A model investigation of the impact of ventilation–perfusion mismatch on oxygenation during apnea in preterm infants
| Autor: | Vanessa J. Kelly, Philip J. Berger, Malcolm R. Davidson, Malcolm Howard Wilkinson, Scott A. Sands, Bradley A. Edwards |
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| Rok vydání: | 2010 |
| Předmět: |
Statistics and Probability
medicine.medical_specialty Apnea Arterial oxygen Arterial hypoxemia Ventilation perfusion mismatch Models Biological General Biochemistry Genetics and Molecular Biology Hypoxemia Oxygen Consumption Internal medicine medicine Humans Lung General Immunology and Microbiology business.industry Respiration Applied Mathematics Infant Newborn General Medicine Oxygenation Recurrent apnea respiratory tract diseases Lung disease Modeling and Simulation Cardiology medicine.symptom Pulmonary Ventilation General Agricultural and Biological Sciences business Infant Premature |
| Zdroj: | Journal of Theoretical Biology. 264:657-662 |
| ISSN: | 0022-5193 |
| DOI: | 10.1016/j.jtbi.2010.03.041 |
| Popis: | Ventilation–perfusion (V/Q) mismatch is a prominent feature of preterm infants and adults with lung disease. V/Q mismatch is known to cause arterial hypoxemia under steady-state conditions, and has been proposed as the cause of rapid arterial oxygen desaturation during apnea. However, there is little evidence to support a role for V/Q mismatch in the dynamic changes in arterial oxygenation that occur during apnea. Using a mathematical model, we quantified the effect of V/Q mismatch on the rate of desaturation during apnea to ascertain whether it could lead to rates of up to 10% s–1 as observed in preterm infants. We used a lung–body model for the preterm infant that incorporated 50 parallel alveolar–capillary units that were ventilated and perfused with the severity of V/Q mismatch (σ) defined conventionally according to σ=S.D. of the distribution of V/Q ratios. Average desaturation rate 10 s from apnea onset was strongly elevated with worsening V/Q mismatch as a result of an earlier desaturation of low V/Q units compared with high V/Q units. However, V/Q mismatch had little impact after apnea onset, with peak desaturation rate only substantially increased if mismatching caused a lowered resting arterial O2 saturation. In conclusion, V/Q mismatch causes a more immediate onset of desaturation during apnea, and therefore places preterm infants and adults with lung disease at risk of hypoxemic dips. However, V/Q mismatch does not accelerate desaturation rate beyond apnea onset and cannot, therefore, explain the rapid desaturation observed during recurrent apnea in preterm infants. |
| Databáze: | OpenAIRE |
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