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Results for “Prone Position”

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PubMed2002

Bronchioloalveolar carcinoma masked by gravity-dependent gradient on computed tomography.

A 78-year-old woman was found to have a small bronchioloalveolar carcinoma with ground-glass attenuation in the gravity-dependent gradient in the left lower lobe during a preoperative chest computed tomography (CT) evaluation, which was performed for previously-diagnosed adenocarcinoma of the right upper lobe. To remove the gravitational effect of the CT, the patient underwent a thin section CT in the prone position. Then, a ground-glass attenuation was revealed clearly in the left lower lobe. Postoperative pathological diagnosis was synchronous multiple bronchioloalveolar carcinomas, stage IA. This case suggests that focal areas of ground-glass attenuations on a thin-section CT in patients with BAC would be considered to be multicentric development of BAC. CT with the patient in the prone position helps to exclude the gravitational effect and narrow the differential diagnosis of ground-glass opacity, including localized forms of BAC.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2001

Ventilatory responses to hypercapnia in divers and non-divers: effects of posture and immersion.

The aim of this study was to determine the effects on respiratory drive of two factors, one mechanical (lung volume) and one chemical (sensitivity to hypercapnia), that are involved in determining the breath-hold duration (BHD). Functional residual capacity was measured by helium dilution with the subject seated in air, seated in water and in the prone position in water. Hyperoxic hypercapnia rebreathing (Read's method) was carried out under identical environmental conditions to assess the effects of CO2 pressure on respiratory centre output by measuring ventilation, mean inspiratory flow and occlusion pressure. Sixteen healthy volunteers were tested. 8 trained divers and 8 non-divers. Functional residual capacity decreased for the postures seated in water (30.8%-34.8%) and for prone position in water (20.3%-20.9%) when compared to the posture seated in air (P<0.0001), all subjects pooled. No difference was found between groups. The slopes of the linear regression, which characterised the sensitivity to CO2 and were determined with the rebreathing tests, revealed differences between the two populations (ventilation: P < 0.0001; mean inspiratory flow: P < 0.05). No difference was found for occlusion pressure or between the different postures. These results confirmed a lower sensitivity to CO2 for trained divers. This adaptation was shown to decrease respiratory centre activity at the origin of the breath-hold breaking point. The immersion, did not influence respiratory drive, despite a decrease in lung volumes. The authors suggest that these findings may be explained by a specific apnoea training and a pronounced bradycardia in immersion.

Adaptation, Physiological↗

PubMed2003

CO2-enhanced CT imaging for the detection of pulmonary emboli: feasibility study in a porcine model.

RATIONALE AND OBJECTIVES: The authors investigated the feasibility of using computed tomography (CT) with CO2 gas as a negative contrast agent for detecting pulmonary emboli in a porcine model. MATERIALS AND METHODS: Seven pigs with or without pulmonary emboli underwent thoracic imaging with multi-detector row spiral CT. To identify optimal injection and scanning protocols, the first four pigs were scanned repeatedly in the supine and prone positions with different scan delays (10, 15, and 20 seconds) and different volumes of CO2 (60, 120, 180, and 240 mL), which were hand infused (each infusion took 10-15 seconds). The last five pigs with emboli were scanned with iodinated contrast medium and then rescanned with 120 or 180 mL of CO2. The CO2 volumes and scan delays were qualitatively assessed. The supine and prone CT scans and the number and location of thrombi depicted in the CO2- and contrast material-enhanced CT scans were compared. RESULTS: Because the pulmonary artery in pigs is in the posterior anatomy, the prone position was more effective than the supine position with CO2 enhancement. An infusion of 120 mL of CO2 was sufficient to enhance the entire pulmonary artery, and scanning timed to coincide with the completion of infusion was the most effective. Both the CO2- and contrast-enhanced CT scans demonstrated all thrombi. Thrombi were more apparent on the CO2-enhanced CT scans than on the contrast-enhanced scans because of the high contrast interface between soft tissue and gas. However, two of the seven pigs with thrombi experienced abrupt cardiac arrest after CO2-enhanced scanning and could not be resuscitated. The cause of these events was not determined in the current study. CONCLUSION: The CT depiction of pulmonary emboli is feasible with CO2 gas as a negative contrast agent and may even be superior to that with iodinated contrast media. Further studies are required to evaluate the safety of this method and to develop an improved delivery of CO2 gas for this application.

