可以直接根据整理好的内容生成 Quiz 进行复习,需要时再导出到 Anki;完成的总结笔记还可导出为 PDF 或 Word,用于打印、分享或继续编辑。
Respiratory system notes
Alveolar ventilation
Alveolar ventilation accounts for dead space when relating tidal volume to respiratory rate. Rapid, shallow breathing can reduce gas exchange even when minute ventilation appears unchanged.
VA = (VT - VD) × RR
Hypoventilation can raise PaCO₂ and cause respiratory acidosis.
Gas exchange and the oxygen dissociation curve
O₂ diffuses from alveoli to blood, while CO₂ moves from blood to alveoli. Lower pH, higher CO₂, and higher temperature shift the oxygen dissociation curve to the right.
Right shift: oxygen is released to tissues more easily.
Left shift: hemoglobin holds oxygen more tightly.
Causes of hypoxemia
Compare V/Q mismatch, diffusion defect, shunt, and hypoventilation using the A–a gradient and response to supplemental oxygen.
V/Q mismatch: increased A–a gradient and usually improves with oxygen.
Shunt: PaO₂ improves only slightly despite oxygen.
Hypoventilation: PaCO₂ rises while the A–a gradient may stay normal.
Obstructive ventilatory defect
Asthma and COPD characteristically reduce FEV₁/FVC. Expiration becomes prolonged, air trapping develops, and residual volume can increase.
Chronic bronchitis: productive cough for at least 3 months in 2 consecutive years.