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PubMed1998

Prone position may increase temperature around the head of the infant.

Recommendations to adopt the supine position were followed by a dramatic decrease of SIDS. But no explanation has been given for the association between SIDS and the prone position nor for its decrease in the supine position. We report data on an infant and a mannequin demonstrating an increase in temperature around the head in the prone position. A 4-month-old boy presented an acute life-threatening event related to temperature after febrile otitis despite treatment: 40.5 degrees C, heart rate 280 bpm with circulatory failure and cardiorespiratory arrest requiring resuscitation. There were no seizures. Blood and CSF cultures were negative. The course under antibiotics was favourable. On d 3, we measured temperature at several sites on and around the heat. Temperatures were higher in the prone than in the supine position in pericephalic areas: +1 degrees C (supracephalic), +2.5 degrees C (peritemporal), and +3.5 degrees C (submandibular). In a thermoregulated room, we used a mechanically ventilated mannequin of an infant. The prone position was also associated with an increase in temperature around the head: +3.3 degrees C (supracephalic), +1.8 degrees C (peritemporal), and +1.1 degrees C (submandibular). Changing from the supine to prone position thus increased temperature around the head (infant and mannequin). To our knowledge, this has not been reported before. SIDS is related to factors modifying temperature status and environment. Furthermore, evacuation of heat is mandatory for an infant. We think the increase in temperature around the head in the prone position is due to the absence of convective fluxes, and speculate it could impair thermolysis.

Body Temperature↗

PubMed2006

Initial experience with video-assisted thoracoscopic surgery for pulmonary metastasis in the prone position.

We performed video-assisted thoracoscopic surgery for pulmonary metastasis with the patient in the prone position because the use of the full lateral decubitus position was not possible owing to a deformity of the upper extremity, which existed because of a previous operation for osteosarcoma. In cases where the lateral decubitus position cannot be used, the prone position is both safe and effective for treating dorsal lesions of the lung by means of video-assisted thoracoscopic surgery.

Adult↗

PubMed2006

Robot-assisted thoracoscopic esophagectomy with the patient in the prone position.

We describe a new technique of esophagectomy by robot-assisted thoracoscopy with the patient in the prone position, followed by laparoscopy and left cervicotomy with the patient in the supine position. We report two procedures performed November 2002 and September 2003. The technique should allow more thorough lymph node removal while reducing postoperative pain and morbidity. The thoracoscopy is robot-assisted and the articulations within the pleural cavity improve the surgeon's dexterity and reduce trocar movements. The prone position allows mobilization of the esophagus with only three trocars because the lung, which is partially deflated, does not block access. With the patient in the prone position, bleeding does not obscure the operative field. Stomach mobilization, gastric tube creation, and celiac lymphadenectomy are performed by laparoscopy. The esogastric anastomosis is a totally mechanical side-to-side anastomosis realized by left cervicotomy.

Carcinoma, Squamous Cell↗

PubMed2005

Prone position in mechanically ventilated patients -- the hard or the soft way?

Prone positioning may even in patients without abdominal hypertension result in an increased intra-abdominal pressure (IAP). Previous research could not demonstrate a marked increase in IAP associated with cardiovascular, renal, or hepato-splanchnic dysfunction when patients were proned in air-cushioned beds. Michelet and colleagues in this issue of Critical Care report that the increase in IAP in the prone position depends on the used mattress type. Compared with air-cushion beds, conventional foam mattresses resulted in a greater increase in IAP which was associated with a decrease in the plasma disappearance rate of indocyanin green (PDRICG) indicating inadequate heptosplanchnic function.

Animals↗

PubMed2006

Ischemic orbital compartment syndrome as a complication of spinal surgery in the prone position.