Animals↗

PubMed1994

[Right ventricular function and postural changes during surgery of the lumbar spine].

The aim of the study was to assess the effects of the sitting prone position on right ventricular function in a group of patients requiring low back surgery with using of right heart catheterization with a low fast response thermodilution technique. This posture involves moderated hemodynamic effects. A discrete right ventricle impairment characterised by a decreased compliance was observed and may be due to a moderate compression by the sternum and was improved by fluid challenge. Thus, the sitting prone position appears a safe position.

Humans↗

PubMed2002

Quality of virtual colonoscopy in patients who have undergone radiation therapy or surgery: how successful are we?

OBJECTIVE: In patients who have a history of abdominopelvic radiation, surgery, or both, conventional colonoscopy may fail to examine the entire colon. The purpose of this study is to assess whether high-quality virtual colonoscopy can be achieved in this patient population. MATERIALS AND METHODS: After colonic cleansing, 61 patients (16 men and 45 women; mean age, 64 years; age range, 27-81 years) underwent 63 virtual colonoscopy examinations after using either single- or multidetector CT (slice thickness, 3.75-5.0 mm; table speed, 1.7-11.25 cm/sec; pitch, 1.5-3.0; and overlapped reconstructions, 1.95-2.5 cm) in supine and prone positions after IV administration of 1 mg of glucagon and rectal air insufflation. Conventional two-dimensional axial images were analyzed on a PACS (picture archiving and communication system) workstation. Two radiologists, who were unaware of patient history, independently evaluated the colonic distention on a 4-point scale (4 = optimal distention) and fluid retention on a 3-point scale (3 = no fluid) for all segments of the colon in patients who were imaged in both the supine and prone positions. Segmental and total average colon scores were calculated. RESULTS: Forty-one patients (65%; 43 examinations, 67%) underwent prior surgery, radiation, or both (surgery, n = 29; radiation, n = 3; both, n = 11). The average overall colonic distention and fluid retention for this group was 3.13 and 2.38, respectively, versus 3.24 and 2.3 in the control group (p = not significant). CONCLUSION: High-quality examinations were achieved in patients who had previously undergone radiation, surgery, or both with no clinically significant difference in distention or fluid retention compared with the controls.

Abdomen↗

PubMed2003

Low-dose multislice spiral computed tomography in acute lung injury: animal experience.

RATIONALE AND OBJECTIVES: To compare low-dose multislice spiral CT (MSCT) with a standard protocol for the evaluation of acute lung injury (ALI) in an animal model. MATERIALS AND METHODS: Eleven healthy intubated pigs (weight: 32.4 kg +/- 1.9 kg) underwent lung lavage to induce experimental lung injury before CT examinations. Scanning was performed using a MSCT-technique. The entire chest was scanned using a thin-collimated protocol (140 kV; 100 mAs). The examinations were performed in inspiratory breath-hold in supine and in prone positions. Scanning was repeated after reduction of the tube current time product down to 20 mAs. All other parameters were kept constant. Subjective image quality was rated using a six-point scale by three experienced radiologists. In addition, objective criteria, based on signal to noise measurements, were assessed. Finally, the extent, localization, and distribution of lung opacities was analyzed using dedicated postprocessing software. RESULTS: Subjective image quality was rated inferior in the low-dose MSCT-examinations (prone position: 2.1 vs. 3.0; supine position: 1.5 vs. 2.5). Hence, pixel noise was nearly doubled. However, exact information about the extent, localization and distribution of lung opacities was provided. There were no statistically significant differences between standard and low-dose MSCT in this respect. CONCLUSIONS: In the animal experiments, low-dose MSCT-scanning did not impair the diagnostic accuracy in ALI, offering an advantageous reduction of radiation exposure.

