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Results for “Prone Position”

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At least 991 records · Page 55Linked to original sources

PubMed2001

A simple method of radiation treatment of craniospinal fields with patient supine.

PURPOSE: To describe a procedure for supine craniospinal radiation treatment. METHODS AND MATERIALS: The procedure is described as carried out with a 100 cm isocenter linear accelerator and compatible simulator. Treatment is with a single PA directed spinal field abutting lateral directed cranial fields. Abutment of the fields is established by placement, under direct observation, of the edges of the light fields at a mark placed on the anterior skin surface and subtraction of a calculated distance from the collimator readout length of the cranial field. RESULTS: The precision and reproducibility of field edge placement at the abutment line appears to be as good as for treatment in the prone position. This can be verified with port films. CONCLUSION: Supine craniospinal treatment is a reliable and convenient alternative to treatment in the prone position.

Brain Neoplasms↗

PubMedDate not supplied

[Effects of the ventral position on blood gas in infants during sleep].

In order to study the role of the prone position upon a possible ventilatory depression during sleep, we have studied polygraphically 29 infants sleeping prone and supine. The infants were in good health and had a mean age of 18.7 weeks. Transcutaneous oxygen and carbon dioxide pressures were recorded continuously. No significant change was seen in either body position for transcutaneous O2 and CO2, heart rate and respiratory rate. It is concluded that in the sleeping infant the prone position does not induce a change in the variables measured; no indication was found that there is an unfavorable effect of the prone position upon ventilatory adaptation during sleep.

Carbon Dioxide↗

PubMed2005

The use of a laryngeal mask airway for emergent airway management in a prone child.

A 5-yr-old girl with Arnold-Chiari Malformation, Type 1, was accidentally tracheally extubated while positioned prone in a Mayfield neurosurgical headrest during a decompressive craniectomy and cervical laminectomy. While preparations were being made to return the patient to the supine position for reintubation, we placed a laryngeal mask airway (LMA) without difficulty. The child was kept in the prone position with the LMA in place using positive-pressure ventilation for the remainder of the operation. This case report emphasizes the practical, emergent use of a LMA to secure the airway of a pediatric patient in the prone position after accidental extubation.

Child, Preschool↗

PubMed1992

Unilateral blindness as a complication of patient positioning for spinal surgery. A case report.

Extreme care must be used in positioning patients for surgery in a prone position. A padded Mayfield headrest may not be appropriate for all patients undergoing spinal surgery, as exophthalmus or a flattened nasal bridge may allow transmission of pressure to the globe. Our current approach is to use supplementary foam rubber support, with repeated, meticulous attention to keeping the eyes free from all pressure. Finally, unexplained intraoperative occurrence of a bradyarrhythmia or conduction disturbance may signal increased intraorbital pressure during general anesthesia.

Adult↗

PubMed1994

Augmentation of blood flow in limbs with occlusive arterial disease by intermittent calf compression.

PURPOSE: This study was designed to investigate the effect of intermittent calf compression on popliteal arterial blood flow and to see how flow is influenced by position of the subject and by arterial blood pressure at the ankle. METHODS: Volume flow in the popliteal artery of subjects in the sitting and prone positions was measured with duplex ultrasonography before inflation and immediately after deflation of a pneumatic cuff placed around the calf. Eleven legs of control subjects and 41 legs of patients with symptoms (32% patients with diabetes) with decreased ankle pressure were studied. Cuffs were inflated for 2 seconds at pressures ranging from 20 to 120 mm Hg. RESULTS: An increase in arterial blood flow of two to eight times (mean 4.4 +/- 2.0) was found on deflation of the cuff in seated control subjects. Little change in flow was observed when the subjects were in the prone position. In seated patients with arterial obstruction, the mean increase in arterial flow was 3.2 +/- 1.6 times the resting flow. Little correlation was found between the maximum increase in flow and the ankle/brachial index. CONCLUSIONS: An increased arteriovenous pressure gradient accounts for some but not all of the flow increase, much of which must be attributable to transient vasodilatation. Because the increase in flow does not depend on an increased inflow pressure and was not adversely affected by a low resting ankle-brachial pressure index or a low toe-pressure, intermittent external limb compression may deserve investigation as a possible adjunct to the nonoperative treatment of patients with severe arterial insufficiency.