OBJECTIVES: To report a patient with ischemic orbital compartment syndrome as a complication of spinal surgery in the prone position. DESIGN: Interventional case report. METHODS: An 80-year-old man underwent a prolonged lumbar decompression laminectomy for spinal stenosis, under general anesthesia in the prone position. Several hours later, the patient complained of left periocular pain and reduced vision. Examination revealed significant facial edema, left proptosis, and a tight orbit, as well as no light perception and elevated intraocular pressure in the left eye, with complete internal and external ophthalmoplegia. MAIN OUTCOME MEASURES: Clinical course, imaging findings, management, and final outcome. RESULTS: Magnetic resonance imaging confirmed the clinical diagnosis of a compartment syndrome with elevated intraorbital tension. A lateral canthotomy and cantholysis were performed, and high-dose IV steroids were started. The proptosis and facial swelling subsided gradually, but no improvement was noted in left visual acuity or left ocular movements. CONCLUSION: It is important to be familiar with this rare complication after prolonged surgery in the prone position. Although the prognosis seems to be poor, it is essential to monitor these patients perioperatively and to intervene surgically and medically once the diagnosis of orbital compartment syndrome is established.

Acetazolamide↗

PubMed1999

CT colonography: value of scanning in both the supine and prone positions.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of CT colonography when patients were imaged in both the supine and prone positions. We evaluated whether imaging in two positions decreased the number of collapsed colonic segments and increased sensitivity for polyp detection. MATERIALS AND METHODS: Twenty-three patients underwent CT colonography in both the supine and prone positions. Colonic distention for each of the 46 scans was graded. Adequacy of distention for either position alone was compared with that of the combination of the two positions. Polyp data revealed by colonoscopy were reviewed, and the CT data were then retrospectively reviewed for polyp detection. RESULTS: When each scan was considered alone without benefit of the scan obtained in the opposite position, 27 (58.7%) of 46 scans showed inadequate distention. When scans obtained in both positions were considered together, 20 (87.0%) of 23 patients had adequate distention with the grading system used. However, this value increased to 23 (100%) of 23 patients when the reasons for inadequate distention in the three patients were considered. Of the 27 polyps detected with colonoscopy, 21 (77.8%) were also detected retrospectively with CT colonography. Colonoscopy showed 20 polyps that were 5 mm or larger; nineteen (95.0%) of these 20 polyps were also detected retrospectively with CT colonography, nine (47.4%) of which were seen in only one position. CONCLUSION: Use of both the supine and prone positions for patients undergoing CT colonography improves evaluation of the colon and increases sensitivity for polyp detection.

Aged↗

PubMed2004

Prone positioning in the patient who has acute respiratory distress syndrome: the art and science.

Acute respiratory distress syndrome (ARDS) remains a significant contributor to the morbidity and mortality of patients in the ICU. A variety of treatments are used to support the lung of the patient who has ARDS and improve gas exchange during the acute injury phase. It seems, however, that the simple, safe, and noninvasive act of prone positioning of the critically ill patient who has ARDS may improve gas exchange while preventing potential complications of high positive end-expiratory pressure, volutrauma, and oxygen toxicity. This article provides the critical care nurse with the physiologic rationale for use of the prone position, indications and contraindications for use, safe strategies for prone positioning, and care techniques and monitoring methods of the patient who is in the prone position.

Critical Care↗

PubMed1997

Laparoscopic-assisted abdominoperineal resection in the prone position. An alternative technique.

With the introduction of laparoscopic-assisted abdominoperineal resection (LAPR), the traditional Lloyd-Davies position with the Mayo two-team combined approach is being adapted. The Lloyd-Davies position allows two teams of surgeons to work simultaneously, minimizing operating time. The conditions required for laparoscopy restrict a simultaneous procedure. Since LAPR is typically performed as a two-stage procedure, we introduce an alternative position which facilitates the perineal dissection. We review the results and technique of LAPR in the prone position in three patients who were suitable candidates for this procedure. Three patients underwent LAPR. No operative or postoperative complications were encountered and the procedures were in keeping with oncologic principles of resection. Total anesthesia times were less than 3.5 h for these initial patients. No hemodynamic problems were encountered due to the choice of patient positioning. The prone jackknife position greatly increases visualization of deep structures, reduces blood loss, enhances dissection, and reduces the technical demands of the laparoscopic portion of the procedure.

Abdomen↗

PubMed1996

The effect of four different surgical prone positions on cardiovascular parameters in healthy volunteers.