Animals↗

PubMedDate not supplied

The case for an in situ lesser saphenous vein bypass.

In situ lesser saphenous vein (LSV) graft has been advocated in cases where the greater saphenous vein is not available and the target arteries are confined to the lower leg. This is often the case of diabetic patients, whose occlusive disease pattern typically affects the tibioperoneal vessels, sparing the femoropopliteal segment. The in situ technique offers the potential advantages of decreasing surgical trauma to the vein and its vasa vasorum, better size-matching between vein and artery at the anastomoses, and improving hemodynamics. The authors reviewed the use of in situ LSV graft with attention to its indications and technical requirements. A 73- and a 76-year-old man presented with critical limb ischemia. Both had a history of diabetes, chronic renal failure, and previous use of the greater saphenous veins for coronary or peripheral bypasses. Both had good femoropopliteal inflow and tibioperoneal disease with single runoff through the distal peroneal and common plantar arteries, respectively. Venous mapping showed diminutive veins, with exception of an adequate ipsilateral lesser saphenous vein. The patients were placed in prone position for a posterior approach. The lesser saphenous veins were exposed through a longitudinal incision. Proximal anastomosis was based on the popliteal artery, exposed through the same incision. A successful in situ lesser saphenous vein bypass was performed by using the common plantar and the distal peroneal artery as target vessels. Both bypasses were patent at 24 and 18-months' follow-up, respectively. Selection criteria for in situ LSV bypass are patent femoral arteries; accessible target vessels in prone position through a medial, posterior, or lateral approach; and adequate LSV in diameter and length. In the authors' experience, in situ LSV bypass is a safe and simple option that offers successful distal revascularization.

Aged↗

PubMed1995

Non-invasive continuous haemodynamic and PETCO2 monitoring during peroperative cardiac arrest.

We describe a cardiac arrest which occurred during general anaesthesia in the prone position for surgical correction of lumbar kyphosis in a patient with Marfan's syndrome. Peroperative monitoring was routine with ECG, non-invasive arterial pressure, oximetry, PETCO2 and central venous pressure, plus aortic blood flow and and systolic time intervals via an oesophageal echo-Doppler device. Forty-five minutes after the start of surgery, a sudden decrease in aortic blood flow followed by a decrease in PETCO2 suggested acute cardiac failure despite continuation of the ECG signal. Initial CPR in the prone position produced a slight increase in PETCO2. When the patient was turned to the supine position and the legs elevated, chest compression was more efficient and spontaneous circulation was rapidly restored. Circulatory arrest could be explained by incompletely treated hypovolaemia, or by myocardial depression (decrease in aortic blood flow and lengthened pre-ejection period) combined with excessive hypotension in a patient with Marfan's syndrome, thus compromising coronary blood flow producing ST segment depression. Continuous non-invasive aortic blood flow and PETCO2 monitoring proved valuable in the early detection and treatment of circulatory arrest and in the evaluation of the efficiency of peroperative CPR.

Adolescent↗

PubMed2004

[Stability of postoperative visual acuity after rt-PA -SF6-treatment of submacular hemorrhage in age-related macular degeneration].

PURPOSE: Treatment of submacular hemorrhage with recombinant tissue plasminogen activator(rt-PA) and SF6 induces blood displacement out of the fovea by maintaining prone positioning. The underlying disease, e.g. the choroidal neovascularisation remains untreated. Nevertheless, it has been noted that the visual results of this method are more favorable than those expected in the natural course. Contributing long-term results the present study intends to give more information concerning this phenomenon. METHOD: A total of 45 consecutive eyes were treated using a standardized procedure (duration of hemorrhage < or =1 week, area of hemorrhage 1-10 disc areas, 50 gammag rt-PA, 0.5 ml SF6 24 h later, prone positioning for 3 days). Those with a follow-up of > or =6 months were included in the study. RESULTS: From 25 patients a total of 25 eyes fulfilled the criteria. Postoperative visual acuity(3-7 days) was improved or unchanged in 19 eyes and worse in 6 eyes. Comparison of postoperative visual acuity after follow-up of an average of 14.2 months (range 6-28 months) revealed an improvement in 10 eyes, no change in 7 eyes and a deterioration in 8 eyes. A second treatment was performed in 2 eyes and photocoagulation in 1 eye. CONCLUSION: After more than 1 year the postoperative visual acuity was stable or even better in about two-thirds of the eyes therefore treatment with rt-PA and SF6 may also influence the choroidal neovascularisation.

