Effect of prone positioning on clinical outcomes in children with acute lung injury: a randomized controlled trial. Decreased activity and oxygen desaturation in prone ventilated preterm infants during the first postnatal week. Effect of positioning on the breathing pattern of preterm infants. High-frequency oscillatory ventilation following prone positioning prevents a further impairment in oxygenation. 4A randomized trial of prolonged prone positioning in children with acute respiratory failure. The effect of body position on the respiratory rate of infants with tachypnea. Effects of body position on blood gases and lung mechanics of infants with chronic lung disease during tube feeding. [Effect of preterm infant position on weaning from mechanical ventilation]. Effect of position on the mechanical interaction between the rib cage and abdomen in preterm infants.
In uncontrolled clinical studies, prone positioning appeared to be safe and to improve oxygenation in pediatric patients with acute lung injury. However, the effect of prone positioning on clinical outcomes in children is not known.
                To test the hypothesis that at the end of 28 days infants and children with acute lung injury treated with prone positioning would have more ventilator-free days than those treated with supine positioning.
                Multicenter, randomized, controlled clinical trial conducted from August 28, 2001, to April 23, 2004, of 102 pediatric patients from 7 US pediatric intensive care units aged 2 weeks to 18 years who were treated with supine vs prone positioning. Randomization was concealed and group assignment was not blinded.
                Patients were randomized to either supine or prone positioning within 48 hours of meeting acute lung injury criteria, with those patients in the prone group being positioned within 4 hours of randomization and remaining prone for 20 hours each day during the acute phase of their illness for a maximum of 7 days, after which they were positioned supine. Both groups were treated using lung protective ventilator and sedation protocols, extubation readiness testing, and hemodynamic, nutrition, and skin care guidelines.
                Ventilator-free days to day 28.
                The trial was stopped at the planned interim analysis on the basis of the prespecified futility stopping rule. There were no differences in the number of ventilator-free days between the 2 groups (mean [SD], 15.8 [8.5] supine vs 15.6 [8.6] prone; mean difference, -0.2 days; 95% CI, -3.6 to 3.2; P = .91). After controlling for age, Pediatric Risk of Mortality III score, direct vs indirect acute lung injury, and mode of mechanical ventilation at enrollment, the adjusted difference in ventilator-free days was 0.3 days (95% CI, -3.0 to 3.5; P = .87). There were no differences in the secondary end points, including proportion alive and ventilator-free on day 28 (P = .45), mortality from all causes (P>.99), the time to recovery of lung injury (P = .78), organ-failure-free days (P = .88), and cognitive impairment (P = .16) or overall functional health (P = .12) at hospital discharge or on day 28.
                Prone positioning does not significantly reduce ventilator-free days or improve other clinical outcomes in pediatric patients with acute lung injury. To compare the effects of supine and prone positions on oxygen saturation (SpO(2)), desaturation episodes (SpO(2) < 90% and >or= 20 seconds), and motor activity in ventilated preterm infants during their first postnatal week.
                With use of a crossover design, we randomly assigned infants to a supine/prone or prone/supine position sequence. Infants were placed in each position for 2 hours. A stabilization period of 10 minutes before observation of each position was allowed. During the protocol, care procedures were kept minimal and ventilator settings remained unchanged.
                Neonatal intensive care units at 2 tertiary care centers in Taiwan.
                The sample consisted of 28 infants receiving mechanical ventilation who were 25 to 36 weeks' gestation, without known congenital abnormalities, within 7 postnatal days of birth, and were not receiving sedation.
                When prone, infants had higher SpO(2), fewer episodes of oxygen desaturation, and less motor activity than when supine. No significant differences in duration of SpO(2) less than 90%, 85%, and 80% were found between the 2 positions. Seventy-four percent of desaturation episodes were associated with vigorous motor activity and crying.