Twenty healthy volunteers were placed in four different surgical prone positions: on pillows, on an evacuatable mattress, on pelvic props and in the knee-chest position. The normal supine position was used as a control for the measurement of cardiovascular parameters. Mean arterial pressure was measured by automated oscillotonometry. Transthoracic electrical bioimpedance was used to measure cardiac output and heart rate. Cardiac index and total vascular resistance index were derived from these data. No significant changes in heart rate or mean arterial pressure occurred when the volunteers were moved from the supine position to any of the four prone positions or when returned to the supine position again. Cardiac index decreased significantly on going from the supine to the knee-chest position (20%) and onto the props (17%) but not onto the evacuatable mattress (11%) or the pillows (3%).

Adult↗

PubMed1989

Vacuum-stiffened beanbag for cranial remodeling procedures in modified prone position. Technical note.

In surgical correction of multiple-suture synostosis, placing the patient in the modified prone position permits access to the calvarium from the supraorbital ridge to the occipital bone below the transverse sinus. The modified prone position thereby enables surgeons to perform cranial remodeling procedures at one stage under direct vision, contributing to improved surgical results. However, no satisfactory head-frame for this position has been available. The authors report the successful use of a vinyl bag filled with styrofoam beads to achieve the modified prone position in young children. This widely available, economical device provides a safe, reliable means of positioning the child's head for cranial remodeling procedures.

Child, Preschool↗

PubMed1990

Prone position reverses gravitational distribution of perfusion in dog lungs with oleic acid-induced injury.

Although oxygenation improves in patients with the adult respiratory distress syndrome and in animals with oleic acid- (OA) induced acute lung injury when they are turned from the supine to the prone position, the mechanism(s) by which this improvement occurs is not known. Several groups have speculated that this improvement results from preferential edema accumulation in the dorsal lung regions and redistribution of perfusion away from these regions when the patients are turned to the prone position. We used radiolabeled microspheres to measure the regional distribution of perfusion (Qr) to the dorsal, mid, and ventral lungs of eight dogs in vivo in the supine and prone positions, before and after inducing acute lung injury with OA, and correlated the Qr observed after injury with the degree of regional extravascular lung water (EVLWr). Before OA, Qr increased along the gravitational gradient when the animals were supine but was more uniformly distributed when they were prone. After OA, Qr again followed a gravitational gradient when the animals were supine but was preferentially distributed to the nondependent regions when they were prone. EVLWr was similar in all regions, regardless of whether OA was injected when the animals were supine or prone. The gravitational Qr gradient is markedly reduced in the prone position, both before and after lung injury. The prone position-induced improvement in oxygenation is not the result of redistribution of Qr away from areas in which edema preferentially develops.

Animals↗

PubMed1997

Short-term effects of prone position in critically ill patients with acute respiratory distress syndrome.

OBJECTIVE: Changing the position from supine to prone is an emerging strategy to improve gas exchange in patients with the acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate the acute effects on gas exchange, hemodynamics, and respiratory system mechanics of turning critically ill patients with ARDS from supine to prone. DESIGN: Open, prospective study. SETTING: General intensive care units. PATIENTS: 23 patients [mean age 56 +/- 17 (SD) years] who met ARDS criteria and had a Lung Injury Score > 2.5 (mean 3.25 +/- 0.3). INTERVENTIONS: The decision to turn a patient was made using a protocol based on impaired oxygenation despite the use of positive end-expiratory pressure and a fractional inspired oxygen (FIO2) of 1. MEASUREMENTS AND RESULTS: We measured gas exchange and hemodynamic variables in all patients and in 16 patients calculated respiratory system compliance when they were supine and 60 to 90 min after turning them to a prone position. This latter position was remarkably well tolerated and no clinically relevant complications or events were detected either during turning or while prone. The partial pressure of oxygen in arterial blood (PaO2)/FIO2 ratio improved from 78 +/- 37 mm Hg supine to 115 +/- 31 mm Hg prone (p < 0.001), and intrapulmonary shunt decreased from 43 +/- 11 to 34 +/- 8% (p < 0.001). Cardiac output and other hemodynamic parameters were not affected. Respiratory system compliance slightly improved from 24.7 +/- 10.2 ml/cmH20 supine to 27.8 +/- 13.2 ml/cmH20 prone (p < 0.05). An improvement in PaO2/FIO2 of more than 15% from changing from supine to prone was found in 16 patients (responders). Responders had more hypoxemia (PaO2/FIO2 70 +/- 23 vs 99 +/- 53 mm Hg in non-responders, p < 0.01), more hypercapnia (partial pressure of carbon dioxide in arterial blood (70 +/- 27 vs 64 +/- 9 mm Hg, p < 0.01) and a shorter elapsed time to the onset of ARDS and turning to the prone position (11.8 +/- 16 vs 32.8 +/- 42 days, p < 0.01). CONCLUSIONS: Turning critically ill, severely hypoxemic patients from the supine to the prone position is a safe and useful therapeutic intervention. Our data suggest that prone positioning should be carried out early in the course of ARDS.

