Related Experiment Videos
Lung diffusing capacity and red blood cell volume.
D C Betticher1, J Geiser, A Tempini
1Institut de Physiologie, Université de Fribourg, Switzerland.
Respiration Physiology
|September 1, 1991
Summary
A larger surface area to volume ratio in red blood cells does not improve oxygen transfer in lungs. This study found no significant difference in pulmonary oxygen diffusing capacity (DLO2) when using human versus sheep red blood cells.
Area of Science:
- Physiology
- Respiratory System
- Gas Exchange
Background:
- Red blood cell surface area to volume ratio is a key factor in oxygen transport.
- Understanding factors influencing pulmonary oxygen transfer is crucial for respiratory health.
Purpose of the Study:
- To investigate if a higher surface area to volume ratio of red blood cells enhances oxygen (O2) transfer in the lungs.
- To compare the pulmonary diffusing capacity for O2 (DLO2) using different sized red blood cells.
Main Methods:
- Isolated cat lungs were perfused with suspensions of washed human (large) and sheep (small) red blood cells.
- Lungs were maintained at 27°C, ventilated at 1.0 L/min, and perfused at 110 ml/min with a hemoglobin concentration of 70 g/l.
- Pulmonary diffusing capacity for O2 (DLO2) was calculated under different lung models.
Main Results:
- DLO2 was 0.53 ± 0.10 ml·min⁻¹·mmHg⁻¹ with sheep red cells and 0.52 ± 0.13 ml·min⁻¹·mmHg⁻¹ with human red cells, assuming an inhomogeneous lung model.
- Using a lung model with varying ventilation-perfusion ratios (VA/Q), DLO2 values were 0.86 and 0.93.
- No significant increase in DLO2 was observed with smaller red blood cells (higher surface area per blood volume).
Conclusions:
- A higher red blood cell surface area to volume ratio does not appear to be advantageous for O2 transfer in the lungs.
- The findings suggest other factors may be more limiting for pulmonary gas exchange than red blood cell morphology.
- Further investigation is needed to explore potential explanations for this unexpected result.