Adult↗

PubMed1997

Coaxial technique: approach to breast core biopsies.

PURPOSE: To assess the feasibility of the coaxial core breast biopsy technique performed under stereotactic and ultrasound (US) guidance in vitro and in vivo. MATERIALS AND METHODS: Biopsies were performed in vitro and in vivo with a coaxial technique. In vitro, the true needle-tip deviation was measured with a breast phantom on a stereotactic device with alteration of x and y axes. In vitro US studies were performed to evaluate the optimal technique for harvesting sufficient material for histologic work-up. In 205 patients, coaxial biopsy was performed in 210 suspicious lesions under US (61 lesions) or stereotactic (patient in the sitting position, n = 67; patient in the prone position, n = 82) guidance. In addition, the coaxial system was used for preoperative localization. Surgery and histologic work-up were performed in all cases. RESULTS: In vitro, the true needle-tip deviation was found to be less than indicated on the stereotactic device. A factor was introduced to correct this error. For US guidance, angulation or rotation of the coaxial needle within the lesion proved to be the best technique to increase the size of histologic specimen. Of the 210 lesions, 112 were benign and 98 were malignant. Agreement between biopsy results and final postsurgical histologic analysis was found in 205 cases (98%). CONCLUSION: The coaxial breast biopsy technique is an accurate, simple, and time-saving method performed under stereotactic or US guidance.

Adult↗

PubMed1986

Pneumocephalus: effects of patient position on the incidence and location of aerocele after posterior fossa and upper cervical cord surgery.

The incidence of pneumocephalus and factors contributing to its occurrence were studied retrospectively in 100 consecutive patients who underwent posterior fossa or cervical cord surgery in the sitting, park-bench, and prone positions. Supine skull x-ray films taken immediately postoperatively were used to determine the presence of intracranial air. Surgery in the sitting position uniformly resulted in pneumocephalus (32/32 patients). Pneumocephalus also occurred frequently among patients in the park-bench (29/40) and prone positions (16/28). Intraventricular air occurred more frequently when patients were in the sitting position (25/32) than in the two other surgical positions (3/29 and 4/16, respectively, P less than 0.001). The high incidence of pneumocephalus and of intraventricular air that occurred when patients were in the sitting position is attributed to the large amount of cerebrospinal fluid drained due to gravitational effect. When surgical position is considered one of the contributing factors, only positions significantly affected the frequencies of pneumocephalus and intraventricular air accumulation. None of the 77 patients with pneumocephalus suffered neurologic change related to the presence of intracranial air. We conclude the following: pneumocephalus commonly occurs after posterior fossa or cervical cord surgeries, particularly when the surgery is performed in the sitting position; neurologic change caused by pneumocephalus is a rare complication after posterior fossa craniotomy; when a patient with coexisting hydrocephalus undergoes surgery, if the patient is in the sitting position, there is an increased risk of trapping a large amount of intracranial air.

Adolescent↗

PubMedDate not supplied

[Difference between arterial and end-tidal carbon dioxide tension during surgery of lumbar herniated disk in general anesthesia].