Adult↗

PubMed1999

Right-to-left interatrial shunt in ARDS: dramatic improvement in prone position.

The mechanisms leading to shunting through a patent foramen ovale include high right-sided cardiac pressures and respiratory factors due to mechanical ventilation and also anatomical changes in the right atrium as described in the platypnea-orthodeoxia syndrome. We report a patient with the adult respiratory distress syndrome (ARDS) who had a right-to-left atrial shunt which decreased in the prone position, after which oxygenation improved. The patient was admitted to the intensive care unit because of ARDS due to an invasive fungal infection. He had a history of chronic lymphocytic leukemia and paradoxical embolisms through a patent foramen ovale. Despite mechanical ventilation and antifungal treatment he developed severe ARDS. He was therefore turned to the prone position. Blood gas values improved dramatically (arterial oxygen tension/fractional inspired oxygen ratio increasing from 59 to 278 torr). Transcranial Doppler sonography was performed with bubble study, which confirmed a massive right-to-left shunt in the supine position and which instantaneously decreased in the prone position. This case suggests that a decrease in right-to-left shunt in patients who have a patent foramen ovale could partly explain the improvement in hypoxemia in the prone position.

Aged↗

PubMed1999

Use of the prone position in the management of acute respiratory distress syndrome.

The positioning of patients is usually within the domain of nursing practice, whether this is to achieve increased comfort or as a therapeutic intervention to avoid the occurrence of pressure sores. The use of the prone position to improve oxygenation, in the acute respiratory distress syndrome, has become increasingly popular in intensive care over the past decade (Thomas 1997). A systematic review was, therefore, undertaken to ascertain if the prone position did, in fact, improve oxygenation, leading to decreased mortality, or if the effects were merely transitory. Review findings indicate that use of the prone position does improve oxygenation, as measured by PaO2/FiO2 indices, and appears to reduce mortality. However, caution should be taken in applying these results to practice. First, the studies available for review demonstrated various methodological flaws. It is also apparent that untoward incidences associated with the prone position have yet to be investigated systematically.

Bias↗

PubMed1996

Use of the prone position in the MRI evaluation of spinal cord retethering.

In order to determine the impact of magnetic resonance imaging (MRI) in the management of spinal cord retethering, we retrospectively reviewed case and imaging records of 51 patients who underwent MRI examination in supine and prone positions. Group 1 included 8 control patients without cord tethering. They exhibited a normal level of the conus medullaris with normal surrounding subarachnoid space, and consistent anterior migration of the conus within the dural sac on MRI in prone position. Group 2 included 17 patients with tethered cord secondary to occult spinal dysraphism (spinal cord lipoma in 6 patients, thick filum terminale in 4, diastematomyelia in 4, myelomeningocele manqué in 2, and dermoid tumour in 1). Supine and prone MRI performed at a median period of time of 6 months after untethering showed resolution of posterior tethering in 5 out of the 7 patients who exhibited pre-operatively dorsal attachment of the spinal cord to the dura. Anterior migration of the conus or of the cord/filum complex in prone position was observed in only 24% of the cases. Group 3 included 26 patients with secondary tethered cord following prior myelomeningocele closure. Their MRI performed at a median interval of time of 11 months following untethering demonstrated resolution of the posterior cord tethering in only 8 out of the 24 patients who exhibited this feature pre-operatively. Anterior migration within the expanded dural sac was never noted in this group. We conclude that spine MRI is of limited value and that prone-positioned MRI is of no additional use in the evaluation of spinal cord retethering.

