Review question
We investigated whether there was a difference in the outcomes for infants and young children with acute respiratory distress syndrome (ARDS) on artificial ventilation who were positioned lying on their abdomen (the prone position), compared to lying on their back (the supine position), or on their side.
Background
ARDS is one of the most frequent causes of hospitalisation and death in infants and young children globally. When children with severe respiratory distress are hospitalised, treatment may include additional oxygen, with or without assisted ventilation. These attempts to increase oxygenation may damage the lungs. Infants and children with respiratory distress placed in particular positions may be more comfortable, breathe more easily, and have better outcomes. However, different positions may also increase the risk of adverse outcomes, such as obstruction of the endotracheal tube (the tube that connects the person to a ventilator), and accidental extubation (removal of the tube). To find out if this was the case, we searched the literature to identify randomised controlled trials (RCTs) and quasi-RCTs comparing two or more body positions for managing infants and children hospitalised with ARDS.
Search date
Our evidence is current to 26 July 2021.
Study characteristics
We included six trials, with a total of 198 participants aged from four weeks to 16 years. The majority were on mechanical ventilators. The timing of interventions ranged from 15 minutes after the child had been settled in a hospital bed, to a maximum of seven days over the duration of the intervention. Only a small number (n = 15) of the children did not have their breathing supported by a ventilator.
Study funding source
The trials included in this review were supported by public agencies.
Key results
Lying on their abdomen appeared to improve the use of oxygen (oxygenation index is the need for additional oxygen relative to the child’s oxygen level) compared to lying on their back. This finding was based on data from three trials with 141 children. Only one trial with 102 children reported adverse effects, which did not differ between the two positions. One trial with 50 children compared lying on their back to other positions, and was not able to show consistent differences in blood oxygenation. There is not enough information to make any conclusions about the benefits and harms of any position in infants and children with acute respiratory distress.
It is important to remember that these children were hospitalised, and on assisted breathing. Because of the association between lying on their abdomen and SIDS, children should not be positioned on their abdomen unless they are in hospital, and their breathing is constantly monitored.
Certainty of the evidence
The findings of this review are limited by the small number of identified trials, five of which had fewer than 40 participants; the short duration of the interventions; and the lack of description of how the study authors addressed the risk of bias in their trials. Overall, we are uncertain how different positions affect our main outcomes, such as oxygenation levels. This means that future research is needed to improve the certainty of our results.
Although included studies suggest that prone positioning may offer some advantage, there was little evidence to make definitive recommendations. There appears to be low certainty evidence that positioning improves oxygenation in mechanically ventilated children with ARDS. Due to the increased risk of SIDS with prone positioning and lung injury with artificial ventilation, it is recommended that hospitalised infants and children should only be placed in this position while under continuous cardiorespiratory monitoring.
Acute respiratory distress syndrome (ARDS) is a significant cause of hospitalisation and death in young children. Positioning and mechanical ventilation have been regularly used to reduce respiratory distress and improve oxygenation in hospitalised patients. Due to the association of prone positioning (lying on the abdomen) with sudden infant death syndrome (SIDS) within the first six months, it is recommended that young infants be placed on their back (supine). However, prone positioning may be a non-invasive way of increasing oxygenation in individuals with acute respiratory distress, and offers a more significant survival advantage in those who are mechanically ventilated. There are substantial differences in respiratory mechanics between adults and infants. While the respiratory tract undergoes significant development within the first two years of life, differences in airway physiology between adults and children become less prominent by six to eight years old. However, there is a reduced risk of SIDS during artificial ventilation in hospitalised infants. Thus, an updated review focusing on positioning for infants and young children with ARDS is warranted. This is an update of a review published in 2005, 2009, and 2012.
To compare the effects of different body positions in hospitalised infants and children with acute respiratory distress syndrome aged between four weeks and 16 years.
We searched CENTRAL, which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE, Embase, and CINAHL from January 2004 to July 2021.
Randomised controlled trials (RCTs) or quasi-RCTs comparing two or more positions for the management of infants and children hospitalised with ARDS.
