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Effect of posture on oxygenation and respiratory muscle strength in convalescent infants
G Dimitriou1, A Greenough, L Pink
1Children Nationwide Regional Neonatal Intensive Care Unit, King's College Hospital, London, UK.
Insights
Respiratory muscle strength did not explain improved oxygenation in prone or head-up tilted positions in convalescent infants. Oxygenation was highest in these positions, but maximal inspiratory pressure was greatest in the supine posture.
Area of Science:
- Neonatal physiology
- Respiratory medicine
- Pediatric critical care
Background:
- Convalescent neonates often experience altered oxygenation related to body posture.
- Understanding the physiological mechanisms behind these postural effects is crucial for optimizing respiratory support.
Purpose of the Study:
- To investigate the relationship between respiratory muscle strength and postural effects on oxygenation in convalescent neonates.
- To determine if differences in maximal inspiratory pressure (PIMAX) account for improved oxygen saturation (SaO2) in various postures.
Main Methods:
- A study involving convalescent infants assessed oxygen saturation (SaO2) and maximal inspiratory pressure (PIMAX) in three postures: supine, supine with 45-degree head-up tilt, and prone.
- A secondary study examined the influence of head position in the supine posture.
- Participants included infants with a median gestational age of 34.5 weeks (first study) and 33 weeks (second study).
Main Results:
- Oxygenation (SaO2) was significantly higher in the prone and 45-degree head-up tilted supine positions compared to the standard supine position (p<0.001).
- Respiratory muscle strength (PIMAX) was significantly greater in the supine and 45-degree head-up tilted supine positions compared to the prone position (p<0.001).
- Head position did not alter the observed effects of posture on PIMAX or SaO2.
Conclusions:
- The superior oxygenation observed in the prone posture in convalescent infants is not attributable to enhanced respiratory muscle strength.
- Respiratory muscle strength was highest in the supine posture, suggesting other mechanisms contribute to improved oxygenation in prone and head-up positions.
- These findings highlight the complex interplay between posture, respiratory mechanics, and oxygenation in neonates.
Objective:
To determine if differences in respiratory muscle strength could explain any posture related effects on oxygenation in convalescent neonates.
Methods:
Infants were examined in three postures: supine, supine with head up tilt of 45 degrees, and prone. A subsequent study was performed to determine the influence of head position in the supine posture. In each posture/head position, oxygen saturation (SaO2) was determined and respiratory muscle strength assessed by measurement of the maximum inspiratory pressure (PIMAX).
Patients:
Twenty infants, median gestational age 34.5 weeks (range 25-43), and 10 infants, median gestational age 33 weeks (range 30-36), were entered into the first and second study respectively.
Results:
Oxygenation was higher in the prone and supine with 45 degrees head up tilt postures than in the supine posture (p<0.001), whereas PIMAX was higher in the supine and supine with head up tilt of 45 degrees postures than in the prone posture (p<0.001). Head position did not influence the effect of posture on PIMAX or oxygenation.
Conclusion:
Superior oxygenation in the prone posture in convalescent infants was not explained by greater respiratory muscle strength, as this was superior in the supine posture.
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