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At least 19 recordsLinked to original sources

Pneumatosis in the descending colon: preliminary observations on the value of prone positioning.

Prone positioning is valuable for accurate diagnosis of intramural air in the descending colon. In the supine position, partial collapse of the descending colon can minic intramural air. Conversely, complete collapse of the descending colon eliminates the interface between intraluminal and intramural air so that the recognition of intramural air is obscured. The tendency for the descending colon to distend with gas in the prone position may reduce these false positives and negatives for intramural air.

Air

Improved oxygenation and lung compliance with prone positioning of neonates.

Fourteen intubated infants recovering from neonatal respiratory disease had arterial blood gases and lung mechanics measured in the supine position and in two variants of the prone position. Prone positioning resulted in significant increases in mean (+/- SEM) arterial oxygen tension (Pa(o2 70.4 +/- 2.5 to 81.1 +/- 4.4mm Hg), dynamic lung compliance (1.7 +/- 0.24 to 2.55 +/- 0.37 ml/cm H2O),and tidal volume (8.6 +/- 1.0 to 10.5 +/- 1.2 ml) when all prone values were compared to supine values. Prone positioning with the abdomen protruding freely, when compared to all supine values, was associated with significantly increased dynamic lung compliance and tidal volume. Values for prone-abdomen free were not significantly different from values for prone-abdomen restricted. This suggests that there are clinical benefits from prone positioning in neonates recovering from respiratory disease.

Acid-Base Equilibrium

Feasibility of Prone Positioning in Patients With Obesity and Acute Respiratory Distress Syndrome.

BACKGROUND: Prone positioning in patients with obesity remains uncommon because of concerns about feasibility, safety, and efficacy. OBJECTIVE: To evaluate the feasibility, safety, and clinical outcomes of manual prone positioning in patients with acute respiratory distress syndrome (ARDS) across different classes of obesity. METHODS: This was a retrospective cohort study involving patients with ARDS who underwent manual prone positioning across 15 hospitals between April 2014 and July 2024. Patients were stratified into 5 groups based on body mass index. Standardized prone positioning protocols were followed across institutions. RESULTS: A total of 1448 patients with ARDS underwent prone positioning. Across all obesity categories, prone positioning was associated with shorter intensive care unit and hospital stays, improved oxygenation, and better clinical outcomes. Notably, patients with class III obesity showed the greatest increase in gas exchange efficiency, with a 37% improvement in ratio of Pao2 to fraction of inspired oxygen, compared with 28% in patients with normal weight (P < .05). Complication rates were low across all groups. CONCLUSIONS: Prone positioning is feasible and safe in patients with ARDS across all obesity classes. Patients with class III obesity showed the greatest improvements in oxygenation. Future prospective studies should further explore the long-term impact of prone positioning in patients with class III obesity to refine clinical guidelines and optimize care.

Humans

Improved oxygenation with prone positioning in neonates: stability of increased transcutaneous PO2.

To evaluate the effect of body position on oxygenation and ventilation in neonates over a prolonged period, infants with respiratory disease were followed by transcutaneous (tc) monitoring for alterations in tcPO2 and tcPCO2 with position changes. In 14 studies of seven patients, prone positioning was compared with supine positioning over a 6-hour interval. All patients were premature, were receiving supplemental oxygen, and had respiratory disease secondary to prematurity. The median gestational age was 29 weeks; all infants were 2 months old or less at the time of the study. Prone positioning resulted in a significantly higher tcPO2; mean (+/- SD) tcPO2 increased from 63 (+/- 11.6) mm Hg to 71 (+/- 14.6) mm Hg, and decreased to 65 (+/- 11.2) mm Hg when the infant was returned to supine (P less than .05). This increase in tcPO2 was stable throughout 2 hours in the prone position. No significant change in tcPCO2 was detected. Infants were also found to spend a greater proportion of time sleeping when prone (75% +/- 13% vs 33% +/- 14%; P less than .05). These finding suggest that improvement in oxygenation with the prone position is stable over an extended period in the sick preterm infant.

Blood Gas Monitoring, Transcutaneous

The prone position for elbow arthroscopy.

Using the prone position for diagnostic and therapeutic arthroscopy improves intraoperative stability of the arm and allows the surgeon to approach the joint in a more intuitive manner. With this position, indications for elbow arthroscopy are increased and risks to neurovascular structures are reduced. Access to the posterior chamber is facilitated when the patient is in a prone position. This article describes both this arthroscopic technique and portal anatomy.

Arthroscopy

The prone position in ARDS patients. A clinical study.