OBJECTIVE: To determine the correlation of PaCO2 and ETCO2 during operations for lumbar disk herniation in prone position: the influence of position and deliberate hypotension. DESIGN: Prospective, to compare PaCO2, ETCO2, pH, SBE, Pa max, in a group of 10 patients undergoing elective intervention for lumbar disk herniation in prone position and in a control group of 10 patients undergoing interventions for elective non traumatologic orthopaedic surgery of the lower limbs in supine position. SETTING: Orthopaedic department of a non teaching hospital. MEASUREMENTS AND MAIN RESULTS: The results for the patients of the supine group were: mean PaCO2 35.26 mmHg (SD 3.045), mean P(a-ET)CO2 3.46 mmHg (SD 1.898), mean pH 7.433 (SD 0.044), mean SBE - 1.16 (SD 1.718), mean Pa max 122.5 mmHg (SD 17.989). In the prone group: mean PaCO2 30.3 mmHg (SD 5.819), mean P(a-ET)CO2 1.4 mmHg (SD 4.445), mean pH 7.430 (SD 0.052), mean SBE-3.93 (SD 3.255), mean Pa max 100.3 (SD 10.945). The difference was significant (p < 0.05) for pH, PaCO2, SBE; in the prone group the variability of P(a-ET)CO2 was greater and the values related with SBE. CONCLUSIONS: ETCO2 is a useful monitoring for PaCO2 in the situation evaluated but the accuracy of the correlation with PaCO2 is lesser than during standard surgical techniques, the metabolic acidosis observed is probably related to the effects of the peculiar position and the anaesthetic technique.

Adult↗

PubMed2002

Management of the acute respiratory distress syndrome.

Significant advances have occurred in the knowledge of the pathogenesis of ARDS. It is now recognized that ARDS is a manifestation of a diffuse process that results from a complicated cascade of events following an initial insult or injury. Mechanical ventilation and PEEP are still important components of supportive therapy. To avoid ventilator-associated lung injury there is emphasis on targeting ventilator management based on measurement of pulmonary mechanics. For those with resistant hypoxia and severe pulmonary hypertension adjunctive modalities, such as prone positioning and low-dose iNO, may provide important benefit. Alternative modes of supporting gas exchange, such as with partial liquid ventilation and extracorporeal gas-exchange, may serve as rescue therapies. Advances in cell and molecular biology have contributed to a better understanding of the role of inflammatory cells and mediators that contribute to the acute lung injury and the pathophysiology of the syndrome that manifests as ARDS. Based on this new understanding, the potential targets for intervention to ameliorate the systemic inflammatory response have proliferated. Examples include the cytokine network and its receptors, antioxidants, and endothelins. Apart from the challenge of testing these agents in experimental models, it seems likely that determination of the optimum combination of agents will become an equally important endeavor. A particular challenge is to develop better methods of predicting which of the many at-risk patients will go on to full-blown ARDS and MODS, thereby targeting subgroups of patients most likely to benefit from anti-inflammatory therapies. Similarly, the adverse effects of immunosuppressive therapy may be diminished by improved, perhaps molecular, techniques to detect microbial pathogens and permit differentiation between Systemic inflammatory response syndrome and sepsis.

Animals↗

PubMedDate not supplied

[Continuous lateral rotation or kinetic therapy: an update of knowledge].

Acute lung injury and, when extreme, acute respiratory distress syndrome, are thought to be expression of a diffuse and overwhelming inflammatory reaction of the pulmonary capillary membrane to a variety of causes. The ventilatory support is essential in this patients. In the last years we know the significance of the postural treatment in this type of patients through the prone positioning. The continuous lateral rotation therapy or kinetic therapy (KT) is the new manner by other positioning beside the technological advances. Lowly it's introducing in our setting. The follow article would respound the next questions: What's the KT? How must to make the KT? What recommendations have been offered by specialists from the complications? Which is it efectivity?

Humans↗

PubMed2003

ARDS with severe hypoxia--aeromedical transportation during prone ventilation.

Severe hypoxia, despite maximal conventional respiratory support, is one of the few remaining limitations to aeromedical transportation. A case of a 35-year-old female, who was referred 36 hours following major trauma for transfer by air to a tertiary center, is presented. At the time of referral the PaO2/FiO2 ratio was 48. Usual manoeuvres to improve oxygenation had only minimal impact. The patient was turned and subsequently transported prone with resultant improvement in PaO2/FiO2 ratio to 260. There were no patient- or transport-related adverse events. The implication of prone positioning during aeromedical transportation is discussed.