Aged↗

PubMed1987

The effect of the respiratory cycle on mediastinal and lung dimensions in Hodgkin's disease. Implications for radiotherapy gated to respiration.

Changes in mediastinal and lung dimensions during respiration were studied to assess the potential of radiotherapy gated to respiration to minimize normal tissue irradiation. Twelve patients with mediastinal Hodgkin's disease were assessed using chest radiographs and thoracic computed tomography (CT) scans both during quiet breathing and at maximum inspiration in the standing, supine, and prone positions. A simple measure of the bulk of mediastinal disease, the ratio of the width of mediastinal mass to thoracic diameter, was determined from posteroanterior (PA) chest radiographs. The volumes of mediastinum, irradiated and protected lung if anteroposterior (AP) and PA mantle fields were used were determined from sequential thoracic CT scans and three-dimensional treatment planning and compared at quiet breathing and deep inspiration. The mediastinal width to thoracic diameter ratio decreased from quiet breathing to deep inspiration an average of 3%, 9%, and 11% for the standing, supine, and prone positions, respectively. Lung volumes as measured from the thoracic CT scans showed that on average, 8% more lung was protected at deep inspiration than at quiet breathing, independent of treatment position. The maximum increase in the percentage of protected lung from quiet breathing to deep inspiration was seen in patients with extensive mediastinal adenopathy suggesting that radiotherapy gated to respiration may be most advantageous in the subset of patients.

Hodgkin Disease↗

PubMed1980

Hydrostatic weighing at residual volume and functional residual capacity.

Hydrostatic weighing (HW) was performed at both residual volume (RV) and functional residual capacity (FRC) to determine if underwater weighing at different lung volumes affected the measurement of body density. Subjects were 43 males, 18-25 yr. Subjects were submerged in the prone position, and the lung volume was measured by helium dilution at the time of the underwater weighing. Underwater weight was first assessed at FRC followed by assessment at RV. Changes in lung volume were accurately reflected in the underwater weight. Body density (D) was not different with the use of the FRC (mean D = 1.0778) or RV (mean D = 1.0781) data. Percent fat values for the FRC and RV data were 9.3 +/- 5.4 and 9.2 +/- 5.1%, respectively, and were not statistically different. The results indicate that the difference between percent fat determinations by HW in the prone position at FRC and RV is negligible. Because measurement of underwater weight at FRC is more comfortable for the subject, this may be the method of choice when the lung volume can be measured during the underwater weighing.

Adolescent↗

PubMed1999

T2* and proton density measurement of normal human lung parenchyma using submillisecond echo time gradient echo magnetic resonance imaging.

