positioning, yielded beneficial and additive effects on arterial oxygenation. Although the available randomized, controlled trials of this novel concept have so far failed to show an improved outcome in ARDS, inhaled nitric oxide is a clinically valuable option for the treatment of severe refractory hypoxemia in ARDS, and largely promoted the concept of selective pulmonary vasodilation in intensive care practice. Currently, aerosolization of various vasodilators, in particular prostaglandins, is under evaluation in models of acute lung injury and human ARDS. Ongoing research aims to augment the effectiveness of vasodilators with specific inhibitors of phosphodiesterases or by combination with intravenous vasoconstrictors. Consequently, several alternative ways to selectively modulate pulmonary vascular tone in patients with ARDS may be available in the near future. Cost-benefit analysis of these therapeutic options will largely determine their future perspective.

Administration, Inhalation↗
PubMed2004

Helical tomotherapy as a means of delivering accelerated partial breast irradiation.

A novel treatment approach utilizing helical tomotherapy for partial breast irradiation for patients with early-stage breast cancer is described. This technique may serve as an alternative to high dose-rate (HDR) interstitial brachytherapy and standard linac-based approaches. Through helical tomotherapy, highly conformal irradiation of target volumes and avoidance of normal sensitive structures can be achieved. Unlike HDR brachytherapy, it is noninvasive. Unlike other linac-based techniques, it provides image-guided adaptive radiotherapy along with intensity modulation. A treatment planning CT scan was obtained as usual on a post-lumpectomy patient undergoing HDR interstitial breast brachytherapy. The patient underwent catheter placement for HDR treatment and was positioned prone on a specially designed position-supporting mattress during CT. The planning target volume (PTV) was defined as the lumpectomy bed plus a 20 mm margin. The prescription dose was 34 Gy (10 fx of 3.4 Gy) in both the CT based HDR and on the tomotherapy plan. Cumulative dose-volume histograms (DVHs) were generated and analyzed for the target, lung, heart, skin, pectoralis muscle, and chest wall for both HDR brachytherapy and helical tomotherapy. Dosimetric coverage of the target with helical tomotherapy was conformal and homogeneous. "Hot spots" (> or =150% isodose line) were present around implanted dwell positions in brachytherapy plan whereas no isodose lines higher than 109% were present in the helical tomotherapy plan. Similar dose coverage was achieved for lung, pectoralis muscle, heart, chest wall and breast skin with the two methods. We also compared our results to that obtained using conventional linac-based three dimensional (3D) conformal accelerated partial breast irradiation. Dose homogeneity is excellent with 3D conformal irradiation, and lung, heart and chest wall dose is less than for either HDR brachytherapy or helical tomotherapy but skin and pectoral muscle doses were higher than with the other techniques. Our results suggest that helical tomotherapy can serve as an effective means of delivering accelerated partial breast irradiation and may offer superior dose homogeneity compared to HDR brachytherapy.

Brachytherapy↗
PubMed1988

Platypnea induced by worsening of VA/Q inhomogeneity in the sitting position in chronic obstructive lung disease.

We report a patient with COPD who experienced severe dyspnea with a decreased PaO2 in the sitting position, largely improved in the ventral prone position (platypnea). By using an isotopic method, we showed that this phenomenon is the result of a deleterious effect of the sitting position on regional ventilation/perfusion matching. We speculated that hypoxic vascular pulmonary constriction was deficient in our patient. This hypothesis is supported by a dramatically better matching of the VA/Q ratio after treatment with almitrine bismesilate, a drug that could potentiate hypoxic pulmonary vasoconstrictive reflexes.

Aged↗
PubMed1986

[Determination of heart size and measurements of blood vessels in chest imaging of 4 to 15-year-old children with a healthy cardiovascular system].