Adult↗

PubMed2003

Pulmonary and extrapulmonary acute respiratory distress syndrome are different.

Acute respiratory distress syndrome (ARDS) can be derived from two pathogenetic pathways: a direct insult on lung cells (pulmonary ARDS (ARDSp)) or indirectly (extrapulmonary ARDS (ARDSexp)). This review reports and discusses differences in biochemical activation, histology, morphological aspects, respiratory mechanics and response to different ventilatory strategies between ARDSp and ARDSexp. In ARDSp the direct insult primarily affects the alveolar epithelium with a local alveolar inflammatory response while in ARDSexp the indirect insult affects the vascular endothelium by inflammatory mediators through the bloodstream. Radiological pattern in ARDSp is characterised by a prevalent alveolar consolidation while the ARDSexp by a prevalent ground-glass opacification. In ARDSp the lung elastance, while in ARDSexp the chest wall and intra-abdominal chest elastance are increased. The effects of positive end-expiratory pressure, recruitment manoeuvres and prone position are clearly greater in ARDSexp. Although these two types of acute respiratory distress syndrome have different pathogenic pathways, morphological aspects, respiratory mechanics, and different response to ventilatory strategies, at the present, is still not clear, if this distinction can really ameliorate the outcome.

Airway Resistance↗

PubMed2006

Update in ARDS management: recent randomized controlled trials that changed our practice.

In the last 7 years, 14 randomized controlled trials in patients with acute respiratory distress syndrome (ARDS) have shown that: Mechanical ventilation with a tidal volume of 6 mL/kg of predicted body weight is better than mechanical ventilation with a tidal volume of 12 mL/kg of predicted body weight. Prone positioning improves oxygenation but poses safety concerns. A high level of positive end-expiratory pressure does not improve survival. High-frequency oscillatory ventilation is in theory the ideal "lung-protective" method, but its benefits have not been proven. No drug therapy has been shown to improve survival in patients with ARDS. Exogenous surfactant may improve oxygenation but has no significant effect on the death rate or length of use of mechanical ventilation. Low-dose inhaled nitric oxide has no substantial impact on the duration of ventilatory support or on the death rate. Partial liquid ventilation may be beneficial in young patients with acute lung injury or ARDS, although further study is needed to confirm this.

Glycine↗

PubMed1995

Variability in lesion depth on prone and supine CT scans of the chest: implications for the accuracy of transthoracic needle aspiration biopsy.

Transthoracic needle biopsy of the lung is often performed fluoroscopically in the prone position; nodule depth measurements are made from accompanying computed tomographic (CT) scans performed supine. We evaluated the effect of prone and supine positioning on the effect of nodule depth as measured from the skin surface. Twenty consecutive patients having CT-guided biopsy performed in the prone position were assessed. Nodule depth from posterior skin surface to nodule was compared with prebiopsy supine CT scan. Nodules above the carina showed minimal change in depth. Those below the carina showed considerable variability, with depth changes < or = 4.0 cm. Awareness of the magnitude of the potential effect of patient position on lesion depth should be helpful in reducing the likelihood of false negative results in fluoroscopically guided biopsy.

Biopsy, Needle↗

PubMed2006

Dynamic helical CT mammography of breast cancer.

PURPOSE: The purpose of this study was to determine whether dynamic helical computed tomography (CT)-mammography could assist in selecting the most appropriate surgical method in women with breast cancer. MATERIALS AND METHODS: Preoperative contrast-enhanced helical CT scanning of the breast was performed on 133 female patients with suspicion of breast cancer at the same time as clinical, mammographic, and/or ultrasonographic examinations. The patients were scanned in the prone position with a specially designed CT-compatible device. A helical scan was made with rapid intravenous bolus injection (3 ml/s) of 100 ml of iodine contrast material. Three-dimensional maximum intensity projection (MIP) images were reconstructed, and CT findings were correlated with surgical and histopathological findings. RESULTS: Histopathological analysis revealed 84 malignant lesions and seven benign lesions. The sensitivity, specificity, and accuracy levels of the CT scanning were 94.6%, 58.6%, and 78.9%. Helical scanning alone revealed additional contralateral carcinomas in three of four patients and additional ipsilateral carcinomas in three of five patients. However, the technique gave false-positive readings in 24 patients. The preoperative CT-mammogram altered the surgical method in six patients. CONCLUSION: Dynamic helical CT-mammography in the prone position may be one of the choices of adjunct imaging in patients with suspected breast cancer scheduled for surgery.