Two review authors independently extracted data from each study. We resolved differences by consensus, or referred to a third contributor to arbitrate. We analysed bivariate outcomes using an odds ratio (OR) and 95% confidence interval (CI). We analysed continuous outcomes using a mean difference (MD) and 95% CI. We used a fixed-effect model, unless heterogeneity was significant (I2 statistic > 50%), when we used a random-effects model.
We included six trials: four cross-over trials, and two parallel randomised trials, with 198 participants aged between 4 weeks and 16 years, all but 15 of whom were mechanically ventilated. Four trials compared prone to supine positions. One trial compared the prone position to good-lung dependent (where the person lies on the side of the healthy lung, e.g. if the right lung was healthy, they were made to lie on the right side), and independent (or non-good-lung independent, where the person lies on the opposite side to the healthy lung, e.g. if the right lung was healthy, they were made to lie on the left side) position. One trial compared good-lung independent to good-lung dependent positions.
When the prone (with ventilators) and supine positions were compared, there was no information on episodes of apnoea or mortality due to respiratory events. There was no conclusive result in oxygen saturation (SaO2; MD 0.40 mmHg, 95% CI -1.22 to 2.66; 1 trial, 30 participants; very low certainty evidence); blood gases, PCO2 (MD 3.0 mmHg, 95% CI -1.93 to 7.93; 1 trial, 99 participants; low certainty evidence), or PO2 (MD 2 mmHg, 95% CI -5.29 to 9.29; 1 trial, 99 participants; low certainty evidence); or lung function (PaO2/FiO2 ratio; MD 28.16 mmHg, 95% CI -9.92 to 66.24; 2 trials, 121 participants; very low certainty evidence). However, there was an improvement in oxygenation index (FiO2% X MPAW/ PaO2) with prone positioning in both the parallel trials (MD -2.42, 95% CI -3.60 to -1.25; 2 trials, 121 participants; very low certainty evidence), and the cross-over study (MD -8.13, 95% CI -15.01 to -1.25; 1 study, 20 participants).
Derived indices of respiratory mechanics, such as tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP) were reported. There was an apparent decrease in tidal volume between prone and supine groups in a parallel study (MD ‐0.60, 95% CI ‐1.05 to ‐0.15; 1 study, 84 participants; very low certainty evidence). When prone and supine positions were compared in a cross-over study, there were no conclusive results in respiratory compliance (MD 0.07, 95% CI -0.10 to 0.24; 1 study, 10 participants); changes in PEEP (MD -0.70 cm H2O, 95% CI -2.72 to 1.32; 1 study, 10 participants); or resistance (MD -0.00, 95% CI -0.05 to 0.04; 1 study, 10 participants).
One study reported adverse events. There were no conclusive results for potential harm between groups in extubation (OR 0.57, 95% CI 0.13 to 2.54; 1 trial, 102 participants; very low certainty evidence); obstructions of the endotracheal tube (OR 5.20, 95% CI 0.24 to 111.09; 1 trial, 102 participants; very low certainty evidence); pressure ulcers (OR 1.00, 95% CI 0.41 to 2.44; 1 trial, 102 participants; very low certainty evidence); and hypercapnia (high levels of arterial carbon dioxide; OR 3.06, 95% CI 0.12 to 76.88; 1 trial, 102 participants; very low certainty evidence).
One study (50 participants) compared supine positions to good-lung dependent and independent positions. There was no conclusive evidence that PaO2 was different between supine and good-lung dependent positioning (MD 3.44 mm Hg, 95% CI -23.12 to 30.00; 1 trial, 25 participants; very low certainty evidence). There was also no conclusive evidence for supine position and good-lung independent positioning (MD -2.78 mmHg, 95% CI -28.84, 23.28; 25 participants; very low certainty evidence); or between good-lung dependent and independent positioning (MD 6.22, 95% CI -21.25 to 33.69; 1 trial, 25 participants; very low certainty evidence).
As most trials did not describe how possible biases were addressed, the potential for bias in these findings is unclear.