                The prone position results in less motor activity and may stabilize oxygenation for ventilated preterm infants. This may conserve energy and decrease complications of hypoxia for sick preterm infants. Respiration, as judged by gas exchange and pulmonary function, is improved in preterm infants kept in the prone rather than the supine position. The influence of position on the breathing pattern as documented by the pneumogram was studied in 14 stable preterm infants with recent clinical apnoea. Ten of the infants had oximetry and nasal flow studies simultaneously with the impedance pneumogram. Each infant had consecutive nocturnal pneumograms, one in the prone, one in the supine position. The infants were kept for more than six hours in the assigned position. A significant increase in apnoea density and in periodic breathing was found in the supine v the prone position (mean (SE) 4.5 (0.7)% v 2.5 (0.5)%, and 13.6 (3.2)% v 7.7 (2.2)%, respectively). There was no positional difference in the incidence of bradycardia and prolonged apnoea. The examination of obstructive apnoea, mixed apnoea, and cyanotic spells did not reveal a consistent disparity between the two positions. These findings indicate an increase in central apnoea in preterm infants kept predominantly in the supine position. Possible relations of positional changes to lung mechanics are discussed. When evaluating pneumograms, attention must be given to the position in which they were performed. The improvement in oxygenation with prone positioning is not persistent when patients with acute respiratory distress syndrome (ARDS) are turned supine. High-frequency oscillatory ventilation (HFOV) aims to maintain an open lung volume by the application of a constant mean airway pressure. The aim of this study was to show that HFOV is able to prevent the impairment in oxygenation when ARDS patients are turned back from the prone to the supine position.
                Prospective, comparative randomized study.
                A medical intensive care unit.
                Forty-three ARDS patients with a Pao2/Fio2 ratio <150 at positive end-expiratory pressure > or =5 cm H2O.
                After an optimization period, the patients were assigned to one of three groups: a) conventional lung-protective mechanical ventilation in the prone position (12 hrs) followed by a 12-hr period of conventional lung-protective mechanical ventilation in the supine position (CV(prone)-CV(supine)); b) conventional lung-protective mechanical ventilation in the supine position (12 hrs) followed by HFOV in the supine position (12 hrs) (CV(supine)-HFOV(supine)); or c) conventional lung-protective mechanical ventilation in the prone position (12 hrs) followed by HFOV in the supine position (CV(prone)-HFOV(supine) group).
                Pao2/Fio2 ratio was higher at the end of the study period in the CV(prone)-HFOV(supine) group than in the CV(prone)-CV(supine) group (p < .02). Venous admixture at the end of the study period was lower in the CV(prone)-HFOV(supine) group than in the two other groups.
                HFOV maintained the improvement in oxygenation related to prone positioning when ARDS patients were returned to the supine position. To compare the effect of the prone position (PP) vs supine position (SP) on oxygenation in children with acute respiratory failure (ARF).
                Prospective, randomized controlled trial.
                A 36-bed pediatric critical-care unit in a tertiary-care, university-based children's hospital.
                Ten children (mean [SD] age, 5 +/- 3.6 years) with ARF with a baseline oxygenation index (OI) of 22 +/- 8.5.
                Following a period of stabilization in the SP, baseline data were collected and patients were randomized to one of two groups in a two-crossover study design: group 1, supine/prone sequence; group 2, prone/supine sequence. Each position was maintained for 12 h. Lung mechanics and acute response to inhaled nitric oxide were examined in each position.
                OI was significantly better in the PP compared to the SP over the 12-h period (analysis of variance, p = 0.0016). When patients were prone, a significant improvement in OI was detected (7.9 +/- 5.3; p = 0.002); this improvement occurred early (within 2 h in 9 of 10 patients) and was sustained over the 12-h study period. Static respiratory system compliance and resistance were not significantly affected by the position change. Inhaled nitric oxide had no effect on oxygenation in either position. Urine output increased while prone, resulting in a significantly improved fluid balance (+ 6.6 +/- 15.2 mL/kg/12 h in PP vs + 18.9 +/- 13.6 mL/kg/12 h in SP; p = 0.041). No serious adverse effects were detected in the PP.
                In children with ARF, oxygenation is significantly superior in the PP than in the SP. This improvement occurs early, remains sustained for a 12-h period, and is independent of changes in lung mechanics. In neonatal disease states where lung compliance is reduced (e.g., inadequate resorption of fetal lung fluid or, surfactant deficiency) an infant's normally low functional residual capacity (FRC) decreases even further. Tachypnea is an efficient compensatory maneuver for the newborn. We evaluated the effect of different bed and body positions on the increased respiratory rate observed in infants with transient tachypnea of the newborn (TTN), infant respiratory distress syndrome (RDS), and bronchopulmonary dysplasia (BPD). Seventeen infants were studied (TTN, n = 6; RDS, n = 6; BPD, n = 5) in four different positions: supine flat, supine elevated, prone flat, and prone elevated. Respiratory rate and heart rate were evaluated in each position. Analysis of variance for the three patient groups showed a lower respiratory rate when the bed was elevated 20-30 degrees compared to flat (P = 0.0001), in the prone posture compared to supine (P = 0.031), and no significant difference in heart rate. The lowest mean respiratory rate occurred when patients were in the prone elevated position. The significant improvement in tachypnea seen in the prone and elevated positions was likely related to improved FRC resulting from reduced cephalad stress on the diaphragm from the abdomen. Positioning neonatal patients with respiratory insufficiency was a simple and safe therapeutic maneuver with prompt and demonstrable benefit. The effects of body position and feeding on lung mechanics and blood gases in very low birthweight infants with chronic lung disease (CLD) is not fully elucidated.