The gas exchange and hemodynamics were evaluated before, during, and after a two-hour period of prone position in 13 moderate-severe ARDS patients. Lung computerized tomography was obtained in both the supine and prone positions in two of these patients. Average arterial oxygenation improved after prone positioning (p less than 0.01). A PaO2 improvement of at least 10 mm Hg after 30 minutes of prone position was used as a criterion to discriminate between responders and nonresponders to the postural change. Eight patients met the "responders" group criterion, and in the five nonresponder patients, the PaO2 did not change significantly throughout the study. Computerized tomograms in the prone position showed disappearance of posterobasal densities and appearance of new densities in the anterior regions, in both patients studied. One of these was a responder, the other a nonresponder. A brief test period in prone position is indicated in ARDS patients to identify those who may benefit from this postural treatment. The definite mechanism of the arterial oxygenation improvement observed remains to be clarified.

Adult

Hemodynamic effect of the prone position during anesthesia.

We studied 21 patients undergoing lumbar spinal surgery under halothane anesthesia on a convex saddle frame, in order to determine the hemodynamic effect of the prone position. A thermodilution pulmonary arterial catheter was placed in 14 patients (Group PA-1: n = 8; and Group PA-2: n = 6), and an inferior vena caval catheter in the remaining seven patients (Group IVC). Group PA-1 and Group IVC patients were placed in the prone position on a convex saddle frame. In the prone position, the cardiac index (CI) decreased significantly from 3.1 +/- 0.5 to 2.5 +/- 0.3 (l.min-1.m-2, mean +/- s.d., P less than 0.01) without accompanying significant changes in the other hemodynamic variables in Group PA-1. The postural change in Group IVC did not exert a significant effect on the inferior vena caval pressure. Group PA-2 were initially placed in the flat prone position on a flat saddle frame, which produced no significant changes in the hemodynamic variables. Then the convex curvature of the frame was adjusted to the grade appropriate for surgery, which produced a significant reduction in CI (from 2.9 +/- 0.3 to 2.4 +/- 0.4, P less than 0.05). We conclude that the prone position itself may not interfere with the circulatory function. The prone position using a convex saddle frame causes significant reductions in CI, but little change in the other hemodynamic variables.

Anesthesia, Inhalation

Prone positioning in infant gastroesophageal reflux: is elevation of the head worth the trouble?

To determine whether head-elevated prone positioning is better than flat prone positioning for infants with gastroesophageal reflux, we studied 100 babies less than 6 months of age who were being examined for reflux with an intraluminal esophageal pH probe while the babies were in each of the two positions, with the use of a crossover design protocol. During both a 2-hour postprandial period and a fasting period, pH probe measurements in each position included (1) minutes with pH less than 4, (2) number of episodes with pH less than 4, (3) mean duration of such episodes, (4) number of such episodes longer than 5 minutes, and (5) the duration of the longest episode. Significant reductions with head elevation were found for only two of these 10 values: the frequency of reflux episodes postprandially (7.5 +/- 0.7 vs 5.9 +/- 0.5 episodes per 2 hours; p less than 0.05) and the frequency of episodes longer than 5 minutes postprandially (1.4 +/- 0.1 vs 1.2 +/- 0.1 episodes per 2 hours; p less than 0.005). There was no significant reduction in the total duration of postprandial reflux nor in any measure of reflux during the fasting period. The 90 infants in whom an abnormal degree of gastroesophageal reflux was documented had no significant differences between flat prone and head-elevated prone position for any of the 10 pH probe measurements. Head-elevated prone positioning is probably not worth the extra effort required to maintain it.

Esophagus

Pulmonary shunts in the prone position.

Pulmonary shunting (Qs/Qt with the FIO2 = 1) was determined in ten young healthy non-obese patients prior to anaesthesia, 30 min after induction in the supine position and 1 h later during surgery in the prone position. Respiration was spontaneous in awake patients and was controlled following the induction of anaesthesia. Halothane was the primary anaesthetic and tubocurarine provided muscle relaxation. Mean PaCO2 was 40.7, 29.5 and 27.9 mmHg respectively in the three study periods. The shunt remained unchanged at 5.7 +/- 0.8% in the awake patients, and 6.0 +/- 1.1% during anaesthesia in the supine position, and 5.2 +/- 1.2% during anesthesia and surgery in the prone position. It is concluded that in this population the prone position does not alter the magnitude of the pulmonary shunt even in those patients who develop shunts of over 10% after the induction of anaesthesia.

Adult

Significance of prone positioning in planning treatment for esophageal cancer.