OBJECTIVE: To obtain T2* and proton density measurements of normal human lung parenchyma in vivo using submillisecond echo time (TE) gradient echo (GRE) magnetic resonance (MR) imaging. MATERIALS AND METHODS: Six normal volunteers were scanned using a 1.5-T system equipped with a prototype enhanced gradient (GE Signa, Waukausha, WI). Images were obtained during breath-holding with acquisition times of 7-16 s. Multiple TEs ranging from 0.7 to 2.5 ms were tested. Linear regression was performed on the logarithmic plots of signal intensity versus TE, yielding measurements of T2* and proton density relative to chest wall muscle. Measurements in supine and prone position were compared, and effects of the level of lung inflation on lung signal were also evaluated. RESULTS: The signal from the lung parenchyma diminished exponentially with prolongation of TE. The measured T2* in six normal volunteers ranged from 0.89 to 2.18 ms (1.43 +/- 0.41 ms, mean +/- S.D.). The measured relative proton density values ranged between 0.21 and 0.45 (0.29 +/- 0.08, mean +/- S.D.). Calculated T2* values of 1.46 +/- 0.50, 1.01 +/- 0.29 and 1.52 +/- 0.18 ms, and calculated relative proton densities of 0.20 +/- 0.03, 0.32 +/- 0.13 and 0.35 +/- 0.10 were obtained from the anterior, middle and posterior portions of the supine right lung, respectively. The anterior-posterior proton density gradient was reversed in the prone position. There was a pronounced increase in signal from lung parenchyma at maximum expiration compared with maximum inspiration. The ultrashort TE GRE technique yielded images demonstrating signal from lung parenchyma with minimal motion-induced noise. CONCLUSION: Quantitative in vivo measurements of lung T2* and relative proton density in conjunction with high-signal parenchymal images can be obtained using a set of very rapid breath-hold images with a recently developed ultrashort TE GRE sequence.

Artifacts↗

PubMed1980

[The glider. Postural kinetic behavior during the pre-locomotor period in infants].

Soaring movements-in an opisthotonic posture-which appear between 3 and 10 months when the infant is in a prone position, have been observed with cinematographic recordings. This is a postural and kinetic activity which takes place during the first year's development; i is a transitional stage leading to intentional propulsive movements. This activity may become a repetitive one for some children, especially between 4 and 7 months; at this peak period, it takes on an unusual aspect, not only because of the "aerial" attitude but also because of the rhythmicity of the postural changes which characterize it. This behavior has been studied in its evolutionary forms, its individual characteristics, and its emotional expressions. Hovering movements are localized in the neuro-psychological evolution of the infant (tonico-postural evolution, acquisition of balance in a prone position, alternating postures, propulsive movements). The conditions which set off and quieten this activity explain the dynamics of its functioning between movements to which the baby is submitted and deliberate ones, between constraint and pleasure.

Child Development↗

PubMed2000

Predictors of independent walking in children with spastic diplegia.

A prospective study was carried out to identify predictors of independent walking in 31 children with either spastic diplegia or triplegia, observed from the age of 9 to 18 months (mean, 11 months) and followed for a mean period of 30 months (range, 24 to 36 months). Mean age at most recent examination was 41 months (range, 36 to 54 months). We used an 18-item scheme to chart the acquisition, from the prone position, of prelocomotor, sitting, and locomotor skills. Examinations were conducted every 6 months and videotaped according to a standardized procedure. At latest assessment 18 (58%) of the 31 children had achieved walking, 7 (23%) independently and 11 (35%) with assistance; 13 (42%) did not achieve walking. Ambulatory status was related to developmental quotient and visual acuity: all the children who became independent walkers had normal visual acuity and in 86% of cases a normal general development quotient. Moreover, we found a significant correlation between the number of gross motor skills achieved and the rate of achievement before 2 years of age and ambulatory status at 3 to 5 years of age. Ability to put weight on the hands while prone and to roll from supine to prone position by 18 months of age were significantly related to independent walking, while ability to sit without support was predictive only at around 24 months of age.

Cerebral Palsy↗

PubMed1996

Hemodynamic changes after retroperitoneal CO2 insufflation for posterior retroperitoneoscopic adrenalectomy.

Intraoperative complications and hemodynamic alterations during posterior capnoretroperitoneoscopic adrenalectomy in the prone position were investigated in 16 consecutive patients using invasive hemodynamic monitoring. Under general anesthesia with propofol and fentanyl, hemodynamic changes were made before (M1) and during retroperitoneal CO2 insufflation (15 mm Hg) [M2]; 20 mm Hg [M3]. Retroperitoneal insufflation resulted in a significant increase of cardiac output (+72%), stroke volume (+42%), mean arterial pressure (+39 %), and mean pulmonary arterial pressure (+36%). Although retroperitoneal inflation was accompanied by a significant increase of central venous pressure (+37%), an increase of preload may have lead to higher filling pressures. Heart rate, systemic vascular resistance, and pulmonary vascular resistance did not show significant changes. One pneumothorax and two cutaneous emphysemas occurred. We have demonstrated, in a small number of patients, that retroperitoneal CO2 insufflation for posterior capnoretroperitoneoscopic adrenalectomy in the prone position results in hemodynamic changes without apparent adverse effects.