The standard heart size, i.e., heart diameters and heart volume, of normal children aged 4-15 years were obtained. In all cases requiring exact heart-size determination, heart volume calculation is mandatory in children as well as in adults. Statistical work to date has provided the precise calculation of heart volume from plain films in the upright position. Additional plain films in the prone position are unnecessary because there is no evidence of an orthostatic influence on heart volume in children. The percentiles of normal heart volume related to body weight, representing the best correlation to the individual data, are given as well as percentiles related to age. Furthermore, ratios of normal vessel size to the height of the 8th thoracic vertebral body, measured on the same plain film, are given. In addition, the ratio of upper-to-lower lung vessel size is calculated. These ratios are useful criteria in estimating normal vessel size and also in cases with increased pulmonary venous pressure.

Adolescent↗
PubMed1997

[Laparoscopic adrenalectomy].

Minimally-invasive adrenalectomy is a new and attractive procedure, which has advanced to the method of choice in the surgical treatment of benign adrenal diseases. This technique is contraindicated in the treatment of adrenal malignancies. The endoscopic removal of large benign adrenal tumors (> 6-8 cm) may be difficult. The preoperative management of the patients does not differ from the preparation for conventional adrenalectomy. Like in open adrenalectomy several different endoscopic approaches to the adrenals have been described: the transperitoneal approach with the patient in supine position, the transperitoneal approach in lateral position, the retroperitoneal approach in lateral position and the retroperitoneal approach in prone position. Excellent results have been achieved with all four techniques. The approaches with the patient in lateral position have the disadvantage that in case of bilateral adrenalectomy the patient has to be repositioned during the operation. Large tumors are more difficult to be removed with the retroperitoneal techniques, because of the limited space in the retroperitoneum. Operative times and conversion rates have been markedly reduced with increasing experience with these techniques.

Adrenal Gland Diseases↗
PubMed2003

Automated centerline for computed tomography colonography.

RATIONALE AND OBJECTIVES: A novel method to compute the centerline of the human colon obtained from computed tomography colonography is proposed. Two applications of this method are demonstrated: to compute local colonic distension (caliber), and to match polyps on supine and prone images. MATERIALS AND METHODS: The centerline algorithm involves multiple steps including simplification of the colonic surface by decimation; thinning of the decimated colon to create a preliminary centerline; selection of equally spaced points on the preliminary centerline; grouping neighboring points; and mapping them back to rings in the original colon. This method was tested on 20 human computed tomography colonography datasets (supine and prone examinations of 10 patients) and on a computer-generated colon phantom. RESULTS: Visual inspection of the colons and their centerlines showed the centerline to be accurate. For the colon phantom, the average error was only 1 mm. For 11 polyps visualized in both the supine and prone positions and found by computer-aided detection, the normalized distance along the centerline to each polyp was not significantly different on the supine and prone views (r = 0.999; P < .001). CONCLUSION: This method produces an accurate colon centerline that may be useful for flight path planning, matching detections on the supine and prone views, and computing local colonic distension.

Algorithms↗
PubMed2006

Combined supine and prone quantitative myocardial perfusion SPECT: method development and clinical validation in patients with no known coronary artery disease.

UNLABELLED: Acquisition in the prone position has been demonstrated to improve the specificity of visually analyzed myocardial perfusion SPECT (MPS) for detecting coronary artery disease (CAD). However, the diagnostic value of prone imaging alone or combined acquisition has not been previously described using quantitative analysis. METHODS: A total of 649 patients referred for MPS comprised the study population. Separate supine and prone normal limits were derived from 40 males and 40 females with a low likelihood (LLk) of CAD using a 3 average-deviation cutoff for all pixels on the polar map. These limits were applied to the test population of 369 consecutive patients (65% males; age, 65 +/- 13 y; 49% exercise stress) without known CAD who had diagnostic coronary angiography within 3 mo of MPS. Total perfusion deficit (TPD), defined as a product of defect extent and severity scores, was obtained for supine (S-TPD), prone (P-TPD), and combined supine-prone datasets (C-TPD). The angiographic group was randomly divided into 2 groups for deriving and validating optimal diagnostic cutoffs. Normalcy rates were validated in 2 additional groups of consecutive LLk patients: unselected patients (n = 100) and patients with body mass index >30 (n = 100). RESULTS: C-TPD had a larger area under the receiver-operating-characteristic (ROC) curve than S-TPD or P-TPD for identification of stenosis >or=70% (0.86, 0.88, and 0.90 for S-TPD, P-TPD, and C-TPD, respectively; P < 0.05). In the validation group, sensitivity for P-TPD was lower than for S- or C-TPD (P < 0.05). C-TPD yielded higher specificity than S-TPD and a trend toward higher specificity than P-TPD (65%, 83%, and 86% for S-, P-, and C-TPD, respectively, P < 0.001; vs. S-TPD and P = 0.06 vs. P-TPD). Normalcy rates for C-TPD were higher than for S-TPD in obese LLk patients (78% vs. 95%, P < 0.001). CONCLUSION: Combined supine-prone quantification significantly improves the area under the ROC curve and specificity of MPS in the identification of obstructive CAD compared with quantification of supine MPS alone.