Adolescent↗

PubMed2006

Effects of prone position on alveolar dead space and gas exchange during general anaesthesia in surgery of long duration.

BACKGROUND AND OBJECTIVE: We investigated the effects of prone position on respiratory dead space and gas exchange in 14 anaesthetized healthy patients undergoing elective posterior spinal surgery of more than 3 h of duration. METHODS: The patients received a total intravenous anaesthetic with propofol/remifentanil/cisatracurium. They were ventilated at a tidal volume of 8-10 mL kg(-1), zero positive end-expiratory pressure and an inspired oxygen fraction of 0.4. Physiological, airway and alveolar dead spaces were calculated by analysis of the volumetric capnography waveform. Measurements were made in supine position (20 min after the beginning of mechanical ventilation) and 30, 120 and 180 min after turning to prone position. RESULTS: We found that the alveolar dead space/tidal volume ratio did not change. PaO(2)/F(i)O(2) increased, although not statistically significantly. Dynamic compliance was reduced due to a reduction in tidal volume and an increase in plateau pressure. CONCLUSIONS: Patients undergoing surgery in prone position for a duration of 3 h under general anaesthesia including muscle relaxation and mechanical ventilation without positive end-expiratory pressure have stable haemodynamics and no significant changes in the alveolar dead space to tidal volume ratio. Oxygenation tended to improve.

Anesthesia, General↗

PubMed1979

Effect of supine and prone positions on arterial oxygen tension in the preterm infant.

To determine the optimal position for the preterm infant, arterial oxygen tension (Pao2) was monitored in 16 preterm infants by the transcutaneous method with the infants in both supine and prone positions. When the infants were prone, Pao2 rose by a mean of 7.4 mm Hg (P less than .001), an increase of 15%. In those infants with residual cardiopulmonary disease a 25% increase was noted. The higher Pao2 in the prone position was accompanied by a significant decrease in the amount of time the chest wall moved asynchronously. This improved oxygenation in the prone position appears to be the result of enhanced ventilation/perfusion ratios and not merely secondary to an alteration in sleep state with positioning of the infant. These findings may have important implications in the management of preterm infants, requiring neonatal intensive care.

Arteries↗

PubMed2005

Prone positioning improves oxygenation in post-traumatic lung injury--a prospective randomized trial.

BACKGROUND: In a prospective randomized trial the effect of prone positioning on the duration of mechanical ventilation was evaluated in multiple trauma patients and was compared with patients ventilated in supine position. METHOD: Multiple trauma patients of the intensive care units of two university hospitals were considered eligible if they met the criteria for acute lung injury or the acute respiratory distress syndrome. Patients in the prone group (N = 21) were kept prone for at least eight hours and a maximum of 23 hours per day. Prone positioning was continued until a PaO2:FiO2 ratio of more than 300 was present in prone as well as supine position over a period of 48 hours. Patients in the supine group (N = 19) were positioned according to standard care guidelines. RESULTS: The duration of ventilatory support did not differ significantly (30 +/- 17 days in the prone group and 33 +/- 23 days in the supine group). Worst case analysis (death and deterioration of gas exchange) displayed ventilatory support for 41 +/- 29 days in the prone group and 61 +/- 35 days in the supine group (p = 0.06). The PaO2:FiO2 ratio increased significantly more in the prone group in the first four days (p = 0.03). The prevalence of Acute Respiratory Distress Syndrome (ARDS) following acute lung injury (p = 0.03) and the prevalence of pneumonia (p = 0.048) were reduced also. One patient in the prone and three patients in the supine group died due to multi organ failure (p = 0.27). CONCLUSIONS: Intermittent prone positioning was not able to reduce the duration of mechanical ventilation in this limited number of patients. However the oxygenation improved significantly over the first four days of treatment, and the prevalence of ARDS and pneumonia were reduced.

Adult↗