Adolescent↗

PubMed2001

Management of oxygenation in pediatric acute hypoxemic respiratory failure.

The prognosis for patients with acute respiratory distress syndrome (ARDS) in adults and children has improved since its formal acceptance as a clinical entity in 1967. Because acute hypoxemic respiratory failure is the hallmark of acute lung injury and ARDS, the management of oxygenation is crucial. Physicians managing pediatric patients with acute lung injury or ARDS are faced with a complex array of options influencing oxygenation. Certain treatment strategies can influence clinical outcomes, such as a lung-protective ventilation strategy that specifies a low tidal volume (6 mL/kg) and a plateau pressure limit (30 cm H(2)O) (Acute Respiratory Distress Network, N Engl J Med 2000;342:1301-1308). Other lung-protective strategies such as different levels of positive end-expiratory pressure, altered inspiratory:expiratory ratios, recruitment maneuvers, prone positioning, and extraneous gases or drugs may impact clinical outcomes but require further clinical study. This paper reviews state-of-the-art strategies on the management of oxygenation in acute hypoxemic respiratory failure and attempts to guide pediatric pulmonologists in managing children with respiratory failure.

Acute Disease↗

PubMed1997

Hydro-CT in patients with gastric cancer: preoperative radiologic staging.

A total of 35 patients (age range 35-78 years) with gastric tumors on the lesser curve, or in the antro-pyloric region, underwent angio-CT in the prone position after filling the stomach with 500 ml of water and intravenous administration of glucagon. The films were reviewed by three radiologists independently, staging each tumor according to the TNM classification preoperatively. The overall accuracy of tumor staging ranged between 66-77 %, overstaging between 17-25 %, and understaging between 3-8.5 %. The diagnostic sensitivity, specificity, and accuracy for serosal invasion ranged between 90 and 100, 76 and 84, and 80-88 %, respectively, and the overall accuracy for N staging was 46, 48, and 51 % for the three observers. If, however, N1 and N2 tumors were considered as a single group, N-stage accuracy increased, ranging between 63 and 77 %. The "K test" for analyzing the interobserver agreement was 60 %, i. e., the diagnostic results are reproducible. Water filling of the stomach optimizes visualization of the gastric wall on contrast-enhanced CT. The prone position and drug-induced hypotony allows for good distension without any disturbing artifact reduction obscuring the lower gastric body.

Adult↗

PubMed2001

[Bowel perforation after extracorporeal shock wave lithotripsy: a case report].

A case of intestinal perforation caused by ESWL for left ureteral calculus is reported. A 69-year-old male underwent the graft replacement for bilateral iliac aneurysm in March, 1996. In February, 1999, there appeared left flank pain, and a diagnosis of left ureterolithiasis was made by radiological examination. On March 29 he was admitted to our department for ESWL. On March 30, ESWL for calculus in the pelvic region was performed with the patient in the prone position. The patient complained of the left lower abdominal pain immediately after ESWL, but no muscular defense was observed. Since the pain was not relieved, CT was performed on March 31, but no evident abnormal finding was found. Thereafter the pain continued and on April 2 muscular defense was also noted. On CT performed a second time, free air and evidence of ileus were found, so emergency operation was performed. Two perforations about 2 mm in size were found in the jejunum 130 cm from the Treitz' ligament, which led to diagnosis of intestinal perforation due to ESWL. The patient followed a satisfactory postoperative course and was discharged on April 23. There has been only one reported case of intestinal perforation due to ESWL. It is a very rare complication. However, this complication should be taken into consideration where the patient has the history of abdominal surgery and where ESWL was performed with the patient in the prone position.

Aged↗