The treatment of esophageal cancer is made difficult by the close proximity of the esophagus to the spinal cord and the requirement to treat the esophageal target volume to doses greater than or equal to 60 Gy while limiting the spinal cord dose to less than or equal to 46 Gy. By placing the patient in the prone position, the esophagus can be displaced away from the spinal cord. We explored the results of this commonly used technique on 16 patients who have undergone simulation in both supine and prone positions. Both AP and lateral orthogonal radiographs were obtained in both positions. The distance between contrast material in the esophagus and spinal cord was noted in at least four transverse planes through the thoracic esophagus on each of the 16 patients. These four transverse planes were located at 3 cm above the carina, at the carina, 3 cm below the carina and 6 cm below the carina. The mean displacement (+/- 1 SD) of the esophagus away from the spinal cord when the patient was in the prone position compared to supine at each of these levels was 1.3 (+/- 0.8) cm, 1.8 (+/- 0.9) cm, 1.8 (+/- 1.0) cm, and 1.9 (+/- 1.1) cm. The range of displacement for all 64 displacement determinations was 0 to 4.2 cm with a mean of 1.7 cm. To evaluate further the consequences of prone positioning on treatment planning and doses received to target volumes and critical structures, we performed 3-dimensional treatment planning with a patient in both prone and supine positions. The requirements were to achieve a tumor volume dose of 60 Gy while keeping the spinal cord dose below 46 Gy. Two types of conventional treatment plans were examined in prone and supine positions. A 6-field plan consisted of delivery of 40 Gy through a large 3-field beam arrangement followed by delivery of 20 Gy through a similar 3-field cone down. An 8-field plan involved the delivery of 30 Gy through AP/PA beams followed by a 3-field beam arrangement to 40 Gy and a subsequent 3-field cone-down for the final 20 Gy. Comparison of dose volume histograms revealed that the 6-field plan spared relatively more heart whereas the 8-field plan spared relatively more lung. Regarding the primary consideration of coverage of target volume with avoidance of spinal cord, prone positioning was superior to supine positioning whether 6- or 8-field arrangements were used.

Esophageal Neoplasms

The lateral extracavitary approach to the spine using the three-quarter prone position.

A three-quarter prone position for the lateral extracavitary operative approach to the thoracic and lumbar spine is described. This approach has been used in 40 patients with anterior spinal cord compressive lesions in the thoracic and/or lumbar region. In this patient population, it has allowed a safe ventral decompression of the spinal cord. It also allows placement of spinal instrumentation through the same incision. Both the operating surgeon and the assistant have an excellent view of the operative site, including the dural sac. Patient positioning and the operative approach are described and illustrated.

Brachial Plexus

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

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

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

[Respiratory care with prone position for diffuse atelectasis in critically ill patients].

Diffuse atelectasis often occurs in the dorsal region of the lung of critically ill patients under long term mechanical ventilation. Conventional physical therapies (ex. PEEP, Sigh) have little effect on diffuse dorsal atelectasis. We provided respiratory care with prone position for 7 patients with severe respiratory distress (Two patients were treated twice). Improvement of their Respiratory Indexes (RI, mean 2.97) was obtained in the prone position for 6-163 (mean 35.8) hours. Ventilation efficiency also improved. Static lung compliance didn't change. It was assumed that the prone position was the factor responsible for the improvement of pulmonary V/Q ratio, the change of movement pattern of the diaphragm, and the ease of postural drainage of sputum. There were no complications. We conclude that prone position respiratory care has high utility for critically ill patients with diffuse dorsal atelectasis.

Adult

Extracorporeal shock wave lithotripsy in the prone position for stones situated anteriorly.

Stones situated anteriorly cannot be satisfactorily reached with extracorporeal shock wave lithotripsy (ESWL) in the supine position. By assuming the prone position, patients with stones in horseshoe or ectopic kidneys or in the iliac ureter can be treated by ESWL with the same success rate as patients with posterior stones. This new technique has been used in 30 patients with iliac ureteral stones, 5 patients with caliceal stones in horseshoe kidneys and 1 patient with a pyelic stone in a sacral kidney.

Adult

[The prone position as an indicator of deviated motor development during the first year of life].

The adequate control and alignment of a baby in the prone position during the first year of life is a basic necessary milestone for a normal, neuromotor development. In this study the prone position was registered in 246 babies with a previous pediatric evaluation, three options could be made: normal retarded or altered. The Milani Comparetti neuromotor evaluation was also realized for each baby at the same time with the same classification options. Both results were compared. A sensitivity and specificity = 1.0 were found for the prone position registered. This test is fast and simple, so it is recommended at a first attention level in high risk population for neuromotor disability.

Age Factors

Improved oxygenation in patients with acute respiratory failure: the prone position.

To assess the potential benefits of the prone position for gas exchange in patients with acute respiratory failure, we turned 6 patients from supine to prone, supporting the upper thorax and pelvis and allowing the abdomen to protrude. Arterial PO2 increased by a mean of 69 mm Hg (range, 2 to 178 mm Hg) at the same tidal volume, same inspired oxygen concentration, and same level of positive end-expiratory pressure. The maneuver made it possible to reduce the inspired oxygen concentration in 4 of the 5 patients who required mechanical ventilation of the lungs and to defer intubation in the patient who was breathing spontaneously. After subsequent turns from supine to prone, arterial PO2 increased by a mean of 35 mm Hg (range, 4 to 110 mm Hg), permitting a decrease in inspired oxygen concentration or positive end-expiratory pressure when prone (4 patients); arterial PO2 decreased in 12 of 14 instances after the patient was turned from prone to supine. No significant change in mean arterial carbon dioxide tension, respiratory frequency, or effective compliance was observed.

Acute Disease