Coronary Artery Disease↗
PubMed1999

Non-ventilatory treatment of acute hypoxic respiratory failure.

Severe acute hypoxic respiratory failure is uncommon but often fatal. Standard treatment involves high inspired oxygen concentrations, mechanical ventilation and positive end-expiratory pressure. Many other interventions have been used in parallel with conventional treatment or as rescue therapy when it fails, including extracorporeal gas exchange, prone positioning, inhaled vasodilators, exogenous surfactants and drugs which modify the inflammatory process. Nearly all these treatments improve arterial oxygenation or markers of lung injury. However, the relationship between oxygenation and survival in acute hypoxaemic respiratory failure is not established, so improved oxygenation cannot be used as a surrogate for survival. Randomised controlled trials are, therefore, needed to assess the effects of these treatments on mortality. In such trials, extracorporeal oxygenation and extracorporeal carbon dioxide elimination, surfactant, early methylprednisolone, and prostaglandin E1 offer no survival advantage over conventional therapy. Prophylactic ketoconazole and pentoxifylline appear to improve mortality in small studies in surgical and oncology patients respectively, and methylprednisolone improves mortality and morbidity in unresolving disease.

Acute Disease↗
PubMed1995

VATS resection of a mediastinal neurogenic dumbbell tumor.

Some posterior mediastinal tumors can be safely resected with video-assisted thoracic surgery (VATS), but the safety of resecting a dumbbell-shaped tumor has been questioned. This article reports the successful removal of a dumbbell-shaped cystic schwannoma at T4 using a posterior laminectomy and VATS, with the patient in the prone position.

Humans↗
PubMed1995

[Ultrasound morphologic parameters of female stress incontinence].

AIM: The study compared ultrasound parameters of the lower urinary tract with patients' age, number of previous pregnancies as well as the grade of incontinence. Furthermore, the influence of postural changes was studied. METHOD: Ultrasonographic examination of the vaginal introitus was performed on 222 patients using a 5 MHz scanner. The transducer was inserted along the body axis and a vertical plane was defined. RESULTS: Urinary stress incontinence was found to be associated with the occurrence of cystoceles, the finding of a funnel-like opening of the proximal urethra, an increased retrovesical angle beta, and finally with a descent of the bladder neck. However, there was no significant correlation between urethral length and the grade of stress incontinence. In patients without urinary incontinence, the retrovesical angle as well as the position of the bladder neck were strongly related to parity but did not correlate with the patients' age. There was no significant difference between parameters when the patients were straining in a prone or half-prone position. CONCLUSION: Sonomorphological pelvic floor disorder is based on previous pregnancies and correlates well with urinary stress incontinence.

Adult↗
PubMed1998

Positional changes and drug interventions in acute respiratory failure.

Acute respiratory failure is often a life-threatening condition that determines the outcome of acutely ill patients. This review discusses the physiological basis and results of two complementary approaches for the management of such patients: positional changes and drug interventions. In unilateral pulmonary disease locating the healthy lung in a dependent position may improve gas exchange; in bilateral involvement, as occurs in the acute respiratory distress syndrome (ARDS), both the theoretical principles and the observed benefits fully support the use of the prone position. The effect of vasoactive drugs on pulmonary circulation and gas exchange is also reviewed. Selective vasodilators, such as inhaled nitric oxide and prostacycline-12, may provide a useful alternative in ARDS.

Acute Disease↗