Adult↗

PubMed1997

Kinematic principles of primate rotational vestibulo-ocular reflex. I. Spatial organization of fast phase velocity axes.

The spatial organization of fast phase velocity vectors of the vestibulo-ocular reflex (VOR) was studied in rhesus monkeys during yaw rotations about an earth-horizontal axis that changed continuously the orientation of the head relative to gravity ("barbecue spit" rotation). In addition to a velocity component parallel to the rotation axis, fast phases also exhibited a velocity component that invariably was oriented along the momentary direction of gravity. As the head rotated through supine and prone positions, torsional components of fast phase velocity axes became prominent. Similarly, as the head rotated through left and right ear-down positions, fast phase velocity axes exhibited prominent vertical components. The larger the speed of head rotation the greater the magnitude of this fast phase component, which was collinear with gravity. The main sequence properties of VOR fast phases were independent of head position. However, peak amplitude as well as peak velocity of fast phases were both modulated as a function of head orientation, exhibiting a minimum in prone position. The results suggest that the fast phases of vestibulo-ocular reflexes not only redirect gaze and reposition the eye in the direction of head motion but also reorient the eye with respect to earth-vertical when the head moves relative to gravity. As further elaborated in the companion paper, the underlying mechanism could be described as a dynamic, gravity-dependent modulation of the coordinates of ocular rotations relative to the head.

Animals↗

PubMed2004

Fatal ischemia stroke in a patient with an asymptomatic carotid artery occlusion after lumbar spine surgery--a case report.

Recognizing carotid artery stenosis (CAS) in an asymptomatic patient preoperatively is difficult. We report a 63-year-old female who had diabetes mellitus and hypertension suffered from a fatal ischemic stroke secondary to a total occlusion of the left carotid artery after a lumbar spine surgery in the prone position. Intraoperative induced hypotension and neck rotation in this patient should be considered as contributory factors. According to previous studies extensively screening out CAS is not recommended. Using electroencephalography (EEG) or somatosensory evoked potential (SSEP) to monitor brain function and carefully positioning of the neck are recommended in these patients who are at risk of stroke while receiving induced hypotension during lumbar spine surgery in the prone position.

Arterial Occlusive Diseases↗

PubMed2000

Spirometry in normal subjects in sitting, prone, and supine positions.

OBJECTIVE: Determine whether pulmonary function testing is affected by patient positioning. METHODS: In a descriptive study with measurements made in a sequential but randomized order at a university-based pulmonary function laboratory, 20 healthy men, ages 18-50 years, were evaluated with spirometric assessment of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and maximum voluntary ventilation (MVV) in the sitting, supine, and prone positions. Subjects were excluded for body mass index (BMI) > 30 kg/m2 or abnormal baseline spirometry. RESULTS: Comparing sitting to supine and prone positions, there was a statistically significant decline in the spirometry values (reported as percent of predicted normal +/- standard error of the mean). FVC was 102% +/- 4% while sitting, 95% +/- 4% while supine, and 94% +/- 4% while prone. FEV1 was 104% +/- 3% while sitting, 96% +/- 3% while supine, and 94% +/- 3% while prone. MVV was 115% +/- 4% while sitting, 102% +/- 4% while supine, and 97% +/- 3% prone. CONCLUSION: In healthy men with BMI < 30 kg/m2, changing from the sitting to supine or prone position results in statistically significant change in respiratory pattern. However, all spirometry values in each position were normal by American Thoracic Society definitions.

Adolescent↗