                Seven very low birthweight infants who were being mechanically ventilated because of CLD were examined. They were enrolled in this study when their feeding volume exceeded 100 mL/kg per day. Each patient was kept on the same position (either prone or supine) during feeding. Feeding was given by a nasogastric tube for over 1 h every 3 h. Blood gases and lung mechanics were evaluated before, 20 min and 40 min after the initiation of the feeding and at the end of the feeding.
                The prone position resulted in a significant increase in arterial oxygen saturation during feeding. The tidal volume in the prone position was significantly larger than in the supine position only before feeding. There were no significant differences in minute ventilation between these positions during the study. Pulmonary resistance was not different in either position, but the static compliance and the work of breathing of spontaneous breaths were improved significantly when the infants were in the prone position. In the supine position, work of breathing increased and static compliance decreased significantly with time, while in the prone position, those values did not change significantly.
                The improvement in lung mechanics may partly explain better oxygenation obtained in the prone position. The prone position could decrease energy expenditure for spontaneous breathing and may shorten the period of ventilatory support for very low birthweight infants with CLD. To determine the effects of prone positioning on cardiorespiratory stability and weaning outcome of preterm infants during weaning from mechanical ventilation.
                From January to December 1999, a sample of 42 preterm infants, with birthweight < 2,000 g, mechanically ventilated in the first week of life, were randomly divided, in the beginning of the weaning process, into two groups according to the position: supine position (n = 21) or prone position (n = 21). Heart rate, respiratory rate, transcutaneous oxygen saturation and ventilatory parameters were recorded every one hour. Length of the weaning process and complications were also assessed.
                In both groups the mean gestational age was 29 weeks, most of the patients presented very low birthweight and respiratory distress syndrome. The mean length of the weaning process was 2 days. There were no differences between the groups regarding respiratory rate, heart rate and transcutaneous oxygen saturation, however, oxygen desaturation episodes were more frequent in supine position (p = 0.009). Ventilatory parameters decreased faster and reintubation was less frequent in the prone group (4% versus 33%). No adverse effects of prone positioning were observed.
                These results suggest that prone position is a safe and beneficial procedure during weaning from mechanical ventilation and may contribute to weaning success in preterm infants. To determine the influence of body position on chest wall and pulmonary function, we studied the ventilatory, pulmonary mechanics, and thoracoabdominal motion profiles in 20 preterm infants recovering from respiratory disease who were positioned in both the supine and prone position. Thoracoabdominal motion was assessed from measurements of relative rib cage and abdominal movement and the calculated phase angle (an index of thoracoabdominal synchrony) of the rib and abdomen Lissajous figures. The ventilatory and pulmonary function profiles were assessed from simultaneous measurements of transpulmonary pressure, airflow, and tidal volume. The infants were studied in quiet sleep, and the order of positioning was randomized across patients. The results demonstrated no significant difference in ventilatory and pulmonary function measurements as a function of position. In contrast, there was a significant reduction (-49%) in the phase angle of the Lissajous figures and an increase (+66%) in rib cage motion in prone compared with the supine position. In addition, the degree of improvement in phase angle in the prone position was correlated to the severity of asynchrony in the supine position. We speculate that the improvement in thoracoabdominal synchrony in the prone position is related to alterations of chest wall mechanics and respiratory muscle tone mediated by a posturally related shift in the area of apposition of the diaphragm to the anterior inner rib cage wall and increase in passive tension of the muscles of the rib cage. This study suggests that the mechanical advantage associated with prone positioning may confer a useful alternative breathing pattern to the preterm infant in whom elevated respiratory work loads and respiratory musculoskeletal immaturity may predispose to respiratory failure.
The prone position was significantly superior to the supine position in terms of oxygenation. However, as most participants were ventilated preterm infants, the benefits of prone positioning may be most relevant to these infants. In addition, although placing infants and children in the prone position may improve respiratory function, the association of SIDS with prone positioning means that infants should only be placed in this position while under continuous cardiorespiratory monitoring.